Solid waste includes solids or semisolids, non-soluble materials (including gases and liquids in containers) such as agricultural refuse, demolition waste, industrial waste, mining residues, municipal garbage, and sewage sludge.
The most common types of solid waste are:
- Municipal Solid Waste
- Industrial Waste
- Agricultural Waste
- Hazardous Waste
The solid waste composition varies from region to region and time to time. There are following different types of solid waste.
- Biodegradable waste i.e. could be decomposed naturally such as food and kitchen waste, green waste, paper, etc.
- Recyclable material i.e. could be recycled again and again; such as paper, glass, bottles, cans, metals, certain plastics, fabrics, clothes, batteries etc.
- Inert waste i.e. not liable to decompose; such as construction and demolition waste, dirt, rocks, debris, etc.
- Electrical and electronic equipment waste (WEEE); such as electrical appliances, TVs, computers, screens, etc.
- Composite wastes; such as waste clothing, tetra packs, waste plastic, etc.
- Domestic hazardous waste and toxic waste medication; such as paints, chemicals, light bulbs, fluorescent tubes, spray cans, fertilizer and pesticide containers, shoe polish, etc.
Solid waste generation in Pakistan ranges between 0.283 to 0.612 kg/capita/day and the waste generation growth rate is 2.4% per year. Solid domestic waste is typically dumped on low-lying land. This land could be used for more productive purposes and potentially valuable recyclable materials are lost.
Main problems regarding solid waste management in Pakistan are:
- There is no proper waste collection system
- Waste is dumped on the streets
- Different types of waste are not collected separately
- There are no controlled sanitary landfill sites
- Citizens are not aware of the relationship between ways of disposing of wastes and the resulting environmental and public health problems
The unavailability of proper disposal methods and resources for solid waste management results in various environmental and human health hazard effects. Such problems or effects can spread over a wide area.
Some common health hazards caused by solid waste are mentioned in the following:
- Skin and eye infections are common
- Dust in the air at dumpsites can cause breathing problems in children and adults
- Flies breed on uncovered piles of rotting garbage and spread diseases like diarrhoea, dysentery, typhoid, hepatitis, and cholera
- Mosquitoes transmit many types of diseases like malaria and yellow fever
- Dogs, cats and rats living around refuse carry a variety of diseases including plague and flea born fever
- Intestinal, parasitic and skin diseases are found in workers engaged in collecting refuse
The most serious problem is groundwater contamination. As water filters through any material, chemicals in the material may dissolve in the water, a process called leaching. The resulting mixture is called leachate. As water percolates through Municipal Solid Waste, it makes a leachate that consists of decomposing organic matter combined with iron, mercury, lead, zinc, and other metals from rusting cans, discarded batteries and appliances. It may also contain paints, pesticides, cleaning fluids, newspaper inks, and other chemicals. Contaminated water can have a serious impact on all living creatures including humans in an ecosystem.
When waste is burnt heavy metals like lead, toxic gases, and smoke spread over residential areas. The wind also carries waste, dust and gases caused by decomposition. Putrefaction of waste in sunlight during daytime results in bad smells and reduced visibility.
Solution - Solid Waste Management
There is an urgent need to manage Municipal Solid Waste (MSW) from the time it is created to its safe disposal. The public and local municipal authorities need to work together. It is important to create awareness about the consequences of pollution so that people become conscious of the need to deal with this problem.
The country needs robust environmental laws for solid waste management and their efficient implementation:
- Pakistan has responded to its environmental problems by developing laws, establishing government agencies and accepting technical assistance from donors, including the World Bank. Despite this, the response remains fragmented and environmental institutions, laws, and other initiatives do not solve the whole problem
- Environmental legislation is still not immature in Pakistan, especially in comparison to the developed world. For example, there are no National Quality Standards for Solid Waste Management (SWM)
Install Waste Disposal Facilities
There is lack of waste disposal facilities in the country. Currently, individuals dispose of wastes by throwing away plastic bags, wrappers, fruit peels, cigarette butts, etc. in public places. Following must be a course of action to deal this issue:
- Littering spreads pollution and ends up clogging drains and causing sanitation problems, this can be controlled by making roadside dustbins or proper disposal of waste at home
- If proper waste management is practiced, this waste could be converted into useful products
The best way to reduce waste is not to produce it in the first place. Everyone should try to reduce his/her consumption of goods as much as possible. For example, choose products with minimum packaging and instead of accepting plastic bags when shopping, use cloth/canvas bags.
Items should not just be thrown away after use if they can be used again. It will reduce of waste and better conservation of resources. Items like glass jars, bottles, and plastic bags can be reused.
Recycling results in creating new things from already used items. Almost 20-30 percent of MSW contains materials which could be recycled. For instance:
- Paper can be re-pulped and reprocessed into recycled paper, cardboard and other paper products
- Broken glass can be crushed, re-melted and made into containers, some forms of plastic can be re-melted and fabricated into carpet fiber or cloth
- Food wastes and yard wastes can be composted to produce fertilizers and soil conditioners