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Biosolids, sewage sludge, and composts are applied to agricultural land for nutrient recovery and soil organic matter replenishment, aligning with sustainable development goals. However, they may contain per- and polyfluoroalkyl substances (PFAS) that can enter the food chain through plant bioaccumulation and leaching into the groundwater. This study analyzed 80 PFAS compounds in sewage sludge, biosolids, commercial composts, and chemical fertilizers in Quebec, Canada, using UHPLC-HRMS (Orbitrap Q-Exactive). PFAS concentrations ranged from 18 to 59 µg/kg in commercial composts, 9.8 to 213 µg/kg in pulp and paper sludge, 15 to 705 µg/kg in sewage sludge, 12 to 1310 µg/kg in biosolids, and 14.6 µg/kg on average in biosolids ash. Dominant PFAS classes included diPAPs, sulfonamides, PFCAs, and PFSAs. High diPAPs concentrations indicated widespread use in domestic, commercial, or industrial applications. This study also observed a negligible correlation between soil organic carbon and PFAS concentration in the biowastes signifying a stronger influence due to different WWTP configurations, the quality of the wastewater inputs and other medium's properties that could affect PFAS partitioning to the biowastes. Environmental assessments showed PFAS loads of up to 30 µg/kg soil from a single application, within some regulatory limits. However, repeated applications could lead to PFAS accumulation in soil, posing risks to crops and groundwater., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The land application of biosolids as a management practice is considered a beneficial use for improving crop yield and reducing the need for other fertilizers. PFAS enter wastewater treatment plants through collection networks, including industrial discharges, the use of PFAS-containing products, and runoff. Therefore, PFAS may be present in biosolids derived from sewage sludge. The objectives of this study were to evaluate PFAS levels in biosolids samples collected at two wastewater treatment plants operated by the Miami Dade Water and Sewer Department (MDWASD): (1) the South District Wastewater Treatment Plant (SDWWTP) which received landfill leachate and (2) the Central District Wastewater Treatment Plant (CDWWTP). Sludge samples were collected after thickening, anaerobic digestion, and dewatering processes. The samples were subjected to batch leaching tests for 30 days. After the leaching tests, the PFAS levels in the liquid and solid fractions were analyzed for 40 PFAS. The findings show that during the aeration process (i.e., activated sludge process), PFAS are removed from the wastewater and accumulate on the solids. When the thickened sludge is digested, some PFAS are released to the liquid phase as the volatile solids decompose. During the dewatering process by centrifugation, PFAS that are partitioned to the liquid phase are removed, reducing PFAS content in the dewatered biosolids. Of the 40 PFAS analyzed, 24 were detected in leachate or solid residue samples. Samples from the SDWWTP had higher levels of PFAS due to the contribution from landfill leachate discharged to this facility. The partitioning of PFAS between the liquid phase and solid residue after 30 days of mixing indicates that the majority of PFAS in the biosolids are highly soluble and have a high tendency to be mobilized (by runoff, irrigation, precipitation) after land application. The fate profiles of PFAS biosolids were evaluated in terms of their solubility and retardation characteristics., Competing Interests: Declaration of competing interest No conflict of interest exists. I wish to confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The aim of this work was to stabilize excess sludge (ES) coming from a wastewater treatment plant (WWTP) by vermistabilization and to evaluate ecotoxicological effects over the earthworm species Eisenia fetida. Three mixtures were made up in triplicate using different volume ratios of ES and soil (S) (100% ES, 70:30% ES:S and 30:70% ES:S in wet weight basis). Earthworms were added in order to compare vermicomposting vs. natural stabilization. The mixtures were monitored over 130 days through physical, chemical, pathological and biological analysis, following quality standards depicted in the US EPA 40 CFR Part 503, local regulations and background studies. Histopathological samples were processed as biomarkers of acute and chronic toxicity on earthworms, and germination assays were performed at the end of the experiment to assess phytotoxicity. In terms of pathogen depletion comparing initial and final values from each treatment, the mixtures with higher ES proportions (70 and 100%) with earthworms were the most efficient ones registering 64.8 and 75.5% of reduction of fecal coliforms (FC) respectively, while the lowest ES proportion with earthworms (30%) showed 54.7%. Final pathogens content in all the treatments with earthworms were significantly lower (ranged from 1360 to 1760 MPN g total solids -1 ) than the values registered in treatments without earthworms (ranged from 2400 to 4000 MPN g total solids -1 ) (p < 0.05). However, none of the treatments attained class A categorization (FC ≤ 1000 MPN g total solids -1 ) in terms of FC. Also, values of mean cocoon production and hatched juveniles along time were significantly higher in the treatments with 100 and 70% ES (p < 0.05), while the higher mean adult biomass was detected in the treatment with 30% ES. Volatile solids decrease ranged between 8.45 and 22.34% in treatments with earthworms and all values of specific oxygen uptake rate were below 1.5 mg O 2  h  -1  g total solids  -1 . There were not negative effects over behavior or reproduction of E. fetida adults, nor the presence of external and internal injuries. Final products from mixtures with earthworms presented a humus-like structure, were odorless and reached maturity values -presenting no phytotoxicity-with significant differences between germination index values of treatments with and without earthworms (p < 0.05). Vermistabilization is a successful eco-technology to sanitize excess sludge, acquiring an added-value material and contributing to its revalorization as organic amendments or fertilizers in soils within the circular economy framework and the United Nations' Sustainability Development Goals., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Limited information is available on the removal of per- and polyfluoroalkyl substances (PFAS) in anaerobic digestion (AD). Τhe fate of six PFAS was studied in thermophilic bioreactors in the presence of granular activated carbon (GAC) and voltage application. Reactors with GAC exhibited lower concentrations of volatile fatty acids and higher methane production compared to those with and without the application of voltage. Analysis of PFAS in dissolved and solid phase showed that their distribution was dependent on perfluorocarbon chain length and functional group. Mass balances showed that PFAS were not removed during conventional AD or after applying voltage; however, significant removal (up to 61 ± 8 %) was observed in bioreactors with GAC for perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorooctane sulfonate (PFOS). Biomass characterization showed that in these bioreactors, the relative abundance of Acinetobacter and Pseudomonas was higher, indicating their potential role in PFAS biotransformation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Wastewater treatment plants (WWTP) are facilities where municipal wastewater undergoes treatment so that its organic load and its pathogenic potential are minimized. Sewage sludge is a by-product of this process and when properly treated is preferentially called "biosolids". These treatments may include some or most of the following: thickening, dewatering, drying, digestion, composting, liming. Nowadays it is almost impossible to landfill biosolids, which however can well be used as crop fertilizers. Continuous or superfluous biosolids fertilization may negatively affect non-target organisms such as soil macro-organisms or even plants. These effects can be depicted through bioassays on terrestrial animals and plants. It has been shown that earthworms have been affected to various degrees on the following endpoints: pollutants' bioaccumulation, viability, reproduction, avoidance behavior, burrowing behavior. Collembola have been affected on viability, reproduction, avoidance behavior. Other terrestrial organisms such as nematodes and diplopods have also shown adverse health effects. Phytotoxicity have been caused by some biosolids regimes as measured through the following endpoints: seed germination, root length, shoot length, shoot biomass, root biomass, chlorophyll content, antioxidant enzyme activity. Very limited statistical correlations between pollutant concentrations and toxicity endpoints have been established such as between juvenile mortality (earthworms) and As or Ba concentration in the biosolids, between juvenile mortality (collembola) and Cd or S concentration in the biosolids, or between phytotoxicity and some extractable metals in leachates or aquatic extracts from the biosolids; more correlations between physicochemical characteristics and toxicity endpoints have been found such as between phytotoxicity and ammonium N in biosolids or their liquid extracts, or between phytotoxicity and salinity. An inverse correlation between earthworm/collembola mortality and stable organic matter has also been found. Basing the appropriateness of biosolids only on chemical analyses for pollutants is not cost-effective. To enable risk characterization and subsequent risk mitigation it is important to apply a battery of bioassays on soil macro-organisms and on plants, utilizing a combination of endpoints and established protocols. Through combined analytical quantification and toxicity testing, safe use of biosolids in agriculture can be achieved., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The pervasive presence of poly- and perfluoroalkyl substances (PFAS) in diverse products has led to their introduction into wastewater systems, making wastewater treatment plants (WWTPs) significant PFAS contributors to the environment. Despite WWTPs' efforts to mitigate PFAS impact through physicochemical and biological means, concerns persist regarding PFAS retention in generated biosolids. While numerous review studies have explored the fate of these compounds within WWTPs, no study has critically reviewed their presence, transformation mechanisms, and partitioning within the sludge. Therefore, the current study has been specifically designed to investigate these aspects. Studies show variations in PFAS concentrations across WWTPs, highlighting the importance of aqueous-to-solid partitioning, with sludge from PFOS and PFOA-rich wastewater showing higher concentrations. Research suggests biological mechanisms such as cytochrome P450 monooxygenase, transamine metabolism, and beta-oxidation are involved in PFAS biotransformation, though the effects of precursor changes require further study. Carbon chain length significantly affects PFAS partitioning, with longer chains leading to greater adsorption in sludge. The wastewater's organic and inorganic content is crucial for PFAS adsorption; for instance, higher sludge protein content and divalent cations like calcium and magnesium promote adsorption, while monovalent cations like sodium impede it. In conclusion, these discoveries shed light on the complex interactions among factors affecting PFAS behavior in biosolids. They underscore the necessity for thorough considerations in managing PFAS presence and its impact on environmental systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Research has evolved on aerobic granular sludge (AGS) process, but still there are very few studies on the treatment of excess AGS sludge, with almost none considering its aerobic digestion. Here therefore, the aerobic digestibility of typical AGS sludge was assessed. Granules were produced from acetate-based synthetic wastewater (WW) and were subjected to aerobic digestion for 64 d. The stabilization process was monitored over time through physical-chemical parameters, oxygen uptake rates (OUR) and 16S rRNA gene sequencing. The microbial analyses revealed that the cultivated granules were dominated by slow-growing bacteria, mainly ordinary heterotrophic organisms with potential for polyhydroxyalkanoates (PHA) aerobic storage (PHA-OHOs), polyphosphate and glycogen accumulating organisms (PAOs and GAOs), fermentative anaerobes and nitrifiers (AOB and NOB). Differential abundance analysis of the bacterial data (before versus after digestion) discriminated between the most vulnerable microbiome genera and those most resistant to aerobic digestion. Furthermore, modeling of the stabilization process determined that the endogenous decay rate constant (b H ) for the heterotrophs present in the granules was notably low; b H  = 0.05 d -1 (average), four times less than for common activated sludge (AS), which is rated at 0.2 d -1 . For first time, the research reveals another important feature of AGS sludge, i.e. the slow-decaying character of its bacteria (along with their known slow-growing character). This results in slower stabilization, need of bigger digesters and reconsideration of the specific OUR limits in biosolids regulations (SOUR limit of 1.5 mg/gTSS.h), for waste AGS compared to conventional waste AS. The study suggests that aerobic digestion of waste AGS (fully-granulated) could differ from that of conventional AS. Future work is needed on aerobic digestibility of real AGS sludges from municipal and industrial WWs, compared to synthetic WWs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Recently, there has been a growing inclination towards utilizing primary sludge (PS) fermentation prior to anaerobic digestion (AD) in water resource recovery facilities (WRRFs), where sludge liquor containing volatile fatty acids is used for biological nutrient removal. Nevertheless, using a low-temperature thermal hydrolysis process (THP) to improve AD in WRRFs adopting PS fermentation remains an area that has received limited research attention. Here, we studied the impact of THP (90 °C, 90 min) on anaerobic co-digestion of thickened waste activated sludge (TWAS) and fermented primary sludge (FPS) under varying solids retention times (SRTs) in semi-continuous mode. The study involved two THP schemes: scheme 1, where THP was done for both TWAS and FPS, and scheme 2, where THP was applied to TWAS only. The results demonstrated that reducing SRT from 20 to 15 and 10 d leads to decreased methane yield in both schemes. However, THP significantly enhances methane production, showing improvements of up to 37.9 % (scheme 1) and 31.2 % (scheme 2) under a 15-d SRT. Furthermore, while decreasing SRT increased the proliferation of antibiotic resistance genes (ARGs), thermal hydrolysis could effectively reduce most ARGs, indicating its potential to mitigate antibiotic resistance in the AD process. Overall, these results provide useful perceptions regarding the potential adoption of low-temperature THP in WRRFs with PS fermentation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Plastics are ubiquitous in virtually every environment on earth. While the specific sources of plastics entering wastewater are not well known, growing evidence suggests sewage sludge (biosolids) can be a sink for plastics. One potential source could be the sewerage pipe materials used to transport sewage between premises and wastewater treatment plants (WWTPs). To evaluate the significance of sewerage piping as a source of biosolids plastics concentrations, we compared the proportion of the total network (by length and surface area) of polyethylene (PE), polyvinylchloride (PVC), and polypropylene (PP) pipes from 10 WWTPs against their biosolids mass concentrations (mg plastic/g biosolid). Among the 10 catchments, the percentage of the network consisting of PP piping ranged from 0 to 1 %, with 0.8-21 % for PE, and 8-73 % for PVC. Biosolids plastics concentrations ranged from 0.09 to 8.62 mg/g (mg plastic/g biosolid) for PP and PE, respectively. For all three plastics, there was no significant Pearson correlation (r < 0.4) between the biosolids concentration (dry weight mg/g) and the proportion of the network material of the sewerage piping as plastic (either length or surface area). A comparison of trade waste entering a subset of 6 WWTP showed the highest biosolid principal components analysis (PCA) associations between loads of plastics (g/day) and automotive wash bays, general manufacturing, hospitals, laboratories, food manufacturing, laundry and dry cleaning, and cooling towers. A stepwise regression analysis indicated pipe length and surface area, as well as automotive wash bays and food manufacturing may be significant. While our data gave mixed results on the attribution of the sources of plastics entering WWTPs, it suggests that sewerage infrastructure and trade waste may play some role. Future studies should investigate the leachability of sewerage infrastructure and contributions from specific trade waste categories to determine their significance in plastics entering WWTPs., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Ben Tscharke reports financial support was provided by Australian Research Council. Elvis Okoffo reports financial support was provided by Australian Research Council. Jiaying Li reports financial support was provided by Australian Research Council. Kevin Thomas reports financial support was provided by Australian Research Council., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

