In just a short 13 months since signing a cooperation agreement for the delivery of Nereda® technology, the EPS/Royal Haskoning DHV partnership is demonstrating success in Ireland. Jim Palmer, Technical Director EPS commented; ‘We have seen an excellent start to our partnership with Royal Haskoning DHV and with three projects currently live (one completed and two under construction) our design and delivery team has rapidly developed the in-house skills and competencies to successfully deliver Nereda® for our customers’.
Aerial view of Clonakilty WWTP in may 2015 prior to taking live flows. Note: the front carousel type treatment streams were only designed for a quarter of the design capacity of the Nereda® tanks and Nereda® will produce effluent to a far higher standard than the original plant.
EPS recently took flow to the new wastewater treatment plant at Clonakilty (20,500PE - Population Equivalent). The wastewater treatment plant in Clonakilty is the first plant constructed in Ireland and the UK using Nereda® technology and the first in the world that is built mostly underground to minimise the visual impact. This state of the art technology is set to displace the century-old activated sludge process that forms the basis for most modern wastewater treatment plants.
Nereda® is an innovative, sustainable and cost-effective biological wastewater treatment technology that purifies water using the unique features of aerobic granular biomass. The success of Nereda® is its high water treatment capability in combination with significantly lower investment and operational costs, a very small physical footprint and high energy savings. Nereda® treats wastewater with aerobic granular biomass: purifying bacteria that create compact granules with superb settling properties.
The technology was discovered by the Delft University of Technology in the Netherlands, and developed in a unique public private-partnership between the University, the Dutch Foundation for Applied Water Research (STOWA), the Dutch Water Boards and Royal Haskoning DHV. After 20 years of research and development this innovative biological solution is now proving itself to be a leap forward in wastewater treatment technology.
What makes the Nereda® process so special is the aerobic granules (biomass). In the usual treatment process, flocs of sludge are suspended in the water. It takes time for these flocs to settle in the treated wastewater. A special secondary settling tank or clarifier is needed. Nereda® granules settle much faster, and can do so in the same tank in which the treatment process takes place.
Nereda aerobic granules (left) compared against traditional activated sludge (right)
Owing to their composition, the granules have an aerobic outer shell which is rich in oxygen and an anoxic/anaerobic core that is low in oxygen. This means that we can find different treatment conditions in a single granule. In a normal treatment plant, the high-oxygen and low-oxygen processes take place in different parts of the overall process.
The robustness and stability of the treatment process under strong varying influent load conditions and extreme influent pH fluctuations is remarkable. Furthermore, even during wintry conditions, extensive nitrogen removal could be established at very high biological sludge loads.
The success of this project was well received in the media following a recent site tour by members of the local community with Irish Water and Cork County Council in attendance amongst others. The introduction of this technology into the Irish market marks a significant milestone and confirms Ireland’s position as one of the leading embracers of modern wastewater technologies. Nereda® will help make EPS and the entire Irish and UK wastewater sector have a more sustainable future.
Community site tour of Clonakilty WWTP, June 2015
Presently, EPS is in the construction phase of a new Wastewater Treatment Plant in Carrigtohill, Co. Cork (30,000PE) based upon the Nereda® process with the plant due to take flows in December 2015. Also using the Nereda® technology, EPS/Sisk JV have commenced construction of the Lower Harbour wastewater treatment plant in Cork (65,000PE). The expected flows to Lower Harbour will take place in Q4 of 2016 and project completion by Q2 of 2017.