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The present study demonstrates the vermistabilization of paper mill wastewater sludge (PMS) spiked with cow dung (CD) employing indigenous epigeic earthworm Perionyx excavatus Perrier. A total of six treatments were prepared along with a positive control (PC) and negative control (NC). Twenty earthworms were released into each treatment including PC and NC without earthworms. The different proportions viz., T1 (CD – 100%), T2 (PMS:CD – 1:3), T3 (PMS:CD – 1:2), T4 (PMS:CD – 1:1), T5 (PMS:CD – 3:1), T6 (PMS:CD – 2:1), PC (PMS – 100%) and NC (PMS – 100%) and changes in chemical parameters and microbial properties were recorded during the course of 60 days. Vermistabilization caused a significant decrease in the level of heavy metals: Cd (2.9–27.8%), Cu (0.22–42.3%), Pb (1.3–56.3%) and Cr (0.8–46.2%). The bioconcentration factor (BCFs) was also calculated and great amount of heavy metals accumulated in their body (mg kg−1) that ranged from 0.31 ± 0.003–0.45 ± 0.007 for Cd, 0.12 ± 0.005–0.24 ± 0.003 for Cu, 0.15 ± 0.005–0.31 ± 0.006 for Pb and 0.29 ± 0.007–0.56 ± 0.001 mg kg−1 for Cr, accumulation of heavy metals are in the order: Cr > Cd > Pb > Cu. The physicochemical parameters of earthworm treated substrate such as electrical conductivity, total nitrogen, total phosphorus and total potassium were significantly increased; whereas, pH, total organic carbon, C:N ratio (carbon: nitrogen) and C:P ratio (carbon: phosphorus) were reduced after 60 days of vermistabilization. The vermistabilized materials also had a higher population of bacteria (98.90 ± 0.30 CFU × 106 g−1), fungi (43.75 ± 0.55 CFU × 103 g−1) and actinomycetes (67.65 ± 0.45 CFU × 105 g−1) than initial mixtures. Moreover, several histopathological changes were observed in earthworm tissues viz., disintegration of cells, irregular surface of epidermis, cellular debris, irregular cellular compartmentation, and oval-shaped nucleus. Higher level of histopathological abnormalities was recorded in PC (PMS-100%) while none were detected in lower concentrations of PMS. Furthermore, the study concludes that the paper mill sludge in a mixture of cow dung (1:1 ratio) can be a useful proposition for utilizing this hazardous waste through the adoption of vermitechnology.

The results of physico-chemical analysis of pulp and paper mill effluent sedimented sludge revealed the presence of heavy metals (mg l−1) Fe (67.53), Zn (13.90), Cu (2.15), Cr (2.30), Cd (0.255), Mn (11.0), Ni (3.30), and Pb (1.05) along with persistent chlorolignin. The major persistent organic pollutants detected by GC–MS were ethane, 1,1-diethoxy; tetradecanoic acid; furane 2,5-dimethyl; n-hexadecanoic acid; nonacosane, trimethylenebis-1,3-dioxolane; 1,3-dioxolane, 2-(phynylmethyl). Twelve representative native plants were noted based on their population number growing on pulp and paper sludge and evaluated for their phytoextraction potential of heavy metals. The result revealed that Triticum aestivum was found as root accumulator for all metals except Cu. Similarly, the Brassica campestris accumulated all metals maximum in root except Ni, Fe and Pb. While, Eclipta alba accumulated majority of metals in their shoot and leaves, But Solanum nigrum, Rumex dentatus accumulated metals in root and shoot both. Rananculus scleratus accumulated all the tested metals in their aerial parts except Cd and Pb. Cammelina benghalensis accumulated metals in root except Cd, Pd. Similarly the Phragmites cummunis and Ricinus cummunis accumulated majority of metals in their shoot and leaves. It was also noted that several evaluated plant showed bioconcentration factor (BCF) greater than one for accumulated metals i.e. Pb in T. aestivum (1.285), C. benghalensis (5.142), Cannabis sativa (3.466), P. cummunis (7.180), R. cummunis (66.80) was also noted. Furthermore, greater than one translocation factor (TF) for all these plants showed strong evidence for phytoextraction and in situ remediation potential of these plants. The overall order of phytoextraction potential of native wetland plants were C. sativa > P. cummunis > C. benghalensis > T. aestivum > B. campestris > E. alba.

Heavy metal content has become a serious issue with increase in compost application in agricultural land. The bioavailable fraction (water soluble and diethylene triamine pentaacetic acid (DTPA) extractable) is the major concern comparing to the total concentration as it can be taken up by plants which in turn affects the human health. Thus, this study was carried out to determine the variation in bioavailable and leachable fraction of heavy metals (Cd, Cu, Fe, Ni, Pb, Cr, Zn, Hg and Mn) and to assess the influence of temperature, pH, organic matter degradation and humification during rotary drum composting of paper mill sludge (PMS) for 20 days. A total concentration of all the metals as well as nutrients increased during composting. The Hg was not detected in water soluble and DTPA extractable fraction, whereas Pb and Cr were also not detected in water soluble fraction in all the trials. A decreasing trend was observed in leachable quantity for all the metals during composting. Water extractable quantity increased for Fe and Cu during composting. Organic matter degradation and humification during composting influences the variation in bioavailability and leachability of heavy metals, which can be optimized by applying appropriate proportion of cow dung during rotary drum composting of PMS.

