Search

This study investigates the treatment of combined wastewater from Hattar Industrial Estate using Biofilm Wetlands (BW) planted with monoculture species: Eichhornia crassipes (EAC), Pistia stratiotes (WL), and Arundo donax (GR). Each species showed distinct capabilities in organic degradation, metal uptake, and pH stabilization. BW2, planted with EAC, achieved the highest total solids (TS) and total suspended solids (TSS) removal efficiencies of 66% and 65%, respectively. GR effectively reduced initial COD concentrations from 232 mg/L to 58.67 mg/L, while EAC and WL reached reductions to 72.78 mg/L and 70.67 mg/L, respectively. Overall, the plant efficiency ranking was EAC > GR > WL. These findings underscore the potential of these plant species in synergistic BW systems, highlighting their role as natural solutions for remediating complex industrial effluents. This research contributes to advancing eco-friendly wastewater treatment approaches, suggesting promising applications for sustainable practices in industrial contexts. RESEARCH HIGHLIGHTS: This research assessed the effectiveness of phytoremediation using Eichhornia crassipes, Pistia stratiotes, and Arundo donax for removing pollutants i.e. heavy metals (Cd, Pb, Ni, K, Ca, Mg, Na, Fe, Hg) nitrates, phosphates and sulfates from combined industrial wastewater of Hattar Industrial Estate Pakistan. It highlighted the potential of selected plant species' as natural treatment systems, providing crucial insights into their efficiency. Findings contribute to understanding nature-based solutions for complex industrial effluents. NOVELTY: This study harnessed the potential of three macrophytes to tackle industrial effluents, marking their debut in wastewater treatment. By championing environmentally conscious practices, it underscores the need for effective industrial wastewater management while promoting greener and more sustainable approaches within the industrial sector. [ABSTRACT FROM AUTHOR]

AbstractThis research explores the effectiveness of phytoremediation as a sustainable method for sewage treatment, focusing on the performance of Arundo donax in a subsurface vertical flow constructed wetland at the Al-Muamirah treatment station in Hilla, Iraq. The study presents an alternative to conventional sewage treatment systems, particularly suited for resource-constrained regions. Key pollutants such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), and total suspended solids (TSS) were analyzed to assess removal efficiencies. Data were collected over a period from October 2023 to March 2024 using a batch-mode system with an influent flow rate of 0.05276 m³/day (± 0.016 m³/day). Optimal hydraulic retention times (HRT) were identified at 5 days for BOD, COD, and TSS, while TN and TP required extended retention of 8 days due to their reliance on slower microbial and adsorption processes for effective removal. A control unit, lacking plant integration, was used for comparative analysis. The results demonstrated that Arundo donax achieved removal efficiencies of 91% for BOD, 84.28% for COD, 68.37% for TN, 73.42% for TP, and 89.23% for TSS, significantly outperforming the control setup. These findings emphasize the critical role of optimized HRT in enhancing pollutant removal, particularly for nutrients like TN and TP, and underscore the potential of Arundo donax as an eco-friendly solution for wastewater management. [ABSTRACT FROM AUTHOR]

Exurban expansion can degrade significantly stream water quality. This study was conducted on Rock Creek of the Clark's Fork of the Yellowstone River in southcentral Montana, USA. The impact from recent exurban expansion was evaluated by a baseline study measuring total suspended solids (TSS), total phosphorus (TP), total nitrogen (TN) and nitrites (NO2) and nitrates (NO3) together. This was part of a larger study by Montana Department of Environmental Quality to assess water quality, identify sources of pollution and develop total maximum daily loads (TMDL). Water samples were measured for these analytes at nine (2022) and 11 (2023) locations with different land-uses over seven periods (both years). Seasonal spikes, corresponding to runoff (2022, late May), occurred in TSS, TP and TN. Data from 2023 showed similar but reduced levels occurring in June for TSS and TP. Total suspended solids, TP, NO2 and NO3 concentrations increased by location year over year, 2022 to 2023. The high relative concentrations of NO2 and NO3 in Rock Creek are primarily associated with exurban expansion, a significant threat to stream quality and wildlife habitat in Montana. The results will assist county planners in land use decisions. KEY POLICY HIGHLIGHTS: Nitrite and nitrate levels were significantly higher in Rock Creek near exurban areas. Nitrite and nitrate and total phosphorus levels increased 23% and 27%, respectively, from 2022 to 2023. Exurban expansion has accounted for 78% of homes built in our study area, with an accompanied 31,840 acres of habitat loss. Two sites are within the Greater Yellowstone Ecosystem and all sites are within the historic home range for the grizzly bear (Ursus arctos) and wolverine (Gulo gulo). [ABSTRACT FROM AUTHOR]

Multimetric assessment is one of the important tools for diagnosing, detecting and measuring impairment in ecosystem function in lentic ecosystems. It enhances detection capabilities across a broader variety of stressors and offers a more complete picture of ecological conditions than single metrics or biological indicators. In this context, a diatom-based multimetric index (MMI-D) has been developed to evaluate the ecological health of Lake Hawassa. Physicochemical and benthic diatom sampling was conducted at nine sites along the lakeshore, representing varying levels of human disturbance, from February to November in2015 and 2016. The sampling sites were classified a priori into three categories: minimally disturbed (three sites), moderately disturbed (three sites) and highly disturbed (three sites). This classification, was based on a clustering analysis using the percent disturbance score (PDS). Of the 24-diatom candidate metrics, only ten were chosen as core metrics for the development of MMI-D, based on redundancy analysis, reaction to environmental conditions, percent discriminatory efficiency (%DE) and box plots. The newly established MMI-D clearly distinguished between reference and non-reference sites, and between the lake's three clusters. The MMI-D's performance was validated using independent data sets from lakes Hawassa and Ziway and it demonstrated the best capability for discrimination between different disturbance levels. MMI-D 2-stage Least Squares (2SLS) regression analysis revealed an inverse but robust connection with the PDS, indicating its responsiveness to Lake Hawassa habitat quality degradation (n = 9, R2 = 0.921, p < 0.001). The MMI-D revealed a high %DE (95.1%) and a negative but significant connection with nutrients, total suspended solids (TSS), and turbidity (R2 > 0.6; p < 0.05). Generally, it can be concluded that this index is a powerful tool that could assist endusers by providing a practical method for measuring the ecological quality of Lake Hawassa. [ABSTRACT FROM AUTHOR]

The study examined the core, buffer, and transition zones within the Cat Ba Biosphere Reserve in Vietnam to assess changes in five land cover categories (water surface, cropland, vacant land, residential land, and forestland) between 2018 and 2022. Additionally, we aimed to evaluate water quality using three indicators (normalized difference turbidity index, normalized difference chlorophyll index, total suspended solids) and air quality using four indicators (nitrogen dioxide, sulfur dioxide, carbon monoxide, ozone) for the 2022 data. Land cover change analysis and monitoring of water and air quality indicators were conducted using the Google Earth Engine platform, employing Sentinel-2 imagery for land cover and water quality assessment and Sentinel-5P images for air quality assessment. The findings revealed correlations between changes in land cover and water and air quality indicators within the Cat Ba Biosphere Reserve. While occasional instances of values surpassing permissible limits were noted, the average values over the 12-month period in 2022 indicated that water and air quality indicators remained within acceptable thresholds. These results suggest effective preservation efforts in the Cat Ba Biosphere Reserve, indicating no significant signs of degradation. [ABSTRACT FROM AUTHOR]

