In general, most of sludge have been disposed of in landfill site or dumped in the ocean. However, the ocean dumping will be totally banned by content of its heavy metal according to London Dumping Convention from 2012 in Korea. Also, the landfill management has a problem which is the shortage of the cover materials because of the seasonal heavy monsoon rainfall and a scarcity of appropriate sites for a landfill. Therefore, the friendly environmental methods are urgently required for the treatment and disposal of the sewage sludge. The thermal hydrolysis is one of the proper treatment methods to solve the sludge problems. This study conducted geotechnical tests in accordance with Korean Industrial Standards(KS) and environmental test in accordance with the Standard Method for the Examination of Solid Waste in Korea to evaluate the feasibility of by-products as the cover materials in landfill. As a result of the tests, by-products are considered to have the feasible characteristics as the cover materials in landfill.