Portable SAFs ensure environmental protection during upgrade

Technology from water recycling specialist WCS Environmental Engineering (WCSEE) has been selected to maintain ammonia consent standards during an upgrade of a village treatment works.

British water supply company Severn Trent Water is upgrading the wastewater recycling plant serving Albrighton in Shropshire, UK. Planned for the end of 2022, the project will be undertaken by the utility’s contracting partner, construction company Galliford Try.

WCSEE will provide two T1000 hybrid-submerged aerated filter (SAF) treatment units, to deliver ammonia removal at the plant while existing treatment processes are offline during the construction phase.

WCSEE Hybrid-SAF technology

The SAF units will be able to treat a peak flow of 25l/s, while maintaining compliance with environmental permit requirements of 4mg/l ammonia. The environment agency’s regulations state the site must meet these standards at least 95% of the time.  

Modular in design, with a 30% smaller footprint than comparable technologies, the SAF units will be built off-site and are expected to be in operation at Albrighton for about a year. They will then be retained by Severn Trent as portable and flexible assets to be used on other sites when required.

WCSEE utilities manager Andrew Haywood said, “During a treatment plant upgrade, it is critical that stringent ammonia removal continues to be delivered while parts of the site are taken offline. This is a priority for utilities. Environmental compliance must be maintained throughout construction, to protect local watercourses and avoid regulatory penalties.

“The hybrid-SAF tanks that Severn Trent is purchasing will deliver treatment, ensuring compliance is maintained while the work is underway. The modular nature of the units means that on project completion, they can be easily removed, stored and transported to other sites when needed.”

He continued, “Having this flexibility is a major benefit for utilities; the technology can be quickly installed and commissioned, giving peace of mind that sites can remain operational and within environmental consent during planned or reactive work.

“We have worked closely with our client Severn Trent for 10 years, and we are pleased to be supporting both their in-house team and their partner Galliford Try with this important project.”

WCSEE engineer with Hybrid-SAF technology

Severn Trent service delivery manager Andy Bradford said: “WCSEE’s hybrid-SAF technology will be key to keeping our Albrington works fully operational. Compliant while construction, led by Galliford Try, is underway. Purchasing the units means they will be added to our asset base to be installed as required across our sites, ensuring environmental compliance at all times.”

The hybrid-SAF treatment technology employs a submerged moving-bed, fixed-film reactor, which can treat wastewater with greater energy efficiency compared to traditional submerged SAFs, and in a tighter site footprint.

In spring 2022 WCSEE introduced energy-saving timers to operate the blowers that provide oxygen for the biological treatment process. The blowers are now timed to pulse air into the process rather than operate continuously, reducing the energy consumption of SAF units by up to 50%.