Chemically enhanced primary treatment (CEPT) is a rapid wastewater treatment process involving treating wastewater with two chemical-aided processes, coagulation, and flocculation. In the present study, a natural extracellular polymeric substance flocculant (EPSBF) produced by Klebsiella pneumonia UKD24, a bacterium isolated from the sewage treatment plant, and a synthetic polyacrylamide anionic polymer flocculant (PAM) were evaluated to treat polluted river water. The synthetic PAM showed immediate turbidity reduction after agitation, while the EPSBF expressed a rapid decrease in optical density. After 20 min of the settling period, the EPSBF showed reduced rates of turbidity, optical density, and chemical oxygen demand at 74.14 ± 5.2%, 89.37 ± 0.76%, and 87.21 ± 0.73%, respectively, while PAM showed 67.08 ± 4%, 85.68 ± 2%, and 86.57 ± 2%, respectively. EPSBF treatment significantly improved the water quality parameters in terms of total dissolved solids, total suspended solids, conductivity, and oxidation–reduction potential than PAM treatment. However, the EPSBF has shown a more water-holding capacity and relatively weak flock formation, producing more sludge volume than PAM. Furthermore, though the sludge produced by the EPSBF treatment had a higher moisture content, it showed shorter capillary suction time (CST). In contrast, sludge formed in PAM treatment had lower moisture content, but it exhibited prolonged CST value indicating that PAM treatment sludge showed slow dewaterability. [ABSTRACT FROM AUTHOR]

This article examines the utilization and advancements of constructed wetlands (CWs) in South Asia (SA), focusing on their roles, costs, and efficacy enhancements through pre- and post-treatment units for various pollutants. Notable findings include Phragmites and Canna species as commonly used macrophytes, achieving high removal rates for various pollutants. CWs consistently remove total suspended solids, biochemical oxygen demand, chemical oxygen demand, emerging contaminants, and antimicrobial resistant bacteria at substantial rates. Anaerobic baffled reactors are effective pretreatment devices for high-strength wastewater. Moreover, CWs exhibit lower operational and maintenance costs compared to conventional treatment methods. However, the bibliometric analysis reveals limited regional cooperation in SA. Key challenges identified include the absence of guidelines for media, vegetation, and maintenance. The review underscores the necessity for further research in optimizing CWs' efficiency through land area management, plant selection, and enhanced design and operation and maintenance protocols. [ABSTRACT FROM AUTHOR]

This study evaluated the performance of a pre-treatment facility for SuDS water quality improvement designed to handle the stormwater runoff of a 200 m2 parking lot, using synthetic runoff and a statistical model of two levels of operation and four variables. The prototype consisted of an inlet ramp, sedimentation and filtration tank, and a recirculation system. The results showed that the removal efficiency of total suspended solids (TSS) and fats and oils concentration in the effluent are not affected by influent variations in flow rate, pH, temperature, TSS, fats and oils, and lead concentration. For the 32 measurements taken, an average of 82.9% (SD 3.6%) was obtained regarding total suspended solids removal. Lead retention possibilities were also observed. The TSS removal efficiencies were above 90.6% for precipitation events, generating peak flows of up to 5 L/s and a duration of 21 minutes, controlling the diffuse pollution peak. [ABSTRACT FROM AUTHOR]

This study evaluated the coagulation/flocculation process using chitosan as a natural coagulant to concentrate suspensions of the cyanobacterium Synechococcus subsalsus and enable biogas production from concentrated biomass. The chitosan performance was tested and compared with the inorganic ferric chloride (FeCl3) coagulant. Using the liquid fraction of the coagulation/flocculation process in subsequent biomass cultivations proved viable, with similar growths in culture media with up to 80% of the liquid fraction. At pH 6 and 400 mg/L FeCl3, the biomass concentrated almost seven times, increasing the total suspended solids (TSS) of the suspension from 0.4–0.6 g/L to 2.6–4.0 g/L. With 80 mg/L chitosan and pH 7, the TSS concentration attained values in the range of 7.0–9.7 g/L, an increase of more than 30 times, clearly showing that chitosan has a much higher capacity for biomass concentration at a lower concentration. A ratio of 0.3 g chitosan/g dry mass of the biomass was established to reach the maximum densification. The production of methane from chitosan-densified biomass proved to be feasible. Chitosan-densified biomass showed a two-phase cumulative methane production when digested, with slower methane production and 23% lower methane yield after 30 days of digestion (207 NmL CH4/g CODi) compared to the biomass from cultivation (non-densified, 270 NmL CH4/g CODi). However, optimizing the digestion conditions of the densified biomass should increase the methane yield and reduce process time. [ABSTRACT FROM AUTHOR]

Industries generate hazardous dye wastewater, posing significant threats to public health and the environment. Removing dyes before discharge is crucial. The ongoing study primarily focused on synthesizing, applying, and understanding the mechanism of green nano-biochar composites. These composites, including zinc oxide/biochar, copper oxide/biochar, magnesium oxide/biochar, and manganese oxide/biochar, are designed to effectively remove Actas Pink-2B (Direct Red-31) in conjunction with constructed wetlands. Constructed wetland maintained pH 6.0–7.9. At the 10th week, the copper oxide/biochar treatment demonstrated the highest removal efficiency of total suspended solids (72%), dissolved oxygen (7.2 mg/L), and total dissolved solids (79.90%), followed by other biochar composites. The maximum removal efficiency for chemical oxygen demand (COD) and color was observed at a retention time of 60 days. The electrical conductivity also followed the same order, with a decrease observed up to the 8th week before becoming constant. A comprehensive statistical analysis was conducted, encompassing various techniques including variance analysis, regression analysis, correlation analysis, and principal component analysis. The rate of color and COD removal followed a second-order and first-order kinetics, respectively. A significant negative relationship was observed between dissolved oxygen and COD. The study indicates that employing biochar composites in constructed wetlands improves textile dye removal efficiency. The novelty of this study is the selection of Cymbopogon as a proper plant for phytoremediation of dye along with green metal oxide coated biochar. These were selected due to their good ability to remove organic pollutant. This study demonstrates the uptake and degradation processes of persistent dye in constructed wetland. [ABSTRACT FROM AUTHOR]

Green fabrication of nanoparticles (NPs) is simple, pocket-friendly, easy, sustainable, and devoid of eco-toxicity issues. Thirty-five bacterial strains were isolated from 'tie and dye' effluent-contaminated soil and effluent samples and were identified using traditional methods. Following a dye decolourization assay, Proteus mirabilis strain (NG-ABK-32) emerged as the isolate with the highest potential to decolourize vat violet RR dye. Titania nanoparticles (TiO2 NPs) fabricated using NG-ABK-32 strain were characterized by UV-visible spectroscopy (UV-vis), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), and Fourier Transform Infrared (FT-IR) spectroscopy. UV-Vis result displayed an absorption peak at 320 nm. The TEM image revealed monodispersed, spherical NPs possessing an average particle size of 3.18 nm. The crystallographic plane of rutile TiO2 NPs and high purity were confirmed by the XRD pattern. The average crystallite size was 52.53 nm. The synthesis of TiO2 NPs was further established from FT-IR by the presence of Ti-O, Ti-OH, and O-Ti-O functional groups. The synergistic treatment caused a significant reduction of total suspended solids (TSS), total dissolved solids (TDS), biological oxygen demand (BOD), chemical oxygen demand (COD), and color (Pt.Co) of the effluent by 96.86%, 78.78%, 67.84%, 56.65%, 67.84%, and 72.09% respectively. Thus, this study confirmed the better efficiency of combining biological (NG-ABK-32) pre-treatment with photocatalytic degradation post-treatment using the synthesized TiO2 NPs in the treatment of 'tie and dye' effluent compared to the application of the TiO2 NPs as a single treatment method. [ABSTRACT FROM AUTHOR]

Dissolved Air Flotation (DAF) systems are designed to remove oil and grease (O&G) and total suspended solids (TSS) in wastewater treatment. These systems require saturation tanks, water pumps, and high-pressure compressors to control the pressure, hydraulic retention time, and airflow parameters. DAF process efficiency depends on complex operational controls associated with these components, and the most critical aspect of an effectively operating DAF unit is a generated bubble size. This work presents the design and operational test of a flotation unit prototype that replaces the saturation tank and high-pressure compressors present in DAF with the CARMIN microbubble injector, the evaluation of the proposed system's TSS and O&G removal efficiency was carried out considering different initial configurations of the injector to change the generated microbubble size, four synthetic wastewater solutions, and poly aluminum chloride as a flocculant to establish the potential of this system for the poultry processing wastewater treatment. Mean microbubble size results were obtained from 47.41 µm to 116.17 µm. The average removal efficiency of TSS exceeded 65% under a high concentration of suspended particles (1,560 mg/l) and 80% under a lower TSS concentration (795 mg/l). Meanwhile, 70% and 90% of O&G were removed from high (400 mg/l) and low (100 mg/l) initial O&G concentrations, respectively. These removal levels are similar to those reported in the literature for DAF for poultry processing wastewater, albeit with a simple configuration and better controllability and scalability. [ABSTRACT FROM AUTHOR]

