Scientists are using new methods to creatively produce fuel and electricity, but they can also cause their own problems,media reported. For example, the use of algae to make biofuels shows promise, but it does produce a lot of toxic wastewater. Now, Australian researchers have found a way to purify the waste water and use a simple and scalable electrical process.
The research began with another branch of the project, a team of scientists at the University of Sydney, which is running a pilot plant that is growing microalgae to produce biofuels. Through a process called hydrothermal liquefaction, algae biomass is converted into a high-energy substance similar to crude oil that can be used as a “green” fuel.
The problem is that this process produces a large amount of heavily contaminated wastewater, which contains a lot of carbon, nitrogen and phosphorus. To ensure that the alternative fuel source is as environmentally friendly as possible, researchers began to look for a way to clean up the water. The team used a technique called electrochemical oxidation, in which two electrodes were placed in water, one of which was made from diamond coated with boron. By sending a current, an oxidation reaction is triggered on the surface of the electrode, transforming many contaminants into less harmful products.
“We have adopted an incredibly powerful process that can even eliminate the most persistent non-biodegradable contaminants, such as pharmaceuticals and pesticides, as well as various types of organic compounds that can be found in many industrial wastewaters,” said Julia Ciarini Jungers Soares, lead author of the study. “The process is relatively simple, withno chemicals or harsh operating conditions, and no additional waste.”
The team reported that the electrochemical oxidation process removed up to 99 percent of the carbon from the water and removed 96 percent of the unsightly color. Nitrogen is converted from organic to inorganic forms such as ammonia and nitrates. These are still present in water, but less harmful than other forms of nitrogen. This means that the newly purified water may not meet drinking regulations, but it can still find uses similar to recycled water for watering gardens, cleaning vehicles, agriculture, firefighting and other industrial uses.
The team says the approach is relatively simple and can scale up wastewater from pulp and paper processing, wineries, pharmaceutical production and other industries.
The study was published in the journal Algae Research.