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Nanoparticles (NPs) are relevant in several industrial applications due to their peculiar properties with respect to their bulk precursor material. Hence, there is a growing need to develop novel technical solutions to synthetize such NPs by simple, eco-friendly, and cost-effective processes. In this regard, the authors have recently proposed a strategy for the safe and sustainable production of NPs involving a mechanical refining using magnetic agitation in wet-operating stirred media, which minimizes the NPs air dispersion and improves the control over the final product specifics. However, the magnetic agitation poses heavy limits of applicability in the case of synthesis of ferromagnetic NPs. In the present contribution, an alternative device configuration developed to overcome this limitation is investigated though a numerical approach. Discrete element method (DEM) simulations are performed to model the grinding and primary particles collisions and to clarify the effect of the parameters involved in both process setup and operation. The results are reported in terms of frequency and velocity of collision and compared to those of the standard device configuration to derive useful information about the functioning and capabilities of the novel system. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the suitability of using woodchips as a carbon source for denitrification in intermittently operated household slow sand filters. This was accomplished through a series of batch and column experiments where fishpond bacteria were used to inoculate the reactors, and the resulting nitrate and nitrite concentrations observed over 24 h. Results from batch experiments in 100 mL serum bottles loaded with 0.5, 3 and 5 g of woodchip material, and 200 mg/L nitrate feed achieved 78%, 100% and 90% nitrate removal respectively. Nitrite concentrations in the batch reactors were 55, 0 and 98 mg/L after 24 h. A second set of batch experiments where 3 g of column sand was used as an inoculum showed a drop in nitrate from 200 mg/L to 182 mg/L. Three columns were constructed and fed intermittently with 3 L of nitrate contaminated water daily. The filter columns consisted of a woodchip only column, a sand only column and a mixed sand and woodchip column. After allowing them to stand for 24 h after being inoculated with denitrifying bacteria, the three columns were able to achieve complete denitrification within the 24 h filter run for a 50 mg/L nitrate feed. Nitrite production peaked at 2.4mg/L during this filter run. For a 200 mg/L nitrate feed, complete denitrification was achieved in the woodchip only column, effluent from the mixed and sand columns measured at 45 and 156 mg/L of nitrate, and 8 and 4 mg/L of nitrite respectively. A heterotrophic plate count gave counts of 9x10³, 4.8x105, 9.9x104 and 3.3x105 cfu/mL for the feed, woodchip, sand, and mixed effluent filter streams at 200 mg/L nitrate feed. [ABSTRACT FROM AUTHOR]

Using slow sand filters on a small scale, their decontaminating effect was tested. The work was carried out with the objective of eliminating the contamination of the effluents from the oxidation lagoons of two sugar mills "Carlos Baliño" and "Melanio Hernández". The effluents were taken in the central region of the country (Santo Domingo, Villa Clara and Tuinicú, Sancti Spíritus). The decontaminating effect of effluents from oxidation ponds after their passage through a slow sand filter in cascades was tested for different investigated treatments. The effluents were diluted in distilled water in the following proportions: T1 (10%), T2 (25%), T3 (50%), T4 (75%), T5 and T6 (undiluted). In the effluents, the following were determined: their physicalchemical and microbiological characteristics, before and after their passage through the slow sand filters. In most of the effluents evaluated, both their physical-chemical characteristics and the microbial load showed a notable reduction; obtaining values below the indicators allowed by current Cuban standards (NC-27: 2012; NC-1095: 2015 and NC-855: 2011). [ABSTRACT FROM AUTHOR]

From 2014 to 2020, a full-scale horizontal well was operated to investigate the performance of full-scale riverbank filtration (RBF) in the Nakdong River in Korea, which is significantly impacted by the effluents from sewage treatment plants. In this study, an individual lateral full-scale horizontal collector well was investigated for the first time in Korea, and its performance was determined based on the turbidity and levels of iron, total nitrogen, dissolved organic matter, and four selected trace organic contaminants (TrOCs) (tebuconazole, hexaconazole, iprobenfos, and isoprothiolane) in the RBF and Nakdong River. The turbidity of the river was high with an average of 10.8 NTU, while that of the riverbank filtrate was 0.5 NTU or less on average. The average dissolved organic carbon (DOC) concentrations were 2.5 mg/L in the river water and 1.4 mg/L in the riverbank filtrate, which indicated a 44% reduction in DOC content during the RBF. Out of the 10 laterals, 8 laterals exhibited similar levels of iron, manganese, total nitrogen, DOC, and total hardness, electrical conductivity, and turbidity. The characteristics of the remaining two laterals were different. Because the groundwater inflow was relatively low (<10%), the laterals were contaminated by agricultural land use before the installation of the RBF. This is the first study to report changes in water quality according to individual laterals in a river affected by wastewater effluents. The filtration unit exhibited more than 90% removal rates for tebuconazole and hexaconazole. However, the removal rate for iprobenfos was approximately 77%, while that for isoprothiolane was 46%. The four selected TrOCs in this study were not detected in the groundwater. We found that some organic micropollutants were effectively removed by the RBF. [ABSTRACT FROM AUTHOR]

In this study, a novel hybrid treatment system was designed to increase the removal efficiency of petroleum refinery wastewater. The hybrid system is a pilot scale including an activated sludge combined with a rotating biological contractor (RBC) and sand filter. Four vertical rotating polyurethane disks in the aeration tank combined activated sludge-rotating biological contactor pilot. The influent wastewater for this system was the effluent from the DAF unit in the Shahid Tondgooyan Oil Refining Co's wastewater treatment plant. The rotation rate of disks and retention time has been evaluated for their impact on the removal efficiency of total dissolved solids (TDS), dissolved oxygen (DO), pH, total suspended solids (TSS), turbidity (TU), chemical oxygen demand (COD), biochemical oxygen demand (BOD), ammonia (NH3). According to the results, enhancing the rotational speed of disks (from 4 rpm to 8 rpm) and increasing the retention time (from 6 hours to 10 hours) can improve COD, NH3, TSS, BOD5, TU, TDS, and oil removal efficiency of this system to 100, 98.52, 84.21, 100, 99.25, 13.32 and 100% respectively. Escalating the rotational speed beyond 8 rpm had reverse effects on the performance of this hybrid system. The rotational speed of 8 rpm and a retention time of 10 hours were the optimum conditions for removing the abovementioned parameters. It is worth mentioning that the high TU removal efficiency of the system was due to the presence of a sand filter. This system performed well in removing pollutants compared to other biological wastewater treatment systems. [ABSTRACT FROM AUTHOR]

This paper describes a simple generic model designed to predict membrane fouling in municipal wastewater (MWW) treatment. The work was conducted using data from a direct membrane filtration demo-system (middle/long-term filtration periods of about 35 – 124 days) to calibrate the model. Two influents were treated by the demo-system: raw pre-treated MWW and primary settler supernatant from a full-scale MWW treatment plant. A resistance-in-series mathematical model structure was proposed considering fouling due to two different mechanisms: persistent cake layer formation (from suspended material) and pore blocking (from soluble and colloidal compounds). The proposed model represented transmembrane pressure dynamics at different operating solids concentrations (around 1, 2.6, 6 and 11 gL−1) using 7 model parameters, achieving 7–28 mbar differences between the experimental data and model predictions in all cases (calculated as the root mean square error). The model was also able to match the results from two different influents (raw MWW and primary settler supernatant) by modifying 3 of the 7 parameters while low uncertainties were obtained in long-term filtrations, demonstrating its robustness. This model thus provides a good potential to generate reasonable membrane fouling predictions while its simple and open structure makes it easy to implement with complementary materials. Further research will be carried out to enhance the model's precision and validate its potential for optimizing filtration and fouling control processes. [Display omitted] • Irreversible fouling from direct sewage filtration was modeled. • Proper predictions are obtained under a simple structure (7 calibration parameters). • Solids (cake layer) and SMP (pore blocking) effects were considered simultaneously. • Two influents were modeled: raw sewage and the primary settler supernatant. [ABSTRACT FROM AUTHOR]

