Domestic Sewage Discharge Research Articles

Evaluation of Physico-Chemical Parameters to Assess Hussain Sagar and Saroor Nagar Lake Water Quality in Hyderabad, Telangana, India

Lakes are vital resources, natural surface water course also play a crucial role in groundwater recharge and they regulate the urban climate nowadays. Sewage discharge, improper agricultural practices and urban run offs have disrupted the ecosystem .In Hyderabad there are 185 lakes in that only 10 lakes have good water quality current situation due to domestic sewage and industrial waste water discharge are mixed with lake water. For our study we have selected 2 lakes, Hussain sagar, and Saroor nagar from those 175 lakes. This paper examines the present lake water quality, Four sample stations were located around two lakes totally24 samples were collected as per standard methods and, samples have been analyzed for Physico-Chemical parameters such as pH, TH, TDS, Ca2+, Mg2+,Cl-, HCO3, CO3, DO,BOD,COD. Results obtained were compared with water quality standards, irrigation standards and compared with previous study to analyzed that parameters limits.pH is observed for Hussain sagar lake are fall within the acceptable limit, for Sarooro nagar is observed are increased.TH, TDS, Ca2+, Mg2+,Cl-, HCO3, CO3 were exceeds the acceptable limits , DO,BOD and COD for 2 lakes are within the acceptable limits at present because of covid19 lockdown last year all festivals were banned.

Arthrospira sp. mediated bioremediation of gray water in ceramic membrane based photobioreactor: process optimization by response surface methodology

Direct discharge of raw domestic sewage enriched with nitrogenous and phosphorous compounds into the water bodies causes eutrophication and other environmental hazards with detrimental impacts on public and ecosystem health. The present study focuses on phycoremediation of gray water with Arthrospira sp. using an innovative hydrophobic ceramic membrane-based photobioreactor system integrated with CO2 biofixation and biodiesel production, aiming for green technology development. Surfactant and oil-rich gray water collected from the domestic kitchen was used wherein, chloride, sulfate, and surfactant concentrations were statistically optimized using response surface methodology (RSM), considering maximum microalgal growth rate as a response for the design. Ideal concentrations (mg/L) of working parameters were found to be 7.91 (sulfate), 880.49 (chloride), and 144.02 (surfactant), respectively to achieve optimum growth rate of 0.43 gdwt/L/day. Enhancement of growth rate of targeted microalgae by 150% with suitable CO2 (19.5%) supply and illumination in the photobioreactor affirms its efficient operation. Additionally, harvested microalgal biomass obtained from the process showed a biodiesel content of around 5.33% (dry weight). The microalgal treatment enabled about 96.82, 87.5, and 99.8% reductions in BOD, COD, and TOC, respectively, indicating the potential of the process in pollutant assimilation and recycling of such wastewater along with value-added product generation.

Distributed treatment of rural environmental wastewater by artificial ecological geographic information system

The existing extensive domestic sewage discharge methods and simple sewage pipe network collection modes in rural China not only cannot guarantee high sewage collection efficiency, but also fail to achieve rain and sewage diversion, resulting in the deterioration of living environment, the serious pollution of surface water and groundwater in rural areas, and even directly threatening the quality of the water environment. Therefore, accelerating the researches on rural domestic sewage treatment technologies and the scientific and effective treatment of rural domestic sewage as much as possible is a very important task at present, which is of great significance to the overall improvement of China’s rural environment. Therefore, on the basis of summarizing and analyzing previous research works, taking a town in Xuzhou City, Jiangsu Province, China as an example, this paper expounds the research status of rural domestic sewage treatment and its significance in improving rural environment, elaborates the development background, current status and future challenges of rural domestic sewage treatment technologies, introduces the related works of other scholars and the research area of this paper, analyzes the systematic mode of ecological treatment of rural domestic sewage, proposes the systematic mode of biological treatment of rural domestic sewage, conducts technological mode analysis of rural domestic sewage treatment, implements the effect evaluation of rural domestic sewage treatment, describes the impact of domestic sewage treatment on rural environment indicators, explores the improvement of the rural environment by domestic sewage treatment, discusses the applicability evaluation of different rural domestic sewage treatment technologies, and finally performs the quantitative description of the effect of domestic sewage treatment on the improvement of rural environment. The study results show that In the town of Xuzhou City, part of the mixed sewage is absorbed by the remediation plants, and part of the pollutants in the process of infiltrating the subsoil are intercepted by the soil medium, or absorbed, utilized or fixed by the roots of the remediation plants, or transformed by the microorganisms in the soil, and degraded into non-toxic or low-toxic components. The integrated technology refers to the small and medium-sized sewage treatment device developed by combining the pretreatment, secondary and advanced treatment technologies of rural domestic sewage, which is an important development direction of rural domestic sewage decentralized treatment technology. The study results in this paper provide a reference for further researches on treatment and technology of domestic sewage for improvement of rural environment in China.