This study deals with energy and agronomic valorisation by anaerobic co-digestion with temperature and microorganism phase separation of sewage sludge, vinasse and poultry manure, with the aim of achieving an integral waste management, obtaining bioenergy and biofertilizer that returns nutrients to the soil in a natural way. The yields obtained were 40 mL H 2 /gVS and 391 mLCH 4 /gVS. The resulting effluent showed more than 98 % removal of E. coli and Total Coliforms, as well as total removal of Salmonella. The results obtained in the phytotoxicity tests showed that all the proportions studied had phytostimulant and phytonutrient properties, with 20 % having the highest germination index (GI) with mean values of 145.30 %. Finally, the agronomic trial carried out with strawberry crops (Fragaria sp.) showed that the addition of this biosolid has fertilising properties and can be used as an agronomic amendment, with an increase of 145 % in fresh weight and 102.5 % in dry weight, and fruit production doubled with respect to the control. The ANOVA statistical study corroborated that there were significant differences in crop growth when applying different proportions of biofertilizer in the fertilizer. Therefore, these results show that this technology is promising and would contribute environmentally, socially and economically to the transfer towards a circular economy model., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Municipal biosolids contain organic and inorganic phosphorus (P) that could be recovered for reuse as P fertilizer. Inorganic P compounds include iron phosphates that precipitate and/or adsorbed phosphate ions as a consequence of soluble iron addition in order not to exceed total phosphorus (TP) emission limits. The inorganic orthophosphate (o-Pi) minerals within biosolids can have low solubilities. One P recovery strategy is to maximize the dissolution of o-Pi from biosolids for reuse. Dissolving iron phosphates in biosolids by adding sodium sulfide was assessed as an o-Pi dissolution strategy. 10 % w/w biosolids slurries with a total phosphorus (TP) of 0.97 ± 0.03 mmol P/dry g were mixed with sulfide/TP (S 2 - /TP) molar ratios from 0 to 4 for up to 96 h. The maximum o-Pi concentration (48 ± 7 mM, or 42 ± 6 % of TP) was obtained for 4 S 2- /TP after 24 h at room temperature (RT). Iron concentrations measured by colorimetry (ferrozine) reduced from 0.6 ± 0.1 mM to less than 0.01 mM (S 2 - /TP > 1). X-ray diffraction and FTIR suggest that sulfide treatment preferentially dissolved amorphous o-Pi-containing solids, vivianite, and minerals with iron, aluminum, phosphate, sulfate, and other subsitutions. Poorly crystalline erdite (NaFeS 2 ·2H 2 /TP over 47 h. Sulfide addition could also increase the risk of construction material corrosion, and reduce the efficiency of P recovery by precipitation. There are disadvantages to using sulfide to dissolve o-Pi from biosolids as a potential P recovery process.2 - /TP treatment ratios ≥ 2. Incubation at RT or 37 °C did not affect the o-Pi concentrations for 0 or 4 S 2 - /TP over 47 h. Sulfide addition could also increase the risk of construction material corrosion, and reduce the efficiency of P recovery by precipitation. There are disadvantages to using sulfide to dissolve o-Pi from biosolids as a potential P recovery process., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The Coronavirus Disease 2019 (COVID-19) pandemic led to over 770 million confirmed cases, straining public healthcare systems and necessitating extensive and prolonged use of synthetic chemical drugs around the globe for medical treatment and symptom relief. Concerns have arisen regarding the massive release of active pharmaceutical ingredients (APIs) and their metabolites into the environment, particularly through domestic sewage. While discussions surrounding this issue have primarily centered on their discharge into aquatic environments, particularly through treated effluent from municipal wastewater treatment plants (WWTPs), one often overlooked aspect is the terrestrial environment as a significant receptor of pharmaceutical-laden waste. This occurs through the disposal of sewage sludge, for instance, by applying biosolids to land or non-compliant disposal of sewage sludge, in addition to the routine disposal of expired and unused medications in municipal solid wastes. In this article, we surveyed sixteen approved pharmaceuticals for treating COVID-19 and bacterial co-infections, along with their primary metabolites. For this, we delved into their physiochemical properties, ecological toxicities, environmental persistence, and fate within municipal WWTPs. Emphasis was given on lipophilic substances with log K ow >3.0, which are more likely to be found in sewage sludge at significant factions (25.2%-75.0%) of their inputs in raw sewage and subsequently enter the terrestrial environment through land application of biosolids, e.g., 43% in the United States and as high as 96% in Ireland or non-compliant practices of sewage sludge disposal in developing communities, such as open dumping and land application without prior anaerobic digestion. The available evidence underscores the importance of adequately treating and disposing of sewage sludge before its final disposal or land application in an epidemic or pandemic scenario, as mismanaged sewage sludge could be a significant vector for releasing pharmaceutical compounds and their metabolites into the terrestrial environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Sewage sludge is a byproduct of sewage treatment, whereas landfill leachate is a complex wastewater generated by the decomposition of solid waste. These byproducts require adequate management, and one option for the sludge is the thermal treatment by pyrolysis to produce biochar. The resulting biosolid can be used as an adsorbent to treat landfill leachate. The main objective of this research was to remove recalcitrant organic matter from landfill leachate by adsorption onto biochar produced from sewage sludge. Aerobic and anaerobic sludges were pyrolyzed at 450, 650 and 850 °C, under residence times of 60, 90 and 120 min. Temperature had a positive and more significant impact on the characteristics of the biochars produced, and consequently on the adsorption of recalcitrant organic matter. However, the impact of residence time was less intense and, in some cases negative. Biochars produced from both aerobic and anaerobic sludge pyrolyzed at 850 °C for 120 and 60 min, respectively, showed higher specific surface areas (114.4 m 2 g -1 and 104.2 m 2 g -1 , respectively) compared with those pyrolyzed at 450 °C and 650 °C. The biochar from anaerobic sludge produced at 850 °C and 60 min showed the best performance regarding the adsorption process, with chemical oxygen demand (COD), dissolved organic carbon (DOC), and color removals from the leachate of 32%, 36%, and 41%, respectively. The results of adsorption capacity for this biochar from anaerobic sludge were 26.1 mg g -1 for COD and 7.9 mg g -1 for DOC. The adsorption of recalcitrant organic matter from leachate was evidenced by the decrease in the UV-Vis absorbances and fluorescence intensities. It indicates that recalcitrant and humic substances were removed mainly by biochars pyrolyzed at 850 °C. Thus, the results allow to stress that the pyrolysis of sewage sludge to produce biochar is a promising alternative to sludge treatment, and the biochar may be applied as a pre-treatment of landfill leachate since it successfully removed the recalcitrant organic matter., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Although different quantification methods are extensively used in environmental chemistry, the impact of the choice of method on the quality and range of analytical results is understudied. This two-part study consists of (a) in-lab evaluation and (b) a traditional meta-analysis (n = 66) of commonly used quantification methods): (i) external calibration; (ii) isotope dilution method with authentic target analogs; (iii) isotope dilution with non-target standards; and (iv) standard addition prior to LC-MS/MS in liquid chromatography tandem mass spectrometry (LC-MS/MS) by example of antibiotics in sewage sludge from across the U.S. Using method (i) as the benchmark quantification method for the antibiotic erythromycin in biosolids, other quantification methods resulted in an overestimation (110-450 %) or an underestimation (10-60 %). Using the method (iv) as the benchmark for other compounds resulted in an overestimation (101-14,700 %) or an underestimation (6-98 %). Matrix effects were also observed and were dependent on the matrix and analyte type. For example, in the case of erythromycin, all sample matrices showed signal suppression. This study showed that in the absence of isotopically labeled analogs, the most accurate alternate quantification method may need to be experimentally determined depending on the analyte. Analysis of published literature on pharmaceuticals in sewage sludge indicated that isotope dilution with authentic target analog is most commonly used, followed by non-target isotope standards, standard addition, and finally external calibration., Competing Interests: Declaration of competing interest R.U.H. is a cofounder of AquaVitas, an Arizona State University startup company providing commercial services in wastewater-based epidemiology. R.U.H. also is the founder of OneWaterOneHealth, a nonprofit project of the Arizona State University Foundation., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Microplastics have been reported in wastewater treatment works across the world. The majority of microplastics are removed during the wastewater treatment process, with removal efficiencies between 57 % to 99 %. What happens to the microplastics removed from the wastewater, and how they accumulate in sewage sludge and biosolids (by-products of the wastewater treatment process), remains a topic of high interest. Here we systematically reviewed the current state of knowledge on the presence, concentration, and characteristics of microplastics in sewage sludge and biosolids globally to understand how biosolids may act as a pathway for microplastic pollution to soils. A systematic search was performed on the Web of Science and Science Direct databases. Sixty-five studies reporting on microplastic pollution in sewage sludge and biosolid products were identified, spanning twenty-five countries. Reported microplastic concentrations varied considerably from 0.193 microplastics/g to 1.69 × 10 5 microplastics/g with a median microplastic concentration of 22.41 microplastics/g, illustrating how many microplastics are captured during the wastewater treatment process, and retained in the sewage sludge. The extent to which biosolid recycling pollutes the terrestrial environment was compared between countries. High numbers of microplastics were estimated to reach fields via biosolid application with a wide variation of 8.2 × 10 10 to 1.29 × 10 15 microplastics/year between sixteen countries, although there was no significant difference in microplastic concentration between fields with a history of biosolid applications and control fields. The comparative risk this delivery of approx. 0.4 to 6430 tonnes of microplastics poses compared to the environmental benefits of nutrient and carbon recycling associated with biosolids reuse, or compared to other sources of microplastic pollution remains a global research imperative. The next step in scientific research needs to focus on solutions to the biosolid and circular economy conundrum - biosolids are a valuable source of nutrients but contain high concentrations of microplastics, which are ultimately entering the terrestrial environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

