How to satisfy MCERTS requirements for effluent self-monitoring using flowmeters

Industrial companies account for a significant proportion of water and energy consumption in the UK. These companies produce considerable volumes of waste, which need to be accurately monitored in order to assess and limit their impact on the environment.

How to satisfy MCERTS requirements for effluent self-monitoring using flowmeters

Under the Environmental Permitting Regulations (EPR), all industrial companies discharging 50m3 or more of effluent per day to a watercourse or the sea have an obligation to self-monitor their effluent flows. Some companies that discharge to a particularly sensitive aquatic life area may have to self monitor their effluent flows even if they are discharging below 50m3 per day. In these cases this would be specified in their EPR permit.

Introduced as part of a move to improve the measurement and control of discharge and waste levels from industrial companies, the self-monitoring obligation requires operators to comply with the Environment Agency's MCerts certification scheme. Under this scheme, companies should be able to demonstrate to the satisfaction of an MCerts inspector that they are using the Best Available Technique (BAT) to protect the environment. Where the self-monitoring of effluent flow is concerned, operators are subject to a ±8% uncertainty target for the measurement of total daily volume of effluent discharged. This covers not just the equipment used, but also other factors such as correct fitting and the training of relevant personnel to ensure that an installation is correctly set up, operated and maintained.

In practice this means that, if there are instruments or systems using a particular technology that have passed all the necessary tests and received an MCerts compliance certificate, operators must use them.

This requirement does not necessarily apply if there is an alternative technique available that can outperform the MCertified instruments for specific applications. There may not be any MCerts-approved examples of the superior technology, but the regulator will usually be happy for companies to use it because it constitutes BAT. This scenario is naturally going to crop up more in the early days of the scheme, because it takes time for instrument manufacturers to get their products approved.

This is precisely what's happening right now in the self-monitoring of effluent discharge. The few MCerts-approved metering systems listed so far rely on open channel flow or clamp-on ultrasonics, but everyone knows that closed pipe magnetic flow meters offer a demonstrable improvement in metering accuracy when compared to these technologies. MCerts inspectors are therefore happy to approve monitoring installations that rely on magnetic flow meters from reputable suppliers as they stand a much better chance of achieving the ±8% uncertainty target for total daily effluent volume.

ABB is one of the companies that has gone through the MCerts approvals process for its electromagnetic WaterMaster and MagMaster meters. Once there are one or more magnetic flow meters available with MCerts approval, companies will be obliged to use them, rather than opting for unlisted competing products using the same technology.

The requirements do not just cover equipment, however. Operators must also prove that they are capable of managing their own effluent self-monitoring. This requires them to have their sites inspected by an MCerts inspector every five years and to undergo an audit of the Quality Management Systems (QMS) relating to their flow monitoring arrangements.

Meeting the MCerts uncertainty target of ±8% for effluent flow monitoring could also help many operators to become more cost effective. Many flow metering installations will be inaccurate if they are not properly installed and maintained. If they measure excess effluent as a result, operators will be paying too much for their waste disposal. Incorrect flow measurement may also have a knock-on effect on other areas such as pumping costs, which is increasingly important in light of today's high energy prices.

Once a site has been approved by an MCerts inspector, the resulting certification will be good for the next five years, although the site's QMS will continue to be audited on an ongoing basis, with the frequency of surveillance audits determined by the level of competence shown by the operator. It is therefore a good idea for operators to ensure the continued accuracy of their effluent self-monitoring equipment to eliminate the risk of a breach in their permit conditions.

Many companies will have established a formal environmental management system to demonstrate compliance with their permits, perhaps working to a standard such as ISO14001. But whatever procedures companies have in place, there is an old truism that applies here: you cannot control what you cannot measure.

Meter verification using in-situ verification tools like ABB's CalMaster2 is a step in the right direction towards demonstrating a sound flow measurement system. Correct installation of equipment such as flow meters is also an important factor and users should adhere to manufacturers' recommendations for upstream and downstream straight pipe lengths and correct earth bonding. Competent Manufacturer's Verification Engineers are best equipped and trained to provide this ongoing support. With CalMaster2, printed verification certificates complete with accuracy statement is also provided for the operators QMS records.

Compliance can be difficult, but there is help available for companies that do not want to fall foul of the law. Manufacturers going through the MCertification process, such as ABB, will be able to advise companies on how to comply and stay compliant. Alternatively, visit the Environment Agency's website at for more advice.

Many companies regard the new regulatory regime as onerous, but they need to remember that the aim of the Environment Agency is to protect the environment, not to catch businesses out. The increased emphasis on operators taking responsibility for monitoring and controlling their own emissions may require some investment in new instrumentation, regular verification, robust maintenance regimes and monitoring equipment, but it will be for everybody's benefit in the long run.

N.B. The information contained in this entry is provided by the above supplier, and does not necessarily reflect the views and opinions of the publisher