Comprehensive Analysis of Foulants in an Ultrafiltration Membrane Used for the Treatment of Bleach Plant Effluent in a Sulfite Pulp Mill

Abstract

Fouling is a major obstacle in the introduction of membrane processes in new applications in the pulping industry. Due to the complex nature of the feed solutions, complementary analysis methods are usually needed to identify the substances involved. Four different methods were used for the comprehensive analysis of a membrane removed from an ultrafiltration plant treating alkaline bleach plant effluent in a sulfite pulp mill to identify the substances causing fouling. Magnesium was detected both on the membrane surface and in the nonwoven membrane backing and a small amount of polysaccharides was detected after acid hydrolysis of the fouled membrane. This study provides information on foulants, which can be used to improve processing conditions and cleaning protocols and thus the membrane performance in pulp mill separation processes. It also provides an overview of the usefulness of various analytical methods.

Recovery of low molecular weight compounds from alkaline pretreatment liquor via membrane separations

“…58 Silica and polysaccharides have previously been identified as foulants in the ultrafiltration of alkaline pulp from alkaline bleach generated from sulfite pulping. 59 While the permeance of the membrane could be maintained by increasing the transmembrane pressure (constant flux operation), fouling mitigation strategies such as backflushing and chemical cleaning are commonly used to prevent excessive membrane fouling. For example, a 48% increase in the average flux of wastewater from a sulfite pulp process was achieved via backflushing a ceramic membrane for 10 seconds every 120 minutes.…”

Sustainable Alternatives for Tertiary Treatment of Pulp and Paper Wastewater

“…This choice may lead to multiple benefits: (i) improved effluent quality (with reduced environmental impacts) and the possibility of effluent reuse at the factory level, moving towards the "zero-liquid discharge" concept [50]; (ii) reduction of overall freshwater consumption and chemicals usage, with a depletion of greenhouse gases (GHGs) emissions; (iii) better social visibility, with indirect benefits linked to WWTP managing company reputation. However, the negative aspects that may curb this choice are: (i) the huge initial investment cost; (ii) the need for strict cooperation (also at the economic level) between WWTP management company and local industries; (iii) the need for specialized training for WWTP operators to run the ultrafiltration unit, especially to control undesired fouling phenomenon [51].…”

Membrane Operations in the Pulp and Paper Industry for the Recovery of Constituents: A State of the Art Review

“…Further, reported costs for membrane-based processes in the PPI are presented. Applications of MO in wastewater treatment of PPI effluents are beyond the scope of this paper, as this topic is already nicely summarized and discussed in the literature [2,3].…”

“…The advantages of membrane operations (MO), like low energy demand and their selectivity, are well described in the literature [1][2][3][4][5]. The application of MO in the pulp and paper industry (PPI) dates back to the 1970s [4,6,7].…”