ACTIVATED SLUDGE PROCESS is one of the well-establish methods for biological treatment of oily wastewater, which use in Iranian oil refineries. However, the PROCESS involved many problems such as low efficiency at high concentration of hydrocarbon, instability during hydraulics shocks and bulking phenomena. In this paper attached and suspended growth was used to improve conventional ACTIVATED SLUDGE treatment PROCESS. A hybrid ACTIVATED SLUDGE reactor, with 34.5 liter capacity, was used in order to treat synthetic high CODs oily wastewater and the results were compared with those obtained from conventional ACTIVATED SLUDGE reactor. Novel media used in this fixed-film biofilm bioreactor, provided a high surface area-to-volume ratio (600m2/m3). Reactor biodegradability for COD and TPH was evaluated for different hydraulic retention time (HRT) and oil pollution concentration. In optimum condition (T= 27oC, pH= 7.5, DO= 4.1mg/l, recycle SLUDGE ratio= 1 and COD/TPH= 2.5) the removal efficiency of HASBR for TPH and COD were 90% and over 95% respectively which showed a significant difference in comparison with the conventional ACTIVATED SLUDGE reactor in the same conditions. Therefore, existing conventional ACTIVATED SLUDGE plants could be upgraded and improved by changing the reactor configuration and introducing support media into aeration tank.

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.

Backgrounds and Objectives: Direct biodegradation of landfill leachate is too difficult because of high concentrations of COD and NH3 and also the presence of toxic compounds. The main objective of this study was to application of Strurvite precipitation as a pretreatment stage, in order to remove inhibitors of biodegradation before the batch decant ACTIVATED SLUDGE PROCESS with addition of powdered ACTIVATED carbon (PAC).Materials and Methods: Strurvite precipitated leachate was introduced to a bench scale batch decant ACTIVATED SLUDGE reactor with hydraulic retention times of 6 and 12 hour. PAC was added to aeration tank directly at the rate of 3.5 g/L.Results: TCOD, SCOD, NH3 and P removal efficiency with addition of PAC in HRT of 6 h were 90, 87, 98.3 and 94 % respectively and 96, 95, 99.2 and 98.7 5 in HRT of 12 h.Conclusion: According to obtained data from this work, it can be concluded that Strurvite precipitation before batch decant ACTIVATED SLUDGE PROCESS and simultaneous addition of PAC is promising technology for leachate treatment and can meet effluent standards for discharge to the receiving waters.

Background: Using the SLUDGE as fertilizer on farms is one of the options to dispose it, which due to its variety of pathogenic microorganisms, it may cause a wide range of bacterial and parasitic diseases in human and livestock. The purpose of this study is to investigate the feasibility of using dried SLUDGE produced in municipal wastewater treatment PROCESSes to fertilize agricultural lands in accordance to the health and environmental standards.Methods: In this analytical-descriptive study, three sewage treatment plants of Chahar Mahal and bakhtiary province were selected as the sample plant, including Shahrekord, Farsan and Borujen due to their similarity in the weather condition and the treatment PROCESS. In order to investigate the SLUDGE in its lowest and the highest rate of evaporation, in the freezing cold winter and burning hot summer respectively, two winters and two summers were selected as the timeframe. In this study, faecal coliform and total coliform were determined as the SLUDGE microbial indexes and examined in accordance to the EPA standards.Findings: The findings of this study indicated that the mean value of faecal coliform for the three treatment plants in winter were 1.63 × 106, 1.93 × 106 and 1.98 × 106 respectively. Also in summer they were 4.51 × 106, 5.75 × 106, and 9.23 × 106 respectively.Conclusion: The evaluations of this study indicated that the biological SLUDGE generated from the three treatment plants in the winter after drying off naturally were located in class B of the EPA standards.Thus, based on recommendations of the organization, such SLUDGE can be used with regards to standard restrictions for agricultural purposes. However, the microbiological quality of the SLUDGE in summer was lower than the U.S. EPA standards for Class B SLUDGE, and thus is not applicable in agricultural use.

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.

This research aims at study of the effect of sulfide on operation of one of the aerobic biological treatment PROCESSes, ACTIVATED SLUDGE. For this purpose, two pilot plant units were designed and constructed. One of these units was run for wastewater sulfide contaminant (sample), and the other one was run for wastewater without sulfide contaminant (Reference). First of all, in a quantities study, sample system was run with different influent sulfide concentrations, and compared with reference system. Then, concentration of influent sulfide was increased gradually until the inhibitory effect of sulfide on treatment PROCESS appeared. Finally, the concentration at which sulfide was inhibitory and resulted in PROCESS malfunction was determined. Also, the reference system was run with different influent COD and detention times. At the end, the behavior of pilot plants of the reference system and the sample system, were simulated with Contois model, and the microbial growth kinetic coefficient, and inhibiting coefficient of sulfide were defined.

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.

The biodegradation of Cypermethrin (20 to 125 mg/L) in effluent using batch ACTIVATED SLUDGE was studied. Degradation was found to occur to a great extent only in the presence of Pseudomonas (IES-Ps-1) culture. Under aerobic conditions using mechanical aerators, Cypermethrin (20 mg/L) was almost completely degraded in just over 48 h at ambient temperature. Further loading of organic compound in subsequent experiments demonstrated that IES-PS-1was capable to degrade 82 % Cypermethrin at 40 mg/L dose in approximately 48 h. When the concentration was increased to 80 mg/L, 50% degradation of this compound was observed. Over this time period the cells could utilize only 17 % of Cypermethrin when it was given 125 mg/L, respectively. These findings indicate that increased concentration of Cypermethrin has a marked effect on biodegradation performance of IES-Ps-1 with a modest increased in the duration of lag phase, but did not lead to complete inhibition or cell death. These results proved that IES-Ps-1 is responsible for Cypermethrin degradation. Such finding may be useful in designing a scale-up in situ or on-site hazardous waste bioremediation PROCESS for field application.