Design And Experiment Of Small Composting Equipment For Fecal Matter Of Livestock And Poultry Based On Heating By Aeration

Fecal matter of livestock and poultry is both a source of pollution and a source of organic fertilizer.The problems of dung backlog and environmental pollution caused by insufficient utilization need to be solved urgently.Using the composting equipment combined with high temperature aerobic fermentation technology to achieve fertilizer utilization is one of effective methods to deal with these problems.This thesis takes small farms and individual farmers as target groups.It aims to design a small composting equipment for fecal matter of livestock and poultry with functions of aeration,heating,mixing and heat preservation.This equipment can improve composting efficiency and controllability of fermentation conditions.So as to solve problems of large heat loss and slow decomposing rate by using traditional composting method.Through the design of equipment structure and control system,fermentation condition control based on the parameter change of composting material and air in the tank can be achieved during composting process.The design of equipment structure mainly involves two parts: composting material fermentation and heating by aeration.Firstly,completing the design or selection of each component according to results of theoretical analysis and drawing the model.Secondly,using EDEM and Fluent simulation software to analyze the effect of composting material agitation and heating by aeration based on the simplified model,so as to verify feasibility of the design.The design of control system mainly includes configuration design of touch screen interfaces,preparation of PLC program and construction of control circuit.It can achieve the start or stop control of air pump and electric heating tube based on the change of composting material temperature and oxygen concentration in the tank,and motor can also be controlled during discharging stage.Using this composting equipment to carry out experiments and evaluating actual effection.Determining the best mixing ratio of composting material and water through preliminary experiments,and then comparing composting effection under different conditions.Experimental results show that compared with natural fermentation composting,under the artificial heating condition maximum temperature of composting material is increased by about 20℃,composting cycle is reduced by about 4 days,and seed germination index(GI)is increased by about 9%.Therefore,using this equipment to compost organic fertilizer requires shorter time and attains higher fertilizer maturity.