frequently asked questions

FAQ - Frequently asked Questions about Sewage Treatment

To speak to one of our agents online about Frequently asked questions, click here

Find below the list of most Frequently asked questions regarding sewage treatment systems (FAQ – Questions about Sewage Treatment) and the Tricel range of reliable solutions.

Questions about Sewage Treatment

wasterwater treatment questions

Tricel Novo Vitae: Both are wastewater treament plant solutions manufactured by Tricel. Wastewater treatment plants offer a superior quality of treatment. For example, the Tricel Novo comprises of three independent wastewater treatment zones and offers an average of efficiency of 95.9% BOD removal.
This is a higher treatment standard than the effluent from a septic tank. Please note: all wastewater treatment plants used in Ireland must comply with the EN12566-3 standard and all septic tanks must comply with the EN12566-1 standard..

Tricel Vento: The septic tank from Tricel is manufactured as a primary treatment. Designed for the settlement of your effluent. This product may need an additional treatment like the Sandcel or Puraflo.

Domestic wastewater refers to all wastewater generated within the home, including waste from sinks, showers, baths, and toilets. 

The rainwater should never mix with the wastewater and should be disposed of in a separate soakaway.

Tricel Novo 

PE represents the initials of Population Equivalent. Population equivalent: conversion value which aims at expressing non-domestic applications in terms of domestic loading based on 1 person creates 60 g/day BOD5 and 150l/day. (Code of Practice: Wastewater Treatment and Disposal Systems Serving Single Houses (p.e. < 10), EPA)

A wastewater treatment plant treats the wastewater to a better quality, typically 20 times cleaner than a septic tank.

The choice will depend on a few factors, one being the subsurface value (or percolation value) and the other the depth of subsoil on the given site This is determined during the site assessment, which is a part of the overall site suitability test conducted by a qualified site assessor.

For more information, please refer to the 2021 Code of practice Section 6.4

Contact an engineer or site assessor to conduct a site survey and percolation test. Based on the results, our team is there to answer your questions, discuss your project, and do site visits.

Contact us.

Most Tricel products have a warranty. To discover all the guarantees on our products, as well as on the internal parts, consult our dedicated product pages.

The Tricel wastewater treatment plants comply with the European Standard EN12566, S.R. 66, and with the Environmental Protection Agency (EPA) Code of Practice. Click below for more details about the certifications.

operational questions

The Tricel wastewater treatment plant is a submerged aeration plant, and it’s divided into three chambers.

First chamber

 Solids are settled in this chamber, removing heavy substances. The effluent enters the primary settlement chamber. Settlement occurs when the heavier solids drop out of the wastewater and settle to the bottom of the tank to create sludge, and the lighter solids float to the top of the water to form a  scum. The top layer acts as a seal and stops odours from escaping. This chamber separates up to 70% of the solids present.


Second chamber

Next is the aeration chamber, where masses of naturally occurring bacteria inhabit specially designed plastic filter media. The bacteria feed on the waste removing it from the liquid. A continuous air supply from a low pressure, high-volume compressor in the top section of the unit sustains these bacteria. Wastewater passes through the filter media repeatedly, ensuring a very high treatment efficiency.


Third chamber

The wastewater then proceeds to the final settlement chamber. Any remaining minute bacterial particles separate from the wastewater within this chamber before discharge from the plant. This process slows the liquid’s velocity, allowing for any final trace impurities to settle into the bottom of the tank. A sludge return system then returns these impurities to the primary settlement chamber.

Learn more: Tricel Novo 

The required standards are 20:30:20 BOD, SS, NH4. All Tricel produces exceed the requirements when tested to En12566-3 and comply with SR66.

Learn more about our certification

Septic tanks or wastewater treatment plants should not receive surface water or rainwater.

Various plants are available from Tricel for different options. It is best to discuss this with your local council to determine a suitable solution.

Grease, fats, and oils should not be disposed of down the sink to maintain the efficient operation of your septic tank and WWTP. 

If your sewage contains high grease levels, you should install a grease trap before your sewage treatment plant or septic tank. Using a grease trap, the water flow rate into a plant is reduced, thus capturing the grease. The grease begins to float to the top when the sewage cools down.


There is a slight “hum” from the air compressor when standing close to the plant. When installed correctly, the noise level will not be a nuisance.

There should be no strong odour in the area adjacent to the plant. The presence of a strong odour would indicate that the plant is not working efficiently.

Ventilation must be in place this guarantees a fresh supply of air to the air blower. All vents should be checked to ensure they are not blocked or obscured. Also, investigate if the air blower is still “humming” if not, then this may be causing the issue of replacing the blower as soon as possible to resume the treatment process.