The present study deals with the bioremediation of potentially hazardous pulp and paper mill effluent by a laccase producing Paenibacillus sp. strain LD-1 (JX499920) isolated from contaminated soil sample by lignin enrichment method. The bacterium effectively reduced pollution parameters (colour 68%, lignin 54%, phenol 86%, BOD 83% and COD 78%) after 144 h of treatment at 34 ± 1 °C and 120 rpm. GC–MS analysis of control and treated samples showed that concentration of most of the low molecular weight phenolic compounds like 2-methoxyphenol, 2,6-dimethoxy phenol, 2-methoxy-4-ethyl-phenol, 3-allyl-6-methoxyphenol, ethanone 1-(-4-hydroxy-3,5-dimethoxyphenyl), benzoic acid, 2-methoxy-4-(1-propenyl) phenol and 4-methoxycinnamic acid present in control untreated effluent were reduced after bacterial treatment. The toxicity assessments were carried out with treated and untreated effluent by studying the growth and germination of seeds of mung bean (Vigna radiata L.). The mung bean bioassay confirmed the detoxification of effluent after bacterial treatment.

This study investigates the predictive ability of gene-expression programming (GEP) in the estimation of methane yield (Ym) and effluent substrate (Se) produced by two anaerobic filters. The modeling study was carried out using the data obtained from two upflow anaerobic filters – one mesophilic (35 °C) and one thermophilic (55 °C) – operated for the treatment of paper-mill wastewater under varying organic loadings. The GEP model was composed of three inputs, hydraulic retention time (Thr), organic loading rate (Rol), and influent substrate (Si), and one output, either Se or Ym. The Stover–Kincannon model was also used for data analysis and to evaluate the prediction ability. Three statistical criteria, root mean square error (RMSE), determination coefficient (R2), and Akaike's information criteria (AIC), were the means used for comparison. The results showed that the GEP approach predicted the performance of both anaerobic filters much better than the Stover–Kincannon model.

The largest Phragmites reed field in the world, with a historical area of approximately 1000 km 2 , is located in the Liaohe Delta in northeastern China. The Phragmites wetlands are extensively managed to maximize the production of reed biomass for the paper industry. Based on satellite remote sensing we estimated that the total area of the Phragmites wetlands has decreased from 857 km 2 in 2003 to 786 km 2 in 2009 to accommodate oil field infrastructure and societal developments. However, at the same time the production of Phragmites biomass used for the production of reed pulp has increased to 400,000 metric tons per year. This paper describes the great efforts that have been made to increase the Phragmites yields for the paper industry, including (1) diversion of freshwater from rivers to the Phragmites fields, (2) management of the water table, (3) harvesting and burning for pest control, and (4) seawater irrigation to rehabilitate Phragmites fields infested with weeds. The paper industry has facilitated the conservation of the Phragmites wetlands and their associated ecosystem services. Besides being a source for fiber, the wetlands provide important habitat for wildlife, sequester carbon, and create job opportunities and economic income for the local people.

The efficiency of active aeration (AE) of constructed wetlands expressed as the ratio between implied oxygen consumption and oxygen delivered to the system is comprehensively reviewed in this paper. The aeration efficiency appears to be rather low with a mean value of 1.73% and median value of 0.48% of oxygen used in the systems for situations with only partial aerobic degradation of the pollutants. For full aerobic degradation, the mean value of AE is 3.74% but median value is much lower 1.08%. For both cases, the standard deviation is higher than the mean value (4.95% and 10.87% respectively), so there is a lot of variability in the data. For systems with the Forced Bed Aeration the results are more uniform and are close to the literature values given for this system, which is an implication that the proposed methodology might be potentially used for rough estimate of the aeration efficiency.

Management of industrial sludge is a big challenge for developing countries. Composting is an economical and viable option to manage and treat an industrial sludge. However, efficient compost production requires nature of materials involved, process understanding and physics behind the process. We investigated the physical parameters during composting of solid pulp and paper mill sludge in 550 L rotary drum composter. Variation in physical parameters such as bulk density, volatile solids, moisture content, free air space, void ratio, ash content and particle density were analyzed over the period of composting. Bulk density was observed increasing, whereas free air space was showed declining trend and observed 52% in end compost. The particle density was observed to be increasing from 610 to 680 kg m−3. End compost was analyzed for nutritional parameters and seen to be increasing over the period of composting. A strong relationship was found between various physical parameters. Pearson’s correlation coefficient matrix was formed between free air space, bulk density, moisture content and particle density.

In this paper, we analysed the pollutant removal efficiency and reliability of a vertical and horizontal flow hybrid constructed wetland (CW) planted with giant miscanthus and Jerusalem artichoke. The wastewater treatment plant, located in south-eastern Poland, treated domestic sewage at an average flow rate of 1.2 m3·d−1. The tests were carried out during. 5-years of operation of the sewage treatment plant (2011–2016). During this period, sewage samples were collected from three stages of wastewater treatment in four seasons (winter – February, spring – May, summer – August, and autumn – November). The following parameters were measured: BOD5, COD, total suspended solids, total nitrogen, and total phosphorus. The average effectiveness of organic pollutant removal expressed by BOD5 and COD was 98.8 and 97.6%, respectively, and the removal efficiency for total suspended solids was 93%. The average values of BOD5, COD, and total suspended solids in wastewater discharged to the receiver were significantly lower than the limit values required in Poland. The efficiency of total nitrogen and total phosphorus removal was 64.1 and 68.1%, respectively, and the average values of these components in the outflow from the treatment plant exceeded the standard levels. A reliability analysis performed using the Weibull probability model showed that the reliability of pollutant removal in the tested CW system was very high for BOD5 and COD (100%). It was also demonstrated that the tested CW did not provide effective elimination of biogenic elements (nitrogen and phosphorus), as evidenced by the low reliability values – 32 and 28%, respectively. The investigated hybrid CW system with giant miscanthus and Jerusalem artichoke removed organic and biogenic pollutants with a similar efficiency as systems using classic plant species such as reed and willow.