The occurrence of antibiotic-resistant bacteria (ARB) in wastewater treatment plants (WWTPs) has become an occupational and environmental concern. WWTPs are engineered systems that treat wastewater to meet public health standards before release into the environment. The residuals, as either effluent or solids, are then discharged or beneficially recycled into the environment. Since these wastes contain a diverse array of microorganisms, some of which are resistant to commonly used antibiotics, there is a potential for these organisms to spread in the environment via residual recycling and effluent discharge. Human infections with ARB are increasing, and it is not well known how the interaction between humans and the environment plays a role in this process. WWTP workers, who are on the front lines, may come into direct contact with materials containing these microbes. This study aimed to determine the number of ARB present in both air and sewage sludges in a WWTP using nonselective media supplemented with two antibiotics (ciprofloxacin and azithromycin). The densities of total heterotrophic bacteria, ciprofloxacin-resistant bacteria, and azithromycin-resistant bacteria were 7.82 × 10 5 - 4.7 × 10 9 , 7.87 × 10 3 - 1.05 × 10 8 , and 2.27 × 10 5 - 1.16 × 10 9 CFU/g, respectively. The prevalence [(concentration on medium with antibiotics/concentration on medium without antibiotics) × 100] of ciprofloxacin-resistant bacteria in treated sludge was twice as low as in digested sludge and approximately three times lower than in raw sludge. For azithromycin, the prevalence of resistant bacteria in treated sludge was about the same in digested and nearly twice lower than in raw sludge. Despite a marked reduction in the mean prevalence of resistant bacteria in dewatered treated sludge for both antibiotics, these differences were not significant. The highest prevalence of antibiotic resistance was observed for azithromycin. Similarly, the prevalence of airborne azithromycin-resistant bacteria inside the belt filter press room (BFPR) was nearly seven times higher than the prevalence of airborne ciprofloxacin-resistant bacteria. These concentrations of ARB were not negligible and may represent an exposure pathway for some workers in WWTPs.

