Experimental studies for improved nitrification in shallow lagoon systems

Two separate experimental studies aimed at enhancing nitrification in lagoon systems are described. In the first study a system of four 1:10 scale experimental ponds was used to evaluate the potential for enhancement of nitrification through the control of hydraulic loading rates to lagoon systems. A relationship incorporating the parameters: hydraulic retention time, nitrifier growth rate, temperature, pH and chlorophyll a concentration was established. This relationship provides a useful guide to managing lagoons but further work is required to provide a better understanding of the processes involved. In the second study eight laboratory-scale reactors were used to evaluate the potential for enhancement of nitrification through the use of algal/bacterial biofilms. The study showed that these biofilms have the potential to enhance nitrification, particularly under more adverse conditions such as low hydraulic retention time, high organic loading and low levels of D.O., pH and temperature.