Waste Management & Waste-to-Energy

Part 2 · The possible approaches for management of wastes

From Open Dumps to Composting

The common ways of disposing of waste, how each works and what goes wrong, followed by the biological methods and the four R's.

Open dumps refer to uncovered areas that are used to dump solid waste of all kinds. The waste is untreated, uncovered, and not segregated.
It is the breeding ground for flies, rats, and other insects that spread disease. The rainwater run-off from these dumps contaminates nearby land and water thereby spreading disease.
Treatment by open dumps is to be phased out.

Biological methods and the four R's

Composting

Composting is a biological process in which micro-organisms, mainly fungi and bacteria, decompose degradable organic waste into humus-like substance (an excellent medium for growing plants) in the presence of oxygen.
Apart from being clean, cheap and safe, composting can significantly reduce the amount of disposable garbage.

Vermiculture

It is also known as earthworm farming. In this method, earthworms are added to the compost. These worms break the waste and the added excreta of the worms makes the compost very rich in nutrients.

Four R's

Refuse, reduce, reuse and recycle.

Part 3 · How science and technology can eradicate the problem

Science and Technology for Waste

Heat without oxygen, plasma, microbes and nanomaterials can turn waste into fuel or harmless products; reuse turns it into wealth.

Pyrolysis

It is a process of combustion in absence of oxygen or the material burnt under controlled atmosphere of oxygen. It is an alternative to incineration. The gas and liquid thus obtained can be used as fuels.
Pyrolysis of carbonaceous wastes like firewood, coconut, palm waste, corn cobs, cashew shell, rice husk, paddy straw and saw dust, yields charcoal along with products like tar, methyl alcohol, acetic acid, acetone and a fuel gas.

Plasma gasification

This process of waste management utilises highly ionised or electrically charged gases called plasma within a vessel to convert carbon-based materials into fuel.
It is an emerging technology that treats hazardous waste by converting incinerator ash or chemicals into non-hazardous slag. The high temperature and lack of oxygen prevent the formation of toxic compounds like dioxins, NOx, furans or sulphur dioxide.
The whole processing of waste is ecologically clean, converting solid or liquid wastes into a syngas.

Using biotechnology

Biotechnology finds application fields in the treatment of wastewaters by biological methods and disposal of solid wastes by composting technique in waste management. Biological methods are also applied to treatment of air emissions.
The methods based on biotechnology in wastewater treatment are activated sludge, trickling filters, oxidation ponds, biofilters and anaerobic treatment. Furthermore, solid waste composting techniques, biotrickling filters and biosorption are the examples of biotechnology applications in waste management.
Biotechnology for Waste Management using Microbial Fuel Cell. It not only helps in waste water management but also produces energy simultaneously.

Bioremediation

In this process, the micro-organisms (bacteria and fungi) are used to degrade the Hazardous wastes into less toxic forms.
In-situ bio-remediation techniques are Bio-venting, Bio-sparging and Bio-augmentation.
Ex-situ bio-remediation techniques are Landfarming, Bio-piles, Bio-reactors and composting.
Hazardous wastes can be converted to non-toxic products using this natural degradation process. The limitations are that it takes a long time, and controlling the natural process of degradation can be hard.

Example: In-situ means treating the contamination where it lies, for example pumping air into polluted soil so that its own microbes break down oil (bio-venting). Ex-situ means digging the soil up and treating it elsewhere, for example spreading it on land and tilling it (landfarming).

Nanotechnology

Nanotechnology can be employed either for in-situ or ex-situ waste management technologies.

Nanomaterials such as nZVI, can be used.
Nanomaterials can be also used in ex-situ waste management technologies. These technologies are commonly based on processes such as adsorption, membrane filtration and separation and photocatalysis. Owing to their size, nanoparticles exhibit high surface area, thus enhancing the adsorption of pollutants on their surface.

Waste to Energy (WtE)

An efficient disposal system is essential to save ourselves and the environment from non-recyclable items. The disposal technique generates heat or electricity from waste materials.
Reducing the need for fossil fuel can help decrease carbon emission.

Waste to wealth techniques

Use of plastic waste in road construction.
Toys from Trash: e.g. Padma Shri recipient, Arvind Gupta speaks about creating toys from recycled products to help create an equal and sustainable education system.

Part 4 · The potential to generate energy through waste in India

How Much Energy India's Waste Can Give

Estimates of power from city and industrial waste, the plants built so far, and the four techniques that turn waste into energy.

According to Ministry of New and Renewable Energy estimates

The solid waste generated from cities/towns in India has a potential to generate power of approximately 500 MW, which can be enhanced to 1,075 MW by 2031 and further to 2,780 MW by 2050.
The total estimated energy generation potential from urban and Industrial organic waste in India is approximately 5,690 Megawatt. (Minister of MNRE in a written reply in Parliament)
India has so far installed 96 waste-to-energy projects for generation of power based on urban, industrial, agricultural and municipal solid waste.
Current Capacity: There are five municipal Waste to Energy plants operational in India, with a total capacity to produce 66.4 MW electricity per day, of which 52 MW per day is generated in Delhi.

Power potential of city solid waste (MW)

By 20502,780 MW
By 20311,075 MW
Now500 MW

MNRE estimate; the current figure is approximate.

It uses MSW as a fuel, burning it with high volumes of air to form carbon dioxide and heat. In a waste-to-energy plant that uses incineration, these hot gases are used to make steam, which is then used to generate electricity.

Part 5 · Need of waste-to-energy plants and the challenges

Why India Needs Waste-to-Energy, and What Holds It Back

WtE cuts landfill, methane and transport while giving round-the-clock power, but India's wet, mixed waste, toxic ash, costly power and local protests stand in the way.

