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The effects of temperature, storage time and water pH on the coagulation performance of okra seed protein in water treatment were assessed. In a jar test experiment, okra salt extract achieved a notable improvement in treatment efficiency with storage time and showed good performance in quality after thermal treatment at 60, 97 and 140 °C temperatures for 6, 4 and 2 hours, respectively. The performance improvement of more than 8% is considered to be due to the denaturation and subsequent removal of coagulation-hindering proteins in okra seed. Furthermore, the results of a sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis show two distinctive bands of protein responsible for the coagulation process after denaturation. It was further shown that at optimal coagulant dose, the pH of the treated water remained unaffected as a result of the protein's buffering capability during coagulation. Therefore, denatured okra seed exhibited improved performance compared to the native crude extract and offers clear benefits as a water treatment coagulant. [ABSTRACT FROM AUTHOR]

Optimization of organic matter (OM) removal is of key importance for effective water treatment, as its presence affects treatment processes. In particular, OM increases the operational cost of treatment caused by increased coagulant and disinfectant demands. In the work reported here, fluorescence spectroscopy is used to assess the effect of changing coagulation pH on OM removal, character, and composition. The results of a 3-month trial of low pH coagulation operation at a major surface water treatment works in the Midlands region of the UK are discussed, together with the effect upon total organic carbon (TOC) removal. OM removal was assessed on the basis of both measured removal and fluorescence-inferred removal (through intensity-reduction measurements). Fluorescence spectroscopy demonstrated that optimized coagulation affects the quantitative and qualitative OM properties. Fluorescence analyses were shown to complement other OM measurements, with reductions of peak intensities correlating well with removal of TOC in a range of different treatment conditions. [ABSTRACT FROM AUTHOR]

Floc characteristics play a major role in the removal of contaminants from water in physicochemical treatment processes. The efficiency of the main removal processes is a function of floc size, strength and density. Changes in these parameters affect floc removal and hence the removal of adsorbed organic matter. Coagulation and flocculation efficiency and floc strength are often assessed using a jar tester. Here, CFD was used to model the flow field within a standard jar test apparatus and, using a Lagrangian particle trajectory model, to study the effects of turbulence on individual flocs. Combining numerical and experimental data, velocity gradient values at which floc breakage occurs are postulated for three different floc suspensions. Although the threshold values are determined using jar test and CFD data in combination, they are based on the flocs' resistance to induced velocity gradients. This is a significant result, as previous breakage thresholds have been expressed in terms of mixing speed and cannot be applied at full scale. The results shown here can be adopted for use in other situations and can be used to assess the performance of existing flocculators or to design new installations. [ABSTRACT FROM AUTHOR]

NOM deteriorates water quality by forming taste, clarification, colour, and odour problems. It also increases coagulant and chlorine consumption which can initiate disinfection by-products harmful to human health. The coagulation-flocculation (CF) technique is an established method commonly employed to remove NOM in water treatment. Plant-based coagulant products (PCPs) derived from plants like the Moringa oleifera (MO) Strychnos potatorum Linn and Opuntia ficus indica, have been studied and proposed as sustainable alternatives to chemical coagulant, like, aluminium sulphate due to their abundant availability, low cost, low sludge volume and disposal cost, and biodegradability. This review paper provides an overview of the most widely studied plant-based coagulants and discusses their NOM and turbidity removal. It investigates recent analytical tools applied in their characterisation and floc morphological studies. The paper also investigates the effects of operating parameters such as coagulant dose, temperature, and pH, on NOM and turbidity removal. It also reviews up-to-date PCPs biophysical properties and CF mechanism and examines the efficiency of their extraction methods in reducing NOM. Finally, it discusses and suggests ways to overcome commercialisation draw-back caused by nutrient addition. [Display omitted] • Natural organic matter (NOM) removal by plant-based coagulation products (PCPs). • Critical appraisal of PCP's biophysical properties and factors affecting their turbidity and NOM removal. • Floc characterization and nutrients contribution by the PCPs. • Detailed overview of the coagulant's preparation and purification process. • Problem associated with PCP use. [ABSTRACT FROM AUTHOR]

