Analysis On Key Factors Of The Formation Of Black And Odor In The Water Body And Experimental Research On Purification

Black and odorous water pollution will not only cause harm to human health,but also seriously pollute the environment and damage the image of the city.It is urgent to develop an environmentally friendly,economical and efficient treatment method.In this paper,taking the black and odorous water body of a channel in an urban-rural junction in a certain place in Hunan as the research object,through the analysis of the black and odor-causing factors of simulated water samples,and on the basis of determining its key influencing factors,a technical route of“H₂O₂ preoxidation-adsorption-coagulation sedimentation”was designed,and prepared a new type of activated sludge immobilized compound bacterial agent,which has achieved good repair effect on the black and odor synergistic treatment of water body.The specific research contents are as follows:（1）Six water quality conditions,including total organic carbon（TOC）,total nitrogen（TN）,total phosphorus（TP）,sediment content,Fe²⁺concentration and Mn²⁺concentration,which affect the black and odorous water body,were formulated,and single-factor experimental analysis was carried out,and determine the key factors of black and odor caused by water body through orthogonal experiments.It is found that the primary and secondary degrees of influence on the formation of black odor in water are:TOC>TN>Fe²⁺>TP,in which the total organic carbon content is the key factor for black odor in water;when the water is at TOC=200 mg/L,TN=30 mg/L,TP=75 mg/L,Fe²⁺concentration=20 mg/L water quality conditions,the most likely to cause black odor phenomenon.（2）5 kinds of water purifiers were selected for the formulation design of black and odor removal in water,respectively:slow-release oxygen agent/oxidant-hydrogen peroxide;coagulant-PAC,diatomaceous earth;adsorbent-4A molecular sieve,artificial zeolite.The formulation of PAC,hydrogen peroxide and artificial zeolite was determined by single-factor drug comparison experiment,and the appropriate dosage was:PAC 150 mg/L,hydrogen peroxide 15 m L,and artificial zeolite 300 mg/L.The redox potential of the treated water samples increased by 185.23%,the turbidity removal rate was 91.30%,and the total phosphorus removal rate was 99.36%.Using this formula to conduct a river simulation experiment,it was found that after 7 days of treatment,the turbidity was reduced by 71.54%,and the total phosphorus content was reduced by 96.52%,achieving a good black and odor removal effect.（3）The immobilized activated sludge composite inoculum with graphene oxide,polyvinyl alcohol,and sodium alginate（GO+PVA+SA）as the carrier was prepared by sludge acclimation and microbial immobilization technology.The suitable experimental environment for the bacterial agent is the temperature of 25℃,p H=7～8,and rotation speed=100～200r/min.After 10 days of treatment with immobilized bacterial agent+bottom aeration,the water sample changed from turbid and black to clear and transparent,the amount of dissolved oxygen was significantly increased by 46.94%,and the total phosphorus and ammonia nitrogen were greatly reduced by 89.05%and 93.39%respectively.The effect of synergistic control of black and odor in the water body.（4）The microstructure SEM analysis of the immobilized composite bacterial agent showed that the surface of the immobilized carrier with added graphene oxide showed a certain wrinkled lamellar structure,which could provide attachment sites for the activated sludge bacteria micelles,indicating that the embedding effect of the immobilized materia was good.The GC-MS analysis of the water samples after biochemical treatment of the immobilized compound bacterial agent found that the key odor-causing components（geosmin,2-methylisocamphenol,2-methoxy-3-isobutylpyrazine）were effectively eliminated.