Problem

Quebec City, a UN World Heritage Site, decided to co-digest sludge from its wastewater treatment plant with source-separated food waste to generate renewable natural gas (RNG). The RNG plant has a total capacity of 182,600 tons per year, specifically 87,000 tons of food waste source-separated by citizens and 96,000 tons of wastewater sludge. One of the challenges was to produce high quality solid and liquid byproducts that could be recycled and generate additional revenue.

Solution

One of the critical pieces of equipment in this installation is without doubt the rotary press technology, developed and manufactured by Fournier Industries. Quebec City has purchased six units of the eight-channel model. A total of 48 dewatering channels will separate the solid fraction from the liquid fraction, enabling both products to be recycled. The filtrate from the Fournier press is so clean that the liquid digestate is transformed into ammonium sulfate, a liquid fertilizer. The biosolids will be used for land application or as soil amendment.

Results

The plant began receiving organic waste in the spring of 2023. "The tests of the rotary presses have so far met our expectations, as it's a high-performance piece of equipment that's easy to use and maintain. They add robustness and reliability to our process,” says Erick Pelletier, operations superintendent.

Learn more at www.fournierdewatering.com or call 800-463-6328

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