Anaerobic digestion (AD) and composting are commonly utilized sludge management methods however, the influence of different coagulant types on these biological processes and their stabilized biomass characteristics have not been fully explained. In this study, the effect of the coagulant used in municipal wastewater treatment on the biological stabilization of sludge was investigated. Fully controlled and monitored small-scale AD and composting bioreactors were utilized. The coagulants tested included an inorganic coagulant (IC), polyaluminium chloride (PAC), and organic coagulants, (OC) polyamine (pAmine) and chitosan (Chit). Overall, the coagulant applied showed a measurable influence on the biological stabilization of sludge. The presence of complex organics compounds from OC in the sludge biomass was found to decrease biomass biodegradability while increasing gas production. During AD, Chit-sludge achieved higher biogas production than pAmine- and PAC-sludges (13 % and 16 %, respectively, in Nm 3 CH 4 t -1 VS). In composting, pAmine-sludge achieved the highest feedstock temperature (34-35 °C) and CO 2 gas emissions, followed by Chit- (33 °C) and PAC-sludges (32 °C). Generally, tot-P concentration in PAC-sludge was higher than in pAmine and Chit-sludges both before (20, 17 and 15 g/kg DM, consecutively) and after AD (23, 21 and 20.5 g/kg DM, consecutively), and during the composting (31, 29.5 and 26 g/kg DM, consecutively) process. Tot-N concentrations (g/kg DM) showed a substantial increase after AD (pAmine and PAC ca 50 % and Chit 81 %), while a decrease was observed after composting, specifically in PAC-sludge (PAC 28 %, pAmine and Chit ⁓5 %). The selection of the most suitable coagulant by wastewater treatment facilities depends on the objective of the biological stabilization process. In cases where AD is applied and biogas yield is selected as the target output, the semi-natural OC Chit was found to be the best option among the coagulants tested. Comparably, when the nutrient content of resulting biosolids (AD or composting) is more relevant, it was found that OC-produced sludge contained higher N concentrations, while IC-produced sludge contained slightly higher P concentrations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Sewage sludge should be stabilized for its beneficial use and pathogens, among other factors, should comply with environmental regulations. Three sludge stabilization process were compared to assess their suitability for producing Class A biosolids: MAD-AT (mesophilic (37 °C) anaerobic digestion (MAD) followed by an alkaline treatment (AT)); TAD (thermophilic (55 °C) anaerobic digester); and TP-TAD (mild thermal (80 °C, 1 h) pretreatment (TP) followed by a TAD). E. coli and Salmonella spp. were determined, differentiating three possible states: total cells (qPCR), viable cells using the propidium monoazide method (PMA-qPCR), and culturable cells (MPN). Culture techniques followed by the confirmative biochemical tests identified the presence of Salmonella spp. in PS and MAD samples, while the molecular methods (qPCR and PMA-qPCR) showed negative results in all samples. The TP + TAD arrangement reduced the concentration of total and viable E. coli cells in a greater extent than the TAD process. However, an increase of culturable E. coli was observed in the corresponding TAD step, indicating that the mild thermal pretreatment induced the viable but non-culturable state in E. coli. In addition, the PMA technique did not discriminate viable from non-viable bacteria in complex matrices. The three processes produced Class A biosolids (fecal coliforms < 1000 MPN/gTS and Salmonella spp, < 3 MPN/gTS) maintaining compliance after a 72 h storage period. It appears that the TP step favors the viable but not culturable state in E. coli cells, a finding that should be considered when adopting mild thermal treatment in sludge stabilization process arrangements., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Primary sludge (PS) is associated with public health and environmental risks, so regulations focus on reducing the pathogenic and heavy metal contents of the treated material (biosolids), intended for soil amendments and land reclamation. The regulations set limits for Escherichia coli (or fecal coliforms), Salmonella spp., helminth eggs and enterovirus. However, the potential risk due to antibiotic resistant bacteria (ARB) and other human potential pathogenic bacteria (HPB) are not considered. In this work, three sludge treatment processes, having in common an anaerobic digestion step, were applied to assess the removal of regulated bacteria (fecal coliforms, Salmonella spp), ARB and HPB. The treatment arrangements, fed with PS from a full-scale wastewater treatment plant were: 1) Mesophilic anaerobic digestion followed by alkaline stabilization post-treatment (MAD-CaO); 2) Thermophilic anaerobic digestion (TAD) and, 3) Pre-treatment (mild thermo-hydrolysis) followed by TAD (PT-TAD). The results address the identification, quantification (colony forming units) and taxonomic characterization of ARB resistant to β-lactams and vancomycin, as well as the taxonomic characterization of HPB by sequencing with PacBio. In addition, quantification based on culture media of fecal coliforms and Salmonella spp. is presented. The capabilities and limitations of microbiological and metataxonomomic analyses based on PacBio sequencing are discussed, emphasizing that they complement each other. Genus Aeromonas, Acinetobacter, Citrobacter, Enterobacter, Escherichia, Klebsiella, Ochrobactrum, Pseudomonas and Raoultella, among others, were found in the PS, which are of clinical or environmental importance, being either HPB, HPB-ARB, or non-pathogenic ARB with the potentiality of horizontal gene transfer. Based on the analysis of fecal coliforms and Salmonella spp., the three processes produced class A (highest) biosolids, suitable for unrestricted agriculture applications. Mild thermo-hydrolisis was effective in decreasing ARB cultivability, but it reappeared after the following TAD. O. intermedium (HPB-ARB) was enriched in MAD and TAD while Laribacter hongkongensis (HPB) did persist after the applied treatments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Increasingly stringent limits on nutrient discharges are motivating water resource recovery facilities (WRRFs) to consider the implementation of sidestream nutrient removal or recovery technologies. To further increase biogas production and reduce landfilled waste, WRRFs with excess anaerobic digestion capacity can accept other high-strength organic waste (HSOW) streams. The goal of this study was to characterize and evaluate the life-cycle global warming potential (GWP), eutrophication potential, and economic costs and benefits of sidestream nutrient management and biosolid management strategies following digestion of sewage sludge augmented by HSOW. Five sidestream nutrient management strategies were analyzed using environmental life-cycle assessment (LCA) and life-cycle cost analysis (LCCA) for codigestion of municipal sewage sludge with and without HSOW. As expected, thermal stripping and ammonia stripping were characterized by a much lower eutrophication potential than no sidestream treatment; significantly higher fertilizer prices would be needed for this revenue stream to cover the capital and chemical costs. Composting all biosolids dramatically reduced the GWP relative to the baseline biosolid option but had slightly higher eutrophication potential. These complex environmental and economic tradeoffs require utilities to consider their social, environmental, and economic values in addition to present or upcoming nutrient discharge limits prior to making decisions in sidestream and biosolids management.

