Motorway Service Station Wastewater Treatment

motorway service station

It is a common issue for wastewater treatment plants at motorway service stations to be undersized or overloaded due to increasing traffic, greater numbers of visitors or expansion of the facilities. Additionally, stricter regulations on discharge licensing by the EA may warrant an upgrade to an existing treatment plant to meet new higher effluent standards. Specific issues can arise with regard to compliance with ammonia and BOD. The COD can also be extremely high due to the elevated concentrations of oil and grease in the wastewater.

A combination of the use of kitchen, cleaning and washroom facilities produce the wastewater at a motorway service station. It is characterized by highly variable flows, high ammonia content and high FOG content due to catering and food prep. There are various tried and tested methods for treating service station wastewater – the most suitable will depend on the unique requirements of the project itself. Grease management and the removal of emulsified oils must be considered before any biological treatment step. Attached growth systems such as MBBR, FBR and RBC can have an advantage over other activated sludge systems due to a longer sludge age.

In addition to consent standards, site requirements and limitations must be taken into consideration prior to supply and commission of a new treatment plant. Factors such as access, land space, gradient, the presence and location of drains, sludge management, and health and safety risks must be taken into account. 


When upgrading an existing service station treatment plant it is often a requirement to continue effluent treatment throughout the installation works. This is to allow the service station to continue to operate without disruption to business. An on-site temporary wastewater treatment plant will resolve this issue. Once the temporary plant is operational, installation of the new treatment plant and decommissioning of the old plant in part or in full can commence. To reduce capital expenditure, part of the existing equipment can be incorporated into the new treatment plant if possible. Often, a wastewater treatment plant upgrade may be required where an existing system is not complying with the current discharge limits. Specific add on modules are available to target certain parameters, such as phosphorus, nitrogen, ammonia, BOD and suspended solids. These modules can be added onto an existing wastewater treatment plant.

Motorway Service Station Wastewater Treatment Processes and Technologies

Treatment processes commonly used for motorway service station waste water include screening, buffering, SBR, DAF, settlement, and sludge treatment. Biocell Water can meet these unique challenges and provide the best available treatment technology for the unique requirements of a project on time and within budget. If you would like to know more about the solutions we provide, please get in touch. We have extensive experience working with some major motorway service station brands, including Applegreen, Circle K and the plaza group (supermacs).

Wastewater Treatment for Nursing Homes

nursing home corridor

Nursing homes and care homes produce large amounts of sewage arising from the care of patients, and from staff activities. Many nursing homes and care homes are located outside of urban areas, and are not connected to the main public sewer. They must treat their wastewater onsite by using off mains drainage solutions, septic tanks and sewage treatment plants.

Care homes typically produce higher volumes of wastewater per person than other applications. The EPA wastewater treatment manuals and the British water flows and loads document recommends that 350l/person is allowed for in the design of care home wastewater treatment solutions. To put this in perspective, a person in a domestic setting only produces 150l/day of wastewater.

Composition of Nursing Home Waste Water

Nursing home wastewater composition is different to standard wastewater. Due to the increased use of cleaning products and disinfectants for cleaning, the COD can be twice as high as normal sewage. Also, nursing home patients are typically on medication. Traces of this medication passes through the body and are then in wastewater. Many of these trace contaminants of antibiotics can have an impact on biological wastewater treatment plants. If correct consideration is not given to the concentrations of all pollutants in care home waste water, then treatment systems can fail to achieve the required design effluent standards.

A non performing wastewater treatment plant at a care home or nursing home can pose a compliance issue. All wastewater discharges from care homes are permitted. The environment agency issues a consent to discharge or a discharge permit which outlines the effluent standards that must be achieved. Failure to comply with these discharge license standards can result in fines or even closure.

Upgrading Waste Water Treatment in Nursing Homes

Typically a care home wastewater treatment plant may not achieve the BOD, COD or Ammonia [NH4N] limits. If you do not meet the limits set out in your trade effluent discharge license, then the only solution is to upgrade your wastewater treatment system.

Biocell has extensive experience in designing solutions for care home and nursing home wastewater treatment. We provide process guarantees with our solutions. This ensures that you will achieve full license compliance for your wastewater discharge. We also offer add on tertiary treatment solutions for the removal of BOD, COD and ammonia. These can be added to an existing nursing home sewage treatment plant or septic tank.

For any queries regarding a wastewater treatment system for a nursing home, discharge licence or discharge permit compliance please contact us.​

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How a non compliant septic tank can affect the sale of your UK home

Non-Compliant Septic Tank

A non-compliant septic tank can seriously devalue the sale of your home. But what makes a septic system non compliant? You will find the answer in the General Binding Rules, which we have summarised here in an earlier blog post.