To date, the process of biodrying has been used for the drying of biodegradable waste materials to produce fuel. However, different applications other than incineration also exist for dried materials: e.g., sewage sludge could be used as a fertilizer. This paper investigates the potential of biodrying as a pretreatment method prior to the application of sewage sludge in agriculture. Experiments were performed in two biodrying reactors with operational volumes of 100 dm3 using two different aeration regimes to compare the efficiency of the two process alternatives: i) mesophilic conditions and ii) a full composting temperature profile including the thermophilic phase. The influence of the two different operating regimes on the elimination of pathogens and selected pharmaceuticals and personal care products (PPCPs) was investigated. Phospholipid fatty acid (PLFA) analysis was employed to identify the main groups of microorganisms responsible for the potential elimination of the detected micropollutants. The results showed that antibiotic activity was completely eliminated under both the operational regimes. Bisphenol-A (BPA) and irgasan (IRG) were detected in the untreated sludge, and the elimination efficiency for these substances was greater in the reactor with the mesophilic treatment (max. 88.3% for BPA and 47.7% for IRG) than under thermophilic conditions (60.1% for BPA and no significant removal of IRG). PLFA analysis indicates that Actinobacteria could be responsible for the biodegradation. Of the two indicator microorganisms used for the verification of the efficiency of the improvement in hygiene, only E. coli were completely eliminated under both regimes, while the enterococci content was reduced by 4 orders of magnitude. The results of this study document that the biodrying process possesses the potential for the removal of micropollutants from sewage sludge and might serve as a pretreatment process prior to using the treated sludge in agriculture.

The application of agricultural by-products as filter bed material for the treatment of oily wastewater is preferable due to their biodegradability and availability. The goal of this paper was to examine the sorption and filtration properties of sunflower (Lat. Helianthus annuus ) fibres in a raw state. SEM imaging and nitrogen adsorption at −196.15 °C were applied to evaluate sorbent morphology. FTIR spectroscopy was used to determine the chemical composition of the pith. Studies on sorption in static conditions (pith fragmentation 1.5–4.0 mm) allowed process kinetics to be specified. The experimental kinetics was fitted to pseudo first-order and pseudo second-order kinetics by a non-linear method. To better predict kinetic parameters, a new modified logistic equation was proposed. Sunflower fibre was found to have high oil sorption capacity (12.67 g/g) and good retention properties. During filtration experiments, an artificial reservoir brine (0.1, 2.0, and 20.0 g/l of oil) was used as an oil-in-water emulsion; sunflower pith was used as a filter medium. The influence of four process parameters (pH, bed height, initial oil concentration, and flow rate) on removal efficiency was studied. Oil concentrations were determined by gas chromatography. The results demonstrated that the prepared filters operated better at a lower pH, lower flow, a deeper bed material, and higher concentration of inlet oil. The filtration efficiency for the removal of crude oil from oily brines reached more than 99% in the initial stage of the process. The results obtained suggest that natural plant fibres can be an effective bed material to separate oil from oily brine.

Denitrifying bioreactors are simple, low-cost ecotechnologies designed to reduce nitrate (NO3−) present in septic tank effluent and drainage water. Recent studies indicate that, in addition to significant reduction in NO3− loads, these systems are also able to remove microbial contaminants from municipal wastewater. However, the removal of microbial contaminants in denitrifying bioreactors remains poorly characterised and factors that control removal in denitrifying bioreactors remain unexplored. In this study, the removal efficiency of faecal indicator bacteria Escherichia coli (E. coli) and total coliforms (TC) as a model for bacterial pathogens and F-specific RNA bacteriophage (FRNA bacteriophage) as a model for viruses was assessed for mesocosm-scale (∼700 L) bioreactors receiving municipal wastewater. Systems were filled with two different slow-release carbon sources: woodchip and coconut husk. The effect of media age on attenuation of microbial contaminants was assessed by comparing the performance of 8-year old systems with equivalent newly constructed woodchip and coconut husk bioreactors. Additionally, removal performance of these carbon substrates was compared to that of gravel, a non-carbon substrate commonly used in subsurface flow (SSF) constructed wetlands. Substantial reduction of E. coli, TC and FRNA bacteriophage from primary treated municipal wastewater was achieved in all bioreactors. Mean annual log10 removal efficiencies were similar between microbial indicators ranging from 1.4 to 1.9 for TC, 1.3 to 1.8 for E. coli and 1.3 to 2.0 for FRNA bacteriophage. All denitrifying bioreactors showed consistent year-round performance and long-term performance which did not markedly change in the ninth year of operation. The woodchip or coconut husk bioreactors achieved microbial effluent quality within the same range of log10 removal rates achieved in gravel-based systems. This suggests that denitrifying bioreactors, as well as reducing N loads, can effectively reduce microbial contaminants in wastewater, providing a complimentary disinfection role. Further research is needed to increase understanding of factors affecting removal of microbial contaminants in denitrifying bioreactors to support design of these systems for microbial contaminant removal.

