We recycle this enormous volume of sewage sludge to recover materials or energy - and all this in 9 European countries
An ever increasing number of local authorities are finding out that innovative material flow management is an integral part of water management thanks to their work with REMONDIS Aqua. A selection of examples have been listed below which illustrate this type of collaboration.
In 2010, we optimised the material flow concept used by Energieversorgung Sylt (EVS) at its Westerland sewage treatment plant. One of the most challenging features of this project: transporting the sewage sludge by auto train to the mainland. The material is reused on farmland in the state of Schleswig-Holstein. Whenever necessary, sewage sludge that is not suitable for materials recycling can be disposed of in a 'mono-incineration' plant where it is used to generate energy. Primary energy sources are not required for this process. Together with the REMONDIS branch on Sylt, we are able to provide EVS with a flexible service collecting and taking away their sewage sludge whenever they need us to.
Since 2011, we have been responsible for carrying out all central material flow management activities, including transport and recycling, on behalf of the municipal waste management company, Klintholm I/S. The 10,000t of sewage sludge generated each year are transported by road and rail to power plants where they are used to generate energy – acting as a substitute fuel, therefore, and helping to considerably reduce consumption of fossil fuels. Having just one company organise all activities not only saves time but also money and guarantees a reliable and top quality service.
We have been responsible for transporting and recycling the almost 80,000t of sewage sludge generated each year by the city's five sewage treatment plants on behalf of Stadtentwässerungsbetriebe Köln (StEB Köln) since 1998. Stadtentwässerungsbetriebe Köln is – with REMONDIS' support – continuously working on optimising its processes. The advantages for StEB Köln are obvious: the complete range of services is provided by REMONDIS – from the in-house logistics, to the transport and recycling of the material. An unusual situation can be found at the main sewage treatment plant in Cologne (one of the largest facilities in the state of NRW with 1,570,000 population equivalents) as the sewage sludge has to be collected and transported away for recycling 365 days a year. 75% of all the sewage sludge generated in Cologne is incinerated and transformed into electricity and steam i.e. it is used for energy recovery; 25% is returned to the natural cycle as a fertiliser and supplier of humus. Together with StEB Köln, therefore, REMONDIS is helping, on the one hand, to reduce consumption of fossil fuels and, on the other hand, to actively conserve natural reserves of phosphate.
A.I.D.E. is an inter-municipal association that has been responsible for treating wastewater and supplying drinking water to the districts in the province of Liege (84 municipalities) since 1976. REMONDIS Aqua is the company in charge of centrally managing material streams. REMONDIS Aqua has been recycling practically all of the sewage sludge generated in the province of Liege since 2014. In order to ensure that the company can provide its services at all times, it has secured contracts with recycling facilities close by so that it is able to recycle more than 700,000t per year and transform these volumes into energy.
Wirtschaftsbetrieb Mainz is an independent public law institution and operates the sewage treatment plant in Mainz-Mombach, the largest in the state of Rhineland-Pfalz. This facility accepts wastewater from approx. 250,000 local inhabitants as well as from commercial and industrial companies located in and around Mainz. REMONDIS Aqua has been responsible for transporting and recycling the sewage sludge (dewatered and dried forms) as well as the screenings, grit chamber residue and sewer sand since 1997. All together, this makes up a volume of over 12,000t of residual materials every year. All of the sewage sludge and screenings are used to recover energy. The grit chamber residue and residue sand from the sewer system are sent for materials recycling. By drying the majority of the sewage sludge and transforming it into energy, Wirtschaftsbetrieb Mainz is – together with REMONDIS Aqua – making an active contribution towards reducing the demand for fossil fuels.
The owner-operator business, Stadtentwässerung und Umweltanalytik Nürnberg (SUN), runs two sewage treatment plants in the City of Nuremberg and ensures that the wastewater generated by the more than 530,000 local residents and the many industrial businesses based there is collected, transported and treated efficiently and effectively using methods that make good business and environmental sense. REMONDIS Aqua has been responsible for centrally managing the material streams at the facility, one of the largest in Germany, since 2011. It handles the transport and complete recycling of the sewage sludge on behalf of Stadtentwässerung und Umweltanalytik Nürnberg. Up to 10 articulated trucks a day ensure that the annual volumes of 40,000t of dewatered sewage sludge are transported safely to the recycling facilities. Five power plants are used to transform the material into energy guaranteeing a reliable service whenever it is needed.
The Bändlegrund in Weil sewage treatment plant on the Rhine has been accepting and treating municipal and commercial wastewater from the towns of Weil am Rhein, Lörrach and surrounding districts since 1957. Extended to cover 290,000 population equivalents, it is now also able to process the wastewater from the Unteres Kandertal wastewater association, the district of Efringen-Kirchen and other industrial companies located in its catchment area. REMONDIS Aqua has been carrying out material flow management services at the Bändlegrund sewage treatment plant on behalf of its customer, Wieseverband Abwasserverband Lörrach, since 2012. The solar-powered sewage sludge drying facility located at the sewage treatment plant dries a large volume of the dewatered sludge generated there - a process which increases the calorific value of the material and reduces its overall weight. Each year, 4,500t of dewatered and 2,100t of dried material are produced at the plant which are used to generate energy at seven power stations.