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Due to climate change, desalination systems have been widely used in recent years as a suitable solution to increase freshwater resources. However, there are some environmental concerns about the disposal of brine water from desalination plants into the sea. In this article, a new probabilistic approach is developed for evaluating the environmental performance of these systems by considering the uncertainties in environmental input data. For this purpose, four levels of desalination plants based on the sizes have been defined. After modeling and performing a deterministic design for each level, the most important variables were identified by employing sensitivity analysis. Afterward, simple formulas for reliability analysis were derived using Bayesian regression to obtain the concentration and dilution of effluents. The sensitivity of these formulas to the input variables was also performed using Sobol analysis. Finally, the Probability of failure (Pf) was calculated for each level using seven reliability methods, including the well-known FORM, SORM, MCS, and four other new methods. Investigations were carried out by considering both the independence and dependence between the variables using the copula function, and the results show the importance of the dependence structure. For example, considering dependence structures based on the Gaussian bivariate copula can decrease the calculated Pf of the four defined levels by nearly 17.5, 21, 27.7, and 39.2%, respectively. The results also show the importance of considering safety factors in actual designs of outfall systems. Implementing safety factors based on an acceptable Pf is a novel approach introduced in this research to control the acceptable hours per year that excess concentration can surpass the environmental criteria. The introduced method can be applied either to design new desalination plants or to evaluate the reliability of existing plants. • A novel approach is developed to evaluate and design water outfalls based on probabilistic environmental criteria. • Variables affecting the performance of desalination outfalls were identified for small to big desalination plants. • Formulas for predicting effluent dilutions were derived using Bayesian regression with a Sobol sensitivity analysis. • Importance of considering variable correlations on the outfall performances is resulted via different reliability methods. • The introduced method is applicable to any new or existing plant and controls the times surpassing environmental criteria. [ABSTRACT FROM AUTHOR]

Adulteration is an illegal practice often committed in food and cosmetic industries, yet rarely in environmental regulation compliance. The Chinese Ministry of Ecology and Environment recently issued a law prohibiting any intentional use of 'interfering agents' during wastewater compliance testing. For the first time, such illegal practices are brought to public attention, though they have been barely discussed previously in the scientific literature. The fraudulent method involves the addition into wastewater of a sodium chlorate-based compound, named 'COD remover,' which artificially decreases the chemical oxygen demand (COD) measured during legal testing using the dichromate method. Such practices can decrease COD from 214 mg/L to below 100 mg/L. COD removers are designed to work under testing conditions, and they do not effectively purify wastewater. The use of COD removers has created an underground industry, where users can anonymously purchase those products in 25-kg packages from all major domestic online retailers in China. A notable case was recently publicized after the new legislation, where 131 tons of COD remover had been used in a municipal wastewater treatment plant. Nonetheless, very little is known about other possible cases in China and elsewhere, and whether COD is the sole target of fraudulent practice in wastewater testing. For instance, nitrites could be used as interfering agents in the iodometric method for measuring dissolved oxygen in water and wastewater. There are also reports of chemical adulteration in online monitoring of gas emissions. Since targeted chemical adulteration is based on the knowledge of reactions and mechanisms of testing methods, there is a need to develop more robust and adulteration-proof methods for wastewater testing. [ABSTRACT FROM AUTHOR]

