Drinking water treatment and reuse

Drinking water

Drinking water for human and industrial consumption is an increasingly sought after asset, with its demand rising in line with modern society's demographic and industrial growth.

The ever more demanding health regulations, together with the increasingly destruction of natural resources (rivers, lakes, wells, sea,etc.), requires specialized companies familiarized with the maximum possible number of processes and technologies to be used, so as to be able to offer consumers the highest guarantees for their water consumption.

We use processes from the simplest to the most sophisticated ones, designed to fit the problem.

Water treatment plants for human consumption built by aqualia infraestructuras and aqualia currently supply over 10 million people. We have nearly thirty references, some just finished and others ongoing of old plants. Amongst these we may highlight references such as the one in Lingzhuang, (750.000 m3/day), and  Jiexuan (690.000 m3/day) in China, or  El Atazar (691.000 m3/day) in Madrid.

From the past to present we have used practically all known processes.

For physical and chemical treatments we use simple gravity settlement tanks or on different levels, lamellar ones, with sludge recirculation, sludge blanket, in filtration we have references with several types of open or closed filters and in disinfecting, we have worked with different compounds in chlorine or ultraviolet rays. Over the years, we have developed our own technology for each process, incorporating the details and improvements in knowhow gained on site at the plants we have executed. In the last few years, we have been developing sludge treatment lines in some drinking water plants so as to allow sludge to be sent directly for landfill.

Reuse

Though treated water has been reused directly by mankind for years, the new national and regional regulations now oblige us to control some parameters that might cause harmful side effects. In the last few years, either through public or private enterprise and especially in areas where the shortage or bad quality of the water has become a social problem, we have executed plants for treating water from secondary biological treatments, with the aim of enchancing the physical and above all the sanitary characteristics.

They are plants known as "tertiary treatment plants", and that are used for irrigation in parks, garden or golf courses, road cleaning, refilling aquifers or for replenishing ecological flows in polluted rivers.

To achieve all this, we have used physical processes for settlement by gravity or flotation, (with the help of reagents when necessary), conventional filtration through beds of sand and anthracite, ring filters, combined disinfecting with ultraviolet rays and chlorine, etc. In places where we have found unacceptable salt contents that might seriously damage land disposal, we have performed tertiary treatments with the use of membranes.

We have some pioneering references for the domestic market, such the tertiary treatments at the Sant Feliu WWTP (with open filters and disinfectant), WWTP of Vilaseca- Salou WWTP (lamellar settlement tanks, closed filters with two layers and disinfecting), WWTP for La China (lamellar settlement tanks, open filters and disinfecting with ultraviolet rays), WWTP in Alcobendas (flotation, ring filters and disinfecting with ultraviolet rays and chlorination), as well as the programme for the reuse of water at three plants on Lanzarote in the Canary Islands, where the main problem is the salt that is removed through reverse osmosis, prior treatment with continuous micro filtration in hollow fibre membranes, to produce water of a very high quality for irrigation.