Pond Effluent Research Articles

Resource recovery for environmental management of dilute livestock manure using a solid-liquid separation approach

Mechanical solid-liquid separation is an emerging closed-loop technology to recover and recycle carbon, nutrients and water from dilute livestock manure. This closed-loop concept is tested using a modular separation technology (Z-Filter) applied at full-scale for the first time to treat effluent from a pasture-based dairy. Effluent flow rates were 200–400 L min−1 at a total solids (TS) content of 0.52% (pH 7.2). Separation efficiency and composition of the separated solid fraction were determined, and chemically-assisted separation with cationic polymer flocculant with/without hydrated lime was also tested. Without flocculant and lime, 25.9% of TS and 33.4% of volatile solids (VS) ended up in the solid fraction, but total Kjeldahl nitrogen (TKN), phosphorus (P) and potassium recovery was not significant, likely being in poorly separable fine particle or soluble fractions. With a 5% flow-based dosage of flocculant, most of the TS (69%) and VS (85%), and notable amounts of TKN (52–56%) and P (40%) ended up in the solid fraction. Phosphorus recovery was further increased to 91% when both flocculant and hydrated lime was added up to pH 9.2. The solid fraction was stackable with 16–20% TS, making transport more economical to enable further processing and beneficial reuse of nutrients and organic matter. Removal of VS also reduces fugitive methane emissions from uncovered anaerobic effluent ponds. Overall, the results indicated that solid-liquid separation could provide improved environmental management options for dairy farmers with dilute manure effluent to beneficially utilise organic matter and nutrients.

Bioaccumulation of Heavy Metals Pollutants in Pichavaram Mangrove Ecosystem, Southeast Coast of India

Studies on contaminant bioaccumulation in tropical mangrove ecosystems are very limited. An attempt has been made to assess sources of primary productivity and chemical bioaccumulation behavior in true and associated mangrove plants, water, and sediments from the Pichavaram Mangrove Ecosystem. The water, sediment, and plant materials were collected at 7 different locations and the samples were analyzed to determine the concentration of heavy metals using a flame atomic absorption spectrophotometer. The result reviles that the maximum lead concentrations of 5.48 ppm/g were accumulated in sediment samples collected from shrimp pond effluent and 4.26 ppm/l from water during post-monsoon. The maximum Zinc concentration of 12.34 ppm/g was observed in sediment samples collected from degraded mangrove forests during post-monsoon and 10.99 ppm/g was observed in sediment samples during the summer season. Higher heavy metals concentration was observed during spring and summer this may be due to increased biological activities, land runoff and rainfall during these seasons. The maximum Copper concentration 9.07 ppm/g was observed in sediment at degraded mangrove forest during post-monsoon and 8.16 ppm/g was observed in sediment during the summer season. Heavy metals concentrations in different parts of A. marina mangrove plants were analyzed. In leaf sample, Pb 5.44 ppm/g in shrimp pond effluent site, Cd 4.97 ppm/g in degraded site, Zn 4.43 ppm/g in degrading site, Cr 2.17 ppm/g in Freshwater zone at Vellar, Hg 1.68 ppm/g in shrimp pond effluent site, Cu 0.86 ppm/g in Freshwater zone at Upannar was recorded. In stem sample Pb 6.89 ppm/g and Zn 5.67 ppm/g in the degraded site, Cd 5.27 ppm/g in the natural site, Hg 4.91 ppm/g in degrading, Cr 2.49 ppm/g and Cu 0.87 ppm/g in Freshwater zone at Upannar was recorded. In Avicennia roots, Cr 10.89 ppm/g in shrimp pond effluent, Pb 10.17 ppm/g in natural site, Cd 6.89 ppm/g in freshwater zone at Vellar, Zn 6.86 ppm/g in degrading mangrove site, Hg 5.48 ppm/g in degraded site, Cu 0.92 ppm/g in backwater mouth was recorded. Heavy metals contamination was observed in almost all the samples in higher concentrations. The results indicate that Avicennia marina have a greater potential to observe and accumulate higher concentration than associated mangroves. A. marina plant can be used for phytoremediation to remove the heavy metals from the mangrove ecosystem and will help for ecological studies, conservation and sustainable management of the mangrove habitats.

Impact of Fish Ponds on Stream Hydrology and Temperature Regime in the Context of Freshwater Pearl Mussel Conservation

Conservation of endangered, cold-stenothermic species, such as the freshwater pearl mussel (FPM) and its salmonid host fish, are particularly challenging in headwater streams as their last refuge areas. Understanding the impact of anthropogenic catchment features such as fish ponds on the hydrology and the temperature regime of such streams is, therefore, important. In this study, runoff in a FPM catchment with more than 150 small ponds was simulated using SWAT and compared to a scenario without ponds. Additionally, water temperature was monitored hourly along three steams over 2.5 years, at sites upstream and downstream of the inflow of pond outlet channels. Temperature metrics were related to land use within a 180 m corridor along the streams. Peak flows were reduced by 1.5% with ponds, while low flows were increased by 4.5%. In summer, temperature in pond effluents was higher than in the receiving stream, depending on the proximity of the inflow points. Discharge from close-by ponds increased summer stream temperature directly downstream of the inflow by up to 5.5 °C. These increased temperatures were partly compensated by groundwater contribution in forested areas. In contrast, stream temperature significantly further increased along stretches flowing through open land, persisting independently of pond inflows. We suggest incorporating this knowledge on pond- and land use-dependent effects on stream temperature regimes into the conservation management of FPM and other cold-stenothermic species, as well as into climate change mitigation strategies targeting an increased resilience against temperature extremes.

MLVSS / MLSS ratio’s standard value obtained from different aeration tank samples of different capacity sewage treatment plant - A case study

Waste water treatment system plays a vital role in controlling pollution of natural water bodies like lake, pond, river etc., by Municipal and Industrial effluents. Different industrial effluents play its own role in contaminating the water bodies which in turn creates huge impact for aquatic and terrestrial life. From past studies we understood that, all the sewage treatment systems have a secondary treatment step which are mainly driven by Bacterial oxidation or in other terms can be pronounced as Biological augmentation, Biological calcification etc., In environmental engineering term this bacterial growth will be pronounced as MLSS (Mixed Liquor Suspended Solids) and MLVSS (Mixed Liquor Volatile Suspended Solids). MLVSS will be an inclusive part of the MLSS and also can be sorted as live bacterial cells which can really does the oxidation process in the secondary treatment step of Sewage treatment plant. Hence, this study was performed to evaluate the percentage or concentration of MLVSS available in the total value of MLSS. For this study aeration tank water samples were collected from 6 different STP capacities from 6 different areas. All the samples were tested for MLSS and MLVSS concentration with the available standard method of drying. Drying with 105° C in oven gives the value of MLSS and drying with 550° C in furnace gives the value of MLVSS. With all the tested samples the concentration of MLVSS from the total MLSS was evaluated and standardized.

Effects of sausage industry effluents before and after bacterial biodegradation treatment and cytotoxicity in Allium

Water is essential in the food and meat processing industry. The processing industry is one of the major consumers of water, and consequently, generators of a significant amount wastewater effluents which pollute the water bodies heavily. The objective of this study was to evaluate the cytotoxic potential of raw effluent, anaerobic and aerobic ponds, and surface water of the Cleopatra stream pre- and post-discharge of the effluent from a sausage industry by Allium cepa L. test. At different sampling timepoints, tests on the roots were conducted, as follows: control samples of the self-bulb (0 h), treatment with effluent or water (24 h), and recovery in filtered water (24 h). The results showed that the raw effluent is cytotoxic, because it inhibited the cell division completely. However, this inhibition was not permanent as, after the recovery time, the cells divided again at a rate greater than that of the control. Wastewater from the anaerobic and aerobic ponds and before and after discharge into the stream was not found to be cytotoxic. At the time of recovery, an increase in cell division was observed in samples treated with wastewater from the anaerobic and aerobic ponds, which is possibly caused due to the presence of organic matter. Despite the efficiency of treatment methods, it is necessary to conduct studies that monitor the effluents from the industry and stream waters to ascertain possible impacts on the environment.

