Evaluate On Energy Consumption And Research On Energy Saving Way For Municipal Wastewater Treatment Plant

To construct wastewater treatment plant is the most effective and significant solution for water pollution control.So in recent years more and more wastewater treatment plants have been built up in our country.But in the construction of wastewater treatment plants,people pay more attention to the investment,and the reliability and advancement of the process,care little about operation management after construction, which makes many wastewater treatment plants can not normally run because of higher running cost.So the paper investigate the actual operating conditions of several commonly used wastewater treatment technology,analyze its energy consumption composition,explore the way of the city wastewater treatment plant to save energy and reduce consumption.Major conclusion is as follows:(1) In urban sewage treatment plants,the energy consumption of secondary treatment unit system accounted 60%of total energy consumption,the pre-disposal part occupies 28%,sludge disposal 10%.Power consumption mainly occurs in the sewage upgrading system,oxygen systems of the biological unit and sludge treatment system, and respectively accounted 25%,55%and 13%of the total power consumption,which are the key parts of saving energy and reducing consumption.(2) The power consumption of Aeration units in the total power consumption of sewage treatment plants accounted for the largest proportion,reaching 50-60%.In oxidation ditch aeration process,the power consumption value of brush aerator is higher than other processes.The main reason is that brush aerator using high-low-speed operation which has energy-saving effect with a certain degree,but compared with the microporous aeration,the oxygenation capacity is lower,the number of operation is much more,resulting in higher energy consumption.(3) Energy consumption of sewage upgrade unit is also high,accounted 25%of total energy consumption,so the pump lift must be determined by accurate calculating the head loss,estimation method would be not appropriate.Selection of the pump type should take speed pump and variable-speed pump with a combination to adapt to flow changes and energy saving.(4) Energy consumption of the sludge disposal system mainly due to too large dewaterer capacity,the inefficient work in most time and flocculant usage to improve the dewaterer capacity.So the designers should accurately figure out sludge production,moisture content and so on,reasonably choose dewaterer,determine optimum dosage by experiment.(5) The operation of oxygen supply equipment should be based on dissolved oxygen demand of biological treatment unit,using on-line and feedback measurement to control the number of aeration equipment and the operation power.The aeration system should be designed as speed and variable-speed combination mode.(6) Analyzing the running cost of the wastewater treatment plant,electricity costs accounted 38%-52%of total operation cost without considering depreciation costs,so it's still higher.(7) Sewage treatment plant generally exist the problem of practical inflow less than design scale,which make most sewage plant equipment inefficiently work,resulting in energy wasted,in order to achieve the purpose of saving energy and reducing consumption,designers must pay attention to the point.And the design of water quantity and water quality must be pay attention.