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Sub-project 2a

Decoloration of blackwater (cotreated with process water from anaerobic waste treatment) to be reused (2009 - 2010)

Concept and implementation of semicentralized supply and disposal centers include the separation of wastewater partial flows already during accumulation in the residence units. Greywater and blackwater are conveyed in separate pipes to the supply and treatment center where they are treated in separate treatment units. In addition, the generated sewage sludge is stabilized in digestion tanks together with organic waste, and biogas as energy resource is produced. The integrated treatment of organic waste and wastewater enables the energy-autarkic and thus independent operation of the whole supply and treatment center.

Suitable treatment processes for these wastewater partial flows are, for example, the activated sludge process, membrane bioreactors and the biofilm process, as they are used in the treatment of municipal wastewater. Within the frame of the research project "Semicentralized supply and disposal systems for urban areas in China, funded by the BMBF (Federal Ministry of Education and Research), sub-project 2 (project funding reference number 02WD0607), it was demonstrated that greywater can be treated sufficiently to reach the Chinese standards on the reuse of treated wastewater e.g. for toilet flushing. Thereby, experiments in semi-industrial scale, applying different processes, such as "Biological Aerated Filters (BAF)", "Membrane Bioreactors (MBR)" and "Sequencing Batch Reactors (SBR)" have been carried out.

The main focus of sub-project 2a, part C, is on the advanced treatment of blackwater. Biologically treated blackwater may still be colored, thus preventing its direct intra-urban reuse and creating acceptance problems. These problems are further aggravated when process water from the anaerobic/aerobic treatment of sewage sludge and organic waste is cotreated, as the coloration of the treated water is intensified. Hence, the research project focuses on the investigation of technical solutions towards the decoloration of treated blackwater containing significant amounts of wastewater from sewage sludge and organic waste treatment. Besides the required degree of decoloration (depending on the intended application), robust, reliable, and low-maintenance processes with low operational costs are decisive factors when selecting the decoloration method.

Duration: 04.2009 - 10.2010Project funding reference number: 02WD0989