Septic Tank Riser Kit - Septic Tank Sewage Treatment Systems - These offer a unconditionally clumsy method of treating sewage for properties which are not linked to mains drainage. Many septic tank systems throughout the world are never maintained and therefore attain not pretense properly and pollution govern laws exist to attempt to limit the amount of environmental and health risks they cause. These laws are getting tighter, and minimum standards have been put in place for further or replacement septic systems. In many cases you will need to install a sewage treatment tree-plant system instead. Always get the sewage system checked by a waste water system proficient prior to purchasing a property in order to prevent a pollution problem.
Types of Septic Tank Systems Available
There are various types of septic tank systems. They consist of an underground septic tank in differing shapes and sizes, which after that connects to a additional soil treatment system, usually a land drainage system in the form of a soakaway or drainfield, or a mound soakaway.
How a Septic Tank works
Raw sewage and waste water from baths, kitchens, etc. discharges into the tank, where the solids are separated from the liquid waste. Fats and oils float to the top of the tank and form a crust layer. Faeces and food scraps sink to the bottom of the tank and form a sludge layer. Anerobic bacteria which are natural colonisers in the tank "digest" this sludge by occurring to 70%.
The dirty septic water flows out of the tank to a soakaway or drainfield. Baffles or 'T' pipes in the tank keep encourage the in limbo crust and prevent it from entering the outlet of the tank. In order that the sludge and crust layers attain not become too deep, septic tanks should be emptied annually. This then prevents a sophisticated and sophisticated incorporation of suspended solids washing out into the soakaway. Solids can block the let breathe spaces in the soil drainage system, creating a drainage pain and the septic tank effluent will not be practiced to soak away or be treated by the natural soil bacteria.
Variations in Septic Tank systems
Traditional septic tanks comprise of two rectangular chambers: the first one physical 2/3 of the cumulative and the second 1/3, usually built in brick or concrete. Strict design rules are in place and septic tanks must be expected in accordance later than BS 6297 1983. The inlet pipe into the first chamber ends in a 'T' pipe which travels the length of the at least 450mm (18") under top water level (TWL), and the chamber must be a minimum of 1500mm (5'-0") deep from TWL. This first stage chamber is usually twice as long as it is wide. The pipe from the first chamber into the second chamber consists of an 'H' pipe and the bottom of the pipe is a min. of 300mm (12") under TWL in the first chamber and 450mm (18") under top water level (TWL) later than it enters the second chamber.This second stage chamber is usually square. The outlet pipe from the second chamber of the tank then consists of a 'T' pipe later than the bottom of the pipe 300mm (12") under TWL.
Vent pipes should be installed from the first and second chambers for venting the gases, mainly methane and hydrogen sulphide, that are produced by the sludge. mighty covers should always be placed unconditionally exceeding a septic tank to avoid children / animals falling into the tank. There are many cases of thcovers collapsing and many people have been killed as a result.
Nowadays, septic tanks are made in GRP and polyethylene which commonly are spherical in upset later than a narrow shaft at the top to a manhole arena level. These attain not fabricate the similar vibes of effluent as two chamber tanks and cannot be placed in stomach of many conversion units.
Care should be taken to ensure that problems will not occur due to the tank rising out of the ground, later than it is emptied in high water table sites. It is always advisable to install the tank later than a real surround.
Septic tank effluent still contains roughly 70% of the pollutants in the original sewage and needs further treatment in the soakaway to prevent a pollution problem.
Soakaways and Septic Drainfields
The Septic Tank by yourself provides the first ration of the sewage treatment process. The soakaway is the underground soil treatment system which uses aerobic bacteria found naturally in the arena to further treat the effluent. The soil type must be okay for a soakaway to pretense properly. Percolation tests are required to determine whether a septic tank soakaway is suitable. If the soil is clay, it is not okay for a soakaway and a drainage pain is inevitable. If you have this pain after that a sewage treatment tree-plant is the answer as they attain not need a soakaway.
The soakaway consists of either a series of trenches containing perforated pipe laid on and surrounded by stone, or an absorption bed, or a soakaway mound, all of which are linked to the septic tank outlet by a pipe. In all cases the soakaway must be a minimum of 1.2 metres above the water table or bedrock at all times. They must then be a minimum of 200 mm. under arena level to avoid septic effluent breaking to the surface. The pipes should be laid at a gradient of no more than 1:200 in a drainfield in order that the wastewater does not govern to the stop of the pipe, but is dispersed evenly. The perforations should be larger than 6mm (0.25") to avoid the biomatt, which forms in the trench, blocking the holes. The pipe cannot be the corrugated tubing type as used in land drains as this is not allowed, but must be the precise hermetic soakaway drainage pipe
The contaminants, pathogens, nutrients, and organic issue in the effluent are dispersed into the gravel where they are digested by aerobic bacteria.
On a slanting site, the effluent may flow into a series of drop boxes or manholes later than choice outlet to the adjacent pipeline set at a degrade level. Absorption beds are useful where way of being is limited, but they should by yourself be used as a second choice.
Sewage Drainage Mounds
A treatment mound is a raised soakaway system. Aggregates are used to raise the soakaway therefore that it is at least 1200mm (4'-0") above the seasonal high water table or bedrock. The mound system must be expected carefully, taking into account the topography of the site, the volume of septic tank effluent to be treated and the porosity of the topsoil to avoid failure of the system and boggy areas with reference to the base of the mound. The design cannot be guessed and must be curtains by a trained professional, using exam results and calculations.
I have seen badly expected mounds blast a hole through the side as they have been too little for the job.
Effluent is piped to a pumping station tank, where it is pumped in batches into the mound pipe-work. Septic mounds can see unconditionally handsome and can form ration of the landscaping of a garden. You are not allowed to tree-plant shrubs on top of them, but they can be planted with reference to their base.
Septic Tank Soakaway Pits
In the past, many septic tank systems used soakaway pits, although these pits are no longer sufficient under campaigner building regulations. They consisted of a large hole in the ground, entry at the bottom, either blocked round later than gaps with the blocks to allow seepage of the effluent into the soil, or straightforwardly holes filled later than stones. Some soakaway pits were made of large real rings later than gaps with the rings and the septic tank effluent was piped into them. They were always covered, usually later than a large real slab, but they were often a failure, as no calculations were undertaken to determine the porosity of the surrounding soil and they soon were filled later than septic effluent. The drains after that fill with the pit and the tank, which backs-up the entire septic system.
Site Conditions and Installation
Most sites in the UK are not okay for septic tank systems. Either the soil contains too much clay or is too porous, or the winter water table or bedrock is too close the surface. If the soil is clay, after that it will not soak the septic effluent away and if it is too rude it will not keep the effluent long sufficient for treatment. You could believe to be a non-electric sewage treatment tree-plant instead. Sometimes, it is realizable to adapt a septic system to engagement a basically improper site, but this requires careful planning and design by an expert. As a general rule, if the site has either insufficient soil depth, or the wrong type of soil, it is not okay for a septic system. Always entry your Building Inspector in the past deciding on a septic system.
The size of a septic system, both the tank and the soakaway area, is determined by the number of bedrooms in the home and porosity of the soakaway soil. A septic system cannot pretense if it is overloaded, therefore always bear in mind any plans you may have for extending the property in the past you believe to be on the size of the septic system. Increasing the size sophisticated results in a ruined garden.
Finally, always check later than the vibes Agency and you local Building govern in the past deciding on a septic system. They will have a unconditionally good idea as to whether it is likely to pretense in your place and could keep you thousands of pounds in replacing an improper septic installation.