Sewage Treatment Works - How they work - How to choose a domestic system

There are basically 3 different types of domestic sewage treatment works:

Differences between the sewage treatment plants available

Checklist	Traditional 3 stage Plant	Extended Aeration Plant	Non-Electric Filter Systems
Electricity required	YES	YES	NO
Emptying Interval	3 to 12 months	2 to 4 years	2 to 4 years
Smelly Primary Tank	YES, with some	NO	NO
Internal Moving Parts	OFTEN (Biodiscs)	NO	NO
Ability to perform during intermittent use (holiday lets, etc)	SOME	NO	YES
Visually Intrusive	OFTEN	NO	NO
Expensive Servicing	OFTEN	SELDOM	NO
Warranty Period	1 to 25 years	Up to 30 years	10 years
Effluent Standard	OK to GOOD	OK	5 times cleaner than UK Standard

Questions to ask the sewage treatment works manufacturers

Does it require electricity?

All plants apart from Biorock sewage treatment plants require electricity to work.  Some require much more than others!  Make sure you ask what the average KW hours/year the plant uses BEFORE you buy it!  This is particularly important for the larger sewage treatment plants as the cost for a 100 person plant can be £12,000/year, depending on how it works.

How often should the sewage treatment plant be emptied?

Emptying is often the most expensive part of system running costs. Emptying intervals also depend on how it works.  All of the 3 stage package plants require emptying every 1 to 12 months as they don't digest the solids, but store them as sludge in the primary tank.  The extended aeration sewage treatment plants digest the solids as well and have a 1 to 5 yearly emptying interval, depending on the model. The BIOROCK has a 4 year emptying interval.

Can I have a copy of the full EN12566-3 2005 test RESULTS?

 

BEWARE as many sewage treatment plants for sale in the UK have NEVER been tested by anyone! 

Others, even some made by the leading names, which have passed the EN12566-3 2005 would NOT pass the UK Environment Agency standards which YOU have to adhere to!!  This is because the EN12566-3 2005 only tests the percentage reduction of pollutants in the final effluent, NOT the final effluent quality produced by the sewage equipment!  Yes, it is stupid as many sewage treatment plants which failed, during the test, to achieve the UK Royal Commission Standard of 20BOD:30S.S.:20NH3 on a 95 percentile basis have been given the EN Certification!   This is why many manufacturers will only offer the Test Conformity Certificate and not the test report! 

If they WON'T give you the test REPORT, DON'T buy the unit!!  

It is YOU that the Environment Agency prosecutes ( see Latest News) not the sewage equipment manufacturer! 

 

Does it have a Primary Settlement Tank?

 

If it does, then it is a 3 stage wastewater treatment plant as described above. Unvented UK Primary Settlement Tanks do not tend to be odourless as gases can escape through the sewage treatment unit lid, particulary when the bath, etc. is emptied, displacing air through the lid of the plant.  It is called Primary Settlement Tank Odour.  Ask if the PST is vented as part of the works! 

 

Does it rely on internal moving parts?

 

Moving parts wear out and sewage is very corrosive.  Replacement parts and labour can be very expensive for some plants. 

 

How thick is the fibreglass/polyethylene?

 

This can vary between plants from about 3mm to 8mm, depending on the make of unit. Obviously, the thicker the better as thin walled tanks can distort or crack under the pressure of groundwater. 

 

What do you see when the sewage treatment works is installed?

Some plants are an eyesore, either because the lids are enormous and protrude well above ground level, or because there are multiple large lids on view.  Some sewage treatment units have unsightly Kiosks containing compressors and timers etc.

How much is the annual servicing cost?

Servicing costs for sewage equipment also varies enormously, from £75.00 to over £300.00, depending the complexity of the unit. A general rule is, the simpler the treatment system works, the cheaper the service.

How long is the tank warranty?

This varies from 1 year to 30 years, depending on the plant manufacturer.

All sewage treatment plants, except for the Klargester Sigma, should be suitable for direct discharge to a ditch or watercourse, subject to Environment Agency Consent to discharge.  However, not all sewage equipment is designed for this type of disposal system.  Septic Tanks are NOT, and expensive soakaways, with a limited lifespan, must be constructed to dispose of all septic tank effluent.

You will need a PERMIT TO DISCHARGE from the Environment Agency to discharge to a watercourse.  It is not difficult to obtain and we will help you with the forms free of charge.

