Turning wastewater treatment pipes into micro-hydropower plants

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While some have focused on how to use waste product sustainably, Hatch saw a very different opportunity at Halton, Canada – setting an innovative example that may be replicable around the world.  

Global experts have issued an Award of Excellence to Mid Halton Wastewater Treatment Plant in Canada, for adopting world-leading technology to turn an outflow pipe into a micro-hydropower plant.

Sited at an elevation 40m higher and 4km away from Lake Ontario – into which treated water is released – Hatch worked with turbine suppliers to develop a micro-hydro power arrangement that could be located within the limited space in the shaft available beside the drop structure.

Performance matters
While installing renewable power generators like this is a remarkable innovation, it needed to be done without hindering the purpose of the plant – treatment and release of wastewater.

The micro-hydropower system used at Halton manages that balance, not impacting on the plant’s efficiency or capacity for treating water while generating sufficient renewable energy to make the investment worthwhile.

Based on the head available at the drop structure, and on the expected flows at the facility, a 700kW turbine was selected to generate electricity “behind the meter”, meaning it would be used within the plant rather than sent to the grid. Since its installation, it has reliably produced more than 3,000kWh of energy each day – significantly reducing the plant’s need for energy from other sources.

To achieve this remarkable outcome, extensive 3D modelling was undertaken to ensure the facility would not be damaged during surge or high-use conditions. The project also involves the first known use of piped venting for a baffle drop system – for which Iowa Institute for Hydraulics Research had to be consulted for validation.

The Award of Excellence has been given, as part of the 2021 FIDIC Project Awards, to eight global projects on the basis of sustainability and impact, and Halton is now a case study for helping the water industry to reduce its energy impact on the climate.

This project was nominated by Hatch, Canada. 

Micro-hydropower within wastewater outflows could be replicated around the world.