Treatment of model oily waste water by microfiltration

Zsolt László Kiss,László Talpas,Sándor Beszédes,Zsuzsanna László,Zita Seres,Cecília Hodúr

doi:10.3311/ppch.2166

Zsolt László Kiss, László Talpas + Show 4 more

Open Access

https://doi.org/10.3311/ppch.2166

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Abstract

Microfiltration membranes made from polytetrafluorethylene (PTFE) have been successfully used for the separation of oily waste waters by membrane coalescence, but filtration of the oily waste waters with high emulsifier content have not yet been investigated. Our aim was to examine the effect of emulsifier content on membrane coalescence on this type of membrane, and to investigate the effect of surfactant addition on oil retention and filtration parameters. It was found that the oil content of the emulsion can be separated with MF PTFE membranes. Efficiency of the retention depends on the concentration of emulsion: increasing concentrations resulted in an increased retention. The addition of coagulant also affected filtration parameters: higher coagulant concentrations resulted in a significant increase of the flux, while the retention marginally decreased.

Highlights

Oil in water emulsions of waste waters are produced by industries such as the food industry, and metal-working [1, 2]
Several studies have reported on the use of membrane filtration for the treatment of oil; most studies focused on the use of ultrafiltration (UF) and microfiltration (MF) [7]–[10]
Microfiltration membranes successfully made from polytetrafluorethylene (PTFE) were used for the separation of oily waste waters by membrane coalescence [6]–[13]

Summary

Introduction

Oil in water emulsions of waste waters are produced by industries such as the food industry, and metal-working [1, 2]. They cannot be discharged to the sewer because of a high oil content and high residual organic pollution [3]. Microfiltration membranes successfully made from polytetrafluorethylene (PTFE) were used for the separation of oily waste waters by membrane coalescence [6]–[13]. The addition of surfactants may change the wettability of hydrophobic surfaces, like membranes [15], enhancing the separation efficiency of microfiltration; on the other hand, this may destabilise the oily emulsions, increasing membrane coalescence [16]. The aim of the present work was to investigate the microfil-

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