Research And Design Of Drum Composting Box For Household Manure

Based on the national background,this paper analyzes the pollution and resource of human feces,and emphasizes the importance of transforming human feces into useful resources.In view of the unreasonable treatment of human feces,environmental pollution and wasting resources in China,this paper analyzes various methods of human feces treatment,and chooses composting treatment of human feces.For that,a kind of household composting box is designed.The household composting box is directly connected with the toilet through the pipeline,which is applied to the collection and treatment of household feces,so as to achieve the purpose of resource and harmless treatment of household manure.First of all,the composting technology was analyzed to determine the technology suitable for household composting box.The changes of related parameters in the process of aerobic composting were analyzed to provide theoretical basis for composting experiment.Secondly,according to the process requirements of composting box,the main system design of household composting box is completed,including the outer box,feeding system,composting mixing system,heating system,ventilation system and control system.The feeding system can realize the automatic supply of composting auxiliary materials in the composting process.The composting mixing system can complete the solid-liquid separation and material mixing.The discrete element software EDEM is used to analyze the mixing performance of the composting drum.Taking the material mixing uniformity as the index and the inner wall structure of the composting drum as the factor,the influence of the smooth wall and U-shaped transverse wall on the mixing effect is analyzed respectively,and the results show that when the inner wall of the composting drum is a U-shaped horizontal bar The mixing degree of the material is 93.76%,which is higher than that of the smooth one.The designed ventilation system can provide oxygen for aerobic composting,and the total amount of ventilation required for composting process is 7.42L/min.Then,ANSYS Workbench finite element analysis software is used to analyze the key parts of the composting box spiral screw rod and composting drum,and the results meet the design requirements.According to the modal analysis of the screw rod,the minimum critical speed is 2229.18r/min,which is faster than 90r/min of the actual working speed.In addition,according to the actual situation of the compost drum transient dynamics analysis,the results meet the design requirements.Finally,using a household composting box prototype make a 30-day continuous aerobic composting experiment.The relevant parameters in the process of aerobic composting,such as stack temperature,p H value and O₂ concentration,were detected and analyzed.The results showed that the changes of relevant parameters met the requirements of aerobic composting process.After 30 days of aerobic composting test,the moisture content of compost finished fertilizer was 28.9%,the seed germination rate was 82.5%,and the seed germination index was 86%.It was proved that the finished fertilizer was completely decomposed.The results showed that the relevant parameters met the relevant national standards.The mortality rate of Ascaris eggs was 98.5%,which was higher than 95%of the relevant standards.It was proved that the aerobic composting process of household composting boxes could effectively eliminate the pathogens in human feces.