Research And Application Of Deodorizing System For Fan End Of Negative Pressure Ventilation Pig House

In recent years,the odor problem of pig farms has received more and more attention.The number of complaints about odor pollution by residents near the farm is second only to sewage pollution.The research report shows that there are as many as 230 odor components in pig farms,and most of the odor substances are attached to dust particles.Therefore,a deodorizing net can be arranged at the end of the pig fan to provide a closed gas permeable treatment chamber or settling chamber near the exhaust airflow of the exhaust fan,so that most of the particulate matter in the exhaust gas flows within the retaining net,and simultaneously combined with the spraying water.Or deodorant and other means may play a role in eliminating the odor outside the pig house,and the low cost and good effect lay the foundation for the promotion in the production,and provide new ideas for the reduction of the odor of the livestock farm.The study is divided into three parts.The experiment 1 studied the effects of different installation distances on the wind speed in the house.A total of 6 treatment groups,blank group,2.0m group,2.5m group,3.0m group and 3.5m group were designed 4.0m group,test the wind speed and related indicators in the house,determine the optimal installation distance of the deodorizing block.In the second experiment,the deodorization effect of different sprays was studied on the basis of the test 1.Four treatment groups were designed,namely,no spray group,two layers of water spray group,the first layer of water,and the second layer of 0.5% bacteria 1 spray group.The first layer of clear water+the second 0.5%bacterial agent 2 spray group,the bacterial agent is compounded by Bacillus subtilis,Bacillus stearothermophilus,Candida utilis in a ratio of 1:1:2,detecting ammonia（NH₃）,Hydrogen sulphide（H₂S）and related indicators to determine the best deodorizing spray combination.In the third experiment,the operating cost was reduced by refluxing the microbial agent on the basis of the second test,and the deodorization mechanism was explored by measuring indicators such as biodiversity,microbial community structure and pH of the bacterial liquid.The main results are as follows:（1）The most suitable installation distance for single-layer or double-layer net is 2.5m.Compared with the blank group,when the single-layer retaining net is used and the installation distance is 2.5m,the average wind speed in the house is reduced by 1.36%（P>0.05）.When the double-layer retaining net is used and the installation distance is 2.5m,The average internal wind speed decreased by 4.77%（P>0.05）.（2）The NH₃ reduction rate of the non-spraying group,the water spray group,the first layer of clear water+the second layer of 0.5%bacteria 1 spray group and the first layer of clear water+the second layer of 0.5%bacteria 2 spray group are respectively 34.59%,60.06%,73.69% and 73.24%,among which,the ammonia removal rate of the first layer of fresh water+the second layer of 0.5%bacteria 1 spray group and the first layer of water+the second layer of 0.5% bacteria 2 spray group is significantly higher than the other two groups（P<0.05）;The H₂S reduction rate of the non-spraying group,the water spray group,the first layer of clear water+the second layer of 0.5%bacteria 1 spray group and the first layer of clear water+the second layer of 0.5% bacteria 2 spray group are respectively 41.67%,58.42%,67.79%and 72.75%,of which the first layer of clear water+the second layer of0.5%bacteria 1 spray group and the first layer of clean water+the second layer of 0.5%bacteria The ammonia removal rate of the agent 2 spray group was significantly higher than the other two groups（P<0.05）.In addition,the dust removal rate of the spray group was significantly higher than that of the non-spray group（P<0.05）.The spray group also increased the nitrate nitrogen content in the dust and reduced the ammonium nitrogen content.In order to better study the spray deodorization mechanism,this paper selects the bacterial agent 2 which is self-matched in this laboratory.（3）The results of reflux test showed that when the bacterial liquid was recycled to the third time,the deodorization effect was significantly reduced（P<0.05）,and there was no significant difference between the deodorization effect of clear water（P>0.05）,so the bacterial liquid could be recycled twice.After the use,through the intermittent spray+bacterial liquid circulation,the daily running cost can be reduced to 46.15 yuan,converted to the operating cost of each batch of pig head is 6.92 yuan/head.Compared with clear water,the addition of microbial agents can lower the pH of water,increase the content of nitrate nitrogen,reduce the content of ammonium nitrogen,increase the diversity of bacteria in water,change the structure of bacterial community,and improve the nitrifying bacteria in water.The average abundance reduces the average relative abundance of denitrifying bacteria.In summary,in this test,the optimal installation distance of the deodorizing net system is 2.5 m for the first layer and 3.0 m for the second layer.The spray combination of the deodorizing net system is the first layer of clean water+the second layer of 0.5%.When the bacterial liquid 2 has significant NH₃ and H₂S emission reduction effects,the emission reduction rate is about 73%,and the price is low;the bacterial liquid can be recycled twice,and the running cost can be reduced by the refluxing liquid+intermittent spray.To each pig6.92 yuan;deodorant network system deodorization mechanism may be 1)remove dust particles;2)reduce pH;3)increase the number of bacteria,change the bacterial community structure,promote the conversion of ammonium nitrogen to nitrate nitrogen.