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Innovation in water technology


In order to offer the best water treatment solutions to our clients, as well as keeping PESA Medioambiente at the forefront of new water technologies, our R+D+i department develops research projects with the most prestigious centres in this field.

The results obtained by our specialists are integrated into our designs, projects, products and services, creating value for our customers either through the optimization of processes, the reduction of operation and maintenance costs, or the achievement of more environmentally friendly solutions.



PESA Medioambiente has developed in the field of R+D+i in collaboration with prestigious research centres, lines of innovation such as: Elimination of nitrogen via nitrite in plants with aerated biological filters (BAF), optimisation of anaerobic digestion by combining mesophilic and thermophilic stages known as Thermo Phased Anaerobic Digestion (TPAD) and pre- treatment of the sludge prior to digestion, as is the case with Sonication, achieving yields in all of them that improve both investment and operating costs with respect to traditional systems, presenting a better fit in the concept of circular economy.

Sonication of sludge as pre-treatment to anaerobic digestion

Technology consisting of the application of ultrasound to a percentage between 40% and 60% of biological sludge before mixing with primary sludge and joint feeding to anaerobic digestion. Advantages:

  • Increase in the rate of organic degradation (volatile solids eliminated) from 45% to 55%.
  • 20% increase in specific methane production
  • Reduction of the amount of sludge obtained by about 15%.
  • Reduction of the amount of polymer used in dewatering by up to 20%.
  • Optimisation of digestion performance

 Diptych Ultrasonic pre-treatment

Biological Aerated Filter - Biofilter (BAF)

Biological treatment technology for both municipal and industrial wastewater that allows the elimination of suspended solids, organic matter (BOD) and nitrogen (Nt) and in which the biomass is fixed in a medium that in turn acts as a filter. Advantages:

  • Reduction of the space required for the treatment of the same flow rate
  • Better effluent quality than activated sludge treatment
  • High adaptability of the system to changes in flow rates and loads
  • Elimination of sludge decanting systems
  • Automatic filtration of suspended solids as fluid passes through the filter
  • The combination of this process with the application of a Nitrogen removal system via Nitrite, also provides the advantages mentioned for a process of NDN via Nitrite (see below).

 BAF diptych

Nitrogen Removal via Nitrite

Technology applied in the elimination of nutrients, specifically nitrogen, from municipal or industrial wastewater aimed at controlling the process of Nitrification – Desnitrification in such a way as to allow the oxidation of ammoniacal nitrogen up to nitrite, avoiding its subsequent oxidation up to nitrate, and allowing the transformation or direct passage of this nitrite to nitrogen gas. Advantages:

  • 25% reduction in electricity consumption with respect to the conventional NDN process
  • 40% reduction in the organic load required to remove nitrogen compared to a conventional NDN
  • The combination of this process with the application of the same in a BAF, also brings the advantages mentioned for the use of BAF
Temperature Phased Anaerobic Digestion (TPAD)

Combination of mesophilic and thermophilic anaerobic digestion processes in series to obtain the advantages of both systems together. Advantages:

  • Increase in the volumetric production of CH4 (m3/m3R*d) according to the configuration of up to 70% compared to a mesophilic DA in a single step.
  • Increase of the specific production of CH4 (m3/TnSV) according to the configuration of up to 50% with respect to a mesophilic DA in a single step.
  • Less hydraulic retention time required, which means less digestion volume required for the same flow or, for an existing DA volume, more treatment capacity.
  • Up to 25% more efficient removal of COD and SV than mesophilic DA in a single step.
  • Elimination of up to 55% of SV
  • Lower investment and operating costs than other processes such as Thermohydrolysis (TH)
  • Reduction of the costs for sludge management due to the reduction of the amount of sludge.


 Díptico TPAD

Temperature Phased Anaerobic Digestion (TPAD) con recirculación de biomasa
  • It allows to increase the efficiency of the process in existing plants where there is no room to build new digesters but where it is necessary to increase the flow.
  • Better resistance to periods when there are overloads and inhibition phenomena.
  • Reduction of the inhibiting effects by accumulation of volatile fatty acids with respect to a mesophilic DA.
  • Increase in the specific production of biogas with respect to a conventional DA.
  • Improved digestion process in terms of CH4 production and organic matter removal.
  • Reduction of the costs for sludge management due to the reduction of the amount of sludge.

 Diptych TPAD recirculation

Solar sludge drying with or without residual energy input

Technology for the drying of dehydrated sludge with an initial dry matter content of 18 – 20% to a final dryness of 90% with the contribution only of solar energy or this plus residual energy of some industrial process in the plant, by means of its use for the heating of a water circuit as radiant floor located in the floor of the greenhouse. Advantages:

  • Low temperature process, which avoids the generation of explosive atmosphere on the dry sludge side with respect to technologies that require dry sludge recirculations at the dryer inlet and work at high temperatures.
  • Continuous operation from the feeding of the sludge to its collection as a dry product.
  • Valorisation of dry sludge as fuel. 3Tn of dry sludge at 90% MS is energy equivalent to 1Tn of coal.
  • Continuous movement of the sludge in the dryer, avoiding agglomerates that can cause the development of fermentation processes, and consequently, avoid bad odors.
  • Granulometry final product between 0 and 10 mm.
  • Absence of dust.
  • No contact with the product.
  • Low maintenance level.
  • Electrical consumption less than 25 kwh/Tn evaporated water.
  • Possibility of using residual thermal energy from other processes and reducing the required drying surface by up to 75%.
Sludge drying with or without residual energy at low temperature

Drying technology by means of belts in which the sludge is deposited, through which a flow of air flows in a closed circuit. The air, heated in an air/water exchanger thanks to the thermal contribution provided by the boiler burning of the biogas obtained from the anaerobic digestion of the WWTP, passes through the tapes with the humid ´lodo, the water evaporating and being dragged with the air flow. This will be cooled later, condensing the water it carries and being evacuated. The air, it starts the process again. Due to the presence of incondensables, the air pressure increases, which is why a small flow of air that has to be deodorized is purged in a continuous way.

Although the energy consumption is higher, equivalent to about 120 kwh/Tn evaporated water, the required surface area is much lower, so the initial investment values may be equivalent to the previous case, so the availability of space can be an important element when choosing the solution.