Inland and coastal environments are complex ecosystems composed of suspended and dissolved materials, affecting light propagation within the water column. Satellite-based water quality research relies on water optical properties provided by optical sensors on board of polar orbit satellites since the 1980's. Specifically, Geostationary (GEO) ocean colour satellites offer high temporal resolution (e.g. every 15-minute observations), moderate spatial resolution (0.5–1 km) at regional scale, making them a promising alternative to polar orbiting satellites for near-continuous monitoring of highly dynamic aquatic ecosystems. This literature review examines the evolution of geostationary satellite technology and its applications in monitoring inland and coastal waters. A summary of the most relevant studies using geostationary sensors is provided for key water quality indicators such as chlorophyll-a and algal organisms, total suspended solids, and turbidity. Also, geostationary missions were well-detailed, with their available sensors and characteristics. Although this research topic is still incipient, recent studies have demonstrated the potential of GEO multi-spectral observations in understanding sub-daily water quality patterns. Notably, most research studies have focused on Asia, suggesting unexplored opportunities globally. Advanced Himawari Imager (AHI) and Geostationary Ocean Colour Imager (GOCI) have been used to improve water quality estimates, and inherent challenges were documented, such as algorithm validation, limited spatial resolution, and high volume of images and auxiliary files to be managed. The opportunities for new studies range from algorithm development for atmospheric correction, cloud masking, and bidirectional reflectance corrections to inter-comparison with existing sun-synchronous satellites. Geostationary satellites are promising avenues for future research on near-continuous monitoring of inland and coastal water resources. [ABSTRACT FROM AUTHOR]

Sub-Saharan Africa faces a number of essential issues, including water quality. As such, evaluating the surface water quality of lakes and reservoirs is a crucial part of environmental monitoring and management. Especially in a region where these water bodies serve as a source of livelihood for communities living around them. Water quality parameters (WQPs) are usually taken from the site and sent to the laboratory for measurement and analysis. However, this traditional method is time-consuming, costly, and labor-intensive. Combining geographic information system and remote sensing (RS) allows researchers to analyze WQPs more conveniently. This study, therefore, used RS technology to map and estimate WQPs and correlated it with in-situ measurement. Using the empirical regression model and Landsat 8, WQPs such as chlorophyll-a (Chl-a), total suspended solids (TSS) and turbidity were estimated. The results from RS were correlated with the in-situ measurements of water quality. The results showed that the in-situ Chl-a levels varied from 0.206 to 13.5 mg/L, averaging 5.1 mg/L. The Chl-a values estimated from Landsat 8 had R2 of 0.883 and 0.853, respectively, for both periods (17 December 2022 and 16 March 2023). The green band (B3) was more instrumental in detecting Chl-a. The in-situ measurement for TSS ranged between 18 and 48 mg/L, with a mean value of 28.7 mg/L. These readings were low and within tolerable bounds of 50 mg/L. High TSS concentrations were found near farms and communities with a significant influx of silt into the surrounding lake. The comparison of in-situ water quality and the reflectance from satellite data showed that the turbidity estimated from the sensor from the two periods has R2 > 0.65. The study showed that the combination of the Landsat image and in-situ measurement offers great ways to provide timely and affordable estimation from WQPs. [ABSTRACT FROM AUTHOR]

The effect of coagulant dosage in a chemically enhanced primary treatment (CEPT) on the performance of a conventional wastewater treatment plant (WWTP) has been investigated. Lab-scale experiments simulations were carried out in order to evaluate the effect of coagulant addition on the primary settling performance. In these experiments, FeCl3 was used as coagulant. Later, the WWTP was theoretically simulated using a commercial software (WEST®) to evaluate the effect of coagulation/flocculation on the global system, based on the results obtained at lab-scale. According to these results, the CEPT modifies the organic matter balance in the WWTP, decreasing the contribution of readily (SS) and slowly (XS) biodegradable fractions of COD to the aerobic biological process up to 27.3% and 80.8%, respectively, for a dosage of FeCl3 of 24 mg L−1. Consequently, total suspended solids in the aerobic reactor and the secondary purged sludge decreased up to 33% and 13%, respectively. However, the influence on effluent quality was negligible. On the contrary, suspended solids concentration in the sludge to be treated by anaerobic digestion increased, mainly regarding the Ss and Xs fractions, which caused an 8.1% increase in biogas production potential, with approximately 60% of CH4 concentration. [ABSTRACT FROM AUTHOR]

The pollution indices of microplastic content in bottled water from South Eastern Nigeria were evaluated. Microplastic contamination factors, pollution load and risk index, polymer risk indices and estimated daily intake for adults and children were determined. Microplastic concentrations, types and shapes were assessed using scanning electron microscopy (SEM) – energy-dispersive X-ray spectroscopy (EDS). From documented literature, this is the first study on microplastics in bottled water from Africa. The microplastics were found in 92% of the samples. The four types of microplastics were polyethylene (PE), polyvinyl chloride (PVC), polyethylene terephthalate (PET) and polydimethyl siloxane (PDMS) while the dominant shapes were fragment, film and pellet/granule. Principal component analysis shows strong association of the concentration of microplastics with total solids and total suspended solids. Pollution risk indices show medium pollution risks of microplastics in bottled water. The estimated daily intake was generally low and therefore shows no risk from daily consumption but reveals a higher intake of microplastics for children than adults. The source of the MPs was attributed to leaching from the packaging material, which should be monitored by appropriate regulatory bodies. [ABSTRACT FROM AUTHOR]

The aim of this study is to evaluate the performance of coagulation and flocculation (C/F) process and economic analysis for the advanced primary treatment in order to obtain a semi-closed water circuit in the pulp mills in the cardboard recycling industry. Since the high water quality level is not required in the pulpers, the dosages in this research were determined without pH changes or adjustment to decrease the capital and operational expenditures. The results showed that FeCl3 with the concentration of 2000 mg/L gave the best quality when coagulants were used solely. Moreover, using alum with the concentration of 1500 mg/L provided acceptable quality for the effluent re-circulation and the removal/reduction percentages of 42, 82, 71 and 97 were achieved for chemical oxygen demand (COD), total suspended solids (TSS), turbidity and colour, respectively. It was also found that the combination of coagulants did not improve the process performance significantly. The best combination was ferric chloride (500 mg/L) and alum (2000 mg/L) with the efficiency of 47% and 98% in terms of COD and colour removal/reduction, respectively, while the best couple in TSS removal was FeCl3 (500 mg/L) and CaCO3 (500 mg/L) with the efficiency of 88%. The chemicals coupled with cationic polyacrylamide (C-PAM) did not enhance the quality of pre-treated solutions when the settling time reduced up to 15 minutes. The cost analysis also showed that alum is the most cost-effective coagulant with the costs in the range of 0.06–0.12 $/kg removed TSS, 0.06 to 0.11 $/kg removed COD and 0.06–0.1 $/m3·reduced NTU whereas calcium carbonate is the economic coagulant regarding colour reduction with the cost of 0.003 $/m3·reduced unit and more than the reduction efficiency of 90%. [ABSTRACT FROM AUTHOR]

The Anwai River is the most important river in Asaba, Nigeria, because of its many uses, and these include abattoir activities. The aim of this study was to assess the surface water and surrounding soil of the Anwai River for the effects of abattoir activities during the wet and dry seasons of 2020. The quality of soil and water samples was analysed using standard procedures as set by the American Public Health Association. Results of water analyses showed that pH, total dissolved solids and total suspended solids varied from 6.45 to 6.67, 13.50 mg L−1 to 24.42 mg L−1, and 2.19 ± 0.04 mg L−1 to 10.79 mg L−1, respectively. Soil pH, total organic content, Pd and Cr had a range of 5.83 to 7.65 pH units, 0.15 to 2.74%, 1.88 ± 0.03 to 22.8 ± 0.28 mg kg−1, and 0.86 ± 0.03 to 4.87 ± 0.04 mg kg−1, respectively. There were significant differences between Upstream, Midstream (by the abattoir) and Downstream samples; however, there were no significant differences between dry and wet season results for most of the parameters. Midstream values for the water quality index were 104.89 and 119.34 in the dry and wet seasons, respectively, which showed that the Midstream water samples were poor. The findings of this study showed that the abattoir activities were negatively impacting river water and soil quality. [ABSTRACT FROM AUTHOR]

