Articles & Case Studies


Posted: Friday 19th December 2014

Ashford Wastewater Treatment Works has undergone a £12.6 million redevelopment as part of Southern Water’s future investments. Serving a population equivalent of 100,000, the demand is set to increase to 130,000 by 2020 therefore the expansion undertaken by the contractors Barhale was critical.

To ensure the high standard of service was maintained and able to accommodate a 30% increase in flows and loads, Southern Water specified the best suppliers to meet their high expectations through design workshops in which Hewitech successfully showcased their range of cross flow media. All products had to contribute towards achieving National Environmental Programme (NEP) consent requirements while ensuring that the installation process wouldn’t affect the live water works and Southern Water customers.

Constructing a fourth nitrifying trickler filter (NTF) was essential in increasing the water works processing capacity. The NTF facilitates the nitrification of the wastewater to remove ammonia, a vital process, as it is not only toxic to aquatic life but also places a high oxygen demand on receiving waters as well as promotes algal blooms.

Hewitech’s CF 15 PP Cross flow was specified for the application as NTF media as its structure provided a suitable surface for the growth of the bacterial film necessary in the nitrification process. The polypropylene 190m2/m3 model was applied in 1733m3 quantity, providing a large surface area through which a substantial volume of water can be filtered.

NTFs benefit from many advantages over other systems, low power requirements and durability of process elements as well as the ability to handle and recover from shock loads being some. The cross flow media also benefits from promoting better bio growth and lesser chances of plugging.

After confirming that the Hewitech media conformed to the specifications required as laid out in the Southern Waters Technical Specification Manual for Wastewater Treatment, Hewitech was selected by Barhale on account of its commercial competitiveness.

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