Fiberglass Septic Tanks - Septic Tank Sewage Treatment Systems - These offer a no question substandard method of treating sewage for properties which are not similar to mains drainage. Many septic tank systems throughout the world are never maintained and fittingly reach not be active 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 place for extra or replacement septic systems. In many cases you will obsession to install a sewage treatment reforest system instead. Always acquire the sewage system checked by a waste water system expert 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 subsidiary soil treatment system, usually a estate 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 on bad terms 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 happening to 70%.
The dirty septic water flows out of the tank to a soakaway or drainfield. Baffles or 'T' pipes in the tank keep back up the drifting crust and prevent it from entering the outlet of the tank. In order that the sludge and crust layers reach not become too deep, septic tanks should be emptied annually. This after that prevents a future and future engagement of suspended solids washing out into the soakaway. Solids can block the let breathe spaces in the soil drainage system, creating a drainage difficulty and the septic tank effluent will not be able 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 subconscious 2/3 of the total and the second 1/3, usually built in brick or concrete. Strict design rules are in place and septic tanks must be meant in accordance in imitation of BS 6297 1983. The inlet pipe into the first chamber ends in a 'T' pipe which travels all along 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) in imitation of 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 in imitation of 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 no question greater than 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 pretend to have in imitation of a narrow shaft at the summit to a manhole pitch level. These reach not manufacture the thesame air 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, in imitation of it is emptied in high water table sites. It is always advisable to install the tank in imitation of a concrete surround.
Septic tank effluent yet contains nearly 70% of the pollutants in the original sewage and needs extra treatment in the soakaway to prevent a pollution problem.
Soakaways and Septic Drainfields
The Septic Tank unaccompanied provides the first allocation of the sewage treatment process. The soakaway is the underground soil treatment system which uses aerobic bacteria found naturally in the pitch to extra treat the effluent. The soil type must be okay for a soakaway to be active 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 difficulty is inevitable. If you have this difficulty after that a sewage treatment reforest is the answer as they reach not obsession a soakaway.
The soakaway consists of either a series of trenches containing perforated pipe laid upon and surrounded by stone, or an absorption bed, or a soakaway mound, all of which are similar 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 after that be a minimum of 200 mm. under pitch 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 estate drains as this is not allowed, but must be the exact sealed soakaway drainage pipe
The contaminants, pathogens, nutrients, and organic concern 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 in imitation of substitute outlet to the neighboring pipeline set at a lower level. Absorption beds are useful where ventilate is limited, but they should unaccompanied be used as a second choice.
Sewage Drainage Mounds
A treatment mound is a raised soakaway system. Aggregates are used to raise the soakaway fittingly that it is at least 1200mm (4'-0") above the seasonal high water table or bedrock. The mound system must be meant 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 on the subject of the base of the mound. The design cannot be guessed and must be curtains by a trained professional, using test results and calculations.
I have seen awfully meant 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 no question attractive and can form allocation of the landscaping of a garden. You are not allowed to reforest shrubs upon summit of them, but they can be planted on the subject of their base.
Septic Tank Soakaway Pits
In the past, many septic tank systems used soakaway pits, although these pits are no longer sufficient under modern building regulations. They consisted of a large hole in the ground, entrance at the bottom, either blocked round in imitation of gaps in the middle of the blocks to permit seepage of the effluent into the soil, or comprehensibly holes filled in imitation of stones. Some soakaway pits were made of large concrete rings in imitation of gaps in the middle of the rings and the septic tank effluent was piped into them. They were always covered, usually in imitation of a large concrete 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 in imitation of septic effluent. The drains after that occupy in the middle of 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 indecent it will not keep the effluent long sufficient for treatment. You could declare a non-electric sewage treatment reforest instead. Sometimes, it is realistic to get used to a septic system to warfare a basically unsuitable site, but this requires cautious planning and design by an expert. As a general rule, if the site has either insufficient soil depth, or the incorrect type of soil, it is not okay for a septic system. Always entrance your Building Inspector past deciding upon 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 be active if it is overloaded, fittingly always bear in mind any plans you may have for extending the property past you declare upon the size of the septic system. Increasing the size future results in a ruined garden.
Finally, always check in imitation of the air Agency and you local Building manage past deciding upon a septic system. They will have a no question good idea as to whether it is likely to be active in your place and could keep you thousands of pounds in replacing an unsuitable septic installation.