Study On The Characteristic Of Phosphorus Removal Efficiency And Changes In Phosphorus Forms Using Three Kinds Of Straw Material To Treat High-loading Swine Wastewater

The agricultural pollution has become a main source of the environmental pollution,especially the phosphorus(P)loaded contribution rate of livestock and poultry industry has reached 37.9%.Constructed wetlands are an important measure for treating pollution water.However,wetland plants are difficult to tolerate because nutrient concentrations of biogas slurry are too high.Herein,we should reduce nutrient concentrations using appropriate measures.In this study,we selected three common crop straw materials as the biological matrix materials,i.e.wheat,corn,and rice straw.A three-stage biological matrix treatment system was established in the Changsha county,Hunan province,and treated the swine water in one year.This paper showed the seasonal variation characteristics of phosphorus removal efficiency during the biological matrix treatment system treatment swine wastewater,and the transformation of phosphorus form,straw adsorption and degradation,sediment sedimentation and so on.Effect of biological matrix materials treatment system on phosphorus removal was investigated.The research could not only provide theoretical basis for swine water ecological treatment but also provide development for resource utilization technology.The main conclusions of this paper are as follows:(1)Results showed that phosphorus was effectively removed in the biological matrix treatment system.The removal efficiency of TP and DIP were 33.03% and 28.62%,respectively.The average effluent concentrations of TP and DIP were reduced to 69.89±15.58 mg·L-1 and 43.89±13.08 mg·L-1,respectively.These concentrations were within the tolerance range of Myriophyllum elatinoides(<73 mg·L-1).(2)The phosphorus removal in the biological matrix treatment system was mainly based on the precipitation of particulate phosphorus,which accounted for 55.3% of TP removal.In the sediment,the main form of phosphorus are inorganic phosphorus(> 65%),and the proportion of organic phosphorus in the sediment decreases from the first stage to the third stage.(3)The phosphorus removal efficiency decreasesdue to the degradation of straw materials components,i.e.cellulose,hemicellulose.Straw materials need to be replenished after a period of operation in the biological matrix processing system.Wheat and rice straw had relatively low decomposition resistance.Addition cycle for straw materials was 3~4 months.Corn stalk had relatively strong decomposition resistance.Addition cycle for matrix materials was 4~5 months.(4)The TP and DIP removal was significantly positively related to temperature(T)and p H(P< 0.05),but there was no significant difference in DO and Eh(P > 0.05).