Effective application of micro-nano copper particles in elimination of the pathogenic microorganisms in the water remains a challenge. In this study, an optimum structural design was adopted in mathematical models to improve the efficiency of sewage filtration, and polycaprolactone/copper scaffold (PCs) was fabricated through a 3D printing method. The result shows that the micro-nano copper particles were physically embedded into the polycaprolactone scaffolds. In addition, the antibacterial efficiency of PCs against E. coli and S. aureus was up to 100% and the antibacterial performance could be remained in sewage filtration (copper: polycaprolactone = 1:2). The results suggest that PCs is a good candidate for application in the sewage treatment. [ABSTRACT FROM AUTHOR]

A laboratory study was undertaken in a rectangular filtration chamber having length, width and height as 200 mm, 160 mm and 1200 mm, respectively. Each filter consists of 15 cm thick boulder layer of size 20–40 mm and 15 cm thick gravel layer of size 4.75–10 mm and 10 cm thick. The thicknesses lower course sand (CS) layer of size 0.600–1.18 mm and 10 cm thick upper CS layer each of size 0.425–0.600 mm, 0.300–0.425 mm and 0.150–0.300 mm is placed separately in filters T1, T2 and T3. The influent sediment load prepared by using 0.75–0.15 m soil in terms of concentration as 250, 500, 1000, 1500, 2000, 2500 and 3000 mg/l was used for checking the performance of the filtration system. Various important parameters such as recharge rate, clogging time and removal efficiency of double sand layer filtration system were estimated. The performance of the filter T3 used in present study has also shown better results as compared to filters used in the past for the purpose of artificial recharge of ground water. The proposed filter with treatment T3 is found to be cost effective due to smaller size of the filter as compared to the past studies as well. [ABSTRACT FROM AUTHOR]

In order to investigate the fouling mechanism in dynamic membrane (DM) formation, and filtration performance in domestic sewage treatment at an ambient temperature ranging from 24°C to 36°C, an anaerobic dynamic membrane bioreactor (AnDMBR) was monitored. Hydraulic retention times applied were 8 and 12 h, under permeate fluxes of 1,755 and 1,170 L m–2 h–2 in phases I and II, respectively. In both phases, after a 10% reduction in permeate flux, backwashing was performed. This allowed a prolonged filtration of 84 d for phase I and 76 d for phase II. The total resistance to filtration was in the magnitude of 1011 m–1, implying excellent filterability by the DM, and energy- saving potential for the AnDMBR system. The system had good treatment performance, achieving average volatile fatty acid reduction of 53%, total chemical oxygen demand (COD) removal efficiencies of 84%, soluble COD of 72%, and color of 80%; being able to remove 94% of suspended solids, and producing an effluent with low turbidity (17 NTU). The biogas measured in the system was 154 N mL g–1 COD removed, which represents 35% of its theoretical value, which means that most of it left in dissolved form with the effluent due to supersaturation. The predominant fouling mechanism in DM formation in all permeates fluxes tested was cake filtration, with the main cause being the concentration of inoculum sludge. This confirms the prominence of DM formation during filtration and high solid–liquid separation. [ABSTRACT FROM AUTHOR]

The paper discusses the use of multiclustering statistical analysis in the assessment of domestic wastewater filtration effectiveness. Calculations included data collected over four months of experiments with using waste as filling material of vertical flow filters for domestic sewage treatment. The effectiveness of pollutants removal was analysed in case of mechanically shredded waste in the form of PET flakes, PUR foam trims, shredded rubber tires and wadding. The organic compounds (CODcr, BOD5) removal, suspend solids, biogens (as NH4+, PO43−ions) and oxygen saturation changing compared with sand filling was analysed. Multiclustering statistical analysis allowed to divide pollutants removal efficiency of analysed materials into 3 clusters, depending on the hydraulic loading. The first group consisted in quality parameters of treated sewage: the highest reduction of BOD5 and NH4-N. It included the values of quality parameters and indicators for the filtrates obtained at the lowest hydraulic load from columns filled with 60 cm of rubber tires or sand. The second group comprised the results for fillings containing foam, PET and rubber tires (the other hydraulic loads). It featured the highest reduction of total suspended solids and PO43−. Removal of easily biodegradable organic compounds was at a similar level in both cluster groups. The filter filled with polyester waste (wadding), which was as effective as 30 cm layer of sand, and the filters filled with 60 cm of sand working at the highest hydraulic load. Third group showed the lowest values of parameters and indicators for analysed filtrates.

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Nature-based solutions, such as ConstructedWetlands (CWs), for the treatment of industrial wastewater can be more efficiently operated making use of online monitored parameters as inlet/outlet flows and concentrations for specific substances. The present study compares different datasets acquired in a two-and-a-half-year-long period by normal laboratory methods and also from a specific COD/BOD sensor installed at a winery CWs wastewater treatment plant in Tuscany, Italy. The CW wastewater treatment plant (WWTP) is composed of: equalization tank (70 m³); French Reed Bed (1200 M²); horizontal subsurface flow (HF) CW (960 M²): free water system (850 M²); optional post-treatment sand filter (50 M²); and emergency recirculation. The obtained average performances for this last period are for COD 97.5%, for MBAS 93.1%, for N-NO2-84.7%, for NO3-39.9%, and for TP 45.5%. The online sensor has shown excellent performance in following the COD concentration patterns along the observed period. The qualitative and quantitative validity of the online sensor measurements has been assessed by statistical analysis (t-test) and reported in the paper. Online data, acquired every 30 min, availability is of extreme importance for the CW system performance optimization, for understanding the behavior of theWWTPin different operative scenarios, and finally for driving the powering on or off eventual process enhancement tools. [ABSTRACT FROM AUTHOR]

The combination of anaerobic pre-treatment and conventional aerobic technologies in a single compact unit has the potential to afford practical, sustainable and low-cost systems for the decentralized treatment of sewage. The aims of the present study were (i) to determine the efficiencies of a singlefamily compact (SFC) and a multi-family compact (MFC) station in removing organic matter from domestic sewage, and (ii) to investigate the behavior of aerobic intermittent sand filters (ISFs) regarding nitrification. The SFC station consisted of an upflow anaerobic sludge blanket reactor, an anaerobic upflow bed filter and an aerobic ISF, while the MFC station comprised a septic tank and two ISFs. The mean efficiencies for the removal of total chemical oxygen demand, total suspended solids and total Kjeldahl nitrogen were, respectively, 90, 93 and 75% for the SFC and 87, 91% and 74% for the MFC with ISFs operated at hydraulic loading rates of 380 L.m-2.day-1. The sand filters produced helminth-free effluents that complied with World Health Organization recommendations for water intended for agricultural reuse, although the geometric mean of E. coli counts (104 CFU.100 mL-1) was somewhat high, implying that the treated water was appropriate for irrigation in low-tech agriculture. [ABSTRACT FROM AUTHOR]

