0191 5131313 | hello@siris.co.uk
0191 5131313 | hello@siris.co.uk


Case Study: Finding the right flow monitoring solution for a National Park holiday resort


Flow Monitoring Solution for a National Park holiday resort

Our partner commercial drainage specialist Metro Mechanical asked for our help to find a suitable flow monitoring set-up that preserved the natural beauty of a unique National Park setting and provided the end customer with the flow data they needed.

The Challenge

The end customer was a holiday resort in a scenic location within the Lake District National Park. They process high volumes of waste and are charged by volume by the water company, however they didn’t have any way of measuring the amount they were using.


The project was further complicated by a lack of mains power to the remote site.

Alistair, SIRIS Projects

“The client needed a solution that not only provided accurate and reliable data provision, but was sympathetic to the aesthetics of the surrounding environment.”

The Solution

We designed and installed an electromagnetic battery-powered solution, which allowed the customer to monitor its flow data via the cloud without any power. Metro Mechanical built a chamber that allowed access to the flow meter, with a lid enabling it to blend into its scenic surroundings and avoid impacting the landscape.

The Result

We were able to provide a solution that not only ensured effective flow monitoring but also ensured the preservation of the natural beauty of the National Park setting. 

Data Logging Solution

Require Flow Monitoring?

Do you have a flow meter monitoring requirement?  Contact us to understand how you can quickly get a solution to your project.


MCERTS flow measurement: Why it’s essential to consult the experts


MCERTS flow measurement

Why it’s essential to consult the experts

We often get calls from customers requesting quotes for part of a flow system – and they’re often surprised when we explain that it isn’t as simple as just selling them a flow meter.


In this article we explain why installing any MCERTS flow measurement system requires a holistic approach, and the importance of consulting the experts to ensure your system is not only cost-effective but fit for purpose.

“Why do I need to look at the whole system? I just need a flow meter.”

It’s something we hear often. A customer already has a legacy system in place and just wants to replace a small part of it. The problem is, it’s not always that easy.


Over the years our servicing and installation engineers have seen hundreds (if not thousands!) of flow measurement systems, and a surprising number of them simply aren’t fit for purpose – and likely never have been.

While we could just sell you the component you ask for, there’s no guarantee that it will be suitable for your existing system – and more importantly, no guarantee it will pass an MCERTS inspection. Ultimately, making the wrong choices can end up being a very costly mistake for your business.


How MCERTS flow measurement experts can help

We ask the right questions

There are several key questions we need to consider when installing part, or all, of an MCERTS flow measurement system:


  • Is the component suitable for the existing system? Understanding the type of flow measurement system is essential to choosing the right components. For example, a state-of-the-art electromagnetic flowmeter might sound like the best choice, but it’s not going to be very useful fitted in to an open channel drain or close to an aeration treatment plant and thus effected by entrained air.
  • Can the system be calibrated and future-proofed? If the existing system has been incorrectly installed from the start, new part isn’t going to solve the problem and we can’t effectively validate the system.
  • What is the nature of the discharge? We often get asked for a specific type of flow measurement, for example a V notch weir. However that isn’t a very effective method if the discharge contains significant solid content and can blind the V.
  • How has the flow measurement system been maintained? Poorly maintained equipment is one of the most common issues we encounter when visiting sites and is a leading cause of incorrect readings.
  • Is the flow measurement system suitable for your site? There is no one-size-fits-all solution when it comes to flow measurement. It’s essential to get a thorough understanding of the site the system is for to ensure it is fit for purpose. Factors such as available space, flow volumes and permit conditions are all important considerations.

We make sure your system is correctly calibrated

Regular flow meter calibration is essential for ensuring your device continues to provide accurate results. Not carrying out this vital process can result in your flow meter recording incorrect data and could result in a failed MCERTS inspection, or incorrect charging from your water utility provider.


When we install a new flow measurement system we always ensure it has been correctly calibrated. We also ensure that any flow measurement system we install has been designed to allow for future in-the-field calibration.

We guarantee MCERTS compliance

Choosing an MCERTS-accredited product doesn’t mean the flow system will automatically pass an MCERTS inspection.

