Background: A new biological domestic wastewater treatment process, which has been presented these days in activated sludge modification, is Upflow Sludge Blanket Filtration (USBF). This process is aerobic and acts by using a sludge blanket in the separator of sedimentation tank. All biological flocks and suspended solids, which are presented in the aeration basin, pas through this blanket. The performance of a single stage USBF process for treatment of domestic wastewater was studied in laboratory scale.Methods: The pilot of USBF has been made from fiberglass and the main electromechanical equipments consisted of an air compressor, a mixing device and two pumps for sludge return and wastewater injection. The wastewater samples used for the experiments were prepared synthetically to have qualitative characteristics similar to a typical domestic wastewater (COD= 277 mg/l, BOD5= 250 mg/l and TSS= 1 mg/l).Results: On the average, the treatment system was capable to remove 82.2% of the BOD5 and 85.7% of COD n 6 h hydraulic retention time (HRT). At 2 h HRT BOD and COD removal efficiencies dramatically reduced to 50% and 46.5%, respectively.Conclusion: Even by increasing the concentrations of pollutants to as high as 50%, the removal rates of all pollutants were remained similar to the HRT of 6 h.

In this study, the effect of antibiotic wastewater containing 20 common pharmaceuticals (14 antibiotics and 6 non-steroidal anti-inflammatory drugs (NSAIDs)) individually as well as their combination was investigated on activated sludge in batch reactors. The chemical oxygen demand (COD), the ammonium concentration, the inhibition rate and toxicity index of COD and ammonium were investigated in wastewater. The inhabitation for COD and ammonium removal was variable for each drug so that the pharmaceuticals are applied simultaneously had such a greater adverse effect on inhibition rate than individual compounds. The pretreatment of wastewaters containing drugs was performed by powdered activated carbon PAC to reduce the adverse effect of these drugs on activated sludge. The appropriate method for separation of PAC from wastewater before introducing to activated sludge process and the optimized adsorption and contact time during the pretreatment process were studied. The pretreatment of pharmaceuticals wastewater with activated carbon improved well COD and NH4 + removal to 71 % and 55 %, respectively, that demonstrate the activated carbon can be considered as a suitable pretreatment option for the activated sludge.

A simplified environmental biological model has been developed based on biodegradation kinetics correlation to regulate and optimize wastewater treatment system of activated sludge process. All parameters included in the model are calibrated in accordance with reference data and experimental results and good agreements are achieved between calculated results and reference data or experimental results. The minimum bioreactor volume is used as objective function in the model and errors between optimal minimum volume of the model and each reported result of three references are found to be no more than 8.63% after validation. Comparisons between optimal results and experimental data demonstrate that the deviations are negligible. The optimal minimum volume is 9.21 m3 with the error of 6.40% to the practical bioreactor volume of a pilot treatment system. The environmental biological model has been applied to economically evaluate a former treatment system with native bacterium YZ1 and four operation periods of the pilot system with functional strain Fhhh compared with YZ1, Fhhh possesses higher biodegradation ability in purified terephthalic acid wastewater and a broader economic potential in the field of wastewater treatment.

Semi-aerobic leachate is characterized by organic matter (COD, BOD) which is relatively low in concentration and difficult to biodegrade. In conventional treatment systems, the low biodegradability is attributed to partial stabilization of leachate at the landfill. Biological treatment of leachate in Malaysia is not well established and any important data for the treatment process is not available. The behavior of microbes is unknown for semi aerobic leachate. This research was conducted to establish some of the important data in the biological treatment of semi-aerobic leachate with and without the influence of powdered activated carbon (PAC). For the present study, semi aerobic leachate was collected from Pulau Burung Landfill Site (PBLS), Nibong Tebal, Penang, Malaysia. The experiment involved operating two 16 L laboratory-scale activated sludge reactors in parallel at room temperature and adjusted to pH of 6.5±0.5. One of the reactors was supplemented with powdered activated carbon (PAC) of 75-150μm size to observe its effect on leachate biodegradation. The results showed enhanced reactor performance due to PAC addition COD, NH4- N, NO3-N, TKN, BOD and colour removals was higher.

In Pakistan besides pesticide contamination from agricultural field, the manufacturing industries are also contributing relatively high quantities of toxic pesticides into the environment. These pesticides may be toxic, mutagenic or carginogenic and may be bioaccumulated or biomagnified by the biota. Because of persistent nature of pesticides, its removal from environmental system become difficult. The effective operation of wastewater treatment plant plays an important role in minimizing the release of toxic compounds into the environment. Research on the removal of toxic organics using the biological treatment plants is limited. In this study the bacterial isolate, IES-PS-1, was used to assess its potential for Cypermethrin degradation in activated sludge process. The experimental findings indicate that by maintaining the optimum operating conditions in the reactor, the removal efficiency significantly improved and>88% degradation observed at 80 mg/L dose. However, the complete removal of Cypermethrin, determined by High Performance Liquid Chromatography (HPLC), occurred at 20mg/L during 48 hour treatment. In addition, a considerable reduction in the sludge volume and chemical oxygen demand (COD) was also observed, producing an acceptable effluent quality with stable residual solids. These findings would be valuable in operating the wastewater treatment system for toxic waste removal.