Irving Paper Inc. is a major producer of pulp and paper products in Saint John, New Brunswick, Canada. The St-John mill utilizes the TMP process to produce approximately 1 000 tons per day of pulp from 100% softwood.
The client's needs
The pulp and paper mill was aiming to reduce water usage by 6,000 m3/day in summer and 8 000 m3/day in winter by cleaning and reusing certain process water streams, including vacuum seal water (VSW) containing white fiber, and combining it with raw freshwater (RW) make-up. The mill goals were to reduce RW demand, improve process water quality, recover thermal energy and reduce wastewater flow.
The two Actiflo® package plants, built by Veolia Water Solutions & Technologies., are used to treat wastewater from the vacuum pump seal. In an innovative solution for paper mills, they produce high quality water for use in paper production by blending it with river water. Wastewater from the mill's vacuum pump seal water will flow to the Actiflo® units and be blended with raw river water.
The Actiflo® ballasted clarification process produces purified water at a rate of 3,400 USGPM. Energy is saved that used to be spent on reheating river water for use in the mill. Vacuum pump seal waste water from the pump has a turbidity of around 600-800 NTU, and Veolia's Actiflo® water treatment system will transform it, without filtration, to water with a turbidity of less than 1.5 NTU. "We provide major energy savings and high quality water by warming up cold water from the river for the mill," says Robert Lafond, Sales Engineer for Veolia.