We guarantee that any system we design, install, and maintain will be fully MCERTS-compliant – giving you the peace of mind that your system is providing accurate, cost-effective results and ensuring ongoing compliance with Environment Agency regulations.

We ensure the right data monitoring is in place

Data monitoring allows you to gather crucial flow meter data and ensure you are satisfying regulatory compliance for your water authority, as well as environment agencies in both England and Scotland.


Our cloud-based system offers a robust and reliable ‘plug-in and play’ option for wastewater flow monitoring using a specialist remote telemetry unit (RTU) and data visualisation suite, Palette.

Our bespoke Palette system allows you to monitor your effluent discharge from anywhere, at any time. Our cloud-based software gives you 24/7 access to your data, giving you the ability to get the information you need, whenever you need it.


Find out more about our data monitoring solutions.


For any queries or assistance with your flow measurement system, please contact our expert installations project team who will be able to offer you advice and support on choosing the right system for your site.


What is wastewater analysis?


What is wastewater analysis?

Wastewater sampling: what is measured and why?

The majority of businesses producing wastewater are required to carry out wastewater sampling to comply with their permit requirements.


Often this will be via self-monitoring, however companies may find themselves the subject of spot checks of their samples by the local water company to ascertain composition and volume of trade effluent produced. This supplied information is important as water companies use it to calculate final water treatment costs, using a method known as The Mogden Formula.

Wastewater analytes

What is being measured?

The full spectrum of analytes covered by MCERTS is listed in the Environment Agency standard Performance Standard for Organisations Undertaking Sampling and Chemical Testing of Water.

This is the standard businesses should refer to when implementing their effluent sampling processes as it details business requirements for the sampling and testing of trade effluent.

The most common analytes businesses are required to test by MCERTS are:

Physical properties

Physical properties analysed during wastewater testing include:

  • Temperature – Discharged consents are sometimes waived when the temperature drops below 4ºC so it’s important to conduct accurate temperature monitoring to avoid regulatory issues
  • pH – Monitoring acid/alkaline levels in water is important to ensure there is no impact on aquatic life. Even small changes to pH levels can have catastrophic results
  • Electrical conductivity (salinity) – Conductivity measures the ion capacity of liquids to carry electrical current. The reason we measure this is because higher conductivity generally means there is a higher ion concentration from dissolved salts
  • Turbidity – Turbidity refers to the clarity of the effluent. Although it is technically a measure of how cloudy the liquid is, often the particles are invisible to the naked eye which is why specialist equipment is required
  • Colour/odour – Hazen colour and odour checks can be an important verification tool to check against other physical properties  

Dissolved oxygen (DO) in water is essential to the survival of aquatic life.

In wastewater sampling, the BOD (biochemical oxygen demand) and COD (chemical oxygen demand) of effluent are measured to ensure water course DO levels will not be impacted by its discharge.


BOD measures the biological oxygen demand over a five-day period and equals the amount of dissolved oxygen required by organisms for aerobic decomposition of organic matter present in the water.


COD refers to the mass concentration of oxygen equivalent to a specified oxidant consumed by dissolved or suspended matter when a water sample is treated with that oxidant under defined conditions.


The level of solids in wastewater affect its quality and how it needs to be treated going forward.

Solids measurement differs from turbidity in that TSS measures the actual physical particles in the water (e.g. sediment) whereas turbidity measures the effect on light caused by particles. Solid measurement is split into:


  • TSS (total suspended solids) measures the dry weight of particles suspended (undissolved) in the sample. A high level of TSS allows water to absorb more light, increasing water temperature and reducing dissolved oxygen (DO), which can have a negative impact on aquatic life

  • TDS (total dissolved solids) – effluent with a high level of TDS can contain high concentrations of salts, making it unsuitable for irrigation or industrial reuse

An excess of nutrients in water contributes to algae overgrowth. 

Nutrient measurement is important as too much algae in water uses high amounts of nitrogen and phosphorus and results in the production of neurotoxins that are harmful to animals and may contaminate future drinking water.

Typically measured nutrients include:


Trade effluent from industrial processes is a primary source of heavy metal contamination.

Industries including textile, paper/pulp and metal finishing are all contributors, producing effluent that contains the “top four” toxic heavy metals arsenic (metalloid), cadmium, lead and mercury as well as chromium, nickel and zinc which are also toxic to humans and animals.

what is wastewater analysis sampler picture
What is wastewater analysis?


