The Hindu Business Line : Municipal solid waste disposal

It was a revelation last week when I visited two re-cycling plants in Germany. The first was RWE Umwelt’s Contherm pyrolysis plant adjacent to the coal-fired power station at Hamm-Uentrop, where Berthold Bonekamp, my good friend and member of the Board, conducted me personally. And, the other was Sustec Verwertungs-Zentrum (SVZ) (recycling centre) plant owned by Global Energy for recycling of waste by gasification, in a town called Schwarze Pumpe.

It appears clear that high grow rates are leaving Urban India with a massive waste disposal problem. Consumption linked to per capita income has a strong relationship with waste generation; so India’s waste disposal problem will only increase in the coming years. Europe has solved the problem “bottom-up”, responsibility being shared by the many stakeholders, including the citizens, product manufacturers, consumers and the recycling industry, trade, municipalities.

The National Waste Management Act of Germany stipulates recycling under ecological and technical aspects as against mere landfill disposal. Wastes with high calorific values have to be recycled either by using thermal degradation of waste, also known as ‘pyrolysis’, or by gasification.

Pyrolysis

In unit C of the power plant ‘Westfalen’, it was explained to me that for RWE-Power Company with a capacity of 769 MW, about 10 per cent of the required hard coal is replaced by a special substitute fuel obtained from pyrolysis of waste, thus saving fossil sources of energy. The wastes treated in the ConTherm plant include residues from the waste paper treatment and paper production, packaging wastes, mechanical/biological domestic refuse, high caloric industrial wastes.

Gasification

When I visited the SVZ-plant for recycling of waste by gasification, in East Germany, I was told that around 500,000 tonnes of solid wastes were treated with three different systems of gasifiers and produced approximately 100,000 tonnes of methanol (CH{-3}OH). The methanol is marketed in chemical and plastic industry at market prices, where the methanol is used predominantly for the production of new plastics. With this system — gasification and methanol production — the organic components of wastes are converted into new raw materials, which can be used without restrictions for different new products. The wastes treated in the plant are sewage sludge, shredder-light-fraction, plastic wastes, contaminated wood, electronics wastes, sorted fractions of domestic refuse (dirty packaging wastes), tar sludge, lacquer and paint waste, liquid and pasty industrial wastes.

A look at what happens to waste other than those mentioned above, at the 800 public waste sorting and management organisations, about 120 waste incineration and mechanical-biological treatment plants, about 60 cement works and coal-fired power plants for the co-incineration of substitute fuels and over 40 existing and planned substitute fuel power plants across the entire federal territory.

Paper

Currently, household paper in Germany and most of Western Europe is collected directly from containers stationed in front of each house or apartment block. Newspaper, wrapping paper, shredded documents, and cartonages are thus easily incorporated into the recycling system.

While domestic household paper is primarily used for lower class ingredients, it is reprocessed to obtain packaging or wrapping paper. Office paper on the other hand is a untainted raw material and, therefore, utilised to produce high quality paper products. Thus, both mechanical and manual pre-selection is done at “waste sorting centres” all over Germany. They make sure that the material fed into the complex recycling process is kept at a preset qualitative level.

Glass

Glass is best recycled on the bases of its colour. In Germany and most of Europe, separation occurs primarily in two categories; that is, of clear and coloured glass and is done at every home. The network of collection station covers density of about 100 families per collection site. The delivered material is first pre-selected manually to remove unsuitable constituents (metal caps, ceramic parts, etc.). Before the glass is introduced into the smelter, it has to pass through a crasher and breaks it into pieces not larger than 15mm. An attached metal separator and an aeration tank extract any non-glass particles that have been overlooked.

Plastics

In Germany, every home or apartment block is the collection point. Due to the vast diversity of this material, trained staff are used to manually sort between reusable (thermoplast) and unusable plastics (thermoset) — besides the other stuff that does not at all fit into these categories. Though manual screening is monotonous, separation is done with care to obtain a constant output of reusable substances. Extra caution is taken at the sorting centres to avoid injuries due to irresponsible disposal of hazardous waste (syringes, glass, and other bio-hazardous contaminates), which may harm workers’ health. The reusable and more homogenous material is packed and piled before being forwarded to appropriate processing plants.

Metal

With the available modern separation technologies, household-metals collection does not require to be split into its respective fraction at the collection site (Fe, Al, etc.). Automated separation devices and powerful electromagnets, separate the ferromagnetic fraction from the non-magnetic components, while high-frequency eddy current inducers enable separation of the para- and dia-magnetic fractions. The separated fractions are delivered to suitable smelters where they are reprocessed to new materials. The slag generated during the melting process is disposed off in appropriate landfills.

Organic waste

Every home in Germany has organic waste collection bins. Collection at the site of consumption guarantees a quality product of supreme purity. This purity though is achieved because every individual and family member diligently follow the system and act responsibly by avoiding deliberate contamination. The containers filled with organic debris are collected on a weekly basis. To slow down any fermentation processes taking place within the container, most households lower the level of humidity by wrapping a day’s portion of organic material in newspaper before disposing it into the bin. Before the organic fraction is fed into a shredder, the material is checked manually for any major disturbing constituents and major contaminants. After the shredding process, the organic matter can be processed in various ways (either aerobically or an-aerobically). The humus produced is safely used for re-greening denuded areas, in agriculture, or to enrich existing soils.

Batteries

Not a single battery is dumped into the common household rubbish can. They are returned either to the dealer or to the recycling stations located in any major German city.

In conclusion, the ‘mission’ in Germany is that by 2020, all the municipal solid waste can be fully utilised, recovered and/or recycled in an environmentally-friendly manner, rendering any further landfilling of MSW unnecessary.

(The author is former Europe Director, CII, and lives in Cologne, Germany. Feedback may be sent to mohan.murti@t-online.de)

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