HALIFAX — Northern Pulp says it has started giving layoff notices to management employees at its Nova Scotia mill. The company has moved to mothball the mill after its plan for a new treatment system that would see it pump treated effluent into the Northumberland Strait was rejected by the province. …The announcement came as the firm announced Thursday it will go to court to seek a judicial review of the province’s requirement it file an environmental assessment. The company says in a release it wants to bring the matter before the court so it can get “clarity about the process and elements required in order to be successful in the environment assessment process we’ll be embarking upon later this year.”