Search

Laboratory waste that is disposed of into the environment will have an impact on environmental pollution and threaten human health. Efforts to treat laboratory wastewater must be carried out. This research aimed to analyze the effectiveness of Anaerobic Bioaccumulation Systems with sulfate-reducing bacteria (SRB) in reducing heavy metals and sulfate ions as well as the effectiveness of plant biofiltration (PB) in reducing biological oxygen demand (BOD), chemical oxygen demand (COD) and heavy metals in laboratory wastewater compared to quality standards. In this research, a plant biosystem which uses the principle of phytoremediation was used to reduce the heavy metal content in wastewater. This anaerobic reactor is cylindrical with r of 0.23 m and t of 0.93 m and has a volume of 1.5 m³. In this tank, there is an SRB initial growth column with a volume 6.7 L. SRB media in the form of 30% compost fermentation solution, Postgate B nutrients with 10% sulfate added to the column. It stimulated with SRB seeds that had been isolated previously, then laboratory waste is added until it fills the column. After being acclimatized for 15 days, the laboratory wastewater began to flow slowly into anaerobic bioaccumulation system. The next stage was a plant filtration system in a size of basin 3.0x1.0x1.0 m with of 4 vertical layers. The bottom layer consists of 20% limestone, 30% coral and 50% sand. The plant used was Sansevieria trifasciata. The research results showed that the SRB Anaerobic Bioaccumulation was effective in reducing heavy metals and sulfate ions by up to 80.6% with a residence time of 24 hours after growing SRB for 15 days PB is effective in reducing BOD, COD and heavy metal content to meet the specified quality standards with a residence time of 30 hours after plant acclimatization for 15 days. The combination of the SRB anaerobic accumulation and PB system worked effectively with a total residence time of 2.25 days, which was marked by a decrease in all test parameters to below the specified quality standards. [ABSTRACT FROM AUTHOR]

This paper presents reclamation of greywater using "Green-wall treatment system". A Green-wall of capacity 100 L/d has been implemented with the aim of greywater reclamation from a bathing water facility. The treatment system comprised of a degreasing tank of size 0.9 m x 0.9 m x 0.3 m for oil & grease removal, followed by a Green-wall. Removal of oil & grease has been done along with commonly observed pollutants in greywater, to prevent clogging of filler material. In stage-I studies, Green-wall pots are filled with 4-10 mm Ø inert filler material LECA and in stage-II, LECA is mixed with locally available coconut peat in equal proportion. Stage-I studies using LECA indicated that maximum achievable HRT is 12 h and the treated greywater with respect to BOD does not comply with USEPA (2012) norms for landscape irrigation. In stage-II, the optimized performance is observed at 16 &18 h HRT at hydraulic loading rate 67-70 L/m²/d, when compared with 14 and 12 h HRT. Treated greywater quality met the prescribed permissible limits with respect to BOD, TSS and FC and is observed to be innocuous in terms of the reuse options for agriculture and landscape irrigation. In stage-II, the BOD, COD, TSS and FC reduce from 48 to 10 mg/L, 58 to 18 mg/L, 96 to 10 mg/L and 400 CFU/ 100 mL to below detectable limits, respectively, at 18 h HRT. [ABSTRACT FROM AUTHOR]

This study aimed to compare the performance of biofiltration, constructed wetland, and constructed wetland microbial fuel cell (CW-MFC). The transformation from a biofiltration unit to a hybrid CW-MFC was demonstrated with the advantages of improvement of wastewater treatment while generating electricity simultaneously. The introduction of plants to the upper region of the bioreactor enhanced the DO level by 0.8 mg/L, ammonium removal by 5 %, and COD removal by 1 %. The integration of electrodes and external circuits stimulated the degradation rate of organic matter in the anodic region (1 % without aeration and 3 % with aeration) and produced 5.13 mW/m3 of maximum power density. Artificial aeration improved the nitrification efficiency by 38 % and further removed the residual COD to an efficiency of 99 %. The maximum power density was also increased by 3.2 times (16.71 mW/m3) with the aid of aeration. In treating higher organic loading wastewater (3M), the maximum power density showed a significant increment to 78.01 mW/m3 (4.6-fold) and the COD removal efficiency was 98 %. The ohmic overpotential dominated the proportion of total loss (67-91 %), which could be ascribed to the low ionic conductivity. The reduction in activation and concentration loss contributed to the lower internal resistance with the additional aeration and higher organic loading. Overall, the transformation from biofiltration to a hybrid CW-MFC system is worthwhile since the systems quite resemble while CW-MFC could improve the wastewater treatment as well as recover energy from the treated wastewater. [ABSTRACT FROM AUTHOR]

The rapid development of aquaculture makes it desirable to use environment-friendly methods of purifying the wastewater effluent. Seaweed is often cultured for the dual purpose of useful algal biomass production and its bioremediation potential. This paper offers a survey on growth characters and ecological functions of the macroalgae Gracilaria gracilis (Steentoft, L.M. Irvine & Farnham, 1995), collected from Ganzirri lagoon (Messina, Italy). The results obtained provided promising data in terms of growth rates, biomass and biofiltering potential of G. gracilis. A daily growth rate (DGR) of 0.70%/g and biomass 36,05 g/m3 was obtained using tanks with lower lighting. Its biofiltration efficiency was demonstrated by the strong correlation between the algal growth parameters (Y and DGR) and the concentration decrease of dissolved nutrients. Results provided in this study indicated that G. gracilis can find application in aquaculture systems as a biofilter and that biomass produced offers a valid resource for further biotechnological applications. [ABSTRACT FROM AUTHOR]

Background: The Mycobacterium tuberculosis complex (MTBC) consists of causative agents of both human and animal tuberculosis and is responsible for over 10 million annual infections globally. Infections occur mainly through airborne transmission, however, there are possible indirect transmissions through a faecal-oral route which is poorly reported. This faecal-oral transmission could be through the occurrence of the microbe in environments such as wastewater. This manuscript, therefore, reviews the source and fate of MTBC in the wastewater environment, including the current methods in use and the possible risks of infections.Results: The reviewed literature indicates that about 20% of patients with pulmonary TB may have extra-pulmonary manifestations such as GITB, resulting in shedding in feaces and urine. This could potentially be the reason for the detection of MTBC in wastewater. MTBC concentrations of up to 5.5 × 105 (±3.9 × 105) copies/L of untreated wastewater have been reported. Studies have indicated that wastewater may provide these bacteria with the required nutrients for their growth and could potentially result in environmental transmission. However, 98.6 (± 2.7) %, removal during wastewater treatment, through physical-chemical decantation (primary treatment) and biofiltration (secondary treatment) has been reported. Despite these reports, several studies observed the presence of MTBC in treated wastewater via both culture-dependent and molecular techniques.Conclusion: The detection of viable MTBC cells in either treated or untreated wastewater, highlights the potential risks of infection for wastewater workers and communities close to these wastewater treatment plants. The generation of aerosols during wastewater treatment could be the main route of transmission. Additionally, direct exposure to the wastewater containing MTBC could potentially contribute to indirect transmissions which may lead to pulmonary or extra-pulmonary infections. This calls for the implementation of risk reduction measures aimed at protecting the exposed populations. [ABSTRACT FROM AUTHOR]

