Energy Conservation Method And Technology Of Aeration In Municipal Wastewater Treatmnet Plant

Sustainable and green development becomes the subject of attention under the background of the current energy shortage. Municipal wastewater treatment plant belongs to the energy consumption-intensive industries, energy consumption of which occupies a certain proportion of the total annual consumption of all national industry, so energy saving and pollution emission reduction of municipal wastewater treatment plant is increasingly concerned by nation. But the energy saving technology of municipal wastewater treatment plant have many problems needed to solve in the aspect of power accounting management, selection of energy-saving methods and project implementation, which include imperfection of energy saving method, difficulty of technical implementation and shortage of engineering application.In order to provide practical solutions for energy saving of the municipal wastewater treatment plant.the concept of clean production and sustainable development was used as a guide to excavate the energy saving potential of the WWTP and to explore multiple ways to achieve energy saving.The research method which combined field investigation, pilot experiment research, production testing and engineering application was adopted to focus on the aeration energy saving technology of WWTP. Analysis of energy consumption distribution, excavation of energy-saving potential and establishment of energy consumption evaluating system were followed by research on influence factors of oxygen transfer performance for aerator, allocation of water quantity and accurate control technology of aeration system, which were applied on the second phase(treatment capacity of200000m3/d) of QIN HE municipal wastewater treatment plant.The main energy consumption units and equipments were put forward and the energy saving spaces of which were excavated by the Analysis on the energy consumption of municipal wastewater treatment unit and equipment. energy accounting model which was described by ratio of energy consumption to removal quality of COD, NH4+-N,TP and cost model of chemical phosphorus removal which was calculated by consumption of chemicals were established by investigating on the energy and chemicals consumption of10different treatment scale(50000-800000m3/d)WWTP in China in the perspective of energy accounting management.Unequal distributions of influent water quantity not only deteriorate the treatment effect, but also increase energy consumption of aeration equipment and reduce the space utilization of the aeration tank. The allocation method of influent water quantity was investigated, and which was applied in the municipal wastewater treatment plant.The feasibility and contribution to the biological treatment system of influent distribution allocation was researched.The result shows that water distribution allocation systems can equalize the influent water of each parallel unit, fully use the function the aeration tank,improve the treatment effect of biological treatment unit,solve the contradictions between uneven influent water quantity and not matched aeration volume,ensure treated water volume and the treatment effect.The optimal operation of the aeration system is an important means to achieve energy saving and optimize the properties of biological treatment systems for WWTP. Oxygenation capacity of aerators plays an important role in properties of whole aerator systems. The main factors affecting the properties of the aerator were investigated using pilot experiment to provide technical support for the selection and replacement of aerator.Intelligent aeration control not only improves performance of biological treatment system but also save the energy consumption. The methods and principles of intelligent aeration control was investigated, and which was applied in the municipal wastewater treatment plant of200000m3/d. Aeration model based on the ASM2d was established and solved.Blower and DO of aerobic tank were controlled by calculating oxygen demand of aerobic tank which was based on influent load. The effect of intelligent aeration control was investigated by analyzing energy saving of blower aeration and nullity of the effluent water. The result showed that the DO of aerobic tank was stably controlled and nitrite accumulation rate of31.8%was achieved,the treatment effect of biological systems was improved by the application of intelligent aeration system.Energy saving was achieved not only from the view of equipment but also from technology(Short-cut nitrification and denitrification). On the promise of that effluent NH4+-N was less than3.7mg/L and treatment quantity was basically200000m3/d, the average energy consumption and average specific energy consumption of every month were decreased by7%and9.7%respectively.