Frequently Asked Questions

We, at WCI, spend a lot of time answering a wide range of questions. We hope by posting some of the most commonly asked questions and answers, we can help you be more informed about your system. If you have a question that doesn`t appear below please contact us on 01984 623404 and we can assist you further.

Q. What is EN12566-3 2005? What should I know?


EN12566-3 2005 is the new standard for small package sewage treatment plants <50pe. It is a requirement for the CE mark which will become mandatory in the UK in 2013. The British Standards Institute have advised that, in their opinion, ONLY package plants which have the EN12566-3 2005 Certification are legal in the UK and only sewage treatment plants which have the EN 12566-3 Certificate are allowed by the Environment Agency for the Exemption Certificate. Conder plants have been designed and tested in accordance with BS EN 12566-3:2005 and produce an effluent Standard better than 20mg/l BOD; 30mg/l SS and 20mg/l NH3.

Q. What is the difference between a septic tank and a cess pool/pit?


A cesspool is a sealed underground tank where all the sewage from a property is stored. The Cesspool when full, at approximately monthly intervals, will need emptying by a tanker. A cesspool is only installed when all other system possibilities have been explored and rejected.

Q. My reeds look dead what should I do?


Reeds die back in the winter months and appear to be `dead`. Once spring has sprung new green growth will push through the old. If by late April you have seen no improvement contact WCI on 01984 623404 to arrange a site visit.

New reedbed growth

Q. How often should I empty my septic tank?


Most modern septic tanks (fibreglass onions) are designed for complete emptying/desludging every 12 months. I should note that the rate of desludging does depend on the number of people using the system and the working capacity of the tank.

Q. What can I and can`t I put down my drains when I am served by a private sewage treatment system?


WCI can provide you with a list of do`s and don`ts on request however normal domestic use should cause no problems. Too many disinfectants or antiseptics will kill off the bacteria necessary for the breakdown of sewage.

Q. My septic tank discharges directly into a ditch/watercourse. Is this illegal? What can I do about it?


If your septic tank system discharges effluent (no matter how clean) to a watercourse/ ditch you are committing an offence under Section 85 of the Water Resources Act 1991, rendering you liable on conviction and/or fine. If your septic tank is fit for purpose you can add on a secondary form of treatment such as a sewage treatment plant, reed bed or soakaway. Contact WCI now and arrange for a site inspection to discuss your treatment options

Q. What is the grey cotton wool looking material in the ditch where my system discharges?


This is sewage fungus which is a pollution indicator. It often is used as a visual sign that there is a lack of secondary treatment, that a septic tank discharges straight into a watercourse/ditch or that a sewage treatment system is failing or not performing correctly.

Failing Sewage Treatment Plant

Q. Can I still use my old brick built septic tank when I install my new reed bed/sewage treatment plant?


If your existing tank is fit for purpose (working capacity, structure and location) there is no reason why you can`t utilise it and save on costs.

Q. Do I still need a septic tank when I install a reed bed?


Yes a septic tank is used to settle out the solids from the incoming wastewater before the septic tank effluent discharges to the reed bed. If the solids are not captured in a septic tank then they will block the gravels within the bed and reduce treatment efficiency and the bedís longevity.

Q. I wish to discharge into a winterbourne watercourse. Could I use a reed bed for this?


A horizontal flow reed bed would be ideal as the discharge from a horizontal bed in the summer months is little or none, this coincides with when the watercourse flow is at its lowest, therefore reducing the environmental impact. WCI can undertake the Environment Agency discharge consent application. Contact us now on 01984 623404 to arrange a site visit.

Q. I have a manhole preceding my brick built septic tank which always blocks. It appears to have a higher level pipe above the inlet pipe which is at the bottom of the manhole. What is this and how do I solve the blockages occurring?


What you are probably describing is an interceptor trap, disconnecting chamber or a version of a Buchan trap. Such a device uses a water seal (u bend) to prevent sewer gases and vermin travelling back up the pipe work. The trap will collect solids, sludge and waste over time in the U bend and can block causing wastewater to back up. It was devised in the 19th century when it was believed that cholera was an airborne infection and often denotes the end point of the domestic propertyís sewer before it joins the main public sewer. They can however be found on private sewage treatment systems often preceding septic tanks in clay drain runs. Today pea traps and U bend on sinks, baths, showers and toilets prevent smelly gases entering the property and therefore the chamber is without a use. The best thing is to replace the whole chamber with a new manhole.

