There are many advantages in using a simple Super Siphon based primary treatment system. Some of these include:
A modern primary septic treatment system with the Super Siphon is even cheaper than the old septic tank and field tile system . Early in the development process Colin Ashby designed a standard septic tank system for a client who then went overseas. In the meantime Colin, working with David Kay and a local tank manufacturer designed a two chamber septic tank with dosing siphon. When the client returned he decided to install the new siphon system instead and got the same drainlayer to reprice the new installation. The revised installation including the cost of the siphon worked out to be 15% cheaper. It was found that this was due to smaller and cheaper pipes, trenches, drainage metal quantities and spoil to get rid of.
A modern primary treatment system with the Super Siphon is also significantly less expensive to install than the secondary treatment "package" system for two reasons:
a) Initial capital costs of secondary systems are higher. While the field installation cost of secondary system dripperlines may be a bit cheaper than an LPED field, the treatment units themselves are more complex and hence more expensive than a simple two chamber septic tank with filter and siphon. Typically a Super Siphon system will work out at between 35% to 75% of the installed cost of a secondary system.
b) Ongoing operating costs are higher for secondary systems. All secondary systems require power to operate, maintenance contracts to be entered into with the installer, and regular six or twelve monthly visits by maintenance personal for inspection and cleaning of the pump, filters and alarm systems. The local authority may require a permanent maintenance contract and regular inspections by outside contractors as a condition of installation consent. Primary Super Siphon dosing systems use no power, have no alarm and no pumps to require inspection or break down. The maintenance requirements are minimal and can be done on an as needed basis by a local drainlayer or by the homeowner themselves without any maintenance contract required.
2) Long Life Effluent Fields
With the old septic tank and field tile system the field was dribble fed progressively sliming up the first section with anaerobic effluent then sliming up the next section and so on resulting in the progressive failure of the entire field. The life expectancy for a conventional field tile system is eight years.
With the the dosing siphon system however the entire field is evenly dose loaded a few times a day for two or three minutes and then the system rests for several hours allowing the soil to aerate and aerobic bacterial action to take place. The aerobic action is sweet and non smelly and actually improves the quality of the soil, turning silty clays over time into rich friable topsoil. The field does not clog but actually improves with age and therefore in theory the field has an infinite life.
3) Robust with Low Maintenance Requirements
In a primary dosed system the ongoing maintenance is as follows:
a) The outlet biological filter in the septic tank should be inspected and lightly hosed off once a year. b) The ends of the disposal field lines should be sequentially opened and allowed to flush once a year.
That's it. The Super Siphon itself once primed initially at the time the system is installed should require absolutely no maintenance at all.
We are aware of one installation that received no maintenance for seven years before the field lines finally blocked up. The drainlayer simply opened the valves on the ends of the field lines and flushed them with pressure water, then shut the valves again and the system continued working perfectly with absolutely no damage to the fields whatsoever. By comparison, we have seen the dripperlines in secondary treatment system disposal fields fail that were not maintained within twelve months with the dripperlines all needing replacement.
4) No Power
There is no need for power, including the costs of getting power to some sites, the continued running costs associated with it and the issues of power reliablity and outages.
5) No Pumps
In the aggressive septic tank environment pump seals break down and the pumps usually need servicing or replacement after only five years.
6) No Alarm
There is no need for a high water alarm as it is a gravity dosed system and not prone to power outages or pump/float switch failure.
7) Environmentally Friendly
While the effluent from a primary dosed system is less treated effluent then effluent from a secondary system, it is filtered, given time to polish and settle, and carefully dose loaded for further treatment within the soil itself in the effluent field. Disposal of effluent to land is part of the natural organic cycle of life. It is claimed that one spoonful of healthy topsoil contains more organisms than there are people on earth. By dose loading and feeding the soil this colony of micro-organisms is healthy and able to take out pathogens etc. Typically effluent after passing through one metre of quality topsoil will be close to a drinking water standard.
A siphon dosed primary system is dead simple with very little to go wrong. This is in comparison with the sophisticated and highly complicated secondary treatment systems which require maintenance as little as every six months. It has been found that over time if secondary systems are not serviced, the quality of effluent can fall back to primary levels or below.