Towards carbon neutrality and circular economy: an innovative combination of enhanced biogas production and nutrient recovery from sludge dewatering liquor at a municipal wastewater treatment plant in Germany

Autor: Anne Kleyböcker, Fabian Kraus, Stefanie Meyer, Janina Heinze, Franziska Gromadecki, Christian Remy
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Water Science and Technology, Vol 90, Iss 3, Pp 680-695 (2024)
Druh dokumentu: article
ISSN: 0273-1223
1996-9732
DOI: 10.2166/wst.2024.247
Popis: An innovative circular economy (CE) system was implemented at the wastewater treatment plant (WWTP) in Brunswick. The performance of the CE system was evaluated for 4 years: the thermal pressure hydrolysis enhanced the methane production by 18% and increased the digestate dewaterability by 14%. Refractory COD formed in thermal hydrolysis and increased the COD concentration in the WWTP effluent by 4 mg L−1 while still complying with the legal threshold. Struvite production reached high phosphorus recovery rates of >80% with a Mg:P molar ratio ≥0.8. Nitrogen was successfully recovered as ammonium sulfate with high recovery rates of 85–97%. The chemical analyses of secondary fertilizers showed a low pollutant content, posing low risks to soil and groundwater ecosystems. The total carbon footprint of the WWTP decreased due to enhanced biogas production, the recovery of renewable fertilizers and a further reduction of nitrous oxide emissions. Using green energy will be crucial to reach carbon neutrality for the entire WWTP. HIGHLIGHTS Full-scale implementation of a circular economy approach at a municipal WWTP.; 18% increase in methane production due to thermal pressure hydrolysis.; High recovery of struvite and ammonium sulfate from sludge liquor.; High quality of secondary fertilizers with low pollutant concentration.; Decrease in carbon footprint due to energy and fertilizer recovery and lower nitrous oxide emissions.;
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