This review paper describes different control applications for the A2/O process in sewage wastewater treatment plants. The contents elucidate the research carried out in the literature related to the design of different types of controllers for controlling different variables such as dissolved oxygen, nitrate, total suspended solids, ammonia, etc. that are responsible for the simultaneous removal of both nitrogen and phosphorus. A comprehensive analysis is carried out based on the important factors for the implementation of the control systems with critical discussion and achievements. Control strategies range from simple controllers such as proportional–integral (PI) to the latest (advanced) control approaches such as model-based predictive, fuzzy logic, artificial neural network, and optimal controllers. A distributed control system applied to the A2/O pilot plant is also elucidated. A summary of comparisons between different control systems are assessed and reported in this review. [ABSTRACT FROM AUTHOR]

Understanding the major drivers of runoff water quality in urban areas is important for sustainable water management. In this study, runoff water quality in a catchment in Colombia and another in Brazil was monitored and related to rain, and meteorological variables through correlation and principal component analysis. High correlations were found between event mean concentration of total suspended solids (TSS) and total phosphorus (TP), as well as with total Kjeldahl nitrogen (TKN) and total organic carbon (TOC). The results indicated that TSS and TP were related to sediment transport in the catchment, while NTK and TOC were derived from point sources (improper wastewater disposal). Rain depth, maximum specific discharge, air temperature, and solar radiation were the main factors explaining variability of water quality. These results contribute to a better understanding of local processes driving runoff water quality, and bring valuable insights for modelling and management of stormwater in urban catchments. [ABSTRACT FROM AUTHOR]

Low impact developments (LIDs) are control measures to restore the hydrologic regime and enhance stormwater quality. Due to LID's expensive capital and maintenance cost, the placement of LID controls in a watershed is an important planning task and still an open question in the specialized literature. This study proposes a simulation-optimization approach to place bioretention systems within a watershed to optimize their effectiveness. The Stormwater Management Model (SWMM) and the Non-dominated Sorting Genetic Algorithm III (NSGAIII) were coupled to identify the near-optimal locations of bioretentions for near-optimal quality and quantity controls, considering runoff volume, peak flow, total suspended solids, total nitrogen, and cost. Trade-offs were identified between cost versus other objective functions. The results suggest no specific spatial preference in placement of bioretentions under different rainfall regimes in watershed scale. However, in subcatchment scale, the near-optimal placement under single storm events is either maximum or none, while distributed under continuous simulation. [ABSTRACT FROM AUTHOR]

In Ghana, small-scale mining (SSM) has been carried out for many years, generating employment and income. Currently, illegal artisanal mining ('galamsey') has impacted the environment negatively, resulting in land degradation and water pollution. The government of Ghana, responding to public outcry against the negative effects of 'galamsey', placed a ban on illegal small-scale mining activities in March 2017. This ban stopped both 'legal' small-scale and the illegal artisanal miners from carrying out any such activity. In July 2018, this study was carried out to examine the status of water and sediment quality in eight endemic regions of illegal mining to ascertain the outcome of the ban on the water quality of the rivers. Methodologies in the Standard Methods for the Examination of Water and Wastewater were followed. Results of the study indicated that the rivers were high in total suspended solids (TSS), turbidity and colour, suggesting inflow of wastewater from the illegal mining activities and some run-off. Colour had a strong correlation with turbidity (r = 0.95) and TSS (r = 0.94), suggesting that the pollution originates from the same sources. Low levels of metals were found in both water and sediment. However, very high concentrations of Fe were detected in both water and sediment. Mercury concentrations were low in the water column but relatively higher in the sediment. A comparison of the general water quality status of the water bodies in the Pra Basin in 2013 and 2018 using the Water Quality Index (WQI) showed a marginal improvement in quality in 2018 over 2013 in the Pra Basin. The improvement of water quality in 2018 is attributable to the ban. [ABSTRACT FROM AUTHOR]

This study investigated the water recovery of real textile wastewater by Coagulation/Flocculation (CF) integrated with Direct Contact Membrane Distillation (DCMD). The proof-of-concept tests were studied with synthetic solutions of reactive and disperse black dyes at different concentrations, and real textile wastewater from the discharge machine and the equalization tank. Results showed that CF-DCMD exhibited higher permeate fluxes (up to 40%) than single DCMD and maximum color rejection rates (100%). Moreover, CF-DCMD enabled water reclamation from cotton and polyester dyeing wastewater which was not possible by MD (Membrane Distillation). The integrated system showed excellent chemical oxygen demand removal capacity, total suspended solids, turbidity, conductivity reduction, and removed any signs of toxicity from the tested wastewater. The coagulation/flocculation process prior to the MD reduced the fouling factor for all wastewater, highlighting the equalization tank where a reduction of around 72% was observed, achieving the goal of reducing fouling and increasing the efficiency of the MD. Membrane characterization indicated that CF-DCMD confirmed less fouling of membranes than single DCMD. Thus, this study allows to understand the potential and robustness of the CF-DCMD process in the treatment of textile wastewater and that it is possible to develop alternative technologies to treat complex wastewater effectively. [ABSTRACT FROM AUTHOR]

This study assessed the spatio-temporal dynamics of the phytoplankton community in backwaters of the Ketar River, central Ethiopia, in relation to water quality and macrophyte coverage. Phytoplankton samples and physicochemical information were collected at six sites along the river over 1 year (December 2017 to November 2018). Phytoplankton was collected using a 15-μm mesh net. A total of 56 species belonging to three algal phyla were identified; the most diverse phylum was Bacillariophyta (35 species), followed by Chlorophyta (13 species) and Euglenophyta (eight species). Bacillariophyta had the highest abundance and contributed 80.08% of the total phytoplankton abundance. Site 6 in the downstream portion had the highest abundance and greatest diversity of phytoplankton species. The algal phyla present showed significant differences in species diversity and abundance both spatially and temporally. Redundancy analysis results revealed that the spatial distribution of phytoplankton in the river positively correlated with pH, electrical conductivity, dissolved oxygen and nitrate-nitrogen, while water temperature and total suspended solids correlated negatively. Some indicators of organic pollution suggest that the water quality of the river is progressively declining, meriting close monitoring. [ABSTRACT FROM AUTHOR]

Hydraulic fracturing oil- and gas-produced water is frequently highly impaired. While it is often deep well injected, there is a great deal of interest in treating and recovering this water for beneficial uses. However, multiple-unit operations are needed if these wastewaters are to be recovered. Electrocoagulation is considered a promising pretreatment technology. Herein, we have investigated the use of aluminum electrodes for electrocoagulation as a pretreatment operation. The effects of electrode arrangement, applied current, reaction time, pH and inter-electrode distance on the quality of the treated water have been investigated. The results obtained here indicate that electrocoagulation can obtain good removal of turbidity (95%), total suspended solids (TSS) (90%) and total organic carbon (TOC) (69%) by carefully choosing the reaction conditions. Sedimentation was used to separate the treated water from the sludge. The performance of the electrocoagulation process depends strongly on the quality of the feed water. The viability of a practical continuous electrocoagulation process will depend on the volume (footprint) of the reactor, which in turn will depend on operating conditions and the quality of the feed water. [ABSTRACT FROM AUTHOR]