• Effluent discharge amplifies the hyporheic exchange fluxes in the discharge area. • Higher microbiota diversity and complexity was observed in the discharge area. • Lower abundance of keystone taxa led to reduced community stability in EF area. • Keystone taxa largely determine the metabolic functions and community stability. • Controlling efficiency of keystone taxa on metabolic functions reduced in EF area. We lack a clear understanding of how anthropogenic pressures, exemplified by effluent discharge from wastewater treatment plants, destabilize microbial communities in the hyporheic zone (HZ) of receiving rivers. In this study, the spatiotemporal characteristics of hydrological parameters, and the physicochemical properties of surface and subsurface water in a representative effluent-dominated river were monitored. Sequencing of 16S rRNA amplicons and metagenomes revealed the microbial community structure in the HZ of both effluent discharge area and downstream region. The keystone taxa (taxa vital in determining the composition of each microbial cluster) and the keystone functions they controlled were subsequently identified. Effluent discharge amplified the depth of the oxic/suboxic zone and the hyporheic exchange fluxes in the effluent discharge area, which was 50-120% and 40-300% higher than in the downstream region, respectively. Microbial community structure pattern analysis demonstrated an enhancement in the rate of dispersal, an increase in microbial diversity, and an improved community network complexity in the effluent discharge area. By contrast, the number of keystone taxa in the effluent discharge area was 50-70% lower than that of the downstream region, resulting in reduced community network stability and functionality. The keystone taxa controlling metabolic functions in the networks categorized to effluent discharge area were comprised of more genera related to nitrogen and sulfur cycling, e.g., Dechloromonas, Desulfobacter, Flavobacterium, Nitrosomonas , etc., highlighting a research need in monitoring species associated with nutrient element cycling in the HZ of receiving waterbodies. The results showed that the keystone taxa could contribute positively to network stability, which was negatively correlated to hyporheic exchange fluxes and redox gradients. This study provides valuable insights that will improve our understanding of how river ecosystems respond to changes in anthropogenic pressures. [Display omitted] [ABSTRACT FROM AUTHOR]

With the intensification of human activities, fresh water resources are increasingly being exposed to contamination from effluent disposal to land. Thus, there is a greater need to identify the sources and pathways of water contamination to enable the development of better mitigation strategies. To track discharges of domestic effluent into soil and groundwater, 10 synthetic double-stranded DNA (dsDNA) 3 3 Double-stranded DNA (dsDNA); single-stranded DNA (ssDNA); base-pair (bp); bromide (Br); polymerase chain reaction (PCR); colony-forming units (cfu); relative mass recovery ( RB ); relative transport speed ( RV ); relative dispersion ( RS ); concentration breakthrough curve (BTC). tracers were developed in this study. Laboratory column experiment and field groundwater and soil lysimeter studies were carried out spiking DNA with oxidation-pond domestic effluent. The selected DNA tracers were compared with a non-reactive bromide (Br) tracer with respect to their relative mass recoveries, speeds of travel and dispersions using the method of temporal moments. In intact stony soil and gravel aquifer media, the dsDNA tracers typically showed earlier breakthrough and less dispersion than the Br tracer, and underwent mass reduction. This suggests that the dsDNA tracers were predominantly transported through the network of larger pores or preferential flow paths. Effluent tracking experiments in soil and groundwater demonstrated that the dsDNA tracers were readily detectable in effluent-contaminated soil and groundwater using quantitative polymerase chain reaction. DNA tracer spiked in the effluent at quantities of 36 μg was detected in groundwater 37 m down-gradient at a concentration 3-orders of magnitude above the detection limit. It is anticipated it could be detected at far greater distances. Our findings suggest that synthetic dsDNA tracers are promising for tracking effluent discharges in soils and groundwater but further studies are needed to investigate DNA-effluent interaction and the impact of subsurface environmental conditions on DNA attenuation. With further validation, synthetic dsDNA tracers, especially when multiple DNA tracers are used concurrently, can be an effective new tool to track effluent discharge in soils and groundwater, providing spatial estimation on the presence or absence of contamination sources and pathways. [ABSTRACT FROM AUTHOR]

The article discusses the effluent water quality in phosphate mining sites in M'Dhilla, Tunisia highlighting the suitability of water discharged in the mine for irrigation and its impact to the environment.

Municipal wastewater treatment plants (WWTPs) are frequently suspected as significant point sources or conduits of microplastics to the environment. To directly investigate these suspicions, effluent discharges from seven tertiary plants and one secondary plant in Southern California were studied. The study also looked at influent loads, particle size/type, conveyance, and removal at these wastewater treatment facilities. Over 0.189 million liters of effluent at each of the seven tertiary plants were filtered using an assembled stack of sieves with mesh sizes between 400 and 45 μm. Additionally, the surface of 28.4 million liters of final effluent at three tertiary plants was skimmed using a 125 μm filtering assembly. The results suggest that tertiary effluent is not a significant source of microplastics and that these plastic pollutants are effectively removed during the skimming and settling treatment processes. However, at a downstream secondary plant, an average of one micro-particle in every 1.14 thousand liters of final effluent was counted. The majority of microplastics identified in this study had a profile (color, shape, and size) similar to the blue polyethylene particles present in toothpaste formulations. Existing treatment processes were determined to be very effective for removal of microplastic contaminants entering typical municipal WWTPs. [ABSTRACT FROM AUTHOR]

