A contour plot approach that uses data accumulated during routine monitoring to obtain insights into lagoon behaviour

Regular monitoring of wastewater characteristics is undertaken on most wast ewater treatment plants. The data acquired during this process are usually filed and forgotten. However, systematic analysis of these data can provide useful insights into plant behaviour. Conventional graphical techniques ar e inadequate to give a good overall picture of how wastewater characteristi cs vary, with time and along the lagoon system. An approach based on the us e of contour plots was devised that largely overcomes this problem. Superim position of contour plots for different parameters can be used to gain a qu alitative understanding of the nature and strength of relationships between the parameters. This is illustrated in an analysis of monitoring data for lagoon 115 East at the Western Treatment Plant, near Melbourne, Australia. In this illustrative analysis, relationships between ammonia removal rates and parameters such as chlorophyll a level and temperature are explored usi ng a contour plot superimposition approach. It is concluded that this appro ach can help improve our understanding, not only of lagoon systems, but of other wastewater treatment systems as well.