Waste Management, Recycling, and the Circular Economy

Waste management is the collection, treatment and disposal of waste to protect health and the environment, recycling is the processing of used materials into new products, and the circular economy is an economic model that aims to design out waste, keep products and materials in use for as long as possible and regenerate natural systems. In brief: the waste hierarchy ranks options from best to worst: prevent, reuse, recycle, recover energy and dispose. The world generates about 2 billion tonnes of municipal solid waste a year, and the World Bank expects this to grow to more than 3 billion tonnes by 2050 without action. A linear economy (“take, make, dispose”) wastes resources, and a circular one keeps them in loops.

Waste is a growing problem because of rising consumption and urbanization, but it is also a resource. This guide explains the types and amounts of waste, the waste hierarchy, how recycling and composting work, what the circular economy means, compares the options in a table, works through calculations, outlines the history and corrects common mistakes.

How much waste is there and what is it made of?

According to the World Bank’s What a Waste 2.0 report, the world produced about 2.0 billion tonnes of municipal solid waste in 2016, an average of about 0.74 kg per person per day, with a range from under 0.2 kg in some low-income countries to over 1.5 kg in high-income countries. Roughly 44% of this waste is food and green waste, and about a third consists of paper, plastic, glass and metal. Around a third of the waste worldwide is not managed in an environmentally safe way, but is dumped openly or burned, mostly in low- and middle-income countries, and it pollutes air, soil and water, blocks drains, spreads disease and releases greenhouse gases. Other waste streams include construction and demolition waste, industrial waste, hazardous waste and electronic waste (e-waste), which reached about 62 million tonnes in 2022, of which less than a quarter was formally recycled.

Plastic waste has drawn special attention. Global plastic production has grown rapidly since the 1950s, and according to the OECD, only about 9% of plastic waste is recycled, while a large share is landfilled, burned or leaks into the environment, including oceans.

What is the waste hierarchy?

1. Prevention (reduce): avoid creating waste in the first place, for example with less packaging and longer-lasting products.
2. Reuse: use items again, such as refillable bottles, second-hand goods and repair.
3. Recycle: process materials into new products, including composting of organic waste.
4. Recover: burn waste in plants that produce heat or electricity (energy recovery), or capture landfill gas.
5. Dispose: landfill or incineration without recovery, the least desirable option.

The higher on the list, the better the environmental outcome, generally.

How do recycling, composting and other treatments work?

Recycling needs collection, sorting, cleaning and reprocessing. Metals, glass, paper and many plastics can be recycled. Recycling saves raw materials and often energy: producing aluminum from recycled scrap takes about 95% less energy than producing it from ore. Problems include contamination, mixed materials that are hard to separate, falling prices for recycled materials and loss of quality (downcycling). Composting turns food and garden waste into compost, and anaerobic digestion produces biogas and fertilizer from organic waste. Landfill is the most common disposal method, and modern landfills have liners, drainage and gas collection, but old and open dumps release methane and leachate. Incineration with energy recovery reduces the waste volume by about 90% and generates energy, but needs air pollution controls and can compete with recycling. Informal waste pickers collect recyclable materials in many cities of the developing world, and often make a substantial contribution to recycling rates.

What is the circular economy?

The linear economy takes resources, makes products and throws them away. The circular economy, promoted by the Ellen MacArthur Foundation and by the European Union’s action plans, is based on three principles: design out waste and pollution, keep products and materials in use, and regenerate natural systems. In practice, this means durable and repairable design, modular products, standardized parts, leasing and sharing models (a product as a service), remanufacturing, refurbishing, recycling into high-quality materials and the use of renewable energy. Policies to support it include extended producer responsibility (producers pay for the collection and treatment of the products they sell), deposit-return schemes for bottles and cans, landfill taxes, bans on some single-use plastics, the “right to repair” and green public procurement. Critics note that a fully circular economy is impossible because of energy needs and losses, and that reduced consumption is also required.

Waste options compared

Worked example: waste per person and diversion rates

The values are hypothetical and illustrate typical calculations.

1. Waste per person: a city of 1.5 million people produces 1,800 tonnes of waste a day. Waste per person = 1,800,000 kg ÷ 1,500,000 = 1.2 kg per person per day.
2. Annual waste: 1,800 × 365 = 657,000 tonnes a year.
3. Composition: if 40% is food and garden waste, 20% paper and card, 12% plastic, 8% glass, 6% metal and 14% other, the shares add up to 100%. The organic waste is 0.40 × 1,800 = 720 tonnes per day.
4. Diversion rate: the city recycles 360 tonnes and composts 270 tonnes a day. The diversion rate is (360 + 270) ÷ 1,800 = 35%, so 1,170 tonnes a day, 65%, go to landfill or incineration.
5. Improved system: a program that collects food waste separately and raises the diversion to 55% reduces the disposal to 0.45 × 1,800 = 810 tonnes per day, a cut of 1,170 − 810 = 360 tonnes per day, or 31%.
6. Energy saved by recycling aluminum: making 1 tonne of primary aluminum takes about 15,000 kWh, and recycling takes about 5% of that, or 750 kWh. Recycling 1,000 tonnes saves (15,000 − 750) × 1,000 = 14,250,000 kWh.
7. Deposit scheme: a 0.10 deposit on 500 million bottles with a 90% return rate returns 450 million bottles, and unclaimed deposits are 50,000,000 × 0.10 = 5,000,000.

How has waste management developed?

Ancient cities such as Athens and Rome had rules for waste disposal. In the 19th century, urban epidemics led to public health measures, including organized collection and sewer systems in industrial cities. The first major incinerators and municipal landfills appeared in the late 19th and early 20th centuries. Environmental awareness in the 1960s and 1970s led to laws such as the US Resource Conservation and Recovery Act (1976) and, in Europe, a waste framework with a hierarchy (1975, revised in 2008). Recycling programs grew in the 1980s and 1990s, and in 2018, China’s ban on imports of most waste plastics shook global recycling markets. The Basel Convention (1989) regulates the movement of hazardous waste. The idea of the circular economy has been adopted in policy by the EU, China, Japan and many others in the 2010s and 2020s, and a global treaty on plastic pollution is under negotiation.

Which mistakes are common?

Mistake 1: Treating recycling as the best solution

Recycling is useful, but reducing and reusing are higher in the hierarchy because they avoid the energy and losses of reprocessing.

Mistake 2: Assuming that everything in the recycling bin is recycled

Contaminated or mixed materials may be rejected, and the actual recycling rate for items such as plastics is low.

Mistake 3: Believing that landfill is always harmful and incineration always better

Well-engineered landfills control emissions, and incineration needs controls and can discourage recycling. The best option depends on the waste type and local conditions.

Mistake 4: Thinking that the circular economy only concerns households

Most of the impact is determined at the design and production stages, so it requires action by businesses and governments, as well as consumers.