Experts from the Bioenergy Association of Ukraine, as a part of a Ukrainian delegation, visited Augsburg (Germany) and got acquainted with the waste management system.
The trip "Modern technologies and conceptual solutions for the waste processing industry" was held on May 20-24 in the cities of Bavaria within the framework of the "Bayern-fit for partnership" program of the Bavarian Government. Organizers: em&s and Solid waste consult Ukraine-Bavaria. Funding: Bayern International.
Waste in the region of Augsburg is separated into several containers. For recycling comes mostly brown (organic waste) and gray (unsorted residues) containers. The content of the gray container – burned, brown content – is fused to produce biogas. Paper, glass, plastic, packaging are utilized with the help of private companies.
Recycling in Augsburg is a comprehensive solution for one million inhabitants
The processing of organic and unsorted waste is organized by the non-profit municipal company AVA, that is established in 1991 by several municipalities, the main founder is Augsburg (280 thousand inhabitants). The services of the company are used by about one million inhabitants on the territory of 4880 km2.
|Fig. 1 Entrance of cars with waste on the territory of the complex||Fig. 2 Loading waste (unsorted residues) for incineration|
Incineration of waste
The company recycles 350,000 tonnes/year of waste, of which 250,000 tonnes/year is combusted with heat and power generation (Fig. 3,4). Heat is supplied to the district heating network, used at the biogas plant of the company, a certain part is supplied to remote consumers by auto transport.
The burning temperature of the municipal solid waste (MSW) is at least 850 оС. After combustion, five-stage flue gas cleaning is used: electrofilters, water scrubbers, denitrification, filter with activated carbon. As a result, there have been no cases of exceeding the maximum allowable concentrations in flue gases during all exploitation periods.
After incineration 61,000 tons/year of slag is used to fill old salt mines and in road construction.
Also, 7,000 tons/year of metals are pre-selected from slag and bring an additional income of 1 million euros per year.
The company has two furnaces for burning medical waste (3500 tons/year). Medical waste is collected in special sealed containers and burned with them.
|Fig. 3 The crane operator loads the waste (unsorted residue) for incineration||Fig. 4 Remote control of waste incineration|
Biogas production by organic waste fermentation
From 105,000 tons/year organic (food and garden) wastes biogas is generated and then, after purification and membrane enrichment, – biomethane. Biomethane is fed to gas filling stations through gas distribution networks and used as motor fuel. The resulting amount of gas is enough for 3800 cars to run 15,000 km for 1 year.
Fermentation of organic waste is organized in thermophilic mode. For this purpose, 3 reciprocating reactors, with a slow mixing, working in parallel are used (Fig. 5.6). Reactor's volume is 1600 m3 each. To heat the reactors, the heat generated by the combustion of waste is used. Reactors are connected to a universal common gas storage holder. The waste is in the reactor for 18-20 days.
|Fig. 5 The feeding system of biogas reactor||Fig. 6 General view of the biogas installation|
The regenerated mass is divided into liquid and solid fractions. The liquid is used as a fertilizer for irrigating agricultural fields (28,000 tons/year). Solid is subjected to additional aerobic treatment and after 20 days of stabilization and final sifting is converted into commodity compost (16,000 tons/year) (Fig. 7).
Fig. 7 Commodity compost
So, conditionally zero waste treatment is organized in Augsburg. Separately collected organic waste is fermented to produce biogas, and the remainder is used as a fertilizer or a commodity compost (regulatory contamination of raw materials for compost 2-3%). Unsorted residual waste is burned, and the resulting after-burning slag is used for road construction or in salt mines, thus reducing the need for disposal in the landfill.More about the problem of recycling the municipal solid waste can be found in the UABio position paper (2019) here.Read also: UABio at the largest municipal solid waste landfill in Ukraine.