TREATMENT PLANTS.We evaluated the effect of thermal drying (60 to 75 °C and times from 0 to 12.58 h) and alkaline treatment (Ca(OH) 2 and CaO at doses from 8 to 10%.) on the microbiological and chemical characteristics of biosolids from the Cañaveralejo WWTP.The results showed that in thermal drying all temperatures studied were sufficient to achieve the sanitation of biosolids.In the alkaline treatment the two types of lime showed the total elimination of fecal coliforms, E. coli and helminth eggs, however, the process of alkalization of biosolids had significant influences on organic carbon and calcium.