The oil industry generates large volumes of liquid waste with high levels of contamination and its discharge into bodies of water causes the deterioration of the environment. In order to evaluate the biofiltration in a fixed bed with different natural materials, in the treatment of production waters of said activity, two biofilters packed with adsorbent materials and recirculation in discontinuous during 7 days of experimentation were evaluated. The ecotoxicity of the residue from each column was analyzed at the end of the experiment to evaluate its final disposition. The biofilters operated in a stable way guaranteeing a notable reduction of COD, sulphides, fats and oils. The residues were shown to be toxic, although a ratio of 5:25 g of residue: soil mixture can be used as a conditioner in the remediation of contaminated soils. [ABSTRACT FROM AUTHOR]

Biofiltration is a promising wastewater treatment green technology employed to remove various types of pollutants. The efficiency of biofiltration relies on biofilm, and its performance is significantly influenced by various factors such as dissolved oxygen concentration, organic loading rate, hydraulic retention time, temperature, and filter media selection. The existing biofilters utilize conventional media such as gravel, sand, anthracite, and many other composite materials. The material cost of these conventional filter materials is usually higher compared to using organic waste materials as the filter media. However, the utilization of organic materials as biofilter media has not been fully explored and their potential in terms of physicochemical properties to promote biofilm growth is lacking in the literature. Therefore, this review critically discusses the potential of shifting conventional filter media to that of organic in biofiltration wastewater treatment, focusing on filtration efficiency-influenced factors, their comparative filtration performance, advantages, and disadvantages, as well as challenges and prospective areas of organic biofilter development. [ABSTRACT FROM AUTHOR]

Due to the lower energy consumption and waste production compared to traditional methods, the environmental bioremediation methods based on natural processes have been gradually becoming more prevalent in environmental engineering. Biological methods are used in waste management, wastewater treatment, gas treatment or soil remediation. For the low solubility of some pollutants and lower bioavailability, the use of biological methods may be hampered. This problem might be mitigated with the use of surfactants. This paper presents the results of studies regarding the effect of dosing a selected surfactant from the Tween group (Tween 20) on the efficiency of toluene elimination from the air by biofiltration. The obtained maximum biofiltration rate was 21.2 g/m³/h and 19.8 g/m³/h for the control bed and for the bed to which the Tween 20 solution was dosed, respectively. The effect of Tween was neutral (the effectiveness of toluene removal was insignificantly comparable to the effectiveness of the control series), it did not affect the effectiveness or limited the development of the biofilter microflora. [ABSTRACT FROM AUTHOR]

Trimethylamine (TMA) is an odorous volatile organic compound emitted by industries. Algal-based biotechnologies have been proven as a feasible alternative for wastewater treatment, although their application to abate polluted air emissions is still scarce. This work comparatively assessed the removal of TMA in a conventional bacterial bubble column bioreactor (BC) and a novel algal-bacterial bubble column photobioreactor (PBC). The PBC exhibited a superior TMA abatement performance compared to the conventional BC. In this sense, the BC reached a removal efficiency (RE) and an elimination capacity (EC) of 78% and 12.1 g TMA m−3 h−1, respectively, while the PBC achieved a RE of 97% and a EC of 16.0 g TMA m−3·h−1 at an empty bed residence time (EBRT) of 2 min and a TMA concentration ~500 mg m−3. The outstanding performance of the PBC allowed to reduce the operating EBRT to 1.5 and 1 min while maintaining high REs of 98 and 94% and ECs of 21.2 and 28.1 g m−3·h−1, respectively. Moreover, the PBC improved the quality of the gas and liquid effluents discharged, showing a net CO2 consumption and decreasing by ~ 30% the total nitrogen concentration in the liquid effluent via biomass assimilation. A high specialization of the bacterial community was observed in the PBC, Mumia and Aquamicrobium sp. being the most abundant genus within the main phyla identified. [ABSTRACT FROM AUTHOR]

Biofiltration is one kind of common technology used for treating micro-polluted brackish aquaculture wastewater. Based on the characteristics of actual water quality, a novel two-stage biofiltration system was set up to reduce potential nutrient pollution brought by the frequent exchange of water in brackish pond aquaculture. Zeolite was selected as filtration media for the first stage and pyrite mixed with a small amount of sulfur for the second stage. Apart from the adsorption of nutrients exerted by these natural minerals, biofilm played a leading role in nutrient removal. The surface and internal pore of zeolite-sheltered nitrifiers and sulfur-containing compounds enhanced autotrophic denitrification. It was found that ammonia adsorption capacity of zeolite was reduced by nearly 58% when salinity was increased to 1.5%, while phosphate adsorption capacity of pyrite was hardly influenced and systematic hydraulic retention time (HRT) of 24 h was proven appropriate, 9.6 h and 14.4 h for the two stages, respectively. Meanwhile, removal efficiency of 96.5% for NH4+-N and 92.1% for total inorganic nitrogen (TIN) was achieved under this condition. The analysis of microbial community of biofilm indicated that dominant genera responsible for nitritation and nitration on the surface of zeolite were Nitrosomonas and Nitrospira, respectively. Dominant genera responsible for autotrophic denitrification on the surface of pyrite and sulfur were both Thiobacillus. In addition, Ferritrophicum, related to the iron-oxidizing bacterium, also coexisted due to biological oxidation of pyrite. Long-term operation verified applicability and stability of this two-stage biofiltration system for brackish aquaculture wastewater purification. [ABSTRACT FROM AUTHOR]

Biofiltration is a promising wastewater treatment green technology employed to remove various types of pollutants. The efficiency of biofiltration relies on biofilm, and its performance is significantly influenced by various factors such as dissolved oxygen concentration, organic loading rate, hydraulic retention time, temperature, and filter media selection. The existing biofilters utilize conventional media such as gravel, sand, anthracite, and many other composite materials. The material cost of these conventional filter materials is usually higher compared to using organic waste materials as the filter media. However, the utilization of organic materials as biofilter media has not been fully explored and their potential in terms of physicochemical properties to promote biofilm growth is lacking in the literature. Therefore, this review critically discusses the potential of shifting conventional filter media to that of organic in biofiltration wastewater treatment, focusing on filtration efficiency-influenced factors, their comparative filtration performance, advantages, and disadvantages, as well as challenges and prospective areas of organic biofilter development.

