• AdBlue Tanks
    • How should I store AdBlue™?

      As AdBlue™ is very sensitive to contamination, it is important that it is stored in a containment system which can protect it from contamination threats, and which can maintain the AdBlue™ at an optimal condition.

      The de-ionised elements of AdBlue™ can draw ions from the materials in which it is stored. This can change the chemical composition of the AdBlue™ and causes salts to form which in turn clog the ceramic head on the SCR.

      A common cause of premature SCR failures is the incorrect material selection in AdBlue™ Storage. Inert materials should always be used to handle AdBlue™.

      Harlequin AdBlue™ storage and dispensing tanks have been designed specifically for the safe and secure storage of AdBlue™. In addition, all AdBlue™ dispensing equipment has been selected in order to protect both the AdBlue™ solution and the equipment itself.

    • What Is AdBlue™?

      AdBlue™ is a trade name for AUS32 (Aqueous Urea Solution 32.5%). It is injected into the exhaust gases of modern diesel engines as a post combustion process. Its purpose is to reduce the percentage of harmful NOx (Nitrous Oxides) present in a vehicle’s emissions.

      The reaction takes place in a special piece of equipment called a SCR. The requirements to reduce vehicles harmful emissions (pollutants) are specified in European legislation, namely Euro 4, 5 and 6.

      In order to reach the reduced levels of pollutants as defined within current and future European legislation, vehicle manufacturers need to call on one of two types of technology: either SCR (Selective Catalytic Reduction) or EGR (Exhaust Gas Recirculation).

    • What Is A SCR?

      SCR stands for Selective Catalytic Reduction. Vehicles which are equipped with a SCR will carry an AdBlue™ storage tank in addition to the standard fuel tank. AdBlue™ is transferred from the storage tank and injected under pressure into the exhaust gases where a series of chemical reactions take place.

    • What Regulations Should I Be Aware Of?

      ISO 22241-1 Standard for AUS32
      ISO22241-2 Standard for Quality Testing of AdBlue™
      ISO 22241-3 Standard for Handling, Transportation and Storage of AdBlue™

  • Diesel Tanks
  • Fuel Storage Tanks: Bunded Oil Tanks
    • How close to a building can I place my Heating Oil Tank?

      Oil Tanks with a capacity not greater than 3500 litres should not be fitted any closer than 1.8 metres to non-fire rated (30 mins. minimum) walls or eaves.

      Where these clearances cannot be achieved, the protection measures noted in British Standard BS 5410: Part 1: 1997 must be provided by means of a 30 minute fire-resistant wall which extends at least 300mm above and beyond the ends of the tank.

      It will be necessary to protect exposed eaves forming part of a roof within 1.8 metres of the top of an oil storage tank to provide a 30 minute resistance to fire. Cladding can be applied to the eaves in order to prevent fire spreading to the roof.

      If the tank capacity is greater than 3500 litres or you require further advice, please contact OFTEC.

    • How close to a flu outlet can I place my Heating Oil Tank?

      Oil Storage Tanks with a capacity of less than 3500 litres should not be placed within 1.8 metres of a flu outlet.

      Where these clearances cannot be achieved, the protection measures noted in British Standard BS 5410: Part 1: 1997 must be provided by means of a 30 minute fire-resistant wall which extends at least 300mm above and beyond the ends of the tank.

      For oil tanks with a capacity over 3500 litres or advice on constructing a fire resistant barrier, please contact OFTEC.

    • How secure are Heating Oil Tanks manufactured by Harlequin?

      Harlequin oil tanks are the most secure tanks you will find in the market. All our bunded oil tanks are lockable at both the fill and inspection points. We also provide a range of added security accessories.

    • How should I maintain my Heating Oil Storage Tank?

      Oil tanks should be maintained yearly, by an OFTEC certified tank installer. You can ask your tank installer to provide a tank check as part of your boiler service.

    • What is a Bunded Tank?

      A bunded heating oil tank simply consists of a tank within a tank. The fuel is stored in the inner tank and the outer tank acts as a failsafe so that in the event of a spillage, excess fuel will collect in the outer tank – thus averting a pollution incident.

      Bunded heating oil tanks have been proven to significantly reduce the risk of pollution at oil storage installations. They are a requirement at commercial, industrial, institutional and commercial premises; all installations in the Channel Islands; and, at most domestic installations in the United Kingdom and Republic of Ireland.

