A Significant Challenge

Despite communication campaigns on waste reduction and the promotion of recycling and composting, the vast majority of Quebec’s residual materials still end up in landfills. These sites generate wastewater that must be treated before being released into the environment. Specifically, landfill cells produce leachate with characteristics that vary from one cell to another on the same site; younger cells generate more heavily contaminated leachate, while older cells produce effluents with lower pollutant loads. This diversity of effluents on a single site means that wastewater treatment facilities are often sized for leachate from young landfill cells, making them oversized for the leachate generated by older zones. This results in inefficiency in operating existing treatment plants, which mainly use high-load, energy-intensive processes that require chemical usage.

Moreover, operators often face an overload of leachate volumes generated by their site, but few conventional treatment technologies allow for volume reduction. They are often forced to export their excess leachate to external treatment sites; a costly and environmentally unfriendly solution.

A Solution with Multiple Benefits

To address this environmental issue, Ramo has developed the Evaplant technology, a filtering plantation of willows. This technology, currently patent-pending, relies on the evapotranspiration of water, the degradation of contaminants by soil microbiota, and the absorption of certain pollutants by the willows. It allows for the treatment, valorization, and reduction of volumes generated by landfills, in addition to capturing carbon in the above-ground biomass. The technology also gives an agro-environmental purpose to landfill sites by valorizing the areas of cells that are no longer in operation (considered degraded). Evaplant reduces the volume of effluents discharged into the environment, directly improving the quality of water bodies.

The technology stands out favorably from conventional wastewater treatment solutions due to its low capitalization and operational costs (no chemical consumption and low energy consumption). Its main advantages include: extensive effluent treatment, vegetated and low-cost capitalization and operation, valorization of effluent resources by producing high value-added products (shredded wood mulch, fences, and noise barriers), partial or complete reduction of effluent volume through evapotranspiration, and carbon capture in the willow biomass. The secondary benefits of turnkey Evaplant projects include social acceptance, an engaging project for site employees, integration of a strong circular economy component, valorization of a degraded site, and increased biodiversity.

Willow filtering plantations, as executed by Ramo, include 15,000 to 20,000 willows per hectare. These willows are harvested every two or three years and regrow without needing to be replanted from the root system, which remains in place for the entire lifespan of the plantation (25 to 30 years). The plantation is irrigated using a process designed by Ramo specifically for wastewater irrigation. The precise control of loads sent to the plantation ensures that irrigation will not cause runoff outside the plantation or deep percolation. Unlike traditional solutions, the willow filtering plantation has a positive environmental impact.

The Evaplant technology is used to treat not only leachate but also composting water, mining effluents, and municipal water.