Co-treating municipal and industrial wastewater in Corner Brook

The City of Corner Brook (population: 19,547) will partner with Corner Brook Pulp and Paper to assess the opportunities to co-treat municipal and paper mill effluent (wastewater) in a combined process. Currently there is no treatment for most municipal wastewater in Corner Brook, which is discharged directly into the Humber Arm marine environment. The industrial effluent from the mill is currently treated through an activated sludge process. Corner Brook Pulp and Paper approached the city to study the feasibility of treating both effluents together for a net benefit to the city, the mill and the environment.

Studying co-treatment with the mill will determine whether true synergies would exist through working from a shared facility instead of two separate wastewater treatment plants. The scale at which co-treatment is proposed needs technical assessment to thoroughly understand the opportunities and risks. To that end, this study will investigate three different technical options for combining the two facilities. It will evaluate which option is most cost-effective and whether the effluent will meet the new environmental standards. The co-treatment technical options are as follows: 1) separate wastewater treatment plants on the same site with separate or combined effluent; 2) a mill wastewater treatment plant with mill effluent polishing at the city’s wastewater treatment plant; or 3) a fully combined wastewater treatment plant.

If implemented, the project will bring both municipal wastewater and the paper mill’s effluent within national environmental standards, resulting in significant improvements to the water in the Humber Arm.

Innovative aspect(s):

The flow rate of municipal and industrial sewage are roughly the same in Corner Brook. In most other examples of co-treatment, the industrial wastewater flow rate is much higher than that of the municipal stream. This study will help determine the feasibility of co-treatment where there is a more even ratio of municipal wastewater flow.

Co-treatment of municipal and industrial effluent would generate energy efficiencies due to reduced operating and equipment costs as well as the use of sludge as fuel. Approximately 3,000 wet tonnes of sludge per year are anticipated to be diverted from landfill and burned as fuel. Co-treatment would also eliminate the need to develop a new green site by utilizing the existing pulp mill area. It would also result in improved storage and process efficiencies with a combined effluent and one outfall.

Replicability:

Partnering of municipalities and industry in the treatment of wastewater is not a common practice in Canada but it is one with significant potential. This study will provide a template and base information for other jurisdictions to pursue their own initiatives on co-treatment of wastewater.

The results of the study will be disseminated through presentations at municipal and industry conferences. If co-treatment is found to be feasible in Corner Brook, this information could be useful to other communities with mill wastewater volumes comparable to their municipal flows.