Research On Combined Process Of Negative Pressure Denitrification And MBBR Of Swine Wastewater

China is a major country in the world for pig breeding and export.The pig industry has become an indispensable part of my country’s agricultural economy.The annual high slaughter volume has driven the rapid development of the pig breeding industry,but at the same time it has also brought a serious environment.The hidden safety hazards are focused on the harmless treatment of waste at the end of the industry,of which the inevitability is the treatment of pig-raising wastewater.Pig farming wastewater generally contains pig manure,pig urine,residual feed,and site flushing water.One of the more commonly used pig farming wastewater treatments in my country is dry manure removal technology.This process has been used due to its mature technology and the ability to save a lot of tap water.Favored by domestic pig breeding companies.However,the characteristics of high ammonia nitrogen and low carbon-to-nitrogen ratio are common in the dry cleaning pig wastewater.In the treatment project using traditional biological denitrification process,the water quality characteristics of the pig-like wastewater will have insufficient carbon source in the denitrification process and the denitrification process.The problem of being inhibited and thus affecting the final denitrification effect.Although the physical and chemical denitrification method can reduce the ammonia nitrogen concentration in the water,the high concentration of organic matter in the pig wastewater still needs to be removed by biochemical reactions,and the common physical and chemical denitrification processes often have problems such as high energy consumption and serious secondary pollution.Therefore,a more economical,efficient,and environmentally friendly process for treating pig-raising wastewater with a low C/N ratio remains to be developed.Based on the investigation of physical and chemical denitrification method and biological denitrification method,this paper designs negative pressure denitrification reactor and MBBR reactor,and realizes stable operation after installation and commissioning,and proposes a technical route based on combined negative pressure denitrification and MBBR operation.That is,through the front-end suction to form a negative pressure environment to achieve the purpose of removing part of the ammonia nitrogen in the water body,increase the C/N ratio in the wastewater,and create favorable conditions for the subsequent biological denitrification process.At the same time,the negative pressure denitrification process is different from other processes.The physical and chemical denitrification process does not cause secondary pollution in the process of wastewater treatment,and has no high requirements for the subsequent biochemical process,which reduces the difficulty of process operation as a whole,so as to achieve efficient and stable removal of low C/N ratio pig breeding wastewater New coupling process.Under the condition of simulating wastewater in the laboratory,through single factor influence experiment and response surface analysis,the design-Expert software was used to optimize the process conditions of the negative pressure denitrification reactor,and the influence of each factor on the denitrification process was determined.The degree is:p H>vacuum>time>initial concentration.At the same time,the optimal process operating parameters of the reactor are obtained: p H value is 10.5,vacuum degree is 0.095,time is180 mins,and initial concentration is 1380mg/L.The determination of the optimal process parameters for negative pressure denitrification is conducive to the efficient and stable operation of the reactor,and at the same time provides a guarantee for the subsequent MBBR stage.This study is based on the A/O process and constructs the MBBR reactor with biological filler carrier.After the pre-filming and start-up of the reactor is completed by the suffocating method,the COD,ammonia nitrogen degradation process and the biological community change in the system are analyzed.Analysis revealed that the removal rate of COD in the reactor was increased from the initial 38% to 83%,and the removal rate of ammonia nitrogen was increased from the initial 8% to 40%,realizing an increase in the removal rate of COD and ammonia nitrogen.At the same time,in the domestication stage,the biological community structure in the system is changed by increasing the ammonia nitrogen concentration in the influent and reducing the COD/TN ratio,so that Comamonas,Hydrogenophag and other denitrifying bacteria with relatively low relative abundance in the early stage will be The relative abundance value gradually increased in the later period,indicating that with the increase of the influent ammonia nitrogen concentration or the decrease of COD/TN,the growth and development of related denitrification bacteria can be promoted.The negative pressure denitrification process was coupled with the MBBR process and used to treat the waste water from dry cleaning pigs.The specific treatment efficiency was explored,and the cost calculation of the combined process was carried out.Research shows that the COD removal rate of the coupling process is 85±5%,and the ammonia nitrogen removal rate is 42±6% in the whole process.Compared with other processes,this process combination does not require special reaction conditions for the biological denitrification process,and the front-end negative pressure denitrification experiment did not produce secondary pollution.The overall requirement for process conditions is low,and it is environmentally friendly.The coupling process.At the same time,after cost accounting,the total operating cost of the coupled process is 4.75RMB/m3.In the later stage,the cost can be continuously reduced by further optimization of process conditions,recovery of ammonia and resource utilization,etc.