Plant filtering techniques have proved to be appropriate solutions in the treatment of wastewater. In addition, the effluents can be re-used in water-deficient areas, in urban settings as well as in rural agricultural areas. The influent from the secondary black water pilot scale filtration basins (RALBI) was treated during a six-month study. The study shows the elimination of different pollutants from black water effluents with the effectiveness of 46.9–63.26% COD and 31.72–60% of the NH 4 + concentrations. We also tested the performance of Arundo donax on the adsorption of nitrogen compounds. The rate of COD removal for the control was 0.0185 gCOD/m2/d and 0.012 gCOD/m2/d for the planted filters, while the mean loading rate of the influent was 0.317 g/d. The rate of NH 4 -N removal for the control was 0.0152 gNH 4 -N/m2/d and 0.0127 gNH 4 -N/m2/d for the planted filters, while the mean loading rate of the influent was 0.271 g/d. Then, a concentration of 101.77–176.44 mg/L of nitrate was measured in the treated effluent. In addition, meaningful reduction of fecal coliforms and streptococci was achieved and reached over 95%. The quality of treated effluents has shown that the use of planted filters as a post-treatment stage is an efficient and inexpensive technology for the treatment of wastewater in small urban and rural communities. [ABSTRACT FROM AUTHOR]

This article outlines the life and career of H.A. (Bert) Hawkes, who has been referred to as one of the founders of field ecology, due to the work he conducted in the late 1940s and 1950s, investigating the fly nuisance emanating from biological filters. Following an overview of his life, there is a focus on his core research, carried out over a period of some 50 years, on two aspects of river pollution control—the prevention of pollution by sewage biological filtration and the monitoring of river pollution by biological surveillance. [ABSTRACT FROM AUTHOR]

Continuously flushing moving bed sand filter was operated in pilot scale for phosphorus (P) and nitrogen removal with simultaneous particle removal. The wastewater tested was either final effluent from a municipal wastewater treatment plant (WWTP) with nitrogen removal in moving bed biofilm reactors (MBBRs) followed by coagulation and dissolved air flotation (DAF) for P and suspended solids (SS) removal, or different mixtures of this final effluent and effluent from the MBBR-stage. The study focused on the applicability to achieve low total phosphorus (TP) concentrations (below 0.1 mg/L) and suspended solids concentrations (below 10 mg SS/L), plus good denitrification (removal rate over 750 g NO3-N/m³-d), by treating wastewater having variable concentrations of TP (from 0.19 to 7.3 mg/L), SS (from 3 to 169 mg/L) and total nitrogen (from 8 to 27 mg/L). The target effluent TP limit was easily achieved when adding coagulant to WWTP effluent. With correct coagulant dose (Al/TP-molar ratio >4) and good particle removal the target effluent TP could also be reached when treating mixed WW with fairly high influent TP. Very high denitrification rates were achieved with adequate influent P concentration and external carbon source. Low denitrification rates were observed when limited by low concentrations of biodegradable carbon and phosphorus. [ABSTRACT FROM AUTHOR]

The objective of this study is to synthesize previous research findings from bioretention experiments and identify design features that lead to the best performance of bioretention pollutant removal with a data-driven approach. A bioretention database was built from 79 bioretention publications, composed of 182 records of bioretention cells with their design features and the corresponding pollutant removal efficiency data. Non-parametric correlation analysis, multiple linear regression (MLR), and decision tree classifiers were applied to investigate the relationships between bioretention design features and pollutant removal efficiencies. Non-parametric statistics and MLR results indicated that bioretention surface area, media depth, the presence of an internal water storage (IWS) layer, soil composition, and vegetation cover are all significantly correlated with pollutant removal efficiencies. The impacts of design features are significantly different under different climate and inflow conditions. Decision tree classifiers showed that non-vegetated bioretention cells with sand filter media generally have higher than 80% total suspended solid (TSS) mass removal efficiencies; bioretention cells with minimum organic matter and greater than 0.58 m soil media depth tend to remove more than 51% of total nitrogen (TN); and vegetated bioretention cells with minimum organic matter remove more than 67% of total phosphorus (TP). The overall accuracy of decision tree classifiers in the test set is around 70% to predict TSS, TN, and TP mass removal efficiency classes. This study suggests that the data-driven approach provides insights into understanding the complex relationship between bioretention design features and pollutant removal performance. Image 1 • Bioretention BMPs with sandy media, a mulch layer, and monocots or no vegetation improve TSS removal efficiencies. • Bioretention BMPs with sandy loam soil, an internal water storage (IWS) layer, and monocots improve heavy metal removal efficiencies. • TN and TP removal is more effective in bioretention cells with a deeper soil layer depth, monocots, and minimum organic matter. The presence of IWS significantly improves TN removal efficiencies. • A data-driven approach is promising in providing helpful bioretention design suggestions. [ABSTRACT FROM AUTHOR]

BACKGROUND: Pathogenic microorganisms at the effluents of treatment plants entail a potential risk to public health. Enteric viruses such as adenoviruses (AdVs) and enteroviruses (EVs) are responsible for many waterborne diseases. Wastewater treatment methods eliminate successfully the load of indicators but other pathogens such as viruses have been detected in high concentrations at the effluents of wastewater plants. In this perspective, two constructed wetlands (CWs) systems (S1 and S2) were employed and fed with primary wastewater. S1 consists of a free water surface (FWS) wetland and a horizontal subsurface flow (HSSF) wetland working in series, while S2 consists only of the HSSF. Also, both systems included a sand filter (SF) after the HSSF. RESULTS: Results showed that these low‐cost systems are capable of eliminating effectively the bacterial indictors (total coliforms, Escherichia coli, Enterococci) achieving removal rates of almost 99% for S1 (3.2–4 Log units) and 89–98% for S2 (1.9–2.7 Log units). Regarding viruses, AdVs, EVs and phages were detected at all sampling points and during all seasons, and they were only partly removed in S1 and/or S2. For example, the virus load was decreased by 2.5 Log units for AdVs and 3.4 Log units for EVs in the case of S1, while the respective values were 4.3 and 1.9 Log units for S2. CONCLUSIONS: Generally, CWs eliminated successfully the bacterial load, while the remaining virus load was significant, thus strengthening the argument that viruses could be a reliable indicator for fecal contamination. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The present paper aims to introduce a novel and environment-friendly sludge dewatering method based on the osmotic technique, and to examine the efficiency of this method from macro- and micro-points of view. Intact sample, taken from the primary settler of a local wastewater treatment plant in Guangzhou (China), was firstly dewatered by mechanical methods (i.e. vacuum filtration and centrifugation), then by the osmotic technique. Macroscopic experimental results show that: the vacuum filtration and centrifugation can only dewater the sludge from 94.5 to 78.3% and to 78.8%, respectively, whereas, using the osmotic technique, water content of the sludge can be decreased to 44.2% in 12 h and to 35.9% in about two days. The micro-structure, obtained by scanning electron microscope (SEM), shows that: the sludge samples after vacuum filtration and centrifugation have a porous structure and water can be drained either through the cracks that have been developed under the vacuum pressure or by the micro-pores of several micrometers that have been created under the disturbance of the centrifugal force; on the other hand, in the case of the osmotic technique, the samples show a much denser structure, where both the macro- and micro-pores are significantly decreased or even closed at high concentration of the polyethylene glycol (PEG) solution. At last, the future application of the osmotic technique in practice is discussed from the viewpoints of deep dewatering and energy consumption. [ABSTRACT FROM AUTHOR]

