Browse F.A.Q. Topics
- Buying from WPL Ltd2
- Care & Maintenance6
- Installation & Design6
- Regulations & Approvals4
Buying from WPL Ltd
Can I buy a WPL Diamond direct from WPL?
Contact us to discuss the best route to buying a WPL Diamond wastewater (sewage) treatment plant. Make an on-line enquiry or call us on +44 (0) 2392 242 600.
Why should I buy a WPL product?
WPL have been at the forefront of wastewater treatment technology for over 25 years, with international experience of technical design, quality of manufacture and supply of environmental waste water solutions.
Process Engineering Expertise.
Our process engineering expertise is valued by all of our customers; including the highly regulated water utilities, industrial and commercial users, right through to individual home owners, each equally as deserving of the highest quality standards. WPL is diligent in ensuring our customers’ sites are environmentally compliant and that the right level of protection is in place.
Standard products and bespoke package treatment systems.
We offer a comprehensive range of standard products that can deliver cost-effective onsite treatment of wastewater at even the most challenging sites. Our bespoke packaged treatment systems, designed by an expert team of process engineers and manufactured at our dedicated UK facility, can meet customers’ specific requirements in terms of whole-life cost, physical footprint, site access and discharge consents.
Discover more about WPL Ltd
Care & Maintenance
Where can spare parts be obtained?
Original spare parts for the small WPL Diamond package wastewater (sewage) treatment plant are available directly from our network of trusted independent experts or the manufacturer (WPL Ltd). For further information, please send us an enquiry or contact us on +44 (0) 2392 242 600.
What can I put in my domestic wastewater (sewage) treatment plant?
Ours Do’s and Don’ts of a small package wastewater (sewage) treatment plant, please think before you put anything down the sink, toilet or drains!
Do – cleaning products:
Do see the manufacturers’ recommended doses relevant to the hardness of your local water for household cleaning products; do try to use cleaning products little and often so the sewage treatment plant isn’t overloaded; do try to stick to the same washing, dishwasher and other cleaning products – the bacteria will work more efficiently with familiar products.
Do – washing machines:
Do use liquids, not powders in washing machines and dishwashers; do try to spread your clothes washing throughout the week.
Don’t – non-biodegradable products:
Don’t put sanitary towels, tampons, disposable nappies, baby wipes, cotton wool, incontinence pads, cotton buds, rubber products or other non-biodegradable products down the toilet.
Don’t – Kitchen:
Don’t pour fat, grease or cooking oil down the sink or drains.
Don’t – washing machines:
Don’t have a “washing day” – try to spread out your washing.
Don’t – chemical & liquid products:
Don’t use household bleach and strong chemicals indiscriminately or have a “spring cleaning” day; don’t tip bottles of medicine, mouth wash etc. down the toilet because these can harm the bacteria inside the wastewater (sewage) plant; don’t keep changing your brands of cleaners and washing powders; don’t pour any garden chemicals, paint or car engine oil down the drains.
Do domestic wastewater (sewage) treatment plants need service and maintenance?
Yes, all wastewater (sewage) treatment plants will need service and maintenance in order to ensure an efficient and reliable product. Please go to our useful documents page to download our Operations and Maintenance manual.
What is being checked during a service?
Your service engineer will carry out a full check on the plant, ensuring that your wastewater (sewage) treatment plant is operating correctly and checking and/or advising on the levels of sludge. For further information, please send us an enquiry or contact us on +44 (0) 2392 242 600.
What kind of guarantee does WPL provide?
All small WPL Diamond packaged wastewater (sewage) treatment products are supplied with a lifetime process guarantee from the date of delivery, ensuring you peace of mind. Warranty on the WPL Diamond tank is 25 years with two years on the air blowers. This is subject to consistent influent conditions and regular plant maintenance as per the manufacturer’s instructions. These guarantees are all subject to our terms and conditions. For more information please see our Service, Maintenance and Parts page.
What happens if I sell my house after installing a WPL Diamond wastewater (sewage) treatment plant?
