Evaluation of Membrane Fouling for In-Line Filtration of Oil Sands Process-Affected Water: The Effects of Pretreatment Conditions

Abstract

Membrane filtration is an effective reclamation option for oil sands process-affected water (OSPW). However, fresh OSPWs contain suspended solids and inorganic constituents in suspended and dissolved forms that can severely foul membranes. Pretreatment of OSPW with coagulation-flocculation (CF) was investigated to determine the effects of different coagulant aids (anionic, cationic, and nonionic polymers) on membrane surface properties and fouling. Our results showed that CF pretreatment effectively enhanced nanofiltration (NF) and reverse osmosis (RO) membrane permeate flux and salt rejection ratio through reducing membrane fouling. It was shown that coagulants and coagulant aids applied to OSPW feedwater can affect membrane physicochemical properties (surface hydrophilicity, zeta potential, and morphology), membrane performance, and the fouling indexes. Membrane rejection of ionic species increased significantly with the inclusion of an anionic coagulant aid and slightly with a cationic coagulant aid. Among three coagulant aids tested, anionic coagulant aids led to the most enhanced membrane performance through increasing membrane surface negativity and decreasing the formation of a fouling layer. Conversely, although cationic coagulant aids were the most effective in reducing OSPW turbidity, the application of cationic coagulant aids promoted the adsorption of foulants on membrane surfaces.

Removal of TiO2 Nanoparticles During Primary Water Treatment: Role of Coagulant Type, Dose, and Nanoparticle Concentration

“…Moreover, an important phenomena involving the effectiveness of metal coagulants is from the pH change caused by hydrolysis of the metal cations (in this case, Al 3 + and Fe 3 + ); the change in pH of the solution governs the metal coagulants' effectiveness during coagulation since metal ion solubility will be affected (Crittenden and Harza, 2005;Gregory, 2005). Others have demonstrated the use of conventional water treatment processes (i.e., coagulation, flocculation, and sedimentation [CFS]) to effectively remove natural organic matter, suspended solids, disinfection byproduct precursors, and other inorganic constituents from water and wastewater (Duan et al, 2002;Domínguez et al, 2005;Beltrán-Heredia et al, 2009;Zhao et al, 2009;Kim et al, 2012). However, even with these studies and many others, the involvement of these removal mechanisms in the destabilization and separation of nanomaterials is yet unknown.…”

Integrated membrane process for wastewater treatment from production of instant tea powders

“…3a, and a steady permeate flux was observed in the first 30 min. The decrease in flux was caused by the settlement of flocs on the membrane surface which formed the cake layer [46]. The combined process using coagulation-flocculation with PAFC and UF showed higher permeate fluxes compared with UF of raw wastewater permeate flux under the same TMP and CFV.…”

Water treatment technologies for the remediation of naphthenic acids in oil sands process-affected water

“…While fouling may, in some cases, be partially reversed through backwashing [94,95] or chemical treatment [94], it requires the additional use of water or some other solvent to redisperse membrane-bound compounds, which then must be stored or treated in some other manner. Therefore, while membrane filtration may aid in accelerating the reclamation process, it would likely require implementation in combination with other techniques, such as coagulation/flocculation [94,97,98].…”

“…Further, coagulation/flocculation processes are often cited as significant producers of sludge [85,88,91], while fouling and poor selectivity are frequent challenges for both membrane filtration and adsorption processes [91,92]. Given the apparent limitations of these individual processes, much of the emerging research in this field is directed toward the treatment of OSPW using a combination of techniques [76,94,97,98,110,113]. In some cases, this has allowed for a much more comprehensive reduction in NA concentration.…”

“…Mehrotra and Banerjee [118] demonstrated the efficacy of using a microfiltration pretreatment unit to reduce membrane fouling in reverse osmosis systems. Kim and coworkers [97,98] proposed the inclusion of coagulation/flocculation prior to nanofiltration and reverse osmosis processes. In both cases, fouling was significantly reduced, allowing for a suitable permeate flux to be maintained for extended periods of time.…”