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Submerged Aerated Filters

SAF wastewater treatment systems are designed to meet the specific requirements of a particular project. It is built in accordance with design criteria supplied in the form of a technical specification or as required to meet varying influent and effluent characteristics and flows.

SAF is an efficient and well-proven biological treatment process which is used to biodegrade organic matter. It can also reduce nitrogen in the wastewater to deliver a treated wastewater that exhibits a very high level of BOD, COD and Nitrogen reduction along with high levels of reduction in suspended solids. This treatment process is ideally suited to low to medium treatment volumes requiring either a Class C or Class A effluent quality in a compact containerised supply arrangement.

BOD and COD are used to measure water quality, with BOD used to determine how fast biological organisms use up oxygen in a body of water while COD measures the amount of organic compounds in water.

Depending on the characteristics of the application, the system may require a range of pre-treatment units (coarse & fine screening, grit removal, FOG removal); a purpose engineered SAF biological process; feed, transfer and recirculation pump systems; blowers to provide process aeration; disinfection systems; sludge management systems; and an overall control system.

In any wastewater process, effective screening is required and this screening depends on the downstream process and its ability to cope with particles typically present in the wastewater which will not affect the daily operation of the plant i.e. pump blockages. If required, screening for Tristar SAF systems is typically provided by means of a raked bar screen of 3mm aperture, which deposits the screened material into a skip bin for off-site disposal.

The operational cycle of a SAF system usually does not vary from one application to another. A typical cycle would commence with wastewater being collected in the balance tank at the front end of the plant – thus offering some flow buffering during peak inflow periods. This collected wastewater would then be pumped (at a controlled rate) to the following downstream tanks in an overflow cascading arrangement; thus providing minimal energy requirements.


"It was a pleasure working with you on a challenging project in a very challenging situation. I appreciate all your efforts."

Eric Jenkins, Axon EP 

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