In this article we will discuss about the sources and disposal of solid wastes.
Sources of Solid Wastes:
Solid waste is commonly known as everything that goes out in trash.
The various sources are:
(i) Municipal solid wastes contain wastes from the homes, offices, schools, hospitals, etc., that are collected and disposed by the municipality. It generally consists of paper, leather, textile, rubber, glass, waste food materials, etc.
(ii) Industrial wastes contain wastes like scraps, fly ash, etc., generated by industries.
(iii) Hospital wastes contain disinfectants and other harmful chemicals generated the hospitals.
(iv) Fly ash from thermal power plants is mainly composed of oxides of iron, silica and aluminium and a low concentration of toxic heavy metals.
(v) Electronic wastes (E-wastes) are the damaged electronic goods and irreparable computers.
(a) E-wastes are buried in landfills or incinerated.
(b) About half of the e-wastes generated in the developed world are exported to developing countries, mainly to China, India and Pakistan, where metals like copper, iron, silicon, nickel and gold are recovered during recycling process.
(c) Recycling of e-waste in developing countries often involves manual participation, thus exposing workers to toxic substances present in e-wastes.
(d) Developed countries have specifically built facilities for the recycling of e-wastes.
Methods of Solid Waste Disposal:
There are various following methods of solid waste disposal:
(i) Open burning involves burning of municipal waste in open dumps to reduce volume but the un-burnt piled waste serves as breeding ground for rats and flies.
(ii) Sanitary landfills are areas, where wastes are dumped in a depression or trench after compaction and covered with dirt. These have been adopted as an alternative to open burning dumps. Seepage of chemicals from these landfills can pollute underground water resources.
(iii) Rag-pickers and kabadiwallas collect and separate out wastes into reusable or recyclable categories.
(iv) Natural breakdown involves dumping biodegradable materials into deep pits for natural degradation.
(v) Recycling of e-wastes can be done in specifically built facilities or can be done manually to recover important metals. Recycling is the only way for managing e-waste, if it is done in an eco-friendly way.
(v) Incineration is a method of e-wastes disposal. Mostly developed countries export their e-wastes to developing countries for incineration.