Research On New Technology Of Biological Nitrogen And Phosphors Rmoval In Full-Scale Swine Wastewater

Swine wastewater is a typical livestock and poultry of high organic concentration wastewater, biogas slurry (or anaerobic digestion) which come from biogas project, a widely used treatment of swine wastewater, is hard to be treat and disposed, especially the problem of effluent nitrogen and phosphorus in the full-scale biogas slurry can not reach standards which is more and more serious。The treatment of biogas slurry becomes the research focus of the water pollution control and water quality protection technology. Based on the results of laboratory research on swine wastewater, the demonstration project of SBBR(Sequencing Batch Biofilm Reactor) carried out to purify biogas slurry with an optimization study, the main conclusions are:(1) The biogas slurry was a typical low C/N (0.99) and low C/P (7.07) wastewater, it could not get a good treatment effect by a single aerobic or anaerobic type of nutrient removal technology directly treatment, such as SBBR, and effluent was hard to reach standards(2) The result of optimized operation in demonstration project proved that the method of adding additional carbon sources with 30% pig raw water was feasible for the optimized treatment of the biogas slurry The removal rates of COD, NH3-N and TP in optimized biogas slurry could be increased to 70%,83%, and 68% respectively, and the effluent average concentration of COD, NH3-N, TP in SBBR of demonstration project could be reduced to 220mg/L,53mg/L, and 13 mg/L.(3) The C/N and C/P of optimized biogas slurry in demonstration project had been improved to 3.0 and 18.3 respectively, adding with 30% pig raw water could radically improve the biodegradability of biogas slurry and promote denitrification, which finally could reduce 60% of nitrite accumulation and can make TN removal rate increased to 62.8%.Effluent of SBBR in demonstration project still further treatment for the litter higher concentration of TP, while the traditional relatively independence of the nitrogen and phosphorus removal can't reach integrated and efficient treatment effect.In order to achieve organic integration of nitrogen and phosphorus removal in nutrient removal of swine wastewater, this topic carried out experiment on denitrifying phosphorus removal and release of phosphine for swine wastewater to provide basis data for further project of new nutrient removal technology in swine wastewater. The experiment studied on new nutrient removal technology of swine wastewater concluded that:(1) Because C/P ratio of was low, the effect of phosphorus removal in simulated directly biogas slurry treatment by A2NSBR was bad, the removal rates of TP removal was only 53%, biogas slurry could not achieve good denitrifying phosphorus removal.(2) The increase of influent concentration and the C/P ratio was beneficial to improve denitrifying phosphorus removal capabilities of A2NSBR, when influent COD concentration increased to 700mg/L, the removal rate of TP increased to 78% in simulated wastewater by A2NSBR. Therefore, the actual biogas slurry still needs to adjust its water quality, increased C/P to get good denitrifying phosphorus removal.(3) Release of phosphine in pig raw water and biogas slurry could reach 0.048mg/h and 0.033mg/h respectively, and generated concentration were 9.6mg/m3 and 6.6mg/m3 respectively, which were 2-3 orders of magnitude higher than the maximum concentration reported in the literature, phosphine had a great potential in phosphorus removal of swine wastewater.(4) Study on phosphine release in different concentrations of swine wastewater figured out:concentrations of COD and phosphine release yield had a good positive correlation with a correlation coefficient of 0.88, the relevant equation was: y(PH3,mg)=0.02866+0.00016x(COD,mg/L); concentrations of TP and phosphine release yield also showed some positive correlation, which indicated that the increase concentrations of COD and TP could enhance the phosphorous reduction of microorganisms and was conducive to the generation of phosphine; increase of NO3-would suppress the production of phosphine, which to some extent showed the inhibition of NO3- on phosphorous reduction, that might be due to the reduction of NO3-and phosphorus had a competitive relationship on the electron donor.