The release into the environment of antimicrobial compounds from both human and agricultural sources is a growing global concern. The Grand River watershed, the largest mixed-use watershed in southern Ontario, receives runoff from intensive animal production as well as municipal wastewater effluents from a rapidly increasing human population. A survey of surface waters and wastewater effluents was conducted across the watershed to assess the occurrence and distribution of several antimicrobials (i.e., trimethoprim, sulfamethoxazole, sulfamethazine, lincomycin, and monensin) and chemical indicators (i.e., ammonia, nitrate, ibuprofen, venlafaxine, atrazine) and to characterize exposure levels. The human antimicrobials trimethoprim and sulfamethoxazole were detected in the urban areas of the main channel at mean concentrations of 8 ± 7 ng/L and 31 ± 24 ng/L, respectively, but at much lower concentrations in the agricultural tributaries. In contrast, the veterinary antimicrobial sulfamethazine was detected at a mean concentration of 11 ± 9 ng/L in the main channel, and at a much higher concentration in the agricultural tributaries. Lincomycin was detected in only two river samples and not in the effluents while monensin was not detected in all samples. The herbicide atrazine was detected at very low concentrations in the surface waters of both the tributaries and the main channel. The concentrations of the antimicrobials and chemical indicators generally increased downstream of the confluences with agricultural tributaries and effluent outfalls. In the wastewater effluents, the concentrations of trimethoprim, sulfamethoxazole, ibuprofen, and venlafaxine decreased with increasing treatment levels (i.e., secondary to tertiary) as indicated by ammonia/nitrate concentrations. There was a strong correlation among trimethoprim, sulfamethoxazole, and venlafaxine in the main channel and in the wastewater effluents. While the environmental concentrations of antimicrobials in the watershed are low relative to toxicity thresholds, their persistence in the environment may be an important consideration in defining strategies for future water management. [ABSTRACT FROM AUTHOR]

Designing and building a treatment facility is complex. To succeed, engineers and operators must break down barriers and collaborate during design, construction, and the initial years of facility operations. An operator typically understands the space, mechanical requirements, and actions required for day-to-day work, and can help the engineering design team account for practical considerations. Many older treatment facilities feel stuck at their current location. They also are often limited in their ability to implement upgrades based on the footprint of the existing facilities. However, based on dialog with the city of Ellsworth, Maine, planners, operators, and engineers were able to think outside the box and develop a plan to design and build a new facility at a new off-site location that was both economical and state-of-the-art. Building a new wastewater treatment facility (WWTF) at a new location has allowed the city to address the lack of adequate sanitary wastewater infrastructure that challenged goals for expansion of the local economy. This and the cost-saving features of the new WWTF demonstrate the value of the city's decision to invest in a new facility and provide sustainable utility service. [ABSTRACT FROM AUTHOR]

The 454 pyrosequencing technique was applied to evaluate microbial community composition in sediment and water samples collected from the river receiving effluents from a swine farm and a farmhouse restaurant, respectively. For each sample, 4,600 effective sequences were selected and used to do the bacterial diversity and abundance analysis, respectively. Bacterial phylotype richness in the river sediment sample without effluent input was higher than the other samples, and the river water sample with addition of effluent from the swine farm had the least richness. Effluents from both the swine farm and the farmhouse restaurant have the potential to decrease the bacterial diversity and abundance in the river sediment and water, especially it is more significant in the river sediment. Effect of effluent from the swine farm on riverine bacterial communities was more significant than that from the farmhouse restaurant. Characterization of bacterial community composition in sediments from two tributaries of the downstream river showed that various effluents from the swine farm and the farmhouse restaurant have the similar potential to reduce the natural variability in riverine ecosystems, and contribute to the biotic homogenization in the river sediment. [ABSTRACT FROM AUTHOR]

