| Biological pesticide S-resistance element (abscisic acid, ABA) is internationally recognized as one of the five plant endogenous growth regulating substance. It is a type of high efficient growth substance and widely applied to cultivation of crops, such as vegetables, flowers, cotton, tobacco and soybean. The wastewater belongs to one typical refractory organic wastewater, containing alcohols, fatty acids, esters and other volatile substances. Comprehensive control method (air) was carried out on the extraction wastewater pretreatment.Based on a series of system research methods, the treatment of high concentration organic wastewater produced during S-resistance element production was studied. A set of perfect, practical and high efficiency low cost processing technology were established after laboratory biological treatment process, microbiology diversity and pilot exploration. The main conclusions are as follows:Through pretreatment, CODcr content and sulfate content were reduced by 23.7%and 98.8%, respectively. Then, the wastewater was treatment by UASB reactor forming granular sludge and two stage aerobic biological contact oxidation pool, orderly. The best operating conditions of UASB were determined as follows:HRT for 24h, operating temperature of 35℃, alkalinity between 1000-1200mg/L, pH for 7-8, UASB volume load of 6.0kgCODcr/(m3·d), and the CODcr removal rate is about 90%. The optimization conditions of first contact oxidation reactor were follows:pH 7.0-8.0, operating temperature 20℃, HRT 32h, DO 2mg/L. And the optimization conditions of second contact oxidation reactor were follows:HRT 20h, DO 2-4mg/L. Under the optimization conditions, the CODcr of effluent was below 100mg/L.20 strains were isolated from treatment reactors.15 strains of microorganisms was isolated from UASB, including 8 strains of aerobic bacteria,5 strains of anaerobic bacteria and 2 strains of methanogens; 5 aerobic bacteria were isolated from contact oxidation reactor. The 16S rRNA sequence analysis shows that the aerobic bacteria (AE1-AE8) isolated from UASB were most similar with Pseudomas aeruginosa, Leclerica adecarboxylata, Proteus FFL13, Strptomyces sp.3083, Citrobacter amalonaticus, Thauera aminoaromatica, Vagococcus penaei CD 276 and Enterococcus asini AS2, respectively. The anaerobic bacteria (AN1-AN5) were most similar with Clostridium lituseburenese, Clostridium irregulare, Clostridium glycolicum, Eubacterium fissicatena DSM 3598 and Acidaminococcus fermentans DSM20731, respectively. Methanogens ME1 and ME2 were closest to Methanospirillum hungatei JF-1 and Methanococcus mazei, respectively. The 5 strains isolated from contact oxidation reactor, were closest to Pseudoxanthomonas mexicana AMX26b, Acidovorax caeni R-24608, Zoogloea ramigera 106, Leptothrix discophora SS-1, Comamonas sp. R-25060, respectively.Isolation physiological characteristics analysis showed that different strains have different metabolic activity. S-resistance as the main product of fermentation, could be degradated by most of the bacteria. The other metabolic activities of bacteria isolated from the UASB reactor were follows:strain AE1 and AE8 could metabolize most of the substrate whose carbon atoms number was greater than 4, AE3 and AE4 use the substrate with carbon atoms number greater than 6, strain AE5, AE6 and AE7 metabolized fatty acid of carbon atom number between 4-8,6-9 and 4-7,respectively; Anaerobic bacteria strains AN1 metabolized 2-methyl-butyric acid and the substrate of larger molecular weight, strain AN2 metabolized octylic acid and larger molecular weight pollutant, AN3, AN4, AN5 could utilize acid and larger molecular weight contaminants; Strain ME1 was H2+CO2 type methanogens, ME2 was acetic acid type methanogens. Separated strains had the metabolic activity in the contact oxidation pool characteristics:all the strains made use of S-resistance, strain BE1 metabolized heptanoic acid and 4-methyl-phenol, strain BE2 and BE4 utilized hexanoic acid and heptanoic acid, strain BE3 metabolized heptanoic acid and 4-methyl-phenol, strain BE5 utilized acetic acid, hexanoic acid and heptanoic acid.The microbial population structure and diversity of bacteria in UASB reactor and archaea were analysed with 16S rRNA technology. The result showed a rich microbial diversity in UASB reactor and the bacterial diversity was more abundant than archaea. Bacteria clone library has been determined in article 161 of the 16S rRNA sequences belong to 18 genotypes, and the archaea clone library has been determined in article 81 of the 16S rRNA sequence belongs to five genotypes. Clostridia was the absolute advantage bacteria group, and the other advantages of bacteria were Bacilli, Gammaproteobacteria, Betaproteobacteria and Methanobacteria.The microbial diversity of contact oxidation reactor was studied using 16S rRNA and 18S rRNA technology. Results showed a rich microbial diversity in contact oxidation reactor. The bacterial diversity was more abundant than fungal diversity.192 of bacterial clones and 74 of fungal clones were belong to 29 bacteria genotypes and 6 fungal genotypes, in bacterial and fungal sequence library respectively. Betaproteobacteria in aerobic contact oxidation pool was absolute advantage bacterium group, and other advantage bacterium groups were Alphaproteobacteria, Gammaproteobacteria, Microbotryomycetidae, Tremellomycetidae and Peritrichia.Pilot study showed that the biochemical treatment of this wastewater was feasible. Biofilm growth was good, and the microorganism domestication was successful; Biochemical treatment system worked well, and the CODcr removal rate was higher than 99%. The results of GC-MS analysis indicated that there had only trace amounts of acetic acid and propionic acid in effluent. |
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