The current study was carried out to test the removal of nitrogen and phosphorus from olive mill wastewater (OMW) by combination of sand filter and a mixture of aquatic plants ( Phragmites australis , Typha latifolia and Arundo donax ). The experimental pilot was composed of two serial systems: sand filter followed by vertical flow constructed wetlands (VF-CWs). The sand filter was filled with 50 cm of sand and 10 cm of gravel in the top and the bottom of the filter. The second step of the treatment consists of a tank (1 × 1 × 1 m 3 ) filled with 20 cm of gravel and 60 cm of soil, planted with a mixture of aquatic plants at a density of 8 young plants/m 2 for each plant and irrigated twice in the week by 20L of preliminary filtered OMW. During all experiment, OMW was diluted with domestic wastewater at a ration 1/1 (v/v). Mean diluted OMW concentrations were 2.05 g/L, 1.52 g/L, 1.94 mg/L, 1.70 mg/L, 0.22 g/L, 0.30 g/L, 26.78 g/L and 20.47 g/L for TKN-N, NH 4 + -N, NO 2 − -N, NO 3 − N, ortho-phosphate (OP), Total phosphorus (PT) total COD and dissolved COD respectively. Despite the rather high influent concentrations, the performance of the sand filter was very effective since it achieved average removals of about 60.4%, 74.4%, 80.61%, 97.85%, 96.45%, 79.75% and 76.75% for NTK, NH 4 + , NO 3 − , PO 4 3− , PT total COD and dissolved COD respectively. The presence of aquatic plants was more efficient in removing of nutrients and organic load. The average elimination of experimental system (sand filter + VF-CWs) in terms of flow was 62.48% for NTK, 90.43% for NH 4 + , 77.25% for NO 3 − , 98.51% for PO 4 3− , 97.53% for PT and 99.05% for total COD. In general, this study shows potential application of the experimental system to achieve nutrient and COD removal from OMW. Although the percent removal of organic matter and nutrients from OMW was very high, final OMW concentrations remained high, thus preventing their use for irrigation or immediate disposal into the environment.

The paper discusses the effectiveness of removing ammonium ions and indicator bacteria from domestic sewage in a vertical flow filter filled with a plastic material (PET flakes). Preliminary research has shown the effectiveness of ammonium nitrogen removal at the value of 66.74%. Principal Component Analysis was used to determine the mechanism of the removal of indicator bacteria. Three principal components were identified and they were responsible for 78,2% of input data variability. PCA analysis showed, that the effectiveness of Escherichia coli removal depended mainly on the filtering mechanism. In the case of coliform bacteria removal an additional factor was acidic conditions. A decrease in CFU of the coliform bacteria by one order of magnitude was observed at pH = 4.1.

The experiment was conducted to evaluate the role of vermicompost as strong buffer and natural adsorbent to reduce the transition metals, BOD, COD, total dissolved solids (TDS) and total suspended solid (TSS) under laboratory condition from three industrial effluent viz. beverage, distillery and paper mill. Adsorbent (vermicompost) prepared from cow dung with the help of exotic earthworm Eisenia fetida was used in a glass column reactor (38 cm × 3.2 cm i.d). The effluents were passed through the different amount of vermicompost (20 g, 50 g and 100 g) with particle size upto 230 μm. The maximum adsorption capacity was studied by applying the linear Langmuir and Freundlich isotherm model. The maximum adsorption was noticed for Cu and the least for Zn. Freundlich adsorption isotherm was best fitted for Cu in distillery effluent ( n = 4.25) followed by Mn in beverage, paper mill and distillery effluent ( n = 5.81, 4.95 and 7.75 respectively), Fe and Zn in beverage industry ( n = 2.31 and 7.01). Vermicompost act as a strong buffer to neutralize the pH of the effluent. The pH of the filtrate came to be 7.8 for beverage and paper mill effluent and 5.8 for distillery effluent. EC of the filtrate increased to 4.0 mS/cm for beverage effluent, 6.1 mS/cm for paper mill effluent and 8.1 mS/cm for distillery effluent from its initial value of 2.0, 4.8 and 6.9 mS/cm respectively. The value of COD was 2.5 times less than their respective initial values. Vermicompost removed the high BOD of the industrial effluents and it came down to 174.0 mg/L for beverage industry, 260.0 mg/L for paper mill effluent and 5806.0 mg/L for distillery effluent from its initial value of 387.5 mg/L, l440.0 mg/L and 17200.0 mg/L respectively. TDS and TSS of the effluents respectively came down to 72.0 mg/L and 246.0 mg/L for beverage effluent, 210.0 mg/L and 230.0 mg/L for paper mill effluent and 206.7 mg/L and 105.7 mg/L for distillery effluent.

Three parallel mineral filters, each with a volume of 2550 cm3, were used for phosphate removal from natural swimming pool (NSP) water. Filters worked continuously in saturated conditions. Hydraulic loading rates (HLRs) were 15 m3/m2h, 15 m3/m2d and 5 m3/m2d for Filter 1 (F1), Filter 2 (F2) and Filter 3 (F3), respectively. In the middle of the length of the filter, an inspection hole was located for sampling the filtration material. Samples were collected on the 55th, 87th and 120th day of filter operation. The phosphate sorption capacity of materials sampled from the filters was significantly lower than the sorption capacity of the fresh material, with their values varying between filters (different HLRs) and sampling events. In the case of F3 (slow filter), a decreasing phosphate sorption capacity was observed along with the time of operation. However, filtration material sampled from filters F1 and F2 had a higher P sorption capacity at the end of the monitoring period (day 120th day) than at the time of second sampling (day 87th day). This may suggest that the biofilm which developed on the grains of the filter blocked the contact between reactive material (RM) and treated water. Breaking the biofilm due to a faster flow (F1 and F2) resulted in increased filter sorption capacity. The remaining material sampled from F1, F2 and F3 was dried and also tested for P sorption capacity. Results showed that air drying increased the P sorption capacity of material from below 50% up to 100% of initial value, which suggests that periodic drying of filters may be a simple option for the regeneration of filtration material. P-bounded forms in filters were also analysed and discussed.

