The sewage can be effectively purified by passing it through a purification plant comprising a septic tank and a filter bed. The solids present in the sewage settle out in the septic tank and are reduced by a process of anaerobic digestion; the settled sewage from the septic tank is then sprinkled evenly over the filter bed and final aerobic purification takes place as the liquid flows through the media. Wherever possible, the liquid flowing from the filter bed should be irrigated over land, but if the effluent is to be discharged to a water course, a small humus settling tank is required after the filter bed to remove the fines solids produced during aerobic purification process in the filter bed.

Small plants of this type operate efficiently with very little attention. The septic tank requires de-sludging two or three times a year, but where incorporated, the humus tank requires de-sludging at more frequent intervals, and it is for this reason that irrigation of effluent is preferable when possible.

For the production of satisfactory effluent, however it is essential that the settled sewage should be distributed evenly and regularly over the filter bed; the Simplette Revolving Sprinkler will perform this function reliably in all weathers with the minimum of attention.

A minimum natural fall of 6ft is necessary to allow the sewage to flow by gravity through to the purification plant; where this fall is not available, pumping equipment has to be incorporated into the installation.

The simplest and most economical arrangement is to pump the settled sewage from the septic tank to the filter bed situated at a higher level.

The Pneu Pump, an extremely simple, air operated pump, is especially suitable for this duty.

Simplette Spinklers

The sprinkler, which is carried on supporting bars, comprises a waterwheel box, a hollow main beam spanning the filter bed, and a rotating distribution trough of open channel section.

The Simplette Sprinkler is a simple and robust machine designed for long, trouble free service. All mechanical parts are of ample strength, and particular care has been taken throughout the design to avoid trouble spots where corrosion or blockage might occur.

The PNEU Pump

The PNEU Pump is operated by a small supply of air from an electrically driven compressor. The pump body is arranged in a sump which receives the settled sewage flowing from the septic tank and a simple float switch is provided to control the compressor unit automatically and bring the PNEU Pump into operation.