Abstract: Contaminants released from wastewater treatment plants can persist in surface waters for substantial distances. Much research has gone into evaluating the fate and transport of these contaminants, but this work has often assumed constant flow from wastewater treatment plants. However, effluent discharge commonly varies widely over a 24-hour period, and this variation controls contaminant loading and can profoundly influence interpretations of environmental data. We show that methodologies relying on the normalization of downstream data to conservative elements can give spurious results, and should not be used unless it can be verified that the same parcel of water was sampled. Lagrangian sampling, which in theory samples the same water parcel as it moves downstream (the Lagrangian parcel), links hydrologic and chemical transformation processes so that the in-stream fate of wastewater contaminants can be quantitatively evaluated. However, precise Lagrangian sampling is difficult, and small deviations – such as missing the Lagrangian parcel by less than 1h – can cause large differences in measured concentrations of all dissolved compounds at downstream sites, leading to erroneous conclusions regarding in-stream processes controlling the fate and transport of wastewater contaminants. Therefore, we have developed a method termed “verified Lagrangian” sampling, which can be used to determine if the Lagrangian parcel was actually sampled, and if it was not, a means for correcting the data to reflect the concentrations which would have been obtained had the Lagrangian parcel been sampled. To apply the method, it is necessary to have concentration data for a number of conservative constituents from the upstream, effluent, and downstream sites, along with upstream and effluent concentrations that are constant over the short-term (typically 2–4h). These corrections can subsequently be applied to all data, including non-conservative constituents. Finally, we show how data from other studies can be corrected. [Copyright &y& Elsevier]

Since the introduction of the water footprint concept in 2002, in the context of humankind's ever-increasing awareness of the valuable global freshwater resources, it has received more and more attention. The application of this relatively new concept has been expected to provide ecological and environmental benefits. For the water-intensive papermaking industry, it seems that water footprint needs to be addressed. The water footprint of cellulosic paper can be divided into three components, including its green water footprint, blue water footprint, and grey water footprint, which may be accounted for by considering the individual contributions of wood or non-wood materials, pulp production processes, effluent discharge to the receiving water bodies, process chemicals and additives, energy consumption, etc. In the literature, the accounting of water footprint during the whole production chain of cellulosic paper is already available, and relevant research findings can provide useful insights into the application of the concept; however, further development of the accounting methodologies is much needed, so that the quantitative and qualitative evaluation of water footprint can be internationally recognized, certified, and standardized. Although there are ongoing or upcoming debates and challenges associated with the concept, its application to papermaking industry may be expected to provide various encouraging possibilities and impacts. [ABSTRACT FROM AUTHOR]

Water quality assessment is a key factor in the environmental management of freshwater networks, especially those including fish farms, which need cost-effective operational tools to monitor and control their waste output. In France, current legislation specifies limits in concentrations of dissolved compounds and suspended solids at fish-farm outlets. Despite the development of mass-balance modelling tools, chemical analysis of water (hydrological method) remains the most widely used method. To understand better the environmental impact of trout farms on aquatic ecosystems and to compare waste assessment methods, we monitored 20 commercial flow-through trout farms for 24 h, and we compared data obtained with the two methods (hydrological method and mass balance modelling) by linear regression. For total nitrogen and total phosphorus, the correlation between the two methods was high; thus, considering the uncertainty of both methods, this study was not able to determine which was more accurate. The high correlation between observed ammonia concentrations and predicted total nitrogen emissions provides a coefficient for estimating ammonia emissions at the farm level. The same approach is proposed for the evaluation of phosphate emissions. In conclusion, this study confirms the utility of simulation modelling for assessing nutrient release from fish farms. [ABSTRACT FROM PUBLISHER]

