MacLaren Industries' kraft pulp mill, located in Thurso, Quebec was built in 1958 and used only a primary treatment process for treatment of its pulp waste until the mid 1990s. It was at this time that more stringent effluent requirements for BOD5 were defined for discharge into the nearby Ottawa River. To meet the new requirements and to make a commitment in protecting the environment, MacLaren decided to employ a secondary treatment process.
In 1995, MacLaren installed (41) 75 HP Aqua-Jet® surface aerators in an aeration basin to biologically treat its pulp waste. Six 75 HP ThermoFlo® surface spray coolers were also installed at this time in an adjacent basin to cool the pulp wastewater prior to biological treatment.
Aqua-Aerobic Systems equipment was chosen by MacLaren because of its reputation for efficiency and economical operation. It also was highly recommended by other pulp mills already employing Aqua-Aerobic equipment. MacLaren's new treatment process has enabled the plant to consistently meet effluent requirements and reduce pollution into the Ottawa River.
MacLaren's kraft pulp mill currently produces 238, 000 metric tons of pulp annually. This includes hardwood pulp and four specialty pulps, which are used to produce high quality papers such as parchment and photographic.