According to the Environment Agency in England, if you sell your property, the new owner must be informed of your wastewater (sewage) treatment plant in writing. The information in your writing must include: a description of the treatment system and drainage system; the location of the main parts of the treatment system, drainage system and discharge point; details of any changes made to the treatment system and drainage system; details of how the treatment system and drainage system should be maintained, and the maintenance manual and records if you have them.
For further information, please contact the Scottish Protection Agency here.
For further information, please contact Natural Resources Wales here.
For further information, please contact Ireland Environment Protection Agency here.
Installation & Design
How are domestic wastewater/sewage treatment plants installed?
Our small WPL Diamond package wastewater (sewage) treatment plants are designed to sit below ground. A comprehensive installation manual is supplied with each plant, which you should read thoroughly prior to specification and installation.
We also recommend that you use an experienced and qualified installer. We see our network of independent installation experts as an extension of our own team. For further information, please send us an enquiry or contact us on +44 (0) 2392 242 600. Please watch our installation video of the compact, domestic WPL Diamond package wastewater treatment plant
What is a percolation test?
A percolation test is required for a soakaway to assess how much water can drain away through the subsoil. This is performed by an experienced site surveyor who excavates a small area of subsoil to monitor. We advise this test is taken prior to a wastewater (sewage) treatment plant being installed.
How will I know if I have a high water table area?
This can be determined by digging a trial hole and leaving it open for 48 hours for a site assessment. If you would like to request a visit from an independent expert in order to carry out this assessment, please make an enquiry or contact us on +44 (0)23 92242 600. Please check your local environment agency (England, Scotland, Wales and Northern Ireland) for regulations.
When to use External Pump Chamber (EPC)
If the location of the WPL Diamond plant is on an incline, in a highwater table area or a long distance away from the designated discharge point (ie: soakaway/water course/ditch) the final effluent may require pumping. The WPL Diamond range can be specified with an EPC which can deliver up to 100 litres per minute of effluent at a head of 4m. The external pump chamber (EPC) can be simply retro-fitted and is easy to maintain.
Will my wastewater (sewage) treatment plant be surrounded by concrete?
If installing a package wastewater (sewage) treatment plant in an excavation that allows water to enter (a high water table), this installation must be backfilled using a dry lean concrete mix or alternatively pea shingle if not a high water table. For more information please refer to the installation manual or contact us.
What is the British Water Code of Practice for Flows and Loads?
Flows and Loads is the Sizing Criteria, Treatment Capacity for Small Wastewater package treatment plants. This code of practice was prepared by the British Water Package Sewage Treatment Plant Focus Group comprising manufacturers, suppliers and service companies of all types of small wastewater treatment systems.
This code of practice provides a table of loadings which allows the total daily sewage load from properties to be calculated and it is recommended that all designers should use this table when sizing and designing non-mains sewage treatment systems. The flows and loads values given represent current best knowledge within the UK but may change with time in line with per capita water use.
The WPL Diamond wastewater (sewage) treatment range is designed using the British Water code of practice flows and loads, to ensure the tank is sized correctly.
Convenor of the British Water Package Sewage Treatment Plant Forum
Andrew Baird, technical director for WPL, is the convener of the British Water Packaged Treatment Plant Forum. The forum advises on standards and on regulation, and provides a way for the industry to lobby for unified standards and improved training. Andrew Baird, who has over 27 years’ experience in the water industry, is the regulatory expert for WPL, which specialises in custom-made packaged wastewater treatment plants. WPL Ltd is a member of British Water.
Want to know more?
Discover more about the British Water Package Sewage Treatment Plant Forum.
Discover more about British Water codes of practice.
How long does it take for a wastewater (sewage) treatment plant to start working?
Your newly installed wastewater (sewage) treatment plant can be used immediately! The biological process can take between 6-8 weeks to start working.
What quality of water (final effluent) is produced?