In this study an attempt is made to estimate nitrogen and phosphorus discharged to the environment from the striped catfish (Pangasianodon hypophthalmus) farming sector in the Mekong Delta (8°33′-10°55′N, 104°30′- 106°50′E), South Vietnam. The sector accounted for 687,000 t production in 2007 and 1,094,879 t in 2008, with over 95% of the produce destined for export to over 100 countries. Commercial and farm-made feeds are used in catfish farming, currently the former being more predominant. Nitrogen discharge levels were similar for commercial feeds (median 46.0 kg/t fish) and farm-made feeds (median 46.8 kg/t fish); whilst, phosphorus discharge levels for commercial feeds (median 14.4 kg/t fish)were considerably lower than for farm made feeds (median 18.4 kg/t fish). Based on the median nutrient discharge levels for commercial feeds, striped catfish production in the Mekong Delta discharged 31,602 t N and 9,893 t P, and 50,364 t N and 15,766 t P in 2007 and 2008, respectively. However, the amount of nutrients returned directly to the Mekong River may be substantially less than this as a significant proportion of the water used for catfish farming as well as the sludge is diverted to other agricultural farming systems. Striped catfish farming in the Mekong Delta compared favourably with other cultured species, irrespective of the type of feed used,when the total amounts of N and P discharged in the production of a tonne of production was estimated. [ABSTRACT FROM AUTHOR]

Abstract: Antibiotic transport downstream from a wastewater treatment plant effluent discharge was evaluated along stream reaches on Mud Creek, Spring Creek, and Decatur Branch in northwestern Arkansas, USA. Water and streambed samples were collected during August and September 2006 and analyzed for multiple antibiotics representing five classes (beta-lactams, macrolides, quinolones, sulfonamides, and tetracyclines). Antibiotics within the classes macrolides, quinolones, and sulfonamides were detected in the water column at all three stream reaches. Several of these same antibiotics, as well as antibiotics from the class tetracycline, were measured in streambed material at quantities significantly greater than those observed in the water column. Pseudo-partitioning coefficients ranged from 4 to >8000Lkg−1. Most of the antibiotics studied were significantly retained in the reaches at Mud Creek and Spring Creek and traveled kilometer-scale distances (S net, 3.3–20.2km) with low uptake velocities (, 2.9–16.1×10−6 ms−1) and rates (U net 0.01–37.9×10−6 μgm−2 s−1). Some antibiotics increased in concentration downstream from the effluent discharge at Decatur Branch, suggesting possible release from within the fluvial channel or additional sources along the stream reach. In general, antibiotics traveled kilometer-scale distances before significant dilution occurred through in-stream processes (e.g., advection, dispersion, sorption, uptake and/or degradation) within the fluvial channel of these effluent-dominated streams. [Copyright &y& Elsevier]

Abstract: Umm Al Nar Power and Desalination Plant is one of the largest plants in Abu Dhabi Emirate, United Arab Emirates. The plant was built in the mid eighties and its capacity was increased in 2001. The present plant capacity after the extension is 1000 Mega Watt power and 165 Million Gallon water per day. Recently, it was decided to develop and reclaim the Raha Beach coastal area near the plant for housing and recreation purposes. This requires reclamation of a large area in the Airport Channel, which is a large channel connected to the plant vicinity. A comprehensive study was carried out by Water & Power Research Center of Abu Dhabi Water & Electricity Authority to investigate the impact of the reclamation activities in the Airport Channel on the flow pattern in the plant vicinity and the recirculation of effluents from the outfalls of the plant to its intakes. The paper describes the two-dimensional numerical hydrodynamic flow model used in the study. The model results showing the effects of the reclamation activities on the flow pattern and the brine disposal of the plant is presented and discussed. [Copyright &y& Elsevier]

