Nutrient removal in a vertical upflow wetland in Piracicaba, Brazil

Vertical upflow wetland systems have shown high nutrient removal efficienci es. The removal of nutrients (N and P) from wastewater was investigated in a vertical upflow wetland system in Piracicaba, Brazil. The concentration r emoval was 93% for phosphate, 78% for nitrate and 50% for ammonia. Effectiv e phosphate removal was observed in the top soil layer which has a high sur face adsorption area. Nitrate was removed satisfactory at low loading rates due to plant uptake and denitrification. Removal of ammonia was concentrat ion dependent and decreased at high inflow concentrations. Spatial sampling through the bed showed that the treatment efficiency was not uniform. The possibility of the recycling of nutrients as a soil improver or animal feed is an important feature of this type of vertical flow wetland system.