The efficiency in water treatment by granulated complexes formed from the clay bentonite with (i) micelles of the cations of octadecyltrimethyl-ammonium (ODTMA) or (ii) liposomes of didodecyldimethyl-ammonium (DDAB) was investigated. The bentonite–ODTMA complexes were synthesized in three variations: I. mass ratio of 68/32, which resulted in an excess of positive charge of half of the clay cation exchange capacity and is denoted “ordinary”; II. complexes having higher loads of ODTMA, denoted “enriched”; and III. “neutral”. These variations were designed to optimize the efficiency and reduce the costs of water treatment. “Ordinary” and “neutral” complexes of DDAB were also synthesized. The “ordinary” complex of ODTMA was shown to be efficient in the removal of anionic/hydrophobic molecules and bacteria. The “enriched” complexes were more active in removal of bacteria from water by filtration due to the higher release of free ODTMA cations, which causes biostatic/biocidal effects. The corresponding “ordinary” and “neutral” complexes of ODTMA and DDAB yielded the same efficiency in removal from water of the neutral and hydrophobic herbicides, S-metolachlor (i) and alachlor (ii), respectively. Model calculations, which considered sorption/desorption and convection yielded simulations and predictions of filtration results of the herbicides. The neutral complexes are advantageous since their production saves about 1/3 of the amount of ODTMA or DDAB, which constitutes the expensive component in the respective composite.

Granulated micelle–clay complexes including the organic cation octadecyltrimethylammonium (ODTMA) were shown to be efficient in removal of total bacteria count (TBC) from water. Microwave (MW) heating of granules to restore bacterial removal was investigated. Drying of granules by MW required 20-fold less energy than by conventional heating. When water content of granules approached 10%, or less, their heating period by MW had to be below 1 min, e.g., 30 s, and less, in order to avoid ignition and irreversible structural changes. Structural and thermal properties of MW heated samples were studied by FT-IR spectra and thermo gravimetric analyses (TGA). Inactivation of bacteria in water was more efficient by MW than by conventional oven, or by electric plate. For elimination of bacteria from water, MW heating was at least five-fold more efficient than by conventional heating. The results have established an adequate regeneration procedure by MW heating at durations depending on the remaining percentage of water associated with the granules. Tests of first and second regenerations by MW heating, and HCl washing of columns, were carried out. It was concluded that MW treatment may be chosen for optimal regeneration of the granulated micelle–clay complex as an efficient and low-cost procedure.

Granulated micelle-clay composites (0.3 to 2mm) formed from Na-bentonite and the organic cations Octadecyltrimethylammonium (ODTMA), or Benzyldimethylhexadecylammonium (BDMHDA) were employed to remove from water by filtration (a) Escherichia coli S-17 and (b) total bacteria count (TBC). In (a) filters included 4g to 27g of complex mixed with sand, and bacteria numbers were 6.4·105 to 5·106/mL. A model which considered convection, adsorption, and desorption simulated the filtration results and yielded predictions. Bacteria capture by filtration was independent of the complex used, but BDMHDA complexes were superior in reducing numbers of emerging bacteria, due to a larger biocidal, or biostatic effect of released cations. Placing a layer of activated carbon after the micelle-clay filter reduced the released cations to 1μg/L. Regeneration was by: (i) passing a solution of 0.1% NaOCl, or 0.01M of HCl, or (ii) heating in a furnace at 105°C for 2.5h. Capacities for removal of bacteria after first and second regenerations by (i) were 86% and 57% of those with fresh granules, respectively. It is suggested that the technology can provide a safe and economical treatment for drinking water contaminated by pathogenic bacteria. In (b) the capacity of filters was smaller than in (a), but the technology enables to avoid using UV lamps in domestic filters.

Reuse of grey water (GW) enables to reduce fresh water consumption, but a treatment is required to prevent potential transmission and propagation of pathogenic organisms. This study presents results on the removal of pathogenic bacteria from GW as well as reduction of turbidity, TSS COD, and BOD by a novel treatment system. Compared to previous studied methods, three new elements are presented in the current treatment of GW: (1) A granulated complex of micelles of the organic cation octadecyltrimethylammonium (ODTMA) with montmorillonite was employed in filtration of GW. This complex was efficient in purifying GW due to its large surface area, positive charge and existence of hydrophobic domains. The granulated complex enabled flow when present exclusively in the filter; (2). A moving bed reactor for decomposition of part of the organic matter in the GW. This pretreatment stage, prior to the micelle-clay filter, was also efficient in removing pathogenic bacteria; (3) A regeneration stage of the micelle-clay filter conducted by passing either dilute solutions of Na-hypochlorite or HCl through the micelle-clay complex, or by heating the complex. Incubation of GW for either two weeks or one day in the pretreatment stage yielded a 10- and 7-fold enhancement in the volume filtered, which did not contain fecal coliforms, i.e., 300 and 210L for 40g of complex, respectively. The capacity of purified volume per gram of the complex increased further several-fold (>23L/g) for filters filled exclusively with granules. Regeneration of the complex in the filter further enhanced the capacity.

A technology for purification of water from perchlorate by filters including a complex between micelles of octadecyltrimethylammonium (ODTMA) and a clay-mineral, montmorillonite (Mt), or bentonite is presented. Laboratory filters of lengths of 20 and 40cm were filled with a powdered micelle (ODTMA)–Mt complex mixed with excess sand at ratios of 1:100 to 1:15 w/w. A pilot filter (60cm diameter∙110cm length) was filled with a 1:19 mixture. The complex exhibited a relatively large affinity to adsorb perchlorate; the presence of other anions, such as chloride, nitrate and sulfate at concentrations exceeding 1000-fold those of perchlorate had little effect on its removal from water by filtration. This high affinity was explained by the fact that the positively charged complex has abundance of hydrophobic regions, whereas perchlorate, is characterized by a large bare anionic radius, i.e., a loose hydration shell. A model which accounts for convection, adsorption and desorption was adequate in simulating and predicting the kinetics of filtration for two orders of magnitude variation in concentrations of perchlorate and one order of magnitude variations in concentrations of adsorbing sites, filter length, and flow velocities. Production of a granulated complex enabled to fill the filters exclusively with the complex and make the technology suitable for upscale. Based on the results of pilot experiments and model calculations, it is suggested that in comparison with other technologies, the micelle–clay filter has a relatively large capacity to remove perchlorate in the range of hundreds to thousands μg/l.