results the results of this study showed that the release of soluble chemical oxygen demand (scod) in the supernatant and srf were in the range of 127.9-831 mg/l and 12.48-36.55 m/kg at 10 to 120 min ultrasonic contact time, respectively. in addition, ts and vs decreased from 57.98 and 56.31 to 52.69 and 49.87 mg/l, respectively. despite the significant reduction in the solids, there was no con...

Sludge deposition in the environment is carried out in several countries. It encompasses the dispersion of treated or untreated sludge in forests, marsh lands, open waters as well as estuarine systems resulting in the gradual accumulation of toxins and persistent organic compounds in the environment. Studies on the life cycle of compounds from sludge deposition and the consequences of depositio...

Mixed-microbial assemblages enriched from a septic tank, coastal sediment samples, the digester sludge of a brewery wastewater treatment plant and acidic sulfate soil samples were compared on the basis of growth rate, waste and sulfate reduction rate under sulfate reducing conditions at 30 degrees C. The specific growth rate of various cultures was in the range 0.0013-0.0022 hr(-1). Estimates o...

most of the water treatment plants in iran discharge their sludge to the environment whithout consideration of possible side effects. since this kind of sludge is generally considered pollutant, the sludge treatment of water industry seems to be an essential task. obviously theweight and volume of solids produced during the coagulation process are much more than other wastes of water treatment ...

Heavy metals (HMs) immobilization in sewage sludge was investigated by using subcritical water technology (SCWT) in this study. The characteristics of sludge and toxicity of HMs were analyzed after SCWT process. The results showed that besides large reduction in sludge volume, SCWT had some positive effect on HMs dissolution into liquid phase, while the majority of HMs was still accumulated in ...

One of the main challenges for one phase anaerobic digestion processes is the high concentration of NH4 and PO4 ions in the digested sludge supernatant. This project focuses on enhancing the removal of nutrients during the anaerobic digestion process through fixing both NH4 and PO4 ions in the form of struvite (magnesium ammonium phosphate, MAP, MgNH4PO4.6H2O) within the anaerobic sludge. Batch...

Tubificidae is often used in the wastewater treatment systems to minimize the sludge production because it can be fed on the activated sludge. The process conditions have effect on the growth, reproduction, and sludge reduction efficiency of Tubificidae. The effects of the water quality, density of worms, pH, temperature and dissolved oxygen (DO) concentration on the respiration rate of Tubific...