Multimedia Distribution Characteristics and Risk Assessment of 22 PPCPs in the Water Environment of Qingpu District, Yangtze River Delta Demonstration Area

In this study, 50 surface water and sediment samples were collected from 25 sampling points in Qingpu District (including Taipu River basin, Jinze Reservoir, and Qingxi country park) in the Yangtze River Delta integration demonstration area, and 22 pharmaceuticals and personal care products (PPCPs) in the samples were analyzed using high-performance liquid chromatography tandem mass spectrometry (HPLC/MS-MS). The distribution characteristics, sources, and influencing factors of targeted PPCPs in the study area were studied in detail. The ecological and health risks of the target PPCPs were evaluated using the quotients method. The results showed that a total of 19 PPCPs were detected in the surface water and sediment samples from 25 sampling points in Qingpu District, with total concentrations ranging from 0.06 to 178.67 ng·L-1 and 0.07 to 37.68 ng·g-1, respectively. The average value of sulfachloropyridazine (SCP) in the surface water was the highest with a concentration of 129.54 ng·L-1, whereas the average value of sulfamethoxazole (SMX) in the sediment was the highest with a concentration of 70.62 ng·g-1. The spatial distribution of the total amount of PPCPs showed a trend of Qingxi country park > Jinze Reservoir > Taipu River basin. Principal component analysis showed that the main sources of pollution were animal antibiotics used in aquaculture and the discharge of domestic sewage. There was a significant correlation between lg Koc and lg Kd (P<0.05), indicating that the organic carbon plays an important role in the distribution of the target PPCPs in water and sediments. The ecological risk assessment results revealed that the fungicides (TCC and TCS) in the surface waters showed a moderate risk to aquatic organisms of different trophic levels. The Qingxi country park and Jinze Reservoir were the regions with the highest ecological risks of PPCPs in surface water and sediment. The health risk entropy (HQ) of people of all age groups exposed through drinking was less than 1; however, with the continuous emission and accumulation of PPCPs, the pollution control of PPCPs in the environment still requires further attention.

Exploring the Linkage between Land Use Type and Stream Water Quality of an Estuarine Island Applying GWR Model: A Case Study of Chongming, Shanghai

To understand the spatial correlations between land use type and water quality of an estuarine island is particularly essential to maintain its original ecological environment. Chongming Island is experiencing a rapid urbanization and agriculture land sprawl during the last decades, especially with the growth of agro-industry and the extension of old style residences. As a consequence, surface run-off from agricultural activities and domestic sewage discharge has a various linkage with stream water quality on the island. This study applied ageographical weight regression model approach to recognize the significance of the relationship between water quality and multiple land use. We also evaluated their spatial correlations which normally hidden from other traditional regression methods. The results reveal that the water quality of less-developed areas on Chongming Island was easily affected by land use types compared with other regions, TN, TP, BOD5, COD were shown as the most significant responses among all the water quality indicators. Green land and water area had a reduced effect on nutrients, expansion of industrial land would continuously make a contribution of pollutants to the water environment. Suggestions should therefore be taken into consideration during the process of development planning, in order to prevent water contamination.

Spatiotemporal Variation of Surface Sediment Quality in the Xiamen Sea Area, China.

The study analyzes the survey data on the surface sediments in 355 stations in Xiamen Sea area during 2004-2006, 2007-2009, 2010-2013, and 2014-2016. The result finds that contents of TOC, sulfide, and oils in the surface sediments were generally low but showed significant spatial differences (p < 0.05) in most cases, with TOC in the West Sea area (WS) staying significantly higher than other sea areas. Xiamen Sea area suffered universal heavy metal pollution mainly from Cu and Zn for years in the WS, the Jiulong River Estuary (JE), and the East Sea area (ES), and the heavy metal pollution index (HPI) exhibited significant spatial differences across the four periods (p < 0.05). With the source of heavy metals in the WS being mainly related to human activities, Cu and Zn were related to the development of port shipping and Pb to aquaculture. The heavy metal pollution in JE was mainly related to the input of rivers emptying into the sea. The high Cu content in the ES was related to the direct discharge of massive domestic sewage into the sea at the time. From 2004 to 2016, the potential ecological risks of heavy metals in Xiamen Sea area stayed low.