The use of surface and recycled water sources for irrigation can reduce demand on critical groundwater resources. Treatment or mitigation may be necessary for the use of these alternative water sources in order to reduce risk associated with microbial pathogens present in the water. In this study, the efficacy of a zero-valent iron (ZVI) sand filter was assessed for the reduction of Listeria monocytogenes and Escherichia coli in surface water. Water recovered from an agricultural pond was inoculated with E. coli TVS353 and an environmental L. monocytogenes isolate at 7 Log 10 CFU/mL and horizontally filtered over a six-month period through a PVC pipe filter, filled with 35%:65% (volume:volume) ZVI:sand or sand alone. Filtered water was used to irrigate lettuce and bacterial persistence on lettuce leaves was determined for 7 days post-irrigation. Both ZVI:sand-filtered water and sand-filtered water contained significantly (p < 0.005) lower levels of E. coli and L. monocytogenes compared to initial unfiltered inoculated water. Population reductions of E. coli and L. monocytogenes were comparable after sand filtration. However, ZVI:sand filtration resulted in significantly greater population reductions of L. monocytogenes (P < 0.05) compared to E. coli. Populations of E. coli on leaves of lettuce plants irrigated with ZVI:sand-filtered water were not significantly lower than populations on plants irrigated with sand-filtered irrigation water over the 7-day period. However, populations of L. monocytogenes on lettuce leaves irrigated with ZVI-treated water were significantly lower than counts on plants irrigated with sand-filtered irrigation water on days 3 and 4 post irrigation (p = 0.052 and p = 0.042 for days 3 and 4, respectively. The differences observed in reductions of L. monocytogenes and E. coli by ZVI filtration is due to the differing effect that ZVI disruption has on Gram-positive and Gram-negative cell walls and membranes. ZVI- sand filters show promising results as an inexpensive on-farm technology for the mitigation of enteric foodborne bacterial populations in pond water over a six-month period. • ZVI-sand filters are useful for remediation of irrigation water of poor microbiological quality. • L. monocytogenes was removed by ZVI-sand filters more significantly compared to E. coli. • Bacterial survival on a plant leaf surface is impacted by previous exposure to a ZVI-sand filter. [ABSTRACT FROM AUTHOR]

• RAS provided conducive environment for E. coioides and T. mookalee maturation. • Round the year spawning of E. coioides and T. mookalee were achieved. • Economics reflected a payback period of less than a year and an IRR of more than 100%. Tropical and subtropical climatic conditions in India present an ideal and unique opportunity for being the leader in tropical marine finfish aquaculture. However, the problem persist due to non-availability of marine finfish seed for the culture. In response to this problem, broodstock development of different tropical marine finfishes for seed production was started. The present study was undertaken to design a recirculating aquaculture system (RAS) and studying their performance in managing the various water quality required for the marine finfish broodstock development and breeding. The design of RAS, developed in the present study, included a broodstock tank, egg collection chamber, electrical pump, rapid sand filter, venturi type protein skimmer and biological filter. Two RAS were designed, one was stocked with a demersal fish species, orange spotted grouper (Epinephelus coioides) and the other was stocked with a pelagic fish species, Indian pompano (Trachinotus mookalee) at the rate 1 and 0.5 kg/m3 with a sex ratio of 1:1 and 1:2 (female: male) respectively. Various physio-chemical parameters, viz, total ammonia nitrogen (TAN), nitrite, nitrate, pH, alkalinity, temperature, free carbon dioxide (CO 2) and dissolved oxygen (DO) of both tank water were analyzed to assess the performance of recirculating aquaculture system in maintaining the water quality. Gonadal development of the fishes was assessed and the spawning performance was recorded and finally, economic performance of the system was also evaluated. During the entire experimental period, mean monthly total ammonia nitrogen was less than 0.07 and 0.06 mg L−1 and mean monthly nitrite was less than 0.02 and 0.01 mg L−1 in orange spotted grouper and Indian pompano RAS tanks respectively. The pH (7.8–8.2), DO (>4 mg/L) and alkalinity (100–120 mg/L) were found to be in optimum range in both recirculating aquaculture systems. Carbon dioxide was found to be nil during the entire experimental period in both the systems. In fact these levels were comparable or less than that is reported as the permissible limits for broodstock development. Indian pompano and Orange spotted grouper matured and spawning was obtained with production of fertilized eggs round the year. Economic evaluation showed the price of 10,000 fertilized eggs of orange spotted grouper to be US $ 1.33. The design of RAS devised in the present study is efficient in controlling and maintaining optimum water quality for broodstock development of both demersal and pelagic finfishes. The fishes stocked in RAS attained final maturation and round the year spawning was obtained. [ABSTRACT FROM AUTHOR]

• Slow sand after rapid sand filters (RSF-SSF) produced best seawater for fish tanks. • RSF-SSF lowered microbial growth potential in filtrate by 1 order of magnitude. • Turbidity remained low in tanks fed with RSF-SSF for dusky grouper cultivation. • Biofilm growth on walls was smaller in tanks operated with RSF-SSF treated water. A rapid sand filter (RSF, 12 m3 m−2 h−1) and a rapid sand filter followed by slow sand filter (RSF-SSF, 0.1 m3 m−2 h−1) were compared to investigate whether the biological activity in the RSF-SSF would improve turbidity reduction and control of biofilm growth in seawater aquaculture of juvenile dusky grouper over a 31 days test period. The RSF-SSF combination produced water with lower turbidity than RSF, turbidity breakthroughs in RSF were effectively abated by SSF. Microbial growth potential (MGP) measured by a growth assay with Pseudoalteromonas spongiae in samples filtered through 0,2μm membranes was significantly smaller in SSF filtrate (MGP, 3.2 ± 0,1 logCFU) than in RSF filtrate (3.9 ± 0,6 logCFU). Turbidity in fish tanks fed with RSF-SSF and RSF effluent remained below 1 NTU and 6 NTU, respectively, inspite of the large amount of food not consumed by the fish and of the tanks remaining open to the atmosphere. Surface biofouling on PVC samples was assessed by protein and carbohydrate analysis. It was less pronounced on bottoms of tanks operated with RSF-SSF treated water but similar on tank walls for both types of water. Carbohydrates were present in much larger quantities than proteins in bottom biofilms, but the opposite occurred in wall biofilms. Diatoms were dominant in RSF but not in RSF-SSF tank biofilms. Dusky grouper survival and growth was similar for the two types of water. The benefit of reduction of microbial growth potential achieved in SSF pretreatment was successfully captured in lesser tank surfaces biofilm colonization and by lower water turbidity in the tanks. [ABSTRACT FROM AUTHOR]

