Urban Non-point Pollution Research Articles

Spatiotemporal Variation in Groundwater Quality and Source Apportionment along the Ye River of North China Using the PMF Model.

Groundwater quality deterioration has attracted widespread concern in China. In this research, the water quality index (WQI) and a positive matrix factorization (PMF) model were used to assess groundwater quality and identify pollution sources in the Ye River area of northern China. Research found that TH, SO42−, and NO3− were the main groundwater pollution factors in the Ye River area, since their exceeding standard rates were 78.13, 34.38, and 59.38%, respectively. The main groundwater hydrochemical type has changed from HCO3-Ca(Mg) to HCO3·SO4-Ca(Mg). These data indicated that the groundwater quality was affected by anthropogenic activities. Spatial variation in groundwater quality was mainly influenced by land use, whereas temporal variation was mainly controlled by rainfall. The WQI indicated that the groundwater quality was better in the flood season than in the dry season due to the diluting effect of rainfall runoff. Notably, farmland groundwater quality was relatively poor as it was affected by various pollution sources. Based on the PMF model, the main groundwater pollution sources were domestic sewage (52.4%), industrial wastewater (24.1%), and enhanced water–rock interaction induced by intensely exploited groundwater (23.6%) in the dry season, while in the flood season they were domestic sewage and water–rock interaction (49.6%), agriculture nonpoint pollution (26.1%), and industrial wastewater and urban nonpoint pollution (23.9%). In addition, the mean contribution of domestic sewage and industrial sewage to sampling sites in the dry season (1489 and 322.5 mg/L, respectively) were higher than that in the flood season (1158 and 273.6 mg/L, respectively). To sum up, the point sources (domestic sewage and industrial wastewater) remain the most important groundwater pollution sources in this region. Therefore, the local government should enhance the sewage treatment infrastructure and exert management of fertilization strategies to increase the fertilizer utilization rate and prevent further groundwater quality deterioration.

Prediction of Urban Non-point Pollution Load by Statistical Analysis of Data of Published Research and Its Reliability Evaluation –Statistical Analysis of Mean Load and Verification and Modification of Previously Proposed Model Using Newly Obtained Data–

Prediction of Urban Non-point Pollution Load by Statistical Analysis of Data of Published Research and Its Reliability Evaluation –Statistical Analysis of Mean Load and Verification and Modification of Previously Proposed Model Using Newly Obtained Data–

Spatiotemporal Patterns in River Water Quality and Pollution Source Apportionment in the Arid Beichuan River Basin of Northwestern China Using Positive Matrix Factorization Receptor Modeling Techniques.

Deteriorating surface water quality has become an important environmental problem in China. In this study, river water quality was monitored in July (wet season) and October (dry season) 2019 at 26 sites, and a water quality index (WQI) and positive matrix factorization (PMF) model were used to assess surface water quality and identify pollution sources in the Beichuan River basin, Qinghai Province, China. The results showed that 53.85% and 76.92% of TN, 11.54% and 34.62% of TP, 65.38% and 76.92% of Fe, and 11.54% and 15.38% of Mn samples in the dry and wet seasons, respectively, exceeded the Chinese Government’s Grade III standards for surface water quality. The spatial variation in water quality showed that it gradually deteriorated from upstream to downstream as a result of human activity. The temporal variation showed that water quality was poorer in the wet season than in the dry season because of the rainfall runoff effect. The PMF model outputs showed that the primary sources of pollution in the wet season were mineral weathering and organic pollution sources, domestic and industrial sewage, and agricultural and urban non-point pollution sources. However, in the dry season, the primary sources were mineral weathering and organic pollution sources, industrial sewage, and domestic sewage. Our results suggest that the point pollution sources (domestic and industrial sewage) should be more strictly controlled, as a priority, in order to prevent the continued deterioration in water quality.

Effect of intermittent operation model on the function of soil infiltration system.