This study assessed, for the first time ever, the use of basic oxygen furnace (BOF) slag as alkalinizing material during the sludge conditioning, as an environmentally-friendly alternative to CaO and other conventional alkalis. Its effects on the dewatering, solubilisation and stabilization of sewage sludge were studied, testing increasing dosages of BOF from 0 to 6 gBOF/gTSS 0 at room temperature and under constant mechanical agitation was evaluated. Results revealed that the addition of BOF slag to sewage sludge produced similar degrees of solubilisation to those obtained using lime, reaching a maximum of 34% of total COD for 3.00 gBOF/gTSS 0 . The use of BOF slag also involved a low solubilisation of either nitrogen, carbon or phosphorous, a negligible mobilization of heavy metals and a positive effect on its biological hygienisation. A Class A biosolid for doses of 4.50gBOF/gTSS 0 or higher was achieved, which can be applied directly to the soil for agricultural purposes in accordance with current legislation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Characterizing the occurrence of organic contaminants (OCs) of environmental health concern in municipal sewage sludges is essential for safe handling and disposal of these abundant materials. This meta-analysis aimed to (i) summarize the extent of studies performed on the chemical composition of sewage sludges from China and the U.S., the world's two largest chemical producers, (ii) identify chemical groups of priority concern, (iii) quantitatively compare chemical abundance in sludge between nations, (iv) determine longitudinal contaminant accumulation trends in sludge, and (v) identify data gaps with regard to OC concentrations in sludge. A literature search was conducted on concentrations of OCs in U.S. sludges produced during treatment of domestic and industrial wastewater and compared statistically to contaminant levels in Chinese sludge abstracted from a recently established database. Longitudinal trends of OC occurrence were interpreted in the context of national chemical production, usage statistics, and regulations. A total of 105 studies on OCs in U.S. sewage sludge were found, while a total of 159 had been found in China. Among 1175 OCs monitored for, 23% of all analytes had been monitored in both countries (n = 269), 41% (n = 480) in China only, and the remaining 36% (n = 426) in the U.S. only. On average, concentrations of OCs were 4.0 times higher in U.S. than in Chinese sewage sludge, with the highest detection being observed for alkylphenol ethoxylates. Data from a new binational database on toxic OCs in sewage sludges suggest and reiterates the need for additional chemical monitoring in both countries, risk assessments for emerging OCs contained in sludges destined for application on land, and stronger enforcement of sludge disposal restrictions in China, where as much as 40% of sludge is currently being dumped improperly., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dr. Halden and Mr. Steele are co-founders of AquaVitas LLC, an Arizona State University startup company that works in the intellectual space touched upon by this study. Dr. Halden is founder of Arizona State University Foundation's OneWaterOneHealth, a nonprofit project providing wastewater-based health assessments to underserved US communities., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Environmental regulation of organic pollutants has not kept pace with the growth in the number and diversity of legacy and emerging organic substances now in use. Simpler and cheaper tools and methodologies are needed to quickly assess the organic pollutant risks in waste materials applied to land such as municipal wastewater treatment sludges and biosolids. This study attempts to provide these, using an approach that consists of chemical leaching and analysis of dissolved organic carbon and determination of its biodegradability by measuring persistent dissolved organic carbon. Primary and secondary sludges, dewatered sludge cake, and anaerobically and thermally treated biosolids obtained from various types of municipal wastewater treatment plants were used in the study. The study found little variability in the levels of dissolved organic carbon leached from primary sludges obtained from different municipal wastewater treatment plants but found significant differences for secondary sludges based on levels of nitrification at the municipal wastewater treatment plants. As predicted treated biosolids leached less dissolved organic carbon than untreated dry sludges but had relatively higher proportions of persistent or poorly biodegradable dissolved organic carbon. Across all tested sludges and biosolids persistent dissolved organic carbon ranged from 14 to 39%, with biosolids that have undergone anaerobic digestion and thermal treatment more likely to contain greater relative proportion of persistent dissolved organic carbon than untreated sludges. The approach presented in this study will be useful in assessing the effectiveness of current and widely employed sludge treatment methods in reducing persistent organic pollutants in biosolids disposed on land., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Waste activated sludge (biosolids) treatment is intensely a major problem around the globe. Anaerobic treatment is indeed a fundamental and most popular approach to convert organic wastes into bioenergy, which could be used as a carbon-neutral renewable and clean energy thus eradicating pathogens and eliminating odor. Due to the sheer intricate biosolid matrix (such as exopolymeric substances) and rigid cell structure, hydrolysis becomes a rate-limiting phase. Numerous different pretreatment strategies were proposed to hasten this rate-limiting hydrolysis and enhance the productivity of anaerobic digestion. This study discusses an overview of previous scientific advances in pretreatment options for enhancing biogas production. In addition, the limitations addressed along with the effects of inhibitors in biosolids towards biogas production and strategies to overcome discussed. This review elaborated the cost analysis of various pretreatment methods towards the scale-up process. This review abridges the existing research on augmenting AD efficacy by recognizing the associated knowledge gaps and suggesting future research., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA transmission route was thoroughly investigated in the hospital wastewater, sewage collection network, and wastewater treatment plants. Samples were taken on four occasions from December 2020 to April 2021. The performance of two different wastewater treatment processes of sequencing batch reactor (SBR) and conventional activated sludge (CAS) was studied for virus destruction. For this purpose, liquid phase, solid phase and bioaerosol samples were taken from different units of the investigated wastewater treatment plants (WWTPs). The results revealed that all untreated hospital wastewater samples were positive for SARS-CoV-2 RNA. The virus detection frequency increased when the number of hospitalized cases increased. Detection of viral RNA in the wastewater collection system exhibited higher load of virus in the generated wastewater in areas with poor socioeconomic conditions. Virus detection in the emitted bioaerosols in WWTPs showed that bioaerosols released from CAS with surface aeration contains SARS-CoV-2 RNA posing a potential threat to the working staff of the WWTPs. However, no viral RNA was detected in the bioaerosols of the SBR with diffused aeration system. Investigation of SARS-CoV-2 RNA in WWTPs showed high affinity of the virus to be accumulated in biosolids rather than transporting via liquid phase. Following the fate of virus in sludge revealed that it is completely destructed in anaerobic sludge treatment process. Therefore, based on the results of the present study, it can be concluded that receiving water resources could not be contaminated with virus, if the wastewater treatment processes work properly., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest associated with this study., (Copyright © 2021 Elsevier B.V. All rights reserved.)

This research compared the impact of two primary treatment options (i.e. primary clarification and rotating belt filtration (RBF)) on biological nutrients removal (BNR) process, using sludge fermentation liquid (SFL) as a carbon source. The liquid fraction of both fermented primary and RBF sludges comparably enhanced BNR. Despite the significant contribution of the unpurified SFL to the sharp increase in nutrient levels; i.e. 47%-64% (primary effluent; PE), and 45%-53% (RBF) of the soluble nitrogen and phosphorus loads; readily biodegradable COD and volatile fatty acids (VFAs) fractions of the combined feed increased significantly (2.5-6.1 times), compared to the original feed by additional SFL. Removal efficiencies in the reactors reached 57% (total nitrogen) and 92% (total phosphorus) after addition of SFL. Effluent nitrogen and phosphorus of the two reactors were close in the range of 15 ± 6 mg N/L, and 0.5 ± 0.3 mg P/L, respectively. Kinetics studies showed denitrification rates of 1.3, and 1.13 kg NO 3 -N/m 3 .d for primary effluent and RBF effluent-fed reactors, respectively. Phosphorus release rates were 11.7 and 9.7 mg PO 4 -P/g VSS.h, for primary, and RBF effluents, respectively; showing 20%-22% lower rates in the RBF SFL. Incorporating experimental data into a plant-wide model for a 100 MLD facility receiving typical medium strength wastewater, showed that although primary treatment enhanced the biogas production by 96% (primary clarification) and 62% (RBF) trains; combined fermentation and anaerobic digestion was effective to enhance the biogas production by 59% on average, compared to the base scenario without primary treatment. Additionally, if primary clarification exists, then the addition of fermentation results in additional revenue of C$1890/d in the plant, considering additional revenue of C$2230/d due to VFA generation in contrast to only C$340/d loss due to the reduced methane production., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Sewage sludge biochar (SSB) is a multi-nutrient fertilizer with very low K concentration. This study presents a novel K-enriched SSB fertilizer with the potential to increase K use efficiency by crops. The object of this work was therefore to evaluate the physical-chemical, morphological and mineralogical characteristics of a SSB organomineral fertilizer (OSSB) enriched with K. SSB was enriched with KCl and K 2 SO 4 using three technological methods (granules, pellets and powders). The enrichment of SSB with K ensured a K 2 O content about 75 times higher than the pure SSB. Organominerals in powder form had higher levels of total nitrogen, calcium, sulfur, phosphorus and higher pH than granules and pellets. The morphology and physical characteristics of enriched OSSBs were more influenced by the form of the fertilizer than by the source of K. In general, the enriched OSSBs are influenced by the quantities of feedstocks and the enrichment technology., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

This study evaluated the impact of ammonia on mesophilic anaerobic digestion (AD) with thermal hydrolysis pretreatment (THP) treating a mixture of primary sludge and waste activated sludge and operated under constant organic loading rate of 9 kg COD/m 3 /d. Free ammonia concentrations in the digesters were varied between 37 and 966 mg NH 3 -N/L, while maintaining all other operational conditions constant. A decrease in volatile solids reduction from 54 ± 5% (at <554 mg NH 3 -N/L) to 35 ± 6% at the maximum free ammonia concentration of 966 mg NH 3 -N/L was observed at steady-state conditions. No impact of free ammonia on final dewaterability was detected. Free ammonia thus mostly limited methanogenesis. A free ammonia Monod inhibition constant of 847 ± 222 mg NH 3 -N/L for methanogens was estimated based on the digester steady-state methane rates dynamics. This study showed that current THP AD digesters (typically 110-260 mg NH 3 -N/L) operate under 12%-18% ammonia inhibition for methanogenesis. Operation under SRT of 15 days, about 2 times more than needed to retain methanogens, can compensate for lower methanogens rates and avoid performance impacts. The later shows a good potential to operate under higher free and total ammonia concentration without jeopardizing performance. PRACTITIONER POINTS: Only from a free ammonia concentration above 554 mg NH 3 -N/L, decreased volatile solids reduction and biogas yield were observed. A volatile solids reduction of 35 ± 6% at maximum free ammonia concentration of 966 mg NH 3 -N/L was still achieved. A Monod inhibition constant for methanogens of 847 ± 222 mg NH 3 -N/L was estimated. It was estimated that current THP AD systems (110-260 mg NH 3 -N/L) operate under 12%-18% NH 3 inhibition for methanogenesis., (© 2021 Water Environment Federation.)