      Single skin tanks on the other hand, consist of only one shell or skin. This means that in the event of a tank split, valuable heating oil will be lost and the surrounding environment will be polluted by the heating oil contained within it.

    • What is the difference between a Top Outlet and a Bottom Outlet Tank?

      Top outlet bunded oil tanks are quite simply oil tanks which have the outlet to the burner placed at the top, rather than the bottom of the tank. Oil is then drawn out, as opposed to being gravity fed through the outlet at the bottom. All Harlequin bunded oil tank models can be provided as either top outlet (ITT) or bottom outlet (ITE) tanks.

      Top outlet oil tanks are suitable for use with most pressure jet burners – we recommend installing a Tiger Loop de-aerator, to eliminate the need for a return line to the tank. Pressure jet burners are fitted to most oil boilers sold today in the British Isles.

      Top Outlet Bunded Oil Tanks are not compatible with vapourising (or wick) burners, fitted to some oil fired stoves. At such installations, a bottom outlet bunded oil tank should be fitted or else an oil lift device should be incorporated within the oil supply line.

      If you are in any doubt as to the compatibility of top outlet or bottom outlet bunded tanks, consult the appliance manufacturer or OFTEC.

    • What is the maximum temperature of liquids which can be stored in a Heating Oil Tank?

      55 Degrees Celsius is the maximum temperature for liquids stored in oil tanks manufactured by Harlequin.

    • What should I do if my Heating Oil Tank has split?

      If you have noticed a split or a point of leakage on your oil tank you must act quickly, as an oil spill can severely damage the surrounding environment and can lead to expensive clean-up costs.

      Contact your nearest approved oil tank technician to arrange an emergency call-out. You can also contact OFTEC for advice in such situations.

    • What should I do if water gets into my Heating Oil Tank?

      Water will form in any oil storage tank. It is perfectly normal and occurs as a result of the tank warming up during the day and then cooling at night. In single skin oil tanks it will collect in the base of the tank; in bunded oil tanks it may additionally collect between the inner and outer tanks.

      All bunded oil tanks should be inspected annually for the presence of water either inside the oil tank or in the case of bunded oil tanks, between the inner and outer tank. Failure to remove any condensation may result in fuel contamination and irreparable product damage.

      Condensation can be removed by most oil tank installers, technicians and most fuel distributors. We can recommend an OFTEC-certified tank installer for you as we work very closely with a number of installers. This allows us to recommend only the best and most reliable installer to our customers.

    • What should I know before buying a Bunded Heating Oil Tank?

      Before purchasing an oil tank, it is worth consulting The Oil Firing Technical Association (OFTEC) for relevant information surrounding the storage of heating oil.

      Not all domestic heating oil tanks are the same. Some are made from steel, some from plastic, some are thicker than others, some are single skin, and some are bunded.

      Firstly, you need to know if you want a steel tank or a plastic oil storage tank. Harlequin manufacture rotationally-moulded plastic oil storage tanks as they are not susceptible to the same levels of corrosion as steel tanks. They are also lighter and easier to transport, not to mention being more economical.

      Harlequin oil tanks are made from medium density polyethylene (MDPE). Materials and components used in the manufacture of Harlequin Oil Tanks are resistant to the potentially damaging effects of the liquids they are designed to contain. MDPE displays excellent chemical and impact resistance qualities. All Harlequin Oil Tanks are manufactured only from premium grade, virgin materials.

      You also need to consider whether you wish to purchase a single skin oil tank or a ‘bunded’ oil tank. Single skin oil tanks are made using just one tank wall, i.e. the tank skin. Bunded oil tanks consist of a ‘tank within a tank’ design, which means that your oil and the surrounding environment are protected in the unfortunate event of the inner tank splitting. Single skin tanks are a more environmental hazardous purchase option, as no protection against tank splits and oil spills are offered.

      Should your oil tank split and should an oil spill subsequently occur, the clean-up costs in such an event can reach as much as £50,000 and may not be covered by your home insurance policy.

      Harlequin believes that the materials which it uses to manufacture its tanks, as well as the structural design of its tanks, make them the first choice for oil tank installers across the UK and Ireland.

    • What types of fuel can be stored in a Heating Oil Tank?