Abstract In the present article, ASPEN Plus is used to develop a process model of the hydrogen-rich gas production through cleaning and catalytic conditioning of producer gas. The process includes producer gas cleaning using venturi scrubber and sand bed filter followed by compression of the gas to 0.6 MPa using compressor. The clean producer gas along with steam undergoes high temperature water gas shift reaction to produce hydrogen-rich gas. The power law kinetic model for commercial HTS catalysts reported in the literature is used in the model. Experimental results from our previous study and those reported in the literature are used to validate the developed model for the compositions of CO & H2 in the product gas. The validated model is further simulated to study the effects of parameters such as reactor temperature, catalyst bed length and steam to CO ratio on the product gas composition. The optimum operating conditions for maximizing CO conversion are found and reported. The maximum H2 composition and CO conversion predicted by the model are 27.029% 97.5479% respectively and the corresponding operating conditions are reactor; temperature of 350 °C, S/CO of 8 and GHSV 1000 h−1. Highlights • A macroscopic steady state process simulation is carried out using Aspen plus. • Model includes cleaning, compression and WGS catalytic treatment of producer gas. • Model is validated with the CO and H 2 composition in product gas for different GHSV. • The optimal values are reactor temperature of 350 ̊C, S/CO 8, and GHSV of 1000 h−1. [ABSTRACT FROM AUTHOR]

Three nitrate degrading bacteria, namely S1, S2 and S3 strains, were isolated from soil samples collected from agricultural sites at Polonnaruwa, Oruwala and Gampaha, Sri Lanka respectively. Among the isolated strains, S1 showed a maximum nitrate removal rate of 4.20±0.08 mg/L/day whereas S2 and S3 showed nitrate removal rates of 3.45±0.57 mg/L/day and 3.72±0.19 mg/L/day, respectively. The nitrate removal abilities of all three strains were measured at different temperatures (25oC, 30oC, 32oC), different pH (7.0, 7.5, 8.0) and for different nitrate concentrations (15, 30, 45 mg/L) in vitro. The maximum nitrate degrading rate by the bacterium S1 (4.52±0.01 mg/L/day), S2 (4.25±0.47 mg/L/day) and S3 (4.04±0.09 mg/L/day) were detected at 32°C whereas the highest degradation rate for S1 (4.6±0.05 mg/L/day), S2 (4.38±0.03 mg/L/day) and S3 (4.14±0.25 mg/L/day) bacteria strains was reported when the pH was 8.0. The maximum nitrate degradation was found to be 5.88±0.17, 5.67±0.45 and 5.71±0.43 mg/L/day for S1, S2 and S3 bacteria strains when 45 mg/L of nitrate was present in the medium. A biochemical test tentatively identified the isolates S1, S2 and S3 as Pseudomonas sp., Bacillus sp. and Proteus sp. The bio sand filter developed in cooperating all three bacterial strains showed 6.12±0.06 mg/L/day of nitrate degradation rate within 24 hours. [ABSTRACT FROM AUTHOR]

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Copyright of Acta Scientiarum Polonorum. Formatio Circumiectus is the property of Wydawnictwo Uniwersytetu Rolniczego im. Hugona Kollataja w Krakowie and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract In this study, a new hybrid system using multi-layer slow sand filter (MSSF), micro filter (MF) and ultra filter (UF) was investigated for the chemical oxygen demand (COD), linear alkylbenzene sulfonate (LAS), total suspended solid (TSS) and turbidity removal from the greywater at different organic loading rates (OLRs) (3.15–19.28 gCOD/(L.d) in a laboratory scale over a period of 157 days. The best removal efficiencies for COD, LAS, TSS, and turbidity were 98.22, 99.97, 99.99, and 99.98 percent, respectively using the MSSF-MF-UF hybrid system. The best removal efficiencies of LAS were 86.7, 89.6, and 98.37 percent, respectively in the OLR of 3.15 gCOD/(L.d). The scanning electron microscopy (SEM) images confirmed that biofilm grew appropriately in the media using the MSSF. Moreover, the increase of OLRs in the hybrid system decreased the removal efficiency levels of COD, LAS, TSS, and turbidity. However, the average effluents of LAS, TSS, and turbidity in the hybrid system were 0.04 mg/L, 1.55 mg/L, and 1.04 NTU, respectively for all OLRs, which were lower than the standard measures for reuse of water. In fact, the combination of biological process (MSSF) with membrane process (MF and UF) led to a more effective LAS and suspended solids (SS) removal in the grey water. Therefore, the combination of MSSF-MF-UF can be applied for removal of LAS and SS. Highlights • a new hybrid system was investigated for pollutant removal from greywater. • With increasing the Organic Loading Rates, hybrid system efficiency was decreased. • The effluents quality were met the standards for water reuse. • Combination of biological - membrane process led to significant pollutant removal. [ABSTRACT FROM AUTHOR]

Sand filtration is a primary stage of treatment for reuse of greywater. This study aimed at assessing the volatile solid removal efficiency of a sand filter and imitating its performance using analytical simulation. This study used artificial greywater, medium sand as a filtering material, and nine PVC cylinders as filter columns. Samples of the sand were collected after 6, 14 and 21 days, with the aim of specific deposit determination. The vertical distribution of specific deposit (volatile solids) in the sand filters was typical for gravitationally operated sand filters. Relatively high removal efficiency of volatile solids (51–60%) was achieved at relatively low cumulative hydraulic load. The average removal efficiency of organic compounds (detected as chemical oxygen demand) was 26.8%. Maximum specific deposit was achieved for a cumulative hydraulic load of 363.6 m. The filter coefficient was identified empirically for application of the Iwasaki formula. The filter coefficient λ was corrected for a better fit of the modelled values with measured values. [ABSTRACT FROM AUTHOR]

Abstract The critical situation of domestic wastewater treatment in the rural areas of Brazil stimulates the development or improvement of on-site systems using cheap and sustainable materials that can be applied in small and isolated communities. Although this is an important theme, few real scale systems have been studied. This study investigated a full-scale on-site domestic wastewater treatment system composed of a septic tank, an anaerobic filter filled with green coconut husks (Cocos nucifera) and an intermittent sand filter. The experiment was conducted in a rural area located in the city of Campinas (Brazil) and the system was built to serve a small community. The quality of the effluent generated by this combination is in accordance with Brazilian and European legislation and even allows for its reuse in agricultural activities. The results also demonstrate the feasibility of using coconut husks in anaerobic filters, providing a new and more sustainable destination for this material, which is normally treated as solid waste. The combination was shown to be a viable technology for small communities. [ABSTRACT FROM AUTHOR]

Abstract In order to control bacterial pollution in water treatment, it is necessary to prepare efficient antibacterial materials. Novel chitosan chloride-graphene oxide (CSCl@GO) composites were prepared via a one-step solution blending method. The composites were characterized by FT-IR, XRD and TEM techniques. The antibacterial mechanism of CSCl@GO composites was investigated using gram-negative bacteria E. coli and gram-positive bacteria S. aureus as two model microorganisms. The antibacterial properties of CSCl@GO composites for complex bacteria in the cooling water system were researched. In addition, the CSCl@GO composites modified quartz sand filter media (CSCl@GO/QS) were synthesized. The antibacterial performance of CSCl@GO/QS filter media in secondary effluent of domestic sewage was also investigated. The results showed that E. coli and S. aureus were completely inactivated after treatment with 100 mg·L−1 of CSCl@GO composites for 15 min. When adding CSCl@GO composites to E. coli or S. aureus suspension, the protein leakage was 12.7 or 9.9 times higher than that in the blank experiment after 12 h. The antibacterial rate of CSCl@GO composites in circulating cooling water reached 95.74% when the mass fraction of GO was 0.6%. After the CSCl@GO/QS filter media were backwashed for 3 times, the antibacterial rate could still be above 90%. Graphical abstract Unlabelled Image Highlights • CSCl@GO composites and CSCl@GO/QS filter media with excellent antibacterial activity were synthesized. • The antibacterial mechanism of CSCl@GO composites was investigated using pure bacteria. • The antibacterial applications of CSCl@GO composites and CSCl@GO/QS filter media for complex bacteria were researched. • After the CSCl@GO/QS filter media were repeatedly used for 3 times, the antibacterial rate was still up to 90%. [ABSTRACT FROM AUTHOR]

