The present disposal routes of sewage sludge represent a critical environmental issue in Egypt. Recently, there has been an increasing concern about sewage sludge management due to the environmental risks, which resulted from the fast expansion of wastewater treatment plants without equal attention in dealing with the produced sludge. This paper discusses the current situation of sewage sludge ...

The co-disposal of densified sludge and wastepaper in a co-current flow packed bed gasifier represents new application of the thermal gasification process. Advantages of this technolo a gy include lower costs than other incineration or pyrolysis technologies, simple construction and operation, and the ability to a variety of fuels including agricultural wastes and other b.iomass materials in ad...

Wastewater treatment produces solid residuals. Land application provides a sustainable, beneficial alternative for solids disposal, but it increases the threat of public exposure to disease. As such, regulatory agencies in many countries limit the number of pathogens allowable in residuals. One of the most common and resistant pathogens is the egg of the intestinal parasitic worm, Ascaris. Alka...

This paper presents three new approaches to reduce excess sludge production in activated sludge systems: 1) modification of conventional activated sludge process with insertion of a sludge holding tank in the sludge return line; 2) chlorination of excess sludge so as to minimize excess sludge production; and 3) utilization of a metabolic uncoupler, 3, 3', 4', 5-Tetrachlorosalicylanilide (TCS) t...

Biological wastewater treatment processes under a dynamic regime with respect to carbon substrate can result in microbial storage of internal polymers (e.g., polyhydroxybutyrate (PHB)) and their subsequent utilizations. These storage turnovers play important roles in nitrous oxide (N2O) accumulation during heterotrophic denitrification in biological wastewater treatment. In this work, a mathema...

An in situ respirometric technique was applied to a sequential biofilm batch reactor treating a synthetic wastewater containing acetate. In this reactor, inoculated with mixed liquor from a wastewater plant, unglazed ceramic tiles were used as support media while maintaining complete mixing regime. A total of 8 kinetic and stoichiometric parameters were determined by in situ pulse respirometry;...

Alternate cycling of sludge in aerobic, anoxic, and anaerobic regimes is a promising strategy that can reduce the sludge yield of conventional activated sludge (CAS) by up to 50% with potentially lower capital and operating cost than physical- and/or chemical-based sludge minimisation techniques. The mechanisms responsible for reducing sludge yield include alterations to cellular metabolism and...

The literature on reduction of excess sludge production by ozonation is summarized. Two sequencing batch reactor experiments where sludge is ozonated for this purpose are performed. The purpose of these is to evaluate the prospects of using ozonation to reduce excess sludge production in two different kinds of sludge. Urban sewage sludge is used in the first, and paper mill sludge in the second...

The coking process produces great volumes of wastewater contaminated with pollutants such as cyanides, sulfides and phenolics. Chemical and physical remediation of this wastewater removes the majority of these pollutants; however, these processes do not remove phenol and thiocyanate. The removal of these compounds has been effected during bioremediation with activated sludge containing a comple...