Plastics are ubiquitous contaminants that leak into the environment from multiple pathways including the use of treated sewage sludge (biosolids). Seven common plastics (polymers) were quantified in the solid fraction of archived biosolids samples from Australia and the United Kingdom from between 1950 and 2016. Six plastics were detected, with increasing concentrations observed over time for each plastic. Biosolids plastic concentrations correlated with plastic production estimates, implying a potential link between plastics production, consumption and leakage into the environment. Prior to the 1990s, the leakage of plastics into biosolids was limited except for polystyrene. Increased leakage was observed from the 1990s onwards; potentially driven by increased consumption of polyethylene, polyethylene terephthalate and polyvinyl chloride. We show that looking back in time along specific plastic pollution pathways may help unravel the potential sources of plastics leakage into the environment and provide quantitative evidence to support the development of source control interventions or regulations., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Phosphorus (P) is essential for all living things and an integral part of food production. However, significant amounts of P are functionally lost when wastewater byproducts, such as biosolids or sewage sludge incinerator ash (SSA), are not beneficially reused. Around 20% of sewage sludge produced in the US is incinerated and nearly 25% of sewage sludge is incinerated in European Union member countries. SSA contains significant amounts of P (up to 14% total P) and other beneficial elements but is typically sent to landfills for disposal. However, SSA has also been explored as one method of capturing and redirecting P back into the food system. Research investigating SSA characterization, P availability, and contaminant concentrations and behavior in soil is required to understand the effects of SSA land application on soil chemical properties and crop production. Several approaches for recovering P from SSA have been investigated that consider these factors. Ultimately, the opportunity for land application of SSA depends on the individual characteristics of a given SSA, ex. total P and contaminant concentrations, and the requirements and regulations of the region where it is produced and applied. In this review, we address the history of P recovery from SSA and discuss research regarding characterization, contaminants, P availability, and land application of SSA., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

In this study, municipal sewage sludge (MSS) is converted simultaneously into renewable biofuels (bio-oil, syngas) and high value-added products (biochar) using a fixed bed pyrolyzer. This work examines the combined effect of two factors: final pyrolysis temperature (°C) and MSS moisture content (%) on pyrogenic product yields and characteristics. A centered composite experimental design (CCD) is established for pyrolysis process optimization by adopting the response surface methodology (RSM). The statistical results indicate that the optimal conditions considering all studied factors and responses are 550 °C as final pyrolysis temperature and 15% as MSS moisture content. In these optimal conditions, biofuels yield is around 48 wt%, whereas biochar yield is about 52 wt%. The pyrolysis products characterizations reveal that (i) pyrolytic oil has a complex molecular composition rich with n-alkanes, n-alkenes, carboxylic acids, and aromatic compounds; (ii) bio-oil presents a high-energy content (high heating value HHV around 30.6 MJ/kg); (iii) syngas mixture has a good calorific value (HHV up to 8 MJ/kg), which could be used as renewable energy vector or for pyrolysis reactor heating; and (iv) biochar residue has good aliphatic and oxygenated group contents favoring its application as biofertilizer. These findings suggest that MSS conversion into biofuels and biochar is an appropriate approach for MSS treatment. MSS-to-energy could be proposed as an element for circular economy concept due to its effectiveness in producing high value-added and sustainable products and reducing environmental problems linked to MSS disposal.

E. coli survival in biosolids storage may present a risk of non-compliance with guidelines designed to ensure a quality product safe for agricultural use. The storage environment may affect E. coli survival but presently, storage characteristics are not well profiled. Typically biosolids storage environments are not actively controlled or monitored to support increased product quality or improved microbial compliance. This two-phased study aimed to identify the environmental factors that control bacterial concentrations through a long term, controlled monitoring study (phase 1) and a field-scale demonstration trial modifying precursors to bacterial growth (phase 2). Digested and dewatered biosolids were stored in operational-scale stockpiles to elucidate factors controlling E. coli dynamics. E. coli concentrations, stockpile dry solids, temperature, redox and ambient weather data were monitored. Results from ANCOVA analysis showed statistically significant (p < 0.05) E. coli reductions across storage periods with greater die-off in summer months. Stockpile temperature had a statistically significant effect on E. coli survival. A 4.5 Log reduction was measured in summer (maximum temperature 31 °C). In the phase 2 modification trials, covered stockpiles were able to maintain a temperature >25 °C for a 28 day period and achieved a 3.7 Log E. coli reduction. In winter months E. coli suppression was limited with concentrations >6 Log 10 CFU g -1 DS maintained. The ANCOVA analysis has identified the significant role that physical environmental factors, such as stockpile temperature, has on E. coli dynamics and the opportunities for control., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Agricultural use is the main way of recycling sewage sludge. Besides providing nutrients and organic matter to crops and soils, it is an important alternative for recycling this residue. However, problems during the sewage treatment process may generate sludge batches with an acidic pH. Thus, it is essential to understand the consequences of using such sludge on soils and plants, and to explore ways to overcome this limitation. The objective of this study was to evaluate addition rates of anaerobic sewage sludge (ASS) with acidic compositions on the soil fertility and performance of lettuce plants. Additionally, a methodology for pH correction of ASS with acidic pH is proposed. An agronomic experiment was conducted in a greenhouse using seven addition rates of ASS (0.0, 0.25, 0.5, 1, 2, 4 and 8 g kg -1 in dry basis), treated with an additional step of disinfection (solarization), and applied in an Albaqualf soil cultivated with lettuce (Lactuca sativa). Soil and leaf chemical composition, as well as chlorophyll index and the dry matter of lettuce leaves were evaluated. Failures during the acidogenesis phase of the anaerobic digestion process were probably the cause of ASS acidification. Although this ASS increased soil fertility indicators and plant dry matter, it significantly reduced soil pH, thereby requiring a complementary assay to correct its pH up to 6.0, which was achieved through liming. Anaerobic sewage sludges with an acidic pH can be effectively used in agriculture after being dried and disinfected through solarization, followed by pH correction, avoiding negative impacts on soil chemical attributes and plant response., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Highly persistent, toxic and bioaccumulative per - and polyfluoroalkyl substances (PFAS) represents a serious problem for the environment and their concentrations and fate remain largely unknown. The present study consists of a PFAS screening in sludges originating from 43 wastewater treatment plants (WWTPs) in the Czech Republic. To analyze an extended group of PFAS consisting of 32 PFAS, including GenX and other new replacements of older and restricted PFAS in sludge, a new method was optimized and validated using pressurized solvent extraction, followed by the SPE clean-up step to eliminate the observed matrix effects and LC-MS/MS. The results revealed high PFAS contamination of sewage sludge, reaching values from 5.6 to 963.2 ng g -1 . The results showed that in the majority of the samples (about 60%), PFOS was the most abundant among the targeted PFAS, reaching 932.9 ng g -1 . Approximately 20% of the analyzed samples contained more short-chain PFAS, suggesting the replacement of long-chain PFAS (especially restricted PFOA and PFOS). GenX was detected in 9 samples, confirming the trend in the use of new PFAS. The results revealed that significantly higher contamination was detected in the samples from large WWTPs (population equivalent > 50,000; p-value <0.05). Concerning the application of sludge in agriculture, our prediction using the respective PFAS bioconcentration factors, the observed concentrations, and the legislatively permitted management of biosolids in Czech Republic agriculture revealed that PFAS can cause serious contamination of cereals and vegetables (oat, celery shoots and lettuce leaves), as well as general secondary contamination of the environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Advancements in the field of residuals, sludge, and biosolids have been made in 2019. This review outlines the major contributions of researchers that have been published in peer-reviewed journals and conference proceedings throughout 2019 and includes brief summaries from over 125 articles. The review is organized in sections including life cycle and risk assessments; characteristics, quality, and measurement including micropollutants, nanoparticles, pathogens, and metals; sludge treatment technologies including dewatering, digestion, composting, and wetlands; disposal and reuse including adsorbents, land application and agricultural uses, nutrient recovery, and innovative uses; odor and air emissions; and energy issues., (© 2020 Water Environment Federation.)

