The TETRA® Nitrifying SAF (NSAF), provided by Severn Trent Services is a robust solution, based on established TETRA SAF technology for tertiary ammonia removal. The up-flow, fixed film biological system represents a simple, proven and cost effective way of achieving ammonia standards down to as low as 1 mg/l on a 95 percentile basis.
A biological treatment only step, the TETRA NSAF can be combined with tertiary solids removal processes, either new or existing, or where discharge limits permit will allow direct discharge without further treatment.
The filter design is based on proven TETRA T Blocks and uses blast furnace slag media for operating and cost advantages over other systems. Other medias such as structured plastic can also be utilized to meet specific requirements.
In addition, TETRA NSAF technology utilises a simple process in which air is supplied at a fixed rate, thus eliminating the need for complicated control systems.
The NSAF+ is a recent development to match the plant’s treatment capability to the incoming load and thereby ensure significant reductions in operating costs.