Bacteriological and Physicochemical Analysis of Fish Pond Effluents in Warri and Its Environs, Nigeria

Aims: This study was to ascertain the bacteriological and physicochemical characteristics of fish pond effluents.
 Study Design: Waste water samples were collected from six (6) different ponds, three (3) earthen ponds (A, B & C) and three (3) concrete ponds (D, E & F).
 Place and Duration of Study: The study was conducted in a laboratory in the Department of Environmental Management and toxicology, Federal University of Petroleum Resources, Effurun, Delta State, Nigeria. The research lasted for six months.
 Methodology: Standard procedures were adopted for sample collection, microbiological and physicochemical analyses. Waste water samples were analyzed for total bacterial count, total coliform count and Escherichia coli (E. coli) count. Physicochemical parameters measured were pH, electrical conductivity (EC), dissolved oxygen (DO) and temperature and many others.
 Results: Pond C which was an earthen pond was found with the highest bacterial, coliform and E. coli. counts (2.8 × 105 ±0.01, 1.2 × 103 ±0.10 and 0.5 ×102 ±0.04 cfu/ml), and pond F, a concrete pond, recorded the lowest bacterial and coliform counts of (2.3 × 104 ±0.05, 0.2 × 103 ±0.00 cfu/ml respectively and insignificant E. coli count. The isolated bacteria species were Lactobacillus sp., E. coli, Klebsiella sp., Staphylococcus sp., Streptococcus sp., Enterobacter sp. and Proteus sp. The occurrence of the isolated bacteria was highest in pond C with 71.43%. The values of turbidity and total hardness were above WHO and FEPA standards, while values of other physicochemical characteristics complied with WHO and FEPA standards. The antibiotics susceptibility test of the bacterial isolates revealed multiple antibiotics resistance.
 Conclusion: The study revealed that these ponds were disgustingly infected with pathogenic bacteria that could affect cultured fishes by causing diseases, lowering the fish yield and resulting into economic loss, threatening human’s health and contaminating the environment where the effluents are discharged into.

Treatment of waste stabilization pond effluent using natural zeolite for irrigation potential.

Direct utilization of treated effluent from natural treatment systems for irrigation can be challenging on sensitive plants due to high levels of salinity. Post-treatment of such an effluent prior to its applicability in irrigation can be of significant importance. In this study, the wastewater from a natural treatment plant was treated using a lab-scale filtration system with zeolite as a filter material. Three different column depths (0.5 m, 0.75 m, and 1 m) were used to investigate the effect of column depth on the treatment efficiency of the media. The suitability of the raw wastewater and the treated effluent from each column for irrigation purposes was investigated. The water quality parameters investigated were; electrical conductivity (EC), total dissolved solids (TDS), sodium (Na+), calcium (Ca2+), and magnesium (Mg2+). From the analysis results, it was observed that the column depth had a significant influence on the removal efficiency of the pollutants. The highest removal efficiency (94.58%) was achieved from the combination of electrical conductivity and 1 m column depth, while the lowest removal efficiency (10.05%) was observed from the combination of calcium and 0.5 m column depth. The raw wastewater fell mostly into a “very high” hazard, which is class four (C4) based on electrical conductivity and class four (S4) based sodium adsorption ratio; making it unsuitable for irrigation purposes. However, when the wastewater was subjected to 1 m column depth, the quality of the treated effluent improved significantly which in turn also improved the suitability of the effluent for irrigation purposes, with percent compliance ranging from 20.19% to 97.54%.

Application of palm oil mill waste to enhance biogas upgrading and hornwort cultivation

The potential of oil palm ash (OPA) to enhance H2S and CO2 removal from biogas by scrubbing with maturation pond effluent (MPE), and further the treatment of biogas scrubber effluent (BSE) by Ceratophyllum demersum L. (hornwort) cultivation were investigated in this study. The results show that OPA + MPE solution with pH 9.3 and alkalinity 7525 mg CaCO3/L was obtained with 0.7 kg/L OPA loading. A pilot scale scrubber was used to study the effects of absorbent flow rates of 60–210 L/h on upgrading to 300 L/h field biogas stream. At 210 L/h, the CO2 removal efficiencies were 33% and 53% for MPE and OPA + MPE, respectively. To approach 100% H2S removal efficiency, the minimum flow rates were 120 L/h for MPE and 90 L/h for OPA + MPE. 50–150 g wet weight of hornwort in 30 L diluted POME were loaded to investigate appropriate initial hornwort loading level for hornwort cultivation. The highest specific growth rate of 0.045 day−1 with biomass production of 3.8 g/day were obtained with a 50 g initial loading. Among the wastewaters (MPE, OPA + MPE, and BSE) treatment using hornwort cultivation, the highest 0.035 day−1 specific growth rate and 2.6 g/day biomass production of hornwort were obtained in diluted BSE cultivation, and in 3 weeks of cultivation. COD, nitrate, phosphate, and alkalinity decreased by 76%, 76%, 55%, and 5%, respectively. The Eco-Efficiency concept for palm oil mill waste utilization proposed in this study has a high potential for enhanced biogas upgrading by using OPA + MPE, and hornwort is a good candidate for BSE post-treatment integrated with biomass production.

