Wastewater and nutrient recycling

Optimization of Wastewater and Nutrient Recycling in Braunschweig

Project Funding

Abwasserverband Braunschweig

Project Duration

2009-2013

Project Partner

Abwasserverband Braunschweig

Contact Person

Dipl.-Geoökol. Daniel Klein

Objective of the Research Project

The wastewater irrigation system of Braunschweig is an exceptional system for the agricultural reuse of wastewater and sludges. All produced sewage sludges are reused after digestion (and biogas production), either by adding them to the irrigation water or by marketing of the dewatered sludge as fertilizer. Treated wastewater is reused as well either for irrigation of agricultural fields or for soil treatment on the irrigation fields.

The objective of the research project is to develop optimization concepts and to evaluate and implement these concepts within the entire system. The basis for the development of the optimization concepts is an extensive materials flow analysis of the system and an investigation of the interaction between the various components.

Starting points for a system optimization are among others

• separation of water and nutrient cycles in order to harmonize nutrient supply and agricultural nutrient demand, thus reducing costs for fertilizer and saving nutrients for other uses,

• separate treatment of process water in order to improve nutrient recovery as well as marketing of produced fertilizing substances and

• cultivation of energy crops on areas of the irrigation field which have been fallow so far. These energy crops can be used as co-substrates in the digestion process which will increase biogas production and release nutrients into the sludge cycle.