Abstract In the top layer of aerated rapid sand filtration systems, uncharged As(III) is biologically converted to charged As(V). Subsequently, the main removal mechanism for As(V) is adsorption onto oxidised, flocculated Fe(III) (hydrous ferric hydroxides; HFO). The aim of this research was to understand the interactions between As and Fe in biologically active rapid filter columns and investigate the effect of different operational modes on Fe removal to subsequently promote As removal. For this purpose, different filter media column experiments were performed using natural, aerated groundwater containing 3.4 μg/l As(III). Results show that independent of the filter media size, complete (biological) conversion of As(III), manganese, ammonium and nitrite was achieved in approximately 70 days. After ripening, enhanced As removal was achieved with a top layer of coarse media or by dosing additional Fe(III). Addition of Fe(II) did not have the same effect on As removal, potentially due to heterogeneous Fe(II) oxidation in the upper layer of the filter, attaching rapidly to the filter grain surface and thereby preventing HFO flocs to penetrate deeper into the bed. Increasing the flow rate from 1 to 4 m/h did not improve As removal and lowering the pH from 8 to 7.4, resulted in an 55% increased removal of dissolved As. Altogether it is concluded that As removal in biologically active rapid sand filters can be improved by applying coarser filter media on top, in combination with dosing Fe(III) and/or pH correction. Graphical abstract Image 1 Highlights • Coarse filter media enhanced As adsorption onto hydrous ferric oxides during rapid filtration. • Fe(III) addition prior to sand filtration resulted in more As removal compared to Fe(II) addition. • Lowering the pH in the range of 7.4–8.0 resulted in a positive effect on As removal. • Increasing filtration velocity from 1 to 4 m/h decreased As adsorption. [ABSTRACT FROM AUTHOR]

Abstract The removal and fate of contaminants of emerging concern (CECs) in water treatment systems is of interest given the widespread occurrence of CECs in water supplies and increase in direct potable reuse of wastewater. In this study, CEC removal was investigated in pilot-scale biologically-active granular activated carbon (GAC)-sand and anthracite-sand filters under different hydraulic loading rates and influent CEC concentrations over a 15-month period. Eight of the most commonly detected compounds in a survey of CEC occurrence in drinking water were selected for this study: atenolol, atrazine, carbamazepine, fluoxetine, gemfibrozil, metolachlor, sulfamethoxazole and tris(2-chloroethyl) phosphate (TCEP). GAC-sand biofilters provided superior CEC removal for all compounds (mean removal efficiencies: 49.1–94.4%) compared to anthracite-sand biofilters (mean removal efficiencies: 0–66.1%) due to a combination of adsorption and biodegradation. Adsorption was determined to be the dominant removal mechanism for most selected CECs, except fluoxetine, which had the greatest biodegradation rate constant (0.93 ± 0.15 min−1 at 20–28 °C). The mean removal efficiency decreased by 16.5% when the loading rate increased from 2 to 4 gpm/ft2 (4.88–9.76 m/h). A significant reduction in CEC removal was observed after 100,000 bed volumes when the influent CEC concentration was low (100–200 ng/L), whereas no significant reduction was observed during spike dosing (1000–3000 ng/L). A regression analysis suggested that biodegradation rate, hydraulic loading rate, influent CEC concentration, throughput, influent dissolved organic carbon (DOC) concentration, and CEC charge are important parameters for predicting CEC removal performance in GAC-sand biofilters. Graphical abstract Image 1 Highlights • GAC-sand biofilters provided greater CECs removal than anthracite-sand biofilters. • Adsorption is the dominant removal mechanism for CECs in GAC-sand biofilters. • Higher CECs removal was achieved with lower loading rate and/or lower throughput. • An empirical relationship for CECs removal in GAC-sand biofilters was developed. [ABSTRACT FROM AUTHOR]

Abstract Effective removal of natural organic matter (NOM) during water treatment is crucial as disinfection by-products (DBPs) such as trihalomethanes in the final drinking water are formed when residual NOM reacts with the disinfectant such as chlorine. This study compared the NOM removal efficiency by granular activated carbon (GAC) filtration, an ultrafiltration membrane and conventional water treatment plant. The NOM removal efficiency by GAC and submerged ultrafiltration process was conducted at pilot scale level and the conventional water treatment process assessment using a full scale water treatment plant. The performance of the three process train in removing NOM was conducted in parallel. On average, the conventional water treatment processes (coagulation, sedimentation and sand filtration) removed 61% and 24% NOM as indicated by UV 254 and dissolved organic carbon (DOC) removal, respectively. A respective reduction of 73% and 25% of UV 254 and DOC was achieved by ultrafiltration. The GAC filter column (preceded by a sand filter column) achieved UV 254 removal of 86% and DOC removal of 28%. Conventional water treatment removed the hydrophobic high molecular weight (HMW) NOM fraction while GAC and ultrafiltration not only increased removal of HMW NOM, but substantially increased removal of the intermediate (IMW) and low molecular weight (LMW) NOM. Addition of GAC filtration to the conventional treatment process appeared superior to ultrafiltration and conventional treatment and increased the overall NOM removal efficiency. [ABSTRACT FROM AUTHOR]

Design and operation of tertiary wastewater filters are not always well understood because of the inherent complexities of the wastewater matrix. Here, comparison of single, dual, triple and quadruple media (anthracite, flint, alumina and magnetite) filters were made to understand how the depth, media type and solids concentration influenced performance. The filter was improved by making the media deeper; however, the top 0.1 m of the filter retained the most solids. Additional layers of filter materials from single, dual, triple to quadruple improved the filter performance for the same depth of filter bed. [ABSTRACT FROM AUTHOR]

Biomass converting processes often struggle with downstream processing of dilute multicomponent mixtures. Liquid-liquid extraction is perfectly suited for removing carboxylic acids from aqueous streams, but solvent recovery is still energy intensive. Solvent recovery is simplified by reactive distillation, whereas the carboxylic acids are directly converted into their corresponding methyl esters. A process concept on the basis of formic acid and acetic acid isolation was evaluated and discussed for uncatalyzed and catalyzed batch reactive distillation with the acid laden solvent Cyanex® 923. 4-Dodecylbenzenesulfonic acid was used as catalyst. Catalytic conversion yielded 100% methyl formate and 88% methyl acetate formation. [ABSTRACT FROM AUTHOR]