Why is my septic tank non compliant?

A septic system can be non-compliant for a wide variety of reasons. A leaking tank, poor effluent quality or a tank discharging directly to a soakaway or stream are common causes for non compliance. (The latter being the most recent regulation in the general binding rules to be enforced as of January 2020.)

Septic Tank Inspection

How do I know if my septic system is non compliant? If you are selling your house, an inspector will examine your septic tank. If your septic tank fails the inspection it will be flagged to potential buyers. A non compliant septic tank can devalue the sale of a house up to as much as £10,000.

Invest in Compliance

The quickest and most cost effective way to deal with a non compliant septic tank is to replace it with a certified sewage treatment plant. Especially if the existing tank is discharging to a soakaway or watercourse.

Investing in a certified system will always cost less than what it would not to. A compliant septic tank is always a plus point for potential buyers. From as little as £1249 an issue of non compliance can be addressed with the fully certified Biocell BioClean domestic sewage treatment plant. The BioClean is the most affordable home sewage treatment plant on the UK market. Furthermore, it is steel reinforced and does not require concrete backfill on most sites saving on costly installation works.

For issues of non-compliance relating to direct discharge, the ClearFox Nature is an ideal solution. With effective treatment levels of 98%, the ClearFox Nature can legally discharge direct to a stream or watercourse. Although pricier than other systems, the ClearFox can eliminate the need to install a soakaway – saving on costly and time consuming installation works.  And remember, the money earned back on the sale of your home could well exceed the cost of addressing a non compliant septic tank.

Eco Friendly and Sustainable Home Sewage Treatment

eco friendly sewage treatment

Now that pollution is at a critical level and has become a serious worldwide concern, we are becoming increasingly aware of how important it is to choose eco friendly and sustainable options as often as possible. We are less inclined to use single use plastics, are more likely to recycle, eat clean and choose solar or wind powered electricity options where possible. And for some of us, we now thankfully have the option to choose eco friendly and sustainable home sewage treatment options.

In a sense, the concept of modern sewage treatment is already an eco friendly process. It involves reducing harmful compounds in sewage water that would otherwise cause damage to human health and natural eco systems. However, not all modern home sewage treatment plants can claim to be both eco friendly and sustainable.

Electricity and Sewage Treatment

In almost all cases, modern home sewage treatment plants use electricity in order to operate. At a very basic level, the concept of modern sewage treatment involves increasing the levels of oxygen in the sewage water in order to accelerate the treatment process. For this to happen, most sewage treatment plants use air blowers to introduce the extra oxygen into the sewage. Unfortunately, the use of electricity to power the air blowers is not a sustainable method of home sewage treatment, especially if the air blowers run 24/7.

An Eco Friendly Home Sewage Treatment Plant

An eco friendly home sewage treatment plant should only use electricity when necessary. The main electrical components of a modern sewage treatment plant are the air blowers. Instead of running 24/7, the air blowers should only activate whenever raw sewage enters the system and run for the appropriate length of time it takes to clean the sewage. Not only does this benefit the environment but also results in cost savings for the end user.

An example such of an eco friendly sewage treatment plant is the Biocell QuickOne+, costing as little as €0.10/£0.08 per day. The QuickOne+ oxygenates raw sewage for exactly the length of time required to achieve the appropriate treatment levels.

A Sustainable Home Sewage Treatment Plant

According to Google, the definition of sustainability is avoidance of the depletion of natural resources in order to maintain an ecological balance

In order to fit this definition, a sustainable home sewage treatment system would have to operate without electricity. It may be difficult to imagine that a sewage treatment plant could achieve the necessary treatment levels without electricity but it is possible. An example of such a sustainable home sewage treatment plant is the ClearFox Nature. This clever system uses natural aeration to oxygenate the incoming wastewater without electricity.


Not only does it require zero electricity to run, it is also capable of treating sewage to such high standards that it is legally acceptable to direct the discharge to a watercourse.

See the video below for an explanation of how the ClearFox Nature operates without electricity to earn its status as a sustainable home sewage treatment system.

Sewage Treatment and Noise Pollution

The key behind an environmentally friendly product is the way in which it blends into and fits within its surroundings. This means reducing waste, but it also means reducing sound. It’s hard to predict the impacts that a loud home sewage treatment system would have on the wildlife near your home. However, it’s fair to assume that it wouldn’t be positive.

