Zero Effluent System Significantly Reduces Boiler Maintenance and Feedwater Costs, 1996 Environmental Conference Proceedings

Louisiana Pacific’s BCTMP mill in Chetwynd BC, Canada commissioned their retrofitted zero effluent treatment system in July 1993. The mill originally started up in June 1991 with zeolite softened well water as the source for power boiler system feedwater. During the zero effluent plant modifications, the freeze crystallizers were converted to mechanical vapour compression evaporators. A thermal deactivation system preceded the evaporators to improve distillate quality and reduce scaling. Shortly after the start-up of the evaporators a program was implemented to use ‘mids’ distillate for boiler feedwater, which had typical conductivities of <20 µs/cm="" and="" ‹0.1="" hardness.="" recent="" inspections="" have="" shown="" that="" previous="" deposits="" on="" the="" power="" boiler="" are="" slowly="" being="" removed.="" chemical="" treatment="" costs="" have="" been="" reduced="" to="" 15%="" of="" comparable="" boilers="" operating="" on="" conventional="" water="" treatment="" programs.="" in="" preparation="" for="" the="" new="" recovery="" boiler,="" extensive="" chemical="" evaluations="" and="" studies="" were="" conducted="" to="" ensure="" that="" the="" trace="" volatile="" organics="" in="" the="" distillate="" did="" not="" have="" negative="" effects.="" in="" the="" fall="" of="" 1994="" the="" new="" recovery="" boiler="" was="" commissioned="" using="" ‘mids’="" distillate="" as="" boiler="" feedwater,="" with="" the="" same="" positive="" results="" being="" attained.="" since="" the="" implementation="" of="" the="" new="" zero="" effluent="" evaporators,="" both="" boiler="" systems="" have="" been="" operating="" with="" minimal="">