Applicability of bio-synthesized nanoparticles in fungal secondary metabolites products and plant extracts for eliminating antibiotic-resistant bacteria risks in non-clinical environments

The abundance of antibiotic-resistant bacteria in the prawn pond effluents can substantially impact the natural environment. The settlement ponds, which are the most common treatment method for farms wastewater, might effectively reduce the suspended solids and organic matter. However, the method is insufficient for bacterial inactivation. The current paper seeks to highlight the environmental issue associated with the distribution of antibiotic resistant bacteria (ARB) from prawn farm wastewater and their impact on the microbial complex community in the surface water which receiving these wastes. The inactivation of antibiotic-resistant bacteria in prawn wastewater is strongly recommended because the presence of antibiotic-resistant bacteria in the environment causes water pollution and public health issues. The nanoparticles are more efficient for bacterial inactivation. They are widely accepted due to their high chemical and mechanical stability, broad spectrum of radiation absorption, high catalytic activity, and high antimicrobial activity. Many studies have examined the use of fungi or plants extract to synthesis zinc oxide nanoparticles (ZnO NPs). It is evident from recent papers in the literature that green synthesized ZnO NPs from microbes and plant extracts are non-toxic and effective. ZnO NPs inactivate the bacterial cells as a function for releasing reactive oxygen species (ROS) and zinc ions. The inactivation of antibiotic-resistant bacteria tends to be more than 90% which exhibit strong antimicrobial behavior against bacterial species.

Insights into ultrasound-promoted degradation of naphthenic acid compounds in oil sands process affected water. Part I: Accelerated H-abstraction and decarboxylation of aromatic and alicyclic compounds

Propelled by enormous increase in demand for fuel sources, Canadian oil sands are becoming increasingly important as a fuel source due to their abundance and upgrading capability. However, extraction of bitumen, a high acid crude (HAC) oil, requires 2–3 units of water per unit of oil resulting in naphthenic acid (NA)-rich oil sands process affected water (OSPW) collected in effluent ponds. This study illustrates the role of sonochemistry in the accelerated degradation through H-abstraction and subsequent decarboxylation of aromatic and alicyclic naphthenic acid model compounds. Benzoic acid and 3-methylcyclohexane carboxylic acid were selected as model NA compounds to investigate the mechanism of hydroxyl radical (OH•) initiated carboxylic acid degradation in 378 KHz sonochemical reactor. Established FTIR methods with low resolution LCMS spectroscopy confirmation were applied to determine the extent of carboxylic acid degradation and identify the formation of products. FTIR monitoring showed a non-linear degradation of carboxylic acids with formation of many intermediates highlighting the shift from cyclic carboxylic acids to cyclic alcohols during BA degradation. Subsequent decrease in carboxylic acid groups signifies scission of cyclic structures before complete mineralization. This is confirmed with the LCMS identification of products such as: 3-hydroxybenzoic acid and phenol. This study postulated new breakdown pathways for degradation of benzoic acid with complete mineralization at a sonochemical reaction time (SRT) of 4 h. A radical quenching process was also inferred through the formation of conglomerates during sonochemical degradation of BA. Extension of the study to 3-methylcyclohexane carboxylic acid (3mCHA) shows similar non-linearity with an increase in carboxylic acid groups indicating H-abstraction followed by ring-opened compounds. However, due to the complex nature of 3mCHA’s ring-opened compounds, complete mineralization is not achieved. The putative role of sonochemistry is a promising and sustainable degradation method for mitigating NAs in OSPW, but sonication periods need to be considered carefully to ensure adequate mineralization of their constituents and combinatorial methods with other advanced oxidation methods may be needed to enhance industrial application.In Part II, an in silico screening approach using first principles is reported to identify the breakdown of the organic compounds and determine molecular rates of reaction to confirm the mechanistic origins of the compounds formed.

