Industrial and livestock wastewater treatment
Wastewater treatment of livestock and agricultural industries with modern techniques in order to increase the efficiency of removing pollutants and reuse of treated wastewater in accordance with environmental standards.
The effluent from slaughtering animals and washing the carcasses of sheep, cattle and chickens contains fats, blood, fluids and solids in the animal's body, which in general has a relatively high pollution load.
Slaughterhouse sewage is very similar to domestic sewage but has a higher concentration. This type of wastewater is generally composed of organic matter and contains a lot of suspended solids and also has a high BOD5.
Pre-treatment of wastewater in livestock and agricultural industries includes the removal of all materials that can be easily collected from wastewater to prevent possible damage to mechanical equipment such as pumps and.. These materials include livestock and poultry waste such as feathers, skin, bones and.. The mentioned wastes are removed by passing the incoming sewage. The meshing of mechanical and manual contaminants is different in order to optimize the removal of solid particles.
Due to the fact that the amount of fat and oil in the sewage of slaughterhouses is high, the degreasing pool is necessary and inevitable in the treatment of wastewater in livestock and agricultural industries. In this unit, fat and oil are collected by skimmers installed on degreasing tanks. If the amount of fat and oil in the wastewater is high, aeration blowers are used to increase the removal efficiency. However, most refineries use mechanical skimmers to collect grease and oil. Degreasing methods that depend on the type of wastewater are: DAF degreasing, API degreasing, CPI degreasing
One of the problems that always plagues aerobic treatment methods of industrial wastewater is the lack of oxygen transfer to the aeration reactor. In this wastewater treatment of livestock and agricultural industries, which has a very high level of pollution (organic load), a lot of oxygen is required, which brings a high cost to microorganisms for aerobic digestion. Anaerobic treatment of such wastewater can be an effective option in reducing the organic load of wastewater and possibly increasing the efficiency of subsequent aerobic units. The main anaerobic processes widely used in industrial wastewater treatment are UABR, UASB, ABR.
The effluent from the anaerobic reactor enters the aerobic reactor to complete the treatment process and meet environmental standards. At this stage, with the aeration of wastewater, the decomposition of the remaining organic matter is done by aerobic microorganisms. Aerobic biological systems are classified into two categories: mobile bed growth (MBBR), adhesive growth activated sludge (IFAS) and floating biological growth (EAAS). In MBBR the media is floating but in IFAS the media is fixed.
Disinfectants are used to remove microorganisms so that when using treated wastewater in irrigation and green space and… environmental problems do not occur. Effective disinfection depends on the quality of the treated effluent, the concentration of the disinfectant, the residence time, the type of disinfectant, and so on. Chlorine, UV lamps and ozone are three common methods of disinfection. Today, UV lamps have received more attention due to their high efficiency in removing microorganisms, non-use of chemicals and easy operation.