Payload Design for the Lunar Flashlight Mission: Illuminating the Moon's South Pole

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Ozone oxidation of nanofiltration concentrates alleviates membrane fouling in drinking water industry

Nanofiltration is an attractive technology for the production of drinking water from surface water. However, membrane fouling, mainly caused by natural organic matter, increases the costs and limits the water recovery. In this study, it was investigated whether the decomposition of natural organic matter in the concentrate stream by O3, has a positive effect on the membrane flux of four nanofiltration membranes (NF 90, NF 270, Desal 51, NF-PES 10). The results show that O3 oxidation causes a significant alleviation of membrane fouling for every investigated membrane. This is caused by the selective removal of unsaturated bonds and hydrophobic components in the dissolved organic matter, and the decomposition of molecular chains into smaller fragments by O3. However, the chemical oxygen demand could not be reduced by more than 20%. The performance of O3 + H2O2 was only slightly superior to O3 alone, using an identical O3 dose.status: publishe

Kinetic study and scaleup of the oxidation of nanofiltration retentates by ozone

This paper reports on the upscaling of an ozone reactor for the oxidation of natural organic matter. Natural organic matter is responsible for fouling of nanofiltration membranes used for drinking water production. The proposed concept is to feed the retentate stream of a nanofiltration module (400 m^3/h) to an ozone reactor (bubble column) and, subsequently, recycle it to a second nanofiltration module. The ozone oxidation of the retentate stream in the bubble column is analyzed in terms of the two-film theory with mass transfer and chemical reaction. The kinetic regime of the ozonation process, i.e., the chemical reaction rate relative to the mass transfer rate, is determined using data from lab-scale experiments. This information is used for the calculation of the reactor volume and the required ozone dose on an industrial scale. An economic assessment of the integrated nanofiltration – ozone oxidation process is given as well.status: publishe

Kinetic Study and Scaleup of the Oxidation of Nanofiltration Retentates by O₃

This paper reports on the upscaling of an O₃ reactor for the oxidation of natural organic matter. Natural organic matter is responsible for fouling of nanofiltration membranes used for drinking water production. The proposed concept is to feed the retentate stream of a nanofiltration module (400 m³ h^–1) to an O₃ reactor (bubble column) and subsequently recycle it to a second nanofiltration module. The O₃ oxidation of the retentate stream in the bubble column is analyzed in terms of the two-film theory with mass transfer and chemical reaction. The kinetic regime of the ozonation process, i.e., the chemical reaction rate relative to the mass-transfer rate, is determined using data from laboratory-scale experiments. This information is used for the calculation of the reactor volume and the required O₃ dose on an industrial scale. An economic assessment of the integrated nanofiltration–O₃ oxidation process also is given