Filter Efficiency with Red Rock as Post-Treatment of Stabilization Pond Effluent, Prototype Case Study San Marcos, Carazo, from April to September 2019

Filter Efficiency with Red Rock as Post-Treatment of Stabilization Pond Effluent, Prototype Case Study San Marcos, Carazo, from April to September 2019

Effects of shrimp pond effluent on functional traits and functional diversity of mangroves in Zhangjiang Estuary

In recent years, the scale of shrimp ponds has rapidly increased adjacent to mangrove forests. Discharge of shrimp pond effluent has led to degradation of the surrounding environment and reduction of biodiversity in the estuary. But it remains poorly understood how shrimp pond effluent affects functional traits and functional diversity of mangroves. We sampled roots, stems and leaves of Kandelia obovata and other mangrove plants, as well as sediments and pore water from shrimp pond effluent polluted area (P) and clean area (control area, C) in Zhangjiang Estuary in southeast coast of China. Twenty plant functional traits and six functional diversity indices were analyzed to explore the effects of shrimp pond effluent on individual plants and mangrove communities. The results showed that the discharge of shrimp pond effluent significantly affected the nutrient content in soils and pore water, for example, sediment NH4+ and NO3− concentration increased from 0.26 ± 0.06 to 0.77 ± 0.29 mg/g and from 0.05 ± 0.03 to 0.16 ± 0.05 mg/g, respectively, when comparing the C and P site. Furthermore, some mangrove plant functional traits such as plant height, diameter at breast height, canopy thickness and specific leaf area were significantly increased by the effluent discharge. Functional diversity in the polluted area reduced as a whole compared to the control area. In particular, ammonium and nitrate nitrogen input is the main reason to induce the changes of plant functional traits and functional diversity. Besides, the community structure changed from functional differentiation to functional convergence after shrimp pond effluent discharge. In addition, the long-term shrimp pond effluent discharge may lead to the ecological strategy shift of K. obovata, while different organs may adopt different ways of nutrient uptake and growth strategies in the face of effluent disturbance. In conclusion, pollution from shrimp pond does affect the functional traits of mangrove plants and functional diversity of mangrove community. These results provide strong evidence to assess the impact of effluent discharges on mangrove plants and provide theoretical basis for conservation and sustainable development of mangroves.

Preliminary Investigation of Microbial Community in Wastewater and Surface Waters in Sri Lanka and the Philippines

In this study, the composition and richness of bacterial communities in treated and untreated wastewater from hospitals, commercial, and non-commercial fish farming sites, sewage effluents, and surface waters, which included seawater and fresh water in Sri Lanka and the Philippines, were investigated through 16S rRNA gene amplicon sequence analysis. Firmicutes were found predominantly in Sri Lankan hospital wastewaters, while Cyanobacteria and Acidobacteria were typically detected in fish culture sites and the waste canal in Sri Lanka, respectively. The Shannon–Weaver index (SW) and number of Operational Taxonomic Units (OTUs) were higher in the Philippines than in Sri Lanka. The bacterial richness in the university non-commercial fish pond and sewage effluent displayed greater than that in hospital wastewaters. In addition, the bacterial richness was higher in the untreated wastewater compared to that in the treated wastewater in hospitals. These results indicate the differences among water types in terms of bacterial community, especially influenced by their source.

Are Rural and Small Community Aerated Wastewater Stabilization Ponds a Neglected Source of Microplastic Pollution?