Need of waste to energy plants

Problems of unscientific Municipal Solid Waste (MSW) disposal: Only about 75-80% of the municipal waste gets collected and out of this only 22-28% is processed and treated and remaining is disposed of indiscriminately at dump yards. It is projected that by the year 2031 the MSW generation shall increase to 165 million tonnes and to 436 million tons by 2050.
Harmful emission from Landfills: Organic decomposition of food waste mixed with municipal solid waste at landfill sites leads to high amounts of emissions which is also a public health issue.
Net Greenhouse Gas Reducer: Methane is a greenhouse gas which is mostly emitted from decomposing waste in landfills. WtE facilities avoid the production of methane while producing almost ten times more electricity from each ton of waste compared to landfills.
Resource savings and recovery greatly expanded: Metals left in the municipal solid waste stream can be extracted from the ash resulting from incineration and the metals can be recycled.
24*7 Electricity: WTE facilities, unlike wind and solar, are capable of providing 24*7 renewable electrical power.
Landfill usage and expansion greatly reduced: Waste to energy facilities typically reduce waste volumes by 90%. Fewer and smaller landfills are needed to process.
Transportation of waste long distances can be greatly reduced with a waste to energy facility in a community, resulting in less air pollution.

Challenges

Low Calorific Waste: Municipal waste in India is often not segregated properly. It has a very high biodegradable (wet) waste content ranging anywhere between 60 and 70 per cent of the total, compared with 30 per cent in the West. This gives our waste a high moisture content and low calorific value. In Delhi, for example, only 12 per cent of the waste can be thermally treated through incineration technologies.
Example: Wet kitchen waste is mostly water. Burning it is like trying to light a fire with damp leaves: much of the heat goes into boiling off the water, so little is left to raise steam for electricity.
High Toxic Waste: Incinerators develop toxic ash or slag, containing heavy metals and gas pollutants which are toxic (corrosive impact) and pollute underground water.
Expensive power: Compared to Rs 3-4 per kWh from coal and solar plants, WTE plants sell electricity at about Rs 7/kWh.
Lack of indigenous technology, and high capital and operation and maintenance costs of waste-to-energy systems.
Lack of Finance for Urban Local Bodies (ULBs) affects institutional capacity necessary for integrated management of municipal solid waste, which requires investments for WtE projects.
Other Challenges include irregular and inadequate quantity of supply; non-payment of agreed fee and non-marketability of waste processed projects, including power.
Protests by locals against setting up such plants:
- Recently, residents of Okhla and surrounding areas in Delhi have been protesting against WtE plant in their vicinity.

Part 6 · Government initiatives

Government Initiatives for Waste-to-Energy

NITI Aayog's push for incineration, central financial assistance for energy from waste, Swachh Bharat targets and segregation rules.

Government initiatives

NITI Aayog in its Three-Year Action Agenda 2017-18 to 2019-20 has suggested that municipal solid waste be burnt to produce energy. Some proposals are:
- Composting and biogas are not sustainable since they generate by-products or residues in large quantities. Only incineration, thermal pyrolysis and plasma gasification technologies offer sustainable disposal solutions.
- Incineration is preferable to pyrolysis (which is unsuited for our municipal solid waste) and plasma technology (which is too costly).
- Setting up Waste to Energy Corporation of India, under the Ministry of Urban Development, to speed up the process of cleaning municipal solid waste.
Program on Energy from Urban, Industrial and Agricultural Waste/Residue for creating conducive conditions and environment with fiscal and financial regime to develop, demonstrate, and disseminate utilization of wastes and residues for recovery of energy.
- Central financial assistance (CFA) in the form of capital subsidy and grants-in-aid will be provided for biogas production from industrial waste, sewage treatment plants, etc.
Swachh Bharat Mission (SBM): 100% scientific processing and disposal of municipal solid waste is envisaged by 2019. WTE plants are key to Mission since they lead to the most scientific disposal of waste.
- Niti Aayog has, under the Swachh Bharat Mission, set a target of constructing 800 megawatt (MW) of WTE plants by 2018–19, which is ten times the capacity of all the existing WTE plants put together.
India's Solid Waste Management policy requires that wet and dry wastes should not be mixed so that only non-compostable and non-recyclable wastes with at least 1500 Kcal/kg should reach WtE plants.

Waste as wealth

Yes, India needs to spend a lot of money to create an effective waste management infrastructure but a clean India will be able to earn more by attracting more tourists. Moreover, new jobs will be created and people will start looking at waste as an opportunity to create wealth.

As India continues to rebuild, its citizens should ensure that they avoid reaching the dangerous levels of the average westerner in plastic consumption and waste production because waste reduction is better than any kind of waste management. And India's traditional wisdom of “Aparigraha” (the virtue of non-possessiveness, non-grasping or non-greediness) which is very relevant even today can play a key role in achieving that.

Exam preparation

BPSC Mains Previous Year Questions

Every question this page prepares you for, with the parts that answer it.

Q164th BPSC · 2018

Manifold increase of population and non-planning has led to disproportionate garbage generation. Discuss the different types of wastes. How can the country eradicate this problem with the help of science and technology? Describe in detail.

Study:The Waste Problem Dumps to Compost S&T Solutions

Q248–52nd BPSC · 2009

Write an account on the possible approaches for management of wastes and their potential to generate energy in India.

Study:The Waste Problem Dumps to Compost S&T Solutions Energy Potential Need & Challenges Government Initiatives

Quick revisionDumps, landfills and incineration Quick revisionFour waste-to-energy techniques Quick revisionAparigraha: reduce first

Waste Management & Waste-to-EnergyFrom Garbage Mountains to Power

India's Waste Problem and the Types of Waste

The wastes are of various types