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Conclusions and outlook
Published in Nirajan Dhakal, Controlling Biofouling in Seawater Reverse Osmosis Membrane Systems, 2017
On the other hand, the MFS operated with permeate of tight UF alone showed an increase in pressure drop of approximately 500 mbar after 17 days of operation. The increase in pressure drop in MFS cells fed with the permeate of tight UF could possibly be due to the passage of low molecular weight (LMW) organics (used to grow algae) as well as dissolved phosphate. A preliminary investigation performed with a range of EDTA concentrations (origin of LMW) showed a moderate linear correlation (R2 = 0.65) with the measured net bacterial regrowth potential. This suggests that the application of PRT™ downstream of tight UF could be a good option to delay the onset of biofouling in SWRO systems. Moreover, long-term experiments are required to verify these preliminary findings.
Ion-Exchange Methods for Ultra Purification of Inorganic, Organic and Biological Substances
Published in Dmitri Muraviev, Vladimir Gorshkov, Abraham Warshawsky, Ion Exchange, 1999
Dmitri Muraviev, Vladimir Gorshkov, Abraham Warshawsky
The analysis of the literature shows that the unified sorbents combining all the above requirements are practically not available [1-4]. The choice of the optimum sorbent is also complicated by the high variety of sorbents of different types and by the absence of the uniform criteria for their comparison, which could help to evaluate the effectiveness of their use under given conditions. The parameters, which are usually applied for this purpose involve the permitted concentration of the contaminants in the treated solution and/or the desired purification level, the full and equilibrium ion-exchange capacities towards given ionic species and some others. Accumulation of the desired data requires long term experiments usually under dynamic conditions. In certain cases a correct comparison of different sorbents can not be done because the determined values depend on a number of system variables, which can be estimated quantitatively with difficulty.
Forward osmosis performance in extracting water from produced water
Published in Journal of Applied Water Engineering and Research, 2022
Razieh Ahmadizadeh, Soheila Shokrollahzadeh, Seyed Mahdi Latifi
It is obvious that the presence of oil in the feed solution can enhance the membrane fouling during a long-term experiment, and to investigate this phenomenon, the membrane fouling within a long-term experiment of the FO process was studied. Figure 4 shows the water flux profile during about 5000 min (14 runs, each one about 6 h). After each run, both the feed and draw solutions were replaced with fresh ones; therefore, the effects of concentration changes on the FO performance can be ignored. The obtained flux at the beginning of the experiment was 8.48 L/(m2h) but after 9 and 14 runs it reduced by 24.5 and 37%, respectively (Figure 4). Further decline of the flux observed after 9 runs can be attributed to foulant – foulant interactions near the surface of the cake layer.
Can a humanoid robot continue to draw attention in an office environment?
Published in Advanced Robotics, 2020
Yuki Okafuji, Jun Baba, Junya Nakanishi, Itaru Kuramoto, Kohei Ogawa, Yuichiro Yoshikawa, Hiroshi Ishiguro
Gockley et al. conducted a long-term experiment at a university using a reception robot with a graphic face on display [16]. The robot exhibited character and personality, and read stories that were changed every week to maintain novelty. Throughout this nine-month experiment, a certain number of visitors continued to interact with the robot. Koay et al. investigated how habituation effects changed user preferences regarding a robot [17]. Four types of robots were placed in an office for five weeks, at high/low heights and with/without faces. The results showed that humans preferred human-like robots during the habituation process. Penders et al. also used multiple robots to evaluate the habituation effects in long-term interactions [18]. Graaf et al. placed a rabbit-type robot in a home for six months, and investigated how long the users continued to use it [19,20]. The robot had dialog functions such as reciting news and weather. These studies show that most people do not continue to use the robots. Through experiments, acceptance variables such as utilitarian attitudes, hedonic attitudes, and social norms were evaluated to analyze how people feel when using robots. Other studies have investigated the sociological perspectives associated with Roomba (developed by iRobot Corporation) [21,22], and differences in acceptance depending on the culture [23].
Use of sponge iron dosing in baffled subsurface-flow constructed wetlands for treatment of wastewater treatment plant effluents during autumn and winter
Published in International Journal of Phytoremediation, 2022
Muyu Feng, Jinming Liang, Peng Wang, Ya’e Wang, Jie Li
Yang et al. (2021) added some NaNO3 to the anaerobic serum bottle containing anaerobic iron sludge. After eighteen days, the microbiological analysis showed that no known NAFO bacteria were found at the genus level, and there was no NO3−-N reduction. The reason is chemical denitrification. During a long-term experiment using a ZVI-based ICAD device, Liu et al. (2020) found that hydrogenophaga bacteria dominated hydrogen autotrophic denitrification bacteria, which may be a degradative species of NO3−-N. These reactions also illustrate that with no NAFO sludge added, the possibility of NAFO reactions occurring in reactors dosed with iron is low.