Solid Waste Treatment

Introduction

The Environmental Protection Agency (EPA) defines municipal solid waste (MSW) as, “everyday items such as 

product packaging, yard trimmings, furniture, clothing, bottles, cans, food, newspapers, appliances, electronics, 

and batteries” that are discarded from residential, commercial, or institutional sources. However, the EPA’s MSW 

definition does not include industrial, hazardous, or construction and demolition (C&D) waste which is covered 

in a separate report card chapter on hazardous waste. 

Solid waste management includes infrastructure for landfills, converting waste to energy (WTE), and recycling or 

composting. MSW processing includes shredding, compaction, incineration, or biological degradation to reduce 

MSW volume. Thereafter, the garbage may be transported to landfills, discrete areas, or excavations designed to 

protect the environment from potential contaminants.

Another approach, the waste-to-energy (WTE) process, involves non-recyclables from the waste stream undergoing

 combustion, gasification, pyrolization, or anaerobic digestion to produce electricity and heat. Finally, recycling and 

composting efforts include collecting, sorting, processing, and remanufacturing materials and organics, respectively,

that are otherwise considered waste. 

Solid Waste Treatment

 The quality of life on the Earth is linked to the overall quality of the environment.

 Unfortunately, the progress in science, technology and industry a large amount ranging from

 raw sewage to nuclear waste is dumped into the ecosystem thereby posing a serious

 problem for survival of mankind itself on earth.

 Solid waste management (SWM) is one of the most challenging issues faced by developing

 countries that suffer from serious pollution problems caused by the generation of large

 waste quantities.

 The awareness that improper handling of SW leads to contamination of water, soil and

 atmosphere (causing global warming) and is a major impact on public health has caused

 developing nations to address this issue with increasing urgency: management of SW.

 In the world, several type of waste with billion tonnes of wastes per year are generated.

 Obviously, the biosphere system cannot absorb and recycle such a large amount of wastes.

 Most wastes were traditionally disposed by digging a hole and filling it with waste material

 (landfill sanitary) and burning the organic wastes in open land (Incineration).

 This mode of waste disposal: difficult to sustain owing to lack of new place every time to

 dump and create air pollution to the surrounding community as well as global warming.

 New technologies for waste disposal that use high-temperature incineration and chemical

 decomposition (e.g., base-catalyzed dechlorination, UV oxidation) have evolved.

 Although they are very effective at reducing wide a range of wastes/contaminants but have

 several drawbacks such as complex, uneconomical and lack public acceptance.

The associated deficiencies in these methods have focused efforts towards harnessing

 modern day bioremediation process as a suitable and sustainable alternative

Waste Characterization

 Solid waste characterization supplies useful data for choosing appropriate disposal

 methods and developing collection and separation systems.

 In characterization of municipal solid waste, amounts and types of the waste components

 varies with location, season, population density, economic conditions and others.

 Due to the heterogeneous nature of solid waste, common sense and random sampling

 techniques have evolved for determining composition.

Understanding the composition and nature of solid waste at the source of generation plays

 an important role in designing a method for an integrated waste management program.

 Landfill life can be predicted and modification can be made in present waste management by

 using characterization data. 

Possible to be sorted into populations by size, material type or suspected contamination.

 * Without a priori knowledge of the contents (percentages of type: paper, plastics, etc.) and the

 contaminants present (e.g., heavy metals, volatile organics, semivolatile organics, etc.) in a

 given collection site, it is difficult to selectively sort the material to obtain an estimate of the

 distribution of contaminants and decide methods of treatment. 

Basis of Biological Solid Waste Treatment

 Biological treatment processes use natural processes of ubiquitous living organisms.

 During biodegradation, microbial activity ‘recycles’ organic molecules, and such continuous

 process is fundamental to biological treatment.

 Biological treatment processes are well understood and widely used for organic wastes,

 mainly non-hazardous ones, but also used for some hazardous wastes such as heavy metals,

 xenobiotic compounds, etc.

 In solid waste, biological action takes place naturally within collection site, landfill sites and

 compost processes, and natural process is encouraged and optimised in biological treatment

 facilities by control of temperature, nutrient supply, pH, inoculums type and size, etc.

 Complicating biodegradation by "cometabolism" where minimum two substrates are needed

 i.e., one compound cannot fulfill all the bacterial needs and act as the sole carbon and energy

 source, whereas a second compound is needed as growth substrate.

 Different microbial actions take place in aerobic (or oxygen-rich), anoxic (low oxygen)

 and anaerobic (or absence of oxygen) conditions.

Aerobic degradation can take place over wider temperature and moisture ranges than anaerobic

 processes, because of the methane bacteria.

What is a Sanitary Landfill?

 The sanitary landfill is a technique for the final disposal of solid waste in the ground that

 causes no nuisance or danger to public health or safety; neither does it harm the

 environment during its operation or after its closure.

 Sanitary landfill can be also defined as a facility designed and operated as a basic

 sanitation project that has sufficiently safe elements of control, and the success of which lies

 in the selection of the suitable site, its design, and of course, its effective and efficient

 operation and control methods.

 This technique uses engineering principles to confine the waste to as small an area as possible,

 covering it daily with layers of earth and compacting it to reduce its volume.

 In addition, it anticipates the problems that could be caused by the liquids and gases

 produced during the decomposition of organic matter.

 Some materials such as paints, cleaners, chemicals, motor oil, batteries, and pesticides are

 some of the common items that are banned from MSW's disposal landfill.

The display of solid waste equipments :