Sewage Treatment Plants, Cesspools, and Septic Tanks FAQs: Your Comprehensive Guide

Maintaining a sewage treatment plant involves two main aspects. Firstly, it's important to adhere to the desludging schedule provided by the manufacturer. This means arranging for the tank to be emptied at the recommended interval, which can range from six months to two years depending on the system. This ensures the continuous operation and effectiveness of the treatment process.

Secondly, engaging the services of a qualified engineer to regularly service the system is crucial. During the service, the engineer will assess the system's performance, including the quality of effluent discharge and the functioning of components. It's essential to understand that a treatment plant supports the biological process by increasing oxygen levels, which is vital for the system's success.

Having an understanding of how the treatment plant operates is valuable for homeowners, as it enables them to take an active role in maintaining their system. For commercial applications, maintenance is typically handled by the responsible authority. Regardless of the setting, comprehending the biological process and its purpose in promoting water quality is important to protect the environment.

By following these maintenance practices and ensuring an adequate oxygen supply, sewage treatment plants can effectively treat wastewater and discharge high-quality effluent to safeguard the environment.

There are three ways water can be moved out of a tank. For septic tanks, gravity is commonly used, where the water level remains static. In systems like our Graf treatment plants, we use airlifts to lift the water out of the tank, similar to pumping. This allows for a lift to the same level as the inflow or even higher for raised discharge.

The second option is an electronic pump. This can be incorporated into the septic tank or treatment plant itself, using a pump on a float switch inside the tank or an external pump chamber. A pump is necessary when the water needs to be lifted to a higher location, such as a garden or a car park.

While pump solutions are available, manufacturers generally try to avoid them due to the reliance on electronic elements. Power cuts can cause issues with pump operation. It is recommended to minimise the use of electronic pumping elements when possible. For treatment plants with pump solutions, external pump stations are preferable for easier access, maintenance, and servicing.

Considering the specific needs and circumstances, customers should carefully weigh the options and choose the most suitable method for their situation.

In general, septic tanks and treatment plants are designed to be underground, providing natural insulation from frost. The soil acts as a protective layer to prevent the water in the tank from freezing. When wastewater is discharged from the property, it is relatively warm compared to freezing temperatures in the ground. This helps maintain a higher water temperature within the treatment plant.

For the biological processes in the tank to work effectively, the water temperature needs to be above 12 degrees Celsius. If the water level is nearing freezing, it indicates a serious problem with the biological process. In such cases, insulation options should be considered to protect the tank.

Customers may also want to consider shallow dig septic tanks, which are closer to ground level. However, this can make the tank more susceptible to colder temperatures. Nevertheless, in the UK, it is unlikely that temperatures will drop low enough for the water inside the tank to freeze. If customers have concerns, opting for a deeper installation can provide added assurance.

The purpose of a sewage treatment plant is to protect the environment by improving the conditions for bacteria inside the tank. These bacteria break down the incoming wastewater, resulting in high-quality effluent that can be safely discharged. The main goal is to ensure the effective treatment of wastewater and minimise its impact on the environment.

It's important to be mindful of what you flush down the toilet if you have a wastewater tank. Avoid pouring fats, oils, and greases down the sink as they can cause issues. Use cleaning products in moderation, especially avoiding chlorine-based ones. Certain items like wet wipes, cotton buds, sanitary towels, razor blades, and non-biodegradable materials should not be flushed. Hair can also wrap around components and hinder the system's operation. Even if it's not the homeowner's doing, such as during renovations, substances like paint and thinners should be kept away from the treatment plant. Being responsible with what goes into the tank helps maintain its effectiveness.

Bleach and detergents can be used with a septic tank, but it's important to use them in moderation. Regular household use is generally fine, but excessive use or introducing aggressive cleaning products from holiday home cleaning can disrupt the tank's biological process. Consistency is key, and using washing detergents that are more friendly to the tank's bacteria is recommended. It's best to avoid chlorine-based products as they can be harsh on the tank's ecosystem.

