Study On Treatm Ent Technology And Process Optim Ization Of Large-scale Swine Wastewater

In recent years,with the development of livestock industry.Waste water discharge is concentrated.This wastewater discharge,high concentrations of organic matter,high ammonia concentrations.However,aquaculture meager cost,wastewater is discharged without treatment depth.Discharge water quality is not up to standard.This phenomenon has resulted in breeding areas surrounding environment is severely polluted.In this paper,the effects of PAC,PFS and CP AM chemical flocculants on the treatment of swine farm wastewater were studied.Myriophyllum and biofilm were used as test materials to study the purification effect of aquatic plants and microbial membrane on swine farm wastewater under indoor static conditions.In the stage of Engineering application,aiming at the problem of poor treatment effect of SBR process for pig wastewater,this paper tries to add sodium acetate into SBR to improve the C/N ratio of wastewater,so as to strengthen the treatment capacity of SBR process.In addition,after the original wastewater treatment process,a four-stage series stabilization pond system is added to strengthen the treatment of the effluent of the original process in order to achieve the discharge standard.Experimental results show that:(1)PAC,PFS and CP AM all showed good removal effects on turbidity,COD and TP of pig wastewater,but the removal effects on NH4+-N and TN were not obvious.When turbidity is used as a measure to treat 1L pig farm biogas wastewater,the optimal dosage of 100 g·L-1 PAC,100 g·L-1 PFS and 5 g·L-1 CPAM is 14mL,20mL and 4.5mL,respectively.The removal efficiency of pollutants in wastewater is basically stable when the three flocculants are stationary for about 20 minutes,and the phenomenon of sediment floating will occur over a long time,which will affect the flocculation effect.PH value has a significant effect on the flocculation of pig farm biogas wastewater.However,the actual wastewater pH value is within a reasonable range,so it is not necessary to adjust the original wastewater pH value under normal circumstances.(2)In the experiment of using Myriophyllum +biofilm to treat the wastewater from pig farm biogas,the removal efficiency of COD in blank group,biofilm group,Myriophyllum group and Myriophyllum + biofilm group was not significantly different under the conditions of 80 mg·L-1 and 150 mg·L-1 of ammonia nitrogen concentration.The removal rate of COD in each group under 150 mg·L-1 of ammonia nitrogen concentration was higher than that of wastewater under 80 mg·L-1 of ammonia nitrogen concentration.The removal rate of ammonia nitrogen and total nitrogen in Myriophyllum +membrane group was the best when ammonia nitrogen concentration was 80 mg·L-1,which reached 92.51%and 82.49%respectively.The removal rate of ammonia nitrogen and total nitrogen in blank group was only 75.65%and 71.82%.Under the condition of 150 mg·L-1 ammonia nitrogen concentration,the removal rate of ammonia nitrogen in Myriophyllum+membrane group was 82.49%,the removal rate of total nitrogen was 65.33%,the removal rate of ammonia nitrogen and total nitrogen in the blank group with the lowest treatment effect was 71.82%and 50.64%,respectively.The removal rate of ammonia nitrogen in each group was higher than that in wastewater with the concentration of ammonia nitrogen at 150 mg·L-1 at 80 mg·L-1.Phosphorus was removed at both levels.Myriophyllum +Membrane group had the best effect on phosphorus removal,followed by plant group.(3)The removal rate of ammonia and nitrogen from pig wastewater biogas can be effectively improved by adding accelerated carbon source sodium acetate to SBR system.The removal rates of COD,ammonia nitrogen and total nitrogen increased from 16%±1%,25%±4%and 14%±1%to 32%±1%,55%±2%and 27%±4%respectively when the dosage of sodium acetate was 400 mg·L-1.The removal rates of COD,ammonia nitrogen and total nitrogen could be increased doubled.Although the pollutant effluent concentration of SBR has been reduced,it still can not meet the discharge requirements of "Standards for Discharging Pollutants from Livestock and Poultry Breeding Industry",and needs further treatment by subsequent processes.(4)Series stabilization pond process was used to intensify SBR effluent treatment.When the average influent concentration of COD,ammonia nitrogen,total nitrogen and total phosphorus were 450±10 mg·L-1,338±5 mg·L-1,406±5 mg·L-1 and 35 ±1 mg·L-1,the average removal rates of COD,ammonia nitrogen,total nitrogen and total phosphorus were 65 ± 2%,80 ± 4%,79 ± 3%and 83 ± 4%respectively.The effluent meets the discharge requirements of "Standard for Pollutants Discharge from Livestock and Poultry Breeding Industry"(GB 18596-2001);the first two stabilization pond systems consisting of biofilm and Paspalum distichu biceps contribute greatly to the reduction of COD,ammonia nitrogen,total nitrogen and total phosphorus in the effluent of SBR with high concentration,showing a high volume load.