Treatment/Disposal of Rejects/Effluents
The method of treatment and disposal of the final rejects/ effluents should be considered in advance. The utility of the same should also be considered as in case of anaerobic digestion, where about 70% of the input is discharged as sediment (digested sludge), but the same after being stabilized through aerobic treatment, can be used as a good fertilizer.
It should be borne in mind while adoption of any particular technology that MSW, though not classified as Hazardous or Toxic, may also contain some such waste component (solvents, paints, pesticides, sewage sludge, pathological wastes from hospitals, etc.). Proper Waste management requires that such waste materials are stored, collected, transported and disposed off separately, preferably after suitable treatment to render them innocuous and not mixed with the Urban Waste stream. The possibility, however, of Toxic & Hazardous wastes being present in the MSW, should be carefully examined and duly taken into consideration during their treatment/ processing and in the design of the WTE plants.
Plastic wastes may account for 1-10% of the total Municipal Solid Wastes.
They are highly resistant to bio-degradation, which makes them objectionable for release to the environment and of special concern in waste management. Plastics have a high heating value making them very suitable for incineration. However, PVC when burnt, may, under certain conditions, produce dioxin and acid gas, which calls for adequate safety measures as already discussed in previous sections.