An eco friendly and sustainable sewage treatment plant produces little to no noise pollution. Motors and mechanical parts inevitably produce a certain level of noise so it’s important that such components only operate when necessary, like the QuickOne+.


On the other hand, the ClearFox Nature as mentioned above, operates without motors or electricity and uses natural ventilation to treat the incoming sewage, resulting in zero noise pollution. This means that the impact on local wildlife is is kept to a minimum and stays in line with the goal of sustainable sewage treatment.

For a free quotation on eco-friendly and sustainable home sewage treatment systems contact Biocell Water today.


Pump Station Refurbishment

commercial wastewater pumping station

A pump station refurbishment is required

when existing equipment needs to be upgraded and repair or maintenance is no longer a suitable option. This can be due to a change in requirements or failure of the existing equipment.

Depending on the requirements, a pump station upgrade may involve replacing a single pump, multiple pumps or complete replacement of all pumps and equipment, control panels and pump house.

A pump station refurbishment is advantageous

in many ways, for example;

  • reducing maintenance costs
  • reducing running costs
  • improving pumping efficiency
  • improving health and safety

The goal of a pump station refurbishment is to increase performance, reduce energy consumption and to continue operating reliably on a long term basis.

The process of refurbishing a pump station

varies depending on the location and condition of the existing pump station and the site requirements. Typically, the process will involve working in liaison with civil contractors and may require the implementation of traffic control systems and/or the installation of a temporary sewerage bypass system.

The basic refurbishment process is as follows;

  • Structural assessment of the existing pumping station
  • Design proposal for refurbishments
  • Dismantle/deconstruction of the existing pump station and/or equipment
  • Installation of new equipment and commissioning of the upgraded pump station

A failed pump station

can occur for various reasons. A failing pump station will often need to be emptied regularly and can result in sewage overflows. Aside from the obvious contributing factors such as old or faulty equipment or lack of close monitoring and maintenance, there are other possible causes for break down. Due to the fact that pump stations are large integrated systems, the failure of any individual component will effect the whole system.

Blockages can occur in the pipework, the valves or the pumps and can be the result of an under-specification of the system or a build up of fats and grease.

Debris can get caught around the floats and result in a failure of the level control system.

Damaged cables or broken seals can result in water getting into the motor of the pump and causing pump station failure.

Unmaintained and corroded pipework or damaged valves can result in pump station failure.

For all of the above reasons and more, it is essential to keep a pump station closely monitored and frequently maintained for optimal performance and long term operation.

After refurbishment, a pump station

should be serviced at least every 12 months. High-use pump stations should be inspected even more regularly.

This ensures that any potential failures can be identified and serviced before occurring.

A pump station upgrade may include the retrofitting of a telemetry system inside the control panel.

This alerts the appropriate people via text message of any issues inside the pump station such as high levels in the tank, loss of power or a potential blockage due to high pump running times.

In this way, problems or failures can be rectified quickly and in some cases even avoided altogether.

Common Septic Tank Problems

looking inside septic tank

A septic tank problem is something that most people have to deal with at a certain point. As experts in the industry, we come across problems with septic tanks quite often so here we list the most common ones and how to solve them.

A bad smell coming from the septic tank

Bad smells are one of the most common septic tank problems. Remember, that it’s normal for there to be a weak bad smell in and around the septic tank. The smell of sewage is one that most people can recognize. If you are finding an overpowering bad smell of sewage then there is a problem! Most likely, the septic tank needs to be emptied. A septic tank should be emptied regularly, usually every 18 months, depending on usage.

Another possible cause of bad smells from a septic tank is poor ventilation. There should be a vent at the septic tank, or a soil vent stack at the house. Make sure to check the soil vent stacks regularly for blockages. The ends of percolation trenches should also be vented. 

A leaking septic tank

Another common septic tank problem is a leaking tank which results in wet or boggy patches in and around the location of the tank. There may be a number of reasons for a septic tank to leak. If the tank is cracked or damaged it may need to be replaced – cracks or damage can be the result of poor installation. To spot any damage, you will need to have the tank emptied so that cracks are visible and/or you can spot any water seeping through.

Another reason for a leaking septic tank is if it is not properly sealed. There are various parts of a septic tank that need to be sealed. In two part concrete tanks, leaks are most commonly found where the two parts meet and are sealed. Another area where leaks can occur, especially in older septic tanks, is at the inlet and outlet pipes. A rubber gasket can help to seal the tank at the entry and exit openings.

