UGold-Decentralised nutrient recovery from urine with microbial electroconcentration cells

Overview

Nutrient loads on existing treatment plants are on the rise, while regulatory bodies impose ever more stringent discharge limits to safeguard waterways and fisheries. This results in higher costs for plant operators, inevitably leading to larger water bills for users.

To combat ever-increasing loads, the removal and recovery of nutrients at decentralised level has been considered for many years, however none of the proposed solutions so far have reached implementation due to technical or economic hurdles.

In this project, we introduce a novel technology based on bioelectro-concentration of nutrients from source-separated urine. The system captures nitrogen and other nutrients into two product streams:

1. easily-recoverable ammonium bicarbonate salt and
2. a concentrated liquid with approximately 3% nitrogen and 0.5% phosphorus, both of which can find reuse avenues as a fertiliser.

The technology is power and chemical free, thus suitable for decentralised installations at large office and residential buildings, airports, etc.

To date, nitrogen recovery rates of greater than 5.kg-N.m-3.d-1 have been achieved. A pilot plant will be commissioned in early 2017 at the Queensland Urban Utilities Innovation Centre at the Luggage Point wastewater treatment plant.

Collaborators

• Urban Utilities
• ABR Process Development

Project Outcomes

Lab scale proof of concept of a chemical-free system for nutrient recovery from source-separated urine. Key macronutrients contained in human urine can be up-concentrated by a factor of 5 into a liquid concentrate; 30% of recovered nitrogen is in the form of a solid (ammonium bicarbonate).

World first pilot plant for microbial electroconcentration technology has been designed and is currently under construction.

Publications

Journal Publications

1. Monetti, J., Ledezma, P., Virdis, B. and Freguia, S., 2019. Nutrient recovery by bio-electroconcentration is limited by wastewater conductivity. ACS Omega, 4(1), 2152-2159.
2. Jermakka, J., Thompson-Brewster, E., Ledezma, P. and Freguia, S., 2018. Electro-concentration for chemical-free nitrogen capture as solid ammonium bicarbonate. Separation and Purification Technology, 203, 48-55.
3. Ledezma, P., Lu, Y. and Freguia, S., 2018. Electroactive haloalkaliphiles exhibit exceptional tolerance to free ammonia. FEMS Microbiology Letters, 365(2), fnx260.
4. Thompson-Brewster, E., Jermakka, J., Freguia, S. and Batstone, D.J., 2017, Modelling recovery of ammonium from urine by electro-concentration in a 3-chamber cell, Water Research, 124, 210-218.
5. Ledezma, P., Jermakka, J., Keller, J. and Freguia, S., 2017. Recovering Nitrogen as a Solid without Chemical Dosing: Bio-Electroconcentration for Recovery of Nutrients from Urine, Environmental Science and Technology Letters, 4(3), 119-124.
6. Ledezma, P., Kuntke, P., Buisman, C.J.N., Keller J. and Freguia, S., 2015. Source-separated urine opens golden opportunities for microbial electrochemical technologies. Trends in Biotechnology, 33(4), 214-220.

Peer-reviewed Conference Presentations

1. Ledezma, P., Monetti, J., Virdis, B., Keller, J. and Freguia, S. Successful pilot up-scaling, decentralisation and automation of a microbial electrochemical system for nutrient recovery from source-separated urine. 16th IWA Leading Edge Conference on Water and Wastewater Technologies. Edinburgh, United Kingdom, June 2019.
2. Ledezma, P., Monetti, J., Virdis, B., Keller, J. and Freguia, S. First experiences from a decentralised microbial electrochemical pilot for recovery of macro- and micro-nutrients from source-separated urine. IWA Nutrient Removal and Recovery conference. Brisbane, Australia, November 2018.
3. Freguia, S., Pozo, G., Jermakka, J., Vassilev, I., Virdis, B., Ledezma, P. and Keller, J. 2017. Ion exchange membranes turn METs into productive factories. 6th International Conference of the International Society of Microbial Electrochemistry and Technology (ISMET6). Lisbon, Portugal, October 2017.
4. Jermakka, J., Thompson-Brewster, E., Ledezma, P. and Freguia, S. Chemical free nitrogen capture from urine by precipitation as ammonium bicarbonate: overcoming limits of precipitation. 6th International Conference of the International Society of Microbial Electrochemistry and Technology (ISMET6). Lisbon, Portugal.
5. Ledezma, P., Keller, J. and Freguia, S. Decentralised nutrient recovery from human excreta: empowering sanitation coverage by creating value on-site. 14th IWA Leading Edge Technology conference. Florianopolis, Brazil, June 2017.
6. Ledezma, P., Keller, J. and Freguia, S. Decentralised nutrient recovery from urine without added power or chemicals. IWA World Water Congress. Brisbane, Australia, October 2016.
7. Freguia, S., Ledezma, P., Kurlyandchik, I., Lu, Y. (2016). Invited presentation. Alkalophilic community drives high rate electro-concentration of ammonium from urine. 3rd Asia-Pacific meeting of the International Society for Microbial Electrochemistry and Technology (ISMET), Busan (Korea), 30 August – 2 September 2016.
8. Ledezma, P., Keller, J. and Freguia, S. 2016. Microbial Electro-concentration: a flexible technology for self-powered nutrient removal and recovery. 3rd IWA Specialised Conference on Ecotechnologies for Wastewater Treatment (ecoSTP16). Cambridge, United Kingdom, June 2016.
9. Ledezma, P. and Freguia, S. 2016. The golden revolution: bringing microbial electrochemical technologies to market viability. 4th Australian AWA-IWA Young Water Professionals Conference. Sydney, Australia, February 2016.
10. Ledezma, P., Askildsen, M., Keller, J. and Freguia, S. Self-powered nutrient recovery from urine with a microbial fuel cell. 5th International Conference of the International Society of Microbial Electrochemistry and Technology (ISMET5). Arizona, USA, October 2015.
11. Ledezma, P., Askildsen, M., Keller, J. and Freguia, S. Start-up of a microbial fuel cell for nutrient recovery from urine: a proof of concept. IWA Nutrient Removal and Recovery conference. Gdansk, Poland, May 2015.

Posters

• Monetti, J., Ledezma, P., Virdis, B. and Freguia, S. 2018. Recovery of macro- and micro-nutrients from domestic wastewater via bio-electroconcentration. IWA Nutrient Removal and Recovery conference. Brisbane, Australia, November 2018.
• Ledezma, P., Virdis, B., Keller, J. and Freguia, S. 2016. Alternative approaches to bring microbial electrochemical technologies to market: perspectives from down under. The 13th IWA Leading Edge Conference on Water and Wastewater Technologies. Jeréz de la Frontera, Spain, 13-16 June 2016.
• Ledezma, P., Askildsen, M., Keller, J. and Freguia, S. 2015. Microbial electrochemical system for autonomous nutrient recovery from source-separated urine. 12th IWA Leading Edge Conference. Hong Kong SAR, China, 30 May – 3 June 2015.

Thesis

1. Koskue, V. (2017). Master’s thesis. Nitrogen recovery from hydrolysed urine using power-free microbial fuel cell electrodialysis.
2. Plakhotnik, X. (2016). Undergraduate thesis. Bio-electrochemical concentration of nitrogen from wastewater.