The treatment of tannery wastewater in the Common Effluent Treatment Plants (CETPs), Effluent Treatment Plants (ETPs) and Pre-treatment plants in individual tanneries, generates significant volume of tannery sludge in the present time. The sludge is generated by the primary treatment as chemical sludge and secondary treatment as bio-sludge. Due to the presence of chromium, the chemical sludge produced by the primary treatment must be disposed of in a secure landfill system. As a result, when the sludge is sent to the landfill system, the moisture content must be decreased to the extent possible in a sustainable way for reducing the disposal cost. A lab scale solar dryer has been fabricated and experiments were carried out for the reduction of moisture content. The chemical and bio-sludge from CETP treating the tannery wastewater was collected for the study. Sludge dewatering has been studied and samples were kept inside and outside solar dryer to compare the performances. From the results, it was found that the bio-sludge kept inside solar dryer showed better performance comparing with the chemical sludge. It is also noticed that the bio-sludge having slightly higher drying rate than chemical sludge as the bio-sludge is rich in organic and porous which circulate the generated heat inside the sun dryer over the surface of the sludge particles, reducing their moisture content.