Next steps

The above list is not exhaustive, but contains some of the common analytes permit holders are required to be measured on. It may seem like an overwhelming task, but a good automatic wastewater sampler and associated monitors provide an accurate and user-friendly solution.

SIRIS offer a comprehensive range of MCERTS-approved wastewater samplers and analytical measurement tools designed to simplify the wastewater analysis process.  


For any queries or assistance with your trade effluent sampling or flow measurement, please contact our expert installations project team, who are set to help with any effluent challenge.


What is the Mogden Formula and why does it matter for trade effluent?


The Mogden Formula

Calculating Trade Effluent Charges

This rather complex-looking equation represents the key tool in calculating trade effluent charges.  Termed The Mogden Formula after first being adopted at the Mogden Water Works in London, it incorporates a number of variables such as contaminant and suspended solids levels that are used to calculate the final treatment cost per m3 of the effluent. 


The formula can be broken down as follows:


R = the charge from the water treatment works for receiving and conveying the effluent (in £/m3)


V = the charge from the water treatment works for the primary treatment* of the effluent *removal of material that will either float or readily settle out by gravity

(in £/m3)


Bv = the charge from the water treatment works for any biological* treatment (in £/m3) *breakdown/decomposition of organic contaminants from the wastewater


M = the charge from the water treatment works for the treatment and disposal of any effluent that must go out to sea (in £/m3)


B = the charge from the water treatment works for the biological oxidation* of any settled sewage (in £/m3) *B-stage, or bio-oxidation stage, where remaining organic material in low-loaded activated sludge is biodegraded


Ot = the chemical oxygen demand (COD) of effluent after one hour of quiescent settlement at pH 7 [mg/litre]


Os = the chemical oxygen demand (COD) of effluent after one hour of quiescent settlement [mg/litre]


S = the charge from the water treatment works for the treatment and disposal of the primary sewage sludge (in £/kg)


St = the total of suspended solids of effluent at pH7 (in mg/litre)


Ss = the total of suspended solids of effluent (in mg/litre)

what is the mogden formula

The more contaminants and suspended solids in the wastewater or effluent, the more expensive it will be to treat and dispose of.  This is known as The Trade Effluent Charge and is charged by the local water company to cover costs associated with the transportation, treatment and disposal of the effluent.


Many companies use water as part of their processing, such as produce cleaning or cooling, and understanding your Mogden formula can help identify areas to reduce wastewater processing charges.  Essentially there are two ways to do this:


–       Reduce the levels of contaminants/solids within the effluent

–       Reduce the volume of effluent

Water companies will issue licences of “Consent to discharge trade effluent” to those companies producing effluent for public disposal, which will outline specific conditions and charges for your licence.  The consent licence will stipulate how the wastewater must be monitored (or measured).  Sometimes this will be through self-monitoring but the water company may also routinely monitor flow and composition of the effluent to ensure compliance and estimate charges.   Water companies may vary in their application of the Mogden formula, but this information will be publicly displayed on their website, in line with the OFWAT regulator. 


Having an accurate and reliable picture of your effluent data is therefore key in ensuring the correct charges are being paid, as well as understanding where costs are coming from within the variables.  This is done via two primary methods – wastewater sampling and wastewater flow measurement. 

A Siris Effluent Sampler

Role of Effluent Sampling

An accurate base for calculations

Effluent sampling ensures the accurate measurement of those variables used within the Mogden formula.  Without them, calculations may be based on estimates, which could be bringing unnecessary additional charges to the business.

Investing in an approved, on-site wastewater sampling system gives more comprehensive and ongoing accurate data that can be used to monitor the quality of the wastewater discharge on a continual basis, using composite samples to provide data to the EA and local water authorities that can reduce charge liabilities and business costs.