When it comes to tank positioning, it's important to consider the guidelines in building regulations. Ideally, the tank should be installed seven meters away from the property. However, if that's not possible, you can find the best alternative. Keep in mind the access for the de-sludging vehicle that will empty the tank. They typically use 30-meter-long suction lines. While it's possible to install a tank at the front of your property, it's important to be mindful of potential odours if the tank isn't functioning properly. Placing it near windows or patios may result in noticeable smells. Consider the optimal position for your project, whether it's at the front or elsewhere, and make sure it's convenient for the de-sludging process.

To clean a wastewater tank, a desludging company needs access to the tank. They can either use a shaft or open the main manhole cover. The company will empty the tank based on the manufacturer's guidelines and the sludge storage volume. They will suction the waste and transport it to a municipal treatment plant for offsite treatment.

A septic tank is a holding tank for wastewater. It separates the sludge through baffle walls and allows the settled sludge to remain in different chambers. The liquid waste is discharged through an outlet into a drainage field, following the code of practice. Upgrading from a septic tank that discharges into a watercourse is recommended. The treatment process primarily involves the settlement of sludge and extracting water while preventing solids and scum from reaching the drainage field. This helps maintain the drainage field's lifespan and keeps the sludge inside the tank.

To calculate the size of a septic tank, start with a minimum base volume of 2,000 liters. Then, consider the source of waste and refer to the Flows and Loads guide from British Water. It provides the liters discharged per person per day for different types of properties. For example, a standard residential dwelling may have 150 liters per person per day. Multiply this by the population to get the daily volume. Add it to the base volume to determine the required storage volume.

For instance, a five-person household would be 5 x 150 = 750 liters per day. Adding this to the base volume of 2,000 liters gives a required storage volume of 2,750 liters. It's important to choose a tank with a volume equal to or larger than this.

Consider the specific requirements of your property. For example, in an office building with 10 full-time staff members, if each person generates 90 liters per day, the calculation would be 10 x 90 = 900 liters per day. Adding this to the base volume gives a required storage volume of 2,900 liters.

Keep in mind that the desludging interval will depend on the tank manufacturer and may vary. It's essential to gather this information from the customer before making a decision.

Determining the level of sludge in your tank depends on whether you have a septic tank or a wastewater treatment plant. For septic tanks, you can use a simple method. Insert a stick into the tank, lift it up, and measure the marking on the stick to determine the sludge level. This can be compared to the recommended maximum level provided by the manufacturer.

For wastewater treatment plants, a Sludge Volume 30 (SV30) test is commonly performed. This involves taking a sample of sludge from the plant and allowing it to settle in a measuring cylinder for 30 minutes. The volume of settled sludge at the bottom compared to the liquid layer on top indicates the sludge percentage in the tank.

For accurate results, it's recommended to have a professional service provider perform the SV30 test. They can also carry out other checks on the system components during the same visit. Performing the SV30 test at the beginning of the service allows the settling process to occur while other checks are conducted.

It's important to know the sludge volume in your tank to plan for necessary maintenance, such as tank emptying. Consulting the manufacturer's guidelines and working with a professional servicing company can help you determine the sludge volume and maintain your system effectively.

Septic tanks are like old technology. You will see septic tanks built from many years ago. That is all dependent on what the tank is made from. Some older generation buildings, they have got brick tanks and those tanks will start to degrade over time. If you were to pump them out, you will just see that the surface walls of the tank starting to wear over time. More recently, we are looking at plastic tanks but still can get some concrete tanks.

Lifetimes on these tanks could range based on the quality of the plastic like reinforced plastic or HDP, which we use. It could be anything from 15 to 25 years, and then service life could go beyond that. There is not reason why it can’t go beyond if it is installed as per the manufacturer's installation instructions. However, there are some limiting factors, especially in the UK in terms of ground conditions. You might need to ask the manufacturer’s advice if you have got challenging circumstances you need to overcome. The surface like can be anything from up to 25 years on a plastic tank.

Yes, a sewage treatment plant requires a discharge point for the treated water. Traditionally, septic tanks would use a soakaway or drainage field, and treatment plants can also utilise these options. However, treatment plants offer the additional possibility of discharging into a water course. It's important to consider the permitted flow limits when discharging to a water course and obtain the necessary permits if exceeding those limits. Regardless of project size, discharge options need to be carefully evaluated when using treatment plants.