Abstract: Phosphorus (P) loads from point sources have a significant influence on dissolved P concentrations in streams and sediment-water column dynamics. The goal of this study was to quantify dissolved P concentrations and sediment-P interactions in Ozark (USA) headwater streams with high point source P loads. Specifically, the objectives were to: (1) compare soluble reactive P (SRP) upstream and downstream from wastewater treatment plant (WWTP) effluent discharges; (2) examine longitudinal gradients in SRP downstream from WWTPs; (3) evaluate the effect of WTTP P inputs on sediment-water column P equilibrium and sediment exchangeable P. Water and sediment samples were collected, extracted and analyzed from July 2002 through June 2003 at these Ozark streams. Mean SRP concentrations in the select Ozark streams were significantly greater downstream from effluent discharges (0.08–2.10mgL−1) compared to upstream (0.02–0.12mgL−1). Effluent discharge from the WWTPs increased equilibrium concentrations between stream sediments and the water column; mean sediment equilibrium P concentration (EPC0) was between 0.01–0.07mgL−1 upstream from WWTP and the increase downstream was proportional to that observed in water column SRP. Sediment exchangeable P (EXP) was greater downstream from the effluent discharges (0.3–6.8mgkg−1) compared to upstream (0.03–1.4mgkg−1), representing a substantial transient storage of P inputs from WWTPs. Furthermore, P was generally not retained in these stream reaches when dilution was considered using a hydrologic tracer and was released in one stream reach where effluent P concentrations decreased over the study period. Thus, the effect of the WWTPs was profound in these streams increasing water column and sediment-bound P, and also reducing the ability of these stream reaches to retain P. In P-enriched streams, effluent P discharges likely regulate sediment and aqueous phase P equilibrium and sediment bioavailable P, not the sediments. [Copyright &y& Elsevier]

Mangrove soils with high organic carbon (C org) content are likely to contain C org that is vulnerable to remineralization during land use changes. Mangrove conversion to different land uses might deplete soil C org stocks causing variable carbon dioxide emissions, but the extent of these emissions and the fraction of soil C org (i.e., labile or stable/recalcitrant) that is mostly lost is poorly understood. Here, we study mangrove soil C org degradability and its susceptibility to mineralization after mangrove disturbance. We measured changes in soil properties, organic matter (OM) stability and C org pools and sources across a mangrove disturbance gradient (i.e., pristine forests, degraded mangroves receiving domestic sewage and shrimp farm effluents, and shrimp ponds). Results showed that the conversion of mangroves to shrimp ponds caused the most severe changes in soil properties, OM and C org characteristics. Shrimp pond soils contained the lowest OM-C org pools, consisted mostly of stable OM (i.e., recalcitrant and refractory; 36.0 ± 5.7% of the total OM) and enriched δ13C org (−22.6 ± 2.7‰). Conversely, control mangrove soils had the largest OM-C org pools consisting of a large unstable OM fraction (i.e., labile; 46.4 ± 4.2%) and lighter δ13C org (−26.8 ± 0.4‰) being characteristic of C org from a mangrove origin. Conversion of mangroves to shrimp ponds and its degradation by shrimp farm and domestic sewage effluents caused a loss of 97%, 61%, and 35% of soil C org stocks in the upper meter, representing potential emissions of ~1200, 800, and 400 Mg CO 2 ha−1, respectively. These losses were explained by enhanced OM mineralization of unstable fractions driven by the loss of the physico-chemical protection provided by fine-grained soils and vegetation cover. The differences in C org stability among sites can be used to predict potential carbon dioxide produced during mineralization, hence aid at prioritizing areas for conservation, restoration or management. [Display omitted] • Human impacts change the amount, source and stability of soil OM in mangroves. • The ratio of soil unstable/stable OM decreased across a disturbance gradient. • Loss of fine sediments and nutrient inputs stimulated soil OM mineralization. • C stocks in impacted soils are between ~30 to 97 % lower than in pristine soils. • Anthropogenic impacts alter the ability of mangrove soils to store C. [ABSTRACT FROM AUTHOR]

