Preparation Of Compound Bacteria Agent For Ammonia Degradation And Its Effect Analysis In Purifying Aquaculture Wastewater

Nowadays, intensification of aquaculture have been adopted in many countries and as a response to food safety and especially the reduction in ocean fish resources. But this culture model is still facing many problems,such as aquaculture environmental pollution, it will reduce the oxygen content of the culture water, cause many diseases, resulting in germplasm degradation of aquatic animals. Therefore, to protect aquatic ecosystems, and maintain the good germplasm resources is the only way to improve the efficiency of aquaculture and keep it's healthy.Ammonia is one of the major contaminants in aquaculture, a little of ammonia is benefits to the growth of aquatic organisms, but an excess of ammonia will cause deterioration of water quality, which can cause animals death and other phenomenon. Compared with the physical and chemical methods, the biological nitrogen removal has many advantages. It has more efficiency, safety, and will not increase the burden on the environment. In this study, we used conventional methods to isolate and purify microorganism from the marine sediments, named 7-7, 5-4, 683 which nitrogen removal efficiency was 70% — 90%.Through morphological, physiological, biochemical and genetic level of determination, we found the 7-7 is highest homology with Marinobacter maritimus, the similarity rate is 97%. 5-4 is highest homology with Arthrobacter mysorens,the similarity rate is 99%. 683 is highest homology with Bacillus firmus, the similarity rate is 99%.By UV spectrophotometry, 1-naphthyl for- diethylamine hydrochloride salt spectrophotometry, nessler reagent spectrophotometric determination of the types and removal of nitrogen removal,we found that7-7 could decompose nitrate and nitrite,the removal rates were 90 % and 86 %, 683 can break down nitrate and the removal rate was 86 %,5-4 can resolve ammonia and the removal rate was 84 %.Study about the growth characteristic, the results showed that the optimum temperature of the three bacteria at 20?-30?, the optimum temperature of 683 at 20?, the temperature of 7-7 and 5-4 at 28?, but they also observed high nitrogen removal efficiency under 20?. So they were suitable for mariculture environment. The optimum p H of three strains were alkaline and its carbon source was sodiumcitratThrough composite culture, and determines the final composite ratio is 2: 2: 3. After optimizing the ratio of composite bacteria,the removal rates of ammoni nitrogen, nitrate nitrogen, nitrite nitrogen are improved, the removal rates were 94 %, 89 %, 87%.Immobilization of bacterial consortia on activated carbon carrier, expanding culture, made up agent, under laboratory conditions, is applied to the man-made aquaculture wastewater, nitrate,nitrite and ammonia degradation rate is 91 %, 87 %, 84 %.