The microwave enhanced advanced oxidation process (MW-AOP) has been applied to pre-treat different sludge types and high solids content. Secondary sludge not only had the highest solids and nutrient content but also yielded higher treatment efficiency than primary or mixed sludge. In the case of secondary sludge with 4% total solids (TS), the total suspended solids (TSS) concentration was reduced by 32% while soluble chemical oxygen demand concentration increased from 1% to 40% after treatment at 110°C. A high level of nutrient release was also achieved; about 65% total phosphate (TP) solubilized at 110°C. The degree of secondary sludge disintegration was dictated by temperature and hydrogen peroxide dosage. The optimal operating temperature for the system was 110°C, and sludge containing TS up to 8% was treated effectively. Secondary sludge with 8% TS had a TSS reduction of 41% after treatment at 110°C while COD solubilization was about 45%; about 55% TP was solubilized at 10 min holding time. Treatment of sludge with higher solids content would allow for handling larger amounts of sludge at a given period and reduce heating cost per unit of treated sludge. The inter-relationship between the degree of sludge disintegration and changes in chemical and physical properties was also clearly demonstrated here. The treated sludge would be an ideal substrate for anaerobic digestion or phosphorous recovery processes. High levels of nutrients (phosphorus and nitrogen) and metal release, and solids disintegration from sludge containing high solids content would make subsequent resource recovery processes more effective and economical. [ABSTRACT FROM AUTHOR]

This study was focused on the capacity investigation of a novel multistage flexible fibre biofilm reactor (MS-FFBR) to treat milk processing wastewater (MPW) with high organic loading (OLR). The MS-FFBR performance was evaluated at four intermediate stages separately, and also the final effluent quality of the overall system with an influent chemical oxygen demand (CODin) ranged from 1500 ± 20 to 6000 ± 50 mg/L and hydraulic retention times (HRTs) of 8, 12, and 16 h. By comparting the bioreactors into the four stages effectively enhanced the bioreactor's performance. The maximum TCOD removal efficiency was achieved at the first stage, which was about 89 ± 20, 82 ± 20, and 78 ± 20% at HRTs of 16, 12, 8 h, and low CODin of 1600 ± 20, 1590 ± 20, and 1673 ± 20 mg/L, respectively. However, the first stage had less contribution to TCOD removal at high CODin concentrations, reported to be about 42 ± 4%, 46 ± 4%, and 25 ± 4% at CODin of 5960 ± 40, 5830 ± 40, and 5870 ± 40 mg/L, respectively. Furthermore, the MS-FFBR was effective in removing total suspended solids (TSS) and turbidity. The bioreactor has reduced the effluent turbidity to 9.0 ± 0.2, 20.0 ± 0.6, and 16.1 ± 0.5 NTU at low CODin concentrations of 1600 ± 20, 1590 ± 20, and 1670 ± 20 mg/L and HRTs of 16, 12, and 8 h, respectively. The bioreactor revealed a high COD removal rate increased from 2.3 ± 0.1 to 12.2 ± 0.4 kg TCOD/m3d by increasing the OLR from 2.4 ± 0.1 to 17.6 ± 0.4 kg TCOD/m3d, confirming high reactor capacity for treatment of high-strength wastewater. Kinetic studies confirmed that the biomass yield was low at various HRTs ranging from 0.1 to 0.2 gVSS/gCOD. [ABSTRACT FROM AUTHOR]

A combination of discrete sampling using autosamplers triggered by area-velocity metres and continuous water quality monitoring using YSI datasondes enabled us to evaluate the dynamics of both stormwater runoff and dry weather water quality associated with an urban park and WSUD treatment train in Singapore. The WSUD treatment train consisted of a raingarden and sedimentation ponds. A first flush phenomenon was observed for total suspended solids (TSS) in three of four discrete-sampled events, but there was a less pronounced first flush characteristic for nutrients. Mean TN concentrations associated with runoff from the park (upstream of the WSUD treatment train) were in the range that would be associated with eutrophic conditions, while mean TP levels were in the mesotrophic/eutrophic boundary range. The raingarden reduced nutrient and TSS levels by 7–62% and loads by 65–93%, although nitrate levels were higher in the effluent compared to the influent. The sedimentation ponds successfully reduced sediment levels by 56%, based on continuous turbidity measurements. The dissolved oxygen levels in the sedimentation ponds were lower during drought periods, which has implications for aquatic organisms. The WSUD treatment train generally improved runoff quality from the park and such features can be easily integrated into the park design. [ABSTRACT FROM AUTHOR]

The amount of total suspended solids (TSS) is the most visible indicator for evaluating water quality in reservoirs. Previous investigations paid more attention to TSS of the surface layer in reservoirs, while suspended particles are prone to settle, resuspend, and aggregate at the bottom of reservoir. There may be different patterns of the TSS in different depths. This study is to assess the TSS concentration by weight analysis, find the evidence of the existence of flocculated suspended particles by in situ underwater imaging analysis, and discuss the impact of the flocculation process of suspended solids on water quality in deep reservoirs. Although the TSS concentration is lower than other reservoirs with the same trophic level, many flocs were found at the bottom of the deep-water area (> 15 m) in the Biliuhe Reservoir according to the recordings of the in situ underwater camera. The further comprehensive analysis demonstrates that the fine particle in flood season and resuspension is the main source of suspended flocs at the bottom of the reservoir. While the slow settling velocity results in the flocculation of fine suspended particles and long-term residence in the bottom layer of the reservoir. TSS has a significant correlation with iron and total phosphorus. Resuspension, flocculation, and settling impact on the transport of suspended sediment and associated contaminants. The evidence from this study suggests that the impact of flocs on water quality should be further discussed to ensure water supply safety. Total suspended solids (TSS) in reservoirs are the most visible indicators of water quality. Usually, more investigations are carried out on the surface layer of reservoirs. Suspended particles are prone to aggregate and settle at the bottom of reservoirs. Hence, it is significant to explore the temporal and spatial characteristics of suspended solids in different depths of reservoirs. This study is to assess the TSS concentration by weight analysis and in-situ underwater imaging analysis and discuss the impact of the flocculation process of suspended solids on water quality in deep reservoirs. It was found that TSS has a significant correlation with iron and total phosphorus. Also, the recordings of the in-situ underwater camera show that many flocs were found at the bottom of the deep-water area (> 15 m) in the Biliuhe Reservoir. The relation between logarithm of the projected area ratio of flocs with water depth shows a quadratic equation trend. The further comprehensive analysis demonstrates that the fine particle in flood season and resuspension from reservoir erosion-sedimentation transition zone is the main source of suspended flocs at the bottom of the reservoir. Most of the flocs settled 5.3 and 7 m/d at 4°C and 14°C, respectively, which would take about 5–6 days to reach the bottom. The slow settling velocity of fine particles is the main reason for the flocculation of suspended solids and long-term residence in the bottom layer of the reservoir. The evidence from this study suggests that the impact of flocs on water quality should be further discussed to ensure water supply safety. [ABSTRACT FROM AUTHOR]

Oil interceptors are traditional SuDS devices used in highway runoff treatment to remove both floatable impurities (leaves, oil) and total suspended solids (TSS). This paper presents the results of an examination of the performance of an oil interceptor based on particle size distribution (PSD) and TSS during three rainfall events. The interceptor is situated on one of the busiest motorways in the UK (where peak traffic flow is 30,000 vehicles per hour). Although the overall data collected for this study provided evidence that the interceptor removed, in most cases, 70% of TSS, the data for particle size distribution (PSD) showed that the interceptor did not always cope with particle separation for particles of less than 25 μm diameter. [ABSTRACT FROM AUTHOR]

Understanding of shoreline dynamics is essential to coastal management and the development of tropical archipelagic countries. Therefore, this study aims to analyze the factors affecting shoreline changes and their future predictions in Bengkayang Regency, West Kalimantan. Research data used includes historical maps, remote sensing imagery, total suspended solids, underwater slope and depth, distance from the estuaries, wind speed, and distance from the coastal constructions. The multiple linear regression models and digital shoreline analysis system were applied. Findings showed accretion occurred in 1981, 1991, and 2021 while abrasion was detected in 2001 and 2011. The shorelines gained 37.05 meters between 1945 and 2021 under intensive accretion in segments 2–4 while abrasion recorded in segments 6–8. Furthermore, the shorelines are projected to be abraded between 2021 and 2041. These findings are recommended to be considered in the development of coastal areas that are adaptive to climate change, sea-level rise, and land subsidence. [ABSTRACT FROM AUTHOR]

