An experimental study has been made to augment evaporation of tannery effluent (soak liquor) and compare the performance of the conventional fibre reinforced plastic (FRP) flat plate collector with an open FRP flat plate collector. As the tannery effluent flows over FRP flat plate collectors in the form of thin film, the effluent is heated by gaining heat from the absorber due to exposure to solar radiation. Hence, the partial pressure at the interface of the effluent increases, resulting to increase in pressure difference between the interface and air. Thus, leading to increase in mass transfer rate. In this paper, performance comparison is made between the FRP open flat plate collector and the conventional FRP flat plate collector, to understand the effect of climatic conditions, concentration and mass flow rate of the effluent. This study shows that the conventional FRP flat plate collector gives better performance than the open FRP flat plate collector.