A novel integrated system consisted of microbial fuel cell, aerobic bioreactor, and anoxic bioreactor (MFC-AB-ANB) was designed and constructed to investigate its potential for the treatment of slaughterhouses wastewater associated with power generation and nitrogen recovery. A biocathodic tubular type MFC was used in this study and was inoculated with freshly collected activated sludge. The MFC-AB-ANB system was continuously operated for 163 days. The results revealed that maximum efficiencies of COD removal, ammonium oxidation, nitrate reduction, nitrogen recovery, Columbic efficiency, and power generation were 99%, 99.3%, 100%, 100%, 13.37% and 162.55 mW/m2, respectively. A mathematical model was developed based on Nernst–Monod model coupled with nitrification-denitrification model to predicate and describe the removal of COD, ammonium, and nitrate during continuous operation of the system. Significant agreement between the predicted and experimental results was observed for the removal of COD, ammonium, nitrate, and power generation with determination coefficients of 0.9750, 0.95675, 0.95499, and 0.89897, respectively.

Aquaponics is the integration of recirculating aquaculture and hydroponic systems which is considered to be an innovative, eco-friendly and sustainable food production technology. In this study, a special design of hydroponic biofilter that integrated constructed wetlands and floating-raft rice hydroponics was constructed to treat the nutrient rich effluents from the intensive fishpond and to establish an aquaponic system on pond scale. The treatment efficiencies and food production potential of the new rice hydroponic biofilter was evaluated after determining the key operating parameters. As the results, overall nutrient removal efficiency was optimized at hydraulic load rate (HLR) of 0.58 m.d−1 and air-to-water ratio of 2:1. The average removal efficiencies of total ammonia nitrogen (TAN), total nitrogen (TN), total phosphorus (TP) and chemical oxygen demand (CODMn) from fishpond wastewater were in the range of 33.75–34.31%, 59.21–64.53%, 68.43–73.75% and 71.66–74.37%, respectively. Meanwhile, hydroponic rice grew well in the biofilter and gained a yield of 7 127 kg.ha−1. These results probably implied that the novel rice hydroponic biofilter exhibited efficient effluent treatment and presented as a viable alternative for the food production in a pond-scale aquaponics recirculating system.

Wood particle biofilters are being used for remediation of nitrate in watercourses but so far, have received little attention for the possibility of phosphorus (P) treatment. Phosphorus export in many agriculture and urban stressed watercourses however, is dominated by particulate rather than dissolved P and particulate P is potentially treatable by physical filtration. Five low cost, highly permeable media types, including woodchips, sawdust, bark mulch, corn cob chips and peastone, were tested in eight pilot scale biofilters over a six month period for their ability to remove suspended solids (TSS) and particulate P from turbid stream water. The biofilters were operated at high loading rates, with retention times averaging 1.9–4.2 h and achieved TSS removal averaging 85–97%. Excluding a 30 day startup period, seven of the eight biofilters removed an average of 53–64% of stream total P (TP) averaging 65.6 µg/L. The corn cob media provided lower TP removal (1%) because P leached from the media. These filters provided TP removal at hydraulic loading rates that were an order of magnitude higher than when similar media is used for nitrate remediation. These low cost filter media, with capacity for high loading rates, could offer a practical solution for P removal in urban storm water ponds, sewage lagoons and agriculturally impacted water courses.

Nowadays swine slurry management is a very important environmental issue. Sludge treatment reed bed systems are sludge treatment systems based on constructed wetlands. The present study characterizes via 16S rRNA gene high-throughput the bacterial communities contained in untreated swine slurry and treated swine slurry by means of mesocosm-scale sludge treatment reed beds receiving different slurry loadings. The bacterial community composition varied between the treated and untreated slurry, with a notable slurry loading influence also observed. Richness, diversity and ordination measurements of the studied communities evidenced profound differences between the untreated and treated swine slurry bacterial communities; and only slight differences among the treated swine slurry communities. Interestingly, the slurry loading allowed to define two groups: mesocosm communities residing in the highest hydraulic slurry loadings and other mesocosm communities. The pH value emerged as an important community composition, diversity and ordination predictor. The functional bacterial community composition was predicted through the in silico approach. Results confirmed that the main nitrogen cycle metabolic pathways were present in the mesocosm communities with ammonification and assimilatory nitrate reduction as the most commonly detected nitrogen pathways in treated swine slurry.

A prototype artificial wetland was designed to treat greywaters from the community of El Carrizo in Durango, Mexico, to remove the surfactants derived from used detergents. For this study, 6″ PVC tubes with a water depth of 40 cm were used, in which the water was replaced after 3, 8 and 15 days. Tezontle, gravel and agave fibre were used as supports, and Schoenoplectus americanus, which is an emergent aquatic plant, was used as biological material. The different levels of the factors resulted in 24 treatments, whose differences were validated with a factorial ANOVA of 4 × 2 × 3 with three repetitions. At the beginning and end of each period, it was determined the removal of detergents, oils and grease, total solids, total volatile solids, total suspended solids, changes in pH and electrical conductivity and toxicity of the effluent through bioassays with lettuce seeds. The results show that the best percentage removal of detergents (surfactants linear alkylbenzene sulfonates, LAS) of 90% was obtained with the agave fibre, with or without S. americanus, at a hydraulic residence time of 15 days; however, the treated water showed low seed germination indexes. This was followed by the gravel-S. americanus system, which had a removal percentage of 78% and showed decreases in all of the measured parameters and the lowest toxicity value on germination and root growth of Lactuca sativa. These characteristics define the optimal parameters for the implementation of artificial wetlands in the community of El Carrizo, Durango, Dgo., Mexico.