The main objective of wastewater treatment is to remove carbon and other nutrients from municipal and industrial effluents in order to protect the environment and human health. Typical wastewater treatment is usually achieved by a combination of physical, chemical and biological methods. In this work, municipal wastewater was depurated using chemically enhanced primary treatment (CEPT) in combination with a pilot-scale trickling filter. Lab scale experiments (Jar-tests) were carried out in order to determine the optimum dosage of chemicals. Selection criteria were the organic load removal efficiency and the low operational cost. Coagulation-flocculation process was conducted through polyaluminium chloride (PAC) and the cationic polyelectrolyte (Zetag 8180) addition. By combining CEPT and trickling filter, tCOD (total Chemical Oxygen Demand), sCOD (soluble Chemical Oxygen Demand), BOD5 (5-day Biochemical Oxygen Demand), NH4+-N, TSS (Total Suspended Solids), VSS (Volatile Suspended Solids) and PO43−-P removal efficiencies were estimated to be 89, 82, 93, 60, 96, 96 and 78%, respectively. It is concluded that biological filtration contributed significantly in nutrients removal processes. Moreover, the obtained effluent was low in carbon and rich in nitrogen, which can be applied for restricted irrigation after disinfection, complying with the discharge limits set in the Greek Joint Ministerial Decree 145116/2011. [ABSTRACT FROM AUTHOR]

The use of bioscrubber is attracting increasing attention for exhaust gas treatment in intensive pig farming. However, the challenge is to improve the methane (CH4) removal efficiency as well as the possibility of pig house wastewater treatment. Three laboratory-scale bioscrubbers, each equipped with different recirculation water types, livestock wastewater (10-times-diluted pig house wastewater supernatant), a methanotroph growth medium (10-times-diluted), and tap water, were established to evaluate the performance of CH4 removal and wastewater treatment. The results showed that enhanced CH4 removal efficiency (25%) can be rapidly achieved with improved methanotrophic activity due to extra nutrient support from the wastewater. The majority of the CH4 was removed in the middle to end part of the bioscrubbers, which indicated that CH4 removal could be potentially optimised by extending the length of the reactor. Moreover, 52–86% of the ammonium (NH4+-N), total organic carbon (TOC), and phosphate (PO43−-P) removal were simultaneously achieved with CH4 removal in the present study. Based on these results, this study introduces a low-cost and simple-to-operate method to improve CH4 removal and simultaneously treat pig farm wastewater in bioscrubbers. [ABSTRACT FROM AUTHOR]

The development and full-scale application of microbial electrochemical technologies (METs) for wastewater treatment demand massive amounts of electroconductive carbon materials to promote extracellular electron transfer (EET) and biodegradation. While the potential capability of these materials and their properties to design efficient systems is still in their infancy, the state-of-the-art METs are based on highly-conductive fossil-derived carbons. In this work we evaluate the performance of different electroconductive carbon materials (graphite, coke, biochar) for supporting microbial EET and treating urban wastewater. Our results reveal that the electroconductive biochar was the most efficient biofilter-material, enabling to stimulate bioremediation at anodic potential as high as 0.6 V (maximum removal efficiency (92%) and degradation rate (185 g-COD m−3d−1)), and to fulfill the discharge limits under conditions where the other materials failed. A deep materials characterization suggests that, despite electroconductivity is necessary, the optimal EET on biochar can be mainly assigned to its large number of electroactive surface oxygen functionalities, which can reversibly exchange electrons through the geobattery mechanism. We propose the modulation of quinone-like e-acceptors by anodic polarization to promote the biodegradation capability of carbon materials. Because of its great efficiency and sustainability, electroactive biochar will greatly expand the applicability of METs at large scale. Image 1 [ABSTRACT FROM AUTHOR]

Large volumes of water are required for the development of unconventional oil and gas (O&G) wells. Water scarcity coupled with seismicity induced by deep-well disposal promote new O&G wastewater management strategies, specifically treatment and reuse. One technology that has been proven effective for removal of organic matter and solids is biologically active filtration (BAF) with granular active carbon (GAC); however, further optimization is needed to enhance BAF performance. This study evaluated three GAC media (one spent and two new) and two nutrient-mix supplements for enhanced removal of chemical oxygen demand (COD) and dissolved organic carbon (DOC). Biofilm development was also monitored and correlated to BAF performance. The spent GAC with extant biofilm quickly acclimated to PW and demonstrated up to 92% DOC removal (81% COD) in 24 h, while little impact by nutrient addition was observed. In addition, virgin GAC was slow to establish a biofilm, indicating that appropriate GAC selection and pre-developed biofilm is critical for efficient BAF performance. Furthermore, the production of high quality BAF effluent (less than 20 mg/L DOC) presents the opportunity to apply BAF as a pretreatment for subsequent desalination—expanding the potential for reuse applications of PW. [ABSTRACT FROM AUTHOR]

Abstract Although granular activated carbon (GAC) has been broadly applied in ozone-biologically activated carbon filtration (O 3 /BAC) systems for potable reuse of municipal wastewater, the mechanisms of various pollutant removal remain largely unknown as the regenerated GAC develops microbial populations resulting in biofiltration but loses significant adsorption capacity as it becomes spent GAC. Therefore, pilot-scale parallel performance comparisons of spent and regenerated GAC, along with a range of pre-oxidant ozone doses, were used to shed light on the mechanisms responsible for the removal of various types of treatment byproduct precursors and trace organic compounds. It was confirmed from this pilot-study that ozone alone can effectively degrade chlorinated trihalomethane (THM) and haloacetic acid (HAA) precursors, chloramine-reactive N-nitrosodimethylamine (NDMA) precursors, and 29 PPCPs. In contrast, biodegradation by microbial population on spent or regenerated GAC can remove NDMA and 22 PPCPs, while the adsorption by regenerated GAC can remove chlorinated THM and HAA precursors, PFAS, flame retardants, and 27 PPCPs. The results of this pilot study are intended to provide those interested in potable reuse with an example of the simultaneous removal capabilities and mechanisms that can be anticipated for treating a complex mixture of organics present in real municipal wastewater effluent. Highlights • Roles of spent and regenerated GAC were for the first time compared. • Pathways for the removal of a wide spectrum of compounds were identified. • Biodegradation can remove NDMA and 22 PPCPs. • Adsorption can remove THM and HAA precursors, PFAS, flame retardants, and 27 PPCPs. • Ozone can remove THM, HAA, chloramine-reactive NDMA precursors, and 29 PPCPs. [ABSTRACT FROM AUTHOR]

Natural organic matter (NOM) is ubiquitous in the aquatic environment and if present can cause varied drinking water quality issues, the major one being disinfection byproduct (DBP) formation. Trihalomethanes (THMs) are major classes of DBP that are formed during chlorination of NOM. The best way to remove DBPs is to target the precursors (NOM) directly. The main aim of this review is to study conventional as well as advanced ways of treating NOM, with a broad focus on NOM removal using advanced oxidation processes (AOPs) and biofiltration. The first part of the paper focuses on THM formation and removal using conventional processes and the second part focuses on the studies carried out during the years 2000-2018, specifically on NOM removal using AOPs and AOP-biofiltration. Considering the proven carcinogenic nature of THMs and their diverse health effects, it becomes important for any drinking water treatment industry to ameliorate the current water treatment practices and focus on techniques like AOP or synergy of AOP-biofiltration which showed up to 50-60% NOM reduction. The use of AOP alone provides a cost barrier which can be compensated by the use of biofiltration along with AOP with low energy inputs, making it a technoeconomically feasible option for NOM removal. [ABSTRACT FROM AUTHOR]