Pollution level, distribution characteristics and risk assessment of psychotropic substances and their metabolites in surface water of Lakes Gaoyou, Baoying and Shaobo, Jiangsu Province

为探究典型精神类药物及其代谢产物在高宝邵伯湖——宝应湖、高邮湖和邵伯湖表层水体的污染水平、分布特征及生态风险，利用超高效液相色谱-串联质谱法，对研究区域18个采样点位表层水体中3类（抗抑郁药物、抗癫痫药物和抗精神病药物）21种精神类药物及其代谢产物的浓度水平进行检测分析.结果表明，除奥卡西平外，其余20种典型精神类药物及代谢产物均有不同程度地检出，检出率范围为22.2%～100%，总检出浓度范围为1.4～224.5 ng/L.其中抗精神病药物利培酮检出浓度最高，浓度范围为0.1～64.1 ng/L.不同采样点精神类药物及其代谢产物的浓度存在空间差异，呈现邵伯湖和高邮湖南部浓度较高，高邮湖北部和宝应湖浓度较低的趋势.由聚类分析可知，点位S1、S7单独形成聚类，浓度分别为175.7和102.9 ng/L.对精神类药物及其代谢产物的来源分析发现，污水处理厂、生活污水和农业废水排放可能是高宝邵伯湖地表水中精神类药物及其代谢产物的主要来源.采用风险商值法（risk quotient，RQ）进行生态风险评估，结果表明高宝邵伯湖表层水体中卡马西平和环氧卡马西平对水生生物具有高风险（RQ>1）.精神类药物及其代谢产物在环境中持续性赋存的风险需引起重视.;To investigate the pollution level, distribution characteristic and ecological risk of psychotropic substances and their metabolites in Lakes Gaoyou, Baoying and Shaobo, Jiangsu Province, 18 water samples were collected. The concentrations of 21 psychotropic drugs and their metabolites in three classes:antidepressants, antiepileptics and antipsychotics were analyzed by ultra- high-performance liquid chromatography- triple quadrupole tandem mass spectrometry. The results indicated, in addition to oxcarbazepine, 20 typical drugs and their metabolites were detected at 18 sampling sites with the detection rates of 22.2%-100%, and the total concentration ranged from 1.4 to 224.5 ng/L. Among the detected substances, the concentration of risperidone (0.1-64.1 ng/L) was the highest. Spatial differences in the concentrations of psychotropic substances and their metabolites existed at different sampling sites, showing a trend of higher concentrations in Lake Shaobo and the southern part of Lake Gaoyou and lower concentrations in the northern part of Lakes Gaoyou and Baoying. The cluster analysis showed that point S1 and S7 formed separate clusters with concentrations of 175.7 ng/L and 102.9 ng/L, respectively. The source analysis found that wastewater treatment plants, domestic sewage and agriculture discharge may be the principal sources of the psychotropic substances and their metabolites. The risk quotient method showed that the RQ values for carbamazepine and oxcarbazepine were greater than 1 and were of high risk to aquatic organisms. The risk of psychotropic substances and their metabolites in the environment still needs attention.

Development of Blue-green infrastructure framework to restore nallahs (dirty drains) to nadis (streams), in India

The rivers and streams serve as important life support systems for helping in recharging the aquifers and regulating the hydrological cycle besides providing habitats and breading grounds for birds, fish and aquatic life. However, these are always becoming targets of adverse effects of development around the streams particularly in urban areas due to presence of human activities like urbanization and climate change. As a result of these activities, most of the urban streams have got degraded due to encroachment, siltation discharge of domestic sewage, surface drainage caring sand and silt and other chemical pollutants. Literature review is conducted to study how resilience and ecosystem services can play important role in climate change adaptation and to keep balance between nature and society. This review paper is to analyse the Green Infrastructure (GI) and the recent Blue-Green Infrastructure (BGI) are the multidisciplinary approaches to combat the negative impact of urbanization and climate change on urban streams and revive the condition totally. Identification of the need of development of Blue-Green infrastructure framework to transform nallahs (dirty drains) to nadis(Streams) in India.

