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A year-long study was conducted to assess the quantity and quality characteristics of greywater generated from different sources of an Indian household. The effect of source separation on greywater quantity and pollutant load contribution was also assessed. Composite samples were collected separately over a period of 24 h from each of the greywater source, namely hand basin, bathroom, kitchen, and laundry, and were analysed for different physico-chemical and microbiological parameters. The mean greywater generation averaged 62 L per person per day. Quantitatively, kitchen and bathroom greywater contributed 37 and 31% of the total greywater volume, respectively, while hand basin and laundry greywater accounted for 11 and 21% of the total greywater generation. Kitchen greywater contributed about 60% of the organic load in terms of biochemical oxygen demand (BOD) and chemical oxygen demand (COD), while laundry greywater was the major contributor of heavy metals and PO 4 -P loads. Hand basin and bathroom greywaters were the major sources of total coliforms. The analysis shows that separation of kitchen and laundry greywater is beneficial as it reduces pollutant load considerably.

Ding, D.-s.; Li, K.-q.; Su, Y.; Liang, S.-k.; Qu, K.-m.; Cui, Z.-g.; Zhang, P., and Wang, X.-l., 2020. Division method of pollutant discharge region and estimation of the mainland-based pollutant loads entering the Bohai Sea. In: Yang, D.F. and Wang, H. (eds.), Recent Advances in Marine Geology and Environmental Oceanography. Journal of Coastal Research, Special Issue No. 108, pp. 312–316. Coconut Creek (Florida), ISSN 0749-0208. The land-based pollutant total load control (PTLC) is an effective approach to comprehensively solve the current problem of marine pollution. The pollutant discharge region (PDR), which is the responsibility and source group, was divided for PTLC source assessment. According to the U.S. TMDLs mode, by tracing the source of the 145 points from which the land-based pollutants were discharged into the Bohai Sea, the Bohai rim was divided into two parts: the Bohai pollutant discharge band (in-band for short), whose pollutant was discharged into the Bohai Sea, and out-of-band, whose pollutant was not discharged into the Bohai Sea. The in-band area included 343 county-level administrative regions of 37 prefectural-level cities. The PDRs are further formed by the intersection of 115 watersheds, 13 sewage plants, and 17 national key monitoring sewage enterprises. These sewage enterprises discharged sewage into the sea by using an independent point, with 343 county-level administrative regions of 37 prefectural-level cities in-band. A total of 145 PDRs was combined to 42 and were further lumped together into three PDR systems. On the basis of the PDRs, the area, CODCr, nitrogen (DIN), and phosphorus (DTP) discharge flux of each PDR were estimated, which totaled 40,4476 km2, 941,072 tons, 90,570 tons, and 12,808.8 tons, respectively. The CODCr, DIN, and DTP load per one square kilometer of each PDR were estimated, which averaged 4.99, 0.42, and 0.09 tons, respectively, and varied between 0.001 and 64.068, 0.006 and 5.063, and 0.0007 and 1.672, respectively. The key PDRs were discussed. From the results, it is seen that the key PDRs mainly lie in Hebei Province along with the large rivers.

The nutrient load generated by excessive aquaculture farms leads to self-pollution around water, which destroys aqua-environment, and further leads to a decline in aquaculture production. The purpose of this study is to propose an index to assess the sustainability of inshore aquaculture in Kyushu area, considering nutrient loads from land and farms. The number and size of fish cages identified from Google satellite imagery are used to calculate annual fish production, which is then converted into annual loads of total nitrogen and total phosphorus. The pollutant load factor method is applied to calculate the land nutrient inflow. An index, including nutrient load from land and farms, bay area, water depth and distance from farms to bay, is proposed. The results show that for most of the cultured bays in Kyushu, the nutrient load from the farm is more than that from the land inflow. The bay with higher index value has a higher possibility of red tide occurrence and lower sustainability for aquaculture. Among which, location of fish farms, total nitrogen and total phosphorus loading are key factors impacting water quality within the bays.

