Effective wastewater treatment may underpin the efficiency of a whole industrial site and with the disruption wrought by Covid-19, planning and maintenance is more essential than ever, says Andrew Baird, WPL’s technical director.

Until a vaccine is developed and rolled out there is a strong likelihood that there will be global resurgences of Covid-19. For industry, this means ensuring resilience through periods of intermittent lockdown, staff absence and a scaled-back workforce.

For businesses with onsite wastewater treatment, this reinforces the need to have reliable processes in place to ensure the plant continues to operate effectively and within consent, even during the most disruptive circumstances. Before the pandemic, the Environment Agency made clear to the water industry its expectations for zero pollutions, with its toughening approach to discharge permit breaches leading to a number of high-profile prosecutions and record fines.

While much of the Agency’s scrutiny had been directed at the water sector, in 2019 it told the industry to clean up its act and protect the environment. All companies with onsite treatment should be reviewing processes to avoid pollutions and potentially serious penalties.

WPL specialises in packaged wastewater treatment plants and sees different companies making the same avoidable mistakes that result in permit breaches – but the solutions are often simple:

Champion the equipment

When it comes to commercial or industrial companies, onsite effluent treatment is not necessarily seen as a core part of the operation and interest can be lacking. This can result in this vital equipment, that may underpin the efficiency of the whole site, being some of the least loved, leading to process faults or mechanical breakdowns.

Equipment failure lies behind the majority of permit breaches and pollutions, and often occurs due to a lack of maintenance. When installing new kit, we advise management to give the responsibility of maintaining it to specific employees who understand not only the mechanics, but also the importance of the plant.

In addition, there must be an understanding that the effluent coming into the plant from industrial operations will vary and this critical equipment must be regularly monitored and adjusted to effectively treat the incoming flows.

Having enthusiastic champions of the equipment means it is more likely to receive the attention it deserves. It is now vital to assign these responsibilities to a team, rather than an individual, so the knowledge is not lost if one person is absent.

Monitor carefully and remotely

Close and careful monitoring of the plant will have an increasingly important role to play. With the extra pressure now on companies to meet their consents, it is prudent to have a reliable system in place to provide early warnings of any mechanical faults or process issues.

Technology is available to alert users by sending text messages to mobile devices or via email, allowing for management to be alerted while off-site, while also alerting the onsite workforce.

Monitoring is site-specific but can include:

Flow monitoring – designed to measure and display the flow rate of discharged final effluent from wastewater treatment plants. A large portion of plant failures happen simply because production has expanded and the system is just too small.

Turbidity – almost every site in the UK will have a consent permit regarding solids. Turbidity can monitor solids from any part of the process. You may have a delicate biological treatment that is sensitive to solids or a strict consent standard. Monitoring can alert to plant failures early.

Upskill staff

The biological wastewater systems that WPL designs, such as the Hybrid-SAF, are simple, robust and require low maintenance – the simpler the system, the less chance there is of it failing consent.  However, the importance of this equipment cannot be overstated, and the need for ongoing training for a team of personnel in how to operate and maintain it is essential.

Training will go a long way in preventing equipment and processes breaking down and ensuring the treatment plant remains fully compliant and continues to protect the environment. It can also help drive energy – and cost-saving efficiencies.

Recommission safely

Covid-19 has also highlighted the need for businesses to understand how to safely decommission and recommission their onsite treatment plants.  Sites that are likely to experience sudden drops in throughput, or complete closure, such as hospitality and leisure facilities, or manufacturers of non-essential items, must be aware of the importance of this process and the risks of not carrying out commissioning procedures correctly.

WPL treatment plants are designed to take a minimum flow of 10% of capacity. If a venue that would usually have 2,000 people contributing to the organic flows into the plant now has just 20 people, that is well below the minimum amount needed to keep the biological treatment process ticking over.

If the plant has remained operational and some of the flow has been maintained, it is likely to take up to two weeks before the plant will pick back up to treat high volumes effectively. If the plant has been turned off completely, it can take up to six weeks for the biological process to embed.

With reduced flow may also come a change in composition of final effluent. Checks should be made to check concentration of final effluent so the treatment process can be adjusted accordingly.

Be cautious in your approach and seek advice from the equipment manufacturer or supplier to ensure the site can continue to treat wastewater to the required standards when returning to business as usual.