      Harlequin Oil Tanks are suitable only for the storage of:

      • Kerosene (C1/C2)
      • Agricultural Fuel Oil (A2)
      • Diesel (D)
      • Home Heating Oil

      All Harlequin Oil Storage Tanks must be installed in accordance with supplied instructions, the requirements of OFTEC Technical Instruction Book 3 and prevailing statutory requirements. Please note that Harlequin Heating Oil Storage Tanks are not suitable for connection to a fuel delivery system incorporating a flexible hose and automatic trigger nozzle.

    • Where can I put my Heating Oil Tank?

      Your oil tank should be located 1.8metres from the nearest dwelling and 760mm from a boundary (e.g. wall or fence). If this is not possible, then a 30 minute firewall is required, which must extend 300mm above and beyond both ends of the tank. Your local building control authority can provide further advice.

    • Can I buy a Heating Oil Tank manufactured by Harlequin online?

      Yes, there are several approved online resellers of Harlequin products. You can also locate your nearest stockist of Harlequin tanks when viewing a specific product.

      You can click the ‘Buy Online’ tab when viewing any product listing in order to be directed to a list of online suppliers of the specific product you are viewing, or you can visit our ‘Buy Online’ page and answer a couple of brief questions in order for us to determine your tank needs.

    • Can I install the Heating Oil Tank myself?

      Oil tanks should always be installed by a trained technician, preferably an OFTEC approved tank installer. We can recommend an OFTEC-certified tank installer as we work very closely with several installers. This allows us to recommend only the best and most reliable installer to our customers.

      As a minimum, all plastic heating oil tanks should be installed on a flat, level, fire resistant surface, capable of supporting the weight of the tank when fully laden. Where concrete slabs are used, they should be at least 50mm thick.

      The base should extend at least 300mm beyond the widest points of the oil tank and fully support the base of the oil tank in its entirety. Piers are not suitable for this purpose and will cause irreparable damage to the oil tank, resulting in premature failure and catastrophic product loss.

      Detailed oil tank base requirements can be found within OFTEC Technical Instruction Book 3.

      With our Harlequin ITE range of oil tanks, there are three types of gauges within the tank pack:

      Apollo Standard Tank Pack
      Includes an Apollo standard oil tank contents gauge which comprises of a tank mounted transmitter unit and plug in receiver unit, along with a bottom outlet kit. The tank transmitter constantly checks the level in the tank and transmits this to a plug-in receiver unit which displays the level on the easy to read LCD screen.

      Apollo Visual Tank Pack
      Includes an Apollo Visual oil tank contents gauge which comprises of a tank mounted transmitter unit and plug in receiver unit, along with a bottom outlet kit. Apollo Visual as well as reporting the fuel level to a plug in receiver also has a built in LCD display on the transmitter incorporating an on tank level.

      Apollo Smart Tank Pack
      Includes an Apollo Smart oil tank contents gauge which comprises of a tank mounted transmitter unit and plug in receiver unit, along with a bottom outlet kit. Apollo Smart Receiver Unit benefits from a mains power supply, and simply plugs into a standard socket, allowing you to monitor oil heating usage from almost any room in your home or office.

      *Please note – the Harlequin HQi range does not include a tank pack.

    • Can I place my Heating Oil Storage Tank indoors?

      Internal oil tanks should never be installed in a habitable area, and should always be contained within a specially constructed, purpose designed, enclosed chamber. Detailed requirements exist for the installation of oil storage tanks within habitable buildings and domestic garages.

    • Can tanks manufactured by Harlequin be damaged by sunlight?

      All Harlequin oil storage tanks are manufactured from a material which incorporates UV inhibitors. These prevent ultra-violet rays from permeating the structure of the tank, thus preventing fuel degradation.

    • Do Heating Oil Tanks manufactured by Harlequin have an OFCERT License?

      Yes. Harlequin bunded oil tanks each have an OFCERT license, meaning they have gone through rigorous testing processes by industry body and leader OFTEC in order to gain approval for use.

    • How close to a boundary can I place my Heating Oil Tank?

      If the tank is less than 3500 litres in capacity, it should not be placed within 760mm of a combustible boundary e.g. a fence.

      This distance assumes that there are no flu outlets or buildings between the tank and the boundary. Where these clearances cannot be achieved, the protection measures noted in British Standard BS 5410: Part 1: 1997 must be provided, by means of a 30 minute fire-resistant wall which extends at least 300mm above and beyond the ends of the tank.

