Eichhornia crassipes-based tertiary treatment of Kraft pulp mill effluentsin Chilean Central Region

This paper presents experimental results on the implementation of Eichhorni a crassipes-based tertiary lagoon to treat effluents generated by a 300 ton d(-1) Kraft pulp mill in Chile. Results show that E. crassipes rapidly ada pted to the tertiary lagoon conditions. Active growth was maintained even d uring a cold winter, protected by the wastewater heat content. A 1000 m(2) seeding area extended to 2300-6200 m(2) after a month of growth, with a mon thly harvested biomass and nitrogen uptake were 1.1-5.4 ton (dry wt.), and 18-127 kg N, respectively. E. crassipes growth was adequately described by a first order model, with an estimated rate constant ca. 0.03 d(-1) and 0.0 6 d(-1), for winter and summer seasons, respectively. A management strategy based on such model, to account for seasonal variations in growth rate whi le keeping a constant nitrogen uptake capacity, is proposed here.