A treatment plant itself does not typically cause odour issues. However, sudden changes in the system's environment, such as increased flows or the use of different cleaning products, can lead to smells generated by the treatment process. To prevent odours from entering the house, it's important to have proper ventilation and water traps installed in the discharge pipes of sinks and showers. Consistency in the use of cleaning products and maintaining a stable environment in the treatment plant helps keep the biological process balanced and odour-free. Implementing effective ventilation systems and directing foul air away from living areas is essential. Proper design and installation of the wastewater treatment system can prevent odour-related disturbances for homeowners.

It is generally preferred to have a septic tank installed in a way that allows for gravity discharge rather than uphill installation. When a septic tank needs to be installed uphill, a pump station or chamber is required to push the water uphill. This adds additional cost and maintenance as the mechanical pump in the chamber needs to be serviced and monitored. If the pump fails, there can be a backup of foul water. Most manufacturers offer pumping station options, but it's important to consider the ongoing maintenance and servicing requirements.

It is advisable to keep rainwater away from septic tanks and foul water treatment plants. Rainwater can disrupt the biological process within these systems. As the future trend is shifting towards treatment plants, it is important to divert rainwater from foul water discharge. Connecting rainwater to septic tanks can cause flooding during heavy rainfall. It is recommended to size tanks properly and consider expected foul water flows and storm events. Keeping rainwater and stormwater separate from foul water discharge is good practice to avoid potential issues.

The maintenance schedule for treatment plants can vary based on whether it's a domestic or commercial system. For domestic systems, we recommend that homeowners have a general understanding of how the system works and perform regular checks. It's also advisable to have a professional service provider inspect the system once a year to ensure it's working properly and the effluent quality meets standards.

Commercial systems, on the other hand, typically require ongoing maintenance and have designated personnel responsible for their care. These individuals should have a good understanding of the system, its operation, and troubleshooting procedures. Commercial treatment plants usually undergo maintenance twice a year, and if additional modules are present for phosphorus removal, maintenance may be required more frequently, potentially three to four times a year.

Maintenance also includes the desludging of the tank, which has a designated volume specified in the technical data sheets. The interval for desludging can range from 6 to 12 months, depending on factors such as the number of people served and the size of the treatment plant.

It's important to consider these maintenance requirements to ensure the optimal performance and longevity of the treatment plant.

Our treatment plants operate using a sequence batch reactor (SBR) technology, which sets them apart from competitor systems. While power is supplied to the treatment plant continuously, the control technology regulates its operation. Our systems follow an interval-based biological process, where power is directed to the compressor and valves at specific times throughout the day.

In total, the compressor typically runs for about 12 hours a day, unlike competitor systems that may run continuously. Although domestic compressors consume minimal energy, those concerned about energy consumption may find the SBR option appealing, as it runs the system for less time, potentially resulting in energy savings.

It's important to note that SBR systems utilise airlifts and intermittent aeration for different stages of the treatment process, such as organic material breakdown and nitrification. Therefore, it's crucial to maintain continuous operation to ensure the effectiveness of the biological process. Turning off the system during the night is not recommended.

When considering the installation of a wastewater treatment system, it's advisable to place the compressor in an area where noise and vibration won't cause disturbance to you or your neighbours. Being mindful of these factors will contribute to a smooth implementation of the system.

With Graf systems, we have a control panel that supports the operation of the system. If there is a fault or warning, a red light and possibly an audible sound will indicate the issue. For the biological process, it's important to only introduce domestic waste and water into the tank. When non-biodegradable substances or high volumes of bleach are added or there are inconsistent fluctuations in waste input, it can disrupt the biological process. This disruption can lead to odours generated by bacteria. Smells coming from the system indicate that something may be wrong underground. Good treatment performance should not produce any smells.

