Water treatment to eliminate cyanobacteria and other toxins by unmanned surface vehicles (USVs)
Freshwater resources around the world are under stress due to naturally occurring events and human impacts, causing an increase in cyanobacteria blooms. These cyanobacteria release harmful toxins, known as cyanotoxins. The proposed USV degrades the toxins on-site with UV light, reducing the accumulation of toxins, preventing groundwater contamination, and improving water quality.
Treatment of cyanobacteria and cyanotoxins is necessary before they reach a critical point, or they can contaminate other environments. For example, waste produced by water treatment facilities serves as fertilizer for agricultural land, and if not properly treated, toxic cyanobacteria can grow in the soil followed by uptake into plants. Because of this, it is crucial to treat wastewater properly. Wastewater needs three subsequent treatments before water reuse, recycling, or release back into the environment. The tertiary treatment involves removing microorganisms from the water, as certain ones are pathogenic for humans. Typically, chlorination is this tertiary step, but this method is inherently hazardous and can create toxic by-products. Instead, UV disinfection is becoming more common for treating wastewater, as it does not produce harmful byproducts or hazardous material concerns. Current UV treatment systems may need retrofitting to an existing wastewater treatment plant or building a completely new system, and both processes can be costly.
Environmental scientists at The Ohio State University have developed a USV equipped with UV-C lights that acts as an on-site treatment for toxic cyanobacteria blooms. Since the cyanobacteria blooms rise to the water surface, having a USV running along the surface can treat the cyanobacteria where they naturally accumulate. The device is cost effective, as once built it requires no input costs. Cyanobacterial blooms increased drinking water treatment costs by ~$13 million in Ohio alone in 2011–2012. With the blooms under control, the proposed technology could help reduce water treatment costs. This device has the potential to become a new standard in water management practices, because it can increase sustainability, create safe use of sludge for the agricultural industry, and protect the ecosystem and public health.
Provisional patent application filed.