At SIRIS we offer a range of MCERTS-accredited wastewater samplers that suit both open channel and closed pipe applications, providing robust and long-lasting sampling solutions for a range of industrial and commercial businesses.  We offer automatic, composite, refrigerated sampling, which ensures regular samples of your effluent at key times e.g. high loads/low loads.  Factors such as this are important and carefully considered in the design and specification of your effluent monitoring system by the SIRIS team.  For example, water company spot samples may focus on times of high contaminant concentration, giving an inaccurate picture of the average effluent strength level and causing unnecessary charges.  The refrigerated element of our samplers ensures that samples do not degrade.,


Role of Flow Measurement

Ensure a true picture of volume of effluent


Measurement of volume of flow is another critical data point in which to ensure accuracy.  Again, on-the-spot water company measurements can give biased flow volumes, for example if these were taken only during high production points on the plant. 


Our solutions ensure an accurate picture of flow volume over time.  Depending on the specific business type and requirements, effluent flow may be measured on either an instantaneous or continuous basis, each of which requires careful specification of equipment. At SIRIS, our experienced approach to effluent flow measurement allows us to specify and develop robust and reliable measurement systems.

MCERTS Certification
Learn how we saved one client over £170,000 through accurate effluent monitoring


For any queries or assistance with your trade effluent sampling or flow measurement, please contact our expert installations project team, who are set to help with any effluent challenge.


Proud to be supply chain partner of award-winning Wolsingham Sewage Treatment Works Growth Improvement Project

SIRIS proud to be supply chain partner of award-winning Wolsingham Sewage Treatment Works Growth Improvement Project

The whole projects team at SIRIS is proud to have been a recognised supply chain partner in the award-winning Wolsingham Sewage Treatment Works (STW) Growth Improvement Project.  Completed in 2021 during the height of the pandemic, the £6m project has been awarded Civils Project of the Year in the Constructing Excellence in the North East Awards.

Led by Tilbury Douglas (contractor) and Wood (designer) for client Northumbrian Water, the project was recognised for its use of new technology, implementation of off-site, sustainable construction methods and best-in-class collaboration between all project stakeholders


The Project

An upgrade to tackle increased flows and asset deterioration

The Sewage Treatment Works was in need of an upgrade as demand on the site had increased in line with population growth in the area, estimated at some 19%.  The upgrade project had to identify solutions to the issues caused by increased flows and loads identified at the site and the related impacts on associated sewerage networks.  In addition to this, further work to tackle asset deterioration and ongoing pollution incidents due to sewer overflow was to be incorporated into the project. 


The design phase of the project, started in 2018, took an innovative “Off-site by Default” and DfMA (Design for Manufacture and Assembly) approach to build technology, an ethos that was mirrored throughout all phases of the project with the ongoing support of client Northumbrian Water.  The Sewage Treatment Works was consequently able to be built using off-site build methodology, a ground-breaking approach within the water industry. 

This method brought tangible and sizeable benefits to the project in terms of reduced costs, timelines and environmental impact; with some £1m pounds, 4 months and 34 man hours estimated to have been removed from the project initial budgets and timescales. 


Northumbrian Water now plans to adopt the new off-site build approach within their AMP7 framework, a real testament to the success of the project and the collaboration of partners and supply chain throughout. 

Picture courtesy of Tilbury Douglas
Early phase drawing of the inlet flume design The inlet flume, manufactured off-site and installed into the inlet works Picture courtesy of Wood https://www.woodplc.com/
Add Your Heading Text Here


Off-site Build Concepts

Working under the brief of design partners, Wood, SIRIS was able to develop off-site build concepts for the inlet of the works, using a prefabricated, above-ground approach.  The inlet-flume design was built offsite within the SIRIS on-site factory, using non-standard GRP-reinforced, welded PVE construction materials to give the increased accuracy and sensitive tolerances expected for MCERTS certification.  The materials also benefited from a service life of up to 50 years.    

Transported in two sections, the inlet flume was installed readily into the SWT without problem, showing the potential for future off-site build methods for installations of this type.



“The off-site construction nature of this project represented a new approach in the water industry.  With our on-site factory and engineering team, we were able to quickly integrate into the adopted working methods by providing a fully constructed inlet flume and weir system, then transported to and installed on the works site directly.  Our team collaborated fearlessly with the project team to achieve all requirements and we are proud to have been involved in such an innovative development.”

Here at SIRIS we are able to work with our clients flexibly and in line with individual project requirements.

Working with varying client types, including water companies and trade customers, we design, construct and install reliable and accurate flow measurement and sampling installations for use with trade effluent and wastewater.

