2.1 Global sustainability through customised local solutions – recycling and resource efficiency
Around a billion people still have no access to clean drinking water, and around 2.5 billion are without regulated wastewater disposal. The 2002 UN summit in Johannesburg highlighted the huge importance of drinking water supplies and wastewater disposal: the proportion of people having to live without clean drinking water and basic sanitation is to be halved by the year 2015. A simple direct transition of our methods to affected areas will not work as demographic change is storming ahead; adapted and efficient technologies and concepts are therefore required.
Designed decades ago for a much greater consumption of water, conventional, central supply and disposal systems depend on a high flow of water. However, household water consumption in Germany has been decreasing for years now, and the country’s demographic change suggests that this trend is set to continue further over the next few decades. To generate the pressure required to prevent solids from being deposited in the sewer systems, many areas are already having to pump in additional water. Smaller, decentralised concepts that can adapt to changing needs are therefore essential for the future.
Areas with a lack of water and ecologically sensitive regions can also implement customised, decentralised procedures so the available resources are used efficiently. However, this approach requires the entire local water system to be considered as a single entity, from water collection, treatment and distribution through to wastewater cleaning and recycling. Through integral examination and management, household wastewater can be treated and used as process water, and solids can be processed and used as fertiliser or converted into biogas for energy. Numerous projects funded by the Federal Ministry of Education and Research (BMBF) have investigated how tried-and- tested methods can be combined on site to form system solutions.
Example of China. “Semi-centralised”: this was the name given to a structure extending beyond individual building units, thus different from conventional centralised solutions. The “Semizentrale Ver- und Entsorgungssysteme für urbane Räume Chinas” project (semi-centralised supply and disposal systems for urban areas in China) primarily investigated the potential of this approach in China’s large, fast-growing cities (project 2.1.01).
Example of Germany. The “Sanitary recycling Eschborn” (SANIRESCH) project focussed on how to reduce water consumption for toilets and how the resultant urine water can be used in an environmentally compatible manner (project 2.1.02). The KOMPLETT project (2005 to 2009) was able to demonstrate that reusing all domestic wastewater and solids of a high yield density (e.g. in hotel complexes) could be made economically viable (project 2.1.03, Development, combination and implementation of innovative system components of process engineering, information technology and sanitary equipment to create a sustainable key technology for closed-loop water systems). “Production integrated measures for environment protection in hotel and catering industry in special consideration of existing built volumes” investigated how the concept described in its title could be implemented (project 2.1.04). “Recycling of Phosphorus – Ecological and Economic Evaluation of Different Processes and Development of a Strategical Recycling Concept for Germany” (PhoBe) is a project funded by the BMBF to see how scarce phosphorus can be efficiently recovered from effluent sludge; the researchers are also determining the production costs of the procedures involved (project 2.1.05). When it comes to connecting new building developments, local areas need to consider whether to expand existing sewer systems. At a new building development in Knittlingen near Pforzheim, a “Decentralised Urban infrastructure System 21” (DEUS 21) was drafted and implemented (project 2.1.08).
Example of Vietnam.The issue of resolving contamination through mineral fertilisers and human excrement is being investigated under a German-Vietnamese project called “Closing Nutrient Cycles in Decentralised Water Treatment Systems in the Mekong-Delta – SANSED” (project 2.1.06).
Example of Turkey. Environmentally friendly waste and wastewater disposal or energy supplies are a rarity among tourist facilities. One solution could be “Integrated modules for high-efficient wastewater treatment, solid waste disposal and regenerative energy production in touristic resorts” (MODULAARE) (project 2.1.07).
