The modern sewage water treatment plants (SWTP) are equipped with a biological treatment process that generates a secondary product - sludge - which contains most of the contaminating elements that have been removed from the water.

Since January 1999, Spanish law has forbidden the dumping of sludge into the sea or rivers; consequently, this requires purifying plant working procedures to be more efficient.

The GUASCOR GROUP has a self-developed technology for the complete treatment of sludge, with two lines of action:

• Use of the energy from the biogas.
• Thermal drying of the sludge.

Energy generation from biogas

GUASCOR uses the biogas produced in the anaerobic digestion of the effluent at the purifying plants, the methane content of which reaches 65% - 75% and with a calorific power of between 5,000 and 6,000 kcal/Nm3 , as fuel on the GUASCOR engine-generator sets, which transform it into electrical energy. Part of this energy is for self-consumption on the plant and the rest is exported to the national grid, with the resulting reduction in operation costs.

Advantages of thermally drying sludge

• It manages to achieve a drastic reduction in the volume of sludge (savings in transportation and distribution).
  
  
• It eliminates pathogens.
  
  
• Valorisation of organic material as fertiliser.
  
  
• Production of energy in an environmentally friendly way.
  
  
• Environmental protection, valorisation and reutilisation of a residue.