What is industrial wastewater treatment - and who needs it?
The management of wastewater is highly regulated in the UK, with most modern treatment plants operating according to strict health & safety and environmental standards. Over decades, this has meant we have not had to think much about what happens to the wastewater we produce once it leaves our homes and places of work.
But this is now changing.
Why wastewater disposal became a hot topic
Water quality is now a topic being debated on doorsteps, online, in parliament and across the media, with unprecedented levels of scrutiny on the performance of utilities and corporate companies whose operations can impact their local environment. As a consequence, more and more companies are facing rising wastewater discharge consent costs and community challenges to their working practices.
How does wastewater affect the environment?
Every week we see new stories emerge about the consequence of untreated or unauthorised trade effluent releases on the environment. These accidents can cause serious damage to the natural world and the sewage infrastructure as a whole. Toxic, chemical waste can kill fish and waterfowl, while even organic waste can clog up pipes and upset the delicate balance of natural ecosystems when released untreated.
Who needs industrial wastewater treatment facilities?
As the food and beverage sector and other industrial water users respond to intensifying environmental concerns, they need to ensure that their wastewater treatment systems are effectively delivering the required levels of water quality and compliance.
The wastewater produced by the food and beverage sector contains large quantities of contaminants, including fat, oil and grease, and has high biochemical and chemical oxygen demands (BOD/COD). Wastewater streams can be complex and highly variable and must be treated and disposed of according to strict regulated standards.
This means treating it to levels that will not damage receiving waters or harm wildlife if directly discharged into the environment, or will not disrupt the local treatment works if discharged to sewers as trade effluent.
Trade effluent consents
For water engineering specialists, a key part of the day job is addressing industrial clients’ potential issues with their water companies over trade effluent consents. Given the demand on utilities to tighten up their operations, industrial water users can expect to feel continuing pressure to keep their houses – or treatment processes - in order.
They risk significant fines or prosecutions, as well as corporate, reputational risk, if they do breach consents. This should be a major consideration, especially for sensitive public-facing brands.
But the good news is advanced treatment processes can ensure that any final effluent – whatever your business produces – meets all required standards.
What are the three stages of industrial wastewater treatment?
The wastewater treatment process has three stages - primary, secondary and tertiary - each targeting specific pollutant types.
This involves the physical removal of large solids and some organic matter. It typically involves processes such as screening, grit removal and sedimentation. Screening removes large objects and debris; grit removal eliminates heavier inorganic particles; and sedimentation, using equipment such as lamellas or settlement tanks, allows for the settling of suspended solids resulting in the formation of primary sludge. The addition of specific coagulants or flocculants – chemicals that remove suspended solids and other impurities - can vastly improve treatment efficiency at the primary and subsequent stages.
This stage focuses on the removal of dissolved and suspended organic matter using biological processes. Common methods include activated sludge, trickling filters, and other biological reactors. The use of nutrient chemicals to improve biological growth and settlement in the secondary phase can further enhance effluent quality. Microorganisms break down the organic compounds, reducing BOD and further clarifying the wastewater.
This is an advanced stage that aims to further polish the effluent to meet specific water quality standards by removing any remaining contaminants and fine suspended particles. Dissolved air flotation (DAF) is a popular clarifying treatment technology that concentrates and removes a wide range of suspended solids, oil and grease. Others include filtration, such as use of sand filters, disinfection and biological nutrient removal.
Trade effluent and the circular economy
Dewatering is the post-treatment process of removing liquid from sludge to reduce its weight and volume prior to disposal. A screw press applies pressure to the sludge, squeezing the water out via a filtration system and is simple, sustainable and cost-effective.
The separated liquid continues through the plant’s treatment process, and can be discharged into the public sewer, in line with trade effluent rules, or recycled and reused. The remaining, dry solid waste, known as cake, can be safely stacked and transported by lorry to an anaerobic digester where it is used to produce biogas and biofertiliser. Separating out valuable resources in this way takes a circular economy approach that can even generate revenue, while also reducing the need for costly tankering and reducing the number of journeys required, along with carbon footprint.
The climate emergency and companies’ own sustainability pledges, mean many brands are keen to embed more eco-friendly practices - water technology companies are working with more and more clients keen to close the loop on wastewater. Similarly, innovative technologies are emerging to promote the reuse of treated wastewater for purposes in a variety of industrial and agricultural applications, reducing the strain on freshwater resources.
Hire and trial
The option to hire and trial WCSEE equipment before purchasing means compliance is achieved quickly, without a capital expenditure commitment. Businesses can then conduct a full-scale operational trial, with sampling and laboratory testing of effluent, to build a case for capital funds and ensure the correct long-term processes are installed.
Topics: Wastewater Treatment
Written by Pete Cranney
Pete Cranney has worked for Atana (now part of WCSEE) since 2003 and has experience across every part of the business. Specialising in food & drink manufacturing, Pete can recommend the most practical and cost-effective treatment processes, designing onsite solutions that achieve strict discharge consents. In previous roles, Pete has managed full treatment plants for clients such as PepsiCo and Kraft Heinz. He has also led on laboratory testing of client samples. In process design, Pete provides clients with the most effective blends of chemical and mechanical treatments to ensure their sites offer full environmental protection 24/7.