Biofilters have been shown to be efficient for removing pollutants from different water effluents, but little information is available about their capacity to remove highly polar pesticides from agricultural run-off waters. In this study, we assess the capacity of three different biofilter-supporting materials (sand, peat soil, and pine bark) to remove five phenoxyacid herbicides (mecoprop, dicamba, MCPA, dichlorprop and 2,4-D) and five non-ionic pesticides (atrazine, simazine, fenitrotion, diazinon, and alachlor) from real agricultural run-off waters. The experimental design included three columns 120 cm in length and 15 cm in diameter, each filled with 100 cm of one of the selected supporting materials. After 30 days of acclimation, the columns were fed with agricultural run-off water spiked at 10 μg L−1 with each of the studied pesticides for 20 days at a hydraulic loading rate (HLR) of 0.32 m day−1. The results show that the sand filter was the best supporting material for removing phenoxyacid herbicides (77% on average), whereas peat soil and pine bark were best for removing non-ionic pesticides (72% on average). The attenuation of mecoprop and dichlorprop correlated negatively with the enantiomeric fraction. Therefore, this study shows that the use of waste-to-product materials in biofilter systems is a good solution for removing pollutants from agricultural run-off waters. [ABSTRACT FROM AUTHOR]

A laboratory-scale slow sand filtration (SSF) system was used to investigate biomass formation in different depths of SSF depending on various operating conditions in regard to filtration rate and influent iron-manganese concentrations. Results suggest that biomass formation occurs mainly in the uppermost 1.5 cm of the filter bed with slight contributions from layers between 1.5 cm and 14.5 cm. The highest volatile solids (VS) accumulation was observed in the uppermost layer as 16.93±0.07 mgVS/g dry sand, and the accumulation was found to be a function of both filtration rate and influent iron-manganese concentrations. Hydraulic conductivities were tested as a measure of biomass formation. The highest initial value of hydraulic conductivity was measured as 13.7 μm/s, while the lowest values ranged from 3.28 to 6.62 μm/s at the end of 55 days of operation. Hydraulic conductivities of the upper layers decreased quickly with time, while slight reductions were observed in hydraulic conductivities of the lower layers. [ABSTRACT FROM AUTHOR]

Sludge conditioning is an important stage in sludge management. In the present study, a sequence of freeze/thaw-electro-Fenton process was designed and specific resistance filtration (SRF) was monitored during sludge conditioning as an important factor in sludge dewaterability. Furthermore, protein and polysaccharide concentrations were measured during the experiments. Results showed that the lowest SRF value contributed to -10°C in freezing process which showed a reducing trend by decreasing solution pH. In addition, results revealed that solution pH less than 3 caused a significant improvement in sludge dewatering; so the lowest SRF has been registered at pH = 2. By increasing current intensity from 0.5 to 1A, SRF values were reduced and then followed by an enhancement with increasing current intensity to 3.2 A. The lowest SRF value (6.1 × 104 m/kg) was obtained at H²O² = 30 mg/L which was the best conditions for sludge dewatering. [ABSTRACT FROM AUTHOR]

The aim of this study is to examine the application of a low cost ceramic filter for the treatment of sand filter backwash water (SFBW). The treatment process is comprised of pre-coagulation of SFBW with aluminum sulfate (Alum) followed by continuous filtration usinga low cost ceramic filter at different trans-membrane pressures (TMPs). Jar test results showed that 20 mg/L of alum is the optimum dose for maximum removal of turbidity, Fe, and Mn from SFBW. The filter can be operated at a TMP between 0.6 and 3 kPa as well as a corresponding flux of 480-2000 L/m²/d without any flux declination. Significant removal, up to 99%, was observed forturbidity, iron (Fe), and manganese (Mn). The flux started to decline at 4.5 kPa TMP (corresponding flux 3280 L/m²/d), thus indicated fouling of the filter. The complete pore blocking model was found as the most appropriate model to explain the insight mechanism of flux decline. The optimum operating pressure and the permeate flux were found to be 3 kPa and 2000 L/m²/d, respectively. Treated SFBW by a low cost ceramic filter was found to be suitable to recycle back to the water treatment plant. The ceramic filtration process would be a low cost and efficient option to recycle the SFBW. [ABSTRACT FROM AUTHOR]

Green roofs are used increasingly to alleviate peaks of water discharge into the sewage systems in urban areas. Surface runoff from roofs contain pollutants from dry and wet deposition, and green roofs offer a possibility to reduce the amounts of pollutants in the water discharged from roofs by degradation and filtering. These pollutants would otherwise enter wastewater treatments plants and ultimately end up in sewage sludge that is spread on agricultural soils. The most common substrates used in green roofs have limited capacity for filtration and sorption. Also, more sustainable alternatives are sought, due to the high carbon footprint of these materials. Biochar is a carbon-rich material produced by pyrolysis of biomass, and several types of biochar have been described as good sorbents and filter materials. Biochar is also a light and carbon negative material, which may fulfill other desired criteria for new green roof substrates. We here report on an experiment where two types of biochar, produced from olive husks at 450 °C or from forest waste at 850 ° C were mixed with volcanic rock or peat, and tested for retention capacity of phenanthrene and six heavy metals in a column experiment with unsaturated gravimetric water flow lasting for 3 weeks. The results suggest that biochar as a component in green roof substrates perform better than traditional materials, concerning retention of the tested pollutants, and that different types of biochar have different properties in this respect. [ABSTRACT FROM AUTHOR]

Using experimental data obtained from in vitro bioaugmentation studies of a sand filter community of 13 bacterial species, we develop an individual-based model representing the in silico counterpart of this synthetic microbial community. We assess the inter-species interactions, first by identifying strain identity effects in the data then by synthesizing these effects into a competition structure for our model. Pairwise competition outcomes are determined based on interaction effects in terms of functionality. We also consider non-deterministic competition, where winning probabilities are assigned based on the relative intrinsic competitiveness of each strain. Our model is able to reproduce the key qualitative dynamics observed in in vitro experiments with similar synthetic sand filter communities. Simulation outcomes can be explained based on the underlying competition structures and the resulting spatial dynamics. Our results highlight the importance of community diversity and in particular evenness in stabilizing the community dynamics, allowing us to study the establishment and development of these communities, and thereby illustrate the potential of the individual-based modelling approach for addressing microbial ecological theories related to synthetic communities. [ABSTRACT FROM AUTHOR]

The environmental presence of organic micro-pollutants (OMPs) has posed increasing risks on aquatic organism and human health. The performance of three commonly used advanced wastewater treatment trains, coagulation-sand filter, coagulation-biological aerated filter (BAF) and ozonation-biological activated carbon (BAC), in removing fifteen residual contaminants and bio-toxicity of the effluent from a local municipal wastewater treatment plant (WWTP) were investigated. Relatively high level of OMPs (0.69–14.71 μg/L), genotoxicity (22.64 μg 4-NQO/L) and estrogenic activity (1.4 μg E2/L) were observed from the secondary effluent (SE). Limited OMPs and bio-toxicity reduction was achieved during coagulation with 20 mg/L of polymeric aluminium and sand filter. Ozonation exhibited high advantage in OMPs, genotoxicity and estrogenic activity reduction. More than 80% of removal was achieved for most OMPs after ozonation with normalized dose of 1.25 mg O 3 /mg DOC, and the removal of OMPs was consistent well with the second reaction kinetics constants of OMPs with ozone. Based on Pearson correlation analysis, spectroscopy indicators such as UV 254 and total fluorescence (TF) exhibited a high positive correlation with genotoxicity reduction, while estrogenic activity was related well with OMPs variation. To sum up, spectroscopic indicators showed a high potential to indicate the OMPs and bio-toxicity of SE. [ABSTRACT FROM AUTHOR]

