ln this, solid wastes are dumped into low lying areas. The refuge is dumped in layers of about 1.5 metre and each layer is covered by soil of about 20 cm thickness. Such landfills can be used for developing parks .0r 0ther recreational sites. So dumping is simple and economical method to manage the urban solid wastes reclaim the low-lying areas for better use.
In this organic matter of solid wastes is digested anaerobically or aerobically by microbial action and converted into humus and stable mineral compounds. Although aerobic composting is more attractive, it has a drawback that most of the composting plants have unacceptable odour. However. it is of great use, if its products are used as manure in soil. The crop yield is improved and there is less need of tertilizers and pesticides. Anaerobic composting is, more advantageous due to:
- No need of aeration.
- Produces biogas (50-70% methane and 30-40% CO2) which can be used for heating or generation of electric power.
- It involves the aerobic burning of the combustible constituents of solid wastes like garbage, rubbish and dead animals in the properly-constructed hearth of furnaces at high temperature (> 670oC). It can also be used to generate steam power (when burnt at about 1000oC temperature). This is also the idea method for medical waste management as, it eliminates the infectious organisms.