Appraisal of water quality and ecological sensitivity with reference to riverfront development along the River Gomti, India

The conflict between the vitality of natural ecosystem versus artificially developed systems has existed since decades. The ecological sensitivity and socio-economic aspects associated with riverfront development along rivers have attracted the attention of environmentalists and ecologists across the globe. The present study evaluates the impacts of channelization and riverfront development on the water quality of river Gomti through Water Pollution Index (WPI) and other statistical tools. Of the total studied sites, 75% were found to be in the ‘highly polluted’ category even after the development of riverfront. An approximate increase of 274.5% and 171.76% was witnessed in the WPI values at the midstream sites of Kudiaghat and Daliganj, respectively. This increase in the WPI values clearly stated the deteriorated water quality of river Gomti after the channelization. The major issue of domestic sewage discharge with partial or no treatment into the river seems to be unresolved even after a considerable period of riverfront development. This study can provide a reference database toward development of such projects across the globe.

The Status of Abiotic Components in Aquatic Environment of Khaste Lake, Pokhara

Water is one of the most significant natural resources. In plants and animals, different physiological processes like respiration, photosynthesis, absorption of nutrients and other metabolic process get influenced by the amount of availability of water. This study has been conducted to evaluate water quality of Khaste Lake, Pokhara. After the collection of water samples, chemical parameters such as dissolved oxygen (DO), free carbon dioxide (F-CO2), hydrogen ion concentration (pH), total alkalinity (TA), total hardness (TH), total solid (TS), total dissolved solid (TDS), calcium (Ca), magnesium (Mg) and chloride ions (Cl-) have been measured in the chemistry laboratory, using standard methods prescribed by American Public Health Association (APHA, 1999) whereas the depth, transparency and temperature have been measured on the spot. The obtained values of physico-chemical parameters have been compared with the criteria of World Health Organization (WHO) and other lakes. The research reveals that all the abiotic components of the Khaste Lake meet the WHO standard of water quality. This research work concludes that the water quality of Khaste Lake is much less polluted and suitable for all the aquatic lives so far. Discharge of domestic sewage, use of fertilizers and pesticides in agriculture fields and other solid waste dumps can be the major threats for sustainability of the lakes. Awareness to the public and continual management need to be done to prevent the possibility of pollution and eutrophication process.

Occurrence, Temporal Variation (2010–2018), Distribution, and Source Appointment of Per- and Polyfluoroalkyl Substances (PFAS) in Mollusks from the Bohai Sea, China

Per- and polyfluoroalkyl substances (PFAS) including legacy and emerging compounds have been widely detected in various environmental media and have attracted a significant amount of research and regulatory attention. Aquatic environments such as seawater are important PFAS sinks due to the strong stability and water solubility of PFAS. In this study, the occurrence, temporal variation, and source appointment of 17 legacy and 16 emerging PFAS in seven different mollusks from nine cities around the Bohai Sea, China, were investigated from 2010 to 2018. Significantly higher concentrations of legacy PFAS compared to those of emerging PFAS indicate that legacy PFAS products, including perfluorooctane sulfonic acid and perfluorooctanoic acid, are still widely used in China. However, the decreasing trend of the legacy PFAS concentrations in mollusks after 2015 indicate that these products are gradually being withdrawn from the market due to China’s implementation of the Stockholm Convention. A positive matrix factorization was used to identify six primary pollution sources including electrochemical fluorination processes, domestic sewage discharge, metal plating, food packaging, the fluorochemical industry, and the fluoropolymer industry. Among these sources, the fluoropolymer industry is the largest contributor to environmental PFAS, accounting for 68% of the total pollution in this region.

