The study compared the water quality of cleaning wastewater and stormwater runoff from highways. Cleaning wastewater had much higher levels of pollutants like CODcr and heavy metals (Cu, Fe, Zn) compared to stormwater runoff. However, the total amount of pollutants discharged was low in cleaning wastewater. This suggests that managing stormwater runoff carefully can help reduce overall pollutant loadings, while cleaning wastewater should be handled cautiously due to its high pollutant concentrations.