BIOFOS is Denmark’s largest wastewater treatment operator, serving 1.2 million inhabitants in the Copenhagen metropolitan area via its treatment plants in Lynetten, Avedøre, and Damhusåen. BIOFOS utilizes the sludge generated from wastewater treatment for climate-friendly electricity, biogas, and district heating for the grid.
At the Lynetten plant, which is located close to the center of Copenhagen, wastewater is treated mechanically, biologically, and chemically to ensure it meets the strict standards set by the local environmental authorities. Organic matter, nitrogen and phosphorus are removed by biological treatment, and the excess phosphorus is removed from the water using chemicals. After treatment, the purified wastewater is directed to Øresund, the recipient water body that separates Denmark from Sweden.
Chemistry fine-tuning brings significant improvements
“We handle a 60/40 mix of bio-sludge and primary sludge which is processed in our on-site digesters to generate biogas for the city’s gas network and used for the district heating system,” says Peter Christiansen, Plant Manager at BIOFOS.
As well as looking to improve their sludge dewatering process to cut costs, the plant was also facing a challenge in the form of struvite build-up. This was causing problems in anaerobic digesters, pipes, pumps, and other equipment.
Based on a comprehensive analysis of the dewatering process at BIOFOS Lynetten, Kemira’s experts were able to identify where some fine-tuning to the chemistry would deliver significant improvements for the process.
“Because it’s a performance-based service, BIOFOS can rest assured that it’s also in Kemira’s best interests to ensure that everything is running smoothly.”