Study On Purifying The Aquacultural Waste Water With Immobilized Bacteria-alga System

The industry of aquaculture has been developing rapidly in recently. Great deal of aquaculture waste water was produced and entered the environment with bad effects.These methods can remove suspended particles effectively but can not reduce the concentration of solvable matters.The research object of the paper is the aquaculture flesh waste water.The goal is that we will prepare one kind of immobilized microorganism beads, which could purify the waste water.The immobilized preparation method needs to be simply,the price needs to be inexpensive,and to be not poisonous for animals in the waste water.When we put the immobilized microorganism beads into the waste water,it cannot bring give birth to the effect of secondary pollution.Eventually,we want to provide an effectual method for purifing the aquaculture fresh waste water.The main results were summarized as follows:1.By experimental verification,among these microoganism(nitrifying bacteria,Bacillus licheniformis,Bacillus subtilis,Photosynthetic Bacteria, Scenedesmus quadricauda,Chlorella pyrenoidosa,Selenastrum reinsch, Anabaena spiroides),nitrifying bacteria,Bacillus licheniformis,Scenedesmus quadricauda,Selenastrum reinsch could effectively remove nitrogen, phosphorus and orginic compounds.When putting the mixture of the four microoganism,they could give birth to the effect of complementary advantages.2.The optimum microorganism ratio of Bacillus licheniformis,nitrifying bacteria,Selenastrum reinsch,Scenedesmus quadricauda was established according to the orthogonal test design.The volume ratio is 1:2:2:2 since the quantity of microorganism is 2x10⁶ cfu/mL.The rate of the optimum microorganism system to remove COD_cr,NH₄⁺-N,NO₂^--N,NO₃^--N and dissoloved phosphorus was 44.05%,89.16%,100%,98.62%,100%respectively. Through the test proved,water quality of groups added bacteria and algae was batter than the blank.Based on the range analysis of all the factors in the system,we could come to a conclusion that Bacillus licheniformi is the key factor of removing COD_cr and NO₃^--N.Scenedesmus quadricauda plays an important role in removing ammonia nitrogen,Selenastrum reinsch shows very significant function to nitrite nitrogen,and nitrifying bacteria could remove dissoloved phosphorus very well.3.Eventually,we use PVA-H₃BO₃ for embeing the mixture of bacterium-alga.After immobilitied,the effect of depurating the waste water is better than the suspended,if we append some active carbon into the mixture before immobilitied,the effect will be better.