Master Thesis on blackwater treatment and nutrient recovery
Lisa Gren, who has studied Natural Resources Engineering with a focus on Environment and Water, has recently published her Master Thesis The mass balance of compounds in source-separated blackwater treatment at RecoLab, Helsingborg. The purpose of the work was to investigate the treatment and nutrient recovery of source-separated blackwater at RecoLab through the calculation of mass balances.
The mass balances showed that the biogas production at RecoLab was functioning well, with a production of approximately 150 m³ CH₄/week or 88 kWh/PE/year. A large fraction of the COD was reduced during anaerobic digestion. Nutrient recovery in the form of sludge and struvite (a recovery of 27% of total phosphorus and 2.5% of total nitrogen) was affected by the struvite precipitation process, which had a low separation rate. The mass balances indicated significant losses of total phosphorus and total solids during the struvite precipitation process. To achieve a satisfactory nutrient recovery, the separation and collection of struvite should be improved. The thesis also showed that both the sludge and the struvite had low metal content (13 and 0.68 mg Cd/kg P, respectively).
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