It is critical to monitor water quality to keep water bodies ecologically healthy and facilitate the sustainable development of Kenyir Lake. Water quality differs temporally and spatially and is affected by several factors. Typically, water quality inspection systems are cost- and labour-intensive depending on water quality indicator count and sampling frequency. Optimising the frequency and location of water quality sampling is crucial. This study focused on collecting water samples from 22 locations in Kenyir Lake during different seasons (normal, dry, and wet). The study aimed to assess the spatial and temporal variations in the water quality of Kenyir Lake based on multivariate statistical methods. In this study, the following water quality parameters were selected for analysis: temperature, dissolved oxygen (DO), pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and ammoniacal nitrogen (NH3-N). In addition, a water quality index was also calculated. GIS software was used to assess water quality data, and various multivariate statistical methods like cluster analysis (CA), discriminant analysis (DA), and principal component analysis (PCA) were employed. The outcome shows minor spatial differences concerning Kenyir Lake; however, the temporal variations were noteworthy during this study duration. Cluster analysis divided the locations into 3 clusters with TSS being key parameter affecting the spatial differences in water quality. Stepwise discriminant analysis based on three parameters, pH, temperature, and TSS, produced the associated classification matrix that correctly estimated 69.7% of the input. NH3-N and TSS were found to be the two critical aspects that affect water quality during dry, wet, or normal climatic conditions. [ABSTRACT FROM AUTHOR]

The traditional leather industry releases different chemical wastes into the environment, which calls for the use of alternative, nonpolluting processes. The use of biological catalysts in industrial processing has received a great deal of attention in recent years, mainly for environmental reasons. The main objective of this study was to produce and characterize keratinase enzyme from Bacillus subtilis ES5 and evaluate its potential application for leather dehairing. The gene encoding keratinase was validated with a fragment length of approximately 1100 bp. The keratinase exhibited maximum activity at temperature and pH of 45 °C and 8, respectively. Among the tested metal ions, Ca2+ and Mg2+ improved keratinase activity by 132.56 and 111.78%, respectively, at concentrations of 5 mM. β-mercaptoethanol enhanced keratinolytic activity. However, ethylenediaminetetraacetic acid (EDTA) significantly inhibited it, indicating that the enzyme is a member of the metalloprotease family. It completely dehaired goat/sheep skins within 14 h, resulting in decreased biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total dissolved solids (TDS), total suspended solids (TSS), and overall pollution load by 57.39, 70.53, 93.59, 94.90, and 79.10%, respectively. The results demonstrated the pivotal advantages of this keratinase, addressing environmentally friendly processing and sustainable solid waste management. The improved properties of enzyme-treated dehaired pelts suggest that crude keratinase could be used in ecologically friendly holistic leather manufacturing to avoid the pollution issues associated with the use of chemicals. [ABSTRACT FROM AUTHOR]

Recent studies point out losses of 30–40% of the produced methane in the effluent of anaerobic reactors treating sewage, reducing the renewable energy potential and the environmental footprint. A novel bench-scale upflow anaerobic hybrid (UAHB) reactor combining a sludge blanket at the bottom and a filter media at the top, both with three-phase separators, was proposed to evaluate the recovery of dissolved methane. UAHB was operated with volumetric organic loading rate of 1.24 kg COD m−3 d−1 and hydraulic retention time of 8 h for 218 days to evaluate the influence of temperature (18°C, 23°C, and 28°C) in the methane dissolved in the effluent and collected from three-phase separators. Chemical oxygen demand (COD) and total suspended solids (TSS) removals efficiencies remained constant during the operation and equal to 90 and 95%, respectively, related to the activity of biomass retained in the filter media. Temperature increase influenced more the methane production in the sludge blanket rather than in the upper bed. The volume of recovered methane increased about 20% with the installation of the support media and the upper three-phase separator (3PHS). The loss of methane dissolved in the effluent was strongly influenced by the temperature, and higher with the decrease of this parameter. Non-statistically significant correlations were observed between the temperature and the methane production in the upper bed (p-value = 0.0943) and total (p-value = 0.0930). Thus, it can be concluded that the evaluated temperatures did not influence the global efficiency and the total methane yield of the UAHB reactor. [ABSTRACT FROM AUTHOR]

The membrane for wastewater decontamination is an interesting alternative to conventional layered adsorbent filtration systems. Membrane bioreactors (MBRs) remove the residual biomass on the surface of the membranes irrespective of the settling properties of the sediment. Therefore, a high waste concentration as well as a low nutrient/microorganism ratio is required. In addition, the development process of a characteristic Layer Adsorption Filtration System (LAFS) community is favoured by the special properties of MBRs. This study will study the operating and treatment performance of MBR and infiltration processes and compare them with each other. The calculation was made using GPS-X software. The quality of the effluent received by the MBR system was better or equivalent to that obtained by adsorbent layer filtration (ALF). The main significant difference was the removal of total suspended solids (TSS), which reached up to 96% and also, organic matter in the MBR. [ABSTRACT FROM AUTHOR]

Predicting the infiltration rate (IR) of treated wastewater (TWW) is essential in controlling clogging problems. Most researchers that predict the IR using neural network models considered the characteristics parameters of soil without considering those of TWW. Therefore, this study aims to develop a model for predicting the IR based on various combinations of TWW characteristics parameters (i.e. total suspended solids (TSS), biological oxygen demand (BOD), electric conductivity (EC), pH, total nitrogen (TN), total phosphorous (TP), and hydraulic loading rate (HLR)) as input parameters. Therefore, two different artificial neural network (ANN) architectures, multilayer perceptron model (MLP) and Elman neural network (ENN), were used to develop optimal model. The optimal model was selected through evaluating three stages: selecting the best division of data, selecting the best model, and deciding the best combination of input parameters based on several performance criteria. The study concluded that the first combination of inputs that include all the seven-parameter using MLP model associated with 90% division of data was the optimal model in predicting the IR depending on TWW characteristics parameters, achieving a promising result of 0.97 for the coefficient of determination, 0.97 for test regression, 0.012 for MSE with 32.4 of max relative percentage error. Abbreviations: IR: Infiltration Rate; TWW: Treated Wastewater; TSS: Total Suspended Solids; BOD: Biological Oxygen Demand; EC: Electric Conductivity; HC: Hydraulic Conductivity; TN: Total Nitrogen; TP: Total Phosphorous; HLR: Hydraulic Loading Rate; ANN: Artificial Neural Network; MLP: Multilayer Perceptron Model; ENN: Elman Neural Network; FFANN: Feedforward Artificial Neural Networks; R: Regression Values; SAR: Sodium Adsorption Ratio; DOC: Dissolved Organic Carbon; ANAMMOX: Anaerobic Ammonium Oxidation; CEC: Cation Exchange Capacity; BPNN: Back Propagation Neural Network; GRNN: General Regression Neural Networks; ELM: Extreme Learning Machine Neural Networks; TDNN: Time Delay Neural Network; TLRN: Time Lag Recurrent Network; NGWTP: North Gaza Wastewater Treatment Plant; MASL: Meters Above Sea Level; DNC: Dynamic Node Creation; PWA: Palestinian Water Authority; RBF: Radial Basis Function; ANFIS: Adaptive Neuro Fuzzy Inference System; BD: Bulk Density; RMSE: Root Mean Square Error; MAE: Mean Absolute Error; MSE: Mean Square Error; R2: Determination Coefficient; LLR: Local Linear Regression; DLLR: Dynamic Linear Regression; MNN: Modular Neural Networks; RNN: Recurrent Neural Network; NARX: Nonlinear Autoregressive with Exogenous input network; WNN: Wavelet Neural Networks [ABSTRACT FROM AUTHOR]

