ACTIVATED sludge processes are the dominating wastewater treatment method. Large quantities of hazardous excess sludge are generated in the processes, and elimination of the waste sludge has been a major problem for the last decade worldwide. The disposal of waste sludge is subject to various environmental, social and economic problems; and the cost consists about 50% of the operational cost of...

Bulking of activated sludge is a world-wide problem which negatively affects wastewater treatment efficiency. The most common reasons of bulking are bacterial community changes, especially excessive growth of filamentous bacteria (filamentous bulking) or excess of biopolymers on the surface of non-filamentous microbes (non-filamentous or Zoogleal bulking). Because of the complex nature of the b...

The removal of Total and Volatile Suspended Solids (TSS/VSS) was studied in a pilot-scale UASB (Upflow Anaerobic Sludge Bed) reactor treating settled sewage under subtropical conditions (Salta, Argentina). The effect of sludge bed height (hsb) and upflow velocity (Vup) on the removal of TSS and VSS was assessed. TSS and VSS removal efficiencies of up to 95% have been achieved when Vup ≤ 0.43 m/...

A mesocosm experiment to assess the fate and effects of sewage sludge in the coastal marine environment was conducted over 4 mo during the summer of 1984 with 9 different treatments of sewage sludge and nutrient addtions. Evidence from setthng rate studes, accumulahons of carbon and pollutant organics and rahos of in the sediment indicated up to 83 O/O of the sludge particulate inputs settled t...

To remove the excess nitrogen and phosphorus in swine wastewater, an electrodialysis technique was applied to an advanced treatment method. The laboratory-scale swine wastewater treatment system constructed for the present study consisted of an activated sludge process, as the main treatment unit, and electrodialysis, as an advanced treatment unit. This system was operated for 200 days and the ...