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Design and preliminary implementation of onsite electrochemical wastewater treatment and recycling toilets for the developing world

Cid, Clément A. and Qu, Yan and Hoffmann, Michael R. (2018) Design and preliminary implementation of onsite electrochemical wastewater treatment and recycling toilets for the developing world. Environmental Science: Water Research & Technology, 4 (10). pp. 1439-1450. ISSN 2053-1400.

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Self-contained toilet wastewater treatment system prototypes based on electrochemical oxidation of feces and urine using bi-layered semiconductor anodes ([Bi_2O_3]_z[TiO_2]_(1 z)/Ir_xTa_yO_2/Ti) have been designed, constructed, and implemented in regions where access to proper and sufficient sanitation is limited. Prototypes were designed to fit in shipping containers in order to provide toilets and onsite wastewater treatment with clean water recycling. Units were designed to handle the waste of 25 users per day (or 130 L of toilet wastewater). The first prototype was tested on the Caltech campus (Pasadena, California) followed by improved second-generation prototypes that were subsequently installed in India (Ahmedabad, Gujarat and Kottayam, Kerala) and China (Yixing, Jiangsu) for open use in various public settings. The various prototypes were able to provide for the disinfection of pathogens (<10 MPN Total coliforms and <1 MPN Fecal coliform indicator organisms per 100 mL), reduction of chemical oxygen demand (<100 mg O_2 L^(-1)), ammonia (< 10 mg N L^(-1)), and color at an average energy consumption of less than 180 Wh per user per day. The treated wastewater was recycled for use as toilet flushing water.

Item Type:Article
Related URLs:
URLURL TypeDescription Information
Cid, Clément A.0000-0002-7293-035X
Hoffmann, Michael R.0000-0001-6495-1946
Additional Information:© 2018 Royal Society of Chemistry. The article was received on 04 Apr 2018, accepted on 27 Jul 2018 and first published on 07 Aug 2018. This article is part of the themed collection: Sanitation. The authors acknowledge Mr. Garvit Singh (Indian Institute of Technology, Ahmedabad, Gujarat), Mr. Arun Babu, and Mr. Shalu Achu (Mahatma Gandhi University, Kottayam, Kerala) for their help with the technical analyses in the respective field testing sites, as well as Ms. Heather Crammer (California Institute of Technology, Pasadena, California) for her help with the bacterial analyses and Mr. Asghar Aryanfar for the CAD rendering reproduced Figure S2 and Figure S4. This research was supported by the Bill and Melinda Gates Foundation under RTTC Grants OPP 1069500 and OPP 1111246. There are no conflicts of interest to declare.
Funding AgencyGrant Number
Bill and Melinda Gates FoundationOPP 1069500
Bill and Melinda Gates FoundationOPP 1111246
Subject Keywords:onsite sanitation; electrochemical wastewater treatment; chlorine disinfection
Issue or Number:10
Record Number:CaltechAUTHORS:20180807-103034501
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:88620
Deposited By: Tony Diaz
Deposited On:07 Aug 2018 17:43
Last Modified:03 Mar 2020 13:01

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