SIRIS supports Yorkshire Water and BarhaleDoosan JV in trial of first nature-based wastewater treatment plant.

 A trial of a sustainable wastewater treatment system is underway at the Yorkshire Water Clifton works, where over 20,000 wetland plants utilising the natural clay are being used to remove phosphorous from the wastewater as a natural alternative to traditional, energy-heavy chemical treatment.

The successful trial of the project will pave the way for further low-carbon, sustainable clay and wetland treatment plants, which aim to reduce energy and chemical usage, as well as create wildlife diversity including bees, breeding birds, amphibians and reptiles.
Further sites have already been identified across the Yorkshire region and results will be closely monitored for potential roll-out.

Flow Monitoring Solutions Provided by SIRIS


Working alongside design partner Stantec, BarhaleDoosan JV was the project partner tasked with construction of the site and engaged SIRIS to provide monitoring solutions to deliver key data on the flow of wastewater through the plant. 


With the trial being closely monitored by both project partners and the Environmental Agency, the MCERTS-approved, wastewater flowmeters are providing important data to gauge wastewater evaporation and flow leakage rates between inlet and outlet points at each end of the 5x 800m3 plant cells.  The flow meter system includes a battery powered cloud-based telemetry, meaning information is accessible for project stakeholders.



A high level of evaporation or flow leakage would mean that plants within the marshland would not receive the required nutrients required for their long-term survival and lead to unacceptable levels of phosphorous and BOD in the final wastewater output.


Important to the project for BarhaleDoosan JV was to maintain a low carbon footprint across the whole project, including design and build processes.  The easy-to-maintain open channel flow meters were designed to include a solar panel, which not only makes them highly energy-efficient, but removed the need for installation of over 200m of cable ducts and electric cables, concrete-heavy draw pits and associated deliveries of materials.  





The level of support from the team at SIRIS was outstanding.  They were very approachable, knowledgeable and fully engaged when considering all options to meet our project aims, coming back with well-thought-out and cost-efficient solutions.

Mollie Geoghegan
Engineering Design Manager, Barhale Doosan JV



The team at SIRIS is also excited to see the results from the trial.  General Manager Karl Bambynek said,



“The project is a milestone in bringing sustainability within the wastewater treatment industry and we are proud to be involved in its delivery. If successful we could see significant roll-out and an important positive impact on the environment and its levels of biodiversity.  We are pleased that our flowmeter systems can play a part and look forward to following the project’s progress.”



Guide to: getting ready for your MCERTS inspection

Preparing for your MCERTS inspection might seem daunting – even if you’re used to the process. In this guide, we’ll be explaining the steps you need to take to get your site ready for a successful MCERTS inspection. 


What are the steps to obtaining MCERTS compliance?


The first step to achieving MCERTS compliance is obtaining a consent to discharge permit. This is a legal requirement for most businesses discharging trade effluent to a public waterway or sewage system – although there are some exceptions.


You can learn more about obtaining a consent to discharge permit here.


There are then three stages to getting certified:


1. Inspection: A certified MCERTS inspector will visit your site to inspect your flow measurement system. Provided the installation meets the standards, the inspector will issue a conformance report.


2. Audit: An independant auditor will inspect your QMS (Quality Management System) to make sure it meets performance requirements. If it does, you will be issued with a conformance report.


3. Certification: Provided you have passed the inspection and audit, you will be issued with an MCERTS certificate. Certification is valid for five years after which the installation is re-inspected. The QMS is subject to periodic surveillance audits during the five-year period.

MCERTS certification process


You can view the status of your MCERTS certification through the CSA Group’s Certificate Database, which shows whether a certificate is still current or has been withdrawn or suspended.



Getting ready for your MCERTS inspection

The following steps are our recommendations for preparing for your MCERTS inspection. Whether it’s your first inspection or a re-inspection, it’s a good idea to go through these steps to give your site the best chance of a positive outcome.


1.Familiarise yourself with the latest MCERTS compliance guidance. It’s a good idea to get up-to-date with the Environment Agency’s latest MCERTS performance standards and conduct an internal audit to highlight any areas of concern ahead of the inspection.


2. Make sure the inspector will be able to access the site. Please ensure any necessary paperwork to allow our team access has been completed ahead our visit and let us know about any training or ID requirements, as well as any site-specific risks.


