Study On Treatment Of Odor Waste Gas From Fish Meal Production By Biological Process Combined With Thermal Combustion

Odor pollution refers to all the stimulating olfactory organs which cause people unpleasant and damage the environment and it is a typical pollution in the world.In2013,the State Council issued the Action Plan on Prevention and Control of Atmospheric Pollution.The CPC Central Committee and the State Council attached great importance to protect atmospheric environment.In August 2016,the government of Weihai has increased the control for local fishmeal processing enterprises.The government of Weihai orders the local fishmeal processing enterprises install deodorant equipment within a specified time limit.Therefore,we proposed to deal with the waste gas with the process of of bio-law-based joint boiler thermal combustion.Firstly,we do a small experiment and evaluated the effect of biological treatment for fish meal processing waste gas.Based on the feasibility of biological method,we do further exploration for the best operating condition of biological washing pretreatment and biological drop filtration depth.According to the operating condition of the pilot test,we design and manufacture the biological deodorizing equipment for 5000m³/h and ran a four-month commissioning operation to explore the result of massive biological deodorization system.We expect that we can provide reference and guidance for the industrial application of biological deodorization technology.The fishmeal waste gas was pretreated by biological washing process and the result showed that the efficiency will be affected by the amount of spray,air inlet flow and the MLSS of washing liquid.When the inlet flow is 12m³/h and the spray amount of washing liquid is 6L/h⁷L/h,the operation efficiency of the biological scrubber is high.The effect of MLSS on the operation efficiency of biological scrubber is not obvious and the biological scrubber can be operated directly with activated sludge liquid as detergent solution.The removal rate of NH₃ can reach about 80%,the removal rate of trimethylamine can be about 75%and the removal rate of H₂S can reach over 90%.The fish meal waste gas was aftertreated by biological drop filtration process and the result show that the operation efficiency of the bio-filter tower is high.When EBRT is 50s and spray density is 1m³/?m²·h?,the operation efficiency of the bio-filter tower is highest.The removal rate of NH₃and trimethylamine can reach about 85%and the removal rate of H₂S can reach over 90%.The adjusting ability of the bio-trickling filter is strong.In the case of high fluctuation of pollutant concentration,the removal rate of pollutant is maintained at about 85%,and the stability is high.The massive biological deodorization system shows high operation efficiency during the four months of commissioning.The test results indicate that the discharge rate of pollutants has reached the A standard of GB 14554-1993“odor pollutants discharge standard”.However,the concentration of odor is maintained above 20000?dimensionless?,which does not meet the standard of the A level and cannot discharge directly.Therefore,we try to feed the fish meal waste gas into the boiler for thermal combustion to reduce the odor concentration.After many irregular tests by environmental monitoring departments,the index of odor concentration was reduced to2,000 times?dimensionless?and can meet the standard.The one-off investment of the biological deodorant system is?300,000 and the total cost is?2.60 per 1000m³.Comparing with low-temperature plasma and photocatalytic oxidation and other waste gas treatment processes,the biological deodorizing system has the advantages of high stability and low running cost and it has great potential for industrial application.