ALKALINE STABILISATION OF RESIDUAL SLUDGE IN CLOSED SYSTEMS WITH OPTIONAL AMMONIA RECYCLING

The invention relates to a method for the alkaline stabilisation of residual sludge in closed systems with optional ammonia recycling, which produces biosolids having concentrations of pathogenic micro-organisms which comply with Mexican and international regulations and which have characteristics making them suitable for use in agricultural soils, for improving soils, for remediating contaminated soils, for generating soils in infertile areas and as an intermediate cover for sanitary landfills and embankments, without causing health or environmental problems. The aforementioned process can be optimised with the use of ammonia as a sub-product which can be recovered and recycled to the system in order to utilise the high disinfecting power thereof and to market same owing to the different industrial uses thereof. The ammonia recycling process increases the nutrient content, thereby ensuring that the sludge obtained is suitable for agricultural activities. In addition, the mass of the sludge is reduced since less alkaline material is required, thereby reducing both the operating costs and the biosolid transport costs.