To enhance denitrification in a process of solute infiltration through a soil, a two-section mixed-medium soil infiltration system (TMSIS) for urban non-point pollution was developed. The artificial aerobic respiration and nitrification took place in the upper aerobic section (AES), while grass powders and sawdust were mixed in the bottom anaerobic section (ANS) to supply organic carbon source for denitrification bacteria, and the reduction was increased by iron addition in the ANS. Measured resident concentrations from the bottom of each ANS column were assumed to represent mean values averaged over the column cross-sectional area. The TMSIS with hydraulic loading rates (HLR) of 0.32, 0.24, and 0.16m3m-2day-1 and with wetting-drying ratio (RWD) of 1.0 showed remarkable removal efficiencies for chemical oxygen demand (COD), NH4+-N, and TP, respectively. The hydraulic loading rate of 0.32m3m-2day-1 was selected as the optimal HLR due to the high contaminated runoff treatment efficiency. When RWD was 1.0, 0.5, or 0.2 with hydraulic loading rate of 0.32m3m-2day-1, the TMSIS could treat synthetic urban runoff contaminants very well. The corresponding effluent water met the China's national quality standard for class V surface water. The wetting-drying ratio of 0.5 with hydraulic loading of 0.32m3m-2day-1 was selected as the optimal operation conditions for the TMSIS. Aerobic respiration and nitrification mainly took place in the upper AES, in which most of the COD and the NH4+-N were removed. Mixed sawdust and grass powders used as a carbon source and heterotrophic denitrification were put at the bottom of the ANS. The developed TMSIS has the potential to be applied for urban non-point pollution removal.

The Effect of Different Artificial Soil on Urban Non-Point Source Pollution Reduction in the Artificial Rapid Infiltration System

The non-point source pollution posed great risks to the urban water environment which has aroused great concerns. Artificial rapid infiltration systems have been widely used in sewage treatment, which have great environmental and economic values. This study investigated the potential of utilizing artificial rapid infiltration systems on the reduction of urban non-point source pollution. The obtained results showed that the components and composition of artificial soils were vital to the operational performance. The mixture of natural soil, coarse sand and zeolite was ideal for the construction of artificial soils. The permeability coefficient of soils could be improved to 0.166 cm/min at the optimized ratio of 1:1:0.05 (natural soil, coarse sand and zeolite). Also, high removal efficiency for the typical pollutants in rain runoffs (i.e. COD, NH4+-N, TN and TP) could be simultaneous obtained which was above 74% in the artificial rapid infiltration systems. The results demonstrated the effectiveness on the reduction of urban non-point pollution by optimized artificial rapid infiltration system.

Coupling natural and human processes to simulate changes in the water environment in the Dianchi Lake basin, China

This study proposes a comprehensive simulation model that couples natural and human processes that have traditionally been simulated and analyzed independently. This model was established to support a risk assessment associated with natural disasters and social emergencies. In this paper, a driving mechanism was refined to reflect changes in the water environment and to understand the natural process of non-point source pollution formation in the Dianchi Lake basin. The land use and land cover model, incorporating the changes from the human activities and the natural process, was constructed to understand how humans affect the land use and land cover in the Dianchi Lake basin. Moreover, this paper studies the effects of land use and land cover changes on the non-point pollution and the urban non-point pollution with the SWAT and SWMM models. The land use and land cover changes, especially the growth and spread of the urban area, are changing the structure of the ecosystem and are degenerating the functions of the ecosystem. Ultimately, this study comprehensively simulated natural and human processes to analyze the effects of the human activities on water environment.

公表調査データの統計解析による市街地ノンポイント汚濁負荷流出量の予測とその信頼性評価

雨天時における市街地流出を調査している報告書, 論文等の文献を収集し (1968～2011年) , 一降雨を単位とした市街地の汚濁負荷 (BOD, COD, SS, TN, TP) の負荷流出データベース (DB) をまとめ, 一降雨の流量加重平均濃度 (EMC) の分布を明らかにした。続いて降雨条件, 地理的状況がEMCに及ぼす影響を回帰式で予測し, 日本全国の4地点での降雨条件を与えた際の年間流出負荷の予測値とその変動係数を導出した。その予測に基づき, 信頼性のある流出負荷量を算出するためにどの程度の降雨の採水頻度が必要になるのかをシミュレーションにより検討した。95％ 信頼区間を2倍以内程度の誤差とする場合, 水質項目によっては年間の全降雨イベントのうち半分程度を採水する必要があることを明らかにした。

Nitrogen and phosphorus associating with different size suspended solids in roof and road runoff in Beijing, China.

Roofs and roads, accounting for a large portion of the urban impervious land surface, have contributed significantly to urban nonpoint pollution. In this study, in Beijing, China, roof and road runoff are sampled to measure the suspended solids (SS), nitrogen (N), and phosphorus (P) contained in particles with different sizes. The SS content in the road runoff (151.59 mg/L) was sevenfold that in the roof runoff (21.13 mg/L, p < 0.05). The SS contained more coarse particulates in the roof runoff than in road runoff. The small particulates in the range of 0.45-50 μm consisted of 59 % SS in the roof runoff and 94 % SS in the road runoff. P was mainly attached to particle sizes of 10-50 μm in the roof (73 %) and road (48 %) runoffs, while N was mainly in a dissolved phase state in both runoffs. So, the different associations of N and P raise a challenge in preventing stormwater pollution in urban environments.