Wastewater treatment systems collect and treat sewage that includes microplastics (MPs). However, we are not aware of any studies on the occurrence and distribution of MPs in wastewater stabilization ponds (WSPs), which serve small communities worldwide. Here, we characterized MPs (~45 µm–5 mm) in an aerated WSP serving ~500 houses and an adjacent lake. Putative MPs were most abundant in duckweed (Lemna minor) and sludge (75 ± 22 and 12.8 ± 3.1 particles/g, respectively: ±1 standard deviation (SD), n = 6, dry weight). In the water, average concentrations (particles/L ± 1 SD, n = 6) were highest in the pond (4.1 ± 0.6), followed by effluent (3.9 ± 0.5) and the lake (2.6 ± 0.6). Over 20 types of MPs were identified in each different compartment, with the distribution varying somewhat between the water, sludge, and duckweed. Polyester and polyethylene were the predominant types, followed by polyethylene terephthalate, polyacrylate, polyvinyl chloride, polystyrene, and others. Morphologies consisted of fibers (62–71%), fragments (28–37%), and beads (1–6%). High-density polymers were more frequently found in sludge. Potential sources of the MPs include synthetic textiles from laundry and other plastics washed down household drains. Overall, with ~786,000 MPs/day released in the pond effluent and with duckweed a source of food for waterfowl, we demonstrate that WSPs can be point sources of MPs to both aquatic and terrestrial ecosystems and thus deserve further scrutiny.

Contaminants and heavy metals along the mangrove area of Dongzhai Harbor, China: distribution and assessment

In recent decades, higher-place shrimp ponds are prevalent in coastal areas of developing countries. However, shrimp aquaculture has a growing negative impact on mangrove wetland ecosystems. Mangroves located in Dongzhai harbor are under threat continuously of this commercialization. Therefore, a comprehensive analysis of contaminants and heavy metals is necessary for Dongzhai harbor, considering the mangrove area was declined and ecological services offered to the coastal communities with an insight for future restoration activities. In this study, pond effluents (Total Nitrogen (TN), Ammonia Nitrogen (AN), Total phosphorus (TP), Chemical Oxygen Demond (COD)) and heavy metals (Cd, Cu, Pb, Zn) were monitored in Dongzhai harbor yearly between 2013 and 2017. The results showed that the contents of Cd, Cu, Pb, and Zn were far lower than the standards. However, the main contaminants were organic matter and nitrogen. Maximum values of COD and TN were 26.10 mg·L−1 and 1.34 mg·L−1, respectively in 2017. Single factor index, Nemerow's pollution index, and Trophic level index revealed that the heavily polluted areas were Tashi and Sanjiang town.

The Efficiency of Aquatic Macrophytes on the Nitrogen and Phosphorous Uptake from Pond Effluents in Different Seasons

The Efficiency of Aquatic Macrophytes on the Nitrogen and Phosphorous Uptake from Pond Effluents in Different Seasons

Improving the quality of stabilization pond effluents using hybrid constructed wetlands

Water shortage and excessive use of water resources in arid and semi-arid regions, such as Iran, highlights the importance of using treated wastewater, especially for the highly demanding agricultural sector. Constructed wetlands (CWs) are among green technologies that offer an efficient and cost-effective wastewater treatment. This study investigates the complementary treatment of effluent from the Fooladshahr wastewater treatment plant, Isfahan, Iran, using pilot-scale CWs with horizontal (H-CW) and horizontal-vertical flow (HV-CW). The performance of two substrates, pumice and gravel, and the effect of using plants (Phragmites australis) was compared. Maximum removal efficiencies of total suspended solids (TSS) and biochemical oxygen demand (BOD5) were observed in the case of unplanted and planted HV-CW with pumice bed, respectively. In the case of gravel bed, planted H-CWs demonstrated maximum chemical oxygen demand (COD) removal efficiency. The highest mean outflow concentrations for TSS, BOD5 and COD were obtained in unplanted H-CW with pumice bed, likely due to shorter retention times compared to HV-CWs, as well as due to the absence of plants providing the required physicochemical and biological conditions for high performance treatment. Phosphate (PO43−) removal efficiency demonstrated seasonal dependency, where the highest values were obtained in warm seasons. In the case of fecal coliforms (FC), no significant differences were observed between the studied HV-CWs during the whole study period. Based on our results, planted H-CW with gravel bed provided an optimum removal efficiency while requiring a smaller footprint and lower expenditure than HV-CWs. This study demonstrates the application of CWs as an affordable solution for treating domestic wastewater for various reuse application in developing countries with water crisis, such as Iran.

