Experimental Study On Treatment Of Swine Anaerobic Wastewater In Micro-electrolytic And Anaerobic Bio-filter Process

With the development of the livestock industry, the pollution of which has been more serious these years, and the swine wastewater is the head of all pollution. Nowadays, the pool of firedamp has being in most of piggery, the swine wastewater has mostly been changed into anaerobic effluent by the pool of firedamp, and then been emitted directly. However, the anaerobic effluent still contains much of organic contamination and NH₄^--N etc., which brought about a huge press to the environment, and also made significant influence on the piggery's living and developing. So the further disposal to the anaerobic effluent has become an urgent affair to the disposal of swine wastewater. Moreover, though the anaerobic effluent is a kind of contamination, it's a sort of available resource. To this trait, the author work out a swine wastewater reborn and cycle system with the purpose of using its outing water in irrigation, which is more economic and more efficient contrast to the traditional ones.The micro-electrolytic and anaerobic bio-filter process was first applied to treat swine anaerobic wastewater in the light of the characteristics of its wastewater quality, which is hard to biodegrade and hard to disposal due to it contains high concentration of colloid. The filter medium of its reactor was the mixture of iron filings and carbon granules. In this reactor, it put the anaerobic bio-treatment and the iron-carbon micro-electrolysis process together, so as to make the jelly and organic contamination of the anaerobic effluent remove effectivelyFirstly, after captive test of micro-electrolysis, it is concluded that the optimal volume proportion of the iron and carbon in the bio-filter was 3:1; the HRT of the bio-filter should be controlled to 5 hours and above; only to see about the pH which is changed to 6 and unchanged. What's more, it also validated that it is resultful to improve the biodegradability of anaerobic effluent by this iron-carbon medium. The average ration of BOD5/COD of the anaerobic effluent has increased from 0.28 to 0.39 after 5 hours reacting, in the filter medium of which ration of its iron and carbon is 3:1.Secondly, to load the bio-filter with stuffing based on the conclusions of the captive test of micro-electrolysis, and then carried on its startup and running test. The startup of the bio-filter was completed within 29 days period under the operational conditions of influent COD concentration of 770mg/L, turbidity of 390NTU, pH=7.2～7.6 and HRT=12～18h. At the same time the filter medium retained the biomass successfully and the rate of turbidity removal reached 70% above. The startup results of study showed that the anaerobic bio-filter is characterized by fast startup, operation stable and effective treatment.In stable running phase of the filter, by seeing about the pH of entering water and HRT which has effect on the filter's stable running, and then concluded that: when pH of the entering water was change to 6 and what was unchanged, the difference of their processing effect were little, so that there is no need to change pH of the water but entering it directly. In addition, made a regressive analysis for HRT and rate of turbidity removal by software of SPSS, and then the regression equation was induced as follows: y=33.803+10.194x-0.538x², and the optimal HRT on filter's stable running was computed at 9.47 hours.Finally, the processing effect of the filter was tested by stable running test, and the results showed that the micro-electrolytic and anaerobic bio-filter could effectively remove the contamination of the swine anaerobic effluent, it could remove 80.81% of turbidity, 63.54% of COD and 48.81% of BOD. What's more, the BOD and COD of the effluent could meet the standards of pollutants for livestock and poultry breeding, and also accord with the standards of irrigation water quality for the dry farming.The paper put forward innovatively to using the micro-electrolytic process of iron and carbon to improve the biodegradability of anaerobic effluent, further to improve the anaerobic bio-treatment effect, and set up preliminary process for swine anaerobic effluent treatment, such as micro-electrolytic and anaerobic bio-filter process. The stuff of this process was made up of iron filings and carbon granules that had fallen into disuse in industry, and it formed a well treatment mode as "treating the waste by waste". The research method and conclusion have reference value for the further research and practice.