Carbonaceous DBPs (THMs and HAAs) formation on Cl2 and ClO2 treatment of aqueous soluble fractions of soil-derived natural organic matter

surface water dissolved organic matter feature substantial portion of terrestrial origin and serve as important precursor for toxic disinfection byproduct formation.In the present study, organic matter extracted from the composite...

Removal of Organic Compounds with an Amino Group during the Nanofiltration Process

The research covered the process of nanofiltration of low molecular weight organic compounds in aqueous solution. The article presents the results of experiments on membrane filtration of compounds containing amino groups in the aromatic ring and comparing them with the results for compounds without amino groups. The research was carried out for several commercial polymer membranes: HL, TS40, TS80, DL from various manufacturers. It has been shown that the presence of the amino group and its position in relation to the carboxyl group in the molecule affects the retention in the nanofiltration process. The research also included the oxidation products of selected pharmaceuticals. It has been shown that 4-Amino-3,5-dichlorophenol—a oxidation product of diclofenac and 4-ethylbenzaldehyde—a oxidation product of IBU, show poor separation efficiency on the selected commercial membranes, regardless of the pH value and the presence of natural organic matter (NOM). It has been shown that pre-ozonation of natural river water can improve the retention of pollutants removed.

Combination of Coagulation, Adsorption, and Ultrafiltration Processes for Organic Matter Removal from Peat Water

The high content of natural organic matter (NOM) is one of the challenging characteristics of peat water. It is also highly contaminated and contributes to some water-borne diseases. Before being used for potable purposes, peat water must undergo a series of treatments, particularly for NOM removal. This study investigated the effect of coagulation using aluminum sulfate coagulant and adsorption using powdered activated carbon (PAC) as a pretreatment of ultrafiltration (UF) for removal of NOM from actual peat water. After preparation and characterization of polysulfone (Psf)-based membrane, the system’s performance was evaluated using actual peat water, particularly on NOM removal and the UF performances. The coagulation and adsorption tests were done under variable dosings. Results show that pretreatment through coagulation–adsorption successfully removed most of the NOM. As such, the UF fouling propensity of the pretreated peat water was substantially lowered. The optimum aluminum sulfate dosing of 175 mg/L as the first pretreatment stage removed up to 75–78% NOM. Further treatment using the PAC-based adsorption process further increased 92–96% NOM removals at an optimum PAC dosing of 120 mg/L. The final UF-PSf treatment reached NOM removals of 95% with high filtration fluxes of up to 92.4 L/(m2.h). The combination of three treatment stages showed enhanced UF performance thanks to partial pre-removal of NOM that otherwise might cause severe membrane fouling.

Natural Organic Matter (NOM) Transformations and their Effects on Water Treatment Process: A Contemporary Review

One of the several significant concerns related to water treatment plants is the transformation of natural organic matter (NOM) concerning quality and quantity due to the changing climatic conditions. The NOM consists of heterogeneous functionalized groups. Phenolic and carboxyl groups are the dominant groups that are pH-dependent and show a stronger affinity towards the metals. Properties of natural organic matter and trace elements govern the binding kinetics, influencing cations' binding to functionalized groups at lower pH. The water treatment process mechanisms like adsorption, coagulation, membrane filtration, and ion exchange efficiencies are sturdily influenced by the presence of NOM with cations and by the natural organic matter alone. The complexation among the natural organic matter and coagulants enhances the removal of NOM from the coagulation processes. The current review illustrates detailed interactions between natural organic matter and the potential impacts of cations on NOM in the water and wastewater treatment facilities.

Super-bridging Fibrous Materials for Water Treatment: Impacts on Removal of Plastic Particles, Phosphorus and Natural Organic Matter

To deal with issues of process sustainability, cost, and efficiency, we developed materials reengineered from fibers to serve as super-bridging agents, adsorbents, and ballast media. These sustainable fiber-based materials considerably increased the floc size (~6630 µm) compared to conventional physicochemical treatment using a coagulant and a flocculant (~520 µm). The materials also reduced coagulant usage (up to 40%) and flocculant usage (up to 60%). These materials could be used in synergy with coagulants and flocculants to improve settling in existing water treatment processes and allow facilities to reduce their capital and operating costs as well as their environmental footprint. Moreover, the super-sized flocs produced using fiber-based materials (up to ~13 times larger compared to conventional treatment) enabled easy floc removal by screening, eliminating the need for a settling tank, a large and costly process unit. The materials can be effective solutions at removing classical (e.g., natural organic matter (NOM) and phosphorus) and emerging contaminants (e.g., microplastics and nanoplastics). Due to their large size, Si- and Fe-grafted fiber-based materials can be easily recovered from sludge and reused multiple times.

Influential Mechanism of Natural Organic Matters with Calcium Ion on the Anion Exchange Membrane Fouling Behavior via xDLVO Theory

The fouling mechanism of the anion exchange membrane (AEM) induced by natural organic matter (NOM) in the absence and presence of calcium ions was systematically investigated via the extended Derjaguin–Landau–Verwey–Overbeek (xDLVO) approach. Sodium alginate (SA), humic acid (HA), and bovine serum albumin (BSA) were utilized as model NOM fractions. The results indicated that the presence of calcium ions tremendously aggravated the NOM fouling on the anion exchange membrane because of Ca-NOM complex formation. Furthermore, analysis of the interaction energy between the membrane surface and foulants via xDLVO revealed that short-range acid–base (AB) interaction energy played a significant role in the compositions of interaction energy during the electrodialysis (ED) process. The influence of NOM fractions in the presence of calcium ions on membrane fouling followed the order: SA > BSA > HA. This study demonstrated that the interaction energy was a dominating indicator for evaluating the tendency of anion exchange membranes fouling by natural organic matter.