Many reviews were published about SWM in developed and developing countries and about environmental contamination from waste. In particular, about char fuel production [20], management of waste electric and electronic equipment (WEEE) [21], food waste management [22] and treatment [23], recycling of used batteries [24], inclusion of the informal sector [25] and the risks that such activity pose for vulnerable informal workers [26], atmospheric pollution due to SWM [27], household hazardous waste management [28] and healthcare waste (HW) management [29], among others. The novelty of the narrative review presented in this article is its focus on the integrated assessment of these waste streams, analyzing the global issues affecting the environment and the public health, giving attention to the operational risk of the informal recycling sector. Concentration of contamination in water, air and soil are provided, as well as waste quantities and amounts dumped in developing cities or recycled by the informal sector. Results allow suggesting directions for future SWM improvements, considering its planning as an integrated system and providing examples of the consequences of its inadequate implementation.
Ls Land Issue 24 Future Schooll
In Cambodia, in the capital city Phnom Penh, where the MSW management (MSWM) system lacks regulation, households commonly burned, buried, or dumped about 361,000 tons of MSW in 2008, and 635,000 tons in 2015 [40]. In Thailand, more than 60% of the SW final disposal was carried out by open dumping. In 2004 there were 425 disposal sites, of which 330 open dumps, the majority of disposal sites received around 25 tons of waste per day, while only the landfills of Bangkok received about 4500 tons per day [41]. In the West Bank Palestinian territory, in 2005 was estimated that the MSW generated was about 2728 t per day, while in 2001 there were 133 MSW dumpsites, open burning activities at 116 sites and burial at 13 sites; 64.9% of the population was aware of the environmental issues and impacts associated with open dumpsites, and 41.6% thought that they were suffering from the final disposal sites [42]. In Abuja, the capital city of Nigeria, more than 250,000 tons of waste were generated per year in 2010. There were four major disposal sites under its management, closed in 2005 due to odors, air pollution and burning wastes at the site. Moreover, percolation of leachate from the buried waste flowed to the surface, especially during rainy seasons [43]. In Maputo, administrative center of Mozambique, with about 1,200,000 inhabitants and where about 0.5 kg of waste per inhabitants are generate daily, the MSW is transported to the official dumpsite of the city, in operation since more than 40 years. The area is of about 17 ha, with heights that achieved 15 m; open fires and auto ignition of the waste are common issues, exacerbated by the more than 500 waste pickers collecting recyclables waste at the dumpsite [44]. Therefore, SWM issues are common worldwide, with environmental burdens and hazard for the population.
Another environmental issue due to organic waste open dump is the GWP due to waste anaerobic degradation. Methane gas is a by-product of landfilling MSW; since MSW is mainly disposed of in open dump sites, the generated methane is released directly to the atmosphere. Experimental studies indicate that the anaerobic biodegradation of MSW organic waste generates about 200 Nm3 of methane per dry tons of biomass [58]. Methane is one of the most important gas that improve the GWP, 25 times higher than CO2 [59]. Therefore, open dumps and uncontrolled landfills are direct source of GHG.
The challenges facing the developing countries in WEEE and used batteries management include the absence of infrastructure for appropriate waste management, lack of legislation dealing specifically with these waste fractions, the absence of any framework for end-of-life product take-back or implementation of extended producer responsibility (EPR) [100]. Moreover, the growing rate of WEEE amount in developing countries is destined to increase in the next future [101]: A great amount (almost 50%) of current WEEE yearly generated by developed countries continues to be illegally transferred in developing countries, volumes that remains unknown; New electric and electronic products will substitute soon the current ones, influencing both collected volumes, type of recovered materials and recycling processes; Innovative materials composing WEEE, that are currently not correctly managed during their end-of-life (ending into landfills); some electronic parts in WEEE are not again correctly disassembled or recovered [101]. In summary, many challenging issues of WEEE and used batteries management can be detected in developing countries [102]:
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