This paper presents removal efficiency of dry diffuse pollutant through street sweeping and rainfall in Western Australia. Sweeping and rainfall removal of the dust and dirt (DD) and associated pollutants on single land-use impervious areas (parking and roads) were observed. Dust and dirt sampling was done before and after cleaning and rainfall on roads and parking areas in the Curtin University Bentley campus. The collected samples were analyzed for organic matters, phosphorus and heavy metals.
Removal efficiencies were estimated by the difference of DD and associated constituents before and after cleaning and rainfall.
Average total solid DD removal was between 20 and 66% in the study areas. Average removal efficiency increases as particle sizes increases and is 20-40% for particles less than 75 µm, 30-50% for less 75-150 µm and 70-98% for particles sizes above 1180µm. Sweeping removal efficiency of the constituents associated with DD were in the range of 35–60% for phosphorus, 48-62% for zinc, 50-65% for lead and 56-71% for copper.
Total solid DD removal in observed rainfall events were 20–50% in parking areas, 18-40% on smooth roads and 33-45% on rough roads. Average DD removal efficiency decreased as particle sizes increased in the study area and was about 60-80% for particles less than 75 µm, 40-55% for particle sizes between 75-150 µm and 0-25% for particle sizes above 1180 µm. averge removal efficiency of the constituents associated with dust and dirt was in the range of 15–30% for TP, 17-32% for Zn, 12-33% for Pb and 15-33% for Cu.