A blocked septic tank

This is another common septic tank problem. In this case, a blocked septic tank is often the result of what has been flushed down the toilet. Anything that isn’t biodegradable will not be broken down inside the septic tank and will simply stay there until the tank is emptied. Most often, the blockage is not inside the tank but rather in the pipes or even the percolation area.

The best course of action here is to contact a drain cleaning company to have the pipes jetted.

A flooded septic tank

Another common septic tank problem is a flooded tank. This can happen if the tank has not been emptied in a long time, is damaged or overloaded. Wet and rainy weather can flood a septic tank if storm water runoff is directed towards it or the pipes leading towards it – only wastewater generated within the house should be directed to a septic tank. A blocked percolation area can also result in the backflow of water through the pipes and back into the septic tank.

Again, the best course of action is to have the tank emptied and observed for any signs of leakage or back flow into the tank.

5 tips to solve septic tank problems

  1. Hire a professional to empty the septic tank.
  2. Observe the empty septic tank for signs of damage, cracks or ground water leaking into the tank.
  3. Observe the empty tank for water flowing back into the tank from the percolation area.
  4. Check for signs of leaks at seals and covers.
  5. Hire a professional to check the pipes for blockages or signs of damage.

Remember safety first! This should only be considered a guideline, it is always best to seek the help of a professional! The best way to avoid septic tank problems is regular maintenance and proper usage.

What not to flush down the toilet if you have a septic tank!

Unclogging septic system. Cleaning and unblocking drain full of disposable wipes and other non biodegradable items.

If you have a new septic tank, or have bought a new home with its own sewage treatment plant, we’ve put together this quick guide on what not to flush down the toilet to keep your new system in top working order!

Stating the obvious…

Firstly, it’s important to understand what your new septic tank is for: sewage treatment. Whatever you flush down the toilet goes to the septic tank for treatment. So anything that isn’t sewage isn’t treatable and will accumulate inside the tank, interfere with the microbes, clog pipes or get stuck in the equipment.

Can babywipes be flushed?

Do not flush babywipes down the toilet unless they are biodegradable, the packaging will clearly state if they are. The risk to a sewage system is wipes getting caught in a pump impeller and causing it to fail. They also pose a risk of severe blockages to plumbing and pipework. The reason for this is very well explained by Kian Hennessy in his 2014 Young Scientist exhibit:

Kian Hennessy explains why not to flush wet wipes down the toilet.

What happens to your septic tank when you flush a wet wipe down the toilet

Flushing a wet wipe or similar down the toilet firstly slows the flow of water and waste through the pipework. Once inside the pipework it might get stuck and cause a blockage. Otherwise, it will eventually enter the septic tank where it will float about, never breaking down and taking up valuable space until it is time for desludging.

The same can be said for flushing tampons, sanitary towels, condoms or nappies down the toilet. It simply isn’t worth the risk.

Instead of flushing bulky, non biodegradable items down the toilet – bag and bin them instead. It is a little less convenient but it’s far, far less expensive than the cost of a fixing sewage back up or a replacing a sewage pump.

Can bleach be flushed?

Go easy on the bleach. A domestic septic system can deal with small, dilute amounts of bleach but using too much will harm the microorganisms inside the system that are responsible for cleaning the sewage. Wiping out these microorganisms with bleach defeats the purpose of having a sewage treatment plant, so try not to be too heavy handed with it.

Can used cooking oil be flushed?

Large quantities of used cooking oil should not be flushed down the toilet (or rinsed down the sink). Fats clog pipework, cause blockages and create sewage backups if not properly disposed of. A septic tank can cope with small amounts of grease diluted in soapy dishwater but dumping the contents of the deep fat fryer down the drain will cause problems. wikiHow have produced an excellent article on how to dispose of cooking oil if you’d like to know more.

What can I flush down the toilet if I don’t have a septic tank?

For those of us without a septic tank, i.e. connected to mains sewerage – the same applies. Everything we flush down the toilet ends up in the municipal sewage works and despite operating on a much larger scale, the same issues arise. Problems with sewerage works are an unpleasant situation for everyone involved and are largely avoidable if we simply pay a little more attention to what we flush down the toilet!

Tertiary Treatment Modules Guide | Alternatives | Comparison

tertiary filterpod sewage treatment

In this week’s blog post we cover the topic of tertiary treatment modules and compare popular units such as cocofilters, peat filter modules and filterpods. We will discuss what they are, what they do and why they might be specified in a site characterisation report by a site suitability assessor.

What is a tertiary treatment module?

A tertiary treatment module is a wastewater treatment unit that cleans effluent to higher levels after secondary treatment. Secondary treated effluent from a sewage system either flows by gravity or is pumped to the treatment module. Inside, it filters through a medium before it discharges to ground for disposal.

