Water Treatment

Wastewater treatment aims to eliminate undesirable, polluting, harmful, or toxic components from the water, depending on the potential risks to human health or the ecosystem that will receive the treated water. This technique is carried out in a Wastewater Treatment Plant (WWTP).

We design our wastewater treatment plants with the objective of fulfilling their mission with a minimum cost of the integral Life Cycle of the facilities as well as a commitment to the environment. With more than 125 wastewater treatment plants, we treat the wastewater discharges of more than 29 million inhabitants.

How is wastewater treatment carried out in the WWTPs?

The treatment process is divided into two main phases. It usually has an inlet (collector) and an outlet (effluent). A flow of water from domestic, industrial, or agricultural activity passes through the inlet, and through the outlet, the water is returned to the network or to the environment in its optimum state and according to the quality required by the regulations. Sometimes the water is reused.

What kind of treatments are done in a WWTP?

Primary wastewater treatment

When entering the WWTP, wastewater passes through pretreatment and primary treatment. It is common for water purification and desalination. The purpose of pretreatment is to protect the installations from coarse debris. The primary treatment removes the rest of floating solids, suspended solids, sands, fats, and oils.

As an example, the Utebo treatment plant has an inlet, screening of fine solids, sand trap, and degreaser and a flow regulation measure. It also has a storm tank designed to receive the surplus during pretreatment. This is also the case of the Ahigal, La Granja, Mohedas de Granadilla and Zarza de Granadilla (Cáceres) stations.

Secondary wastewater treatment

After physical treatment, the water passes to secondary treatment, usually chemical or biological. The main objective is to eliminate the organic matter that remains trapped in sludge composed of heavy metals, pathogenic bacteria, phosphorus, nitrogen, or carbohydrates, among others. The most common treatments are sequential reactors, facultative and aerated lagooning, peat beds or biodiscs.

When the plant is large, as in the case of Valle de Güímar (Tenerife), part of the secondary treatment is called tertiary. The objective of this is to reduce suspended solids, coliforms, and other pathogenic elements.