WPL Diamond Domestic Compact Sewage treatment plant options: 1 to 55 people
The WPL Diamond range offers sewage treatment plants for properties that are not connected to mains drainage.
The WPL Diamond range includes:
- WPL Diamond DMS Compact Sewage Treatment Plant (1 to 20 people)
- WPL Diamond DMC Compact Sewage Treatment Plant (21 - 55 people)
Typical domestic uses for WPL Diamond include:
- Single houses (DMS) and small groups of houses (DMC) max eqv. 55 people
- Replacement of septic tanks
Typical commercial uses include:
- Bed and breakfasts
- Farm shops
- Other rural businesses
WPL Diamond Plants:
- Minimal maintenance
- Low running cost
- No mechanical internal moving parts - requiring minimal annual maintenance, making it economical to run.
- Kind to the environment as the treatment process requires no chemicals
- Minimal visual impact as the plant is buried entirely underground
- No smells most other treatment plants have primary tanks which store settled solids and can emit odours
- Long emptying cycle
The continuous bacterial digestion treats wastewater to a standard that meets all normal Environment Agency consents and is LABC approved
How does the WPL Diamond treatment plant work?
- Wastewater enters the Diamond via the inlet pipe directly into the central aeration chamber
- The central aeration chamber empties into the bottom of the outer clarifier chamber
- A drop pipe releases air through a disc plate diffuser
- An upward flow of process fluid draws settled solids through the draft tube to discharge at the surface of the aeration chamber
- The design of the draft tube ensures complete mixing of oxygen with the sewage. Oxygenation allows aerobic organisms, that biologically degrade wastewater contaminants, to grow
- Gravity causes aerated solids to settle at the tank bottom where they are drawn back up through the draft tube
- Raw sewage displaces biological solids from the aeration chamber to the clarifier chamber. Quiescent conditions in the clarifier allow digested solids to settle at the base and return to the aeration chamber
- The clarified effluent flows up through the scum baffle and over the weir arrangement prior to discharge via the outlet pipe
How is the WPL Diamond treatment plant installed
- The WPL Diamond sits below ground and is straightforward to install often without the need for concrete backfill.
- A comprehensive installation manual is supplied with each plant, which you should read thoroughly prior to installation.
- We recommend that you use an experienced and qualified installer for details of those in your area, please contact a member of the WPL sales team.
The WPL Diamond range meets the following industry standards:
- CE marked, fully type tested and certificated in accordance with the mandatory European standard BS EN12566-3, and meets all current legislation under the Environmental Permitting Programme
- The Diamond is designed using the British Water Code of Practice Flows and Loads, to ensure correct sized tanks
- LABC approved, which means it has been assessed against Building Regulation requirements and can be installed without the need to have it signed off again by building control
- The WPL Diamond DMS & DMC sewage treatment range has been granted German DIBT approval number Z-55.31-426
This means it is the only compact sewage treatment plant not requiring a primary tank or pre-treatment in Germany, allowing the whole process to happen in one tank divided into two.
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Visit Storyboard: WPL Sewage Treatment Plant Do's and Don't
Simplifying the Domestic Wastewater Treatment Issues
Properties situated off the mains drainage require a form of wastewater treatment or an upgrade of the original installed solution. The variety of choice available can be daunting.
Previously, the wastewater from a remote property would have flowed to either a cesspool or a septic tank.
A cesspool is an underground holding tank with no outlet, which stores the wastewater until it is time to have it emptied.
A 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.
Present-day water usage means that cesspools are an expensive solution due to the frequency of emptying, whilst septic tanks are becoming increasingly unpopular due to the poor quality of the water discharged and the subsequent negative impact on the environment. This is why modern, small scale, wastewater treatment systems have become the preferred solution.
Most of these systems are based on biological treatment, consisting of digestion of the organic matter by highly efficient, oxygen reliant (aerobic) bacteria. The aerobic process provides treatment to a much higher standard than a septic tank, which means that the treated water can be discharged to a soakaway in less porous soil or, with permission from the environmental regulator, directly to a stream or river.
When planning a wastewater treatment solution, in most cases it is necessary to apply to the environmental regulator for consent to discharge.
The Environment Agency (EA) in England and Wales, the Scottish Environmental Protection Agency (SEPA) in Scotland and the Department of the Environment (DOE) in Ireland will set the required standard of water quality, typically based on the amounts of Biochemical Oxygen Demand (BOD), Suspended Solids (SS) and Ammoniacal Nitrogen (NH4) permitted in the treated water (final effluent).
This will provide guidance in the choice of treatment solution; in most cases, the standard will dictate the need for a package treatment plant.
The plant chosen should also be CE marked and conform to the building regulations (part H2 in the UK) and the new European standard EN12566-3, which describes the minimum requirements for small package sewage treatment plants.
With the regulatory issues satisfied further matters of cost, installation and maintenance should be considered. The cheapest system to buy will not necessarily be the most cost effective to install when the costs incurred for heavy machinery and the amounts of installation material required, as well as running costs determined by the emptying (de-sludging) intervals and the complexity of maintenance are considered.
When assessing the installation requirements, the regulations stipulate that the plant has to be installed at least seven metres away from any property. The shape of the treatment plant determines the size of hole required for the installation. For example, a conical shape will require less space in the ground and therefore the cost of digging and disposal of the dug out material will be lower than for a plant that is square or cylindrical.
The backfill material will need to be chosen to suit the manufacturer’s recommendations and prevailing ground conditions. Most tanks have to be fully encased in concrete, which raises the installation cost, but some are robustly manufactured and can be installed using pea gravel or shingle. Problems can arise in areas with a high ground water level, which may mean that the tank will need to be anchored into the ground or surrounded in concrete.
A large aspect of the installation process is the creation of a point of discharge into which the treated effluent can be dispersed. Discharge options include a sub-surface soakaway, raised bed soakaway, drainage ditch, seasonal soakaway, constructed wetland or a watercourse, all of which are designed to suit the conditions in the land and the ground water levels.
A soakaway is the environmentally preferred point of discharge because the treated effluent receives physical filtration and further biological treatment before it merges with the ground water, but the size and type of a soakaway must be calculated from the results of a percolation test and soil assessment.
The different manufacturers of package sewage treatment plants offer varying warranties on the plants and the additional machinery. Warranties on the products vary widely between manufacturers, therefore the research on the best warranty also is an important cost consideration. It is also crucial to consider the inner structure of the plant as plants with internal mechanical moving parts potentially create more problems than plants which have all mechanical moving parts externally. These are less exposed to failure and therefore ensure peace of mind.
Following the simple process of choice it will be easy to determine which wastewater treatment plant is the best for each job.
For more information contact WPL