Reverse Osmosis is a water purification technique performed to remove the dissolved solids from the tannery wastewater thereby reducing the water scarcity. This process produces two types of water namely pure water and RO reject water. The former can be applied for useful purposes in the same industry while the latter did not find any useful application as it contains a high amount of salt content like TDS. TSS, chlorides, sulphates etc. This reject water is conventionally evaporated by solar evaporation pond almost in all the industries of Tamil Nadu. This method has many demerits like large area requirement, water seepage, and dispersal, inefficient during the rainy season, odor, labor requirement, and maintenance. In order to overcome these issues, the solar tunnel dryer has been designed, constructed and observed for its performance.