The Distribution Of Urban Sewage Treatment Plant Energy Consumption And Study On Working Conditions Control

There are some supporting pipe network construction problem of inadequate in most small and medium urban sewage treatment plant in our country. A lot of rain into the collection pipe network in the period of rainfall, make a large fluctuations of the water quality and quantity. Frequent changes of influent load leads to the sewage treatment process difficult to maintain stable operation at design conditions, not only affect the treatment effect, also makes part of the processing equipment departing efficient operation, reduced efficiency, increased energy consumption. High energy consumption resulting in high processing costs. As the result, a number of small and medium urban sewage treatment plant operations due to shortage of funds and unsustainable. To reduce the energy consumption of wastewater treatment plant, wastewater treatment technology research based on the analysis of the influent load variation on the operating conditions of the control measures to ensure that the sewage treatment effect and can effectively improve equipment efficiency, reduce energy waste. In recent years, the standard of the original main sewage treatment to remove carbon-containing organic compounds present to remove both carbon, nitrogen and phosphorus removal, which made more stringent requirements in the sewage treatment plant process control operating conditions.This article is based on the field survey and data collection of a sewage treatment plant’s influent load and energy consumption in Chengdu Wuhou district. After understand the treatment process of the plant, analysis the change of influent water quality and quantity and the energy consumption distribution of pumps, fans and other equipment. On this basis, by the reasonable adjustment of pumps, fans and other power equipment operating conditions, improve equipment efficiency, to reduce power consumption purposes. The main results of this paper are summarized below:(1) The direct energy consumption of sewage treatment plants including the lift pump power consumption of regulation pool, the aeration wind electrical energy consumption of aerobic biological treatment tank, secondary settling tank sludge return pump power consumption, sludge dewatering machine equipment power consumption, and electronic control systems, lighting and other forms of electricity consumption. Indirect energy consumption includes the added pharmaceutical when sludge dewatering. In the survey. The average tonnes of water’s electricity consumption is 0.355kW·h/m3, the average electricity consumption of the unit COD removal is 1.250kW · h/kgCOD in 2015. According to the wastewater treatment plant energy consumption statistics, power consumption of lift pump and aeration fan accounted for more than 65% of the total power consumption.(2) Wastewater treatment plant supporting pipe network is a rainwater and sewage combined system. During the period of rainfall, the quality of inflow water influenced by the rainfall. High in summer and low in winter. In the wetland survey, inflow water in the range of 90% to 100% of the design scale only 57.44% of the time, the COD concentration in the time interval from 85% to 100% of design capacity accounted for 66.22% of the year 2015. Frequent fluctuations in influent load leads to pumps and fans and other power equipment designed to operate long-term deviation from the condition, reducing efficiency, energy loss increases. So it need equipment operating conditions to be adjusted to restore efficient operation.(3) In order to achieve the requirements of energy saving in different influent load of the sewage treatment process. This paper will use the programmable logic controller (PLC) and the method of inverter, adjust the lift pump and aeration blower operating conditions, to optimize the process operation mode. Based on the results before and after regulation, in 2015, the pump regulating the maximum saving rate is 25.01%, the largest electricity savings is 337.88kW·h/d, annual festival regulation can amount 102935.02kW·h by the pump, regulation biggest fan operation saving rate of 14.24%, the largest electricity savings of 267.42kW · h/d, through the fan regulation section of full year amount of 70309.54k W·h. Regulating electricity savings of pump and fan accounts for the total annual electricity consumption of 14.68% in 2015.(4) Except to adjust enhance pumps and aeration fans to reduce the power consumption, We can also through the standard process of operation, strengthen equipment maintenance frequency and introduce more efficient power plants and other ways to achieve the energy saving in the process of sewage treatment.