29 jan 2020

Nereda® technology is delivering excellent results across the world – with installations in six continents and multiple climactic conditions. One of the process’s big advantages is its ability to perform even in extremes of temperature. Whether it’s the heat of South America or Australia, or the freezing temperatures of Sweden or Poland, Nereda technology can be trusted to purify wastewater whatever the weather.

The Nereda wastewater treatment process relies on anaerobic technology to make its science work. The basic concept of the process is that the technology purifies water using the unique features of aerobic granular biomass. The biomass develops within the tanks as fast-settling aerobic granular sludge.

The technology also has a variety of advantages over its competitors. These include having a small footprint, with only 25% area needed for the site, and it is sustainable, with 30-50% energy savings and no chemicals used. The plants are also more cost-effective, with significantly lower CAPEX and OPEX. The process’s versatility in application is also a big advantage. It can be used in greenfield sites, as a retrofit CAS or SBR, or as a hybrid capacity extension.

The highs and lows

Perhaps the most advantageous aspect of the Nereda process is the fact that it operates in extremes of temperature, with no loss of efficiency and performance. There are almost 80 Nereda plants sited around the globe, operating in all kinds of climactic conditions. Many are in temperate zones but further afield there is a great deal of variance in the climate.

Dealing with variations

For example, the municipal Nereda plant in Strömstad, Sweden was a challenging design for two reasons. As Strömstad has a high frequency of tourists, resulting in significant variation in treatment capacity required throughout the year. Additionally, the plant must able to operate at low temperatures during the winter months, without the results being affected. Nereda technology addresses both these challenges and provides a high level of water treatment withstanding these variations.

The same was true of the Nereda plant in Riki, situated in the eastern Polish province of Lublin. In addition to the usual considerations with such an installation – an increased capacity due to population growth and new regulatory requirements – the plant at Ryki needed to be able to deal with very low process temperatures during the winter months. In the end, the works has successfully dealt with considerably lower wastewater temperatures than was initially envisaged.

The anticipated minimum design temperature was 12 °C, but the biological process in the Nereda reactors was initiated in almost freezing conditions, around 4°C. Only three months later, at the end of April, was the actual design temperature (7-8°C) achieved. The highest process temperature of 23°C was reached in summer 2015, demonstrating that the Nereda technology can operate in changeable temperatures, even at a single site.

Dealing with high temperatures and humidity

At the other end of the spectrum, the Nereda treatment plants at Kingaroy, Australia and Araguaína in Brazil deal with high temperatures and humidity. At Kingaroy, a township within the South Burnett region of Queensland, as well as operating at high temperatures, the plant also supplies the Kingaroy community with water via recycled water reclamation. During the summer, up to half of the resulting effluent discharge is reused for watering sporting fields and a golf course in the vicinity. In Brazil, the Nereda site has had to not only deal with large population increases, but also operating in extreme humidity, where a low-odour operation is also a major asset.