Introduction.

As a result of the purification of wastewater through biological processes, biological sludge emerges as one of the most important waste in the WWTP, for which in Colombia an average production of274 tons per day is calculated.

Objective.

To evaluate the process of stabilization of sludge from an anaerobic wastewater treatment plant, by means of Biodigester Bales.

Materials and methods.

After the construction of 4 bales with different concentrations of biological sludge, monitoring of temperature and pH was carried out for four months. They were then taken to the laboratory of the GIEM group to carry out the physicochemical and microbiological studies.

Results

It was observed that in no case the temperature exceeds 50 ° C, pH was 7.5 and U of pH was 3.5, and the bales remained saturated with moisture. Appropriate values for CEC, TOC, and C/N ratio are reported. Acceptable values are reported for TON and P as well as compliance with requirements for heavy metals except for the nickel concentration. There is presence of both total and fecal colifor-ms and helminth eggs.

Conclusion.

From this investigation it is finally concluded that the stabilization process achieves better results as the concentration of kitchen waste increases and that although a product with appropriate characteristics is achieved to be supplied to the soil either as organic fertilizer or for amendment of soils, a longer time is required to achieve total maturation of the resulting bevel and the inhibition of indicator microorganisms such as helminth eggs.