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One of the main quality problems of biosolids from domestic wastewater treatment plants -WWTP- is the high concentration of pathogens, often classified as a class B, with restriction for use in agriculture. This study evaluated the alkali stabilization of biosolids from Cañaveralejo wastewater treatment plant (PTAR-C), located in Cali, Colombia, in order to improve their microbiological quality using two types of lime (quick and hydrated) with doses between 8 to 25 % and two types of ash with 8 to 40 % as doses, in experimental units 0,2 m2 with 13 days of contact time. The results showed that both type of lime reached the total reduction of evaluated monitoring variables (faecal coliforms, Salmonella sp, helmints eggs) while the alkali power of ashes were lower. The obtained biosolids treated with lime have a high potential use in agriculture purposes for the good microbiological quality, and for the organic matter and nutrient content (N, P) that can generate benefit to the soil, but it is recommendable to evaluate at pilot scale the lime doses and application of biosolid in different soils types and crops in order to precise the benefits or prevent measurements before application of material in soil. [ABSTRACT FROM AUTHOR]