Ten wetland ponds, each 1430 m2 (1/3 acre) in area are being utilized to evaluate the treatment of wastewater from a pulp mill. The ponds are being operated at a depth of 46 cm (18″) and detention times are 2 and 10 days. Six of the ponds have been planted to cattails (Typha latifolia) and three to bulrush (Scirpus acutus). One of the ponds is filled with large (150 mm) stone to compare a subsurface non-plant system.
In 24 stock tanks, 8 aquatic plant species (Cattail, Hardstem Bulrush, Bolander's Rush, Common Spike Rush, Water Mannagrass, Beaked Sedge, Water Parsley and Yellow Pond Lily) are being grown to evaluate the effect of plants in the wetland treatment of wastewater. These same species are being evaluated in a larger area for competitiveness and hardiness in the wastewater.
The ponds were planted in the winter of 1990/91. Results of this work on treatment of biochemical oxygen demand, solids and colour removal will be reported. Removals are in the range of 55%, 70% and less than 5% for the three parameters, respectively.