There are many modules on the market but the type of medium and the size and structure of the unit will differ. The medium can consist of organic material such as peat or coconut shells. Alternatively, it can be made up of inorganic material.

How does a tertiary treatment unit work?

The basic principle of the tertiary treatment unit is biofiltration and adsorption which occurs throughout the media inside the module. The porous nature of the media adsorps pollutants in the wastewater. At the same time, microorganisms colonise the high surface area of the media and breakdown the remaining waste components. This results in a high level of treatment before the final effluent is discharged to ground.

What options are available for tertiary treatment modules?

Coco filters, peat filter modules and filterpods are some examples of tertiary treatment modules that are available on the market today.

What is a cocofilter?

As the name suggests, a coco filter uses derivatives of coconut shell as the filtration media. This is an organic material with a high capacity to adsorb (retain) pollutants.

Eventually, this type of media will become saturated with pollutants and need complete replacement. The length of time this takes depends on the manufacturer’s specifications. Generally speaking, every 5-10 years is the average.

Advantages: Medium cost. Easy to install.

Disadvantages: Moderate to high operation and maintenance costs due to complete replacement media. Risk of clogging.

What is a peat filter?

Peat filter modules contain pre-compacted peat or peat fiber as media. This is a special form of peat with a very specific moisture content and degree of decomposition. It provides an ideal environment for supporting the microorganisms’ biological treatment of the sewage. Like coconut, peat will settle and decompose over time. Replenishing or topping up the peat on yearly basis can help combat problems with odor. Eventually the peat media will need complete replacement, usually every 8-12 years.

Advantages: Low to medium cost. Easy to install.

Disadvantages: Moderate to high operation and maintenance costs due to complete replacement media. Risk of clogging.

What is a filterpod?

A filterpod is a tertiary treatment module which uses a synthetic medium in the form of RDX filter media. This has been specifically engineered for the purpose of wastewater treatment. The matrix of the RDX filter promotes the growth of aerobic bacteria and provides rapid adsorption of wastewater. Air can also circulate freely through the media. The top layer of the filter media needs annual replacement, but the cost is generally 25-30% less than replacing media of other forms.

According to the EPA Code of PracticeWastewater Treatment and Disposal Systems Serving Single Houses (p.e < 10), any tertiary treatment system selected for treating secondary effluent must conform to prEN 12566-7, this is easily checked with the supplier/manufacturer.

Advantages: Low cost. Easy to install. Can be used to replace percolation area.

Disadvantages: Top layer of media needs to be replaced intermittently.

Advantages of tertiary treatment units

By comparison to alternative forms of advanced treatment such as sand polishing filters, tertiary treatment modules are very straightforward to install. They do not have to be constructed on site as the unit is already fully equipped by the supplier. Additionally, they have a smaller footprint and are suitable for installation above or below ground. This means that installation is quicker, easier and less costly than other forms of tertiary treatment.

Why do I need a tertiary treatment module?

An engineer or site assessor specifies a tertiary treatment system based on a number of factors including the site conditions, the level of secondary treatment and the requirements of the receiving waters. The sensitivity of the receiving waters and the permeability of the soil depend largely on the site location. The loading rates will dictate the level of tertiary treatment required.

If you do need a tertiary treatment module, bear in mind that it does not have to be the exact model specified in the report. You may choose a suitable alternative that meets the treatment standards set out in the report. The treatment efficacy of any unit on the market today is easily checked with the supplier/manufacturer.

Wastewater Treatment for a Fruit and Vegetable Processing Plant

fruit vegetable processing wastewater

Fruit and vegetable processing plants generate large volumes of high strength wastewater that cannot be discharged without pretreatment.

Fruit and vegetable process plant wastewater typically contains discarded fruits and vegetables, soil particles, fruit and veg pulp and fibers, cleaning agents, blanching agents, salt and residues of pesticide. In addition to that, processing onions and ready made meals produces foul smelling wastewater. This unique and complex effluent requires specific and effective treatment. In this article we discuss some of the processes and technologies a wastewater treatment plant uses in order to produce cleaner fruit and vegetable process effluent.

Good practice in waste management reduces volumes of wastewater in a fruit and vegetable process plant by up to 95%.  Such pollution control measures include dry cleaning and peeling of raw materials and recirculation of process wastewaters. This can significantly reduce the cost of wastewater treatment for a fruit and vegetable process plant and benefit the environment too.