For holiday homes or properties with irregular usage, installing a ventilation system can help redirect any foul water smells away from the property. It's crucial to be mindful of evaporating water from sinks and showers in unoccupied periods, as this can lead to odours flowing back into the property. However, if the treatment plant is functioning well, there should be no cause for concern. Smell is often the initial indicator of any issues with the vital process or control panel operation.

Venting a septic tank is essential to ensure proper airflow and prevent potential odours. It involves incorporating both a low level vent and a high level vent in the system.

The low level vent is placed after the septic tank, treatment plant, or cesspool. It allows air to be drawn in from the surrounding area. The high level vent is located at the inflow point and serves as an outlet for the air.

Depending on the site conditions, you may have spinning cowls, one-way valves, or fans integrated into the ventilation system to promote airflow. In areas with good wind flow, natural ventilation is often sufficient. However, in enclosed spaces, additional measures may be needed to encourage airflow.

For modern developments with internal soil stacks, it's beneficial to include an external high level vent that extends above the roof or another suitable location, such as a shed or garage.

By incorporating both low level and high level vents, a septic tank can be properly vented, allowing for the flow of air and preventing any potential odour issues.

When it comes to discharging into a watercourse, it's important to refer to the code of practice, specifically 12566-3, which applies to wastewater treatments. For our wastewater treatment systems, if the volume of treated water being discharged is less than five cubic meters, it can go directly into a watercourse without permits. However, if the volume exceeds this, a discharge permit is required to assess the potential environmental impact.

The code of practice sets guidelines for certain effluent parameters, including BOD (biochemical oxygen demand), suspended solids, and ammonia. The standard rule is to achieve 20 milligrams per litre for BOD, 30 milligrams per litre for suspended solids, and 20 milligrams per litre for ammonia. These parameters may vary depending on factors such as protected areas or specific project requirements.

Some projects may have stricter effluent parameters or additional treatment requirements, such as nitrogen and phosphorus removal. In such cases, additional modules can be added to the treatment system to target and reduce these levels further. However, for most cases, meeting the 20, 30, 20 parameters and discharging less than five cubic meters per day is sufficient for direct discharge into a watercourse.

When you purchase a treatment plant system from us, the supply includes two separate pallets. The first pallet contains the tank itself, fully assembled and ready for installation. It includes components such as the diffuser, airlift, sump, and chamber. The second pallet contains accessories and controls for the system. This includes lids, air hoses for the airlift and diffuser, as well as the control panel and compressor. For advanced systems, additional components like pumps, dosing equipment, and remote modems are included on the accessory pallet. We also offer housing cabinets for both internal and external installations.

The running costs of the GRAF One2Clean sewage treatment system are generally very low. The system utilizes sequence batch reactors (SBR) and runs the compressor for only 8 to 12 hours a day, compared to other systems that run 24/7. This reduces energy consumption by up to 50% or more. The exact cost of running the system will depend on the size of the treatment plant and the homeowner's electricity rates. On average, for a 5-person system, it is estimated to be around 46 kWh per person per year, which is relatively minimal. For specific cost calculations, further information from the customer is required. Please reach out to us with any direct questions about running costs.

The likely failures of a wastewater treatment system are typically related to electrical issues and improper understanding or care of the system. It's important to remember that the treatment system relies on a working biological process, so it's crucial to only allow biodegradable items into the tank and avoid introducing plastics, rubber, cans, and excessive amounts of cleaning products that can disrupt the biological process. Achieving a balance in the tank is essential for optimal performance.

The system's components will also experience wear over time. Compressors, such as diaphragm, piston, or rotary vane compressors, have specific maintenance requirements outlined in the installation instructions. This may include regular cleaning or replacement of air filters and blades. It's recommended to consult the service manual provided by the manufacturer for a better understanding of the maintenance procedures.

If you have concerns or want to learn more about your system, it's advisable to seek the assistance of a competent service engineer who can provide maintenance services and offer on-site advice. At Graf, we offer flexible options for sending engineers to help you understand and optimise your system's performance.

The benefits of using Graf systems over competitor systems are centered around adaptability and control. The control panel in Graf systems allows for flexible adjustment of oxygen levels within the tank, optimising the breakdown of organic material and enabling effective treatment of nitrogen compounds. This results in a higher quality discharge. Compared to other systems that run compressors 24/7, Graf systems offer greater control and targeted treatment.

