Review of remedial options for the Boat Harbour remediation project in Nova Scotia, Canada

Abstract

Boat Harbour, located in Pictou County, Nova Scotia, Canada has been receiving industrial effluent wastewater from a nearby kraft pulp mill and chlor-alkali plant for over 50 years. Before receiving industrial effluent wastewater, the tidal estuary was culturally significant to the nearby Pictou Landing First Nation community. The tidal estuary was known for its medicinal, recreational, ceremonial, and subsistence functions. Formally a 140-ha natural tidal estuary, raw industrial wastewater was discharged into Boat Harbour beginning in 1967. Since inception, effluent treatment has undergone several upgrades in aeration capacity within the Boat Harbour Effluent Treatment Facility (BHETF) until the cessation of effluent discharge in 2020. Fifty years of industrial wastewater effluent discharge has resulted in widespread inorganic and organic contamination of unconsolidated sediments and surface water. Primary contaminants of concern include metals, dioxins and furans, and polycyclic aromatic hydrocarbons. The province of Nova Scotia has committed to the remediation of the BHETF, estimated to cost over $292 million CAD. The goal of the remediation program is to return Boat Harbour to its natural state as a tidal estuary to restore the historical, traditional, and recreational uses of the land. Remediation components and alternatives were rated based on technical (26%), environmental (24%), economic (22%), social (14%), and regulatory (14%) weighted indicators. Criteria weighting for the five indicator categories was determined collaboratively with stakeholders. For each design component of remediation, a list of approaches was developed along with subsequent alternatives. Approaches and alternatives were screened to eliminate options that were not technically feasible or did not align with remediation goals. The remaining feasible concepts underwent detailed review and evaluation to select Qualified Remedial Options to be shared with stakeholders for input. 1 | INTRODUCTION Boat Harbour, recognized as one of Canada's most contaminated sites, is located in Pictou County, Nova Scotia (Province of Nova Scotia, 2020). The harbor was originally a 140-ha tidal estuary, known in Mi'kmaq as A'se'k, that flowed into the Northumberland Strait (Chaudhary, Walker, et al., 2020b; GHD, 2018a; Romo et al., 2019). In 1967, raw untreated industrial wastewater effluent from a bleached kraft pulp mill was discharged into Boat Harbour. Upgrades in 1972 by the province of Nova Scotia resulted in the construction of the Boat Harbour Effluent Treatment Facility (BHETF) to treat industrial wastewater effluent originating from a bleached kraft pulp mill and chlor-alkali plant (Hoffman et al., 2015). The bleached kraft pulp mill operated from

Contaminant characterization in wetland media surrounding a pulp mill industrial effluent treatment facility

“…The goal of this study was to characterize contaminants in wetlands surrounding the Boat Harbour Treatment Facility to focus remediation efforts and to select appropriate remedial options (Eichinger and Walker 2020). To date, most studied had focused on sediment contaminant concentrations in Boat Harbour itself (i.e.…”