Filtration technology of poultry washing wastewater based on maize stover filter media

Treatment of livestock and poultry wastewater has brought tremendous pressure to the surrounding environment, particularly to the large-scale and intensive breeding and mechanized farming. Poultry washing wastewater generally contains complex components, a large amount of solid particle sludge, and high ammonia nitrogen content, leading to single pretreatment means and high treatment costs. Alternatively, easily accessible, low-cost corn stalks can be used as filter materials to pretreat the poultry washing wastewater for high efficiency of wastewater treatment. It is an economical and effective way to treat waste with waste, thereby realizing the resource utilization and harmless treatment of poultry washing wastewater. Filtration pretreatment can also effectively remove suspended solids in aquaculture wastewater. Since the filtered solids were subjected to composting treatment, where together returning to the field for effective use of resources. Post-biochemical treatment was performed on the filtered wastewater, and further greatly reduced the processing costs of aquaculture wastewater. This study aims to explore the filtering law of corn stalk as a filter material, and the effects of corn-stalk particle size, compaction, and filling height of filter material on the filtration pretreatment of poultry-washing wastewater. A structural model was also established for the poultry-washing wastewater filtration device. The filtration characteristics of main pollutants were investigated in poultry washing wastewater under different particle sizes, filter thicknesses, and compactions, where the boundary conditions of each factor were determined. A single factor test was carried out to determine the boundary condition of parameters. The three-factor three-level orthogonal test was designed to clarify the effect of corn stalk filter on the poultry-washing wastewater. The results show that the filter material presented the best filtering performance when the particle size of corn stalk was 1cm, the compaction degree was 1.4 times density (74.93kg/m3), and the filling height of filter material was 50cm. The Total Solids (TS) removal rate of poultry-washing wastewater was 31.22%, the Volatile Solid (VS) removal rate was 44.51%, the Chemical Oxygen Demand (COD) removal rate was 24.07%, and the NH4+-N removal rate was 21.20%, indicating an excellent filtration performance. The anaerobic fermentation efficiency of filtered poultry-washing wastewater was much higher than before and after filtration. Under the same conditions, the anaerobic fermentation time of filtered poultry-washing wastewater was shortened by about 50%, which was of great significance to reduce the operation cost and the floor area of the project. The structure model was built for the poultry-washing wastewater filtration device using experimental parameters. The finding can provide a promising theoretical basis to develop the straw filtration equipment for aquaculture wastewaters.