Responses of Net Anthropogenic N Inputs and Export Fluxes in the Megacity of Chengdu, China

Anthropogenic N inputs have become progressively more problematic and have profoundly affected the water quality in megacities throughout China. Thus, to design and implement appropriate megalopolis watershed management, it is important to understand the relationship between N inputs and exports and to identify the N pollution sources. To that end, in this work, the net anthropogenic N inputs (NANI) in Chengdu City were estimated based on statistical data collected between 1970 and 2019. N input fluxes and pollution sources were estimated through sample collection and field measurements that were performed between 2017 and 2019, while nitrate (NO3−) was identified using stable isotope and Bayesian model (SIAR) analysis. The NANI was found to be affected primarily by livestock and poultry consumption of N rich feed. Moreover, the N export fluxes and runoff showed a high degree of correlation. Notably, NO3− fluxes exhibited a significant increase over the course of the study period, such that, by 2019, the total N fluxes (18,883.85 N kg/km2) exceeded the NANI (17,093.87 N kg/km2). The results indicate that although livestock and poultry farming were the original primary sources of NANI, their contributions declined on an annual basis. Moreover, with the emphasis placed on point source management in Chengdu City, domestic sewage discharge has been significantly reduced. Therefore, N retention in groundwater is thought to be the factor driving the N flux increase. These findings are pivotal to solving the N pollution problem in megacities like Chengdu (China).

Assessment of Spatiotemporal Variations in the Water Quality of the Han River Basin, South Korea, Using Multivariate Statistical and APCS-MLR Modeling Techniques

This study evaluated the spatiotemporal variability of water quality in the Han River Basin (HRB) as well as the contributions of potential pollution sources using multivariate statistical and absolute principal component score-multiple linear regression (APCS-MLR) modeling techniques. From 2011 to 2020, data on water quality parameters were collected from 14 sites in the Ministry of Environment’s water quality monitoring network. Using spatiotemporal cluster analysis, these sites were classified into two periods over the year (dry and wet seasons) and into three regions: low pollution region (LPR), moderate pollution region (MPR), and high pollution region (HPR). Through principal component analysis, we identified four potential factors accounting for 80.1% and 74.1% of the total variance in the LPR and MPR, respectively, and three that accounted for 72.7% of the total variance in the HPR. APCS-MLR results indicated domestic sewage and phytoplankton growth (25%), domestic sewage and seasonal influence (29%), and point pollution sources caused by domestic sewage and industrial wastewater discharge (31%) as potential factors for the LPR, MPR, and HPR. These results demonstrate that the multivariate statistical techniques and the APCS-MLR model can be effectively used to monitor network design, quantitatively evaluate potential pollution sources, and establish efficient water quality management policies.

Evaluation of eutrophication level changes in Baiyangdian Lake based on multiple biological groups

Baiyangdian Lake is the largest shallow lake in the North China Plain. Due to the increases in upstream water consumption in recent decades, the amount of natural water entering the lake has decreased, resulting in a significant drop in the water level of Baiyangdian Lake. Severe eutrophication has occurred in Baiyangdian Lake owing to the discharge of domestic sewage around the sub-lakes. With the establishment of the Xiong'an New Area in 2017, the importance of environmental governance and protection of Baiyangdian Lake has been unprecedentedly increased. The implementation of ecological water supplement from upstream reservoirs and other basins has significantly increased water level of Baiyangdian Lake. Moreover, domestic sewage from surrounding rural areas was collected. In order to understand the current state of water quality in Baiyangdian Lake, and to evaluate the effects of the previous water replenishment and pollution control projects, we investigated water physicochemical variables and aquatic organisms of Baiyangdian Lake in August 2019. We evaluated water quality status of Baiyangdian Lake based on water quality, phytoplankton, zooplankton and macrozoobenthos, by comparing with the evaluation based on the survey data in 2010. In addition, submerged macrophytes were used to evaluate the water ecological status. The results showed that the water quality state of Baiyangdian Lake in 2019 was greatly improved compared with 2010. Among them, total phosphorus concentration decreased by 88.6%, total nitrogen concentration decreased by 83.9%, chlorophyll a concentration decreased by 47.8%, and the Seechi depth increased by 43.4%. The diversity of zooplankton and macrozoobenthos were significantly increased, the density of phytoplankton was significantly reduced, the dominant species of phytoplankton changed from a general highly eutrophic type to a eutrophic type, and the distribution of the clean-type submerged macrophytes was narrowed. The evaluation methods based on submerged macrophytes species and based on zooplankton diversity were not suitable for water quality evaluation in Baiyangdian Lake. In the early stage, the pollution source of Baiyangdian Lake was concentrated in the west, which led to lower water quality. Nowadays, due to the water replenishment from the west, north and south, the hydrodynamic conditions changed significantly. In the west, pollution control projects were carried out, and the spatial distribution of water quality in Baiyangdian Lake are showing a characteristics of homogenization.