Selecting the most suitable treatment for fruit and vegetable process wastewater depends on three main factors:

  • the characteristics of the effluent
  • the site conditions
  • the economic viability of the proposed treatment plant

Therefore the configuration of a wastewater treatment plant will be specific to the unique requirements of the fruit and vegetable process plant.

It is important that the relevant analyses and surveys are carried out on the effluent in order to design the most suitable treatment plant. These tests will often include BOD, pH, temperature, suspended solids, volatile solids, settleable solids, and FOG. Often, the wastewater treatment specialists in charge of the job will design and implement a pilot scale plant to determine the best course of treatment for the fruit and vegetable process effluent. Adjustments can be made until the pilot scale plant is meeting the target effluent standards, at which point the full scale treatment plant is ready to commission and install.

Generally speaking, the most common treatment processes for food process effluent  involve screening, pH adjustment and biological treatment. Production in a fruit and vegetable processing plant is often seasonal and it is for this reason that the wastewater treatment system needs to be robust and flexible. The basic pattern for treating wastewater of the seasonal kind is regulation, aeration, and settling.

Pretreatment of Fruit and Vegetable Process Effluent

Pretreatment is a term that covers a wide range of different processes in wastewater treatment. Some common forms of pretreatment of fruit and vegetable process effluent include flow equalization, screening, gravity separation of floatables and solids, dissolved air flotation (DAF), chemical treatment to supplement gravity separation or DAF, and biological treatment.

Flow equalization and neutralization reduce hydraulic loading and correct pH. The equipment includes buffer tanks, pumping equipment and air blowers which serve to mix the effluent, balance fluctuations in the waste stream and adjust the pH levels. Buffer tanks uniformly feed the flow to the treatment facilities or store the effluent for recycling/reuse elsewhere in the fruit and vegetable processing plant.

Screening removes larger solids and particles from the effluent by filtration through a mesh. In terms of fruit and vegetable process effluent, vibrating and rotary screens are most effective. Screening lowers suspended solids, settleable solids and reduces BOD discharge. It prevents clogging of municipal sewers and prevents damage to onsite treatment equipment. Screening also makes the downstream treatment processes more efficient. Currently, the most popular screens for fruit and vegetable process wastewater are vibrating/oscillating screens and rotary drum screens. Screening is the most inexpensive form of pretreatment.

Another common method of pretreatment of fruit and vegetable process effluent is  separation of the floatables and settleable solids. This is usually by gravity or by air flotation. Certain waste streams may require the addition of chemical additives such as Al2(SO4)3, FeSOand FeCl3 to enhance the separation during DAF.  This can reduce the BOD concentrations in the wastewater significantly enough to finally discharge to a municipal plant.

Biological Treatment of Fruit and Vegetable Process Wastewater

The use of biological secondary treatment is often necessary in order to meet local wastewater effluent standards. For fruit and vegetable process effluent, there are several different systems that can provide secondary treatment and the choice is largely dependent on the characteristics of the waste stream. Often, a combination of techniques will provide the best result. Some of these secondary processes include anaerobic lagoons, aerobic lagoons, faculative ponds, aerated lagoons, trickling filters, activated sludge and rotating biological contactors. As already mentioned, the choice will depend entirely on the characteristics of the effluent, the site conditions and the economic viability of the proposed treatment plant and associated technologies.

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General Binding Rules and 2020 Septic Tank Regulations Explained

A Breakdown of the General Binding Rules for Small Sewage Discharges

In this blog we aim to break down the General Binding Rules for small sewage discharges using a systematic approach. The rules differ depending on whether the sewage system you have or plan to install discharges to ground or discharges to surface water. The full list of rules is available here at the website but not all of them will apply to you. You will need to know where your discharge point is located (to ground/to surface water) in order to find out which rules apply to you. You will also need to know if you are operating a septic tank or a sewage treatment plant and whether or not you have a drainage field installed. If you already have an idea of what the rules mean and why they exist you can skip ahead to the section on rules for Discharges to Ground or to the rules for Discharges to Surface Water. In the last section we cover the General Binding Rules that apply to all Small Sewage Discharges.

What is meant by the General Binding Rules for Small Sewage Discharges?

The General Binding Rules regulate small sewage discharges and apply to anyone that operates a septic tank or small sewage treatment plant in England. Under these regulations, anyone that has or plans to install a septic tank or small sewage treatment plant must follow the general binding rules as a minimum. Once you comply with the General Binding Rules, you do not require a permit. Permitting allows the Environment Agency to assess the discharge to ensure that it won’t cause pollution, and to specify additional requirements beyond the general binding rules if necessary. All small sewage discharges in designated sensitive areas (or those that cannot meet the General Binding Rules) are required to have a permit.