Hydraulic behavior and pollutant removal efficiency of three stormwater end-of-pipe control structures were evaluated and compared. Three detention basins (wet, dry, and semi-dry, i.e. dry with a wet central channel) were monitored within three sites of Southern Quebec, Canada. Water samples were collected upstream and downstream of the basins and analyzed for total suspended solids (TSS), nitrogen, total phosphorous, and ions related to de-icing salts. Generalized linear models and hydrological/hydraulic (SWMM) models were developed to compute the long-term TSS and total phosphorous load removal efficiency for two of the studied basins. Results indicate that even when considering uncertainties, removal rates are the highest for the wet basin and the lowest for the dry one. The addition of a wet channel in the semi-dry basin leads to higher removal efficiency than in the dry basin (e.g. median TSS concentration removal of 69% and 14%, respectively, for the semi-dry and dry basins). [ABSTRACT FROM AUTHOR]

Tofu is widely processed in East and Southeast Asian countries. During the production, highly polluted wastewater is discharged. This wastewater is commonly treated using a high-rate anaerobic wastewater treatment process; however, several organic compounds and nitrogen remain in the anaerobic effluent. The aim of this study was to develop a combined upflow anaerobic sludge blanket (UASB) and downflow hanging sponge (DHS) biosystem that that serves as a post-treatment for an expanded granular sludge blanket reactor used for treating tofu-processing wastewater in Japan for 699 days. The UASB reactor played a role in treating of COD, with 58 ± 16% and 74 ± 20% of total COD and soluble COD removed anaerobically. Besides, methane was recovered from removed soluble COD were 63 ± 28% and 87 ± 64% at winter and summer. Meanwhile, the DHS reactor showed its potential in treatment of BOD and TSS. The final effluents were recorded as 67 ± 38 mg L−1, 50 ± 26 mg L−1, and 22 ± 16 mg L−1 of total COD, BOD and total suspended solids, respectively. This indicates that the proposed UASB-DHS system has proven its suitability as post-treatment system for anaerobically treated tofu-processing wastewater. [ABSTRACT FROM AUTHOR]

High concentrations of suspended solids can cause water quality deterioration, leading to ecological degradation of the aquatic environment. In highly eutrophic waters, they are important carriers of pollutants and nutrients. Therefore, quantifying total suspended solids concentration ( C T S S ) is critical for any water quality monitoring program. This study proposes two band ratio algorithms for estimating C T S S in highly eutrophic lakes based on a data set of 180 in situ samples of remote-sensing reflectance, R r s λ , and C T S S measured simultaneously across 10 dates in four lakes and reservoirs in Hanoi (Vietnam). The in situ C T S S ranges from 2.7 to 73.3 mg l−1, averaging at 24.9 mg l−1, and is highly correlated to water transparency (the correlation coefficient, r = 0.73), chl-a concentration ( r = 0.78), and the trophic state index ( r = 0.89). Our analyses demonstrate the appropriateness of the near-infrared/red spectral ratio, R r s 815 / R r s 655 , model (N = 124) for estimating C T S S in the study lakes (the determination coefficient, R 2 = 0.84). The model was then verified with a small error (the root mean square error, RMSE = 4.1 mg l−1) using independent multi-date-obtained data sets (N = 56). The model is further optimized to establish a regional C T S S estimation model for Landsat 8/OLI and Sentinel 2/MSI bands using the 865 and 655 (or 665) nm bands. The band ratios showed reasonable estimations when applying to the respective spectral band ratios, i.e. the OLI's band 5/band 4 ( R 2 = 0.58; RMSE = 7.7) and the MSI band 8/band 4 ( R 2 = 0.73; RMSE = 6.1). [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effluent treatment from Nile tilapia farming in a biofloc system with a consortium of microalgae (Chlorella vulgaris) and zooplankton (Daphnia similis). Thus, integrated cultures of C. vulgaris and D. similis were performed in two forms of wastewater treatment: sedimentation (S) and non-sedimentation (NS), in four different salinities (1, 2, 3 and 4 g L−1). Water quality, growth of D. similis, behaviour of C. vulgaris, efficiency of removal of nitrogen compounds, orthophosphate, and total suspended solids (TSS) were measured. D. similis had higher density in 3NS (p < 0.05), while population die-off occurred in 4S and 4NS. The 2S and 1NS combinations stood out in bioremediation, achieving removal of up to 70.37% nitrate, 75.74% orthophosphate, and 90.74% TSS. 2S and 3S cultures became self-sufficient from day 21. Thus, the Chlorella-Daphnia consortium using 3NS allowed better production of D. similis, whereas salinities 2 g L−1 (S) and 1 g L−1 (NS) provided better bioremediation, and the use of S wastewater improved the sustainability of the system. These results contribute to a better evaluation of cultures in consortia of organisms for the treatment of aquaculture wastewater and the production of live feed for aquaculture. Four salinities and two forms of biofloc wastewater processing were evaluated. Salinity 2 and sedimentation of biofloc wastewater showed better bioremediation. Salinity 3 and non-sedimentation of biofloc wastewater had better D. similis growth. C. vulgaris could grow in biofloc wastewater even with Daphnia predation. Chlorella-Daphnia consortium is an option for bioremediation and live food production. [ABSTRACT FROM AUTHOR]

Muddy, faecally-contaminated river flood plumes in coastal waters are a hazard to contact recreation and bivalve shellfish consumption but are difficult to study, being episodic and transient. We used a new underway flow-through sampler in a small, fast boat, to map a flood plume within Wellington Harbour, while simultaneously sampling water in the Hutt River inflow. Faecal contamination (indexed by E.coli) correlated with flow, salinity, coloured dissolved organic matter, total suspended solids (TSS) and water clarity (light beam attenuation and visual clarity). The freshwater content of the plume agreed well with time-integrated river discharge. Despite the relatively short time-scale (<12 h) of the event, a 21% loss of TSS (particle flocculation and settling), and 30% loss in E. coli (suggesting some die-off) occurred in the plume compared to river loads. E. coli relative to TSS varied up to two orders of magnitude over a year of river flood sampling. A rapid survey of plumes combined with long-term river observations is expected to augment monitoring and inform the extension of remote sensing and modelling efforts to faecal contamination of New Zealand coastal waters. [ABSTRACT FROM AUTHOR]

This investigation aimed to evaluate the effects of the biofloc system on growth, digestive activity, proximate composition, and hematology of Asian stinging catfish for 120 days. Fingerlings (n = 2,700; 4.40 ± 0.10 g) were randomly distributed in six outdoor circular tanks (3,000 L) with supplementary aeration and hand-fed with a commercial diet (35% CP) at 5%–2% of the biomass in the control group and 2%–1% in the biofloc group (sugarcane molasses) to establish a (C/N) ratio 10:1. Ammonia, nitrate, nitrite, and total suspended solids were significantly lower in the BFT than in the control (P < 0.05). Suspended floc significantly ameliorates mean weight gain, percent weight gain, mean total biomass, specific growth rate, and feed utilization compared to the control (P < 0.05). Protease and amylase activity in the intestine and liver lipase activity of fish were found to be significantly higher in the biofloc group (P < 0.05). An improved hematological profile was observed in the biofloc groups (P < 0.05). The crude protein and lipid content was also higher in the biofloc system than in the control. This study indicates that biofloc would be the best alternative approach for sustainable aquaculture production of Asian singing catfish. [ABSTRACT FROM AUTHOR]

