Sewage Odour Control: A Brief History

Before we dive into the latest innovations in sewage odour control, it’s worth taking a short step back in time. A little diversion from our usual focus, this piece is a quick journey through the history of sewage treatment, from one of the most infamous smell-related crises in history to the modern, enzyme-based odour control solutions.

The Great Stink

In the summer of 1858, London faced a crisis that was impossible to ignore. A booming population, and the absence of effective waste treatment created a perfect storm. The River Thames, the city’s main waterway and open sewer, reeked so badly that Parliament had to suspend sessions. Newspapers dubbed it The Great Stink, and the event spurred a turning point in public health and urban engineering.

Bazalgette’s Sewer Revolution

The public outcry led to the appointment of Sir Joseph Bazalgette, who designed an ambitious network of intercepting sewers, pumping stations, and outfalls. Completed in the 1870s, this Victorian feat of engineering diverted sewage away from drinking water supplies and drastically reduced cholera outbreaks.

Birth of Modern Sewerage

Bazalgette’s achievement was monumental, but early systems mainly focused on transporting waste, not treating it. In the decades that followed, sewage treatment moved beyond simple removal. Settling tanks were introduced to allow solids to drop out before discharge. By mid-century, chemical disinfection such as chlorination became standard. While effective in the short term, these approaches often involved high costs, potential environmental impacts, and ongoing chemical handling.

The Problem of Odour

Even with modern treatment, odours remained a persistent challenge. Hydrogen sulphide (H₂S), mercaptans, and volatile fatty acids are by-products of anaerobic decomposition in sewers and treatment tanks. Left unchecked, they caused complaints from nearby communities, corroded infrastructure, and created hazardous working conditions.

Enzymes: A Biological Breakthrough in Odour Control

In recent decades, enzyme-based solutions have emerged as a more sustainable and targeted method for odour management. Enzymes are biological catalysts — proteins that speed up chemical reactions. In wastewater odour control, they target and break down the specific organic compounds that feed odour-causing bacteria. For example:

• Protease breaks down proteins into peptides and amino acids, reducing the substrates for sulphide-producing bacteria.

• Lipase degrades fats and oils, which can trap odorous compounds.

• Amylase breaks down starches, reducing fermentable materials.

Enzymes work efficiently in small doses, leave no harmful residues, and help protect sewer infrastructure from corrosion — all while keeping the air around treatment works far more pleasant.

From Victorian Sewers to Sustainable Solutions

The Great Stink forced society to confront the consequences of neglecting waste management. Bazalgette’s Victorian engineering marvels laid the foundation for modern sewage treatment, but the story didn’t end there. Today, the push is not only to treat waste safely but to do so in ways that minimise environmental impact and improve community well-being.

Enzymes, nature’s own catalysts, are now helping to write the next chapter — tackling odours at their source, reducing chemical dependency, and making wastewater treatment cleaner and greener.