Study Of The Treatment Of Sauce Wastewater With Expanded Granular Sludge Bed

Expanded granular sludge bed (abbreviated as EGSB) is one of the third generation anaerobic reactor developed by professor Lettinga on the basis of UASB. It increases the liquid surface upflow velocity in the reactor by circumfluencing the outfluent. Compared with the first and second generation of anaerobic reactor, EGSB reactor not only increases volume loading rate and operation efficiency greatly, but also has stronger stability and adaptabilty to bad conditions(such as toxic substances), so it is a effective new technology in wastewater treatment field.The EGSB reactor was started up by inoculating anaerobic granule sludge into EGSB reactor and cultivating with synthetic glucose wastewater under 35±1℃. The diameter of the cultivated granular sludge was even, and the average size was up to 1.4mm. Meantime, a study on the cultavition condition of anaerobic granule sludge was carried out and the results show that when the volume loading rate was 10 kgCOD/(m3·d), the circulation rate was 15, the liquid upflow velocity was 4.5m/h and the SS in the reactor was 45g/L, the sludge increased most quickly. After four or five days, the sludge concertration can increased up to 65g/L or so. The ration of quality and concentration of NaHCO3/COD of influent was 0.25-0.75, and COD and alkalinity in outfluent did not change much. The VFA concentration of EGSB outfluent increases with the decrease of NaHCO3, and when concentration of NaHCO3/COD was lower than 0.20, it means alkalinity was lower than 800mg/L, the treating system deteriorated and VFA increased quickly.Based opon the above research, a study on treatment of PTA wastewater with EGSB reactor was carrid out. The granular sludge cultivated by synthetic glucose wastewater was domesticated successfully after 35days of cultivation. And a good operation performance gained when the granular was used for PTA wastewater treatment. After 40 days'of stable operation, the removal rate of COD was up to 80 and the system had enough alkalinity and the volatile organic acid was basicly kept lower than 100mg/L. The effects of hydraulic retention time, liquid upflow velosity, influent COD and other parameters on the operation performances of the reactor were also studied. The results indicated that, the hydraulic retention time of PTA wastewater treatment with EGSB reactor were 16h, and the liquid upflow velocity were 3 to 5m/h, and since EGSB has a good ability of bearing shock loading rate, changes of influent COD didn't affect the operation efficiency much.At last, the effect of microelement on treatment of PTA wasterwater with EGSB reactor was researched. It was found that the efficiency can be greatly improved by adding microelement.