Fouling mitigation and enhanced dye rejection in UF and NF membranes via layer-by-layer (LBL) assembly and altering PVP percentage as pore former

In this study, ultrafiltration (UF) and nanofiltration (NF) membranes with different polyvinylpyrrolidone (PVP) percentages were firstly synthesized to explore membranes with the highest flux and flux recovery ratio (FRR). From the membranes fabricated, the UF membrane containing 1 and 2% PVP, and NF membrane containing 2% PVP were selected as the optimal membranes. In the following step, the selected membranes were modified using a layer-by-layer assembly with poly 4-styrenesulfonic acid-co-maleic acid (PSSMA) (negatively charged) and poly allylamine hydrochloride (PAH) (positively charged). The positively charged membranes were prepared by placing 3 bilayers of the polymers with an extra PAH positive layer [(PAH/PSSMA)3+PAH], while the negatively charged membranes were prepared with only 3 bilayers of the polymers [PAH-PSSMA]3. To investigate the effect of electrostatic attraction and repulsion and their effect on the removal of dye, two anionic (direct red 16) and cationic (methylene blue) dyes were used. Having relatively high flux close to the UF and high color removal efficiency almost similar to the NF was the main achievement of this study with the modified UF membrane (1 wt% PVP). The characterization of the selected membrane was elucidated in detail. The stability of the filtration process for the selected membrane (UF 1 wt%) was confirmed through removing algal color from a stabilization pond effluent (turbidity reduction from 58 to 1 NTU) in a cross-flow filtration setup.

Effects of Seasonal Variation on Performance of Conventional Wastewater Treatment System

The study was to determine the seasonal differences of conventional wastewater treatment process. This was done by sampling and analyses of wastewater samples from four different points during the dry and wet seasons of the year 2019. Water samples were taken from influent point, primary effluent, trickling filter effluent and final effluent. Gravimetric method was used in determining Total Suspended Solids (TSS) and Total Dissolved Solids (TDS). The BOD 5 technique was used for determination of Biological Oxygen Demand (BOD) and the digestion method was used for determination Chemical Oxygen Demand (COD). Temperature, pH and conductivity were measured using respective meters. Analysis of Variance showed that there was significant difference (p < 0.05) in all the parameters quantified at all the points of treatment during the two seasons. The results showed that BOD and COD both reduced from one point to the next during the two seasons of study. The TSS levels increased after primary pond effluent undergoing treatment at the trickling filter and the temperature also increased after the trickling filter effluent undergoing treatment at oxidation ponds. The levels of conductivity and TDS decreased from one treatment stage to the next during dry season but during the wet season the levels of these parameters increased from one stage to the next except that the levels reduced after the primary pond effluent underwent treatment at the trickling filter. The various stages of wastewater treatment plant under were effective during the two seasons however, wet season recorded lower figures for most of the parameters. Keywords: effluent, influent, wastewater, seasonal variation, ponds DOI: 10.7176/JEES/11-7-06 Publication date: July 31 st 2021

Potential and mechanism of glomalin-related soil protein on metal sequestration in mangrove wetlands affected by aquaculture effluents

Aquaculture effluent discharge containing heavy metals affects estuarine mangrove wetlands. Glomalin-related soil protein (GRSP) is recalcitrant organic matter that can be trapped in mangrove wetlands and is critical to metal sequestration. However, studies on the effects of long-term aquaculture effluents on metal pollution in adjacent mangrove wetlands and the ecological role of GRSP are lacking. For the first time, we revealed the effects of discharge histories (0, 8, and 14 years) of shrimp pond effluents on metals (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn), including the entire process from feed to metals binding with GRSP in mangrove soils. Results showed that mangrove soils receiving the effluents generally had higher or similar metal loadings compared to the control, and long-term effluent discharge increased the potential toxicity of the metals. Aquaculture feed could be a main source of metal input. Redundancy analysis indicated that 14-year effluent discharge increased the pH, bulk density, total nitrogen, and total phosphorus of mangrove soils, reducing the potential of GRSP-bound metals. Scanning electron microscopy and infrared spectroscopy characterisation revealed that effluent disturbances changed the surface morphology and functional group contents of GRSP. This study provides insights into using GRSP as an aquaculture pollution bioindicator.