Since their inception in larger pond systems, the focus of anaerobic ponds has shifted from solids removal to optimising biogas production and reducing physical footprint to minimise land requirements. In this study, a horizontally baffled (HBAP) and vertically baffled (VBAP) anaerobic pond were compared. Distinct differences in the removal efficiency of COD fractions were observed, with particulate COD removal of 78% and 32%, and soluble COD removal of −26% and 19% in the HBAP and VBAP, respectively. A staged pond (SAP) was constructed through an HBAP placed upstream of a VBAP, with an additional HBAP used as a control (CAP). The SAP demonstrated superior biogas recovery potential over the control: methane production by the conclusion of the study was 6.09 and 9.04 LCH4 m−3 wastewater treated for the CAP and SAP, respectively. Methanogenic activity in the ponds was higher closer to the outlet, and hydrogenotrophic methanogenesis dominated over acetoclastic pathways.

A cost operative and favorable technology has been revealed for the removal of (COD, BOD and Oil & Grease) from oily industrial wastewater effluents. Batch scale studies for the biosorption potential of novel biosorbent Phragmites australis (Reeds). The study was supported at different constraints to obtain prime conditions of biosorbent dose, time of contact, pH, agitation speed and initial organic loads concentration. To dissect the propriety of the procedure and decided amount of organic loads removal, Langmuir and Freundlich isotherms were connected. The ideal estimations of contact time and agitation speed were found at 120 min and 150 rpm respectively. The ideal biosorption limits were seen at pH 7. Both pseudo-first and pseudo-second order models were connected and it was discovered that information fitting best to the pseudo-second-arrange active model. The outcomes demonstrated that Phragmites australis was an empowering adsorbent for the biosorption treatment of oily derivatives industrial wastewater.

In this study, wastewater blended from textile, distillery, and domestic sources at a corresponding volumetric ratio of 3:1:18, was treated using Lemna minor and Azolla filiculoides for 28 days in a batch system installed in a shade house. Analysis of variance between the two macrophytes showed no statistical differences in removals of all tested parameters (p

To demonstrate the feasibility of Enhanced Pond and Wetland (EPW) system for the treatment of Biological Trickling Filter (BTF) effluent, pilot-scale EPW systems were installed and operated in New Zealand climate conditions. The system consisted of: two High Rate Algal Ponds (HRAPs) followed by gravity Algal Harvesters (AHs), two Surface Flow Constructed Wetlands (SFCWs), and a Woodchip Denitrification Filter (WDF). The wastewater treatment performance of each treatment component was monitored fortnightly over six months (late autumn to winter) in terms of TSS, total and soluble BOD5, nutrients (N and P) and E. coli removal. Algal biomass production, algal harvest efficiency, and algal dominance in the HRAPs were also determined. The pilot-scale system maintained low final effluent TSS and BOD5 concentrations below 5 and 8 mg L−1 respectively, and achieved high removal of nitrogen (NH4-N: ∼95%; NO3-N: 77%), phosphorus (DRP: ∼65%) and E. coli (at least 3-log E. coli removal) throughout the experimental period. Particularly in autumn, the HRAPs achieved almost complete removal of both NH4-N (5.0 to

The need to expand marine fish production and improve the economic viability and sustainability of recirculating aquaculture systems led to the development of a zero-discharge, marine aquaponic system. In this study, water treatment capacity, nutrient cycling, and biomass production were evaluated in a prototype, commercial-scale marine aquaponic system that included a moving bed bioreactor (MBBR) for nitrification, a sand filter for solids removal and denitrification, and hydroponic plant beds. Red drum (Sciaenops ocellatus), two species of edible halophytes sea purslane (Sesuvium portulacastrum) and saltwort (Batis maritima), and organic solids, were successfully produced over a 9-month period. Extensive analysis of solids, organic matter, and nutrients (nitrogen and phosphorous) in water and plant biomass was used to develop detailed mass balances on the system. Simultaneous operation of the moving bed bioreactor (MBBR) and plant beds resulted in high ammonia removal rates, allowing the system to support a high fish biomass density (38.8 kg/m3). Passive denitrification was the main nitrate removal mechanism, contributing to approximately 59% of aqueous nitrogen removal. Conversion of a sand filter to a side-stream denitrification reactor resulted in removal of 17% of the daily aqueous nitrogen load and prevented nitrate accumulation in the system. In addition to fish and edible halophyte production, 34 kg of organic solids were harvested from the sand filter and provided to a commercial nursery that used the solids as a fertilizer. This study demonstrates that marine aquaponics is an effective way to simultaneously produce marine fish, edible halophytes, and fertilizer. Addition of biological MBBR and a denitrifying sand filter was shown to be beneficial in situations where there are space limitations for plant growth, unexpected plant losses, or to support high densities of fish.

Woodchip bioreactors are recognized as an effective best management practice in the Iowa Nutrient Reduction Strategy. This edge-of-field practice intercepts and removes NO3-N, thereby reducing the NO3-N concentration in tile drainage before being discharged into surface water. Actual NO3-N load reductions realized by woodchip bioreactors are impacted by bioreactor size, hydraulic retention time (HRT), and denitrification efficiency. A typical woodchip bioreactor in Iowa may have 0.07% bioreactor area with respect to treatment area, 4–8 h HRT, and 43% mean denitrification efficiency. Here, we explored the potential of using electrically stimulated woodchip bioreactors to achieve greater NO3-N removal, and estimated the costs of this approach. Batch experiments were conducted to determine the denitrification efficiency of electrically stimulated and traditional woodchip bioreactors at different HRTs and current densities. The resulting data was used to model costs and denitrification efficiency in 75 scenarios, covering a range of bioreactor volumes, HRTs, current densities, and annual durations of electrical stimulation periods. For each scenario, we reported the estimated annual NO3-N load reduction and NO3-N removal cost. We found that electrically stimulated woodchip bioreactors may remove an additional 37–72% annual NO3-N load than a traditional woodchip bioreactor, but at the expense of higher NO3-N removal costs, which were increased by 138–194%.