3. Ensure there will be a qualified team member on site. It’s a good idea to make sure that whoever is on site to welcome the inspector has a good working knowledge of the system and is able to answer any questions.


4. Get your paperwork ready. The inspector will need to see a copy of your Consent to Discharge and/or permit, along with maintenance and calibration records.


5. Collate any representative flow data you have to hand, or make Cloud data available to the inspector. The inspector will typically need to see a 15 minute spot average and daily volumes. This will help them understand the site’s discharge pattern and any variations in flow rate and will be useful if there are unusual flow levels on the day of inspection.


6. Check your maintenance programme. Poorly maintained equipment can cause flow meters to give incorrect readings. Your flow system should be in good condition and well maintained and we will need to check maintenance records to asses how effective your maintenance programme is.


7. Make sure the flow meter display unit is accessible. The inspector will need to see the make/model, connect a laptop to download the data, and possibly interrogate settings to ensure correct set-up.


8. Check the location of the flow meter. Our inspector will need to carry out detailed checks, a flow test. Please make us aware in plenty of time if there are any specialist requirements such as confined space entry. Remember, we may need to access the flow channel and/or isolate the flow.


You can download a printable copy of these steps here.


How Cloud data can help

Our remote data monitoring system makes it much simpler to prepare for your MCERTS inspection. Using our specialist specialist remote telemetry unit and data visualisation software, our inspectors can quickly access real-time data from your monitoring system. With 24/7 remote access to your data, investing in a data monitoring component for your flow measurement system saves time and money. What’s more, you can focus on getting ready for inspection without panicking about paperwork!


Find out more about how data monitoring can help your business.


Get in touch to talk about your MCERTS inspection


Our MCERTS inspection team

At SIRIS, our team of MCERTS experts are always on hand to offer support and guidance.


Get in touch to find out more about MCERTS or preparing your site ready for inspection.


Useful links

Meet the experts: Jordan Marley


We’d like to introduce you to the experts who make up our team here at SIRIS. This month we’re talking to Trainee Servicing & Installation Engineer, Jordan Marley.


What is your background and how did you start working at SIRIS?

I left school with better grades than I was expecting and as a result was able to do an electrical engineering course at Sunderland College. Towards the end of the year I had already gained two of the three available qualifications and to get the third I needed to do a week of work experience with an engineering company. Most companies looked the same but one that stood out was SIRIS so I asked my tutor to contact them and see if they’d be willing to offer me a placement which they did! I spent my week learning the ins and outs of what SIRIS do and even got to go on my first ever site visit. The end of the week came, and I’d thoroughly enjoyed my time with the company, so you can imagine how pleased I was a few weeks later when I received a call from Nick offering me a job!


My first day was 17/07/17 and almost four years later, I’m still here, still learning and of course still enjoying my work.


What does a typical day look like at SIRIS for you?

No two days are ever the same. One day I could be in the workshop building, assembling and programming a flow system to be delivered to a site, and the next I could be on the road travelling to sites all over the country calibrating, servicing and verifying equipment that we have provided them with. I really like the variety and it keeps work enjoyable and interesting.


What do you enjoy most about your job?

I love to solve problems! There’s nothing better than visiting a site where a customer is having issues and finding a solution for them, it gives me a huge sense of pride when I’m able to help others out (and of course relief).


What’s a favourite project you’ve worked on recently?

I recently carried out an electromagnetic flow meter installation with fellow engineer Lee Smith for a water company. It was a really challenging job as we had to remove the old broken flow meter and then refit the one into an extremely deep and, as you can imagine, not very spacious, confined space. It was tough and it took us all day to do, so it was really satisfying to see when the flow reading showed up on the transmitter. A challenging, but great day’s work.


What do you get up to outside of SIRIS?

I’m an avid Sunderland supporter and have been a season card holder for more than 10 years now (someone’s got to do it!)


I’ve only been to one game in the last year and a half due to the pandemic so I’m really looking forward to next season when I can hopefully get back to the Stadium of Light. I’m currently missing the feeling of coming in on a Monday morning when Sunderland have won and Newcastle, who Karl supports, have lost. Other than this I love to travel and spend time with my family and friends.