Assessment of Point and Nonpoint Sources Pollution in Songhua River Basin,Northeast China by Using Revised Water Quality Model

Individual participation of pollutants in the pollution load should be estimated even if roughly for the appropriate environmental management of a river basin.It is difficult to identify the sources and to quantify the load, especially in modeling nonpoint source.In this study a revised model was established by integrating point and nonpoint sources into one-dimensional Streeter-Phelps(S-P) model on the basis of real-time hydrologic data and surface water quality monitoring data in the Jilin Reach of the Songhua River Basin.Chemical oxygen demand(COD) and ammonia nitrogen(NH 3-N) loads were estimated.Results showed that COD loads of point source and nonpoint source were 134 958 t/yr and 86 209 t/yr, accounting for 61.02% and 38.98% of total loads, respectively.NH 3-N loads of point source and nonpoint source were 16 739 t/yr and 14 272 t/yr, accounting for 53.98% and 46.02%, respectively.Point source pollution was stronger than nonpoint source pollution in the study area at present.The water quality of upstream was better than that of downstream of the rivers and cities.It is indispensable to treat industrial wastewater and municipal sewage out of point sources, to adopt the best management practices to control diffuse pollutants from agricultural land and urban surface runoff in improving water quality of the Songhua River Basin.The revised S-P model can be successfully used to identify pollution source and quantify point source and nonpoint source loads by calibrating and validating.

Optimization of Identifying Point Pollution Sources for the Convection-Diffusion-Reaction Equations

In this paper,we consider the optimization problem of identifying the pollution sources of convection-diffusion-reaction equations in a groundwater process.The optimization model is subject to a convection-diffusion-reaction equation with pumping point and pollution point sources.We develop a linked optimization and simulation approach combining with the Differential Evolution(DE)optimization algorithm to identify the pumping and injection rates from the data at the observation points.Numerical experiments are taken with injections of constant rates and timedependent variable rates at source points.The problem with one pumping point and two pollution source points is also studied.Numerical results show that the proposed method is efficient.The developed optimized identification approach can be extended to high-dimensional and more complex problems.

Sedimentation retention basin utilization for best management practice

Approaches to the artificial impoundment and theoretical design of sedimentation retention basin are reviewed with particular attention to best management practice(BMP) to control agriculture and surface runoff. Sediments retention basins are the small version of farm pond used where a criteria of farm pond is not met. Such basin traps the pollutants and suspended solids prior to entry into streams and lakes. The study is focused with special reference to the assessment and control of non point source pollution(NPSP) from the sub basin area of Tai Lake in the Xishan County of Wuxi City of China. The author suggested two different approaches to conduct this study including theoretical design for sedimentation retention basin and computation of flow, sediment transport and deposition during the artificial impoundment of retention basin for BMP's utilization. Theoretical design will provide a useful function as a first line defense against the movement of sediments and transport of pollutants into the Tai Lake while the assessment of sediments deposition will help to make its proper use and periodic cleanup.

Generation of the Data Required by AGNPS

Remote sensing techniques and geographic information systems offer a good means of collecting and manipulating the data required to assess conservation practices. A method for automatic generation of most of the data required by the agricultural non point source (AGNPS) erosion model is put forward from three sources: (1) files with contour lines from topographic maps, (2) soil mapping units from soil surveys, and (3) land cover from land sat TM image classifications.

Rapid growth of industrial nitrogen fluxes in China: Driving forces and consequences

Human activities are strongly modifying the global nitrogen (N) cycle through increasing input, N species diversity, and pool size of industrial reactive N (Nr). However, the fluxes, fates and environmental consequences of industrial Nr (excluding synthesized N fertilizer) remain poorly understood and quantified. We report here that industrial Nr flux has increased 13.4-fold over the past 30 years in China, reaching 3.7Tg N (1 Tg=10 12g) in 2008, accounting for over 50% of China's food Nr flux. Socioeconomic development (per capita GDP, urbanization and household size) significantly drives the growth of industrial Nr fluxes. This leads to "hotspots" of industrial Nr, mainly in relatively developed Eastern China. Industrial Nr loss rate during production is only 5%, much lower than that of cropland (50%) and livestock (80%). However, industrial Nr loss is point source pollution, and Nr release in concentrated doses produces serious risk in small regions. The contribution of structural N to total industrial Nr with a lifespan longer than one year (e.g., synthetic fiber, plastic) increased from 20% in 1980 to 70% in 2008. There was about 2.6 Tg N structural industrial Nr accumulated in human settlements in 2008, which could be one ex- planation of an unknown Nr sink of anthropogenic Nr input (mainly Haber-Bosch N fixation). Legacy effects caused by structural N accumulation have long-term consequences for environmental and human health, although structural N delays Nr release and reduces short-term Nr pollution. Industrial Nr use generates new features of modern global N biogeochemistry, such as increasing Nr species diversity, reducing Nr turnover rate. Future dynamics simulation of the earth system should involve industrial Nr. Explicit consideration and accounting of the fluxes and environmental consequences of industrial Nr would provide decision-makers a novel view of regional sustainable development.

AN OPTIMIZATION METHOD OF AQUATIC ENVIRONMENTAL CAPACITY FOR TIDAL RIVER NETWORK

By using the high-efficiency of four-stage calculation method named ＂channel-junction-channel＂ and considering the influence of temporal and spatial variation of aquatic environmental capacity, an optimization method of aquatic environmental capacity for tidal river network was worked out. The method not only reflects characteristics of unsteady flow with variable directions, but also indicates that aquatic environmental capacity is influenced by boundary condition and water quality standard, etc. It has been applied to the regional program of Pudong area in Shanghai, and the computed results agree well with the practical data.

INVERSE PROBLEM METHOD FOR WATER ENVIRONMENT TOTAL CAPACITY CONTROL OF A TIDAL RIVER

In this paper, an improved method for water environment total capacity control of tidal rivers was presented. The maximal capacity of point pollution sources for the Huangpu River was computed by this method, and the result was compared with the practically observed data. The numerical result shows that the method is effective and efficient.