This study evaluates the coagulation performance of kenaf protein fractions (KPFs) comprising of albumin (AlbKP), globulin (GloKP), prolamin (ProKP), and glutenin (GluKP), in the treatment of high (500 NTU), medium (150 NTU), and low (30 NTU) turbidity water. Based on preliminary experimental results, the study focused on GloKP due to it outperforming the other kenaf coagulation products (KCPs) in all water types tested. The influence of GloKP, both as a primary coagulant and coagulant aid to aluminum sulfate (AS) on organic matter removal, was examined. Parametric analysis on turbidity, TSS, pH, dosages, retention time, and KPFs storage time was completed. Results indicated that GloKP could be used both as a primary coagulant and coagulant aid. GloKP had a higher turbidity and solids removal than the AlbKP and other KPFs (ProKP and GluKP). Solution pH greatly influenced the performance of the GloKP, and optimum dosage at pH 2 resulted in the highest organic matter removal. High dosages also resulted in negative mobility of particles and a more stable suspension. When used as a coagulant aid to AS, GloKP was more effective in removing dissolved organic carbon (DOC). Scanning electron microscopy elemental analysis (SEM‐EDAX) and Fourier transform infrared (FT‐IR) spectra showed the structure of the KPFs. SEM‐EDAX indicated the presence of metal cations capable of forming complexes essential for flocs formation. The enhanced floc formation, detailed in this paper, is ascribed to the collective effect of charge neutralization of the AS species and the adsorption and bridging effect of the GloKP, which improves the bonds formed between flocs. The coagulation–flocculation process can be significantly improved using dual coagulants. GloKP was also an excellent alternative to its crude (CrKP) and solvent extract (HxKP) form for removing suspended and dissolved particles from all water types. Practitioner Points: Kenaf protein fractionates can destabilize stable particles.The globulin protein fractionate (GloKP) aggregated the most particles and contained least dissolved organic material.GloKP is pH sensitive with pH 2 reported as best working pH.Coagulant dosage and coagulation mechanism were assessed. [ABSTRACT FROM AUTHOR]

Abstract: Organic matter (OM) causes many problems in drinking water treatment. It is difficult to monitor OM concentrations and character during treatment processes due to its complexity. Fluorescence spectroscopy is a promising tool for online monitoring. In this study, a unique dataset of fluorescence excitation emission matrixes (EEMs) (n = 867) was collected from all treatment stages of five drinking water treatment plants (WTPs) situated in diverse locations from subtropical to temperate climate. The WTPs incorporated various water sources, treatment processes and OM removal efficiencies (DOC removal 0%–68%). Despite these differences, four common fluorescence PARAFAC components were identified for characterisation of OM concentration and treatability. Moreover, fluorescence component ratios showed site-specific statistically significant correlations with OM removal, which contrasted with correlations between specific UV absorbance at 254 nm (SUVA) and OM removal that were not statistically significant. This indicates that use of fluorescence spectroscopy may be a more robust alternative for predicting DOC removal than UV spectroscopy. Based on the identified fluorescence components, four optical locations were selected in order to move towards single wavelength online OM monitoring. [Copyright &y& Elsevier]

• Kenafcoagulation products (KCPs) as natural coagulants for NOM removal from water. • Delipidation of Kenaf is crucial during the coagulation-flocculation (C-F) process. • Surface charge of KCPs is negative, and C-F mechanism by adsorption-bridging. • KCPs partially removed the aromatic organic matter from water. • KCPs adds dissolved organic materials to treated water. The Sustainable Development Goal (SDG) 6.1, established by the United Nations General Assembly in 2015, targets universal and equitable access to safe and affordable drinking water for all by 2030. An essential factor in achieving this goal is the harnessing of "green" coagulants – naturally occurring, environmentally friendly materials which are effective coagulants for use in water treatment, with good availability in developing countries, inherent renewable properties and ease of biodegradation. In order to gain from these benefits, it is essential to fully understand how such coagulants may best be utilised, particularly concerning their practical application in developing countries. In this study, three different plant-based coagulation products (PCPs), namely Hexane (HxKP), saline (StKP) and crude (CrKP) extracts of Kenaf plant seed (Hibiscus cannabinus, a species of the Hibiscus plant), were applied to high (HTW), medium (MTW) and low (LTW) turbidity water in order to determine their performance and coagulation ability. The ability of the three Kenaf coagulant products (KCPs) to remove hydrophobic fractions of natural organic matter (NOM) was measured. The impact of KCPs on the treated water organic matter content (a known disinfection by-product (DBP) precursor) was examined using known surrogates of natural organic matter (NOM) i.e. the dissolved organic carbon (DOC), ultraviolet absorbance at 254 (UV 254) and specific ultraviolet absorbance (SUVA 254). Results obtained quantify the implications of using these coagulants during the water disinfection process. A parametric study, measuring the effect of different operating parameters, such as untreated water turbidity, pH, dosages, retention time, and KCP storage time, was completed. Turbidity removal performance for HxKP and StKP was very good with > 90% removal recorded for HTW and MTW, respectively, at pH seven within 2 hours retention time. Images obtained from scanning electron microscopy (SEM) analysis revealed a high likelihood of the coagulation mechanism of KCPs to be adsorption-interparticle bridging brought about by their flake-like structures and surfaces charges. Varying pH had no measurable influence on the coagulation performance of the KCPs. Comparing their efficiency with MoringaOleifera (MO, a previously researched PCP) and alum showed that HxKP had a negligibly different particle removal as MO. StKP turbidity removal performance was below HxKP by 1% for HTW and LTW and 2% for MTW but performed higher than the CrKP by 5% and 7% in HTW and MTW, respectively. The optimum dosage of HxKP and StKP reduced DBP surrogate values, indicating that its precursor is also minimized, although a slight shift from this optimum dosage showed a significant rise in their concentration thus signifying a potential increase in DBPs during disinfection. Image, graphical abstract [ABSTRACT FROM AUTHOR]