Grant: Collaborative Research and Development Grants

In this collaborative project, Dr. Fatehi of Lakehead University along with Dr. Fairbank and Mr. Dokis of Resolute Forest Products will investigate the application of fly ash in the wastewater system of the Resolute Forest Product mill in Thunder Bay, ON. Currently, pulping and bleaching effluents of kraft and TMP processes are mixed and treated in a wastewater system at Resolute's mill in Thunder Bay. These treatments are effective, but expensive. Furthermore, the costs associated with the handling of sludge produced in the wastewater system of the mill and the costs associated with the oxygen, nutrients and polymer usage in the wastewater treatment are challenges in the current configuration of wastewater system of the mill. On the other hand, fly ash is produced via incinerating bark and wood waste in one or more biomass boilers at Resolute's mill in Thunder Bay. Fly ash contains earth metal compounds as well as uncombusted carbon, and is presently land filled, which is an extra expense to the mill. In this proposed project, an adsorption process will be developed with the help of fly ash in order to treat the effluents prior to sending the effluents to a wastewater system. In this process, the organic materials dissolved in effluents will be adsorbed on fly ash. Then, the treated fly ash is separated by a filter or clarifier. The treated fly ash is sent to the power boiler for re-incineration, while treated effluent is sent to the wastewater system of the mill for the biological treatment. In principle, this new process will reduce the overall costs of the wastewater system as a lower load of organic compounds (compared to the current load) is treated in the wastewater system, which in turn reduces the sludge production rate. On the other hand, the treated fly ash that contains adsorbed organics will produce a net heat in the boiler. Resolute will benefit from this research program via assessing the possibilities for modifying its wastewater process to a more cost effective wastewater process. The technology developed in this work could be adapted by other pulp mills in Canada, which would help them reduce their wastewater operational costs and improve their overall competitiveness in the market.