Red Sea bacteria recruited to boost the use of saltwater toilets
Given the current scarcity of clean, fresh water in many regions, it does seem kind of crazy to be flushing the stuff down the toilet. And while a few coastal areas use seawater instead, doing so is problematic in its own way – new research, however, may change that.
Ordinarily, when the fresh water that's been used to flush toilets reaches sewage treatment plants, granules containing two types of bacteria are used to remove the nitrogen from it. Along with various other processes, this helps to clean the water up, so it produces a minimum of pollution when introduced back into waterways such as rivers or the ocean.
Unfortunately, one of the two microbe types – known as an anaerobic ammonium oxidation bacteria – has a very low tolerance for salt water. As a result, it's quite ineffective at removing the nitrogen from seawater sewage. This is one of the main reasons that such water isn't more commonly used to flush toilets.
Headed up by postdoctoral fellow Muhammad Ali and PhD candidate Dario Rangel Shaw, a team at Saudi Arabia's King Abdullah University of Science and Technology (KAUST) cultured a different bacterium from the Red Sea. It's called Candidatus Scalindua sp. AMX11, and their lab tests have shown it to be about 90 percent effective at removing nitrogen from a nitrogen-rich seawater solution.
"The findings demonstrate a proof of concept, and the next step is to demonstrate this technology in a microbial granular system containing Candidatus Scalindua sp. AMX11 bacteria and the other types of bacteria necessary for a full-scale wastewater treatment process," says the team leader, Assoc. Prof. Pascal Saikaly.
The study is described in a paper that was recently published in the journal Water Research.