Among different decentralized wastewater treatment systems, constructed wetlands are particularly robust, reliable and cost-effective technologies. However, traditional treatment wetland designs have a limited capacity to remove total nitrogen. The recirculating vertical-flow constructed wetland (RVFCW) system is a novel modification of the vertical flow wetland (VFW), allowing for increased denitrification by circulating the nitrified effluent back into a recirculation tank, where it is mixed with primary treated wastewater. Microcosm experiments were conducted to investigate the effects on nitrogen removal of mixing recirculated VFW effluent with raw wastewater after different degrees of primary treatment, with and without attached growth media. The results show that the inclusion of attached growth media in the first chamber of the recirculation tank resulted in enhanced total nitrogen removal. The microcosms that contained a mixture of raw wastewater and VFW effluent showed denitrification efficiency of 83% after 48 h of contact time. An increase in the denitrification efficiency (up to 99.5%) was observed in microcosms that also contained attached growth media. The majority of nitrate-N (NO3-N) removal was achieved in the first 24 h. Inclusion of media increased the denitrification efficiency after 48 h contact time from 36 to 93% and from 31 to 88% in microcosms containing VFW effluent mixed at a ratio of 3:1 with wastewater after 1 and 2 days residence time in a septic tank respectively. It was inferred that the lower the degree of pre-treatment of wastewater into which the recirculated VFW effluent was mixed, the greater is the denitrification rate and thereby the lower TN concentration in the effluent.

Green roofs are an effective green infrastructure tool to reduce stormwater runoff in cities, but their considerable weight is a constraint on widespread uptake. Consequently, lightweight green roof substrates with high water retention are desirable. Biochar addition to green roof substrates may reduce green roof weight and improve stormwater retention by increasing water holding capacity. However, the effects of biochar on substrate properties can vary due to differences in biochar particle size and amendment rate that influence substrate porosity and therefore substrate water and air-content. Additionally, differences in the feedstock used to produce biochar also mean that biochars are highly variable in their internal porosity, affecting their water retention and weight. To determine how biochar particle size, amendment rate and feedstock density influence substrate water retention, bulk density, air-filled porosity and infiltration we tested substrate properties of a scoria-based green roof substrate mixed with two different biochars contrasting in feedstock type, at three different biochar particle size fractions (coarse 2 mm – 10 mm, fine

This study attempted to determine an efficient flocculant that was used for the recovery of microalgal species, namely Scenedesmus. The biomass was grown in a pilot-scale raceway pond receiving domestic wastewater discharges. The microalgae achieved treatment efficiencies of 76.5% NH4+-N, 83.1% PO43−-P, 73.9% biological oxygen demand (BOD), and 42.8% chemical oxygen demand (COD). During microalgal harvesting, the highest biomass recoveries of 99.0%, 97.5%, and 96.5% were obtained by alum 300 mg/L at pH 7, chitosan 100 mg/L at pH 7, and cationic polymer 10 mg/L at pH 10, respectively. The protein, carbohydrate, and lipid yields of polymer-harvested biomass were 28.0%, 12.4%, and 17.4% (dry cell weight), respectively, which were higher than those obtained when applying either alum or chitosan flocculants. Moreover, the cationic polymer provided no detrimental effects on the fractions of fatty acids derived from the harvested microalgal cells. The microalgal biomass subjected to flocculation by either polymer or chitosan were entire and intact, whereas the lysis of cells was noticed during the alum flocculation process.

The present research investigated the efficiency of an integrated system for the treatment of wastewaters generated at a rural property located in the city of Vera Cruz do Sul, southern Brazil. The integrated system was composed of an anaerobic unit (UASB/AB), 4 subsurface constructed wetlands (SSFCWs), and two photoreactors (UV-254 nm). The evaluation of the performance was based on the reduction of the load parameters and mainly on the detoxification of the wastewaters. The ecotoxicological analysis included short-term assays with the microcrustacean Daphnia magna whereas the cytogenetic potential of the wastewaters was assessed by using the Allium cepa test system. On the one hand, the raw wastewaters presented a strong pollution potential due to high COD, BOD5, TKN, N-NH3 and total P values. On the other hand, the effluents treated by the integrated system showed high reductions of the abovementioned parameters and fully attend the Brazilian and International legal requirements. Furthermore, the treated wastewaters presented a complete absence of the acute ecotoxicity (100%) as well as significant reductions of the cytotoxicity, genotoxicity, and mutagenicity when compared to the raw wastewaters. Therefore, the investigated system can be considered an interesting low-cost sanitation alternative, especially for wastewaters produced in rural areas, where decentralized systems are more suitable. Besides, the results obtained in the present work demonstrate the importance of including toxicity analysis in the monitoring of waters and wastewaters in order to obtain a broader evaluation concerning the efficiency of different treatment systems.

