Not sure which Treatment Plant to choose?
Choosing the right sewage system for the job can be a difficult process.
This guide helps you understand some of the features and benefits of most of the modern package treatment plants available.
Whilst there are many treatment plants on the market, I have chosen to review the following:
I would like to point out that I do not believe there is one "best" treatment plant, as some circumstances might point you towards one over another. I have written these reviews as a guide to help you establish the features and benefits of the main systems available.
Premier Tech ASP
The ASP (active sludge process) by Premier Tech is one of 3 conical shaped tanks for sale in the UK. However, what distinguishes it from the others is that is made from rotationally moulded Polyethylene. ASP treatment plants use Activated sludge. Active sludge is a term used to describe bacteria that freely float in the water. Unlike fixed biology system (where bacteria is grown on a media), active sludge systems have no media material in them. This can be seen as advantageous due to the fact that there is really nothing inside the tank. If an active sludge system was to be contaminated, it is easy to empty and start again.
Manufacturer: Premier Tech
WPL Diamond
The WPL Diamond utilises a conical design similarly to the Premier Tech ASP. The key difference is the tank is made from GRP (glass reinforced plastic). This is not a problem and I can’t knock the manufacturer of these tanks. It's hand made rather than machine made.
Just like the Premier Tech ASP, the WPL diamond uses active sludge to treat wastewater. Air enters the system via a blower housed in a separate box, which should be installed near the treatment plant. A loss of pressure alarm is included and warns the user in the event that the pressure from the air blower drops. Due to the construction the WPL diamond cannot have a pump within the tank, so if you need to lift the treated water to higher ground you will need to install a separate chamber.
All in all it's a robust treatment plant with a built in alarm.
Manufacturer: WPL
The Tricel Novo Utilises a 3 stage method of treating sewage. In brief, these stages are: Primary Settlement, Aeration/treatment and final clarification (with sludge return). Unlike active sludge systems, the Tricel uses filter material to allow a place for bacterial growth, the material is a honeycomb structure within the tank. We class this as fixed biology, or fixed culture. There are pros and cons to fixed media; on one hand, it is slightly better for allowing bacteria to live for longer period of time. However, there is a greater possibility of items clogging up in the material.
The Tricel tank is constructed using a compression moulding technique. This technique produces very good results, consequently the Tricel tank is very strong.
Visually, the Novo houses its air blower in a box above the tank, this does protrude out of the ground and can be a little unsightly, therefore it is important to locate the treatment plant in a position where this cannot be seen. Noise may also be a factor to consider as with any air driven system.
Manufacturer: Tricel
Best for: Tank Strength
The Clearwater E-Range treatment plant is simple and effective. Its process is slightly different than other systems. Waste water enters the settlement chamber where solids fall to the bottom of the tank, the liquid then enters the treatment chamber where it is lifted up and sprayed over the filter material continuously. Bacteria grow on the filter material and feed upon the contaminants. Producing water that is legal to discharge into a river or stream (like all EN tested treatment plants).
The E range is constructed using GRP (glass reinforced plastic). The system is relatively deep and with no earth holding it down it can be prone to buoyant forces. For this reason installation must be carried out carefully and in accordance with the manual, specifically in clay soils and potential high water table areas. The air blower is housed in a box installed next to the treatment plant. Whilst I’m not a huge fan of external blower boxes, it does provide the opportunity to tuck that away somewhere that would shield noise, or replace the box for a brick built chamber. Maintenance is simple but recommended annually (as with all treatment plants).
Manufacturer: Clearwater pollution control
The Solido Smart utilises SBR technology which is commonly used across Europe, and a preferred method in Germany. SBR stands for Sequence Batch Reactor. Rather than continuously treating waste, the Solido Smart treats a batch at a time. This method of treatment produces very clean water with very low power.
This treatment plant is a single chamber system, all of the waste is digested. Like any system it needs to be de-sludged once a year, however when de-sludging, you are removing an over population of bacteria rather than accumulated solids (as these are digested).
Unique in its design, the air blower is housed in a sealed “capsule” under the lid, in the neck of the tank, fresh air is sucked in directly to the capsule by a small pipe that needs to be installed next to the tank. This provides a very stable environment for the air blower as it is not exposed to the moist air in the chamber.
Manufacturer: Premier Tech
Best for: Energy and Noise levels
The Klargester Biodisc is a mainstay in the sewage industry. Offering stabilised treatment, very low noise levels and with arguably the most installations out of all the treatment plants in the market, it is no wonder many people opt for this treatment system.
The treatment occurs on the discs inside the chamber, bacteria live on the discs which slowly rotate - semi submersed in the wastewater. As the bacteria live on a media (the discs) this is classed as a fixed biology treatment plant (the bacteria is fixed to the media as apposed to freely floating in the water). We would also class this as an RBC (rotating biological contractor).
Manufacturer: Klargester
Best for: Noise levels
The best treatment plant for noise levels and energy consumption is the Solido Smart, Its low levels of energy, and silent treatment, combined with its shallow installation make it a perfect choice for a domestic installation. However, it is not the cheapest system available, and many service companies unfortunately don't understand SBR treatment so ensure you have someone local that does actually understand it. Should you be installing a treatment plant and don't know anyone to look after it, the Biodisc is a great option, it also offers flow balancing to help stabilise the flow going through the plant.
If you want simplicity then the Tricel system is good, and it still has a low profile, therefore it is relatively shallow to install. However, it has a blower housed above the tank so you should consider locating it away from the house to avoid disturbance. I would personally swap out the blower provided with the plant with something more common to make parts easier to get hold of. This can be done as and when the blower needs replacing.
The ASP and Clearwater E-Range are not bad choices if price is a real factor, however you must consider digging depth, noise and visual appearance if opting for one of these treatment plants.
When selecting a treatment plant, it is advisable to talk to a few installers and service companies who are local to you. A Professional installer will service the system for you. Consequently, they may have a lot of experience with a certain model which would be advantageous if anything ever needs to be repaired. Be cautious of the installer that just says "this is the best" treatment plant, as there is no one treatment plant that is "the best" make your selection of installer as wisely as you make your selection of treatment plant and get a few opinions.
At this stage, it should also be mentioned at this stage, that you can often convert your existing septic tank into a treatment plant, an option many installers wont tell you (especially if they are a groundworker posing as, or trying to be a professional sewage company).
Buying from a specialist rather than just a drainage shop is also advisable as they can advise you on a wider range of information like regulations. Purchasing a treatment plant from a company local to you that can offer commissioning and support is also a good option.