Homemade Septic Tank - Septic Tank Sewage Treatment Systems - These manage to pay for a agreed inexpert method of treating sewage for properties which are not amalgamated to mains drainage. Many septic tank systems throughout the world are never maintained and thus realize not pretend properly and pollution manage laws exist to try to limit the amount of environmental and health risks they cause. These laws are getting tighter, and minimum standards have been put in area for further or replacement septic systems. In many cases you will need to install a sewage treatment tree-plant system instead. Always acquire the sewage system checked by a waste water system adroit 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 secondary soil treatment system, usually a house 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 not speaking from the liquid waste. Fats and oils float to the summit 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 in the works to 70%.
The filthy septic water flows out of the tank to a soakaway or drainfield. Baffles or 'T' pipes in the tank hold help the wandering crust and prevent it from entering the outlet of the tank. In order that the sludge and crust layers realize not become too deep, septic tanks should be emptied annually. This after that prevents a far ahead and far ahead inclusion of suspended solids washing out into the soakaway. Solids can block the ventilate spaces in the soil drainage system, creating a drainage misery and the septic tank effluent will not be skillful 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 monster 2/3 of the amassed and the second 1/3, usually built in brick or concrete. Strict design rules are in area and septic tanks must be intended in accordance bearing in mind BS 6297 1983. The inlet pipe into the first chamber ends in a 'T' pipe which travels alongside the at least 450mm (18") under summit 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 summit water level (TWL) bearing in mind it enters the second chamber.This second stage chamber is usually square. The outlet pipe from the second chamber of the tank after that consists of a 'T' pipe bearing in mind 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 agreed over a septic tank to avoid kids / 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 assume bearing in mind a narrow shaft at the summit to a manhole showground level. These realize not build the same atmosphere of effluent as two chamber tanks and cannot be placed in belly of many conversion units.
Care should be taken to ensure that problems will not occur due to the tank rising out of the ground, bearing in mind it is emptied in high water table sites. It is always advisable to install the tank bearing in mind a tangible surround.
Septic tank effluent yet contains practically 70% of the pollutants in the native sewage and needs further treatment in the soakaway to prevent a pollution problem.
Soakaways and Septic Drainfields
The Septic Tank deserted provides the first allowance of the sewage treatment process. The soakaway is the underground soil treatment system which uses aerobic bacteria found naturally in the showground to further treat the effluent. The soil type must be gratifying for a soakaway to pretend properly. Percolation tests are required to determine whether a septic tank soakaway is suitable. If the soil is clay, it is not gratifying for a soakaway and a drainage misery is inevitable. If you have this misery after that a sewage treatment tree-plant is the answer as they realize 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, every of which are amalgamated to the septic tank outlet by a pipe. In every cases the soakaway must be a minimum of 1.2 metres above the water table or bedrock at every times. They must after that be a minimum of 200 mm. under showground 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 manage 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 house drains as this is not allowed, but must be the exact unquestionable soakaway drainage pipe
The contaminants, pathogens, nutrients, and organic business in the effluent are dispersed into the gravel where they are digested by aerobic bacteria.
On a leaning site, the effluent may flow into a series of fall boxes or manholes bearing in mind complementary outlet to the next pipeline set at a humiliate level. Absorption beds are useful where declare is limited, but they should deserted be used as a second choice.
Sewage Drainage Mounds
A treatment mound is a raised soakaway system. Aggregates are used to lift the soakaway thus that it is at least 1200mm (4'-0") above the seasonal high water table or bedrock. The mound system must be intended 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 more or less the base of the mound. The design cannot be guessed and must be ended by a trained professional, using test results and calculations.
I have seen horribly intended 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 look agreed attractive and can form allowance of the landscaping of a garden. You are not allowed to tree-plant shrubs on summit of them, but they can be planted more or less their base.
Septic Tank Soakaway Pits
In the past, many septic tank systems used soakaway pits, although these pits are no longer plenty under objector building regulations. They consisted of a large hole in the ground, edit at the bottom, either blocked circular bearing in mind gaps amongst the blocks to permit seepage of the effluent into the soil, or helpfully holes filled bearing in mind stones. Some soakaway pits were made of large tangible rings bearing in mind gaps amongst the rings and the septic tank effluent was piped into them. They were always covered, usually bearing in mind a large tangible 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 bearing in mind septic effluent. The drains after that occupy amongst the pit and the tank, which backs-up the entire septic system.
Site Conditions and Installation
Most sites in the UK are not gratifying 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 indecent it will not hold the effluent long plenty for treatment. You could rule a non-electric sewage treatment tree-plant instead. Sometimes, it is realizable to familiarize a septic system to raid 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 gratifying for a septic system. Always edit 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 sure by the number of bedrooms in the house and porosity of the soakaway soil. A septic system cannot pretend if it is overloaded, thus always bear in mind any plans you may have for extending the property in the past you rule on the size of the septic system. Increasing the size far ahead results in a ruined garden.
Finally, always check bearing in mind the atmosphere Agency and you local Building manage in the past deciding on a septic system. They will have a agreed good idea as to whether it is likely to pretend in your area and could keep you thousands of pounds in replacing an improper septic installation.