The purpose of the study was to use waste rice husk ash (RHA), residual ash generated at the rice husk fuelled clay brick kiln, for manufacturing paving blocks. Strength, durability, water quality of the paved surface run-off and microstructure of specimens were examined. Cement in paving blocks was partially replaced by five percentage of waste RHA: 0%, 5%, 10%, 15%, and 20% (by weight). At 10% waste RHA, paving block structure became denser than the conventional block, and 56-day compressive strength was improved by 18.1% and 26.5% for M15 (Grade 15) and M25 (Grade 25) blocks, respectively. Paving blocks with 10% waste RHA achieved splitting tensile strength and flexural strength greater than that of the conventional blocks. At all waste RHA levels, sulfate resistance was improved, water absorption was ranged 3–6% and British Pendulum Number was found to be higher than 45, satisfying the limits specified in standards. For the run-off, total suspended solids concentration was less than 6 mg/l, turbidity was ranged 2.15–3.57 NTU, conductivity was ranged 74.0–137.0 μs/cm and satisfied the limits in standards. This study concludes 10% of waste RHA without any pre-processing can be used as a cement replacement in paving blocks. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the degradation of methylparaben (MeP) and propylparaben (PrP) in synthetic wastewater in a membrane bioreactor (MBR) whose operation involved three stages: stage 1 (stabilization period), with no addition of parabens; stage 2, in which the MBR was fed with 0.5 mg L−1 of each paraben; and stage 3, in which both MeP and PrP were added, at 10 mg L−1each. The system performance was assessed by monitoring pH, temperature, effluent flow rate, transmembrane pressure, BOD, COD, suspended solids, and paraben concentration. The results confirmed that the MBR showed a good organic matter removal efficiency (> 92.2% for BOD; >91.6% for COD) and was not significantly affected by the addition of parabens at either low or high dosages. The volatile to total suspended solids ratio remained nearly constant, suggesting that the addition of parabens at a high concentration did not negatively impact the control of suspended solids. It was possible to achieve 96.0% of MeP and PrP removal in stage 2 ([parabens]0 = 0.5 mg L−1), and 86.0% of PrP removal in stage 3 ([PrP]0 = 10 mg L−1). Finally, biodegradation was found to be the main removal mechanism of parabens in the investigated MBR. [ABSTRACT FROM AUTHOR]

Combination of 'green' coagulation and powdered activated carbon adsorption was tested for removal of benzophenone (BP), benzophenone-3 (BP-3) and caffeine (CF) from treated municipal wastewater at realistic concentration levels (1–2 µg/L). At the same time it was tracked how the process affected effluent organic matter (EfOM) by measuring chemical oxygen demand (COD). Green coagulant was produced from dry common bean seed in laboratory. Combined coagulation-adsorption experiments were performed by applying different dosing sequences of process materials. Removal of hydrophobic BP and BP-3 by separate adsorption (from 79 to 98%) was not significantly hindered by the addition of the coagulant (activated carbon dose of 5 or 20 mg/L). However, in some cases negative effects were observed for hydrophilic caffeine, depending on the carbon dose, dosing sequence and presence of total suspended solids (TSS). Thus, when coagulant was firstly added into water without TSS before low activated carbon dose of 5 mg/L, caffeine removal dropped from 26% to 5%. Conversely, when TSS were present in the water sample, the removal of caffeine was not hindered under the same PAC dose and dosing sequence. The importance of the process optimisation related to removal of organic micropollutans of different hydrophilicity has been shown in this paper. Removal of around 30% of COD regardless of the dosing sequence was achieved. [ABSTRACT FROM AUTHOR]

Adequate wastewater management is an environmental concern because of the lack of freshwater resources, which brings about the quick augmentation of technologies for complete quantitative and qualitative wastewater recovery. In the cluster of the advanced oxidation process, hydrodynamic cavitation developed as a promising technology to treat wastewater, in the last couple of decades, due to its low-cost energy efficiency without aided and residual chemicals. In the present study, two pilot-scale experimental setups (I and II) of hydrodynamic cavitation reactor have been used to treat the secondary sedimentation tank (SST) effluent of natural six sewage treatment plant (STP) of Surat city for irrigational reuse, using an orifice as a cavitating device. At inception, the inlet pressure has been optimized, which follows the first-order kinetic rate constant. The pump power with respect to the diameter of the main pipeline has differentiated by keeping the constant dimension of the cavitating device to compare the geometrical effect and was analyzed using the number of rotations concerning recirculation time to degrade the chemical oxygen demand (COD). It is found that the maximum COD, total suspended solids (TSS), and most probable number (MPN) were degraded to 79.8%, 63.8%, and 99.5%, respectively, by setup II; also, descent within the permissible limit proclaimed by CPHEEO India to irrigate the non-edible crops. [ABSTRACT FROM AUTHOR]

This study investigated the decontamination performance of a bioretention system using a sand-based filler constructed using sand and peat soil. The filler was constructed according to a simple proportioning method that considers water turnover time and organic content. Different inorganic constituents were added to the filler including zeolite, volcanic rock, coal slag, vermiculite and perlite to further improve the decontamination effect. Total suspended solids (TSS), total phosphorus (TP), ammonium nitrogen ( NH 4 + -N), total nitrogen (TN) and chemical oxygen demand (COD) were measured in the influent and effluent. The results showed that: (1) the overall removal effect of the sand-based filler was satisfactory, indicating a certain feasibility and practicality of the method; (2) bioretention based on the sand-based filler had a better performance in removing TSS and TP with the removal rate both over 95%, and the addition of inorganic constituents to the filler was beneficial to TSS removal due to the effect of cumulative filtration capabilities of multiple materials, while phosphate was easily adsorbed by the positively charged particles of the peat soil; (3) the high removal rate of NH 4 + -N was due to adsorption and it could reach more than 80% by adding inorganic constituents with good adsorption such as zeolite vermiculite and perlite. Similarly, the addition of vermiculite and coal slag could increase the removal rate of COD by 15-25%. This research offers a novel alternative for guiding the selection and proportion of fillers in bioretention systems. [ABSTRACT FROM AUTHOR]

In recent years, petroleum and gas industries are singled out because considered to be extremely polluting. Consequently, the sustainability of this sector constitutes a challenge for oil and gas companies. As a solution to this problematic, the study suggests the use of solar energy to treat saline oily wastewater by evaporation/condensation process. It evaluates the treatment reliability and validity in term of efficiency that is also compared to a conventional treatment by coagulation/flocculation. In laboratory scale, the experiments conducted in a single treatment step obtained significant pollutants removing by reaching 98.6% of hydrocarbons, 84.3% of BOD, 78.8% of COD, 99% of total suspended solids and until 97% of metallic pollution. In real conditions of use, after one year test duration, results confirmed solar wastewater treatment (SOWAT) reproducibility of efficiency facing significant variability of pollutants concentration. Hydrocarbon ranged from 1 to 7 mg/l after a treatment of raw wastewater containing between 10.5 and 518 mg/l. Total suspended solids evolved from 1 to 200 mg/l facing a raw wastewater concentration that ranged from 100 to 880 mg/l. Comparatively to conventional treatment, SOWAT recorded close efficiency. Better yet; it stood out in its ability to remove high salinity for oil wells reinjection. [ABSTRACT FROM AUTHOR]

Glass recycling is a process that faces many obstacles, especially in the closed-loop context. Waste glass separation and transportation can become quite expensive, turning glass collection for remanufacture unfeasible. For this reason, it is important that alternative markets for waste glass are sought. This study evaluated crushed recycled glass as tertiary media in subsurface pilot-scale filters for on-site municipal wastewater treatment, using control sand media filters. Filters were operated over 128 days at a 24-h hydraulic retention time, treating secondary lagoon effluent from the rural municipality of Dunnottar, Manitoba, Canada. Crushed recycled glass filters removed 92%, 90% and 45% of the total suspended solids (TSS), ammonium nitrogen (NH4+–N) and chemical oxygen demand (COD), respectively. Total suspended solids were removed equally well in sand and crushed recycled glass filters (α = 0.05), whereas NH4+–N and COD reductions were 10% and 21% greater in sand media, respectively. Both sand and crushed recycled glass filters failed to achieve phosphorus (P) discharge guidelines. This study shows that there is potential for crushed recycled glass in wastewater filtration, especially to achieve TSS, COD and NH4+–N removal. Small communities served by waste stabilization ponds could benefit from glass media filters, as waste glass could be diverted from curbside collection and utilized locally to polish municipal lagoon effluent. [ABSTRACT FROM AUTHOR]

An integrated process of iron/carbon micro-electrolysis (ICME)–expanded granular sludge bed (EGSB)–microalgae reactor (MR) was developed for treating pharmaceutical wastewater with initial chemical oxygen demand (COD) of 25000–28500 mg/L. The results show that, under the optimum conditions, the removal ratio of COD, total suspended solids (TSS), color, NH3-N, and total phosphorus were 99.2%, 98.4%, 97.5%, 95.3%, and 78.9%, respectively. The ICME removed a considerable proportion of TSS and color, and improved the biodegradability of the wastewater, while the EGSB played an important role in the removal of residual COD, and finally, post-polish treatment was achieved in the MR. [ABSTRACT FROM AUTHOR]