Water quality is defined by the level of three pollutants that are present in the effluent leaving the treatment plant. The three pollutants are (1) Biological Oxygen Demand (BOD); (2) Suspended Solids (SS); (3) Ammonia (AMM-N). These measurements are expressed in milligrams per litre e.g. 20mg/l (BOD), 30mg/l (SS), 20gm/l (AMM-N) – 20:30:20.
The WPL Diamond
WPL Diamond package wastewater (sewage) treatment range treats wastewater to a 95% standard of BOD, SS, and AMM-N. This is subject to the correct installation, consistent influent conditions and regular plant maintenance as per the manufacturers’ instructions. For further information or to arrange for a visit from one of our independent experts, please either fill out an enquiry form or call us on +44 (0)23 92242 600.
Where can I discharge to?
The treated final effluent from your package wastewater treatment plant can be discharged in to a water course, drainage ditch or soakaway with Environmental Agency approval. Please check your local environment agency (England, Scotland, Wales and Northern Ireland) for regulations.
WPL Diamond Range
The high quality WPL Diamond range is CE marked, fully type tested and certificated in accordance with the mandatory European standard BS EN12566-3 2014 for small wastewater treatment systems. Performance tested at an independent accredited facility in Aachen, Germany by PIA Institute for Wastewater Technology. See our WPL Diamond BS EN12566-3 2014 certificate.
Regulations & Approvals
Do domestic wastewater (sewage) treatment plants have to comply with European standard regulations?
Yes, all small domestic wastewater (sewage) treatment plants up to 50 persons must, by European standard regulations, be fully type tested and certified with the CE Mark in accordance with EN12566-3.
WPL Diamond Range
The high quality WPL Diamond package wastewater (sewage) treatment range is CE marked, fully type tested and certificated in accordance with the mandatory European standard BS EN12566-3 2014 for small wastewater treatment systems. Performance tested at an independent accredited facility in Aachen, Germany by PIA Institute for Wastewater Technology. See our WPL Diamond BS EN12566-3 2014 certificate.
Who is my local environment agency?
Is approval required to install a small domestic wastewater (sewage) treatment plant?
General binding rules state that your small wastewater (sewage) treatment system must meet the relevant British Standard in force at the time of installation. The standards currently in force for new systems are BS EN 12566-3 for small wastewater (sewage) treatment plants.
Your small package wastewater (sewage) treatment plant meets the British Standard in place at the time of installation if: it has a CE mark; the manual or other documentation that came with your tank or treatment plant has a certificate of compliance with a British Standard; it’s on British Water’s list of approved equipment. You can also ask the company that installed your equipment to confirm that it complies with the British Standard that was in place at the time the equipment was installed.
WPL domestic package wastewater treatment
All of the plants within the WPL domestic package wastewater (sewage) treatment range will be eligible to apply for an exemption to the environmental permit enforced by the Environment Agency (EA) in England. The EA will inform applicants if they are not eligible for a registration and therefore require a permit.
If you have a small package wastewater (sewage) treatment plant on your property in Scotland, it must additionally be registered with the Scottish Protection Agency. This must be presented when a new property is being built or an existing property changes hands. For further information, please contact the Scottish Protection Agency.
If you have a small package wastewater (sewage) treatment plant on your property in Wales, it must additionally be registered with Natural Resources Wales. For further information, please contact Natural Resources Wales.
For further information, please contact Ireland Environment Protection Agency.
How far from a building should a domestic wastewater (sewage) treatment plant be sited?
England. Environment Agency Building Regulations (Part H-H2 Package Sewage Treatment Works) state that all wastewater (sewage) treatment plants should be sited 7m-10m from any inhabited part of the property. The building control officer for the site will make the final decision on exactly how far the plant should be sited. If the discharge is to a soakaway a sampling chamber must be provided before the soakaway. Soakaway drains must be constructed in the aerobic soil layer, i.e. within 700mm of ground level. Please visit the Planning Portal website for further information.
My property is not connected to mains drainage what are my options?
