Study On Treatment Of Livestock Wastewater With Physical Adsorbents And SBR

Livestock wastewater is a kind of high concentration organic sewage,which is rich in nitrogen,phosphorus,organic substances and suspended solids.It is not only a critical pollution to surrounding soil,water and air but also a certain threat to human health as it is discharged into the environment without effective treatment.Therefore,it is particularly important to improve the efficiency of livestock wastewater treatment system.Physical adsorbents are widely used in the field of wastewater treatment because of their stronger capacity,lower price and greater sources.However,the types of physical adsorbents are complex and vary in their application effects.The purpose of this study is to select the most effective one from three adsorbents that are anionic resin,powdered activated carbon and graphene oxide,and apply it to enhance SBR system efficiency.The result is also analyzed to find out the adsorbent dosage and operation effect for SBR system.The main results as follow:1.Under the condition of shaking at 25 °C for 5h with 130 r/min,the transparency of livestock wastewater treated by PAC was better than graphene oxide and anion resin.The removal rate of COD was 78.89%±2.611% with 40g/L PAC applied,which was significantly higher than that of anion resin and graphene oxide(p<0.05);the removal rate of ammonia nitrogen was 34.39%±0.929%,which was significantly higher than that of anion resin.When the dosage of PAC was 60g/L,the removal rate of total phosphorus reached the maximum value of 84.66%.Therefore,PAC was the best for livestock wastewater among the three physical adsorbents.2.Under the operation conditions of 20 min water inflow,50 min stirring,240 min aeration,120 min sedimentation,10 min drainage and 50 min idleness in each cycle,with21 days of acclimation of activated sludge,MLSS increased from 3.578g/L to 4.7g/L;MLVSS increased from 2.141g/L to 2.5g/L;SV30 was 50% in the initial stage and maintained at 40%-42% in the later stage;SVI was 139.742ml/g in the initial stage and maintained at 85-90ml/g in the later stage.The final removal rate of COD was above50%,ammonia nitrogen was above 90%,total phosphorus maintained about 80%.3.With 5d operating,the effluent of the combined treatment of SBR and PAC group was clear and transparent,which was better than that of the SBR control group.MLSS,MLVSS,SV30 and SVI in the combined treatment group were maintained 4.8-5.1 g/L,2.5-2.9g/L,39%-41% and 79-82 ml/g,which were close to those in the SBR.The results showed that the removal rates of COD,ammonia nitrogen and total phosphorus in SBR were 49%-56%,91%-95% and 90%-84%.By contrast,the removal rate of COD,ammonia nitrogen and total phosphorus in combined group were 76%-92%,87%-92% and 67%-89%.The SBR combined with PAC accelerates the treatment process to a certain extent.It improves not only the efficiency but also the effect of the livestock wastewater treatment.It provides a feasible scheme for the treatment of high concentration livestock wastewater,also offers a reference for similar problems,which has a certain significance for the practical application of livestock wastewater treatment process.