Introduction.

Biological anaerobic wastewater treatment generates by-products such as sludge, a non-hazardous waste that requires treatment for its disposal.

Objective.

In this work, the effect of the application of hydrogen peroxide (H2O2) and alkaline stabilization with lime (CaO) on the reduction of sulfur and the viability of helminth eggs were respectively evaluated. The test was applied to the sludge from the biological anaerobic wastewater treatment plant of a chocolate factory.

Materials and methods.

A general description of the process and of the sludge generated in this particular wastewater treatment is given. Parameters such as pH, redox potential (Eh), average density, sedimentation rate, sulphide concentration and the viability of helminth eggs were determined. The treatment was performed by simulating the sludge dehydration process that takes place in the plant. The different amounts of CaO and H2O2 were supplied in accordance with the experimental design performed in Statgraphics.

Results.

Before applying the treatment, acid pH and negative redox potential values were found, obtained both along the Imhoff and at different depths. The sedimentation rate found corresponded to a disperse sludge. After the application of each treatment in the sludge, pH results were alkaline, the redox potential showed positive values at several points, and there was presence of viable helminth eggs before and after the procedure.

Conclusion.

The reduction of sulfur concentration had an efficiency of 98.56%, yielding a non-reactive mud as a final product.