분산형 저류시설-하수관망 네트워크 시스템의 입자군집최적화 기반 모델 예측 제어

도심지역의 하수관거 시스템은 우수 수용능력 및 하수 월류 발생 등의 시스템의 한계점을 가지고 있어, 강우시 우수 유출수로 인한 침수저감과 더불어 도시비점오염원의 저감에 모두 대응할 수 있는 저류시설의 도입이 주목받고 시작하였다. 최근 환경부에서는 방재적 우수관리와 더불어 합류식 하수관거 월류수, 분류식 우수관거 유출수 처리를 포함하는 다기능 저류시설을 "하수저류시설"이라 통칭하고, 이의 도입을 적극 추진하고 있는 실정이다. 반면 대규모 단일 저류시설 설치의 경우에는 공간 확보의 문제가 발생할 수 있으며, 이에 대안으로는 중 소규모의 분산형 저류시설 설치 및 운영을 들 수 있다. 본 연구에서는 분산형 저류시설-하수관망 네트워크 시스템의 최적 운용을 위한 모델 예측 제어기법을 제안한다. 이를 위해 첫째로 네트워크 시스템의 각 구성 요소의 수리모델을 제시함으로써 보다 정밀한 하수관망 네트워크의 거동을 모사하고자 한다. 둘째로 제안된 모델을 기반으로 현재의 강우 유입량을 고려하여 각 저류조의 수위, 하수관로의 유입/유출량을 예측하여, 입자군집 최적화 알고리즘을 이용한 모델 예측 제어기법을 바탕으로 주어진 제약조건을 만족하며 상황을 바탕으로 제안된 제어기법의 사용여부에 따른 효과를 비교 분석하고, 이의 타당성을 검증하고자 한다. Urban sewer systems has a limitation of capacity of rainwater storage and problem of occurrence of untreated sewage, so adopting a storage facility for sewer flooding prevention and urban non-point pollution reduction has a big attention. The Korea Ministry of Environment has recently introduced a new concept of "multi-functional storage facility", which is crucial not only in preventive stormwater management but also in dealing with combined sewer overflow and sanitary sewer discharge, and also has been promoting its adoption. However, reserving a space for a single large-scale storage facility might be difficult especially in urban areas. Thus, decentralized construction of small- and midium-sized storage facilities and its operation have been introduced as an alternative way. In this paper, we propose a model predictive control scheme for an optimized operation of distributed storage facilities and sewer networks. To this aim, we first describe the mathematical model of each component of networks system which enables us to analyze its detailed dynamic behavior. Second, overflow locations and volumes will be predicted based on the developed network model with data on the external inflow occurred at specific locations of the network. MPC scheme based on the introduced particle swarm optimization technique then produces the optimized the gate setting for sewer network flow control, which minimizes sewer flooding and maximizes the potential storage capacity. Finally, the operational efficacy of the proposed control scheme is demonstrated by simulation study with virtual rainstorm event.

Characteristics of combined sewer overflows in Shanghai and selection of drainage systems

The overflow frequencies of combined sewer systems (CSSs) along Suzhou Creek in Shanghai are definitely lower compared with low interception ratio and design expectation. This noteworthy phenomenon was analysed and the results indicate that large sewer storage capacity due to a dense interconnection between sewer systems, flat pipe slope and pump drainage pattern, as well as the spatial-temporal difference of rainfall on a large catchment that is integrated by the connected network, lead to the overflow frequencies of combined sewer overflows (CSOs) along Suzhou Creek that are much less than those of designed and of Japanese counterparts. The drainage hydraulic model was used to simulate the performance of typical CSSs in Shanghai centre area to further explain the phenomenon. Meanwhile, as separate systems have serious illicit connections and are subject to heavy wet weather pollution in Shanghai, separate systems did not show the expected advantage in nonpoint pollution control. Thus, keeping old CSSs in the Shanghai downtown area seems to be of great value with respect to the control of urban non-point pollution.