It was found that the operational temperature and the incorporation of microbial fuel cell (MFC) into anaerobic membrane bioreactor (AnMBR) have significant effect on AnMBRs’ filtration performance. This paper addresses two issues (i) effect of temperature on AnMBR; and (ii) effect of MFC on AnMBRs’ performance. The highest COD removal efficiency was observed in mesophilic condition (45 °C). It was observed that the bioreactors operated at 45 °C had the highest filtration resistance compared to others, albeit the excellent performance in removing the organic pollutant. Next, MFC was combined with AnMBR where the MFC acted as a pre-treatment unit prior to AnMBR and it was fed directly with palm oil mill effluent (POME). The supernatant from MFC was further treated by AnMBR. Noticeable improvement in filtration performance was observed in the combined system. Decrease in polysaccharide amount was observed in combined system which in turn suggested that the better filtration performance. [ABSTRACT FROM AUTHOR]

Domestic wastewater needs to be treated because it can pollute the environment, either water bodies, ground water, or soil. One alternative to treat domestic wastewater is using subsurface constructed wetland methods. This method has advantages, among others, like cheap, simple technology and can be applied to the area of ample land. In this research, subsurface constructed wetlands-multilayer filtration with vertical flow type using Melati Air (E.paleafolius) in field scale to treat domestic wastewater from canteens and gray water toilet of Senior High School at Bekasi with treatment capacity for 2261 L/day. Subsurface constructed wetlands-multilayer filtration with vertical flow type is an advanced treatment in this research. For preliminary treatment the collecting and aeration tank is used. Performance of subsurface constructed wetland-multilayer filtration with vertical flow type was able to achieve effluent COD parameters of 40 mg/L (standard 100 mg/L) from an average influent of 350 mg/L with removal efficiency of 90%, while BOD was successfully degraded to 33.00 mg/L (quality standard 30 mg/L) of an average influent concentration of 350 mg/L. In addition, the parameters analyzed are total nitrogen, the total phosphate succeeded to meet the quality standard. Based on the results of laboratory analysis, the reactor is able to treat organic loading of 500-700 kg BOD5/Ha/D compared to previous research which is range from 40-300 kg BOD/Ha/D. Similarly, the value of K in this study ranged from 0.35-0.57 m/day for BOD and 0.37-0.45 m/day for COD compared to precious research which is 0.055-0.16 m/day for BOD and 0.027-0.16 m/day for COD. [ABSTRACT FROM AUTHOR]

Membrane separation processes are attracting increasing interest for the treatment of industrial wastewaters owing to its high organic and inorganic content removal efficiency and material stability. Herein, we have presented an approach to modify polyethersulfone (PES) membrane using aluminosilicate particles (ASPs) for high permeability and separation performance against tannery and distillery wastewater. PES:ASPs ultrafiltration membrane was developed by phase inversion technique at different weight ratios of 0:100, 10:90, 20:80, 30:70, and 40:60 of PES:ASPs. The functional groups and hydrophilicity were analyzed by X-ray diffraction (XRD) and contact angle, respectively. The modified membranes displayed improved wastewater permeability and higher flux compared to the neat PES membrane. The moderate removal of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids, chlorides, and sulfates from tannery and distillery wastewaters were attained for all ASPs-based PES membranes. In the case of tannery effluent treatment, high BOD reduction of 92% was observed for 80:20 weight ratio of PES:ASPs membrane and 75% BOD reduction for the pure PES membrane. The sulfides removal was 2.21 mg L−1 for 90:10 weight ratio of PES:ASPs membrane when compared with the initial quantity of 42 mg L−1 distillery wastewater. The PES:ASPs membrane with 80:20 weight ratios presented the best COD and BOD removal performance. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1612-1620, 2017 [ABSTRACT FROM AUTHOR]

Bioleaching is a promising technology for removal of metals from sludge and improvement of its dewaterability. Most of the previous studies of bioleaching were focused on removal of metals; bioleaching in cold environments has not been studied extensively. In this study, Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans were acclimated at 15 °C and co-inoculated to explore the optimal conditions for improvement of sludge dewaterability and removal of metals by the sequencing batch reactors. The data show after 6 days of bioleaching at 15 °C, 89.6% of Zn, 72.8% of Cu and 39.4% of Pb were removed and the specific resistance to filtration (SRF) was reduced to ~12%. In addition, the best conditions for bioleaching are an initial pH of 6, a 15% (v/v) inoculum concentration, and A. thiooxidans and A. ferrooxidans mixed in a ratio of 4:1. We found that bioleaching of heavy metals is closely related to final pH, while the sludge SRF is dominated by other factors. Bioleaching can be completed in 6 days, and the sludge dewaterability and removal of metals at 15 °C meet the requirements of most sewage treatment plants. [ABSTRACT FROM AUTHOR]

Nitrogen discharge from decentralized and onsite wastewater treatment systems, such as recirculating sand filters, stabilization ponds, and septic tanks, is an important source of groundwater and surface water contamination. This study demonstrated a simple baffled bioreactor (BBR) technology, operated with an intermittent aeration mode, that effectively removed nearly all nitrogen for small flow wastewater treatment. The BBR is characterized by an aeration zone, followed by an integrated internal settler, which automatically retains a high biomass concentration of approximately 6 g/L without using a separate sludge return device. Long-term testing results indicated that this process had reduced the chemical oxygen demand and total nitrogen concentration to approximately 20 mg/L and less than 3 mg-N/L, respectively, under an operational temperature of 7.1 °C to 24.7 °C. The average effluent ammonia and nitrate concentrations were 0.75 and 0.61 mg-N/L, respectively, indicating that both nitrification and denitrification had been completed. In addition to nitrogen removal, this BBR had removed approximately 65% of the total phosphorus. [ABSTRACT FROM AUTHOR]

Based on a successful experimental result from laboratory and bench scale for treatment of wastewater from beverages industry, an industrial and efficient treatment unit is designed and constructed. The broad goal of this study was to design and construct effluent, cost effective and high quality treatment unit. The used technology is the activated sludge process of extended aeration type followed by rapid sand filters and chlorination as tertiary treatment. Experimental results have been considered as the basis for full scale design of the industrial capacity of 1600 m 3 /day treatment plant. Final effluent characteristics after treatment comply with Egyptian legalizations after reducing COD and BOD 5 by about 97% and 95% respectively. So it is recommended to reuse treated effluent in textile industry in dyeing process. [ABSTRACT FROM AUTHOR]

Bio-sand filters (BSFs) are point-of-use (POU) potable water filtration systems commonly used in low-income communities at household level. The principle of operation is similar to that of a slow sand filter and the major difference is that they are operated intermittently at the POU. It is one of the emerging low-cost technologies which makes use of readily and locally available construction materials but is poor in the removal of nitrates. In order to enhance the removal of nitrates through denitrification, a modified BSF with ethanol as an external carbon source at C =N ratios of 1.1 and 1.8 was investigated. In the absence of an external carbon source, the nitrate removal efficiency was 32 %, whilst removal efficiencies at C=N ratios of 1.1 and 1.8 were 44 and 53% respectively. The inflow rate reduced significantly from an initial flow rate of 0.04 to 0.01m3 h-1. The reduction in the inflow rate was mainly due to the growth of the biological layer on the filter media. The study showed that the use of an external carbon source like ethanol in bio-sand filtration enhances the removal of nitrates in potable water. [ABSTRACT FROM AUTHOR]