Installation is also more convenient with Graf systems. Instead of requiring concrete backfill, a gravel base can be used, providing flexibility and saving time during installation. Additionally, the absence of moving components within the underground tank simplifies servicing and maintenance. The controls and software are located separately, allowing easy access for system checks and troubleshooting without the need to enter the tank.

In case of any issues, the control panel and compressor provide a clear indication of the system's performance, minimising the need to enter the tank for troubleshooting purposes.

If you need help sizing your wastewater treatment plant requirements and you're interested in a GRAF system, simply contact us. You can start by downloading the Flows and Loads guide from the British Water website to get an understanding of the parameters involved. Then, reach out to us, and we'll guide you through the process, discussing your project requirements. Together, we'll determine the appropriate system size for your needs. Once you're satisfied, we can design and implement the system accordingly. So, if you want a GRAF treatment plant and assistance with sizing, give us a call. We'll be there to help you every step of the way.

Wastewater treatment systems require regular maintenance, which can be divided into two areas: servicing and de-sludging. For domestic systems, we recommend an annual servicing visit by an engineer to check the treatment process and component health. Commercial systems may require a minimum of two visits per year due to their larger size and more components. Additional modules, such as phosphorus mitigation, may require three to four visits to ensure compliance with discharge parameters.

The de-sludging interval is determined by the size of the primary catchment chamber. Domestic systems typically require de-sludging every 12 months, while commercial systems may need it every six months or even more frequently. It's important to conduct the servicing before de-sludging to assess the treatment plant's performance accurately.

By maintaining a regular servicing schedule and adhering to de-sludging intervals, you can ensure optimal performance and longevity of your treatment plant.

The water discharged from a wastewater treatment plant is not drinkable, despite some claims in the industry. However, the water is generally very clean with only slight coloration due to suspended solids. The treatment process aims to meet quality parameters set by regulatory standards. These include limits for BOD (biological oxygen demand), suspended solids, and ammonia. Most treatment plants exceed these standards. It's important to note that pathogens and microorganisms may still be present in the water. Future technologies like disinfection with UV or chlorine may further improve water quality, potentially allowing for reuse in gardens. However, there is currently no certification in the UK for drinking treated wastewater. So, while the water is of high quality, it is not suitable for drinking.

Treatment plants and septic tanks generally don't produce smells if they are working properly. To maintain a good environment for the bacteria inside the tank, it's important to avoid introducing non-biodegradable items like wet wipes and plastic. Sudden changes in the tank's conditions, such as emptying the tank, can also cause temporary smells, but ventilation systems can help disperse them. It's advisable to avoid sudden changes in chemical usage, like using excessive bleach or doing multiple loads of laundry in a short period, as this can disrupt the bacteria's environment and lead to odours. Proper ventilation and spacing out activities that may affect the tank's conditions can help minimise or eliminate smells.

For smaller systems, a 220-240V supply with a 13 amp main socket is typically needed. It's recommended to have a dedicated supply from the fuse board for easier maintenance. Commercial applications may require three-phase power, which requires an electrician to handle the connections. We design control cabinets based on specific site requirements for commercial setups. However, for residential applications, a simple mains socket with a 13 amp capacity is sufficient for the system.

For domestic applications, it's generally recommended to leave the system running even when going on holiday. The energy consumption is low, similar to a light bulb, and keeping the system working maintains its optimal performance. However, for larger commercial systems, a holiday mode can be beneficial to reduce energy usage and maintenance requirements. In such cases, the system control panel allows for selecting holiday mode to adjust compressor runtime, and it can be restored upon return.

If the homeowners will individually own the sewage treatment systems, it is generally recommended to install separate systems for each property. This helps to avoid potential conflicts and maintains good relationships between neighbours. Each homeowner will be responsible for the maintenance and servicing of their own system.

However, if the local council will handle the maintenance and servicing of the systems, it may be more feasible to install a larger treatment plant that can serve multiple properties. In this case, the council will take care of the system's upkeep, servicing, and emptying. This helps prevent any disagreements among neighbours regarding the cost and responsibility of maintenance.

