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Lehigh University logo

Emma Leeds, Rachel Tenney & Yue Wu

Development of Struvite from Wastewater Using Insoluble Magnesium Sources

Department: Environmental Science and Spanish / Chemical Engineering / Civil Engineering and Mathematics
Advisor: Dr. Arthur Kney, Dr. Polly Piergiovanni

Traditional fertilizers currently used on a large scale both are reliant on nonrenewable resources for manufacture and contribute nutrient pollution in waterways because of their fast release of nutrients. Their high water-solubility allows for the runoff of 50% of their nitrogen content into nearby waterways whenever rainfall occurs instead of promoting crop growth. This nutrient pollution contributes to eutrophication, biodiversity loss, climate change, and poor air quality, which in turn affects human health, tourism and recreation, commercial fishing, and the world’s scarce potable water supply. In fact, it is projected that by 2025 two-thirds of the world’s population will live in water-stressed regions, so it is imperative to find ways to keep our water clean. At the same time, by 2050 the global food demand is projected to increase by 60%, so global dependence on fertilizer to optimize crop yield will increase.

This research addresses both global water scarcity and food demand issues by recovering essential nutrients from wastewater to create a sustainable fertilizer. Because municipal wastewater is high in nitrogen and phosphorous, treatment plant effluent contributes to nutrient pollution in waterways. By adding a magnesium source to the wastewater, a magnesium-ammonium-phosphate (MAP) mineral, struvite, precipitates out of the water. Nutrient recovery at a municipal wastewater treatment plant can be more economical and sustainable than eventual pollution mitigation efforts. Previous research has shown that struvite is effective as a slow-release fertilizer, making it a more environmentally-friendly replacement or supplement for traditional fertilizers and compost. The most common magnesium source used to make the struvite is MgCl2, which is a synthetic compound that is highly soluble in water but costly to produce from naturally-occurring sources. This research thus focuses on decreasing the costs associated with struvite production by directly using magnesium sources such as MgCO3 and MgO, which are abundant in nature, with a focus on improving these compounds’ water-solubility as well as improving struvite yield via seeding and ion exchange.

About Emma Leeds:

Emma Leeds is a junior at Lafayette College majoring in Environmental Science and Spanish and is planning on going to graduate school for Environmental Engineering. She is a Clare Boothe Luce Research Scholar who has been working with Professor Arthur Kney on struvite research since Summer 2017 and plans on doing a thesis on the project next year as a senior. In the future, she hopes to combine both her love for languages and Hispanic cultures with her interest in environmental fields, specifically in water treatment and systems. Aside from her research, Emma is also an ECORep, volunteer at the Northampton County Prison, member of the Alpha Gamma Delta sorority, and conducting an Independent Study on the Spanish transition to democracy from the Franco dictatorship.

About Rachel Tenney:
Rachel Tenney is a senior Chemical Engineering major at Lafayette college and is planning to pursue a Ph.D. in Environmental Engineering after graduation. After dabbling in non-Newtonian liquid mixing as a Clare Boothe Luce Research Scholar and in a classical process engineering internship, her research interest in wastewater treatment was sparked by an interdisciplinary Environmental Chemistry course project on global water scarcity. She is dedicated to improving water use as a part of a highly collaborative, multidisciplinary team. In addition to her research, Rachel is involved with LGBT+ advocacy on campus, professional engineering societies including AICHE and SWE, and (grudgingly) Dance Company. She loves her family, friends, animals of all kinds, and Birkenstocks.

About Yue Wu:
Yue Wu is a sophomore at Lafayette College majoring in Civil & Environmental Engineering and Mathematics. She has a special interest in the chemistry and mathematics involved in environmental sciences. She is an EXCEL Research Scholar and has been working in Professor Kney’s lab since fall 2016. She is passionate about doing research and looks forward to continuing research in graduate school to do more for the environment.