      For tanks with a capacity greater than 3500 litres or for fire barrier construction requirements, please contact OFTEC for advice.

  • Fuel Storage Tanks: Waste Oil Tanks
  • HeatStream
    • How does the HeatStream produce pressurised water?

      The HeatStream utilises mains water pressure to produce pressurised hot water instantaneously through a high surface area extraction coil.

    • How suitable are the Heat Transfer Coils?

      The Heat Transfer Coils which provide the heart of the product are manufactured using only a high-quality Stainless Steel. The coils themselves have been designed to maximise heat transfer and have an unparalleled heat transfer surface area.

    • Is the HeatStream a Thermal Store?

      No, the HeatStream incorporates a static heat transfer medium in order to ensure that no header tank is required, thus utilising the best parts of an unvented cylinder and a thermal store. The Harlequin HeatStream also operates at temperatures like an unvented cylinder, thus reducing costs compared to most thermal stores.

    • Why does the HeatStream use Polypropylene in its design?

      As with plastic pipes, we believe that Polypropylene is a much more suitable product for hot water storage, and it also lets us produce a better designed hot water storage shape; a more compact, square and much more ergonomic design.

    • Can I attach an uncontrolled heat source to the Harlequin HeatStream?

      Yes, it can absorb an uncontrolled heat source in its Triple range of products. The Harlequin HeatStream Triple can also be connected to a gravity circuit. As the heat transfer fluid is open vented, an uncontrolled heat source such as a solid fuel back boiler can be used. The Triple Range will be available in the future.

    • Can the HeatStream create better flow at my taps than an Unvented Cylinder?

      HeatStream will produce similar flows to that of an unvented cylinder, and at similar pressures. Flow rates are generally a function of mains water pressure.

  • HydroStore
    • How long will a Rainwater Harvesting System last?

      The buried components, indefinitely. Components such as the control system, pump and filter have an extremely long working life, and are easy to replace should the need arise.

    • How much does it cost to run the pump?

      It typically takes 1.5- 2.0 kWh to pump 1 cubic meter of water (1000 litres). For a typical house using rainwater for WCs, washing machine and the garden, pumping costs are between 5-10p per week.

    • How often does a system need topping up with mains water?

      A well-designed system with a good match between supply and demand will only need topping up when it has not rained for some time. Severn Trent monitored a domestic system and found that it only occasionally needed to be topped-up. Most of the time the tank was around 50% full (i.e. an ideal balance between having plenty of water to use, and plenty of space to accommodate the next rainfall).

    • Is Rainwater Harvesting only for new builds?

      Systems are best designed-in from the outset but can be retrofitted depending upon the accessibility of pipe work.

    • Is the Rainwater clean?

      The tanks have filters that remove all debris and particles from the water so that the water remains clear. Please note that in the UK, rainwater is not usually harvested for drinking purposes so it is therefore not recommended.

    • Is there a danger of Legionella?

      No, the system does not provide the conditions necessary for the cultivation of Legionella. With the water stored underground it is dark, cool and is kept well oxygenated. Legionella cannot cultivate in these conditions.

    • What happens during a dry spell?

      When there is insufficient water in the storage tank the Rainwater Harvesting System automatically draws water from the mains so that, from the point of view of the user, no difference is apparent.

    • What maintenance is required?

      Typically, washing off the filter (5-minute job with a garden hose) once a quarter is all that is required.

    • Can I drink the Rainwater?

      In the UK, rainwater is not usually harvested for drinking purposes, so it is therefore not normally recommended.

    • Can I get any grants or tax allowances for installing a system?

      At present there is no funding directly aimed at Rainwater Harvesting. It does however qualify for 100% capital allowance relief on commercial premises.

  • Waste Water Treatment Systems
    • Do domestic sewage treatment plants smell?

      No, domestic sewage treatment plants don’t normally emit unpleasant odours when installed and operated correctly and in line with the manufacturers guidelines provided with each system, due to the contained and efficient breakdown of sewage waste. However, if an odour arises, it could be due to improper venting, inadequate maintenance, or system overloading. Regular inspections, proper care, and ensuring the system isn’t overwhelmed by substances like chemicals or non-biodegradable items can prevent odour issues and ensure a smooth-running, odour-free operation.

    • Do sewage treatment plants need emptying?