Biological Indicators for Fecal Pollution Detection and Source Tracking: A Review

Fecal pollution, commonly detected in untreated or less treated sewage, is associated with health risks (e.g., waterborne diseases and antibiotic resistance dissemination), ecological issues (e.g., release of harmful gases in fecal sludge composting, proliferative bacterial/algal growth due to high nutrient loads) and economy losses (e.g., reduced aqua farm harvesting). Therefore, the discharge of untreated domestic sewage to the environment and its agricultural reuse are growing concerns. The goals of fecal pollution detection include fecal waste source tracking and identifying the presence of pathogens, therefore assessing potential health risks. This review summarizes available biological fecal indicators focusing on host specificity, degree of association with fecal pollution, environmental persistence, and quantification methods in fecal pollution assessment. The development of practical tools is a crucial requirement for the implementation of mitigation strategies that may help confine the types of host-specific pathogens and determine the source control point, such as sourcing fecal wastes from point sources and nonpoint sources. Emerging multidisciplinary bacterial enumeration platforms are also discussed, including individual working mechanisms, applications, advantages, and limitations.

Responses of Functional Traits of Macrobenthic Communities to Human Activities in Daya Bay (A Subtropical Semi-Enclosed Bay), China

The biological trait analysis (BTA) is regarded as a promising approach to unravel how ecosystem functions respond to human-induced disturbances. This study considered the four sampling locations associated with different human activities in Daya Bay, that is, the domestic and industrial sewage discharge area (SED), mariculture area (MRC), nuclear power plants thermal discharge area (NTD), and an area with relatively low human disturbance as a reference (REF). Thirty modalities of nine traits were selected in BTA. Our results showed a clear shift in the functional structure of macrobenthic communities between the sampling locations, except for the case between NTD and REF. The trait composition in the communities did not highlight any seasonal patterns. Bioturbation, longevity, tolerance, body size, feeding habit, and environmental position were the key traits to characterize the functional structure of macrobenthic communities and demonstrated predictable responses along the environmental gradients. Water depth, DO, Chl-a, NH4+, and petroleum contaminants in sediments were the main variables influencing the trait composition. In addition, the taxonomic index (H′) and functional diversity index (Rao’s Q) showed clear differences among the sampling locations. Although there were no significant differences between NTD and REF in terms of the trait composition and functional diversity, a potential function loss in NTD still can be detected through the integrated analysis with taxonomic diversity. We suggest that the traits (except for fragility, larval development, and living habits) selected and the diversity indices (H′ and Rao’s Q) could serve as promising indicators of ecological conditions in Daya Bay.

Control System and Algorithm of Sewage Treatment Plant Based on Artificial Intelligence

With the improvement of people’s awareness of environmental protection in recent years, the related problems of water pollution treatment have gradually come into people’s view. As the source of life, water accounts for a huge proportion in our lives, but at the same time, water pollution is quietly spreading in places we don’t know. The continuous discharge of heavy industrial wastewater, agricultural wastewater and domestic sewage leads to increasingly serious water pollution. Sewage treatment(ST) is imperative, and its social benefits are huge, but the corresponding cost is high, and the return on investment is low. Traditional ST methods can not load large-scale ST. How to carry out ST based on artificial intelligence(AI), build ST plant control system, and make ST enter the era of automation is the problem to be solved. The purpose of this paper is to put forward the reform of control system for ST plant based on AI, apply AI into ST, and realize the automation and precision of ST plant. This paper mainly uses the fuzzy self-tuning PID control system algorithm, through the analysis of ST control object, analysis of fuzzy self-tuning PID controller design to complete the ST control system settings. In this paper, the literature review method and data analysis method are used. By collecting relevant data, the control system of ST plant is constructed to simulate ST, and the real-time data of ST is analyzed. The traditional PID control and fuzzy self-tuning PID control are compared. The experimental results show that the wastewater treatment plant system based on AI input, in the aspect of wastewater treatment, the concentration of COD and BOD in the treated wastewater are reduced by a certain proportion, the dissolved oxygen content in the wastewater reaches about 2.0mg/l, which meets the national discharge standard, and its rising time is reduced to 25 seconds, and the adjustment time is saved by 50 seconds.

