Drouge tracking by image processing for the study of laboratory scale pond hydraulics

Waste stabilisation ponds are one of the most widely used methods of wastewater treatment for small communities throughout the world. The treatment efficiency of waste stabilisation ponds is directly linked to their hydraulic regime, but to date pond hydraulics have been poorly researched. Because of climatic variation these low velocity, long residence time systems are difficult to systemically study in the field. An alternative is to undertake research on scale-model ponds operated under controlled conditions in a laboratory. This paper details a procedure that uses image processing for quantifying the velocity distribution and flow pattern within a scale-model pond using image processing. This technique is outlined in detail and examples of results derived from its application are presented. It is concluded that this technique is both effective as a relativity cheap and fast method of quantifying the flow behaviour in scale-model ponds. Furthermore because it continuously records the flow behaviour over a period of time, it can highlight unsteady-state flow behaviour that could otherwise go undetected when using other flow measurement techniques.