Environmental Engineering Reference
In-Depth Information
37.1 Introduction
37.1.1 Municipal Solid Waste Dumping
Municipal solid waste (MSW) management is a major environmental problem in many coun-
tries worldwide [1]. Globally, hundreds of megatons of waste is generated each year (i.e., MT/
ye a r >10
8
) and MSW is a dominant stream that contributes a signiicant fraction to the total
content of waste [2]. Most countries worldwide practice different waste management methods;
several are with successful stories, and some are poorly designed or poorly managed with
demerits [3]. Developed countries use advanced MSW management methods such as waste
incineration and bioelectricity for generation of electricity instead of conventional waste man-
agement methods [4,5]. The management of waste has become a critical concern for most of
the developing countries because of the absence of appropriate waste management methods
[6]. However, only a few local bodies and some institutes in developing countries are practic-
ing composting, anaerobic digestion, and valuable materials recovery using MSW as solutions
instead of open dumping and burning of waste [7,8]. On the other hand, population incre-
ments with rapid urbanization, industrialization, and modernization as way of life are gener-
ating more waste content that is complex in nature. Mainly, MSW is the major fraction for the
total waste content that comprises biodegradable material, plastics, metals, construction and
demolition waste, electronic and hazardous waste, etc. However, it is dificult to categorize
the different types of waste because of their complex characteristics and disposal procedures.
Most of the Asian countries practice open dumping and nonengineered disposal of
waste since it is easy and cheap [1]. Sri Lanka's commercial city, Colombo, in the western
province itself has about 60 locations as open dumps that are currently being maintained
by the local authorities, well an example of this situation [9]. Furthermore, recent studies
have revealed that MSW of about 3700 tons is being generated each day in Sri Lanka [10].
One of the most critical aspects associated with open dump sites is the formation of
leachate, which is well understood as a typical contaminant containing a large amount
of pollutants [11]. The higher biodegradable fraction or organic content that is typically dis-
posed in large content in Sri Lankan dump sites may raise many issues due to the forma-
tion and direct discharge of highly polluted leachate into the environment [12]. Frequently,
this complex leachate is released to the nearest water body without any treatment mech-
anisms. This can lead to much adverse impact on the local soil and water sources [13].
Unfortunately, most of the open dump sites are located close to the water bodies, which
even magnify the adverse impacts with an accelerated rate. In addition, the landill leach-
ate is shown to be highly toxic to higher plants, algae, invertebrates, and ish [14]. Therefore,
economically viable, environmentally friendly, and socially acceptable solutions are
needed and commissioned for the responsible authorities immediately to overcome land-
ill leachate-related issues to ensure environmental sustainability.
37.1.2 Characteristics of Landfill Leachate
Many countries have identiied landill leachate as a typical contaminant for surface water,
groundwater, and soil fertility due to its toxicity [15]. High concentrations of Cd(II), Hg(II),
Ni(II), Mn(II), Cu(II), Zn(II), and Pb(II) have been reported associated with leachate, and
these metals have been identiied as enhancing their transportation with dissolved organic
carbon derivatives by anaerobic degradation of organic compounds present in the leachate
such as humic, fulvic, and hydrophilic compounds [11,16,17]. Furthermore, inorganic ions
