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Particles were the most frequent foulants in seawater reverse osmosis (SWRO) desalination. In this study, the fouling characteristic of particles in a large scale SWRO desalination plant from northern China was analyzed systematically by multiple methods. The particle fouling pattern, particle size distribution (PSD), and mineralogical composition were investigated by optical microscopy, scanning electron microscopy with energy dispersive spectrometer, laser diffraction particle size analyzer, X-ray diffraction, and wavelength dispersive X-ray fluorescence spectrometer. Chemical analysis indicated that Na, Mg, Si, and Al were the predominant elements contributing to the fouling particles. The particle deposition had a very broad PSD including ultrafine particles, fine particles, and medium particles due to the failure of the ultrafiltration (UF) system. The mineralogical components were quartz, muscovite, talc, albite, microcline, clinochlore, hematite, and amphibole in descending order. Finally, the long immersing experiment shows that 2.5% hydrofluoric acid processing could eliminate the particles effectively and improve the water flux of the fouled membrane obviously. On the basis of the above results, an in-depth understanding and mitigation of the particles fouling behavior during SWRO desalination would be put forward. [ABSTRACT FROM AUTHOR]

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The cleaning process has a significant environmental impact due to the consumption of resources and chemicals. Laundering procedures were performed in a laboratory washing machine. Orthogonal experiment was carried out to select significant impact factors on washing efficiency and smoothness appearance, and an optimized program was generated according to the experimental results. Compared to the original program, energy consumption of optimized program was reduced by 23%, while the washing efficiency was remained the same. Smoothness appearance of cotton shirt was improved from grade 2.0 to 2.8, which could help to save ironing energy 2.4 kWh and reduce about 2.3 kg CO2-equiv. of the whole lifetime (50 washes). The finding can provide fundamental information to develop a new washing program to achieve good cleaning performance and protect textiles. [ABSTRACT FROM AUTHOR]

[Display omitted] • UF was used to treat micro-polluted water at a mountain village without pretreatment. • The UF process was operated steady without chemical cleaning for almost 2.5 years. • Clean drinking water was obtained and the operation cost was 5.3 cent s·m−3. • The membrane fouling was mainly induced by inorganic-substance-based cake layers. • CaCO 3 was primary in cake layer, whereas Al/Si oxides were only observed on surface. Water treatment technologies that feature a simple operation, affordable cost, and low chemical addition are necessary to achieve the goal of supplying clean water to rural regions. In this study, an automated-control direct ultrafiltration (UF) process without chemical cleaning was operated and investigated using the micro-polluted surface water at a mountain village in China as feed. During the approximately 2.5-year operation, the UF process operated steady without pretreatment and chemical cleaning, and clean drinking water that met the Chinese drinking water standard (GB 5749–2006) was continuously available. Despite occasional shock loading (84.7 NTU), the turbidity (the major contaminant of feed water) was low (0.3 ± 0.1 NTU) in the effluent, and the filtration resistance remained at (14.7 ± 0.7) × 1012 m−1 except for the initial increase. Compared with organic substances, inorganic substances were dominant constituents of cake layer. Alumina or silica particles were easily removed by frequent backwashing and were distributed on the outer surface (newly formed) of cake layer. In contrast, the bulk cake layer was predominantly composed of CaCO 3 scales, indicating its major role in membrane fouling. Regarding organic fouling, low-molecular-weight hydrophilic carbohydrate-like compounds, which were related to bacterial activities, were dominant compositions (91.5%). Proteobacteria made a major contribution to bacterial communities (52.2%). Because of the simple process (almost unattended) and no chemical cleaning, the operation and maintenance cost was only 5.3 cents·m−3 during the entire operation. These findings demonstrate that direct UF without chemical cleaning has significant application potential in rural regions with micro-polluted water. [ABSTRACT FROM AUTHOR]

Abstract: Ultrafiltration of Binxian reservoir (near Harbin in China) water to produce drinking water was investigated in this study. Membrane flux declined with temperature coming down. Using coagulation before UF not only increases the permeate flux, but also retards the permeability decline. In comparison to the normal backwashing in which flow is reversed across the membrane once during each backwash cycle, two consecutive backwashing pulses during each cycle is an optimized operation. A chemical cleaning may be required to restore the initial performance of the membrane when the fouling occurs. As for Binxian reservoir water, 0.1% citric acid is a proper cleaning solution. Membrane filtration offers fewer coagulation agents needed and good quality of produced water. [Copyright &y& Elsevier]