Expansion of modern industry coupled with a lack of effective treatment systems has resulted in excessive release of toxic and odorous pollutants such as hydrogen sulfide (H 2 S). Development of treatment measures is therefore necessary to protect ecosystems and human health. This paper explores recent advances in H 2 S treatment technologies. Particular focus is placed on innovative and recent advances in biofiltration, especially for wastewater treatment facilities and biogas generation (e.g., use of innovative packing media for better performance and reduced pressure drop, eliminating sulfate accumulation, and development of modeling techniques). The review also identifies current challenges and future prospects (e.g., fluctuations in methane and carbon dioxide concentrations during biogas upgradation, optimizing anoxic H 2 S biofiltration, and understanding the effects of operating conditions on biofilter performance) for improving biofiltration by highlighting research gaps in related fields. [ABSTRACT FROM AUTHOR]

Microbial community structure in the ozone-biofiltration systems of two drinking water and two wastewater treatment facilities was characterized using 16S rRNA gene sequencing. Collectively, these datasets enabled comparisons by facility, water type (drinking water, wastewater), pre-oxidation (ozonation, chlorination), media type (anthracite, activated carbon), media depth, and backwash dynamics. Proteobacteria was the most abundant phylum in drinking water filters, whereas Bacteroidetes, Chloroflexi, Firmicutes, and Planctomycetes were differentially abundant in wastewater filters. A positive correlation was observed between media depth and relative abundance of Cyanobacteria in drinking water filters, but there was only a slight increase in one alpha diversity metric with depth in the wastewater filters. Media type had a significant effect on beta but not alpha diversity in drinking water and wastewater filters. Pre-ozonation caused a significant decrease in alpha diversity in the wastewater filters, but the effect on beta diversity was not statistically significant. An evaluation of backwash dynamics resulted in two notable observations: (1) endosymbionts such as Neochlamydia and Legionella increased in relative abundance following backwashing and (2) nitrogen-fixing Bradyrhizobium dominated the microbial community in wastewater filters operated with infrequent backwashing. Bradyrhizobium is known to generate extracellular polymeric substances (EPS), which may adversely impact biofilter performance and effluent water quality. These findings have important implications for public health and the operation and resiliency of biofiltration systems. [ABSTRACT FROM AUTHOR]

The use of gadolinium-based contrasting agents (GBCA) is increasing because of the intensive usage of these agents in magnetic resonance imaging (MRI). Waste-water treatment does not reduce anthropogenic Gd-concentration significantly. Anomalous Gd-concentration in surface waters have been reported worldwide. However, removal of GBCA-s by aquatic macrophytes has still hardly been investigated. Four aquatic plant species ( Lemna gibba , Ceratophyllum demersum , Elodea nuttallii , E. canadensis ) were investigated as potential biological filters for removal of commonly used but structurally different GBCA-s (Omniscan, Dotarem) from water. These plant species are known to accumulate heavy metals and are used for removing pollutants in constructed wetlands. The Gd uptake and release of the plants was examined under laboratory conditions. Concentration-dependent infiltration of Gd into the body of the macrophytes was measured, however significant bioaccumulation was not observed. The tissue concentration of Gd reached its maximum value between day one and four in L. gibba and C. demersum , respectively, and its volume was significantly higher in C. demersum than in L. gibba . In C. demersum , the open-chain ligand Omniscan causes two-times higher tissue Gd concentration than the macrocyclic ligand Dotarem. Gadolinium was released from Gd-treated duckweeds into the water as they were grown further in Gd-free nutrient solution. Tissue Gd concentration dropped by 50% in duckweed treated by Omniscan and by Dotarem within 1.9 and 2.9 days respectively. None of the macrophytes had a significant impact on the Gd concentration of water in low and medium concentration levels (1–256 μg L −1 ). Biofiltration of GBCA-s by common macrophytes could not be detected in our experiments. Therefore it seems that in constructed wetlands, aquatic plants are not able to reduce the concentration of GBCA-s in the water. Furthermore there is a low risk that these plants cause the accumulation of anthropogenic Gd in the food chain. [ABSTRACT FROM AUTHOR]

Treated wastewater is a valuable resource, particularly in countries facing water shortage such as Jordan. Nevertheless, excess nutrients, especially phosphorus, may have detrimental impacts on receiving waterbodies. Treated wastewater in Jordan often exceeds the recommended levels set by the Jordanian Standards for wastewater reuse and discharge. Therefore, it is important to reduce phosphorus loads to acceptable levels before discharge. Biofiltration is a low-cost technology that has shown good potential for wastewater treatment. The performance of biofilters largely depends on the media used. In this study, local sand and sand augmented with biochar prepared from the olive oil processing waste (SBC) were used as filter media for phosphorus removal from clarified secondary treated wastewater. The two media types were tested under different hydraulic and phosphorus loading conditions to simulate shock, flooding, and inundation conditions. The results showed that sand media was more effective in removing phosphorus (90.8 ± 2.6%) than sand amended with biochar (83.3 ± 3.2%). Both media showed resilience under extreme loading conditions. Although phosphorus removal efficiency was negatively affected following the extreme loading events, the observed effects were temporary. The simulated inundation event further showed that the media was able to retain the adsorbed phosphorus. Furthermore, the phosphorus concentration in the effluent remained within the prescribed discharge guidelines at all times. [ABSTRACT FROM AUTHOR]

This study was focused on the application of an aerobic biofiltration (BF) with Ficus benjamina wood chips as support medium, inoculated with two basidiomycete fungi, Phanerochaete chrysosporium (BF 1) and Trametes versicolor (BF 2), to treat Tequila vinasses from a Tequila industry. The biofiltration system was compared with a biofilter system without basidiomycete fungi (BF W), in order to determine the influence of fungi on the treatment of vinasses. Three different vinasses/ water ratios (30/70, 40/60, and 50/50) were evaluated. The maximum removals of chemical oxygen demand (COD) obtained during each operation step were 72% (BF 1), 72% (BF 2), and 8% (BF W) for 30 vinasses/70 water; 72% (BF 1), 73% (BF 2), and 66% (BF W) for 40 vinasses/60 water; and 22% (BF 1), 20% (BF 2), and 18% (BF W) for 50 vinasses/50 water. The total organic carbon (TOC) removal was significantly increased using a volumetric organic load of 5.5 kg COD m-3 d-1. During the operation of the biofilters, the enzymatic activity of laccase was present, even at the step of highest concentration of vinasses. [ABSTRACT FROM AUTHOR]

Dissolved organic matter (DOM) present in oil and gas (O&G) produced water and fracturing flowback was characterized and quantified by multiple analytical techniques throughout a hybrid biological-physical treatment process. Quantitative and qualitative analysis of DOM by liquid chromatography – organic carbon detection (LC-OCD), liquid chromatography–high-resolution mass spectrometry (LC-HRMS), gas chromatography–mass spectrometry (GC–MS), and 3D fluorescence spectroscopy, demonstrated increasing removal of all groups of DOM throughout the treatment train, with most removal occurring during biological pretreatment and some subsequent removal achieved during membrane treatment. Parallel factor analysis (PARAFAC) further validated these results and identified five fluorescent components, including DOM described as humic acids, fulvic acids, proteins, and aromatics. Tryptophan-like compounds bound by complexation to humics/fulvics were most difficult to remove biologically, while aromatics (particularly low molecular weight neutrals) were more challenging to remove with membranes. Strong correlation among PARAFAC, LC-OCD, LC-HRMS, and GC–MS suggests that PARAFAC can be a quick, affordable, and accurate tool for evaluating the presence or removal of specific DOM groups in O&G wastewater. [ABSTRACT FROM AUTHOR]

Foul odors comprise generally a complex mixture of molecules, where reduced sulfur compounds play a key role due to their toxicity and low odor threshold. Previous reports on treating mixtures of sulfur compounds in single biofilters showed that hydrogen sulfide (H 2 S) interferes with the removal and degradation of other sulfur compounds. In this study, hydrogen sulfide (H 2 S) and dimethyl disulfide (DMDS) were fed to an alkaline biotrickling filter (ABTF) at pH 10, to evaluate the simultaneous removal of inorganic and organic sulfur compounds in a single, basic-pH system. The H 2 S-DMDS mixture was treated for more than 200 days, with a gas residence time of 40 s, attaining elimination capacities of 86 g DMDS m −3 h −1 and 17 g H2S m −3 h −1 and removal efficiencies close to 100%. Conversion of H 2 S and DMDS to sulfate was generally above 70%. Consumption of sulfide and formaldehyde was verified by respirometry, suggesting the coexistence of both methylotrophic and chemoautotrophic breakdown pathways by the immobilized alkaliphilic biomass. The molecular biology analysis showed that the long-term acclimation of the ABTF led to a great variety of bacteria, predominated by Thioalkalivibrio species, while fungal community was notoriously less diverse and dominated by Fusarium species. [ABSTRACT FROM AUTHOR]

A biofiltration system was developed to treat benzene, toluene, ethylbenzene, and xylene (BTEX) and Hg° vapour from a petrochemical waste stream during overhaul maintenance. The biofilter compost bed was inoculated with a microbial consortium provided by a petrochemical wastewater treatment plant. The effect of the a BTEX concentration (192.6–973.8 g/m 3 h) and empty bed residence time (EBRT) of 20–100 s were studied under the conditions of steady state, transient, shock BTEX-loading, and off-restart. The findings revealed that during a biofilter start-up, an increase in the influent BTEX concentration to around 334.3 g/m 3 h did not notably affect the biofiltration function at an EBRT of 100 s, and the removal efficiency was higher than 98%. Further, the low EBRT of 60 s did not have adverse effects on the BTEX and Hg° biofiltration (the removal efficiency in both was >93%). For the biofiltration system, the BTEX and Hg° critical attenuation capacity were obtained as 663 g BTEX /m 3 h and 12.6 g Hg° /m 3 h respectively. A maximum attenuation capacity of 774.5 g BTEX /m 3 h was achieved in the biofilter when the BTEX loading rate was 973.8 g BTEX /m 3 h. The parameters of k m and r max of the Michaelis–Menten kinetic model were obtained as 0.099 g/m 3 and 0.578 g/m 3 min respectively. Both BTEX and mercury vapours were completely mass balanced during a continuous biofiltration test. In general, the developed treatment system exhibited a good performance in the treatment of the BTEX stream containing Hg° vapour in the off-gas of a petrochemical company. [ABSTRACT FROM AUTHOR]

The use of biochar as a filter medium amendment has shown potential for removing organic and inorganic pollutants from wastewater. The purpose of this study was to investigate the effect of biochar particle size on: (i) removal efficiency of total phosphorus (TP) from wastewater; (ii) stability of the system under overloading and flooding conditions; and (iii) desorption potential of phosphorus from the filtration medium under inundation conditions. Biochar was prepared in two different sizes: fine and coarse with a mean diameter size of 0.31 and 0.49 mm, respectively. Two treatments using sand augmented with 8% by weight fine biochar (sand-FBC) and sand augmented with 8% by weight coarse biochar (sand-CBC) were tested. The TP removal efficiency of sand-CBC was 10% higher than sand-FBC medium. The average removal efficiencies were 83.3 ± 3.2 and 75.7 ± 7.4% for sand-CBC and sand-FBC media, respectively. Positive correlations between TP load and removal efficiencies were observed. All treatments showed resilience to overloading, flooding, and inundation conditions. [ABSTRACT FROM AUTHOR]

Due to the shortening on natural water resources, reclaimed wastewater will be an important water supply source. However, suitable technologies must be available to guaranty its proper detoxification with special concern for the emerging pharmaceutical and personal care products that are continuously reaching municipal wastewater treatment plants. While conventional biological systems are not suitable to remove these compounds, ozone, due to its interesting features involving molecular ozone oxidation and the possibility of generating unselective hydroxyl radicals, has a wider range of action on micropollutants removal and water disinfection. This paper aims to review the studies dealing with ozone based processes for water reuse by considering municipal wastewater reclamation as well as natural and drinking water treatment. A comparison with alternative technologies is given. The main drawback of ozonation is related with the low mineralization achieved that may lead to the production of reaction intermediates with toxic features. The use of hydrogen peroxide and light aided systems enhance ozone action over pollutants. Moreover, scientific community is focused on the development of solid catalysts able to improve the mineralization level achieved by ozone. Special interest is now being given to solar light catalytic ozonation systems with interesting results both for chemical and biological contaminants abatement. Nowadays the integration between ozonation and sand biofiltration seems to be the most interesting cost effective methodology for water treatment. However, further studies must be performed to optimize this system by understanding the biofiltration mechanisms. [ABSTRACT FROM AUTHOR]

Greywater is being increasingly used as an alternative water source to reduce potable water demand and to alleviate pressure on sewerage systems. This paper presents the development of a low energy and low maintenance greywater treatment technology: a living wall system, employing ornamental plants (including vines) grown in a sand filter on a side of a building to treat shower, bath, and washing basin wastewaters. The system can, at the same time, provide critical amenity and micro-climate benefits to our cities. A large scale column study was conducted in Melbourne, Australia, to investigate the following design and operational factors of the proposed system: plant species, saturated zone design, rest period, hydraulic loading rate and pollutant inflow concentration. The results indicate that the use of ornamental species (e.g. Canna lilies , Lonicera japonica , ornamental grape vine) can contribute to pollutant removal. Vegetation selection was found to be particularly important for nutrient removal. While a wider range of tested plant species was effective for nitrogen removal (>80%), phosphorus removal was more variable (−13% to 99%) over the study period, with only a few tested plants being effective - Carex appressa and Canna lilies were the best performers. It was also found that phosphorus removal can be compromised over the longer term as a result of leaching. Excellent suspended solids and organics removal efficiencies can be generally achieved in these systems (>80% for TSS and >90% for BOD) with plants having a relatively small impact. Columns had an acceptable infiltration capacity after one year of operation. When planted with effective species (e.g. Carex appressa and Canna lilies ), it is expected that performance will not be significantly affected by longer rest periods and higher pollutant concentrations in the early years of system operation. The results of this study, thus, demonstrate that innovative and aesthetically pleasing living walls can be designed for treatment of greywater at the household scale. [ABSTRACT FROM AUTHOR]