      Yes, sewage treatment plants require periodic emptying. Over time, sludge accumulates at the bottom of the plant, which consists of solid waste and by-products of the treatment process. This sludge needs removal to ensure the plant’s efficient operation and avoid overflows or system failures. The plants need to be emptied periodically. For Harlequin sewage treatment plants, the desludging interval depends on the usage and the capacity of the system. For example, if only one or two people live in a property, the system will need to be emptied less frequently as one used by 4 or 5 occupants.

      Typically our HydroClear CAP systems will be desludged every 12 months but this depends on household use. 

      For further maintenance tips, check out our guide to Sewage Treatment Tank Maintenance.

      All our plants must be maintained in accordance with the installation guides that are provided with each system.

       They are also available to read / download from our website:

      Continuous Aeration Plants (CAP)

      HydroClear Sewage Treatment Plant

      Commercial Sewage Treatment Plants

    • How much does it cost to run a domestic sewage treatment plant?

      Running a domestic sewage treatment plant is a cost-effective solution for wastewater management. A HydroClear 6 will use around 1.1 KWh electricity a day. If you paid 20p per kWh for eelctricty this would mean a cost of 22p per day. While costs vary, they’re primarily influenced by the plant’s size, how it is powered, electricity rates, and maintenance requirements. A larger plant may have higher energy demands, but economies of scale often offset this. Regular maintenance, although an expense, ensures longevity and efficiency. The amount of energy consumed will depend on the size of the air blower.Remember, investing in a well-run sewage treatment system means safeguarding your home’s environment and upholding high sanitation standards, which is a worthwhile commitment.

    • Can I install a sewage treatment plant myself?

      While technically possible, installing a sewage treatment plant yourself is a complex task and it’s strongly recommended to use a professional installer. Proper installation requires understanding ground conditions, ensuring the system is level, connecting pipework, and setting up electrical components. Mistakes can lead to inefficiencies, system failures or even environmental issues. A professional installation ensures compliance with  regulations and optimal system performance. 

      If you’re considering self-installation, we offer this comprehensive guide on how to install sewage treatment plants.

      You might also find our guide to wastewater treatment for self-build projects useful.

    • How far should a sewage treatment plant be from a house?

      Building Regulations require that the minimum distance between septic tanks and a house is 7 metres. However, these are standard guidelines and can change based on specific site conditions and local regulations. Besides the house, consider other distances like proximity to water sources, boundaries, and roads. It’s essential to consult local regulations and seek expert advice, ensuring all distance requirements are met and to optimise system effectiveness.

       We’ve put together a comprehensive guide around the sewage treatment plant regulations for your convenience. 

    • What should I consider before a sewage treatment plant installation?

      Before installing a sewage treatment plant, ensure you meet UK legal requirements, including obtaining necessary permits and ensuring the system meets discharge standards. In certain cases, the Environment Agency Permits will be required to discharge treated wastewater. Failure to obtain the correct permit could lead to fines and delays to home conveyancing.

       Consider depth of bedrock, height of water table, proximity to source buildings, access for work vehicles, available area for discharge, slope of the land as these factors influence system effectiveness and placement. Always consult with our professionals to ensure appropriate installation. If you’d like to understand the factors that need to be considered before installing a sewage treatment plant read our guide to off-mains drainage systems.

      All our plants must be installed in accordance with the installation instructions that are provided with each system.

      They are also available to read / download from our website:

       Continuous Aeration Plants (CAP)

      HydroClear Sewage Treatment Plant

      Commercial Sewage Treatment Plants

    • Do I need a septic tank or sewage treatment plant?

      The septic tank regulations under the General Binding Rules of the Environment Agency applicable to England and Wales prohibit the use of septic tanks without a drainage field or main sewer connection, meaning sewage treatment plants are often the preferred option as the output liquid is discharged to a watercourse. As per the new regulations, septic tanks cannot discharge into any watercourse such as ditches, streams, canals, rivers, or surface water drains. So, if a property such as a home, hotel or commercial building has a septic tank system that currently discharges directly into a watercourse, it must be replaced or upgraded with a full sewage treatment plant. Before you replace or upgrade your existing septic tank system, it is important to fully understand the regulations and act accordingly.

      Environmental impact, local council rules, property size, maintenance, running costs, performance, lifetime costs, budget, aesthetics, type of wastewater treated, input loadings, quality of effluent output, proximity to properties, discharge point and site access are some criteria that need to be considered while making a decision.