The aim of this study is to present a method for estimating the pollutant load from different sources in an effort to provide improved information regarding water pollution and help control the surface water pollution, using Lai Chau city as a case study. The pollutant load was calculated in accordance with the Vietnam Environment Administration Decree No.154/2019 on the guidance for calculating the total pollutant load of river water. The pollutant sources include point sources (domestic wastewater, animal husbandry, industrial complexes and economic services) and surface sources (run-off from agricultural land uses) that generate wastes that potentially contaminate water bodies. The source locations were mapped and spatially joined with the drainage-basin map delineated from a Digital Elevation Model (DEM) to calculate the loads for the sub-basin units. Multivariate analysis then showed that the farming and domestic sources had the strongest positive loading factors for the sub-basins located in the city center and its fringe areas. Of these waste from animal husbandry account for up to 75.1% of total pollutant load. The main conclusion from the study’s results is that the management approach should be changed from the total controlling mode, which is currently applied in the city, to a source specific approach based on the pollutant discharge loads and the allocated capacities.

Due to unevenly distributed water resources, semi-arid regions are particularly prone to severe water shortage and quality degradation. In this study, based on long-term hydrological database (1935–2015), and the latest available water quality data sets (2011–2016), we analyzed the water crisis and its driving forces in the upper Yongding River watershed, a typical water shortage area in North China. The results showed that human induced excessive water consumption is responsible for the significantly decreased river flow over the past eight decades. Although the capacity of the watershed wastewater treatment has improved, current water quality does not meet the requirements of the national water management goals, because of the excessive nitrogen and COD Cr (chemical oxygen demand), which mainly come from the wastewater and feedlots discharge. Due to the decreased river flow, current Yongding River is unable to dilute and assimilate pollutions. The analysis of river pollutant load illustrated that more than 60 % of the nitrogen in the river water system is diverted for reservoir storage, and more than 50 % of the COD Cr and TP are diverted for irrigation, thereby, increasing the risk of reservoirs eutrophication and threatening food safety. Besides, the high Cl − (388.2 ± 322.5 mg/L) and SO 4 2− (470.6 ± 357.7 mg/L) imply that the upper river water are not suitable for drinking and irrigation purposes, and a potential risk of salinization if the river flow continues to decrease. We conclude that water resources over extraction and quality degradation are the main driving factors of the Yongding River water crisis.

A total pollutant load control system (TPLCS) was implemented in the Seto Inland Sea in 1979 to reduce the water pollution and the frequency of red tides. We estimated primary production from 1981 to 2010 to determine the effects of reducing the nutrient loadings from the surrounding land. While primary production has decreased overall in the Seto Inland Sea in response to the TPLCS and the associated reductions in the total nitrogen (T-N) and phosphorus (T-P) loads from land since 1981, the reductions were limited to 4 of its 11 subareas. Primary production has increased in the Harima Nada but has been stable in the Bingo Nada subarea, reflecting the fact that the T-N and T-P stocks have not decreased in these subareas over the study years. The inconsistent responses of the 11 subareas suggest that the characteristics of each subarea should be considered when environmental management measures are established and implemented in the Seto Inland Sea. The controls on the nutrient loadings according to the TPLCS should be modified to permit better management of this semi-enclosed sea.

Bioretention systems are of immense importance as they serve as small “sponges” for cities, cutting stormwater runoff, removing pollution, and using precipitation resources. However, performance data for these facilities are generally lacking, particularly at the field scale. This study investigated the runoff quantity regulation and pollutant removal performance of bioswale and rain garden systems from 2014 to 2017. A performance assessment of these facilities demonstrated that anti-seepage rain garden, bioswale-A, and bioswale-B effectively retained inflow volumes by the filter media, reducing runoff volumes by 54.08, 98.25, and 77.65%, respectively, on average, with only two events of overflowing. According to the water quality data in 24 rainfall events, the main pollutant indexes for the new city include total nitrogen and chemical oxygen demand, and the median values for their respective effluent event median concentrations were 1.29 and 40.13 mg/L for anti-seepage rain garden and 1.68 and 74.00 mg/L for bioswale-B systems. The mean values of pollutant removal of the three bioretention systems, except for infiltration rain garden, were 39.8–59.73% (median = 54.32%), 61.06–72.66% (median = 73.47%), and 76.67%–88.16% (median = 80.64%). Meanwhile, outflow volume of water was found to be most influenced by inflow volumes for the bioswales and anti-seepage rain garden. Mass removals were higher than concentrations owing to water volume attenuation. Based on the data of monitored pollution loads, this study estimated the annual pollutant load removal as 75.45 and 90.7% for anti-seepage rain garden and bioswale-B according to the percent of monitoring rainfall depth in total annual precipitation. This study also established the target pollutant service life model on the basis of accumulated annual load and media adsorption capacity. The results of this study will contribute to a greater understanding of the treatment performance of bioretention systems, assisting in the design, operation, and maintenance of them.