Chemically enhanced primary treatment (CEPT) can be used to mitigate the adverse effect of wet weather flow on wastewater treatment processes. In particular, it can reduce the particulate pollution load to subsequent secondary unit processes, such as biofiltration, which may suffer from clogging by an overload of particulate matter. In this paper, a simple primary clarifier model able to take into account the effect of the addition of chemicals on particle settling is presented. Control strategies that optimize the treatment process by chemical addition were designed and tested by running simulations with this CEPT model. The most adequate control strategy in terms of treatment performance, chemicals saving, and maintenance effort was selected. Full-scale implementation of the controller was performed during the autumn of 2015, and the results obtained confirmed the behaviour of the controlled system. Practical issues related to the implementation are presented. [ABSTRACT FROM AUTHOR]

The discharge of poorly decontaminated winery wastewater remains a serious environmental problem in many regions, and the industry is welcoming improved treatment methods. Here, an innovative decontamination approach integrating Fenton's process with biofiltration by Asian clams is proposed. The potential of this approach was assessed at the pilot scale using real effluent and by taking an actual industrial treatment system as a benchmark. Fenton peroxidation was observed to remove 84% of the effluent's chemical oxygen demand (COD), reducing it to 205 mg L-1. Subsequent biofiltration decreased the effluent's COD to approximately zero, well below the legal discharge limit of 150 mg L-1, in just 3 d. The reduction of the effluent's organic load through Fenton's process did not decrease its toxicity toward Vibrio fischeri, but the effluent was much less harmful after biofiltration. The performance of the treatment proposed exceeded that of the integrated Fenton's process-sequencing batch reactor design implemented in the winery practice, where a residence time of around 10 d in the biological step typically results in 80 to 90% of COD removal. The method proposed is effective and compatible with typical winery budgets and potentially contributes to the management of a nuisance species. [ABSTRACT FROM AUTHOR]

Nitrogen oxides (NO x), including nitrogen monoxide (NO) and nitrogen dioxide (NO 2), are among the most important global atmospheric pollutants because they have a negative impact on human respiratory health, animals, and the environment through the greenhouse effect and ozone layer destruction. NO x compounds are predominantly generated by anthropogenic activities, which involve combustion processes such as energy production, transportation, and industrial activities. The most widely used alternatives for NO x abatement on an industrial scale are selective catalytic and non-catalytic reductions; however, these alternatives have high costs when treating large air flows with low pollutant concentrations, and most of these methods generate residues that require further treatment. Therefore, biotechnologies that are normally used for wastewater treatment (based on nitrification, denitrification, anammox, microalgae, and combinations of these) are being investigated for flue gas treatment. Most of such investigations have focused on chemical absorption and biological reduction (CABR) systems using different equipment configurations, such as biofilters, rotating reactors, or membrane reactors. This review summarizes the current state of these biotechnologies available for NO x treatment, discusses and compares the use of different microorganisms, and analyzes the experimental performance of bioreactors used for NO x emission control, both at the laboratory scale and in industrial settings, to provide an overview of proven technical solutions and biotechnologies for NO x treatment. Additionally, a comparative assessment of the advantages and disadvantages is performed, and special challenges for biological technologies for NO abatement are presented. [Display omitted] • The slightly solubility of NO is a limitation for the implementation of biological treatments. • A mass transfer vector is necessary to improve NO solubility so that biological systems can be implemented at an industrial level. • CABR systems with F e (I I) E D T A 2 − are the most widely used biological treatments for the biological treatment of NO. • The maximum removal capacity reported is 103.22 g NO·m-3· h-1 with F e (I I) E D T A 2 − in a biotrickling filter. [ABSTRACT FROM AUTHOR]

Wastewater stabilization ponds (WSPs) are common for wastewater treatment in remote Canadian Arctic communities. In this paper, two geotextiles of different mass/unit areas are examined as a potential biofiltration upgrade to existing WSPs in arctic summer conditions. The intended role of the geotextile is to provide additional treatment of municipal wastewater seeping from these WSPs. Column filtration experiments were performed using municipal wastewater in a controlled laboratory environment at either 10 °C or 2 °C. The columns contained one of two different nonwoven geotextiles over 10 cm of gravel, simulating a WSP berm in contact with exfiltrating wastewater. Weekly wastewater samples were taken upstream and downstream of the geotextile/gravel filter and were analyzed for a suite of water quality parameters; the hydraulic conductivity of the columns was also measured weekly. Results showed that it is possible to accumulate biomass on geotextile material over a 3 month period at these temperatures, which corresponded with 1–2 log reductions in hydraulic conductivity. Significant removal of total suspended solids, 5-day biochemical oxygen demand, total nitrogen, and total phosphorus was observed; however, removal efficiencies for most parameters were reduced at the lower temperature. This study demonstrates that geotextiles could be used to enhance the performance of WSP systems operating in arctic climates. [ABSTRACT FROM AUTHOR]

Aims A batch chlorination system was optimized for on-site wastewater treatment and reuse system ( OWRS) and its efficiency was evaluated for reducing viruses, protozoa, bacteria and antimicrobial resistance in cold and warm seasons. Methods and Results The OWRS performance in reducing microbial contaminants was determined by assessing three different faecal indicators ( Escherichia coli, F-specific coliphages and Clostridium perfringens for measuring the disinfection efficiency of bacteria, viruses and spore-formers and surrogate for protozoa, respectively) using culture-based methods. Quantitative PCR was used to quantify pathogenic bacteria (Shiga-toxin-producing E. coli ( STEC), Campylobacter spp., and Arcobacter spp.), a human-associated faecal marker ( gyrB), and tetracycline resistant bacteria ( tetQ). The levels of E. coli, coliphages and Cl. perfringens showed 5·4, 2·3, 2·5 log reduction, respectively, upon disinfection. In the final effluents, coliphages (1·7 × 102 PFU 100 ml−1) and Cl. perfringens (3·4 CFU 100 ml−1) were detected in 80 and 100% of the samples, but E. coli was not found. The removal and inactivation of E. coli and Cl. perfringens were not significantly different across the seasons, however, efficacy of removal and inactivation of F-specific coliphage was significantly reduced during the winter/spring season compared to the summer/autumn season ( P = 0·009). The reduction of Arcobacter, gyrB and tetQ by 3·1, 2·3 and 2·3 log, respectively, was mostly due to peat biofiltration under the study conditions. Conclusions This study demonstrated that peat biofiltration was the most important step of the OWRS to remove microbes and genes from wastewater before spray irrigation of the effluents. The irrigation system is not suitable for edible crops because of the potential presence of residual pathogens. Significance and Impact of the Study On-site wastewater treatment systems are a practical option for reusing the wastewater for landscape, especially for those areas where geological and seasonal limitations impact the removal of microbial contaminants by soil infiltration. [ABSTRACT FROM AUTHOR]