      If you are discharging sewage waste to a Watercourse (Running Ditch, Stream, or River) you will have to install a Sewage Treatment Plant not a Septic Tank. If you are discharging Sewage Waste to a Drainage Field, you may be able to install a Septic Tank or a Sewage Treatment Plant. Contact our wastewater experts today for guidance on choosing the right solution.

    • What is the difference between a septic tank and a sewage treatment plant?

      Septic tanks and sewage treatment plants treat wastewater differently and therefore provide different outputs.

      Septic Tanks are suitable for specific applications where further biological treatment  occurs typically via a properly constructed drainage field to break downammonia and other pollutants not treated by a septic tank in order to leave the water safe for the environment. 

       A sewage treatment plant, however, processes wastewater more thoroughly. Beneficial bacteria actively degrade organic matter in specific zones, ensuring a higher purification level. Sewage Treatment Plants treat the liquid from the sewage to create a clear odourless liquid suitable to discharge both to watercourse and drainage fields in most cases. Most Sewage Treatment Systems require very little maintenance. In most cases Sewage Treatment Systems require an electricity supply but modern systems require very little energy to operate.

       This means septic tanks produce only partially treated water and sludge, while sewage treatment plants yield cleaner, more environmentally friendly discharged water and reduced sludge. Typically, the pollutant level of the water will only have been reduced by around 30%-40% with a septic tank as opposed to a high degree of 97.5% removal from a modern sewage treatment plant.

    • What is the minimum size of a sewage treatment plant?

      A 2-3 bedroom home will typically need a 6 population equivalent treatment system. This is typically the smallest unit installed although smaller units are available in the market for smaller requirements but these are rare. 6 population systems are suited for a household of up to 6 residents, this compact system efficiently manages wastewater for smaller homes. Therefore, if you have a property with one to two bedrooms or a household with limited wastewater output, our 6-pop plant would be an ideal choice, ensuring effective treatment while optimising space. Always ensure the system matches your property’s needs for best results.

    • What sewage treatment plant size do I need?

      Typically domestic sewage treatment systems are sized by the number of bedrooms rather than the number of people currently residing in the dwelling. Reference is made to British Water guidelines  “Flows and Loads” document as the generic standard. Also consider the type and amount of wastewater produced, especially for high-output businesses like restaurants. Contact our wastewater experts today for guidance on choosing the optimal size sewage treatment plant for your needs.

    • What are the different types of sewage treatment plants?

      There are several types of sewage treatment plants in the UK, including Mixed Bed Biofilm Reactor Plants (MBBR) Activated Sludge Process Plants, Fixed Bed Reactor Plants, Non-Electrical Filter Systems, Rotating Disc Systems, Sequence Batch Reactor Systems, and Submerged Aerated Filter Plants.

      In Activated Sludge Plants, an air diffuser keeps the bacteria alive by providing them with oxygen. The bacteria help to break down the solids/sludge inside the system. A Fixed Bed Reactor system combines both media and aeration to treat sewage waste. Non-Electrical Treatment Plants do not require any power to the unit as everything is treated via gravity however typically involve replacing filters. 

       Rotating Disc Systems use discs to support bacteria growth and keep rotating in a circular motion. Sequence Batch Reactor systems use air diffusers to feed the natural bacteria in the tank with the oxygen they need to survive. The sewage is processed in batches. 

       The MBBR plants are highly effective as they work on a biological treatment process that utilizes floating plastic media within the aeration tank. As the effluent passes over the media, it is purified by microorganisms growing on the surface. The media provides increased surface area for the microorganisms to attach and grow. The increased surface area reduces the footprint of the tanks required to treat domestic wastewater. All Harlequin sewage treatment plants use the MBBR process to treat domestic wastewater. MBBR systems also benefit from plastic media movement which acts to remove dead bacteria from the media keeping the system optimised at fuel treatment levels.

    • How do sewage treatment plants work?

      Domestic Wastewater from a property feeds directly into the primary chamber of the treatment plant. Solid matter settles at the bottom of this tank and begins to biodegrade via an anaerobic process. Effluent from the primary settlement zone then flows into the secondary / reactor zone. A bubble air diffuser is positioned at the bottom of the reactor zone creating an oxygen rich environment much like the process used in a fish tank while also ensuring that the media is always moving freely. As the effluent passes over the media, it is purified by microorganisms growing on the surface. There is a small green weatherproof housing at ground level with an air compressor circulating the media and the liquids.

