The Project:As part of its 5 year Asset Management Program (AMP), Yorkshire Water has embarked upon a £2million upgrade to its Danesmoor Waste Water Treatment Works which serves over 6000 customers. Danesmoor was commissioned in the 1970’s, upgraded in the late 1990’s and now needs a further upgrade to meet the latest regulations on water quality which come into force in 2014. The work to improve the effluent discharge will involve providing two new settlement tanks, and a new tertiary treatment plant. Starting in July 2013, it is expected to take about 15 months to complete the project. Contractor Byzac Entec commissioned WPL to provide the new tertiary treatment plant after a formal tendering process against the Yorkshire Water asset standard and taking into account whole life costs.
The Solution: WPL’s new N-SAF unit was specified to treat ammonia from the waste water, converting it to a permissible level of nitrates which can be legally discharged into the River Rother to bring it in line with the forthcoming tightening standards set by the latest European legislation (the Freshwater Fish Directive).
The Challenges:The size of the proposed SAF units required presented a new challenge to WPL’s designers. The unit has to handle 50 l/sec FFT, almost twice the average, so something out of the ordinary was devised. At 11.7m, 4.6 m tall and 2.9m wide, it is the largest SAF that WPL has ever supplied. Too large to transport in one piece to the site, the design was adapted to allow for the N-SAF to be manufactured and delivered in several parts. Even when the unit was broken down into several parts, the logistics had to be carefully thought out to ensure safe supply, delivery and installation.
The Result:The design has been accepted and the unit will be manufactured and delivered at the end of 2013. WPL will be providing the necessary training for Yorkshire Water staff, and the N-SAF will be up and running on schedule in early 2014. Changes to the treatment process will improve the discharge from Danesmoor Waste Water Treatment Works (WWTW) which means better water quality in the River Rother to meet all the latest legislation.