Taxonomic diversity and metabolic activity of microbial communities in rivers and estuarine waters of Southern Baikal in summer

We analyzed the diversity of bacterial communities, metabolic activity, pH, and anthropogenic impact in the water of the estuaries and estuarine waters of the rivers in Southern Baikal in 2018 with different chemical composition. The chemical composition of waters and values of total microbial count (TMC), organotrophic bacteria (OB), and bacterial production (BP) depended on the geographical position, length of the rivers, and their water quality. In rivers with water acidification, we did not detect an effect of pH on TMC, abundance of OB, or total amount of mesophilic aerobic and facultative anaerobic microorganisms (PC). In rivers with a discharge of untreated domestic sewage, there was an increase in the content of dissolved organic carbon (DOC), concentration of nutrients, number of fecal and mesophilic bacteria, and high metabolic activity of microorganisms. The value of bacterioplankton production reached 0.26 to 12.41 per day−1; TMC – 0.155 ± 0.002 to 3.474 ± 0.044 million cells/mL. Using the massive parallel sequencing of fragments encoding the V2–V3 region of the 16S rRNA gene, we studied the diversity of bacteria and estimated the influence of chemical composition on the diversity of communities. As in other freshwater ecosystems and the pelagic zone of Lake Baikal, the members of freshwater Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, and Verrucomicrobia predominated in the estuaries and estuarine waters of the rivers. The obtained data on the number and diversity of hygiene indicator bacteria suggested fecal pollution of the rivers of Southern Baikal.

Assessment of the water and sediments quality around the coastal submarine sewage outfall in Guarujá, São Paulo, Brazil

The discharge of domestic sewage is one of the most common types of marine pollution, namely through submarine outfalls. In this study, water and sediments of the coastal submarine sewage outfall in Guarujá, São Paulo, Brazil were assessed during the high (January) and low (April) tourist seasons in 2018. The Canadian Council of Ministers of the Environmental Water Quality Index (CCMEWQI) showed a “marginal” water quality, in both seasons, where dissolved oxygen, biochemical oxygen demand, oil and greases, ammonia, surfactants, aluminium, lead, copper, nickel, Escherichia coli and Enterococci showed potential ecological risks. However, no mutagenic potential was detected in the complex mixture (Ames Salmonella/microsome test: MI&lt;2), and no protozoa and Salmonella bacteria were found. In the sediment, a total of 25 benthic taxa were inventoried, suggesting that the macrofauna is not under contamination stress. Cadmium, lead, copper, chromium, nickel and zinc were below the Threshold Effect Level, and the Geoaccumulation Index was &lt;0. Furthermore, the absence of acute toxicity to the test organism Kalliapseudes schubartii (EC50: 96h) and the Shannon-Wiener diversity index (H’: 2.5 to 3.5 bits/ind) suggests healthy or unpolluted environments. However, the deviation of some environmental indicators suggests the need of continuous monitoring based on field measurements.

Nitrogen pollution promotes changes in the niche space of fish communities.

Historically, anthropogenic fixed nitrogen has been purposely increased to benefit food production and global development. One consequence of this increase has been to raise concentrations of nitrogen in aquatic ecosystems. To evaluate whether nitrogen pollution promotes changes in the estimates of niche space of fish communities, we examined 16 sites along a Brazilian river basin highly impacted by anthropogenic activities, especially discharge of domestic and industrial sewage from a region with more than 5 million inhabitants. We analysed the carbon (δ13C) and nitrogen (δ15N) isotope ratios of fish species and both autochthonous (periphyton) and allochthonous (course and fine particulate organic matter) basal food resources. To estimate the magnitude of nitrogen pollution, we measured the nitrate and ammonium concentrations at each site. Sampling was conducted in the dry and wet seasons to evaluate the influence of seasonality. Nitrogen pollution generally increased estimates of niche space, and seasonality influenced only the niche estimates of fish communities from polluted sites. In addition, isotopic analyses of nitrogen polluted sites yielded unrealistic estimates of trophic positioning (detritivores at the top of the food web). We conclude that changes in niche space estimates reflect both alterations in baseline isotopic values and differential trophic behaviour among fishes. Our study suggests that under conditions of high pollution, other factors appear to influence isotopic estimates of niche, such as isotopically distinct sources that have not been sampled, and/or differences in δ15N turnover rates between fish tissue and basal resources, creating isotopic baselines that are challenging to interpret.