Biofiltration is a sustainable technology in the US that utilizes microorganisms to biodegrade harmful airborne contaminants. Biofiltration can not only be more cost effective, but also more environmentally friendly than traditional technologies such as thermal oxidation and chemical scrubbing. The objective of this study was to follow the long-term operation of a lava rock-based biofilter for odour control at a wastewater treatment plant. The biofilter has operated well for over 14 years that we have followed the system. After 14 years of operation there are no visible signs of fungal growth or solid support breakdown. VOCs were removed at a rate of nearly 81% while ammonia and hydrogen sulfide removal was found to be almost 90% and 98%, respectively. This study demonstrates that lava rock can be used for a solid support media in wastewater treatment applications with excellent removal efficiencies, while maintaining its structural integrity over a decade or more of continuous use. This is the first study that has followed a biofilter operation for 14 years. When considering biofiltration as an odour treatment option, one should consider lava rock as a solid support option. The initial capital investment can be saved several times over by using a solid support that is able to hold-up over the years without replacement. Thus, it is practical to consider solid support materials that appear to have a larger capital cost when one considers a long media life expectancy and payback over decades. [ABSTRACT FROM AUTHOR]

Advanced oxidation of active pharmaceutical ingredients (APIs) in wastewater produces transformation products (TPs) that are often more biodegradable than the parent compounds. Secondary effluent from a wastewater treatment plant was treated using UV-based advanced oxidation (LPUV/H2O2 and MPUV/NO3) followed by biological aerated filtration (BAF), and different APIs and their transformation products were monitored. The advanced oxidation processes degraded the APIs by 55-87% (LPUV/H2O2) and 58-95% (MPUV/NO3), while minor loss of APIs was achieved in the downstream BAF system. Eleven TPs were detected following oxidation of carbamazepine (5) and iopromide (6); three key TPs were biodegraded in the BAF system. The other TPs remained relatively constant in the BAF. The decrease in UV absorbance (UVA254) of the effluent in the BAF system was linearly correlated to the degradation of the APIs (for the MPUV/NO3BAF), and can be applied to monitor the biotransformation of APIs in biological-based systems. [ABSTRACT FROM AUTHOR]

A full-scale nitrifying biofilter was continuously monitored during two measurement periods (September 2014; February 2015) during which both gaseous and liquid N 2 O fluxes were monitored on-line. The results showed diurnal and seasonal variations of N 2 O emissions. A statistical model was run to determine the main operational parameters governing N 2 O emissions. Modification of the distribution between the gas phase and the liquid phase was observed related to the effects of temperature and aeration flow on the volumetric mass transfer coefficient (k L a). With similar nitrification performance values, the N 2 O emission factor was twice as high during the winter campaign. The increase in N 2 O emissions in winter was correlated to higher effluent nitrite concentrations and suspected increased biofilm thickness. [ABSTRACT FROM AUTHOR]

Odorous emissions from wastewater treatment plants (WWTPs) are an annoyance for neighboring communities. This article, for the first time, quantitatively reports on an evaluation of the presence of fecal odorants identified in air samples from two exemplary WWTPs by the odor profile method (OPM) and chemical analysis. The fecal odorants indole and skatole were identified by Gas Chromatography-Mass Spectrometry. The odor threshold concentration of skatole was determined to be 0.327 ng/L (60 pptV) in Teflon Bags by an expert panel. Skatole was found to be the primary chemical leading to fecal odor, due to its odor concentration to odor threshold concentration ratio that ranged from 2.8 to 22.5. The Weber-Fechner law was followed by pure skatole, but was not applicable when there was a mixture of fecal odorants and other odorant types present in WWTP air emission samples. This is probably caused by antagonism with other odorant types. Several existing odor control treatment methods for fecal odorants were evaluated at different wastewater treatment operations at two WWTPs by the OPM and chemical analysis for indole and skatole. Chemical scrubbing and biofiltration performed best in removing fecal odors among current control technologies. [ABSTRACT FROM AUTHOR]

In this study, nitrous oxide (N 2 O) emissions from a full-scale denitrifying biofilter plant were continuously monitored over two periods (summer campaign in September 2014 and winter campaign in February 2015). Results of the summer campaign showed that the major part (> 99%) of N 2 O flux was found in the liquid phase and was discharged with the effluent. N 2 O emissions were highly variable and represented in average 1.28 ± 1.99% and 0.22 ± 0.31% of the nitrate uptake rate during summer and winter campaigns, respectively. Denitrification was able to consume a large amount of dissolved N 2 O coming from the upstream nitrification stage. In the absence of methanol injection failure and with an influent BOD/NO 3 -N ratio higher than 3, average reduction of N 2 O was estimated to be of 93%. The control of exogenous carbon dosage is essential to minimize N 2 O production from denitrifying biofilters, in correlation to NO 2 -N concentrations in the filter. [ABSTRACT FROM AUTHOR]

The combination of biological and chemical oxidation processes is an interesting approach to remove ready, poor, and non-biodegradable compounds from complex industrial wastewaters. In this study, biofiltration followed by HO/UV oxidation (or microfiltration) and final reverse osmosis (RO) step was employed for tertiary treatment of an oil refinery wastewater. Biofiltration alone allowed obtaining total organic carbon (TOC), chemical oxygen demand (COD), UV absorbance at 254 nm (UV254), ammonium, and turbidity removal of around 46, 46, 23, 50, and 61 %, respectively. After the combined biological-chemical oxidation treatment, TOC and UV254 removal amounted to 88 and 79 %, respectively. Whereas, the treatment performance achieved with different UV lamp powers (55 and 95 W) and therefore distinct irradiance levels (26.8 and 46.3 mW/cm, respectively) were very similar and TOC and UV254 removal rates were highly affected by the applied C/HO ratio. Silt density index (SDI) was effectively reduced by HO/UV oxidation, favoring further RO application. C/HO ratio of 1:4, 55 W UV lamp, and 20-min oxidation reaction corresponded to the experimental condition which provided the best cost/benefit ratio for TOC, UV254, and SDI reduction from the biofilter effluent. The array of treatment processes proposed in this study has shown to be adequate for tertiary treatment of the oil refinery wastewater, ensuring the mitigation of membrane fouling problems and producing a final effluent which is suitable for reuse applications. [ABSTRACT FROM AUTHOR]