U.S. municipal wastewater contains approximately 160 trillion Btu/y of influent chemical energy, but very little is recovered and utilized nationwide. Hydrothermal liquefaction (HTL) is a thermochemical process that converts biomass into a biocrude intermediate that can be upgraded to a variety of liquid fuels. HTL provides an opportunity to enhance energy recovery at wastewater treatment plants by transforming underutilized municipal wastewater solids into a renewable, cost-effective feedstock for transportation biofuels. In this study, we estimate total national economic sludge feedstock supply by performing discounted cash flow analyses at >15,000 U.S. wastewater treatment facilities to assess the net present value of 30-year HTL investments, with comparison to wider adoption of anaerobic digestion (AD). This analysis is the first to model HTL technology deployment across the real-world fleet of wastewater treatment plants. Analyses indicate treatment facilities ≥17 ML/d (4.6 million gal/d) could supply 9.77 Tg/y of dry solids feedstock to economically produce 3.67 GL/y of biocrude intermediate, thereby increasing energy, environmental, and financial sustainability of sludge treatment while reducing disposal costs and operational and environmental risk., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Sludge recycling as an agricultural resource has gained great attention worldwide. This is exacerbated by the ever-rising municipal wastewater production and the realization of its potential as a soil amendment resource. Sludge suitability assessment and characterization is crucial to prompt informed decisions regarding its use on agricultural lands. Liquid sludge samples were collected from eighteen wastewater treatment plants (WWTPs) employing three different treatment processes in South Africa. Samples were analysed for physical and chemical parameters. Sludges' pH ranged from 4.5-9.5. Heavy metals concentrations were below the threshold level except for two waste activated sludge (WAS) which were downgraded to class B due to high Lead (Pb) content. Two anaerobically digested (AnD) sludges were downgraded to classes B and C because of high Pb and Cadmium (Cd) concentrations respectively. Electrical conductivity (EC) was above the 200 mS m -1 threshold in AnD and in one of aerobically digested (AeD) sludges whilst WAS had ≤100 mS m -1 . Nitrogen (N): Phosphorus (P) ratios of the sludges were <8. Application of biosolids with low N:P ratio based on crop N requirements would lead to P pollution. Sustainable sludge application options were either to apply dry sludge based on crop N or P requirements and supplement the nutrient deficit with other fertilizer sources. The use of current liquid sludge as irrigation water to meet crop water needs and or applying dry sludge at 10 tons ha -1 options showed that such options are unsustainable and would add excess nutrients above crop need which would result in agroecosystems pollution. The study findings suggest that, supposedly these liquid sludges are used for irrigation, they should be diluted with fresh water or deficit irrigation should be implemented to limit nutrient load., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Sewage sludge generated by Waste Water Treatment Plants (WWTPs) are frequently used as organic amendments in agriculture, but they contain pollutants such as Potentially Toxic Elements (PTEs) and organic contaminants which contaminate the agricultural soils. The study presented here is part of a larger study based on the application of environmentally friendly chemical and biological techniques to decrease the content of organic pollutants in sewage sludge before agricultural application. The aim of this study was to evaluate the performance of biodegradable extractants, such as some cyclodextrins (CDs), β-cyclodextrin (BCD), hydroxypropyl-β-cyclodextrin (HPBCD) and randomly methylated-β-cyclodextrin (RAMEB), and a biosurfactant (rhamnolipid, RL) on the removal and availability of pyrene (PYR), phenanthrene (PHE) and nonylphenol (NP) from several biosolids samples in order to improve their subsequent biodegradation. The influence of pollutants retention time on biosolids was studied, as well as the effect of each extractant on PTEs solubilization. Results obtained were pollutant and extractant-dependent. BCD extracted similar amounts of pollutants compared to water, whereas HPBCD and RAMEB actually increased the availability of the three pollutants in most of the samples and aging times. RL seems to be the best election for Polycyclic Aromatic Hydrocarbons (PAHs) extraction from biosolids, with percentages of extraction multiplied by more than 80 and 40 times for PHE and PYR, respectively, relative to water extraction. The extraction enhancement was the highest for NP, the most hydrophobic pollutant, reaching more than 500-fold higher with HPBCD and RAMEB. PTEs extractability was not affected by the different CDs used, but RL caused an increment in their soluble content what could endanger a subsequent biodegradation of the organic pollutants., Competing Interests: Declaration of competing interest The authors of the manuscript entitled “Removal of nonylphenol, pyrene and phenanthrene from sewage sludge and biosolids by cyclodextrins and rhamnolipids” have no any financial and personal relationships with other people or organizations that could inappropriately influence (bias) our work., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Anaerobically digested biosolids (ABD) characteristics that affect dewatering were assessed at three water resource recovery facilities (WRRF) with different handling practices. Dewatering performance at the three sites corresponded to different levels of soluble chemical oxygen demand (COD), ammonia (NH 4 -N), and mono- and divalent cation concentrations in ADB. Capillary suction time (CST) and a modified centrifugal technique were used to determine optimum polymer doses and to assess the impact of handling conditions on dewatering performance. Both techniques indicated that polymer dosing between 15 and 20 kg/dry tonne was optimal for all facilities and that biosolids mixing and pumping did not significantly impact dewaterability. The CST values of anaerobically digested biosolids decreased as temperature increased, but no significant difference was found for either temperature or location of dewatering facilities. Sludge viscosity and rheological properties that vary with temperature appeared to have influenced CST values. Modified centrifugal technique results indicated cake solids were not affected by polymer make-up water or ADB temperature when emulsion polymer was used. This study shows the value of laboratory testing of biosolids under controlled conditions to identify and correct potential problems in full-scale operations. PRACTITIONER POINTS: Capillary suction time and a modified centrifugal technique were used to assess the impact of different process-related and environmental factors on dewatering. Higher concentrations of soluble COD (potentially extracellular polymeric substances - EPS) and low calcium (Ca) in anaerobically digested biosolids align with reduced dewaterability. Cell disruption and break down of floc structures due to storage/mixing and pumping of biosolids did not appear to negatively impact dewatering. Modified centrifugal test results did not provide conclusive evidence of whether dewatering of anaerobically digested biosolids could be significantly impacted by temperature over the range 15-30°C, especially when emulsion polymer is used. This study shows the value of laboratory testing of biosolids under controlled conditions to identify potential problems in the full-scale operations., (© 2019 Water Environment Federation.)

Solid or semisolid matrices polluted with fecal remnants can be highly loaded with pathogens, especially viruses, and play a substantial role in the persistence and dispersion of pathogens in the water cycle. Water quality regulations and guidelines are increasingly including bacteriophages infecting enteric bacteria as indicators of fecal and/or viral pollution. However, more data are needed about viral indicators in contaminated solids to develop effective sanitation strategies for the management of raw and treated sludge, fecal sludge, manures and slurries. Also, the exact role of sediments and soil in the transmission cycle of viral pathogens still needs to be determined. This review aims to provide an update on available data for concentrations of indicator bacteriophages in different solid matrices as well as their resistance to treatments and persistence in solids. The conclusion reached is that there is a need for improved and standardized methodologies for bacteriophage extraction, detection and enumeration in solids. Reports indicate that these contain higher levels of somatic coliphages in comparison with traditional bacterial indicators and F-specific RNA coliphages. Water body sediments and soil have been found to be notable reservoirs of somatic coliphages, which are more persistent in nature and resistant to sludge treatments than Escherichia coli and fecal coliforms and F-specific RNA coliphages. Thus, somatic coliphages show up as excellent complementary indicators for the prediction of pathogenic viruses in solids., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Sewage sludge is treated by means of cold plasma and stabilization in terms of biological load deactivation is achieved. The plasma is produced by floating electrode dielectric barrier discharge operating with air under atmospheric pressure conditions. The process is presented in detail and the discharge is characterized electrically. Additionally, simulation of the thermal flow inside the process chamber is implemented, using computational fluid dynamics. Deactivation of the serotypes S. Paratyphi B., S. Livingstone, S. Mbandaka and S. Typhimurium, and Escherichia coli and Coliforms, is hereby claimed. The process involves mean electrical power in the range of tens of watts, treatment time in the scale of minutes, and maximum instantaneous temperature <400 K. The present work is a preliminary contribution towards the promotion of advanced methods for the pro-ecological management of biosolids, according to European Regulations., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In this study, the disintegration potential of disperser coupled rhamnolipid (RLD) was investigated on pulp and paper mill secondary sedimentation tank (PPST) sludge. Initially, RLD dosage and pH were optimized for liquefied organic content release. Maximal of liquefied organic content release of 2158 mg/L was attained at an optimized RLD dosage (0.009 g/g TS (Total solids), pH 10). To augment liquefaction of PPST sludge further, disperser and disperser coupled RLD methods were carried out. Disperser coupled RLD method has achieved maximal liquefaction rate (27%) and total suspended solids (TSS) reduction (20%) at 5128 kJ/kg TS when compared to disperser method. Subsequently, methane assay was performed in which disperser coupled RLD method yielded higher methane production of 295 mL/g VS (Volatile solids). Then, cost analysis was performed in which disperser coupled RLD method achieved a net profit of 134 $/ ton of PPST sludge., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The present study aims to develop prediction models for estimating the potential uptake of 10 heavy metals (HMs) (cadmium, Cd; cobalt, Co; chromium, Cr; copper, Cu; iron, Fe; manganese, Mn; molybdenum, Mo; nickel, Ni; lead, Pb; zinc, Zn) by the tissues of Pisum sativum (root, shoot and pod) grown in soil amended with sewage sludge (SS) under greenhouse conditions. Soil organic matter (OM) was estimated by loss-on-ignition at 550 °C for 2 h. The pH was determined by shaking the soil and pure water at a 1:5 ratio. For HM quantifications, 0.5-1.0 g of each soil or plant sample was digested using a tri-acid mixture digestion method. The quantities of selected HMs were estimated by means of inductively coupled plasma optical emission spectrometry. Bio-concentration (BCF) and translocation (TF) factors were <1 for most of the HMs. In addition, simple linear correlations were significantly negative between the BCF of all studied HMs and soil pH, except for Pb, Mn and Ni, whereas significant positive correlations were observed between BCFs and soil OM, except for Mn, Ni and Zn. The accumulation of the 10 HMs in P. sativum tissues was predicted using regression models based on the values of the same HM in the soil as well as its pH and OM. The calculated prediction models performed well for most HMs in P. sativum tissues (except Ni in the pod, Cd in the shoot and Mn in the root). All measured soil factors (HM, pH and OM) consistently contributed to HM concentrations in the three tissues of the studied plants. These models may help to evaluate the safe cultivation of this species in soil amended with SS.