When do I need a permit for a small sewage discharge?

The whole purpose of the General Binding Rules is to protect water resources from pollution caused by small sewage discharges. If you already have a small sewage discharge without a permit, you are essentially agreeing to be bound by the General Binding Rules. Where it is not possible to comply fully with the General Binding Rules, the Environment Agency can issue a permit. Bear in mind that the Environment Agency will only grant a permit for a small sewage discharge if there is no evidence of pollution or if the risk of pollution is acceptable. If there is evidence of pollution or a significant risk of pollution, you must replace or upgrade your sewage system in order to comply with the General Binding Rules or meet the conditions of a permit. You will find an application form for a permit here on the website. The form you need to fill in depends on where you discharge the sewage to (groundwater/surface water) and how much sewage you discharge (based on the largest amount you are likely to discharge). Read on to find out more.

The following General Binding Rules apply specifically to small sewage discharges to ground:

  • The discharge must be 2 cubic metres or less per day in volume.
    If you are unsure about the volume of discharge from your property, you can download a daily discharge volume calculator tool here on the website. A permit is required to discharge any more than 2,000l of treated sewage per day to ground.
  • The sewage must receive treatment from a septic tank and infiltration system or a sewage treatment plant and infiltration system.
    If you do not have an infiltration system in place you must arrange for one to be installed. An infiltration system is an area of ground set out with perforated pipework at specific spacing and elevation to distribute the effluent for treatment within the soil underneath.
  • The discharge must not be within a groundwater Source Protection Zone 1 [SPZ1] or within 50 metres from any well, spring or borehole that is used to supply water for domestic or food production purposes.
    You must apply for a permit if this is the case. The minimum size for a groundwater SPZ1 for a drinking water supply is a 50m radius from the source.  No matter how large a groundwater SPZ1 is, any small sewage discharge discharging to ground within it will require a permit. You can contact the Environment Agency to find out if you are within an SPZ1.
  • New discharges* must not be in, or within 50 metres of, a Special Area of Conservation (SAC), Special Protection Area (SPA), Ramsar site, or biological Site of Special Scientific Interest (SSSI), and must not be in an Ancient Woodland.
    As these are sensitive areas for wildlife and habitats you must apply for a permit to discharge here. You can contact the Environment Agency to find out if you are within any of these areas.

*New discharges are considered to be those started on or after 1 January 2015.

The following General Binding Rules apply specifically to small sewage discharges to surface water:

  • The discharge must be 5 cubic metres or less per day in volume.
    If you are unsure about the volume of discharge from your property, you can download a daily discharge volume calculator tool for small sewage discharges here on the website. A permit is required to discharge any more than 5,000l of treated sewage per day to surface water. 
  • The sewage must receive treatment from a sewage treatment plant.
    This means that a septic tank discharging direct to surface water (brook/river/streams/ditches etc.) is no longer allowed and must be replaced with or upgraded to a sewage treatment plant. The Government have given operators until 1 January 2020 to arrange this. We covered the difference between a septic tank and sewage treatment plant in an earlier blog post.
  • For discharges in tidal waters, the discharge outlet must be below the mean spring low water mark.
    This means the discharge point must be at a height less than the average height obtained by the two successive low waters during the same period.
  • New discharges must not be in or within: 500 metres of a Special Area of Conservation (SAC), Special Protection Area (SPA), Ramsar site, biological Site of
    Special Scientific Interest (SSSI), freshwater pearl mussel population, designated bathing water, or protected shellfish water; 200 metres of an aquatic local nature reserve; 50 metres of a chalk river or aquatic local wildlife site.
    As these are sensitive areas for wildlife and habitats you must apply for a permit to discharge here. You can contact the Environment Agency to find out if you are within any of these areas.
  • New discharges must be made to a watercourse that normally has flow throughout the year.
    This means that the discharge cannot be to surface water that does not contain flowing water throughout the course of the year (unless there is an unusually long period of dry weather or a drought). Ditches are no longer acceptable to discharge to.
  • For new discharges, any partial drainage field must be installed within 10 metres of the bank side of the watercourse.
    A partial drainage field is a seasonal system that works differently in the summer and winter which means that you’re discharging both to groundwater and to surface water, depending on the seasonal ground conditions. The Environment Agency considers 10m to be close enough to the water course to be defined as a discharge to surface waters. So this rule is essentially in place to maintain a distinction between discharging to ground and discharging to surface water.
  • New discharges must not be made to an enclosed lake or pond.
    Unlike a watercourse with flow (rivers and streams), lakes and pond have a limited supply of oxygen. When the oxygen in a lake or pond is used up by the bacteria in the discharge (even if it treated to good standards), pollution occurs.