To circumvent wastewater concern of textile industry and cost-effectively utilize waste cooking oil, this study replaced water with waste cooking oil (WCO) in reactive dyeing, and enabled circulated utilization of WCO without jeopardizing dyeing quality, as well as value addition to WCO industry. Current textile dyeing process discharges tremendous amount of wastewater comprised of high concentrations of salts and hydrolyzed dyes. However, none of the existing remediation methods, such as optimization of dyeing processes, chemical modifications of fibers and post-dyeing treatments, showed effectiveness or efficiency. In a dual-phase reactive dyeing, oil and water were used to disperse dye particles and swell cotton fibers. Dyes could be quickly dissolved in water phase and adsorbed into cotton fibers from the interface of water and oil. Though non-edible WCO could be used as a medium for salt-free reactive dyeing, WCO degraded during dyeing and showed gradually deteriorated dyeing quality if repeatedly used. For the first time, this work quantified influence of glycerol and sodium fatty acid, two main WCO hydrolysates, on dyeing results, and revealed the influencing mechanism. As a solution, alkaline refinement was applied after each dyeing cycle to revive functionality of the WCO medium, and could effectively enable WCO reusable in reactive dyeing. Effluent from conventional reactive dyeing could contain up to 100 g/L electrolytes and 50% of initially added dyes, while effluent from WCO reactive dyeing contained no electrolytes and minimal amount of dyes, and could be discharged after simple treatment. Regarding value addition to WCO, textile route might also be economically favorable than biodiesel route. Overall, the WCO reactive dyeing system could have good industrialization potential as a cleaner textile wet process. Image 1 • Waste cooking oil (WCO) was used for cotton dyeing with constantly good quality. • Circulated dyeing of cotton could be realized with minimal waste discharge. • Application of WCO in cotton dyeing had high industrialization potential. • Effluent of WCO dyeing met highest discharge standard with simple treatment. [ABSTRACT FROM AUTHOR]

Wastewater discharge is considered to be a significant point source of microplastic (MPs) release into the marine environment. This study is the first attempt to quantify MPs released from the wastewater outfall from Bandar Abbas City into the Persian Gulf. Two wastewater discharge stations at Gursuzan and Suru were sampled. MPs were isolated by an oxidative procedure and subsequent density separation using ZnCl 2 solution. The average MP concentration in wastewater and sludge were 70.66 (±14.12, SD) MP.35 L−1 and 6070 (±807.25) MPs.kg−1, respectively at Confidence Level (CL) (95.0%). The most commonly recovered polymers were polyethylene (PE) and polypropylene (PP) in all size classes. Our findings provides a baseline of MP concentration in wastewater streams and slurry that is discharged from the Bandar Abbas wastewater treatment facility into the Persian Gulf. This highlights the need to undertake more studies at water treatment plants in the region for a realistic assessment of MP discharge into the Persian Gulf. • First data of MPs from a wastewater treatment plant in the Persian Gulf. • An average of 1.2 × 10 8 MPs day−1 could be released into the Persian Gulf from Bandar Abbas city. • Shape dominance of MPs in effluent and sludge were fiber > film > fragment > granule. • Polyethylene (PE) and polypropylene (PP) were dominant polymers. [ABSTRACT FROM AUTHOR]

Microplastics (MPs, <5 mm in size) are classified as emerging contaminants but treatment processes are not designed to remove these small particles. Wastewater treatment systems have been proposed as pathways for MPs pollution to receiving waters but quantitative and qualitative data on MP occurrence and transport remains limited, hindering risk assessment and regulation. Here, for the first time, the stepwise abundance and loading of MPs (60–2800 μm) in a tertiary wastewater treatment plant in the UK was assessed by sampling from May 2017 to February 2018. Microplastics were found in all sampling campaigns, with an average inflow of 8.1 × 108 (95% CI, 3.8 × 108 to 1.2 × 109) items day−1. Their prevalence decreased from influent to final effluent. Overall abundances decreased on average by 6%, 68%, 92%, and 96% after the pre-treatment, primary, secondary, and tertiary treatment stages respectively, although considerable variability occurred throughout the year. Sufficient particles remained in the treated effluent to generate an average discharge of 2.2 × 107 (95% CI, 1.2 × 107 to 3.2 × 107]) particles day−1 to the recipient river. Secondary MPs were predominant, while primary MP abundances were minimal. Fibres comprised 67% of all items, followed by films (18%) and fragments (15%). Chemical characterisation confirmed the presence of different types of polymers, with polypropylene fibres and fragments most abundant (23%). This research informs understanding of how wastewater effluent may channel MPs to the natural environment and their composition, and helps understand control points for optimising advanced treatment processes. Image 1 • Average inflow rate of microplastics in wastewater was 8.1 × 108 particles day−1. • Fibres were the most abundant type of microplastic. • FTIR-ATR analysis revealed polypropylene was the most abundant synthetic polymer. • Tertiary treatment appears to remove 97% of influent microplastics. • More than 1.2 × 107 particles day−1 may be discharged from the WWTP. [ABSTRACT FROM AUTHOR]

