Insight into the effect of organic and inorganic draw solutes on the flux stability and sludge characteristics in the osmotic membrane bioreactor

Muhammad Saboor Siddique; Sher Jamal Khan; Muhammad Aamir Shahzad; Muhammad Saqib Nawaz; Nicholas P Hankins

doi:10.1016/j.biortech.2017.10.064

Insight into the effect of organic and inorganic draw solutes on the flux stability and sludge characteristics in the osmotic membrane bioreactor

Bioresour Technol. 2018 Feb:249:758-766. doi: 10.1016/j.biortech.2017.10.064. Epub 2017 Oct 19.

Authors

Muhammad Saboor Siddique¹, Sher Jamal Khan², Muhammad Aamir Shahzad¹, Muhammad Saqib Nawaz³, Nicholas P Hankins⁴

Affiliations

¹ Institute of Environmental Sciences and Engineering (IESE), School of Civil and Environmental Engineering (SCEE), National University of Sciences and Technology (NUST), Sector H-12, Islamabad, Pakistan.
² Institute of Environmental Sciences and Engineering (IESE), School of Civil and Environmental Engineering (SCEE), National University of Sciences and Technology (NUST), Sector H-12, Islamabad, Pakistan. Electronic address: s.jamal@iese.nust.edu.pk.
³ 3W Systems (Private) Limited, Near Johar Town, Lahore, Pakistan.
⁴ Department of Engineering Science, The University of Oxford, Parks Road, Oxford OX1 3PJ, UK.

PMID: 29136930
DOI: 10.1016/j.biortech.2017.10.064

Abstract

In this study, chloride based (CaCl₂ and MgCl₂) and acetate based (NaOAc and MgOAc) salts in comparison with NaCl were investigated as draw solutions (DS) to evaluate their viability in the osmotic membrane bioreactor (OMBR). Membrane distillation was coupled with an OMBR setup to develop a hybrid OMBR-MD system, for the production of clean water and DS recovery. Results demonstrate that organic DS were able to mitigate the salinity buildup in the bioreactor as compared to inorganic salts. Prolonged filtration runs were observed with MgCl₂ and MgOAc in contrast with other draw solutes at the same molar concentration. Significant membrane fouling was observed with NaOAc while rapid flux decline due to increased salinity build-up was witnessed with NaCl and CaCl₂. Improved characteristics of mixed liquor in terms of sludge filterability, particle size, and biomass growth along with the degradation of soluble microbial products (SMP) were found with organic DS.

Keywords: Draw solutes; Membrane distillation; Osmotic membrane bioreactor; Reverse solute transport; Salinity buildup.

MeSH terms

Bioreactors
Membranes, Artificial
Osmosis
Sewage*
Water Purification*

Substances

Membranes, Artificial
Sewage