Bekkelaget Sewage Treatment Plant

Bekkelaget is located in the beautiful Oslo Bay, and the sewage treatment plant is built in a cave. The sewage treatment plant is very sensitive to the requirements of influent water quality, and the effluent quality standard of the treatment plant is very high. The new bekkelaget sewage plant was implemented by PURAC AB from 1997 to 2001 and operated by PURAC operation company.

Bekkelaget sewage treatment plant was commissioned in 1999. It mainly increases the treated sewage volume and the treatment process to meet the discharge standard for the cleaner Oslo Bay. In order to improve the environmental quality along the Oslo Bay and develop more wharf areas, the sewage plant is built in the excavated caves. Purac jointly executed the turnkey project with a construction subcontractor. Purac is responsible for process design, construction drawing design, supply, installation, commissioning and training of mechanical equipment and automatic control instruments.

In this project, the average flow rate of the sewage plant reaches 1.4m3/s (120 ml/d), which is designed according to the population equivalent of 350000. The sewage treatment plant achieves 70% total nitrogen removal rate and 90% total phosphorus removal rate. Purac is fully responsible for the project continuation and 20-year operation management. The contract value amounted to SEK 460million.

The treatment process of bekkelaget includes mechanical and chemical pretreatment, biological treatment, advanced treatment, sludge thermophilic anaerobic and biogas purification as vehicle fuel. The effluent is discharged to Oslo Bay, and the treated sludge is used as fertilizer for farms around Oslo. The fuel produced is used for Oslo buses.