Filtration analysis and fouling mechanisms of PVDF membrane for POME treatment

Mohd Azwan Ahmad,Luqman Chuah Abdullah,Thomas Choong Shean Yaw,Bidattul Syirat Zainal,Nashrah Hani Jamadon

doi:10.2166/wrd.2020.101

Abstract

Abstract Palm oil mill effluent (POME) is a hazardous wastewater which contains high organic constituents and salt concentrations. The ultrafiltration (UF) process is a promising treatment design used for secondary treatment such as POME. However, membrane fouling is the major problem which limits the performance of the UF. This paper describes a detailed investigation of polyvinylidiene fluoride (PVDF) membrane for the treatment of POME. The fouling behavior was analyzed by water flux, fouling mechanism, scanning electron microscopy (SEM), particle size distribution (PSD) and Energy Dispersive X-ray (EDX). It was found that a significant reduction in the permeate flux was caused by the build up of a fouling layer. Study on the fouling mechanism shows that cake filtration dominated the fouling activities on the membrane surface, compared to standard blocking, intermediate blocking, and complete blocking. This result is supported by membrane autopsy through SEM, PSD and EDX.

Highlights

Malaysia is known as one of the largest exporters of palm oil with an average production of crude palm oil of more than 13 million tonnes per year (Subramaniam et al )
The main reason for this phenomenon is because as the feed solution filtered through the UF membranes, the solutes from the feed accumulated on the membrane surface and led to the build up of a gel layer
The aim of this research was originally to study the effect of polyvinylidiene fluoride (PVDF) membrane in the treatment of palm oil mill effluent (POME)

Summary

Introduction

Malaysia is known as one of the largest exporters of palm oil with an average production of crude palm oil of more than 13 million tonnes per year (Subramaniam et al ). The production of wastewater from the palm oil mills, known as palm oil mill effluent (POME), contributes to the highest pollution load that is discharged into rivers all over the country (Taha & Ibrahim ; Ghani et al ). There are three major processes contributing to the production of POME which is hydrocyclone, sterilizer condensate, and oil clarification in a ratio of 1:9:15, respectively (Wu et al ). POME is a thick brownish colloidal with a mixture of oil, suspended solids and water, that is discharged at a temperature of 80–90 C, and considered as a non-toxic wastewater because no chemicals were used during the extraction processes (Alrawi et al ). The properties of POME are 4–5% of total solids, 0.6–0.7% of oil and grease and 95–96% water. It is noted that 85% of the palm oil mill in Malaysia uses a ponding system as a treatment method for POME, but it requires a high retention time and large area of land (Abdurahman & Azhari )

Objectives

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Conclusion