Interceptor Traps

Q. How much space do I need for a secondary treatment foul water horizontal flow reed bed system?


A typical 4 bedroom property would need a footprint of 4m x 16m. There would also need to be room for a preceding septic tank. A lesser foot print is needed when using a vertical flow reed bed which is often better suited to a steeper site. Both beds have different functions and applications which can be discussed with WCI.

Q. Will the brine/ backwash from my water softener damage my septic tank?


There are two schools of thought on this subject and a fair amount of research has been undertaken in the US. Researchers have found that brine wastes had no negative effects on the bacterial population living in the aerobic treatment tank, even when the system was loaded with twice the normal amount of brine. The additional amount of water discharged to a treatment tank during the regeneration process had no negative impact. It was also found that the water softener regeneration brine did not reduce the percolation rate of water in the absorption field of a normally operating septic system.
Some experts don`t agree with the findings above and would like to see more research done. Senior Engineering Scientists believe the sodium in the `plug flow` of brine might cause metabolic shock to the bacteria in the septic tank. This shock could cause the bacteria to be less able to digest the cellulose fibers, which then might be carried over into a septic systemís drainfield. Other engineers have also stated that there are noticeable differences between septic tanks with and without water softener brine discharges in septic tank systems including a reduced scum layer development and a less distinguishable `clear zone` that might mean solids remain suspended instead of settling in the tank.

Q. What maintenance is involved with a reed bed?


Maintenance is basic and involves weeding the bed within the first 6 months to ensure the reeds become established. Once established they will outcompete weeds. A strip around the bed should be kept mown to ensure the carryover of weed seeds is minimal. The septic tank should be emptied as advised by WCI.

Q. Why do I need a submersible pump in my system?


If the falls/ levels at your property do not allow for a gravity system then a submersible pump will be used to pump septic tank effluent to the secondary treatment system (soakaway or reed bed). The pump could also be used to pump treated effluent from a sewage treatment plant to the discharge location (watercourse, ditch or soakaway).

Q. Does a reed bed smell?


The simple answer is no. The main reason any system smells is due to an inadequate soil venting system. The soil vent system allows warm, smelly, air to vent to atmosphere via the soil stack at the head of the drain run. A poorly designed or maintained horizontal flow reed bed however can mean that effluent pools on the surface of the gravels which could cause smell. This can often be easily rectified. Contact WCI now on 01984 623404 to discuss your options.

Q. Does a reed bed attract mosquitoes?


No. Mosquitoes are attracted to stagnant water which they use as a breeding site. All water within a horizontal flow bed is below the gravels and does not stagnate. Although a vertical flow bedís surface is periodically flooded the water soaks away through the bed and the water does not stagnate.

Horizontal Flow Reed Beds

Q. I heard the Environment Agency have changed the consenting (permitting) process. How does this affect me?


`The requirement to register small domestic sewage discharges from septic tanks and small sewage treatment plants, has changed in England. The requirement to register was a result of regulations made in 2010 by the Department for Environment, Food and Rural Affairs (Defra) and the Welsh Government, as part of the implementation of the European Union Water Framework Directive. Registration was considered to provide the lightest touch approach to meet legal obligations. However, we are now undertaking a joint review with Government on the requirement to register small domestic sewage discharges in England, details of which will be announced in the next few weeks. While the review is underway, we will not require the registration of small domestic sewage discharges, including septic tanks, in England - although householders can still register if they wish`. Environment Agency Website

We still recommend that all systems are registered with the EA. If you require help registering your system please contact WCI on 01984 623404.

Q. I have a `sewage` smell in my bathroom/kitchen. How can I get rid of it?


There could be a number of causes and an easy way to detect smell is for a smoke test to be conducted. The smoke bomb is usually placed in the manhole preceding the septic tank or sewage treatment plant. The smoke will vent as the smell would, but is traceable. One possible cause is that water in the U bend or P trap has evaporated due to infrequent use and is therefore not stopping smells travelling into the room. Just flush the toilet or run water to fill the traps. Another cause can be water in the traps been removed by siphoning caused by inadequate venting which allows a vacuum to form when a large quantity of water is discharged into the drain e.g. a dishwater emptying. Check your pipe work for hairline cracks and make sure your soil vent stack is not too close to a window or door!

Q. There is a sewage smell around my system. What can I do?


There are many reasons why a system is smelly and usually it is a process of elimination to find the culprit. Such reasons include lack of soil vent stack, blocked vents, submerged pipe runs due to damage, kinks in a flexible vent pipe work in roof spaces, poor positioning of vents, dual soil vent pipes, roof water entering the system and wind direction. Contact WCI now for a survey to eliminate the problem.