       Finally, the treated effluent flows into the final settlement zone where very small levels of remaining solids settle to the bottom, after which the final effluent flows through a gravity outlet or pump directly to a watercourse or drainage field dependent on-site conditions.

    • What is a Sewage Treatment Plant

      A sewage treatment plant is a solution designed to clean domestic wastewater from individual homes, small communities, farms, and caravan parks. Typically made from durable Medium Density Polyethylene (MDPE) or high strength Glass Reinforced Polyester (GRP), it resembles a large storage tank and is typically located underground. Its primary role is to collect, store and treat wastewater making sure it’s safe to return to the environment.

       It takes wastewater from toilets, bathrooms, kitchens etc… and treats sewage waste to an acceptable quality for discharge into a watercourse such as a river or stream.  Sewage Treatment Plants play an important role in protecting our environment from pollution and safeguarding public health, as untreated sewage can harm our ecosystem and spread diseases.

    • How much electricity does the plant consume?

      Septic Tanks do not utilise any power. 6 population plants such as the HydroClear utilise 60-80watts, like that of a light bulb.

    • My septic tank/treatment plant smells. Why is this happening?

      The most common reasons are an incorrect venting arrangement, a lack of maintenance or incorrect operation. The wastewater tank as well as the drainage pipes need to be sealed, venting to an appropriate dispersal point. This includes sealing all access points in the drainage pipes and u-bends on pipes in the dwelling. Maintenance and correct operation (use of detergents etc.) is vital to ensure that the system is physically and biologically treating the wastewater correctly.

    • What can I do if my site fails the ‘percolation test’ and I do not have a watercourse to discharge into?

      There is provision in the building regulations to construct an artificial ‘soakaway mound’, although this will need to be properly designed by a competent engineer or specialist drainage consultant.
      Another option is to pump the treated wastewater to a location with suitable porosity or available surface water discharge point. Pumping to a main sewer connection may also be an option.

    • What distance from the property does the plant need to be?

      A minimum of 7m should be used, increasing to 25m if serving more than one building. Some local authorities will permit significantly closer installations if it is as far as is practicably possible. Your building control officer should always be consulted early in the planning stage regarding the location of the treatment plant.

    • What is Sewage Treatment?

      Sewage treatment is the physical, chemical or biological process of removing contaminants from wastewater or sewage. This can be required for domestic, agricultural or commercial properties. The objective is to produce an environmentally safe fluid.

      Mains Drainage
      The majority of houses in the UK are linked to the public sewerage system. You pull the plug, flush the toilet, pay the monthly bill and have little more to worry about. This is known as mains drainage.

      Off-Mains Drainage
      In rural areas many homes and villages are self-contained. Either a cesspool, septic tank or sewage treatment plant will be used. This has no connection to the public sewerage system and is known as off-mains drainage.

    • What is the difference between a silage tank, a septic tank and a sewage treatment plant?

      A silage tank or cesspit collects and stores all the raw wastewater and must be emptied when full. These are not permitted in Scotland. A septic tank physically separates the solids from the liquids; the liquid is allowed to flow out of the tank, usually for dispersal by a network of underground perforated pipes called a soakaway. A sewage treatment plant works like a septic tank but has an additional stage to treat the liquid removing the dissolved constituents. The quality is then enough for direct discharge to surface waters.

    • Will a soakaway drainage system become blocked up after several years of use?

      If the soakaway system is laid properly according to the percolation test and BS 6297:2007, it will last for many years. Organic matter can eventually build up with the distribution network; it is therefore important to recognise that a soakaway system will not last forever. Proper maintenance and desludging of the tank is the most important factor in maximising the life of the soakaway.

    • Will paper towels, sanitary towels, etc. clog up my system?

      Sanitary towels and similar non-biodegradable products should not be flushed into any wastewater treatment tanks.

    • Can I use normal detergents and cleaners and will they affect my plant’s performance?

      Yes, normal domestic use of these products is acceptable to the plant biology. If higher than normal quantities are expected, you should contact Harlequin before purchase.

    • Does the plant make a noise?

      Modern compressors are virtually silent, contained within housings further reducing noise levels.