DBO Bodies of water produce and consume oxygen. It gets its oxygen from the atmosphere and plants through photosynthesis. For flowing water, it would dissolve more oxygen due to the effect of its churning and continuous movement. Wastewater containing organic matter is broken down by microorganisms that use the oxygen contained in the flow. Biochemical oxygen demand (BOD) is the amount of oxygen consumed during this process. Other sources of oxygen-consuming waste include stormwater runoff from agricultural areas or septic tanks. In this aspect, oxygen is measured in its dissolved form (DO). If more oxygen is consumed than produced, it would affect the ecosystem supported by the waterway or transfer its oxygen-consuming inhabitants to less visible bodies of water. According to APHA, 1992 in their study “Standard Methods for the Examination of Water and Wastewater” DO levels fluctuate throughout the day and are influenced by temperature and altitude. The study also indicates that cold water has a higher oxygen holding capacity than warmer water. Water at 0°C had a DO level of 14.60 mg/L compared to water at a temperature of 36°C at a value of 6.82 mg/L. Similarly, in March 1997, the Department of Natural Resources at the University of Rhode Island pointed out that salinity, altitude, groundwater yield, and water temperature are some of the factors that influence the dissolved oxygen in a body of water. The higher the salinity of the water, the lower the amount of dissolved oxygen. Hot water normally contains less oxygen in solution than cold water. Thermal stratification (heating through different layers) causes DO depletion and eventually completely depletes the levels because there is no replenishment. According to an article by Simpson (1991), ...... middle of paper ...... dichromate, under acidic conditions. A known excess amount of this oxidant is added to the sample and once the process is complete, the COD concentration value is calculated by measuring the remaining amount of oxidant in the solution. This process is usually done by titration using an indicator solution. It is measured in milligrams per liter and indicates the mass of oxygen consumed per liter of solution. While the Biochemical Oxygen Demand (BOD) test requires 5 days, the COD test only takes about 2-3 hours to complete and analyze. As part of this test, it measures all organic contaminants present in the wastewater sample, including those that are not biodegradable. For the BOD test, toxic compounds such as heavy metals cannot be analyzed. The COD test can therefore be used to measure the resistance of waste that is too toxic for the BOD test...