Septic Sewage Systems

We are reviewing our Marketing Policy with regard to Septic Systems. Unfortunately, the average person knows nothing about septic waste water systems; any more than they know about the mechanics of their late model car.

Recently, we have been castigated by several large families because our Products did not measure up to their expectations. Either they have tanks that are too small or they are in clay soil or marshy [vlei] areas and expect that a small [1,500 lt] plastic ‘torpedo’ septic tank will digest their combined waste water and sewage. There is just no way that such a system will work. It defies basic science.

The sad thing – and we ‘feel’ for these customers, is that they have been advised by someone that the size of tank installed will be adequate [‘perfect’]. It is our experience that many architects, draughtsmen, builders, hardware retailers, tank manufacturers as well as [sadly] many municipal inspectors have scant knowledge of the limitations of septic systems

We are consistently being approached by clients who have totally inadequate septic tanks, but they wish to buy and apply our products in the hope that they will over -come their defective sewage systems. Sometimes our Products do solve their problem short term, but they may not work; long term – they cannot; and we end up losing credibility and being bad mouthed by the affected customer.

In future we will hesitate to supply customers:

1. Who send both grey and black water to their septic tank [hydraulic overload]
2. Have septic tanks of inadequate shape and size for the number of Residents living in the house [organic overload]
3. Have soakaways / French drains / leach-fields which are too small and are constructed  in unsuitable material. [causing the tank to surcharge/overflow

However, we will gladly offer advice to these unfortunate people, because we realise that they, and their original designer / builder / planning officer was unaware of the limitations that govern the successful operation of septic systems; and although it is, it’s not really the fault of the owner – ignorance is a reasonable excuse, and we will help to solve it as best we can.

A septic system is a very good [rural] sewage disposal devise, but it cannot cope with excessive loads. Usually the septic tank is too small.

Providing it is of a capacity sufficient to receive the load, and positioned in suitable soil, a septic system will work –well and trouble free -, for many years.

A septic tank should be cleaned and re-started every 15 – 25 yrs.
 
A tank that is ‘pumped’ frequently [once or twice a month sometimes] just does not have a chance of working, because each time it is ‘pumped’ most of the microbes essential for the degradation of sewage solids are lost to the recipient of the bulk effluent. [usually the local municipal ‘sewage works’]. This is progressive, until the tank becomes sterile.
Signage: From a cursory inspection of rural establishments, we are appalled at the lack of signage indicating a ‘septic tank’.  City dwellers do not know what septic tanks are

Most city dwellers are blissfully unaware of the limitations of these ‘anaerobic bio-digestors’ [because that is what a septic tank is], compared to a municipal [wwtw]  waste water treatment works, which is designed to treat ‘mixed’ [commercial & domestic] effluent

We can [and have] written and supplied signage indicating that only human bodily wastes and the toilet paper provided is to be flushed down the toilet bowl. ASK US

The Septic System Consists of:

1. An adequately designed and sized septic tank [minimum two chambers],
2. An overflow soakaway / frenchdrain / leachfield / grey water treatment plant.

‘Black’ water should never be re-used. It’s not safe: It is usually toxic

The ‘grey’ waste wash water [bathrooms, basins and laundry] should go directly to the soakaway. [or to a grey water treatment plant for garden re-use].

Only ‘black’ sewage waste water from the toilets and urinals and kitchen drainage goes to the septic tank

Calculation of load:  

1. We do this by evaluating the number of residents, which dictates the capacity of the tank [the number of bedrooms, bathrooms and toilets make no difference]
2. The permeability of the soil in which the soakaway is constructed – which dictates it’s relative size and length.
   

Invariably, we find that the equation has been calculated the other way around and the client/builder has decided upon the size of both the tank and the soak away or soak-pit [as is so frequently installed]; with no - or scant - regard for soil porosity Usually cost/bottom line considerations is the deciding factor.

Such systems often work trouble free for a couple of years, then they say ‘howzit’ and fail.; because they are inadequate for the load and too small So you call the Council to ‘pump’ the tank; and then your troubles really start in earnest.

Very few authorities have vacuum tankers with adequate ‘spate pumps’ [that will handle semi-solids]. They remove the liquid, but not the fat - usually in the soakaway - that is causing the blockage and overflow. Often there is a ‘run’ on municipal tanker services during the holiday seasons, and delays are inevitable, in addition to the accidental damage to gardens, the inconvenience and the odour.
 
Septic systems do not thrive under ‘feast and famine’ conditions. They are like diesel engines thriving under a constant load. If used for the odd week-end, you are advised to apply an additive [W-A-W] to ‘wake-up’ the microbes that are essential to degrade your sewage, and to boost them again when you leave the cottage. This can be done conveniently via the toilet bowl.                           

© Bob Hadley 21 Sep 2011