Screening Of Efficient Strains Of Municipal Sludge And Optimization Of Aerobic Composting Fermentation Conditions

With the continuous development of my country's urbanization process,the amount of municipal sludge treatment has also risen linearly,and municipal sludge treatment is facing huge challenges.Municipal sludge has high viscosity,high water content,complex composition,not only rich in organic matter,nitrogen and phosphorus and other elements,but also contains a lot of toxic and harmful substances such as viruses,eggs and polycyclic aromatic hydrocarbons.Improper treatment will cause environmental pollution.Secondary pollution.Simple landfill,incineration and other treatment methods have low efficiency,high energy consumption,and severe damage to the environment.The aerobic composting treatment method,simple operation,cheap raw materials,low energy consumption,fermented products can also be used in agriculture and forestry,etc.,is the harmless,reduction,stabilization and recycling of municipal sludge treatment Effective means.In this paper,seven different functional strains were selected from the sludge,and orthogonal experiments were used to optimize the preparation of high-efficiency fermentation agent B₁,with three commercially available compound bacteria agents?B₂,B₃,B₄?,different additives,different materials,and different materials.Aerobic compost fermentation of municipal sludge.By exploring the changes of physical and chemical properties such as temperature,water content,pH value,total nitrogen content,total phosphorus content,organic matter content and total microorganisms during the compost fermentation process,we can understand the changes in the physical and chemical properties of each pile during the fermentation process The best fermentation system and the most reasonable material ratio.The following results have been achieved:1)Separate and screen 7 strains A₁-A₇ with strong enzyme activity from the fermentation products,of which A₁,A6 are Pseudomonas,A₂ is Brevibacterium brucei,A₃ is Bacillus thuringiensis,A₄ is Gordon Bacteria,A₅ is Methylophilus,A₇ is Rheinach rheinii.Then through orthogonal experiments,according to the different amount of addition ratio,determine the size of the hydrolysis circle on the medium.It was found that when the addition ratio was 1:1:1:1:1:1:1,the comprehensive enzyme activity was the strongest,and this treatment group was determined to be the best composite bacterial agent B₁.2)The four kinds of exogenous fungicides can promote the fermentation to varying degrees and speed up the composting efficiency.The reactor with B₁ added had the fastest fermentation rate and the fastest temperature rise rate,and the temperature could rise to above50?within 24 hours.The number of bacteria in the reactor without added bacteria was the smallest;the temperature of the reactor with bacteria added was long,and the TN,TP,and OM contents were higher than those without bacteria.3)In terms of heating time,maximum temperature and high temperature holding time,the effect of pilot two?ie,the volume ratio of municipal sludge to auxiliary materials is 1:1.5?is better than pilot one.The fermentation speed is the fastest and the efficiency is the highest.The fermentation period is 20 to 23 days,the maximum temperature can reach 65?,the duration of high temperature exceeds 5 days,and the nutrient content of the compost product is high.4)By comparing various physical and chemical properties during the composting process,it was found that the addition of corn stalks is beneficial to the loss of water in the heap;corn stalks,biochar,and furfural dregs have certain effects of nitrogen,phosphorus and organic matter retention;fungi B₁ has the largest total amount of microorganisms.5)During the composting process,the number of bacteria is greater than the number of actinomycetes and fungi,and the number of fungi is the smallest.The bacteria play a major role in fermentation.6)The best fermentation system is the stack 7 in the pilot experiment II,that is,200 kg municipal sludge,50 kg corn stover,5 kg biochar,50 mL of exogenous bacteria B₁ diluted to500 mL,fermentation efficiency The highest,the best nature of compost products.