Study On Anaerobic Digestion For High Strength Desizing Wastewater By UBF Reactor

Desizing wastewater is largely responsible for the chemical oxygen demand (COD) load in the textile industry wastewater. The traditional treatment for the textile industry wastewater with poor biodegradation such as poly vinyl alcohol(PVA) usually can't meet the wastewater discharge standard. The study on anaerobic digestion for high strength desizing wastewater by UBF reactor was conducted in this work, and the process parameters for both optimized process and operational control were put forward based on the detailed lab-scale research and analysis with respect to its startup of UBF, treatment capacity, opertional stability and control requirements.The startup of UBF reactor , the filter medium retained the biomass and the cultivation of active granular sludge adapt to desizing wastewater was completed within two months period. The startup results of study showed that UBF reactor is characterized by fast startup, operation stable and effective treatment capacity. Compared with the YDT filter medium and mixing filter medium found that mixing filter medium was very effective as a gas-liquid-solid separator and retained biomass better than YDT filter medium.The COD removal percentage of 56%~68% was observed under the operational conditions of temperture 35±2℃,OLR = 2.7-8.0 kgCOD/m3. d and HRT=9~24h. The stable COD removal of 64% and the production rate of CH4 was 0.25m3/m3.d could be maintained under the conditions of OLR = 4.4 kgCOD/m3. d and influent COD concentration of 4500mg/L.The results of study also indicated that the opertional stability of UBF reactor was effected of the ratio of B/C. The stable COD removal of 68% could be maintained under the conditions of OLR =13.1 kgCOD/m3. d and influent COD concentration of 5000mg/L at B/C=0.26, however The COD removal of 38% at B/C=0.15 under the same conditions. The ratio of influent COD/ SO42-≥2 and concentration of Cl <5. 3g/L can get high COD removal. It should adopted to no circumfluence method under pilot plant operation and low circumfluence rate(1~2) under full-scale plant operation in order to the uniformity of materiel on the section of UBF reacyor.The main anaerobic bacteria is bacillus and cocci and the average size of the granules was in the range of 2~3mm at the end of the stable period of UBF reactor.The parameters on the anaerobic kinetics can given by the theoretical analysis based on the results of stable period.