Septic Tank | Sewerage Waste Disposal

By: Roto Trade Industries  12-08-2011
Keywords: Cement, Septic tank

The term “septic” refers to the anaerobic bacterial environment that develops in the tank. Once bacteria has developed, it decomposes the waste and is discharged into the tank.

Sewerage waste that is not decomposed by the anaerobic digestion, might have to be removed from the septic tank. If this process is not done, the septic tank fills up may over flow.

Disposing of oils, chemicals or any other non natural waste is not advised as this may block the septic tank or disturb the bacterial breakdown of the septic sewerage system.

Septic tank treatment is an easy and low maintenance way to deal with waste.

Download the Septic Tank brochure

S 600 lt – 1-2 Persons
1 140 mm 820 mm 950 mm 180 mm
S 1 000 lt – 1-4 Persons
1 700 mm 1 100 mm 950 mm 450 mm
S 1 750 lt – 1-7 Persons
(D) 1 500 mm - 1 201 mm 450 mm
S 2 500 lt – 1-10 Persons
2 150 mm 1 550 mm 1 280 mm 450 mm
S 5 000 lt – 1-20 Persons
2 200 mm 2 380 mm 1 260 mm 450 mm
S 8 000 lt – 1-35 Persons
(D) 1 850 mm
(L) 2 850 mm
- - 450 mm

Installation Instructions for the Septic Tank


Excavate the correct size hole in which to insert the manhole A 1:6 river and cement mix is required to cover at least 300mm across the base of the excavated hole. Make sure no solid objects are protruding from cement sand mix. Insert the manhole into the excavated hole and bed the manhole properly, by gently rocking the manhole backwards and forwards in the cement mix, making sure the manhole is accurately levelled.


When joining pipes to the septic tank manhole, it is easily done by using a water soap mix and ramming the required pipes home.


A 1:6 concrete sand mix should be carried out in 300mm thick layers from the base up to 100mm below the top of the septic tank manhole with the concrete filled lid in place on the manhole. The backfill material should preferably be sandy and slightly moist Each 300mm layer should be densely compacted to achieve 90% of modified A S H TO maximum dry density. For manholes deeper than 2.150mm or where a high water table is anticipated, backfill material must consist of a soil crete mix of 5% cement and 95% selected granular material.


Activation of the tank can either be done by using an activator or alternatively placing a dead chicken into the tank.


Connect the toilet outlet to the septic tank inlet with a 110mm PVC pipe. Connect the overflow or outlet to the French drain, making sure that it is not too close to household underground water supplies, e.g.: borehole.


When you flush the toilet, the content collects in the tank, therefore any solid waste product will float on the water.
The bacteria from the activator will dissolve the solid waste products and produce an almost clear water which settles at the bottom of the tank, which then flows out of the overflow and into the French drain.


No cigarette butts, chemical and or household cleaning products should be in the septic tank as it eliminates the bacteria and the consequences are that the chemical process will not be able to take place.

Keywords: Cement, Septic tank

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