The Study On Forecasting Of Urban Sewage

Urban drainage system design is a massive project which makes great contribution to the present and the future. To forecast urban water drainage accurately is the foundation of drainage systems in urban planning and construction. In order to implement the relevant drainage standard system and taking the dynamic nature of planning into account, it is necessary to strengthen the relevant prediction model and do well in linking up with the drainage system.The subject "design of integrated assessment of typical urban drainage engineering and improvement" is one of national science and technology projects in the "Water Pollution Control and Treatment" subject. The paper gives a detailed introduction to the urban drainage design at home and abroad and the key factors of planning; at the same time, this paper gives a systematic introduction to the contents of urban sewage system, by comparing with the results of different models carefully, the forecasting model for municipal sewage, as well as the predictive model for regional sewage and industrial wastewater are designed. This paper uses carrying capacity and economic level to measure the relevant factors. By analyzing the prediction models of population, the Combined Model is set up for predicting the population. The research of forecasting for urban wastewater discharge is the key part of the paper. The main work and results are showed as follow.(1) By Appling prediction models basing on macro forecasts of urban sewage discharge, the total discharge of sewage of Shanghai in 2010,2011,2012,2013,2014 and 2020 are 2.418 billion tons,2.529 billion tons,2.657 billion tons,2.802 billion tons,2.966 billion tons and 4.196 billion tons. By 2020, the level of the total sewage discharge is 1.8 times as 2009 in Shanghai, life and other water volume is 2.1 times as 2009, while industrial waste water is expected to reach 52% as 2009. Among them, the municipal sewage volume is a larger proportion of emissions in Shanghai, having a big increase. According to the industrial and domestic wastewater reuse rate in Western developed countries, the available sewage effluent can reach to 1.807 billion tons and 3.059 billion tons in Shanghai in 2010 and 2020. Sewage recycling is a huge treasure trove of resources, it is great significance to the sustainable development of Shanghai, which is worthy of paying attention.(2) The prediction model of emission of municipal sewage basing on regional design is formed by the regional population forecasting model, the fixed water consumption, and the emission factors constitute a comprehensive sewage. According to Emission factors, water consumption quota basing on environmental and economic scale, ecological footprint regions of a million yuan GDP value as well as urban ecological footprint clustering features, urban planning is divided into four categories. The choice and determination of planning factors of sewage emission prediction model is measured and restrained by according to the bearing capacity of the ecological environment and economic level, which is more scientific and accurate, predicting water and drainage guide the planning and design effectively.(3) According to the current population characteristics, scope and predicting the actual situation of the city, also combined with forecast requirements, the prediction model basing on trend extrapolation, Grey GM (1,1) model and regression analysis is established to predicting the population of the urban, two examples of Shanghai and Hefei. According to the data of population in the "Shanghai Statistical Yearbook" and "Hefei Statistical Yearbook", the total population of Shanghai in the year of 2010,2011.2012,2013,2014 and 2019 are 1958 million,2001 million,2046 million,2092 million,2140 million and 2402 million. The total population of Hefei in the year of 2009,2010,2011,2012,2013 and 2018 are 487 million,492 million,498 million,503 million,509 million and 536 million. Due to the different statistical standards, the data of the population in the sixth census and Yearbook are different, but have shown that the current development of Shanghai were under heavy population pressure, and the population of Hefei was steady growth.(4) According to the gross value of industrial production for industry and environment-related data of the year of 2007-2009 in the "China Statistical Yearbook", the 38 units of industrial output value of industry waste water equivalent is calculated by adjusting the value of GDP at comparable prices. According to forecasts of regional or planning area of the industry and its major corporate-owned industrial output value, the corresponding area of industrial waste water emissions can be calculated for macro and micro areas, especially in regional industrial wastewater emissions for the forecast, having an important significance in the region Drainage network planning.These Analysis show, the prediction model and method presented here is rational and feasible, providing theoretical guidance to the planning of urban and drainage pipe network, providing a guarantee for building water saving society and offering useful reference to other prediction of city.