It's worth noting that local authorities often encourage the installation of larger systems when feasible. Homeowners should consider these factors when deciding whether to install separate systems or a shared treatment plant.

To determine the size of a wastewater treatment system, you can refer to the Flows and Loads guide available on the British Water website. This guide provides information on different sources of waste and their corresponding flow rates, organic material (BOD) concentration, and ammonia levels. Based on these parameters, you select a system that can handle the highest concentration among the three.

For small domestic applications, you can consider the number of bedrooms in the property and add a certain number to determine the system size. For larger projects or commercial applications, it's best to seek advice from experienced professionals who can assist in selecting the appropriate system size.

Manufacturers are familiar with the Flows and Loads guide and can provide guidance and support in determining the right system size for your specific needs.

When considering the need for an external cabinet for your wastewater treatment system, there are a few factors to consider. Firstly, there is usually a recommended distance between the control panel and compressor and the underground tank, typically within 20 meters, to ensure optimal airflow for system operation.

An external cabinet provides several benefits. It allows you to locate the control cabinet in a more convenient or suitable location. Additionally, it helps reduce the sound and vibration generated by the working compressor, improving overall system comfort.

Furthermore, it is recommended to have your wastewater treatment system serviced and maintained regularly. Having an external cabinet provides easier accessibility for maintenance and servicing by engineers.

Considering these factors, an external cabinet can be beneficial for optimising system performance, convenience, and maintenance.

Determining when a septic tank needs to be emptied can be done in a few ways. First, you can check the designed storage level provided by the manufacturer and consider the tank's volume and the number of people using it. If the tank is designed for more occupants than you have, it will likely last longer before needing to be emptied. Typically, septic tanks can last anywhere from six months to a year before requiring pumping.

For a more accurate measurement, sludge level pipettes can be used. These dipsticks can gauge the amount of sludge volume in the tank, and the manufacturer will provide the maximum volume before it needs to be discharged. However, this measurement is often carried out by a service engineer, especially for treatment plants.

While septic tanks require less monitoring, it's still important to consider the sludge levels and the recommended frequency for emptying to ensure proper maintenance.

The purpose of a treatment plant is to reduce the concentration of ammonia in waste water, rather than producing ammonia. However, in certain cases, if you want to extract ammonia for other applications, it would need to be done at the source. For example, in a commercial or domestic building with urinals, urine can be collected separately and taken off-site for alternative use. But generally, the goal of a treatment plant is to minimise the ammonia concentration in the tank to minimise its impact when discharged into the environment.

The main difference between our one-screen system and our advanced wastewater treatment systems lies in the level of technology and targeted treatment they offer. The one-screen system is a standardised option that effectively breaks down components like BOD, suspended solids, and ammonia according to industry guidelines. It is designed to deliver high-quality effluent for domestic applications.

On the other hand, our advanced systems, such as the Klaro systems, utilise more sophisticated technology. These systems incorporate features like dosing pumps, chlorine reaction chambers, and UV treatments, allowing for targeted treatment of specific parameters. They are capable of achieving exceptional effluent quality and are particularly useful in projects that require nitrogen and phosphorus reduction.

In summary, the one-screen system is a reliable choice for domestic needs, while our advanced systems provide enhanced control and customisation to meet specific customer requirements.

In general, it's recommended to install a sewage treatment plant at least seven meters away from a property. This helps prevent any potential odor issues and ensures the system functions properly. However, not everyone has enough space for this distance or access to a suitable drainage field located 15 meters away. In such cases, it's important to consult with the building authority responsible for approving the project to find the best possible solution that meets the regulations and requirements of the specific situation. Working together, a compromise can be reached to ensure an appropriate installation.

To determine if your septic tank is full, it's best to take a proactive approach. Find out the size of your tank and consult the manufacturer's guidelines on storage capacity, which can vary based on tank size and usage. Another method is to lift the tank cover and use a stick to measure the amount of solid waste present. This gives an accurate assessment of tank fullness. Reactive indicators of a full tank include foul odors emanating from the tank and potential backups in drains. Additionally, if your lawn is unusually lush near the drainage field, it may suggest an excess of nutrients, but it's worth investigating if the system is backed up. It's important to be mindful of both proactive and reactive signs to understand the status of your septic tank.