The simultaneous treatment of N 2 O-laden air emissions and domestic wastewater was assessed in a novel denitrifying bioscrubber composed of a packed bed absorption column interconnected to a fixed bed reactor (FBR). The influence of liquid recycling velocities ( U L ) and gas empty bed residence times (EBRTs) in the absorption column on bioscrubber’s performance was evaluated using synthetic wastewater (SW) and a 100 ± 8 ppm v N 2 O air emission. Steady state N 2 O removal efficiencies of 36 ± 3% concomitant with SW total organic carbon removals of 91 ± 1% were achieved at an EBRT of 3 min and at the highest U L tested (8 m h −1 ). The removal of dissolved N 2 O by heterotrophic denitrification in the FBR constituted the main N 2 O biodegradation mechanism and limited the abatement of N 2 O. While the supplementation of SW with Cu 2+ (a cofactor of the N 2 O reductase) did not result in an enhancement in N 2 O reduction, the increase in FBR volume supported a higher N 2 O removal. The increase in EBRT up to 40 min supported an enhancement in the gas N 2 O removal of up to 92%. The DGGE-sequencing analysis of FBR microbial population revealed a high microbial diversity and the abundance of denitrifying bacteria capable of reducing N 2 O to N 2 . [ABSTRACT FROM AUTHOR]

The biofiltration system over organic bed (BFOB) uses organic filter material (OFM) to treat municipal wastewater (MWW). This study evaluated the performance of a BFOB system employing mesquite wood chips (Prosopis) as OFM. It also evaluated the effect of hydraulic loading rates (HLRs) in order to achieve the operational parameters required to remove organic matter, suspended material, and pathogens, thus meeting Mexican and US regulations for reuse in irrigation. Two biofilters (BFs) connected in series were installed; the first one aerated (0.62 m³air m-2h-1) and the second one unaerated. The source of MWW was a treatment plant located in Durango, Mexico. For 200 days, three HLRs (0.54, 1.07, and 1.34 m³m-2d-1) were tested. The maximum HLR at which the system showed a high removal efficiency of pollutants and met regulatory standards for reuse in irrigation was 1.07 m³m-2d-1, achieving removal efficiencies of biochemical oxygen demand (BOD5) 92%, chemical oxygen demand (COD) 78%, total suspended solids (TSS) 95%, and four log units of fecal coliforms. Electrical conductivity in the effluent ensures that it would not cause soil salinity. Therefore, mesquite wood chips can be considered an innovative material suitable as OFM for BFs treating wastewaters. [ABSTRACT FROM AUTHOR]

The presence of endocrine disrupting compounds (EDCs), pharmaceutically active compounds (PhACs) and artificial sweeteners are of concern to water providers because they may be incompletely removed by wastewater treatment processes and they pose an unknown risk to consumers due to long-term consumption of low concentrations of these compounds. This study utilized pilot-scale conventional and biological drinking water treatment processes to assess the removal of nine PhACs and EDCs, and two artificial sweeteners. Conventional treatment (coagulation, flocculation, settling, non-biological dual-media filtration) was compared to biofilters with or without the addition of in-line coagulant (0.2–0.8 mg Al 3 + /L; alum or PACl). A combination of biofiltration, with or without in-line alum, and conventional filtration was able to reduce 7 of the 9 PhACs and EDCs by more than 50% from river water while artificial sweeteners were inconsistently removed by conventional treatment or biofiltration. Increasing doses of PACl from 0 to 0.8 mg/L resulted in average removals of PhACs, EDCs increasing from 39 to 70% and artificial sweeteners removal increasing from ~ 15% to ~ 35% in lake water. These results suggest that a combination of biological, chemical and physical treatment can be applied to effectively reduce the concentration of EDCs, PhACs, and artificial sweeteners. [ABSTRACT FROM AUTHOR]

Cocopeat, a by-product of coconut processing plants widely available in Vietnam, Thailand, Cambodia, the Philippines, and Indonesia, was studied for its ability to support biological nutrient removal in lab-scale vertical flow columns treating simulated wastewater. Treatment performance for cocopeat was compared to sphagnum peat, a traditional packing medium, and Celite, an inert clay pellet. Removal efficiencies of nitrogen, phosphorus, and biological oxygen demand (BOD) were measured over a period of 325 days. During the treatment period, varying configurations were tested to determine the effect of varying aerobic, anoxic, and anaerobic zones on nutrient removal. Overall, similar BOD removal profiles were obtained for cocopeat and sphagnum peat. Slightly more efficient anoxic conditions and a less acidic environment developed with the cocopeat. Up to 75% nitrogen removal was obtained; however, phosphorus removal was not accomplished using the experimental setup, likely due to the absence of a completely anaerobic treatment zone. Overall, cocopeat appears to be a promising alternative packing material for on-site wastewater treatment in Southeast Asia in terms of nitrogen removal. [ABSTRACT FROM AUTHOR]

Cocopeat, a byproduct of coconut processing, was evaluated as a packing medium in vertical flow constructed wetlands for the treatment of septic tank effluent in the Mekong Delta of Vietnam. Vertical flow constructed wetlands are typically packed with gravel and then planted with ornamental plants. For this study, varying percentages of cocopeat were added to the gravel and the systems assessed for supplemental treatment efficiency. A secondary treatment step of gravel planters with ornamental plants was assessed for supplemental treatment efficiency. Removal efficiencies of nitrogen, phosphorus, coliform, and biological oxygen demand were measured. Microbial community samples were collected periodically in order to chronologically analyze community shifts within and between different wetland cells. Ammonium transformation and removal was greater than 95% in each wetland containing cocopeat throughout the course of the study. Ammonium concentrations were significantly higher in the effluent of the wetland without cocopeat, indicating reduced nitrification activity, suggesting that cocopeat was critical for supporting nitrification. At steady state, each wetland had significantly lower phosphate concentrations than the influent. Complete removal of ammonium or phosphate in the constructed wetlands was not achieved; however, a secondary treatment step consisting of ornamental planters provided additional removal. This field study suggests that cocopeat is an adequate packing medium for constructed wetlands treating wastewater in Southeast Asia. [ABSTRACT FROM AUTHOR]

The effluent of a wastewater treatment plant was treated in a pilot plant for reclaimed water production through the denitrification biofilter (DNBF) process, ozonation (O), and biologic aerated filtration (BAF). The combined process demonstrated good removal performance of conventional pollutants, including concentrations of chemical oxygen demand (27.8 mg·L) and total nitrogen (9.9 mg·L) in the final effluent, which met the local discharge standards and water reuse purposes. Micropollutants (e.g., antibiotics and endocrine-disrupting chemicals) were also significantly removed during the proposed process. Ozonation exhibited high antibiotic removal efficiencies, especially for tetracycline (94%). However, micropollutant removal efficiency was negatively affected by the nitrite produced by DNBF. Acute toxicity variations of the combined process were estimated by utilizing luminescent bacteria. Inhibition rate increased from 9% to 15% during ozonation. Carbonyl compound concentrations (e.g., aldehydes and ketones) also increased by 58% as by-products, which consequently increased toxicity. However, toxicity eventually became as low as that of the influent because the by-products were effectively removed by BAF. The combined DNBF/O/BAF process is suitable for the advanced treatment of reclaimed water because it can thoroughly remove pollutants and toxicity. [ABSTRACT FROM AUTHOR]