The rest of the General Binding Rules apply to all small sewage discharges and are as follows:

  • The sewage must only be domestic.
    This is typically waste from toilets, sinks and drains in a home or small business like a nursing home, guest house or pub provided that the activities remain in proportion to the domestic scale.
  • The discharge must not cause pollution of surface water or groundwater.
    This is the all-encompassing rule and the purpose of the General Binding Rules.

  • All works and equipment used for the treatment of sewage effluent and its discharge must comply with the relevant design and manufacturing standards  i.e. the British Standard that was in force at the time of the installation, and guidance issued by the appropriate authority on the capacity and installation of the equipment.

    The works must comply with the Building Regulations, H2, 2010 and the equipment must comply with the relevant BS EN 12566 series of standards for Small Wastewater Treatment Systems for up to 50 PT. A reputable wastewater treatment company will confirm that their equipment is certified to the relevant standards and the capacity of the system is suitable for the discharge. If you are employing a builder to carry out installation works, it is their responsibility for making sure that it complies with the building regulations. However, if an inspector finds that the work does not comply with the regulations then it is up to the owner of the property to address it. How to avoid this? Use a reputable builder.

  • The system must be installed and operated in accordance with the manufacturer’s specification.
    You risk losing your warranty if you do not follow the installation and operation guidelines provided by the manufacturer of the sewage system.
  • Maintenance must be undertaken by someone who is competent.
    Self explanatory – do not attempt to do this yourself, unless you are a trained and certified maintenance technician/engineer. Otherwise, you risk losing your warranty. Contact the manufacturer to arrange appropriate maintenance. A new sewage treatment plant may include a maintenance package in the price.
  • Waste sludge from the system must be safely disposed of by an authorised person.
    British Water recommends that “Non-mains sewage treatment system owners should enter into a maintenance contract with a competent operator which uses suitably qualified personnel who have passed the British Water Maintenance and Servicing Training Scheme.” You can download the British Water guide to the Desludging of Small Wastewater Treatment systems here on their website.
  • If a property is sold, the operator must give the new operator a written notice stating that a small sewage discharge is being carried out, and giving a description of the waste water system and its maintenance requirements.
    If your sewage system does not meet the General Binding Rules you must remedy it at your own expense. Otherwise, you can expect the value of your property to decrease significantly or be much slower to sell – it is unlikely that a buyer would want to take on this extra expense.
  • The operator must ensure the system is appropriately decommissioned where it ceases to be in operation so that there is no risk of pollutants or polluting matter entering groundwater, inland fresh waters or coastal waters.
    To decommission a disused septic tank:

    • Locate the septic tank and uncover the top of the tank (generally 30 – 60 cms below ground level). Do not enter the tank.
    • Have the septic tank wastewater (liquid and sludge) pumped out completely by a licensed hauler.  It is important to pump the wastewater, as it contains bacteria and viruses that could make you or your family ill. Keep the pumping receipt as it acts as proof-of-pumping.
    • Fill in the septic tank completely with sand, gravel or soil and put the access lid(s) back in place, or demolish the tank. Ref:
  • New discharges must not be within 30 metres of a public foul sewer.
    If you can access a sewer, access a sewer.
  • For new discharges, the operator must ensure that the necessary planning and building control approvals for the treatment system are in place.
    Contact the Environment Agency before installing a new system or making changes to an existing system to check if a permit is required. Before carrying out any installations, contact your local planning authority to check if it requires planning permission. We already discussed Building Control Approvals here.

That concludes our explanation of the General Binding Rules for small sewage discharges.

Remember, do not make any changes to an existing sewage system or begin a new installation without first consulting with the Environment Agency regarding a permit; they are there to help. Equally, do not commence any work without first checking if planning permission is required from your local council or planning authority. To help you, we have included a list of useful links below regarding the General Binding Rules for septic tanks and small sewage treatment plants in England:

General Binding Rules for Small Sewage Discharges []
FAQs on the General Binding Rules for Small Sewage Discharges []
Guidance on meeting the General Binding Rules for Small Sewage Discharges []
Information about Building Regulations and Planning Permission []
Building Regulations for Drainage and Waste Disposal (H2) []
Permit Applications for Small Sewage Dischares []
Guidance on Permit Compliance for Small Sewage Discharges []
British Water Codes of Practice relating to Small Wastewater Treatment Systems []