The frequency of emptying a sewage treatment plant is typically recommended by the manufacturer. For domestic systems serving a single dwelling, it is often advised to have the system emptied once a year. It is good practice to leave some activated sludge in the tank during emptying to maintain the performance of the bacteria. The size of the system and the number of people using it should also be considered. Systems are usually oversized, providing a buffer and potential for longer intervals between emptying if there is low loading. Additional factors to consider are whether homeowners are using feeders or reducers to improve performance and reduce sludge accumulation. Feeders introduce bacteria-enhancing substances, while reducers help maintain an optimal sludge level of around 40 to 60%. The use of such products can extend the time between emptying. Commercial systems may require more frequent emptying, typically two to four times a year, depending on the application and waste volume.

When it comes to sewage treatment plant discharge, the quality of water is better compared to septic tanks. However, there may still be some biological processes and microbes escaping, which can impact the environment. According to the general binding rules, the discharge should go into the ground or a flowing water course to prevent nutrient retention on the site. The allowed discharge volumes are up to 2 cubic meters per day for underground discharge and 5 cubic meters per day for watercourse discharge, based on population size. If the discharge exceeds these volumes, a permit is required. The permit allows different discharge options, including the possibility of discharging into a pond under specific conditions. To obtain a permit, individuals should contact the local Environment Agency, which will provide guidelines and requirements for the discharge, including the desired quality of effluent. It is important to adhere to the general binding rules, and any exceptions will require a permit for discharge.

Cesspools and septic tanks are both used to collect and treat foul water runoff, but they have significant differences.

A cesspool retains all the liquid waste, including greywater and blackwater, in a tank. When it becomes full, it must be emptied by a tanker. Cesspools require suitable conditions for installation, especially in areas with high groundwater. They need to be sized according to the number of people using them, and they require frequent emptying.

On the other hand, a septic tank is more advanced. It has dividing walls and an outflow. It retains solid waste while allowing liquid waste to discharge into a drainage field, where it undergoes additional treatment as it percolates into the ground. Septic tanks require good soil for percolation and have volume restrictions for domestic use. They need less frequent emptying compared to cesspools.

Septic tanks have a slight environmental impact due to discharging into the environment, but with a properly sized drainage solution, the impact can be reduced. The sludge waste from septic tanks is typically taken to a foul water treatment plant, incurring costs for homeowners. Cesspools have a larger volume capacity and require more frequent emptying, making them less favorable compared to septic tanks.

Ideally, wastewater treatment plants should be considered first, followed by septic tanks. Connecting to the mains water network is the best solution if available. Cesspools are generally used as a last resort.

To determine if a wastewater treatment system is operating correctly, homeowners should have a general understanding of how their specific system works. This knowledge helps identify any issues that may arise. For example, if there are strong odors or problems with the drainage system, it could indicate a full sludge tank or other issues.

Performing daily checks, such as monitoring the system control panel, is essential for homeowners. Additionally, scheduling regular servicing by a knowledgeable engineer is recommended. Different treatment plants have variations, but understanding the working components and knowing what to look for is crucial.

During a service, key parameters like ammonia, BOD, and suspended solids are examined. Additional tests for phosphate concentration, nitrogen, and BOD can be done if required for environmentally sensitive areas. Checking system operation, back pressure on compressors, diffusers, and sludge levels are also part of a comprehensive service.

For GRAF system users, contacting GRAF or their network of service providers is the best option. GRAF offers onsite training and can connect homeowners with qualified service providers throughout the UK to ensure proper system maintenance.

When a sewage treatment plant is overloaded, there are immediate and long-term problems. Treatment systems have a buffer to handle additional short-term loads, but beyond that, issues arise. Smells from the system and compromised treatment performance are immediate signs that something is wrong.

