INTRODUCTION
Loosely described as discarded and used products, wastes have been one of the realities of modern day living. The urban solid waste varies in composition from country to country. The nature and composition is more organic in developing and under developed country, than the developed nations. In India, the State Pollutions Control Boards working in conjunction with the Central Pollution Control Boards, have defined solid waste as, those undesirable useless and unwanted materials and substances that arise from animal and human activities (MPCB, 2016). Generically solid waste can be categorised into, depending on their source, into, Household waste (also called municipal waste), Industrial waste as hazardous waste, Biomedical waste or hospital waste as infectious waste, Hazardous Waste and electronic waste. Historically wastes has been generated in all countries and have been despised within and in the outskirts of the cities, towns or urban agglomerations. Over time with the rise in population and the compounding increase per capita of the waste generation, the waste volumes have also headed northwards. Dumpsites and open dumping have been the most preferred way to dispose the wastes effectively and economically. With the increasing pressure on land and their occupation for urban infrastructures, in many cities the dumping yards have been located on or next to inland rivers, creeks, nalas (a local name for storm water channel) or estuarine regions. India has several cities which have such dumpsites, by the inland water bodies, namely, the Dhapa Dumpyard (East Kolkata Wetlands), Gorai, Mahim, Creek and Thane Creek (Manori Creek, Mumbai), Mavallipura (Bangalore), Astamudi Lake (Kerala) Adyar River (Chennai), Sheeshambada (Dehradun), Yamuna and Gazipur (Delhi), to mention a few. In Africa, Agbogbloshie (Odaw River, Ghanna), Shey Wenz River, Ethiopia are some examples.
Globally the amount of waste produced is a whopping 11.2 billion, out of which solid waste is 2.01 billion (World Bank1 2016), which is expected to rise to 3.04 billion in 2050(World Bank, 2016). Different countries produce unequal amounts of Municipal Solid Waste depending on the level of development of the country, i.e. developed nations have more inorganic and recyclable wastes in their municipal solid waste while developing and under developed nations have more organic waste than the inorganic waste in their municipal solid waste bins and yards. United States, is the leading producer of municipal solid waste, at, 258 million metric tonnes, followed by China(220.4 million metric tonnes) and India(168.4 million metric tonnes) (Tiseo, 2020).Other countries in Africa, Nigeria(27.61 million metric tonnes) South Africa (18.46 million metric tonnes) while EU as per Eurostat has reduced its waste generation to 53 million tonnes in 2019 (Eurostat, 2021),from 121 million tonnes in 1995, owing to waste management, recycling, bioremediation, incineration among others. Waste disposal, be it MSW, Hazardous waste or even Plastic Waste has been creating waste gluts in the world. Countries with high volumes of waste have been dumping them into nations thereby creating waste flows. The waste flows generally have been dumped in East Asian nations and post 2016, the trends have been to dump the waste in the Latin American countries.
Waste once generated needs to be managed through various methods. One of the oldest has been dumping them on the outskirts of the city. Ancient Indian cities as with many older European cities ensured that carts travelling to the city were loaded with the refuse of the city to be disposed in the outskirts. These have evolved into landfills. India for example the Dhapa Dumping Yard, the Gazipur Dumping Ground or the Deonar Dumping Ground has been the same. Waste management can also be undertaken by segregating the waste into the dry and wet waste. The Dry waste is recycled to recover the resources while the wet waste is reduced through composting and bio remediation. The hazardous waste of the Municipal Solid Waste and also the biomedical waste is incinerated under controlled conditions. The other ways to manage the waste is to generate energy through the Waste to Energy generation units set up in the facilities of waste collection. These help harness the landfill gases. Finally some of the recyclables have been brought to alternative uses such as bricks, stationary, reuse of plastic, paper etc.