Care should be taken to make sure that problems will not occur due to the tank rising out with the ground, when it is actually emptied in high water table sites. It is always advisable to install the tank which has a concrete surround.
Septic tank effluent still contains about 70% of the pollutants in the primary sewage and needs further treatment inside soakaway to prevent a pollution problem.
Soakaways and Septic Drainfields
The Septic Tank only provides the first part of the sewage treatment process. The soakaway could be the underground soil treatment process which uses aerobic bacteria found naturally in the ground to further address the effluent. The soil type must be suitable for a soakaway to figure properly. Percolation tests are required to determine whether a septic tank soakaway is suitable. If the soil is usually clay, it is not suitable for a soakaway and a drainage problem is inevitable. If you have this issue then a sewage treatment plant could be the answer as they do not need a soakaway.
The soakaway consists of either several trenches containing perforated tube laid on and surrounded by stone, or a great absorption bed, or a soakaway mound, all of which are connected to this septic tank outlet by the pipe. In all cases your soakaway must be a minimum of 1. 2 metres above the pool table or bedrock at all times. They must also be at the least 200 mm. below ground level to avoid septic effluent breaking on the surface. The pipes should be laid for a gradient of no more than 1: 200 in a drainfield so that the wastewater does not run to the end of your pipe, but is distributed evenly. The perforations ought to be larger than 6mm (0. 25″) and avoid the biomatt, which forms inside trench, blocking the cry. The pipe cannot be the corrugated tubing type as applied to land drains as this is not allowed, but must become the correct solid soakaway drainage pipe
The toxic contamination, pathogens, nutrients, and organic matter inside effluent are dispersed in the gravel where they are generally digested by aerobic bacteria.
On some sort of sloping site, the effluent may flow into a series of drop boxes or manholes with another outlet to another pipeline set at a lesser level. Absorption beds are of help where space is reduced, but they should only use as a second selection.
Sewage Drainage Mounds
Cure mound is a raised soakaway system. Aggregates are used to boost the soakaway in order that it is at least 1200mm (4′-0″) above the seasonal high water table or bedrock. The mound system has to be designed carefully, taking into account the topography of this website, the volume of septic tank effluent being treated and the porosity in the topsoil to avoid failure with the system and boggy areas in the base of the mound. The design cannot be guessed and has to be done by a skilled professional, using test outcomes and calculations.
I have witnessed badly designed mounds blast a hole with the side as they are too small for the effort.
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