the aim of this work was to optimize the coagulation-flocculation (cf) process applied tomunicipal wastewaters (ww). optimization of cf was performed to minimize chemical oxygen demand(cod), turbidity, sludge produced, and some metals in sludge. a box-behnken design was used to evaluate the effects and interactions of three factors such as type of biopolymer (guar, mesquite seed gum and opuntia...

Phenol and it derivatives are considered as one of the priority pollutants in waste water, because they are harmful to organisms even at very low concentrations. The control as well as removal of these organic compounds has become an important issue due to stringent measures introduced by various countries to enforce regulations concerning wastes originating from various industries. Hence, wast...

A 5-day Biological Oxygen Demand (BOD5) is one of the parameters which are used to determine the amount of biodegradable organic substances in water environments. In dimensioning wastewater treatment plants, BOD5 is used for determining organic loading rates which enter the wastewater treatment plant and affect such parameters as surplus sludge production and oxygen demand. Conventional “static...

The adsorption of trace contaminants on natural particles is of great interest as this adsorption enhances the possibility of removing these with low pressure filtration such as MF and UF. This study shows that natural hormones such as estrone and estradiol will adsorb to natural particles both organic and inorganic. Experiments have shown that the adsorption capacity of organics is a factor of...

Although the activated sludge process for stabilizing liquid organic wastes is primarily a biological process, very little research has been conducted on the pure biological phases of this process. Until the work of Butterfield (1935), activated sludge was considered by some as a physio-chemical process and by others as a bio-chemical process. Butterfield isolated a bacterium, Zoogloea ramigera...

Sewage sludge-amended soils may alter their ability to adsorb heavy metals over time, due to the decomposition of sludge-borne organic matter. Thus, we studied Cd, Ni, and Zn adsorption by a sewage sludge-amended soil (Typic Xerofluvent) before and after one-year incubation in both monometal and competitive systems. In the monometal system, the order of decreasing sorption was Zn>Cd>Ni. Competi...

Earthworms feed readily upon sludge components, rapidly converting them into vermicompost, reduce the pathogens to safe levels and ingest the heavy metals. Volume is significantly reduced from 1 m³ of wet sludge (80% moisture) to 0.5 m³ of vermicompost (30% moisture). Earthworms have real potential both to increase the rate of aerobic decomposition and composting of organic matter and also to s...

Although activated sludge communities are considered stable, the presence of toxic substances, such as Cr(VI), in the influent may induce changes in the activity and the performance of a wastewater treatment plant. The main objective of this study was the determination of Cr(VI) effects on the performance and on the protistan community of an activated sludge. Six laboratory scale activated slud...