The five phases of waste management
„Waste management is not easy to understand. Different stakeholders have to show their commitment in very different areas for the waste management sector to develop. That takes time. In Germany, we started in 1970 and still haven’t finished. That is why German experts have developed the Five Phase model. It aims to help to establish the waste management situation in a region, so that the future course of action can be agreed. In a given country, the model need not develop in the strict sequence of phases and transitions are often fluid. If we regard it as a basis for discussion, it can help in reaching a better understanding of the many aspects of waste management.“
(Naemi Denz, Managing Director VDMA industry association for waste management and recycling technology)
Phase 1: Extensive uncontrolled dumping
In many countries waste is dumped on uncontrolled tips; there is no properly managed waste collection. At best, recyclable materials such as metals and plastics are collected by the informal sector and re-enter the resource cycle through a number of stages.
People live on the rubbish heaps in appalling conditions. Basic principles of urban hygiene and environmental conservation are ignored. Rubbish is often used for heating and cooking with all the negative consequences for human health.
Phase 2: Reliable collection and better landfill sites
Introducing systematic, regulated and reliable collection and establishing properly managed landfills comprises the first step in developing the waste management sector. Conveniently located transfer stations facilitate cost-efficient transportation of waste.
It is crucial that collection is carried out efficiently since this is the most expensive element of waste management. However, along with the sorting processes, it also offers the greatest employment potential. It is important to identify the ‘right’ collection system for each town or community and its particular circumstances.
Elements of a circular economy can be implemented even in this early phase, for example with separate collection and hand-sorting of recyclable materials. Simple composting facilities for park and market waste, using mobile equipment, mark the start of organic waste recycling.
Phase 3: Separate collection and sorting
Separating and collecting in several containers forms the basis of high-quality sorting and high-grade recycling processes2. Efficient purpose- built vehicles with compactors are introduced for collecting the waste. The first optical separators make it possible to produce high-quality monofractions. A downstream, secondary industry develops as the supply of inputs becomes reliable. Increasingly, the industry adapts its processes to these materials. A significant number of jobs are created and waste management becomes part of industrial policy.
The sorting facilities contain mechanical separation stages, screens and separators and prepare material for more efficient hand-picking. The first elements of a trading system emerge for recyclable materials that meet industry demand and bring in revenue (such as metal, PET and paper).
Composting separately collected organic waste and extracting fractions with high-calorific value to generate refuse-derived fuel (RDF) leads to the emergence of new products for which there is increasingly a market.
Phase 4: Expanding the recycling industry
Modern sorting facilities produce high-quality monofractions from separated waste; these are prioritised for recycling. Processes to separate plastics and sort by colour are used. Compost and/or biogas are produced from organic waste in composting and fermentation plants. Residual waste undergoes energy recovery in incinerators or is treated in mechanical-biological treatment facilities (MBT). MBT extracts recyclable materials, delivers high-calorific fractions for energy generation and controls the decomposition of organic substances, which are mainly responsible for emissions from landfill sites – in particular landfill gas and leachate. Waste-to-energy facilities and waste biomass CHP plants replace primary fuels. This leads to a significant reduction in greenhouse gas emissions.
Phase 5: The circular economy – waste as a resource
In this phase waste is predominantly recycled or undergoes energy recovery; untreated household waste no longer goes into landfill. The high recycling rates achieved result in a functioning circular economy. Only small amounts of residual waste are landfilled and do not harm the environment. Preventing waste and taking a life-cycle perspective are underlying principles in all production processes and many consumer choices.