Salsnes Filter fine mesh sieves have been very successful for primary treatment of municipal wastewater. However, the market for primary treatment is very small and decreasing. To open up a significantly larger market it is necessary to qualify the Salsn es Filter fine mesh sieves for use in combination with biological processes. The primary objective is to develop fine mesh sieve systems for primary and secondary solids separation at wastewater treatment plants, with the intent to save resources by re ducing the cost and energy consumption for biological wastewater treatment and maximizing the energy recovery from the organic matter in the removed solids. Secondary objectives:a)Document the optimum particle removal in front of biological processes , for optimum biological treatment performance and recovery of resources from particles in the wastewater.b)Develop a fine mesh sieve system for achieving the optimum particle removal under secondary objective a) at the lowest possible use of resources. c)Develop a fine mesh sieve system for solids separation downstream of biofilm processes, providing good, economic and energy efficient solids removal in a small footprint.d)Large scale verification of the fine mesh sieve systems for primary and secon dary (biofilm) solids separation.The optimum particle removal from municipal wastewater in front of different biological processes is not known. It will require PhD level research to develop a sieve and control unit that can achieve the desirable parti cle removal. Separation of biofilm biomass will depend on the properties of the biomass, which will change with type of process, operating conditions and wastewater composition. Comprehensive testing will be required to gain the knowledge needed to devel op, design and operate fine mesh sieve systems for these purposes. Furthermore, independent R&D institution documentation from this project is crucial for the marketing and sales of these systems.