Use of GIS in Urban Storm-Water Modeling

Use of Geographic Information Systems GIS in urban stormwater modeling is a growing technology designed for storing, manipulating, analyzing, and displaying data in a geographical context. It can be characterized as a software package that efficiently relates geographic information to attribute data stored in a database. While GIS has been around since the 1960s Tsihrintzis et al. 1996 , it is only with the emergence of personal computers in the 1970s that it has found widespread use. A full realization of the potential of GIS awaits standardized and more accessible databases. Urban nonpoint pollution produces stormwater that is polluted with, for example metals, pesticides, and nutrients due to land use

Mapping hazard from urban non-point pollution: a screening model to support sustainable urban drainage planning

Non-point sources of pollution are difficult to identify and control, and are one of the main reasons that urban rivers fail to reach the water quality objectives set for them. Whilst sustainable drainage systems (SuDS) are available to help combat this diffuse pollution, they are mostly installed in areas of new urban development. However, SuDS must also be installed in existing built areas if diffuse loadings are to be reduced. Advice on where best to locate SuDS within existing built areas is limited, hence a semi-distributed stochastic GIS-model was developed to map small-area basin-wide loadings of 18 key stormwater pollutants. Load maps are combined with information on surface water quality objectives to permit mapping of diffuse pollution hazard to beneficial uses of receiving waters. The model thus aids SuDS planning and strategic management of urban diffuse pollution. The identification of diffuse emission ‘hot spots’ within a water quality objectives framework is consistent with the ‘combined’ (risk assessment) approach to pollution control advocated by the EU Water Framework Directive.

Lawns and Toxins

Abstract This paper surveys the problems of contemporary urban ecology through the lens of lawn chemical usage, exploring the difficulty of explaining and managing urban ecological dilemmas that, though built from the disaggregated choices of individuals, aggregate into large and serious issues. Introductory discussion surveys the seriousness of lawn chemicals as urban non-point pollution sources and suggests why the issue, and problems like it, it understudied. Analysis proceeds with a case study from the United States city of Columbus, Ohio, utilizing formal survey techniques and aanlysis of county assessor's data. The results suggest lawns and lawn care chemicals are expanding with urban sprewl and that users of high-input lawn chemical systems are more likely to be wealthy, well-educated, and knowledgeable about the negative environmental impacts of the actions than non-users. Further investigation demonstrates the instrumental logics of homeowners in pursuit of property values but also points to the moral and community-oriented institutions that enforce and propel high chemical use. The conclusions point to policy options for dealing with the lawn chemical dilemma but suggest the difficulties of circumventing the deeply structured roots of the problem.

Estimation of urban nonpoint source pollution in Lake Biwa Basin

This study aims to simulate pollutant runoff into Lake Biwa using the Macro Model and examine the runoff characteristics of pollutants from urban nonpoint sources. As a result of the simulations of all rivers flowing into Lake Biwa, the characteristics of urban nonpoint source pollution and the basic units of urban nonpoint pollutants in the Lake Biwa basin became clear. It was shown that the control of pollutant runoff from nonpoint sources during storm events was significant in order to protect the water quality of Lake Biwa. From these results, valuable data concerning the environmental management of the Lake Biwa basin was obtained.

Estimation of urban nonpoint source pollution in Lake Biwa basin

This study aims to simulate pollutant runoff into Lake Biwa using the Macro Model and examine the runoff characteristics of pollutants from urban nonpoint sources. As a result of the simulations of all rivers flowing into Lake Biwa, the characteristics of urban nonpoint source pollution and the basic units of urban nonpoint pollutants in the Lake Biwa basin became clear. It was shown that the control of pollutant runoff from nonpoint sources during storm events was significant in order to protect the water quality of Lake Biwa. From these results, valuable data concerning the environmental management of the Lake Biwa basin was obtained.

Design of Dual‐Purpose Detention Systems Using Dynamic Programming

Stormwater detention basins are increasingly being used to control both urban flooding and nonpoint urban pollution. In order to design such systems effectively some type of design algorithm is needed. Two different dynamic programming formulations are examined for use in the development of a general design algorithm for dual purpose detention systems. Both formulations can be used to determine the locations and required storage for each detention basin as well as the required dimensions of the basin and the associated outlet works. Importantly, the proposed formulations allow the inclusion of pollutant loads and associated constraints into the overall stormwater management problem.

Urban Storm Runoff Quality in Southeast Michigan

Methods of sampling urban runoff and its impacts on receiving waters are reviewed and classified into three types. The field designs which yield data on mass emissions are generally most useful for evaluating alternatives to control urban nonpoint pollution. Recent field sampling of urban runoff in the Detroit, Mich. area (Southeast Michigan) permits better characterization of urban runoff quality, distribution of sizes of solids in runoff, and correlations of suspended solids with other constituents in runoff. It is concluded that region-specific runoff data are useful to planners and engineers engaged in analysis of alternative control strategies. Data from Southeast Michigan indicate that certain aspects of the urban nonpoint problem are not amenable to some source controls, such as street sweeping, but suggest that hydrologic modifications, such as detention and increased infiltration, may be more effective.