Pre-treatment: By mechanical, chemical and physico-chemical methods to remove solid waste, suspended solids (SS) ... from the water source. In addition, there is a function to stabilize the quality of wastewater such as adjusting the pH, flow and loading of pollutants in the waste source.
Biological treatment stage: Mainly use the methods of treatment such as: anaerobic, aerobic, airless to remove the organic compounds soluble in water to reduce the BOD, COD, TN, YP ... in the water. This process works well when the substrates (compounds containing carbon), nutrients (nitrogen and phosphorus compounds), oxygen levels in water, etc. are properly added. .
Finishing stage: In order to stabilize the water quality, disinfect the water before discharging into the environment. This stage usually uses chemical methods to process. At the end of the treatment process, the output water ensures the quality of waste discharge without affecting the environment.
Sludge treatment stage: Use mechanical and physicochemical methods to reduce sludge volume or transfer solid-state to solid state for other purposes such as discharging or composting. microbiology
WHAT IS COD, BOD?
- DO is the amount of dissolved oxygen in the water required for the respiration of aquatic organisms (fish, amphibians, aquatic animals, insects, etc.) that are usually produced by atmospheric dissolution or photosynthesis. algae DO concentrations in the water range from 8 to 10 ppm, and fluctuations are strongly dependent on temperature, chemical degradation, photosynthesis and etc. When the DO concentration is low, water species decline. active or dead. As a consequence, DO is an important indicator for assessing water pollution in water bodies.
- BOD (Biochemical oxygen Demand): the amount of oxygen needed to microorganism oxidize organic matter by reaction:
Bacteria: Organic matter + O2 = CO2 + H2O + new cell + intermediate product
In a water environment, when biological oxygenation occurs, microorganisms use dissolved oxygen, so determining the total dissolved oxygen required for biodegradation is an important measure of evaluation. The effect of a waste stream on water sources. BOD signifies the amount of organic waste in water that can be decomposed by microorganisms.
- Chemical Oxygen Demand (COD) is the amount of oxygen needed to oxidize chemical compounds in water, including inorganic and organic. So COD is the amount of oxygen needed to oxidize all the chemicals in water, while BOD is the amount of oxygen needed to oxidize part of organic compounds that are easily decomposed by microorganisms.
The total amount of oxygen used for these reactions is taken from dissolved oxygen (DO). Hence, the need for high chemical oxygen and oxygen levels will reduce the DO concentration of water, which is harmful to aquatic organisms and water ecosystems in general. Organic wastewater, household wastewater and chemical effluent are the agents that produce high BOD and COD values of the water environment.
