The experience of operating surface runoff treatment facilities
and the guidelines for the improvement of sludge treatment technology

Swimmer

The data on the mechanical and physical properties of surface runoff sludge generated on the lands allotted for settlement and highways is presented. The observations of the processes of natural sludge drying on the sand sludge dewatering beds at the treatment facilities show that the sludge is characterized by low dewatering properties (more than 89–94%), and this fact stipulates the demand for the improvement of the sludge treatment technology. As a result of the chemical and analytical studies of the surface runoff sludge composition it was stated that the sludge from industrial sites located in the residential districts and industrial areas, from residential constructions on the lands allocated for settlement with parklands as well as from the recreation areas with nature-sanctuaries could be attributed to class IV of hazard (low-hazard). Sludge from the territory of the Moscow Ring Road, gasoline stations, and parking lots at the shopping malls could be attributed to class III of hazard (moderately hazardous). The results of the laboratory studies showed that the use of high molecular polyelectrolytes provided for sludge thickening and efficient dewatering by centrifuging to 74–82% moisture content. The design data on the sludge specific volume (98–99% moisture content) generated in storage tanks is presented as well as the data on the specific volume of dewatered sludge (89–94 % moisture content) generated annually on 1 ha catchment area for different types of catchment areas. It is recommended during the design process not to remove water charged sludge with a moisture content of 98–99% by trucks (sludge pumps) as an expensive and ineffective method, but to dewater sludge directly at the treatment facilities with the use of stationary or mobile mechanical equipment (vacuum-filters, filter-presses, centrifuges, geotubes).

Key words

treatment facilities , sludge , surface runoff , drainage area , the dewatering apparatus