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One way to cause struvite to precipitate from wastewater is to add other chemicals to the wastewater stream. is chemical conversion causes struvite crystals to form, which can eventually be turned into small pellets with additional processing. Researchers have recently developed ways to use electrochemically precipitation to generate struvite. By applying an electrical current to a phosphorus and nitrogen-containing solution, struvite crystals form on the magnesium electrode – or may even fall to the boom of the container. e sinking crystals can be collected out of the solution. e struvite on the magnesium electrode can also be dried and scraped off for collection. Chemically and electrochemically precipitated struvite can be used as a recycled fertilizer product. Research shows struvite can be an effective alternative to traditional fertilizer phosphorus additions. is creates a circular "nutrient economy" – where the struvite is used as fertilizer, then eaten as food, recovered in wastewater, and then reused. It not only helps the environment by keeping phosphorus and nitrogen out of water bodies and conserves phosphate rock mineral A laboratory-scale, single-cell electrochemical batch reactor used for struvite production. Credit: Laszlo Kekedy-Nagy You might be familiar with the term precipitation. It's what happens when you make rock candy – you dissolve enough sugar into hot water, and larger crystals of sugar form as the water cools. Wastewater treatment plants work to purify water so that it can be reused. ey fall under strict standards from the Environmental Protection Agency. Struvite can precipitate from wastewater in similar ways to rock candy formation. Scientists have found it is possible to pull struvite from wastewater, which can be done on a large scale. Researchers have developed new technologies to precipitate struvite at strategic locations in wastewater treatment plants. ey've also found ways to precipitate struvite from other liquid waste streams, including municipal landfills and animal and industrial wastewaters. ese processes remove excess phosphorus and nitrogen and make them available for reuse. (Left) Pelletized, chemically precipitated struvite by Ostara Nutrient Recovery Technologies Inc. Recovering struvite from wastewater can benefit the environment. (Right) Powdered, electrochemically precipitated struvite created in the laboratory from synthetic wastewater. Credit: Niyi Omidire How is struvite recovered from wastewater? resources. In addition, it may be possible to use struvite that is made regionally, reducing the transportation costs and greenhouse gas emissions from transportation. 45 farm406

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