Study On The Potential Of Save-energy Of Urban Sewage Treatment Plant

With the propulsion for the construction of the ecological civilization and implementation of energy conservation and emission reduction, the construction of the urban sewage treatment plants have increased rapidly in quantity throughout the country. To the end of March 2014, the daily capacity for sewage treatment has been more than 153 million cubic meters, which plays an important role for protecting the water environment resources. However, the urban sewage treatment is a high energy-consuming industry, and its stable operation needs a good deal of energy consumption, which increases the pressure of energy of our country. Therefore, for alleviating the shortage of energy and energy conservation and emission reduction, it will play a positive and significant role to study on the energy consumption for sewage treatment plant in the current situation, put forward the saving-energy and reducing consumption plans and measures that are targeted, strengthen the management system for rational use of energy and fully tap the energy conserving potential.According to investigation for the actual operation condition of five urban sewage treatment plants in Hubei, which are different processing scale, different technologies, this paper studies including on the status quo, the constitution,the distribution ratio and consumption characteristics of energy consumption. Combined with the influencing factors, it establishes evaluation index system of energy-saving level using the method of factor analysis and Analytic Hierarchy Process(AHP), and using the system to evaluate the energy-saving level of the sewage treatment plants. What’s more, the saving-energy and reducing consumption plans and measures have been put forward in this paper, which is targeted for the most potential urban sewage treatment plants. Then comparing with the energy-saving levels before and after the implementation, and predicts the benefits after the plans implementation. The main conclusions below:(1)The average energy and flocculent consumption per ton water are 0.13 to 0.23 IV kWh, and 0.11 to 0.52.Dry sludge flocculating agent consumption per ton is 1.65 to 17 kg. The energy consumption per kilogram of COD is 0.93 to 1.94 k Wh. The energy consumption per kilogram of TN and TP are from1.91 to 17.85 k Wh and from 7.86 to 164.55 k Wh.(2) The all utilization of the equipment is not high in each factory, which is from 56.87% to 74.71%. The energy consumption of biological treatment stage is highest, which accounted for 36.71% to 63.84% and pretreatment stage places second, The energy consumption of biological treatment stage mainly concentrates on the aeration system and the blowers.(3) This paper establishes evaluation index system of energy-saving level using factor analysis and AHP, First of all, to reduce the dimension of the factors, evaluating the variable influencing factors of the sewage treatment plant energy consumption objectively through the factor analysis method, and extracting the main factors as secondary indicators for target tree of analytic hierarchy process subsequently, then calculates the weight of each secondary index. Secondly, Using AHP to establish evaluation index system, which subjectively evaluates the original influencing factors as the third indexes and calculates the weight of each index of level 3 and deals with coefficient method, which finally establishes evaluation index system of energy-saving level.(4)This paper gives the scheme analysis for energy-saving, which including the source of prevention, process control, end-of-pipe control, strengthening the management. According to the actual operation condition and characteristics of energy consumption of sewage treatment plant E which is most potential, this paper puts forward the targeted energy saving scheme that is technically feasible and economically, and evaluates the energy-saving level and predicted the benefits after the plans implementation. The comprehensive score of energy-saving level will promote from 3.1958 to 3.655, and the annual economic benefits is 222456.25 RMB,Which means Saving 100 k Wh of electricity and 625 t water, the energy and resource converts into standard coal and reductions of Carbon are respectively 120.3506 tce and 2801.84 t.