Biological Remuval of Nitrogen and Phosphorus using Activated Sludge Treatment in Meat Processing Wastewaters
Abstract
The main purpose of this study was to identify the best treatment techniques for wastewater discharged from meat processing. The organic matters in the meat industry wastewater are considerable and complex. To identify the organic component of wastewater we use the parameters to classify it. The most common parameters are the oxygen demand values. We have evaluated the two most common oxygen demand methods, the biochemical oxygen demand and the chemical oxygen demand. In this investigation thorough pretreatment studies were done using the activated sludge treatment.
This treatment was performed at optimal pH using different dosages of activated sludge.
Minimization of wastewaters discharges consist on keeping under continuous control: the quality of wastewaters; their treatment and disposal in an environmentally manner, optimization of processes, maintenance and respective design.
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Introduction
The processing of meat and meat by-products requires large quantities of potable water, and nearly all of this is discharged as high strength organic, nutrient (nitrogen and phosphorus), fat and microbial contaminated effluent. Many of the processing plants are rural based and therefore require on-site treatment with discharge limits that are becoming tighter as community expectations increase for better treated wastewater discharges, especially into surface water.
The meat industry has to deal with a number of environmental challenges. Thisincludes responsible wastewater treatment and disposal to prevent land and waterpollution. A well designed and managed wastewater treatment system is essential to achieve regulatory requirements and help protect and maintain a sustainableenvironment.
By focusing on reducing water usage, optimize wastewater treatment and improved waste management, both disposal and treatment costs can be reduced.
iological wastewater treatment is often associated with secondary wastewater treatment and intends to treat the dissolved and colloidal organics after primary treatment. The goal of all biological wastewater treatment systems is to coagulate and remove or reduce the nonsettling organic solids and the dissolved organic load from the effluents by using microbial communities to degrade the organic load. Biological wastewater treatment is generally a major part of secondary treatment design of wastewater and characterized by reduction of the oxygen demand of an influent wastewater to a given level of purification. The microorganisms responsible for reducing the organic matters and consequently the oxygen demand of incoming wastewater can be classified in aerobic and anaerobic.
Aerobic biological treatment dominates secondary wastewater treatment and is performed in the presence of oxygen by aerobic microorganisms. From a nutritional point of view, the majority of microorganisms in biological wastewater treatment systems use the organic matters in the wastewater as the energy source for growth and maintenance of microorganisms.
Anaerobic processes are also used in the secondary biological treatment of wastewater. Anaerobic processes, in addition to sludge digestion, are employed to treat high-strength wastewater, such as food-processing wastewater streams.
Conclusion
From the analysis of the physical-chemical indicators in the polluted waters discharged by the meat processing industry, all the parameters set were at a very high rate, in contradiction with the parameters set by the Albanian legislation on the Pollution Rate in the waters discharged by this industry. Treatment with the active sludge obtained from the secondary decanter resulted in a higher reduction of all the parameters.
The percentage reduction of the parameters from the treatment with AS from second settler are: TDS 64.66%; SS 60.84%; COD 76.37%; BOD5 92.64%; N-NO2 81.48%; N-NO3 99.14%, N-NH4 93.21%; P-PO4 90.21% and P-Tot 82.48%.
To prevent pollution, industries should stop immediately discharge wastewater in high values and to use methods or treatment that increase the efficiency of the removal of the organic matter in wastewater.
From this study we recommend that the meat industries should remove the solid mass (fat) to avoid the difficulty of the filtration process and treating wastewater with coagulant and active sludge to realize the reduction of parameters.
Design an anaerobic treatment process for wastewater treatment in slaughterhouses, as a high rate of COD reduction at a lower cost than aerobic systems is achieved and gas-generating methane-rich gas can be used as fuel.