Septic Tanks - Suppliers, Systems, Products, Facts and Advice
Septic Tanks were the accepted method for sewage disposal and wastewater treatment in rural areas until the 1980's. They are now only usually acceptable for populations of up to 15 people and only in certain areas.
There are hundreds of thousands of septic tanks in the UK and from 1st January, 2015, they must all comply with the Environment Agency General Binding Rules.
Septic Systems give a very crude method of treating sewage for properties which are not connected to mains drainage. Many septic tanks throughout the world are never maintained and so do not work properly and pollution control 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 new or repacement septic tanks. Always get septic systems checked by a wastewater expert before purchasing a property to prevent a pollution problem.
Most of our telephone calls are due to existing septic systems that no longer work. This can be due to faults and deteriorations in the tank, but nine times out of ten it is due to soakaway drainfield failure. All septic tank soakaways are doomed to fail sooner or later. When soakaways fail, it is catastrophic for the owner as the entire system backs up and they can no longer use the toilets, shower, etc without thinking of the amount of water that they are putting into an already overloaded system. The tank may even have to be emptied once a week, if the soakaway failure is advanced, at a cost of around £150 a time. The 'onion' shaped ones seem to cause soakaway failures quicker than the traditional 2 chamber tanks. Unfortunately, they are also cheaper, so tend to be more common.
As we often say to people, "A house without sanitation is just a shed".
Always have the system inspected prior to purchase of a property, but always budget for replacement of the system with a sewage treatment plant sometime in the future, as environmental regulations become tighter. Sewage treatment plant soakaways also do not tend to fail as the plants are far more efficient.
Take a look at the webpages opposite for further information.
Telephone us if you have any questions regarding any aspect of sewage treatment. You will receive completely impartial advice based on 25 years in the wastewater treatment industry.
There are various types of septic systems. They consist of an underground tank in differing shapes and sizes, which then connects to a secondary soil treatment system, usually a land drainage system in the form of a soakaway or drainfield, or a mound soakaway.
Raw sewage and wastewater from baths, kitchens, etc. discharges into the septic tank, where the solids are separated from the liquid waste. Fats and oils float to the top and form a crust layer. Faeces and food scraps sink to the bottom and form a sludge layer. Anerobic bacteria which are natural colonisers in the tank "digest" this sludge by up to 70%. The dirty septic water flows to a soakaway or drainfield. Baffles or 'T' pipes in the tank hold back the floating crust and prevent it from entering the outlet. In order that the sludge and crust layers do not become too deep, septic tanks should be emptied annually. This also prevents a higher and higher concentration of suspended solids washing out into the soakaway. Solids can block the air spaces in the soil drainage system, creating a drainage problem and the effluent will not be able to soak away or be treated by the natural soil bacteria.
Vent pipes should be installed from the first and second chambers for venting the gases, mainly methane and hydrogen sulphide, produced by the sludge. Strong covers should always be placed completely over the tank to avoid children / animals falling in. There are many cases of septic tank covers collapsing and many people have been killed as a result.
Onion or Traditional rectangular tanks?
Nowadays, septic tanks are made in GRP and polyethylene which commonly are spherical in shape with a narrow shaft at the top to a manhole cover at ground level. These tanks do not produce the same quality of effluent as traditional brick, concrete or GRP two chamber tanks and cannot be placed in front of many septic tank conversion units, including the FilterPod and BioKube.
Installation of the tanks
Further sewage treatment is always required