Most domestic household wastewater (sewage) flows away through a series of sewers and is treated at a large-scale municipal treatment works. If your house is in a remote or isolated location where no “mains” drainage is available, options such as cesspools, septic tanks or sewage treatment plants are available.
Cesspool: Is an underground holding tank with no outlet, which stores the wastewater until it is full and requires emptying. A cesspool is expensive to operate as it requires regular (de-sludging) emptying. It is only considered as a permanent solution when no other options are available.
Septic tank: Provides partial treatment, settlement and separation of the solid waste and has an outlet pipe, normally discharging to a sub-surface soakaway or ditch. Septic tanks are discouraged because of the poor quality of what is discharged. For more information
Septic tank regulation changes: If you have a septic tank (lower wastewater quality standard) that discharges directly to a surface water such as a river or stream, you will need to replace or upgrade your treatment system by 1 January 2020, or when you sell your property if before this date. Unlike septic tanks and some small sewage treatment plants (also known as a package treatment plants) on the market, the WPL Diamond has an added advantage of a higher quality treatment process which allows more discharge options. For more information please look at the General binding rules – small sewage discharge to a surface water.
Package wastewater (sewage) treatment plant: Is an aerated system that provides significant biological breakdown of the organic and chemical contaminants. Package wastewater treatment systems “clean” the wastewater significantly, which permits discharge into less porous soils, smaller soakaways, drainage ditches and water courses.
What is a soakaway?: This is a means by which the treated water is dispersed into the ground, where it is physically filtered and further biologically treated naturally, before it combines with the natural groundwater – ultimately, our drinking water! This is why it is important the waste water complies to regulatory standards.
What goes in to my wastewater treatment system?: All of the water from your property, which includes waste water from sinks, dishwashers, washing machines, showers, baths, bidets and of course toilet waste.
Compliance: It is a criminal offence to knowingly cause pollution. A wastewater (sewage) treatment plant under 50 population needs to be compliant to EN12566-3 in the UK.
In Scotland and Wales you need:
- compliant sewage treatment plant
- consent to discharge permit
The compact WPL Diamond package wastewater (sewage) treatment plant range is specifically designed for properties without a connection to mains drainage and is supplied in a range of sizes
Where can I locate my wastewater treatment plant?: Building regulations recommend that a wastewater (sewage) treatment plant should be above or out of any area liable to flood. This is not always possible, therefore you can install a wastewater (sewage) treatment plant where cars are present such as a driveway – considerations should be given to when a vehicle passes over or near a plant. WPL recommends contacting a reputable installation professional when planning to install an off mains drainage wastewater (sewage) treatment plant.
Will the wastewater treatment plant obscure my view?: The WPL Diamond system is completely below ground, with flushest lid on the market to blend in with your landscape.
What about installation? Considerations include:
- siting e.g. any flood plain issues, driveway (traffic) option
- ground water table (especially in winter)
- how to off load your plant
- mechanical digger size
- base and backfill material including amount and type
- electrical requirement and installation
- depth of pipework in relation to inlet and outlet of treatment system
- noise – sewage treatment plants are not silent
WPL Diamond wastewater (sewage) treatment plants are easy to install. Its compact design requires less excavation to install compared to other plants, and in some cases no concrete backfill is needed. WPL recommends you use a qualified and experienced installation professional when considering a new or upgraded (inc septic tank replacement) wastewater (sewage) treatment plant.
What about the environment?: The WPL Diamond wastewater (sewage) treatment plants require no chemicals, and is therefore kind to the environment! And the final effluent can be safely discharged directly to a soakaway, watercourse or ditch.
What about maintenance?: The WPL Diamond wastewater (sewage) treatment plant has no internal electrical or mechanical moving parts within the tank, which makes it one of the most reliable plants on the market and requires minimal maintenance. All WPL Diamond DMS tanks come with 25 years warranty.
Maintenance – qualified service engineer: WPL recommends servicing should be undertaken by a qualified service engineer accredited by British Water. WPL would be happy to put you in touch with a local company.
