Monitoring Water Quality through Chemical Oxygen Demand: A comparison of Natural and Domestic Water Sources

Monitoring Water Quality Through Chemical Oxygen Demand: A Comparison of Natural and Domestic Water Sources Chemical Oxygen Demand (COD) is an important measurement used in environmental science to check water quality and pollution levels. It measures how much oxygen is needed to chemically break down materials in a water sample. High COD values mean there are many pollutants, which can quickly use up the dissolved oxygen in aquatic environments. This lack of oxygen harms marine life, upsets ecosystems, and ruins water quality.The goal of this study was to measure and compare the pollution levels of local natural waters against household wastewater. We hypothesized that household waste would have much higher COD levels than natural surface water due to concentrated organic materials.To test this, water samples were collected from different sources, including natural environments like lakes and household environments like tap water, wastewater, and urine. The testing followed the standard USEPA Method 410.3. Each sample was boiled for two hours with a potassium dichromate solution, concentrated sulfuric acid, and a silver sulfate catalyst. After boiling, the remaining chemical was titrated against a standard ferrous ammonium sulfate solution to calculate the fi nal COD values in milligrams per liter (mg/L).The results showed clear differences in pollution levels between the natural and household samples. Natural waters and tap water showed excellent quality, with very low COD levels between 1.0 mg/L and 3.0 mg/L. In contrast, household waste showed severe pollution. Kitchen wastewater had a high COD value of about 2,000 mg/L. Human urine had the highest pollution level, reaching over 11,000 mg/L.These fi ndings show the heavy impact of household waste on water systems and prove that EPA titration is effective for tracking local ecosystems. The huge difference between clean natural water and household waste highlights the need for good wastewater treatment. Treating household waste before it enters the environment is necessary to prevent harming ecosystems and to protect public health.