Micro-hydroelectric power generator for sewage treatment plants

Japan's Ricoh has developed a micro hydropower system that can be used in sewage treatment facilities, with sewage water serving as the source for low-head screw turbines.

The imaging and electronics company said that the electricity generated by the micro-hydro system could be used to power sewage plants.

“At this time, we have not conducted any testing regarding the combination of our system with PV or floating PV,” a company spokesperson told pv magazine. “However, we do believe that there is potential for PV to be combined with our system in the future, given the abundance of space available at sewage sites.”

The system features a water turbine that the company designed in collaboration with micro-hydroelectric system supplier Seabell Incorporated and the Kanazawa Institute of Technology. It consists of two generators mounted on a single unit, allowing efficient power generation. In addition, a waterwheel can be placed directly in the existing waterway, eliminating the need for a new bypass waterway. Ricoh provided its 3D printer technology to create the 3D-printed blades used in the system. These are made of biomass-derived materials.

“Compared to a water turbine made from commonly used 3D printer materials, our turbine is more than twice as strong as a metal turbine,” the spokesperson said. “Its strength was maintained even after being placed underwater for a long period of time and could be used for large-scale hydroelectric power generation.”

Ricoh conducted its first demonstration experiments at a sewage treatment plant in Shizuoka prefecture, Japan, in cooperation with Japan's Ministry of Land, Infrastructure, Transport and Tourism (MLIT). The project is designed to address several issues regarding the use of micro- hydroelectric systems at sewage facilities. These issues include low turbine efficiency, low output, high upfront costs, and the intensive use of human resources.  The electricity generated by the micro-hydro system can be used for backup power supplies at disaster-prevention centers in sewage treatment plants. 

“The system will initially be sold in Japan but we are continuously exploring the possibility of introducing our technology in other regions, including Europe, the United States, and emerging economies,” said the spokesperson.

In March, Ricoh launched a pico-hydro generation system that can be used with factory drainage systems and irrigation canals.

“The system can also be used in combination with photovoltaics and batteries to ensure stable power supply, ” a company spokesperson told pv magazine. “Depending on the amount of electricity generated, it can be used for IoT devices such as sensors, lighting devices, and charging systems.”