Municipal and industrial wastewater treatment plants produce large amounts of sludge. This excess sludge is an inevitable drawback inherent to the waste activated sludge process. Both the reduction of the amount of sludge produced and improving its dewaterability are of paramount importance. Novel pre-treatment processes have been developed in order to improve sludge dewatering, handling and di...

The high moisture content of the excess sludge in sewage treatment plant has brought great difficulties to subsequent treatment. In this study, rice straw fiber was collected as a conditioner for adding sludge. effect different grain diameter and dosages on drying efficiency were investigated under temperatures. Drying temperature is one most important factors affecting rate. Compared with orig...

Excess sludge production is one of the limitations biological activated process. Therefore, study’s objective to upgrade MBBR process an integrated fixed film-activated (IFAS) reduce excess production. Two scenarios were followed in this study eliminate process: first, modifying moving bed biofilm reactor (MBBR) system by increasing solid retention time (SRT) from 5 15 days; and second, upgradi...

Seeding of nitrifying bacteria into the activated sludge process was studied both theoretically and experimentally. A simple model was developed for prediction of the effects of seeding of nitrifying bacteria from a separate stage into the activated sludge process. The purpose of seeding is to improve the treatment results and the process stability as well as to decrease the volume requirements...

Polyhydroxyalkanoates are known to be temporarily stored by microorganisms in activated sludge, especially in anaerobic-aerobic processes. Due to the problems resulted from the disposals of plastic wastes and excess sludge of wastewater treatment plants, the production of polyhydroxyalkanoates by treating activated sludge and determining the effect of process variables were the main issues of t...

Disintegration by hydrodynamic cavitation has a positive effect on the degree and rate of sludge anaerobic digestion. By applying hydrodynamic disintegration the lysis of cells occurs in minutes instead of days. The intracellular and extracellular components are set free and are immediately available for biological degradation which leads to an improvement of the subsequent anaerobic process. H...