Cresols are chemical contaminants derivative from phenol which can be found in sewage sludge. However, little attention has been given to monitoring these compounds in environmental matrices in the literature. Thus, the objective of this study was to develop a simple method based on solid-liquid extraction with low temperature purification for determining three cresol isomers in sludge. The quantification of these compounds was performed by gas chromatography coupled to mass spectrometry with a previous derivatization step. After a detailed study, the cresol recovery was higher than 91%, with relative standard deviation lower than 12% and a limit of quantification of 20 μg kg -1 . Linearity was achieved between 10 and 90 μg L -1 ( R > 0.98) with the standard solutions prepared in matrix extracts due to the trouble caused by the matrix effect. The proposed method was applied with success for monitoring cresols in sewage sludge samples coming from six different wastewater treatment plants. All samples showed contamination by cresols, mainly 2 > 0.98) with the standard solutions prepared in matrix extracts due to the trouble caused by the matrix effect. The proposed method was applied with success for monitoring cresols in sewage sludge samples coming from six different wastewater treatment plants. All samples showed contamination by cresols, mainly p -cresol with values between 32.3 and 516.9 μg kg -1 . The majority of the analyzed samples showed a total sum of the isomers higher than the maximum residue limit established by Brazilian legislation (160 μg kg -1 ).

The advancements in the field of sludge and biosolids have been made over the past year. This review outlines the major contributions of researchers that have been published in peer-reviewed journals and conference proceedings throughout 2018. The review is organized in sections including regulatory developments and market analysis; analysis and quantification of characteristics including microconstituents and metals; treatment advances for the conversion of sludge to biosolids including pretreatment and sludge minimization, conditioning and dewatering, digestion, composting, and innovative technologies; product development and reuse including adsorbents and thermal products, agricultural and other uses, and innovative uses; odor and air emissions; and energy factors. PRACTITIONER POINTS: Summary of advances in the field of residuals and biosolids research in 2018. This review outlines the major contributions of researchers that have been published in peer-reviewed journals and conference proceedings. Topics covered range from regulation to innovation., (© 2019 Water Environment Federation.)

High-solids anaerobic co-digestion (HS-AcD) has the potential to recover energy and reduce environmental impacts of the organic fraction of municipal solid waste and waste activated sludge. We investigated the impact of substrate to inoculum (S/I) ratios, alkalinity sources (sodium bicarbonate and oyster shells), co-substrate mixing ratios and inoculum acclimation on HS-AcD of food waste, yard waste, and waste activated sludge using batch studies. Long-term HS-AcD performance was evaluated under the optimal conditions through a semi-continuous biodigester study with leachate recirculation. The digester with S/I = 1 using a mixture of crushed oyster shells and sodium bicarbonate as alkalinity sources had the highest methane yields (183 mL CH 4 /g VS). Addition of waste activated sludge to food waste and yard waste alleviated acidification (pH 6.86 ± 0.12) during the start-up period, which and improved digester stability. Mixtures with FW/YW/WAS = 0.8:1.7:0.5 had higher methane yields (134 ± 15 mL CH 4 /gVS) than mixtures with FW/YW/WAS = 1:1:1, but required a longer time (10 days) for self-recovery from volatile fatty acid inhibition. The use of an acclimated inoculum eliminated the lag time during start-up and produced 38% higher methane yield. In the semi-continuous biodigester, an average volatile solids reduction of 38% and methane yield of 186 mL/gVS was achieved. Improved performance in the semi-continuous biodigester compared with batch reactors was likely due to leachate recirculation, which can improve mass transfer of substrates to the microbial community. Digestate produced from HS-AcD of waste organics had a 1.7-2.3 fold higher nitrogen, similar phosphorous and 0.2-0.3 fold lower potassium content than commercially available bioorganic fertilizer., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The buffalo green monkey (BGM) cell line is required for the detection of enteric viruses in biosolids through a total culturable viral assay (TCVA) by the United States Environmental Protection Agency. In the present study, BGM and PLC/PRF/5 cell lines were evaluated for TCVA and for their use in determining the incidence of adenoviruses and enteroviruses in raw sludge and Class B biosolids. Six raw sludge and 17 Class B biosolid samples were collected from 13 wastewater treatment plants from seven U.S. states. Samples were processed via organic flocculation and concentrate volumes equivalent to 4 g total solids were assayed on BGM and PLC/PRF/5 cells. Cell monolayers were observed for cytopathic effect (CPE) after two 14-days passages. Cell lysates were tested for the presence of adenoviruses and enteroviruses by PCR or RT-PCR. The PLC/PRF/5 cells detected more culturable viruses than the BGM cells by CPE (73.9% vs. 56.5%, respectively). 52% of the samples were positive for CPE using both cell lines. No viruses were detected in either cell line by PCR in flasks in which CPE was not observed. No adenoviruses were detected in 13 CPE-positive samples from BGM lysates. In contrast, of the 17 samples exhibiting CPE on PLC/PRF/5 cells, 14 were positive for adenoviruses (82.4%). In conclusion, PLC/PRF/5 cells were superior for the detection of adenoviruses in both raw sludge and Class B biosolids. Thus, the use of BGM cells alone for TCVA may underestimate the viral concentration in sludge/biosolid samples.

Ten infrequently monitored antibiotics in biosolids were examined in archived American sewage sludges (n = 79) collected as part of the 2006/2007 U.S. Environmental Protection Agency (EPA) Targeted National Sewage Sludge Survey. This study inspected the occurrence of amoxicillin, ampicillin, erythromycin, furazolidone [proxy metabolite: 3-(2-nitrobenzylidenamino)-2-oxazolidinone (NP-AOZ)], nalidixic acid, oxolinic acid, oxytetracycline, spiramycin, sulfadimidine, and sulfadimethoxine in sewage sludges after nearly a decade in frozen storage. Six antibiotics were detected at the following average concentrations (ng/g dry weight): amoxicillin (1.0), nalidixic acid (19.1), oxolinic acid (2.7), erythromycin (0.6), oxytetracycline (4.5), and ampicillin (14.8). The remaining four were not detected in any samples (

The reuse of digested sludge from wastewater treatment plants (WWTPs) as soil fertilizer poses a risk for contamination of soil and water environments. The present study provides a new approach for investigating the exposure of hydrophobic organic chemicals in sewage sludge. The methodology of equilibrium sampling with multiple thicknesses of silicone was successfully validated and applied to complex sludge matrices. Polycyclic aromatic hydrocarbon (PAH) concentrations in silicone (C silicone ) were determined and compared across four WWTPs. Activity ratios (ARs), defined as C silicone at equilibrium with digested sludge (final product) over C silicone at equilibrium with secondary sludge (intermediate product), were in the range 0.85-20 with all except one AR>1. These ARs thus revealed increased thermodynamic potential of both parent and alkylated PAHs in digested sludge compared with secondary sludge, and thereby higher exposure of PAHs in sludge after digestion than before digestion. This observation can be explained by the concept of "solvent depletion" as organic matter decreased by a factor of 1.3 during digestion, resulting in reduced sorptive capacity and increased freely dissolved concentrations (C free ). The PAHs with logK ow > 6 had ARs close to 1.3, whereas PAHs with logK ow < 6 showed higher ARs than the organic matter decrease factor of 1.3. C free in digested sludge were higher than reported in rural soil and generally consistent with levels reported for Baltic Sea sediment., (Copyright © 2018 Elsevier Ltd. All rights reserved.)