Gas Pollutant Detection And Trimethylamine Treatment In Fishmeal Production Process

As a protein feed material,fish meal is a product obtained by cooking,pressing,drying and pulverizing whole fish or the remainder of its processed products.In the past five years,our country’s annual consumption of fishmeal is about 2.5 million tons,of which about 1.5 million tons are imported.At present,the production process of fish meal is basically the same.During the cooking and drying process,a large amount of water vapor containing organic matter is produced,which is unpleasant and harmful to the environment.The amount of waste gas produced by drying fish pulp accounts is about 80%of the total waste gas.Therefore,it is an urgent problem to be solved for the sustainable development of the fishmeal industry by analyzing the organic matter components in the waste gas of fishmeal production and studing its treatment methods.First,we collect the fish pulp from a fish meal factory in Dalian and distill it to produce water vapor and waste gas(hereinafter referred to as fish pulp drying waste gas).Collect them with aluminum foil bags and analyse them by gas chromatography-mass spectrometry.The organic matter in the waste gas and its condensate is 9 species and 18 species.After analyzing the content of organic matter and its hazard,trimethylamine was determined as the research object.Repeat the distillation of the fish pulp three times,and the content of trimethylamine in the exhaust gas and its condensate detected by gas chromatography is 7588.22±1353.07 mg/m~3and 473.04±37.18 mg/L.Second,we build a biological trickling filter(inner diameter of 70 mm,effective filling height of 230 mm),and film it with activated sludge successfully.Investigate the effect of trimethylamine gas inlet concentration,gas empty bed time(EBRT)and eluent flow rate on the treatment effect of trimethylamine gas.Deriving optimal operating conditions for biotrickling filters:the inlet concentration of trimethylamine is 200～400 mg/m~3,EBRT=90 s,and the flow rate of the eluent is 20 m L/min.Under these conditions,we continuously treat trimethylamine gas for 7 days and the removal rate of trimethylamine is 54.97%～69.84%.Then,use the biological trickling filter to treat the fish pulp drying waste gas.The removal rate of trimethylamine was over 92%,and nitrogen nitrate was detected in the leaching effluent.It can be seen that the biological trickling filter has achieved the function of degrading and converting trimethylamine.Third,we isolate a yellow strain from the biological trickling filter by using trimethylamine selective medium.Then,we sequence its 16S r RNA genome,and it’s preliminarily identified as Bacillus subtilis.We also verified that it has the function of degrading trimethylamine at the same time.The results of this study provide technical support for the healthy development of the fishmeal industry.