Anaerobic systems: a step forward towards sustainability in purification

Anaerobic purification systems are considered one of the most sustainable alternatives for wastewater treatment. Low energy consumption, low sludge production, small implantation surface, low consumption of chemical products and reduction of operating costs are some of the advantages that anaerobic processes have over conventional aerobic treatments based on activated sludge. In aerobic treatment, a community of microorganisms are used in the presence of air for the oxidation of organic compounds in carbon dioxide and water. The energy required in this process is 0.7 – 1 kWh / kg COD and the volumetric load used is 0.5 – 2.0 kg COD / m3 · d. In aerobic treatment, a community of microorganisms are used in the presence of air for the oxidation of organic compounds in carbon dioxide and water. The energy required in this process is 0.7 – 1 kWh / kg COD and the volumetric load used is 0.5 – 2.0 kg COD / m3 · d. It is important to highlight that the volumetric loads used in anaerobic systems can reach up to 25 kg COD / m3 · d, which allows the treatment of biodegradable wastewater with a high COD content, as well as reducing the space requirements for its implantation. Finally, anaerobic processes also have the advantage of being able to value the granular biomass produced in the market, as sowing in reactors for the start-up of other plants, thus significantly reducing the cost associated with sludge treatment.     Synergistic binomial of biological processes: anaerobic + aerobic Although anaerobic systems may be capable of treating wastewater with higher organic loads than aerobic ones, they have a limited capacity both for the removal of nutrients (ie, nitrogen and phosphorus) and for the refining of organic matter in the effluent (ie, COD removal yields <90%). It is therefore evident that an effective and efficient treatment of industrial wastewater with a high biodegradable organic load with discharge into the hydraulic public domain should be carried out through the synergistic combination of the two biological purification processes:

  • anaerobic, as a roughing treatment and recovery of organic matter in an energy source such as biogas
  • aerobic, as a process for refining the COD and removing the nutrients to comply with the limits established in the discharge authorization.
A case of success in the brewing sector for the treatment of wastewater using mixed anaerobic + aerobic technology is that of the Spanish brewery based in Zaragoza, La Zaragozana (Ambar). The WWTP of the aforementioned beverage company, built and operated by AEMA, is capable of purifying 3,270 m3 of wastewater daily, producing about 5,000 m3 of biogas. The biogas is energetically valued in the facility itself, taking advantage of its calorific power, which contributes positively to the reduction of the brewery’s carbon footprint.       LIFE Multi-AD technology solution The LIFE Multi-AD project is developing and industrializing an innovative technological solution based on the design of a high performance multi-stage anaerobic reactor patented by AEMA. The European R & D & I initiative will help as a technological lever to advance the synergistic combination of anaerobic and aerobic purification systems. The LIFE Multi-AD projet, through the treatment and recovery of wastewater, will reduce the environmental impact of food SMEs as well as the operating costs derived from treatment. The technological solution will enhance the organic load of the wastewater by producing biogas, which will be used as a source of renewable energy, thus saving natural resources and reducing the carbon footprint. The LIFE Multi-AD projet is supported 60% by the LIFE + ENVIRONMENT program of the European Commission and is coordinated by AEMA, as an expert in industrial wastewater treatment technologies. Also involved in the consortium ITAINNOVA, technological center of reference in technological innovation, SIS, company that provides solutions in the field of industrial automation, EGA, specialist in the management and recovery of organic waste through anaerobic digestion and I&S, consultant and advisor in communication of European and international projects.

In aerobic treatment, a community of microorganisms are used in the presence of air to oxidize organic compounds to carbon dioxide and water. The energy required in this process is 0.7 – 1 kWh / kg COD and the volumetric load used is 0.5 – 2.0 kg COD / m3 · d.

It is important to emphasize that the volumetric loads used in anaerobic systems can reach up to 25 kg COD / m3 · d, which allows the treatment of biodegradable wastewater with a high COD content, as well as the reduction of space requirements for its implementation.

Finally, anaerobic processes also have the advantage that they can evaluate the granular biomass produced on the market, as sowing in reactors for the commissioning of other plants, thus significantly reducing the costs associated with sludge treatment.

The synergistic binomial of biological processes: anaerobic + aerobic

Although anaerobic systems may be able to treat wastewater with higher organic loads than aerobic ones, they have a limited capacity for both nutrient removal (nitrogen and phosphorus) and for refining organic matter from effluent (ie removal of COD yields

It is therefore clear that efficient and effective treatment of industrial wastewater with a high biodegradable organic load with discharge into the public hydraulic field should be achieved through the synergistic combination of the two biological purification processes:

• anaerobic, as a treatment for roughing and recovery of organic matter in an energy source, such as biogas

• aerobic, as a process of refining the COD and removing nutrients in order to comply with the limits set in the discharge authorization.

A successful case in the brewing sector for wastewater treatment using mixed anaerobic + aerobic technology is that of the Spanish brewery in Zaragoza, La Zaragozana (Ambar). The treatment plant of the above-mentioned beverage company, built and operated by EEA, is capable of purifying 3,270 m3 of wastewater daily, producing approximately 5,000 m3 of biogas. Biogas is harnessed energetically in the plant itself, taking advantage of its calorific value, which contributes positively to reducing the carbon footprint of the brewery.

LIFE Multi-AD technological solution

The LIFE Multi-AD project develops and industrializes an innovative technological solution based on the design of a high-performance multi-stage anaerobic reactor based on an AEMA patent. The European Research, Development and Innovation Initiative will help as a technological launch pad to advance the synergistic combination of anaerobic and aerobic purification systems.

The LIFE Multi-AD project, by treating and recovering wastewater, will reduce the environmental impact of SMEs in the food sector, as well as the operating costs of treatment. The technological solution will increase the organic load of wastewater by producing biogas, which will be used as a renewable energy source, thus saving natural resources and reducing the carbon footprint.

The LIFE Multi-AD project is 60% supported by the European Commission’s LIFE + ENVIRONMENT program and is coordinated by the EEA, as an expert in industrial wastewater treatment technologies. Also involved in the consortium is ITAINNOVA, a technological reference center in technological innovation, SIS SA, a company that offers solutions in the field of industrial automation, EGA, specialist in management and recovery of organic waste by anaerobic digestion and I&S, consultant and communications consultant. European and international projects.