In order to comply with the requirement for secondary treatment, a sewage treatment plant located at Remmen in Halden municipality shall be upgraded. This implies that the existing treatment plant must be reconstructed in such a way that a biological treatment plant and a new separation level can be included. In addition, the capacity shall be increased from current 30 000 pe to 42 000 pe. The contract also include the construction of separate biogas plant for treatment of sludge intended for biogas production. This contract involves electro technical installations.