The detection of floating oil on rivers and final effluent streams is very important. Sites abstracting river water for potable water production and industry discharging to local water courses often monitor for floating oil.

Some applications require oil to be expressed as a concentration. This is often a difficult measurement and would be performed using a flow-through technique. Obtaining a representative sample and maintaining the instrument’s sample pipe work & flow-cell from oil coatings, in addition to possible measurement interference, can affect reliability. PPM have therefore only offered such instrumentation for applications where concentrations are very low and suspended solids are not typically present. (Boiler water and condensate return).