The main focus of this study is on the near-field flow and mixing characteristics of the thermal and saline wall jets. A numerical study of the buoyant wall jets discharged from submerged outfalls (e.g., from desalination plants) has been conducted. The performance of different Reynolds-averaged Navier-Stokes (RANS) turbulence models has been investigated and various , , and other turbulence models have been studied. The results of cling length, plume trajectory, temperature dilutions, and temperature and velocity profiles are compared to both available experimental and numerical data. It was found that two models perform best among the seven models chosen in this paper. According to the results from different simulations, the paper proposes corresponding relationships and comparative graphs that are helpful for a better understanding of buoyant wall jets. [ABSTRACT FROM AUTHOR]

Water authorities apply a diversity of models and input data to set water quality-based emission limits in discharge permits. To illustrate the consequences of model and data selection, two complete mixing models and four mixing zone models used in Germany, the United Kingdom (UK), the Netherlands and the United States of America (USA) were selected and applied to various discharges of cadmium. The maximum allowable annual cadmium load was calculated for each model and diverging input data for upstream flow, upstream concentration, effluent flowand effluent concentration. Due to model selection, differences in pollutant loads amounted to a factor 3. Harmonization of the derivation of water quality-based emission limits is necessary to prevent widely divergent pollutant loads under comparable environmental conditions. [ABSTRACT FROM AUTHOR]

Routine environmental effects monitoring (EEM) should include field bioassays with caged bivalves -- chemical exposure is characterized by measuring the concentration of chemicals in tissues and biological effects are characterized by measuring growth. This field bioassay combines the experimental control of laboratory bioassays with the environmental realism of field monitoring. Transplanting caged bivalves in the immediate vicinity of discharges ensures maximum exposure; if bioavailable chemicals are present in the effluent they will be accumulated within the tissues, and if the concentrations are sufficiently high to be deleterious, the effect of the exposure can be quantified.The transplant methodology described herein can be used to identify the following: (1) site-specific differences; (2) short-term and long-term trends; (3) temporal and spatial variability; (4) source identification; and (5) exposure--dose-response relationships. These results will help answer one of the most commonly asked questions asked by industry, government, and the public: "Are conditions getting better,worse, or staying the same?" Further, using the bivalve transplant approach as part of an integrated program will help reduce uncertainties associated with more traditional approaches like fish monitoring, laboratory bioassays and benthic community assessments. [ABSTRACT FROM AUTHOR]

The importance of salinity in whole effluent toxicity tests using marine organisms has been acknowledged in most testing protocols. However, little if any attention has been given to the specific effects ofalteration of the ionic composition of seawater solutions to the test organism. The presence of persistent toxicity in effluents with no apparent toxic agents prompted examination of the potential influenceof essential ions on the survival of the opossum shrimp, Mysidopsis bahia, a common effluent toxicity indicator organism. Through stepwise additions of ionic salts to deionized water, the minimum complementof salts to maintain survival of M. bahia during 96-h exposures was determined to be Ca, Mg, K, Br, Na, and Cl. The toxicity curves for Ca, Mg, K, and Br were then determined across test salinity ranging from 10 to 35 parts per thousand. These curves for Ca, Mg, and K revealed that there are significant negative effects on survival when the essential ions are present in either low or high concentrations relative to the levels in natural seawater. Although there were no statistically detectable effects of Br on organism survival over the concentration range tested (5--480 mg/L), Br toxicity at concentrations less than 5 mg/L and greater than 700 mg/L have been shown in other studies. In addition, the tolerance ranges for K, Ca, and Mg were shown to shift significantly with changes in salinity, with lower salinity causing an apparent decrease in tolerance to an excess of essential ions. Tests with toxic effluents from five industrial and municipal sources revealed that adjustment of the ionic balance prior to testing reduced or eliminated toxicity in four of the five whole effluents tested. Suggestions for integrating this information into biomonitoring programs and toxicity identification evaluations are presented. [ABSTRACT FROM AUTHOR]