More sewage treatment works links

Aberdeen Sewage Treatment Works
Aldershot Sewage Treatment Works
Altrincham Sewage Treatment Works
Aylesbury Sewage Treatment Works
Banbury Sewage Treatment Works
Barnsley Sewage Treatment Works
Bath Sewage Treatment Works
Bathgate Sewage Treatment Works
Bedford Sewage Treatment Works
Bexley Sewage Treatment Works
Bexleyheath Sewage Treatment Works
Birmingham Sewage Treatment Works
Bolton Sewage Treatment Works
Bournemouth Sewage Treatment Works
Brighton Sewage Treatment Works
Bristol Sewage Treatment Works
Burton upon Trent Sewage Treatment Works
Bury Sewage Treatment Works
Bury St Edmunds Sewage Treatment Works
Camberley Sewage Treatment Works
Cannock Sewage Treatment Works
Cardiff Sewage Treatment Works
Carlisle Sewage Treatment Works
Chessington Sewage Treatment Works
Chester Sewage Treatment Works
Chesterfield Sewage Treatment Works
Chorley Sewage Treatment Works
Crawley Sewage Treatment Works
Dalkeith Sewage Treatment Works
Derby Sewage Treatment Works
Doncaster Sewage Treatment Works
Dorking Sewage Treatment Works
Durham Sewage Treatment Works
East Grinstead Sewage Treatment Works
Eastleigh Sewage Treatment Works
Edinburgh Sewage Treatment Works
Enfield Sewage Treatment Works
Epsom Sewage Treatment Works
Farnborough Sewage Treatment Works
Farnham Sewage Treatment Works
Gateshead Sewage Treatment Works
Gloucester Sewage Treatment Works
Godalming Sewage Treatment Works
Grantham Sewage Treatment Works
Gravesend Sewage Treatment Works
Grays Sewage Treatment Works
Guildford Sewage Treatment Works
Hastings Sewage Treatment Works
Hatfield Sewage Treatment Works
Haywards Heath Sewage Treatment Works
Hemel Hempstead Sewage Treatment Works
Hereford Sewage Treatment Works
High Wycombe Sewage Treatment Works
Horley Sewage Treatment Works
Horsham Sewage Treatment Works
Hove Sewage Treatment Works
Inverness Sewage Treatment Works
Ipswich Sewage Treatment Works
Kettering Sewage Treatment Works
Leatherhead Sewage Treatment Works
Leicester Sewage Treatment Works
Lichfield Sewage Treatment Works
Littlehampton Sewage Treatment Works
Liverpool Sewage Treatment Works
Livingston Sewage Treatment Works
Loughborough Sewage Treatment Works
Luton Sewage Treatment Works
Manchester Sewage Treatment Works
Mansfield Sewage Treatment Works
Milton Keynes Sewage Treatment Works
Musselburgh Sewage Treatment Works
New Malden Sewage Treatment Works
Newark on Trent Sewage Treatment Works
Newcastle upon Tyne Sewage Treatment Works
Newport Sewage Treatment Works
Northampton Sewage Treatment Works
Norwich Sewage Treatment Works
Plymouth Sewage Treatment Works
Poole Sewage Treatment Works
Preston Sewage Treatment Works
Purley Sewage Treatment Works
Redditch Sewage Treatment Works
Reigate Sewage Treatment Works
Romford Sewage Treatment Works
Rotherham Sewage Treatment Works
Salford Sewage Treatment Works
Sevenoaks Sewage Treatment Works
Sheffield Sewage Treatment Works
Slough Sewage Treatment Works
Solihull Sewage Treatment Works
South Queensferry Sewage Treatment Works
Southport Sewage Treatment Works
St Albans Sewage Treatment Works
St Helens Sewage Treatment Works
Stafford Sewage Treatment Works
Stockport Sewage Treatment Works
Stoke on Trent Sewage Treatment Works
Surbiton Sewage Treatment Works
Sutton Coldfield Sewage Treatment Works
Tamworth Sewage Treatment Works
Thornton Heath Sewage Treatment Works
Tonbridge Sewage Treatment Works
Tunbridge Wells Sewage Treatment Works
Wallington Sewage Treatment Works
Walsall Sewage Treatment Works
Warrington Sewage Treatment Works
Watford Sewage Treatment Works
Wellingborough Sewage Treatment Works
Winchester Sewage Treatment Works
Windsor Sewage Treatment Works
Witney Sewage Treatment Works
Woking Sewage Treatment Works
Wolverhampton Sewage Treatment Works
York Sewage Treatment Works

Waste Tech gives INDEPENDENT advice on all the above sewage treatment works and equipment