Surplus sludge production

Recently, anaerobic filter process has been widely used for the treatment of various waste-waters because of several advantages over aerobic process such as lower nutrient requirement, less surplus sludge production, and energy recovery via methane production [1]. Although many types of anaerobic filter process have already been successfully commercialized, the details of their complicated process dynamics are still challenging issues to be clarified for their stable operations. 

Small aeration tanks at the same F/M ratio and similar surplus sludge production as in CAS process... 

For acid treating of the diesel fuel and jet fuel products a "new" acid treater was designed and built, the major vessel of which were refinery surplus equipment. These vessels included a settler, clay contactor and sludge storage tank. 

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