The main aim of our study was to construct a two-stage vertical flow constructed wetland (VFCW) system to treat single household raw sewage water in India under tropical climate. For selecting the plant species different sets of lab experiments were carried out. Two different plant species (Typha angustata and Canna indica) were considered for their nutrient removal efficiency and biochemical methane potential (BMP) efficiency. Drum experiments were conducted to select the most suitable species for the constructed wetland. Batch assays were conducted in 100 ml bottles in order to determine BMP of plant biomass. The overall nutrient removal efficiency was the same in case of both the plant species that were tested. Typha angustata had been selected for planting in the single household wetland system as it is found in the natural wetlands of Goa and they have higher BMP than other species. The nutrient removal of pilot scale VFCW was monitored at two hydraulic loadings at 0.150 m/day and at 0.225 m/day. The removal of Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), Total Kjeldahl Nitrogen (TKN), Ammoniacal Nitrogen (NH3-N), Total Phosphorous (TP), Total Dissolved Solid (TDS) and Total Volatile Solids (TVS) at 1st stage was 64%, 65%, 15%, 21%, 34% and 54% and for the 2nd stage reactor it is 90%, 88%, 50%,52%, 58% and 71% respectively on an average. After changing HLR (hydraulic loading rate) to 0.225 m/day the removal of COD, BOD, TDS, TVS, TKN and NH3-N at 1st stage was 61%, 62%, 33%, 40%, 35% and 58% and for the 2nd stage reactor it is 90%, 84%, 61%, 64%, 47% and 82% respectively on an average. As the loading rate increases there is no change in the treatment efficiency of TKN and NH3-N treatment efficiency increases. However marginal decrease in the treatment efficiency of COD and BOD of the system was observed. The overall footprint of the system got reduced from 1.5 m2 per person to 0.79 m2 per person under Goan climatic conditions.

Green roofs are a key component to building sustainable cities because of their multiple environmental benefits, but without the proper level of care, the leachate from green roofs might contain pollutants and become a new nonpoint pollution source in urban areas. Because its leachate quality is affected by the substrates and plants used, the objective of this study is to evaluate the effects of the substrates and plants with the aim of improving green roof applications. This study tested 3 materials – normal cultivated (C) substrate, commercial green roof (L) substrate, and mixed C and recycled glass (R) substrate – with a focus on using recycled glass materials in the green roof system. Recycled glass is a lightweight and porous material that improves pollutant absorption and water quality purification. Three different types of plants were tested: a sedum, a fern, and a shrub. Therefore, this study evaluated 9 combinations, each with 3 replicates. The differences in the substrates exerted significant effects on the chemical oxygen demand (COD) and phosphorous (P) concentrations. The nitrogen (N) concentrations were affected by differences in both the substrates and the plants. The changes in the observed water quality with time implied that compact substrates and mature plants reduced pollutant concentrations, except for N concentrations, in the outflow. The L substrate contained high levels of nutrients, and the plants grew better in this substrate than in the other two substrates; however, the L substrate also produced higher pollution concentrations. The R substrate, with recycled glass, performed well in the neutralization of acid rain but did not significantly reduce the levels of other pollutants. To enhance the purification ability of the recycled glass, the mixing ratio between the recycled glass and organic substances and the placement in the substrate are important factors.

Woodchip denitrification bioreactors are an important edge-of-field practice for treating agricultural drainage; however, their ability to filter microbial pollutants has primarily been explored in the context of wastewater treatment. Upflow column reactors were constructed and tested for E. coli, Salmonella, NO3-N, and dissolved reactive phosphorus (DRP) at hydraulic retention times (HRTs) of 12 and 24 h and at controlled temperatures of 10 and 21.5 °C. Influent solution was spiked to 30 mg L−1 NO3-N, 2–8 × 105 E. coli and Salmonella, and 0.1 mg L−1 DRP. Microbial removal was consistently observed with removal ranging from 75 to 78% reduction at 10 °C and 90–96% at 21.5 °C. The concentration reduction ranged from 2.75 to 9.03 × 104 for both organisms. HRT had less impact on microbial removal than temperature and thus further investigation of removal under lower HRTs is warranted. Nitrate concentrations averaged 96% reduction (with load removal of 14.6 g N m−3 d−1) from 21.5 °C columns at 24 HRT and 29% reduction (with load removal of 8.8 g N m−3 d−1) from 10 °C columns at 12 HRT. DRP removal was likely temporary due to microbial uptake. While potential for removal of E. coli and Salmonella by woodchip bioreactors is demonstrated, system design will need to be considered. High concentrations of these microbial contaminants are likely to occur during peak flows, when bypass flow may be occurring. The results of this study show that woodchip bioreactors operated for nitrate removal have a secondary benefit through the removal of enteric bacteria.

A single chamber membrane-less air cathode microbial fuel cell coupled constructed wetland (MFC-CW) was constructed to treat nitrobenzene-containing wastewater and generate electricity simultaneously. Three devices of blank control (CK), microbial fuel cell (MFC) and MFC-CW were investigated. The inherent relationship between substrate degradation and electricity generation were evaluated by the electronic characteristics. The maximum voltage of MFC-CW was obtained at the electrode spacing of 13 cm. The maximum power density of MFC and MFC-CW were 0.59 and 1.53 mW/m2 respectively. The maximum nitrobenzene removal rate of 92.89% was attained in the MFC-CW when the concentration ratio of nitrobenzene to chemical oxygen demand (COD) was 1:16 with hydraulic retention time at 24 h. The COD removal rate was between 67.92% and 78.30%, and the MFC-CW was efficient for COD degradation.

Water with excessive nutrients are continuously released into water bodies, the resulting eutrophication causes public health, environmental, and economic problems. Phosphorus (P) impairment of fresh surface waters is a major concern in the USA and worldwide. The aim of this study is to use a bench scale P removal system that utilizes electrocoagulation (EC) to address this water quality problem. This study examined the effects of treatment parameters (initial pH, initial conductivity, power input, and initial P concentration) on the ability of the EC process to remove P in solutions with initial P concentrations less than 2 mg/L. It also investigated the ability of EC to reduce concentrations of P in surface water and treated wastewater. P concentrations in phosphate solutions, surface water, and wastewater effluent were reduced by 99% in under 60 min. The removal efficiency was demonstrated to be directly proportional to the conductivity and power supplied.