From a small metal walkway above the Minworth sewage treatment plant, the smell is unmistakable—a grim wave of odour rising from the murky brown water flowing in from Birmingham and the Black Country. This massive facility handles sewage for 1.8 million people, processing an average of 6,500 litres per second. After recent heavy rains, that volume has surged to 9,000 litres per second.
As the wastewater moves towards metal screens designed to filter out debris, next to them lies a greyish-brown mound that reveals a growing problem. Each day, Severn Trent Water (STW) extracts around 15 tonnes of “rag” – a mixture of baby wipes, sanitary products, and other items improperly flushed down toilets – which are then sent to landfill. This material clogs pipes and drains, causing serious blockages and flooding that impact homes and communities.
Grant Mitchell, blockage lead at STW, warns, “It seems easy to chuck things down the toilet, but you’ll risk flooding your own property. Many don’t realise sewer pipes are only about the size of a toilet roll.” Senior technician Philip Powell, with 44 years at STW, confirms, “When I first started, rag was hardly an issue. Now, it’s everywhere.”
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The debris found is often bizarre—a mix of condoms, goalkeeper gloves, even dead rats. Over the years, STW has recovered unusual items including parts of a horse carcass, weapons passed to police, motorbike parts, lorry tyres, a Christmas tree, a shed, and children’s toys flushed accidentally.
Blockages aren’t just an eyesore; they cause around 30,000 incidents annually across the West Midlands, frequently leading to expensive repairs for homeowners and significant environmental damage. Roads and recreational spaces often flood, disrupting daily life.
Another significant culprit is ‘FOG’—fats, oils, and grease—which solidify into fatbergs inside pipes, especially problematic given the density of fast-food outlets in Birmingham. “Every high street has at least one,” notes Philip. STW works closely with 11,000 food service establishments each year to enforce laws preventing FOG from entering sewers. Measures include advice and prosecutions, sometimes resulting in court cases.
Grant emphasizes that grease traps are a practical defense against fatbergs. While not legally mandatory, these devices collect FOG before it reaches sewers, fulfilling legal obligations for businesses to prevent discharge. There’s also a financial upside: collected FOG can be converted into biofuel—an approach McDonald’s uses to power its trucks.
Households are also urged to avoid pouring fats and oils down drains to help reduce blockages.
Minworth plant itself spans seven miles and is one of Europe’s largest sewage treatment sites. At the far end, enormous circular pools purify wastewater to levels cleaner than the receiving river. Besides removing rag and debris, STW recycles grit, fat, and even transforms sewage sludge into fertiliser, making the process environmentally sustainable.
The key message from STW is simple: follow the ‘three Ps’ rule—flush only poo, paper, and pee. Anything else belongs in the bin, not the bowl.