Will my wastewater (sewage) treatment plant smell?: If a wastewater (sewage) treatment plant is installed and maintained properly there should be virtually no odours
Where can I find a professional to install and maintain my plant?: Our trusted network of independent domestic wastewater (sewage) treatment professionals supply expert advice on compliance and guidelines; whilst also providing installation, maintenance, servicing and parts. WPL would be happy to put you in touch with a local company.
What is domestic wastewater?
Domestic wastewater tends to originate from plumbing fixtures and appliances. This can include waste from toilets, dish washing, laundry, bath, shower and any other liquid waste produced within the household.
What is the difference between a septic tank and a package wastewater (sewage) treatment plant?
Unlike the traditional septic tanks, the modern package wastewater (sewage) treatment plants are designed with an aerated process for todays’ increased volume of water usage in everyday life.
Septic tank: Typically, a septic tank is found underground, receiving untreated wastewater (sewage) from a property and allowing the heavier solids to settle at the bottom whilst the effluent rises to the top. Naturally occurring bacteria helps the system break down the solids and sludge, with the remaining liquids flowing out of the tank into a drainage field. Septic tanks only provide partial treatment: settlement and separation of the solid waste and will normally discharge to a sub-surface soakaway or ditch.
Small package wastewater treatment plant: On the other hand, a small package wastewater (sewage) treatment plant provides significant biological breakdown of the organic and chemical contaminants by using air to circulate and treat the contaminants to a much higher standard than a septic tank. Package wastewater (sewage) treatment systems “clean” the wastewater significantly, which permits effluent discharge into less porous soils,effluent can then be discharged into a water course, drainage ditches and a soakaway. Please check your local environment agency (England, Scotland, Wales and Northern Ireland) for regulations.
WPL Diamond: The small WPL Diamond package wastewater (sewage) treatment plant has an added advantage of a high quality process in a compact, single tank which is easy to install and maintain. The successfully treated liquid that is discharged from the WPL Diamond wastewater treatment plant is of a higher quality standard than a septic tank. This means that our Diamond wastewater treatment plant will help to prevent your soakaway from blocking. If discharging in to a running water course, our WPL Diamond wastewater can help to reduce your environmental impact.
Rules for existing and new treatment systems – regulation changes: If you have a septic tank (lower treated liquid quality) that discharges directly to a surface water such as a river or stream, you will need to replace or upgrade your treatment system by 1 January 2020, or when you sell your property if before this date. Unlike septic tanks and some small sewage treatment plants (also known as a package treatment plants) on the market, the WPL Diamond has an added advantage of a higher quality treatment process which allows more discharge options. For more information please read the General binding rules – small sewage discharge to a surface water.
Typical uses of a WPL Diamond DMS – 1 up to 20 people equivalent
Domestic uses can include:
Single houses and replacement of septic tanks.
Commercial uses can include:
Bed and breakfasts; small commercial buildings and offices; small retail such as farm shops. If your property is not connected to mains sewer, wastewater (sewage) can be treated by the below ground discreet WPL Diamond DMS range, designed for properties of 1 up to 20 population equivalent.
Our WPL Diamond DMS package wastewater treatment plant is ideal for new builds and replacement of existing septic tank systems and package sewage treatment plants.
Typical uses of a WPL Diamond DMC – 21 up to 55 people equivalent
Domestic uses can include:
Single houses, small groups of houses, with a maximum population equivalent of 55 persons.
Commercial uses can include:
Commercial buildings and offices; stately homes and country estates; small hotels and bed and breakfasts; small retail such as farm shops; small villages, rural communities and housing associations. The below ground robust WPL Diamond DMC package (sewage) wastewater treatment range is for properties of 21 up to 55 population equivalent, where mains drainage is unavailable.
Our WPL Diamond DMC package wastewater treatment plant is ideal for new builds and replacement of existing septic tank systems and package sewage treatment plants.
Where can I find technical information about the WPL Diamond Range?
Technical specification tables for the WPL Diamond package wastewater (sewage) treatment range can be found in the support section of this website. Please go to Technical information.