Development Of High Efficiency Compound Microorganism And Its Application In Black And Odorous Water Treatment

With the rapid development of China's social economy and the acceleration of the urbanization process,the discharge of industrial sewage and domestic sewage is constantly increasing,the sewage treatment collection and treatment system is not perfect and the waste water is discharged in disorder,resulting in the pollution of rivers,lakes and other water bodies,and even the black and smelly phenomenon of varying degrees.It has a serious impact on the sustainable development of China's economy and people's physical and mental health.Therefore,it is not only of great significance to explore the treatment methods of black and smelly water bodies,but also an urgent need for contemporary environmental protection.Aiming to improve the phenomenon of black and odorous water,this paper conducted a series of experiments.The main research results are as follows:(1)Explored removal effect of nitrosation XH6,bacterium bacillus subtilis KC2.0,candida JM13 and mixture liquid on CODcr and ammonia nitrogen in both artificial and natural black and odorous water and drew the following conclusion: order of removal rate of CODcr by size was : mixed bacteria liquid > candida JM13 > bacillus subtilis KC2.0 > nitrosation XH6 bacterium;removal rate of ammonia nitrogen by size was in the following order: mixed bacteria solution > nitrosoideonas XH6> bacillus subtilis KC2.0> candida JM13.It can be indicated that the mixed bacteria solution was more effective than single bacteria to remove CODcr and ammonia nitrogen in black odorous water.(2)Isolated and obtained 44 strains from enrichment solution of activated sludge and sediment of black and odorous water by using three separated medium.Conducted experiments of purification of black and odorous water with the 44 strains and selected five strains with good purification effect on artificial black odor water through primary and secondary screening,which are FX-4,FX-5,LB-3,LB-14 and ZX-7.The removal rate of five strains on CODcr and ammonia nitrogen in artificial black and odorous water reached 68% ~ 75% and 34% ~ 49% respectively.Identified that the five strains were respectively Nocardiopsis prasina,Streptomyces,Kocuria rhizophila,Acinetobacter johnsonii and Aspergillus versicolor through morphology observation and gene 16 S rDNA identification.It was found that aspergillus variegated was a pathogenic bacterium by literature review,which would easily cause ecological pollution if use for the treatment of black and odorous water.Therefore,it would not be considered as an alternative bacterial strain for microbial compound.(3)XH6,KC2.0,JM13,FX-4,FX-5,LB-3,and LB-14 were used to construct composite microbial agent.The strains were divided into three categories according to the medium: bacterium solution A,bacterium solution B and bacterium solution C.Fermentation performance and growth curve and of the three bacterium solutions were drawn.When the three bacterium solutions fermented 28 h,54h and 9d respectively,their microbial biomass reached the maximum and that was the best time for inoculation.Orthogonal experiment was conducted to determine the proportion of adding the three bacterial solutions in compound microbial agent.The experiment showed that degradation rate of CODcr was the highest with bacterial solution formula of A3B2C1,and the ammonia nitrogen removal rate was the highest with bacterial solution formula of A2B2C3.According to the verification test of the two bacterial liquid formulations,bacterial solution formula of A2B2C3 had the highest comprehensive degradation rate of pollutants,that is,when dosage of the three bacterial liquid reaches 1%,1% and 2% respectively,the removal effect on CODcr and ammonia nitrogen in the artificial black and odorous water is the best.(4)Identifying the best experiment condition of the compound microbial agents purifying black and ordros water was: speed of 200 r/min,pH of 6-9,dosage of microbial amount of 0.5%~1% and temperature of 25~30?.The artificial black odor water was purified under these experimental conditions,obtaining results that after 72 h,the degradation rate of CODcr reached 87.31%,and the ammonia nitrogen degradation rate reached 64.61% at maximum.Purifying natural black and ordors water under the same experiment conditions and got following results: after 96 h,the degradation rate of CODcr and ammonia nitrogen reached 71.22% and 46.63% respectively.(5)Combined biological treatment process of "aeration + compound bacteria agent" was employed to treat black and smelly river in a tributary of Lulei River.The control group only operated aeration system without adding bacterial agent.After the aeration system was put into operation,the dissolved oxygen was restored from 0.2mg/l to 5mg/l.After 14 days of system operation,the degree of black and odor of water significantly declined: amount of CODcr of the experimental group was reduced to 40mg/l or so,and removal rate on CODcr reached 70-75%.Amount of CODcr of the control group was about 85mg/l stably,and removal rate on CODcr was about 40%.Ammonia nitrogen in the control group was finally stabilized at 15mg/l,and removal rate on ammonia nitrogen was only 30%.Ammonia nitrogen in the experimental group was reduced to about 4mg/l,and the removal rate on ammonia nitrogen reached 85.13%.ORP of the control group was restored to about 50 mV,while ORP of the experimental group was increased to more than 100 mV after stabilization.The transparency of the experimental group reached 33.7cm,while that of the control group only recovered to 15 cm.The results showed that ammonia nitrogen,ORP and transparency of the aerated control group were not up to the standard,and black and odor in water was not completely removed.While the water quality of the experimental group has reached the standard,the black and odor being completely removed,the number of aerobes in the water increasing significantly,and the water ecology restoring gradually.