The plant should not be affected by a temporary power outage. After a power cut, checking the plant to ensure it has restarted is essential. It may have an alarm after powering on, but it will fix itself after a few minutes.

In situations where gravity drainage cannot be used, pumped options are available The power outage shouldn’t last too long when you have pump options as power is required to remove the treated liquid. Please do not hesitate to contact us if you have any questions.

installation questions

A concrete base and surround are not required when site conditions are considered dry. However, a concrete surround is necessary if the site is considered wet or a 500mm/750mm riser is fitted. Depending on the conditions of your site, your engineer will recommend a suitable installation requirement.

The Tricel sewage treatment plant provides a comprehensive installation guide with each plant supplied. You should ensure that you are confident that you can meet requirements outlined in the guide before you attempt installation. Advice on specific site conditions etc. should be sought from your onsite engineer.

A minimum separation distance should be checked at this stage, as in Table 6.2 of the 2021 code of practice. Domestic wells should be given special consideration.

For more information:–enforcement/waste-water/2021_CodeofPractice_Web.pdf

This may be determined by digging a trial hole and leaving it open for 48 hours during the site assessment. Water level is measured from ground level.

The biomass may require up to 16 weeks to reach optimal purification, but it is usually achieved within four to eight weeks.

Divide watts by 1000 which gives Kw figure
Multiply that by 24(hrs) to give Kwhours
Deduce costs from your individual tariff
eg: 60w (Tricel Novo UK 6) / 1000 = 0.06Kw per hour x TARIFF.

The Tricel Novo UK6 has a 60w blower, it’s electrical consumption is similar to leaving a similar size lightbulb (60w) on all day and night.

Check our brochure for the details of which air blower is use for which Novo model.

Depending on your region you may be able to discharge directly into a watercourse or to a percolation area. Please consult your local council for more information on which option is suitable for you.

No, surface water/rainwater should be plumbed separately to the sewage treatment plant.

To maintain efficient operation of your septic tank and WWTP, it’s important that grease, fats and oil are not disposed of down the sink.

It is best practice to install a grease trap prior to your sewage treatment plant or septic tank particularly if sewage contains high levels of grease. A grease trap captures the grease by reducing the flow rate of the water into the plant. The sewage starts to cool down and the grease float to the top of the trap.

We recommend that Tricel Novo units have a consistent power supply.
Solar panels will only work with the Novo or any treatment system if there is a main backup or if the solar panels have a battery that ensures a consistent supply of electricity.

It is important:

1) to prevent surface water from entering the tank and overloading the system as this can inhibit growth of the bacteria and could reduce the effluent quality.

2) to prevent water getting into blower housing which can harm the control panel and the air blower.

Learn more about Tricel Novo risers.

maintenance questions

De-sludging is necessary when the sludge occupies 50% of the primary chamber. This is when the sludge is 700 mm deep. A licensed company should perform de-sludging intervals every year to prevent sludge buildup. Local councils should have a list of licensed contractors. De-sludging is the responsibility of the homeowner. For more information, please refer to the 2021 Code of practice Section 12.2:

Learn more : Desludging

After emptying (desludging) a Tricel Novo wastewater treatment plant, the primary settlement chamber (On left the illustration below) must be filled back with water immediately until level with the aeration chamber. During desludging, we remove only the sludge (Left below), and end chambers (Right below) must be left full. Ensure the desludging cover on top is repositioned to the unit.


How does a wastewater treatment plant work Tricel

Full service should be performed once a year on your Tricel Novo. A suitably trained professional should carry out every service and guarantee the plant’s efficiency is maintained.

If the alarm is beeping, it may indicate one of the following:

  • The air return pipe to the alarm is not returning an air signal.
  • Electrical fault.
  • The electrical panel is wet.
  • The compressor does not detect enough back pressure from the diffuser (for example, there is not enough water in the middle chamber, or there is damage to the air hose or fitting)
  • The compressor needs maintenance.
  • In all cases, you should call our office or one of our recommended maintenance -companies.

An audible and visual alarm is standard and will notify you if there is a problem with the air compressor and discharge pump (pumped plants only), but this does not replace regular inspections. We recommend a maintenance agreement with us to ensure the plant’s optimal performance. 

Tricel recommends that you maintain your device to the fullest. You are obliged by law to avoid all types of pollution or nuisances. Do not hesitate to contact us for more information on our service contracts. An annual maintenance contract may be offered.

Manuals & Specifications

View and download our brochure and technical information

Contact Us

Arrange a callback or email enquiry

Get in touch


Error: Contact form not found.