Experimental Study Of Improved UASB Reactor Treatment Of Organic Wastewater

The anaerobic treatment process can be considered as the core method of a resource preservation and environmental protection technology, it is a sustainable and appropriate wastewater treatment technology in China. A new Improved-UASB was designed based on the engineering practice, is development and improvement for the traditional UASB. Operational characteristics of the experimental reactor were studied in the test, the main results were abtained as follows:The start-up and operational characters of Improved-UASB were discussed systematically. The experimental results indicated that the start-up of the reactor can be completed in 17 days. When the volume loading rate and COD of influent were 8.2kgCOD/(m3-d),4000-5000mg/L, the COD removal rate was still above 90% respectively. When volume loading rate was increased to 9.76kgCOD/(m3-d), severe acidification took place in the reactor and COD removal rate dropped significantly.The effects of influence factor such as volume loading rate, pH value, alkalinity and the upflow velocity of liquid surface on the treatment performance were also studied, and the experimental results indicated that COD removal reduced temporarily at the beginning of increasing volume loading rate, and 400-1000mg/L of influent alkalinity was enough for high COD removal rate. When the volume loading rate, HRT and COD of influent were 8.5kgCOD/(m3·d),7.85h and 4000-5000mg/L, the upflow velocity of liquid surface was optimized to 4m/h, the COD removal rate was up to 95.6%, and the VFA was 47mg/Llow.The variation of COD, pH value, alkalinity and SS along the reactor height were investigated. It indicated that the operational characteristics of reactor were between plug flow and complete mix. The sludge bed was expanded sufficiently, when the upflow velocity of liquid surface was 4m/h, the effect of mixing among the sludge and the substrate was up to the best.Physical characteristics of granular sludge were also investigated. The experimental results indicated that the larger the granular size is, the more rapid the granular settle. It was founded that the settling velocity of granular from different samples were close to theoretical values.