Design of Zebra Mussel Control Measures for Hydro-Electric Power Projects

Zebra mussel, Dreissena polymorpha, is a biofouling organism that lives generally in freshwater ecosystems. Zebra mussel infestation has occurred at various freshwater structures and systems including raw water intakes, industrial and domestic distribution pipelines, and hydropower facilities at its native regions as well as distant locations. A study was conducted to perform risk assessment and to develop preventive measures for zebra mussel infestation at a planned hydroelectric power plant (Alpaslan II HEPP) in southeast Turkey. Zebra mussel is native to Anatolia region and existing hydropower facilities have significantly been affected by mussel infestation. The risk assessment was conducted by considering effects of various factors on zebra mussel infestation. The factors included environmental conditions, factors related to materials used in construction of various components of a HEPP as well as the susceptibility of various components to infestation due to routine operation of a facility. Quantitative study of head loss due to major infestation for Alpaslan II HEPP indicates approximately 4% reduction in power generation. A two-step process is proposed to prevent mussel infestation at hydroelectric power plants. The method makes use of the water hammer effect that occurs during rapid shutdown of the turbine combined with an automated system for providing chemicals to the power plant water to remove and kill zebra mussels associated with various components of a facility. The proposed system constitutes a proactive-reactive chemical treatment system.