A simulation-optimization approach is a suitable tool in waste load allocation problems when considering competing objectives and complex pollutant fate and transport processes in water bodies. Here, an archived multi-objective simulated annealing (AMOSA) algorithm is developed to determine various decision variables related to multi-pollutant waste load allocation (MPWLA) problems. The developed AMOSA algorithm has been coupled to QUAL2Kw in order to derive optimal MPWLA programs in Gheshlagh River, Kordestan, Iran. Minimizing wastewater treatment plant (WWTP) costs, improving the EquityMeasure, and enhancing water quality index (WQI) of the river have been considered as objective functions of MPWLA problems. The applied WQI integrates various water quality parameters (biochemical oxygen demand (BOD), dissolved oxygen (DO), NH4-N, NO3-N, PO4-P, total suspended solids (TSS), and Coliform) in monitoring stations along the river. Results show in the scenario with the best EquityMeasure, higher pollutant removal rates have been allocated to Sanandaj WWTP effluent and pollutant point source No. 7 (creek of landfill leachate) due to their greater contributions to Gheshlagh River contamination. Owing to high pollutant load effluents and unsuitable background conditions in Gheshlagh River, more specific studies show that the water quality index may not be improved over 0.22, no matter how much cost is incurred or equity is sacrificed.

Scenario-based pollutant load analysis was conducted to develop a part of a concept for planning and management of wastewater treatment systems (WWTSs) under the mixture conditions of centralised and on-site WWTSs. Pollutant discharge indicators and pollutant removal efficiency functions were applied from another paper in the series, which were developed based on the existing conditions in urban and peri-urban areas of Bangkok, Thailand. Two scenarios were developed to describe development directions of the mixture conditions. Scenario 1 involves keeping the on-site wastewater treatment plants (WWTPs) within the areas of centralised WWTSs. Scenario 2 is dividing the centralised and on-site WWTS areas. Comparison of the smallest values of total pollutant discharge per capita (PDCtotal) between Scenarios 1 and 2 showed that the smallest PDCtotal in Scenario 1 was smaller than that in Scenario 2 for biological oxygen demand, chemical oxygen demand and total phosphorus whereas the smallest PDCtotal in Scenario 2 was smaller than that in Scenario 1 for total nitrogen, total coliforms and faecal coliforms. The results suggest that the mixture conditions could be a possible reason for smaller pollutant concentrations at centralised WWTPs. Quantitative scenario-based estimation of PDCtotal is useful and a prerequisite in planning and management of WWTSs.

The concept of pollution load indicators for planning and management of the mixture conditions of centralised and on-site wastewater treatment systems has not been discussed in detail so far. In this paper, pollutant discharge (load) indicators and pollutant removal efficiencies were quantitatively analysed to develop a part of a strategy for planning and management of municipal wastewater treatment systems (WWTSs) under the mixture conditions in Bangkok, Thailand, as a case study. Pollutant discharge indicators of on-site WWTSs were estimated based on the relevant literature. Three kinds of pollutant removal efficiency function at centralised wastewater treatment plants (CWWTPs) were empirically developed for biological oxygen demand, chemical oxygen demand, total nitrogen, total phosphorus, total coliforms and faecal coliforms based on the existing CWWTP management data. These results will be integrated into the scenario-based analysis in the second paper in the series. The results will be base datasets, and the concept and estimation methods can be applied for wastewater treatment planning and management in other areas.