Water pollution by nitrates: Salher solutions to remove them

Aquifers in Spain are increasingly at risk of chemical contamination by excess nitrates in their waters. This news comes just when the European Commission gives an ultimatum to the Spanish Government to act against the nitrate contamination of its waters.

Water quality is one of the most important elements of the European Union environmental policy. Because of this, to avoid penalties, the Government of Spain has three months to review nitrate vulnerable areas, reinforce action measures and correct the detected deficiencies.

Recent cases of eutrophication and the excessive presence of nitrogen compounds (nitrates) in surface and ground waters can cause serious consequences for human health and negative effects on ecosystems. Nitrate pollution in water courses, mainly from diffuse agricultural, farming and industrial sources and, in less quantity, extent from sources of urban origin, implies the necessary treatment and control.

The main source of nitrogen in urban wastewater are the proteins ingested by people in their diet, which reach the water as urea. In sewage networks, urea is rapidly converted to ammonia, and organic nitrogen compounds are hydrolyzed by bacteria and converted to ammonia. Therefore, most of the nitrogen that reaches an urban water treatment plant is in non-oxidized form. All of the non-oxidized nitrogen is what is called Total Kjeldahl Nitrogen (NTK).

When we talk about wastewater of an industrial nature (factories, agricultural and farming sector, etc.), in addition to nitrogen compounds in a short form (NTK), there are also large contributions of nitrogen in oxidized form (nitrites and nitrates).

To improve the health of aquatic ecosystems, Salher provides technologies and equipment designed to remove nitrogen compounds from urban and industrial wastewater, as well as to generate drinking water:

• Urban and Industrial Wastewater: Biological oxidation process and nitrification – denitrification processes, among others.
• Drinking Waters: Ion exchange processes and reverse osmosis, among others.

The removal of these nitrogen compounds (ammonia, organic nitrogen, nitrites, nitrates) in urban and industrial wastewater and drinking water will depend fundamentally on the characteristics of the substrate, the nutrient ratios, the oxygen supply, the water temperature, salinity and the presence of toxic elements or inhibitors.