Long-term overloading can lead to problems with drainage solutions, whether it's going to the ground or a watercourse. This has a significant environmental impact and can result in costly repairs for homeowners. Discharging through a watercourse without proper treatment can even lead to penalty fines.

To avoid these problems, it's crucial to ensure that the system is sized correctly from the start. Proper sizing and adherence to manufacturer's recommendations are essential to protect the environment effectively.

Cleaning a septic tank is a crucial task to maintain its functionality and protect the environment. When a septic tank becomes full, it can cause blockages and harm the drainage system. To clean a septic tank, it's best to hire a specialised company with the necessary equipment. They will empty the tank, removing the water and sludge. After cleaning, it's advisable to refill the tank with mains water to maintain stability and prevent external pressures. This cleaning process ensures the longevity and effectiveness of the septic tank system.

Let's clarify the term "septic tank" first. A septic tank is a non-electrical system that separates incoming and outgoing waste through split chambers. The treatment occurs within the tank using dividing walls, and the liquid waste is then discharged into a drainage field for further treatment as it percolates through the ground. Generally, septic tanks do not require electricity.

However, when we mention the use of electricity, we are referring to wastewater treatment systems or package treatment plants. These systems incorporate biological processes to optimise the breakdown of foul water before it is discharged into the environment. So, septic tanks do not use electricity, but wastewater treatment systems do.

There are a few important considerations for maintaining a sewage treatment system:

1. Be mindful of what you flush down the toilet. Non-biodegradable items like plastics, metals, rubbers, wipes, and cigarette butts can cause blockages in the system.
2. Keep the tank regularly emptied to prevent it from becoming too full. An overflowing tank can block incoming and outgoing pipelines.
3. When discharging treated water into the environment, be aware of potential flooding in watercourses or high groundwater levels. These conditions can lead to blockages. Prior research on soil conditions is crucial to ensure the system can handle different weather conditions throughout the year.

By avoiding non-biodegradable items, maintaining the tank, and considering environmental factors, you can prevent blockages and maintain an effective sewage treatment system.

A sewage treatment plant aims to improve the breakdown of foul water that enters the tank. Bacteria are introduced into the tank through the black water from toilets, and they break down the water. To enhance bacteria's efficiency, different types of treatment plants use various methods.

Most treatment plants have a dividing wall that separates the chambers and retains solids in the tank. Water is moved between chambers using pumps or airlifters. Some plants use plastic material called media to increase the surface area for bacteria growth. Filters separate waste and remove impurities. Aeration, the most important process, introduces oxygen into the water, creating a better environment for bacteria to break down the water effectively.

The goal is to achieve high-quality treatment. Each sewage treatment plant improves the living environment, separates waste, and retains it within the tank. Bacteria need food from incoming blackwater and greywater, and we provide oxygen to help them work efficiently.

The treatment process breaks down various compounds present in the foul water, reducing their levels. Treatment efficiency is a measure of how effective a wastewater treatment system is. Different technologies and system types determine how the treatment plant operates.

GRAF systems use dividing walls and aeration processes. Other manufacturers may employ additional components like media, filters, and pumps to optimise treatment performance and achieve desired water quality.

Nutrient neutrality aims to reduce the runoff of domestic foul water from developments to protect the environment. It involves reducing the nutrient runoff on-site and offsetting it through off-site measures. Incorporating an onsite wastewater treatment plant is an effective way to reduce nutrient runoff. However, additional measures are often needed to offset the remaining impact. This can include purchasing land for forestry growth or upgrading other systems that discharge into the same water network. Nutrient neutrality is crucial for preventing algal blooms and preserving aquatic ecosystems. It is a response to the increasing awareness of the environmental impacts caused by nutrient runoff from human activities. Achieving nutrient neutrality requires a combination of reduction and offsetting efforts, such as improving treatment plant efficiency and implementing tertiary treatments like wetlands or reed beds.

If you need help sizing your wastewater treatment plant requirements and are interested in a GRAF system, simply contact us. You can also refer to the British Water website and download their Flows and Loads guide version 4 for more information. Once you have an understanding of your needs, we can discuss your project requirements and guide you towards the right system size. We'll work together to design and implement the system that suits your needs.