Concerns over harmful caravan toilet chemicals

South Australia's Flinders University has raised concerns over the potential harm caused by some caravan toilet chemicals that end up in regional wastewater systems.

Flinders University researchers focused on whether caravan toilet chemicals such as bronopol, a powerful disinfectant chemical, may disrupt wastewater treatment microbes.

"When people using caravans empty their toilet waste at roadside dumpsites, caravan parks and regional dump stations, the wastewater – which contains concentrated detergent, deodoriser and sanitiser chemicals – is transported to local wastewater treatment plants," the university said on its website.

“While these products help maintain hygiene inside caravans, the chemicals may interfere with the beneficial microbes used in wastewater treatment systems."

A research survey of 160 Australian caravan users found that most used chemical toilet additives; many of which contained bronopol, a disinfecting chemical that can break down into formaldehyde and other potentially harmful compounds.

“The findings highlight a growing challenge for regional towns that manage caravan wastewater,” one of the researchers said. “Regional wastewater plants are often smaller and designed mainly for household wastewater, but caravan toilet wastewater is much more concentrated and can contain high levels of disinfectants and other chemicals.

“Given that bronopol can degrade into persistent and toxic by-products, including formaldehyde, 2-bromo-2- nitroethanol, and related nitro-alkane derivatives, these antimicrobial compounds may inhibit microbial communities critical to primary treatment processes in regional soakage pits and septic tanks.”

This could become a bigger issue during peak holiday periods, affecting "nearby environments if wastewater is not properly treated".

The study found around two-thirds of caravan users routinely use DDS products and while most follow the recommended dosage instructions, bronopol-based products were the most popular choice.

Research co-author Professor Kirstin Ross said the findings can help regional councils and wastewater operators better prepare for increasing caravan-based tourism.

“Understanding what chemicals are entering wastewater systems is important for protecting public health, wastewater infrastructure and the environment,” she said.

The research team said further studies are needed to better understand how caravan toilet chemicals behave in wastewater systems and how treatment plants can adapt to increasing tourism pressures.

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