Biofouling is detrimental to the hydrodynamic performance of ships. In spite of advances in hull coating technology, a ship must usually undergo underwater hull cleaning to remove biofouling during her in-service time. However, some cleaning practices may also lead to decreased lifetime of the fouling-control coating. Therefore, cleaning forces should be minimized, according to the adhesion str...

A membrane bioreactor (MBR) and an activated sludge process (ASP) were operated side by side to evaluate the change of sludge supernatant characteristics and the evolution of the sludge fouling propensity. The MBR sludge had a higher organic concentration and more biopolymer clusters (BPC) in the supernatant compared with ASP. BPC increased in both concentration and size in the MBR. The results...

A laboratory-scale membrane bioreactor (MBR) and nanofiltration (NF) hybrid system has been built to investigate effects of changes in characteristics of effluent organic matter by the MBR on fouling characteristics of the NF membranes. Large amounts of polysaccharide-like substances with small molecular weight and strong fluorescence intensity at the excitation wavelength of 230nm and the emis...

Membrane fouling precludes the widespread application of membrane filtration system from treating wastewater and drinking water, and occurs even under sub-critical flux operations. Hence the characteristics and behavior of membrane foulants should be thoroughly investigated, so as to find ways to reduce membrane fouling in membrane bioreactors. The purpose of this study is to compare the membra...

Using laboratory assays, we tested whether the secondary metabolites (furanones) on the surface of the red alga Delisea pulchra deter the settlement and growth of a range of ecologically relevant fouling organisms. D. pulchra and 4 other co-occurring seaweeds were almost exclusively fouled by other algae. Consequently, we carried out laboratory assays using propagules from 4 fouling algae (Ulva...

This experimental work investigated the property of membrane fouling for different sludges at high flux 20 L/(m(2)h). The MBR with good aerobic granular sludge performed the longest operation time 61 days, and TMP rose up in a steady overall rate, while only 10, 14 and 19 days for bulking, flocculent and small granular sludge, respectively, which clearly demonstrated the good and complete aerob...

Inorganic micro®ltration membranes with a pore size down to 0.1 mm have been made using laser interference lithography and silicon micro machining technology. The membranes have an extremely small ̄ow resistance due to a thickness smaller than the pore size, a high porosity and a very narrow pore size distribution. They are relatively insensible to fouling, because they have a smooth surface, s...

Nanometer-thin coatings of polyhydroquinone (PHQ), which release and absorb protons upon oxidation and reduction, respectively, were tested for electrochemically induced anti-biofouling activity under the hypothesis that a dynamic pH environment would discourage fouling. Antifouling tests in artificial seawater using the marine, biofilm-forming bacterium Vibrio alginolyticus proved the coatings...

Water purification technologies such as microfiltration/ultrafiltration and reverse osmosis utilize porous membranes to remove suspended particles and solutes. These membranes, however, cause many drawbacks such as a high pumping cost and a need for periodic replacement due to fouling. Here we show an alternative membraneless method for separating suspended particles by exposing the colloidal s...

The technique that employs flash freezing and environmental scanning electron microscopy (ESEM) was utilised for detailed investigation of the fouling materials in a membrane bioreactor (MBR). The method involves the flash freezing of a wet sample in liquid nitrogen for 10s to preserve its structure for direct ESEM observation with a high image resolution. ESEM images show that the sludge cake ...