Issue 1, 2019

Membrane-separated electrochemical latrine wastewater treatment

Abstract

Electrolysis is demonstrated to be useful for onsite latrine wastewater treatment. Improved wastewater treatment efficiencies are achieved through the use of a combination of cation and anion exchange membranes (CEM/AEM) in electrochemical reactors. Compared to a membrane-free electrolysis cell, the separation of anodic and cathodic chambers using a CEM separator is shown to reduce energy consumption by 51% for COD removal and 87% for NH4+ removal. Furthermore, 51% of the initial [NH4+]0 is recovered via electrodialysis. CEM-separated electrolysis is shown to produce 39% less ClO3 and 92% less chlorinated organic by-products than in a membrane-free reactor. Helminth (Ascaris suum) eggs, which yield parasitic worms, are very resistant to conventional disinfection methods. Membrane-free electrolysis only inactivates 15% of the dosed helminth eggs (100 eggs per mL). In CEM-separated electrolysis, a combination of low pH and in situ chlorine production in the anodic chamber results in 85% inactivation of helminth eggs. In addition, H2, which is produced in the cathodic chamber of the CEM-separated reactor, is directly converted to electricity using a hydrogen–air fuel cell. The hydrogen energy produced during electrolysis is estimated to reduce the overall energy cost of operation by 20%. Recovery of 85% of the initial [PO43−]0 and pH neutralization are achieved by treating the acidic effluent of a CEM-separated electrolysis cell in an AEM-separated electrolysis cell. A one-month continuous operation demonstrates the potential of using both the CEM and AEM during electrolysis to achieve more efficient wastewater treatment while, at the same time, recovering NH4+ and PO43−, for eventual use as agricultural fertilizers.

Graphical abstract: Membrane-separated electrochemical latrine wastewater treatment

Supplementary files

Article information

Article type
Paper
Submitted
07 10月 2018
Accepted
08 11月 2018
First published
20 11月 2018

Environ. Sci.: Water Res. Technol., 2019,5, 51-59

Membrane-separated electrochemical latrine wastewater treatment

Y. Yang, L. Lin, L. K. Tse, H. Dong, S. Yu and M. R. Hoffmann, Environ. Sci.: Water Res. Technol., 2019, 5, 51 DOI: 10.1039/C8EW00698A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements