Odor Emission Characteristics Of The Off-gas From Livestock Manure Aerobic Composting Tank And Its Bioreactor Deodorization

Aerobic composting can better realize the resource utilization of organic solid waste,but the serious malodorous gas generated during the composting process not only pollutes the environment,but also harms body health.It is an urgent problem that needs to be solved and cannot be ignored.The malodorous gas generated in the production process of livestock and poultry breeding affects the green and healthy development of the breeding industry.Among them,the resource utilization of livestock and poultry manure has the largest source of odorous gas,which is particularly worthy of attention.Biological method is a low-consumption and high-efficiency odor treatment technology,but it is affected by various factors such as source intensity and load impact in practical applications.How to deodorize stably,quickly and efficiently has become the current solution to odor in aquaculture and even solid waste resources.bottleneck of utilization.In this study,the odorous gas emitted from the continuously operating composting tank of the organic fertilizer plant was analyzed and measured,and the source intensity of odorous gas,the concentration of key pollutants and the parameters of the circulating water were analyzed and measured.The removal efficiency of the bioreactor to the key odor-causing pollutants,and the deodorization effect of the device is evaluated and compared to eliminate the odor nuisance of such odorous gases.These results were as follows:NH₃ and TVOCs are the main contributors to the malodorous gases of aerobic composting process.This topic tracks the source intensity of odorous gas from the actual aerobic composting process of livestock and poultry manure,concluded that the daily average concentration of NH₃ was 806.26 mg/m~3;the daily average value of TVOCs was 44.55 ppm;and the daily odor level was 626.The results of pearson correlation and regression analysis showed that NH₃ and TVOCs had significant contributions to the odor level,which provided a target for the subsequent removal of major odor pollutants.The rhamnolipid-enhanced bioscrubber application device has achieved a certain deodorization effect,but it needs to be improved.Through the rhamnolipid enhanced bioscrubber（BS）pre-deodorization study,it was found that under the high-load operating conditions with an average concentration of 543.1 mg/m~3,the BS obtained an ammonia removal efficiency of 77.32%and an average elimination capacity of 46.84 g _N/m~3/h.Under the current operating conditions of BS,0.50 CMC rhamnolipid can most effectively enhance the removal efficiency of VOCs.However,in terms of shock load resistance,BS-A supplemented with rhamnolipid was superior to control group BS-B.The device plays a certain role in screening and domesticating the microbial community,which makes the microbial community structure in the BS change significantly,so as to play the corresponding nitrogen conversion and organic matter degradation,and ensure that the reactor can play a certain deodorization effect.Under the existing regulation mode,the comprehensive deodorization efficiency obtained by BTF-B is higher than that of BS-A,BS-B and BTF-A,and its application and promotion potential is greater.Two biotrickling filters（BTFs）were fabricated to treat the off-gas produced during the aerobic composting of animal manure,namely:BTF-A（packed with volcanic rock）and BTF-B（packed with ceramsite）.The removal efficiencies of BTF-B for NH₃,TVOCs,and odor level（88.78±5.03%,70.25±6.95%and 88.10±13.21%,respectively）were superior to those of BTF-A.NH₃was phase-transferred to NH₄⁺-N and then oxidized to NO₂^--N.The Simulation experiment speculates that denitrification does not occur in the system,and partial nitrification was achieved in the circulating water with a p H of 7.0 to 8.2,dissolved oxygen（DO）content of 1 to 3 mg/L,and an average free ammonia（FA）content of16.65 mg/L.Moreover,partial nitrification in circulating water made denitrification by ANAMMOX possible.In particular,the abundance of Proteobacteria in samples of BTF-B accounted for 83.50±11.08%of the total bacteria,which was consistent with the increase in NH₃removal capability.With traditional AOB faded in the BTF biofilms,another newly reported AOB,Ca.Nitrosoglobus dominated and prompted the system to achieve partial nitrification.In addition,Ottowia sp.,Comanonas sp.,Alkanibacter sp.,Paracoccus sp.,and Ralstonia sp.were responsible for deodorization by degrading VOCs.A deodorization mechanism based on Ca.Nitrosoglobus and Ralstonia sp.in the biofilm on packings was proposed.Overall,this study provides favorable evidence on the future applicability of BTFs in a capacity of 20-30 m~3 livestock manure compost tanks.Therefore,the BTF is an effective measure to solve the odor problem of livestock and poultry manure composting process.The research results provide an application demonstration for solving the odor problem caused by the recycling process of livestock and poultry manure.The promotion and application in the field of gas treatment has laid the foundation.