Experimental Study On The Treatment Of Melon Food Processing Wastewater In Upflow Anaerobic Sludge Blanket (UASB) Reactors

The melon food processing wastewater mainly includes the cleaning wastewater, the dewatering of sectioning, grinding and cooking and the washing water of equipment and groud. Because the melon contains carbohydrates, dietary fibers, proteins, fat and various vitamins and amino acids, the melon dewatering has high organic concentration, if the wastewater drained directly without treatment, it will cause the serious water pollution. This experiment used the upflow anaerobic sludge blanket (UASB) reactor to degrade the melon food processing wastewater, in order to study the treatment effect of melon food processing wastewater by anaerobic granular sludge, master the operation parameters of the reactor.The results showed that the degradation of melon food processing wastewater with the UASB reactor in normal temperature obtains good results of treatment. The effluent COD could reach lower than 100 mg/L when the volumetric load of COD was about 6.0g/(L·d), meeting the standard of class 1 in Integrated Wastewater Discharge Standard (GB8978-1996). The COD removal rate could reach over 97% with the volumetric load of COD maintained 10.Og/(L·d). The melon food processing wastewater is weakly acid with the pH value of 4-6, it should regulate the pH when inlet water. Because the wastewater contains some proteins, the ammonia from the anaerobic decomposition of proteins can help maintain the basicity balance of the system in certain basicity, it can reduce the drug cost for regulating pH. In certain basicity, the effects of degradation were improved greatly with the pre-acidified wastewater. The effluent COD could maintain 100 mg/L-150 mg/L, the COD removal rate could reach over 98.6% with the volumetric load of COD maintained 10.Og/(L·d) when the influent pH value was 4.2-4.8. It showed that the degradation of melon food processing wastewater by anaerobic granular sludge is feasible.Start the UASB reactor again after stopped running for one month, after two weeks of time to run, the UASB volume loading and removal efficiency of organic matter has reached the level of initial startup, the effluent COD stabilized at 100-200 mg/L. The reactor runned well, the gas production increased with increasing organic loading, the COD removal efficiency remained above 97%. It showed that the study of dealing with melon food processing wastewater with the mature granular sludge to start the high-rate anaerobic reactor UASB is success, treating melon food processing wastewater with UASB reactor is feasible, not only can achieve a high degradation of organic pollutants, the second start can be successfully completed, and the operation can maintain stable.