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Uses of Water and Energy in Food Processing
Published in I. M. Mujtaba, R. Srinivasan, N. O. Elbashir, The Water–Food–Energy Nexus, 2017
Mohammad Shafiur Rahman, Nasser Al-Habsi
Electrolyzed water and ozone are two alternative sanitizing technologies that generate the active oxidizing component on site of food processing and do not use toxic chemical substances. They are safe for handling, distribution, and more environmental friendly as compared to conventional chlorine sanitizers (Deza et al., 2003, 2005; Kim et al., 2003; Yang et al., 2013). Electrochemically activated water is an electrolyzed water sanitizer used for food and food equipment. Electrolysis of dilute sodium chloride solutions generates two distinct fractions, catholyte and anolyte (i.e., sanitizing fraction, which contains different forms of chlorine including hypochlorous acid) (Hricova et al., 2008). The effectiveness of sanitation depends on free available chlorine, oxidation–reduction potential, and pH (Yang et al., 2013). Different types of electrolyzed water are reported to actively kill various foodborne pathogens (Guentzel et al., 2008).
Microbially Inspired Nanostructures for Management of Food-Borne Pathogens
Published in Mahendra Rai, Patrycja Golińska, Microbial Nanotechnology, 2020
Kamel A. Abd-Elsalam, Khamis Youssef, Farah K. Ahmed, Hassan Almoammar
Among the alternative means for water sanitation, electrolyzed water gained particular attention in the food industry as a novel technology for preventing fruit and vegetable contamination in the postharvest environment (Buck et al. 2002). Electrolyzed water is generated by passing a diluted salt solution through an electrolytic cell; when anode and cathode are not separated by a membrane, neutral electrolyzed water containing several active chemical species such as free radicals is produced. The principles of electrolyzed water generation are based on electrolysis of a diluted solution of salts (e.g., NaCl, KCl, MgCl2), which leads to dissociation of salt ions and formation of anions and cations at anode and cathode, negative and positive electrodes, respectively (Al-Haq et al. 2005). The physical properties and chemical composition of electrolyzed water vary with the concentration of salt solution, electrical current, length of electrolysis and water flow rate (Kiura et al. 2002). Most previous studies have assessed the effect of electrolyzing parameters (flow rate, current intensity, and time for electrolysis) on free chlorine, electric conductivity, and pH of the resulting electrolyzed water (Hsu 2003, Abbasi and Lazarovits 2006, Guentzel et al. 2010, Hussien et al. 2017), while very few researchers have studied the effect of electrolyzing parameters on the ability of electrolyzed water to suppress pathogen unit (Fallanaj et al. 2015). Although salt solutions used in electrolysis play a major role in the effectiveness of electrolyzed water, few salts were studied for their effect on electrolyzed water efficiency; among them are sodium chloride (Hsu 2003, Okull and Laborde 2004, Abbasi and Lazarovits 2006, Guentzel et al. 2010, Whangchai et al. 2013, Khayankarn et al. 2014), potassium chloride (Yaseen et al. 2013) and sodium bicarbonate (Fallanaj et al. 2016). Figure 7.1 shows a diagram of the main compartments of electrolysis and the main steps of the electrolyzing process (using the naturally available salts in tap water without additives).
Optimization of a wet scrubber with electrolyzed water spray—Part II: Airborne culturable bacteria removal
Published in Journal of the Air & Waste Management Association, 2019
Zonggang Li, Baoming Li, Weichao Zheng, Jiang Tu, Hongya Zheng, Yang Wang
Electrolyzed water (EW) with wide pH range has been regarded as an alternative sanitizer in recent years, and spraying slightly acidic electrolyzed water (SAEW; pH 5.0–6.5) or neutral electrolyzed water (NEW; 6.5–8.5) has been introduced to lower the microbial concentrations in animal houses, mainly for surface and air disinfection (Zheng et al. 2016c). The cell envelope and dehydrogenase of microbials can be damaged by the main ingredients (HOCl and ClO−) of EW, when the contact between EW droplets and microbials occurs (Nan et al. 2010; Zeng et al. 2010). Unlike other chemical disinfectants, SAEW and NEW caused less corrosion of surfaces and damages to both animal and human health, because no hazardous chemicals were added in their production (Deza, Araujo, and Garrido 2007; Guentzel et al. 2008; Rahman, Ding, and Oh 2010). A wet scrubber with SAEW spray with 70 and 100 mg L−1 available chlorine concentrations (ACCs) significantly and moderately reduced airborne CB emitted from a layer breeding house (P < 0.01) and showed similar removal efficiencies (~40%) (Zheng et al. 2016a). Design optimization of this end-of-pipe system using EW spray is desired to improve airborne CB removal efficiency.
Optimization of a wet scrubber with electrolyzed water spray—Part I: Ammonia removal
Published in Journal of the Air & Waste Management Association, 2019
Zonggang Li, Baoming Li, Weichao Zheng, Jiang Tu, Hongya Zheng, Yang Wang
For mechanically ventilated poultry and livestock houses, air outlets are stationary and agricultural axial fans are in fixed in location. Ammonia emission concentration and emission rate showed opposite variation trends and periodically fluctuated daily and yearly (Lin et al. 2012; Shepherd et al. 2015). The highest ammonia emission rate usually occurred in summer, whereas the ammonia emission concentration was the lowest at that time. With the development of the daily management and manure removal system in livestock and poultry breeding, both ammonia concentration and emission rate in modern AFOs were significantly reduced compared with before (Philippe, Cabaraux, and Nicks 2011). However, further reduction of ammonia emission was necessary to avoid noxious effects on ecosystems. Abatement techniques for ammonia include manure management, diet manipulation, and end-of-pipe treatment (Melse, Oginka, and Rulkens 2009). The end-of-pipe treatment technology was the most efficient way to reduce the contaminants emitted from AFOs, including ammonia. The ammonia removal efficiency could even reach >80% in field experiments (Hadlocon, Manuzon, and Zhao 2014a, 2015; Melse, Ploegaert, and Ogink 2012). Compared with other technologies, including biotrickling filters, water curtains, bioscrubbers, and packed-bed acid wet scrubbers, lower backpressure of spraying wet scrubber, one of the effective end-of-pipe treatment technologies for mechanically ventilated houses, showed the greatest effectiveness in purifying dirty air emitted from AFOs (Hadlocon, Manuzon, and Zhao 2015). Particulate matter, airborne microorganisms, and odorants were also contaminants emitted from the AFOs in addition to ammonia (Fabbri et al. 2007; Gay et al. 2003; Schauberger et al. 2013; Shepherd et al. 2015; Zhao et al. 2016). Higher airborne microorganisms of posttreatment could occur in some end-of-pipe treatment technologies without disinfectant medium (Aarnink et al. 2011; Zhao et al. 2011). Electrolyzed water (EW) was an effective disinfectant, which could be produced by electrolysis of a dilute salt solution. Three types of EW, electrolyzed water (AEW; pH < 2.7), slightly acidic electrolyzed water (SAEW; pH 5.0–6.5), and neutral electrolyzed water (NEW, pH 6.5–8.5), were considered as alternative disinfectants compared with common chemical sanitizer in food and egg industries (Hricova, Stephan, and Zweifel 2008; Huang et al. 2008; Rahman, Khan, and Oh 2016; Zheng et al., 2016b). The combination of antiseptic effect of the disinfectant and washing effect of the scrubber achieved high removal efficiency of microorganisms (Aarnink et al. 2011). Both acidity and disinfection make EW a potential liquid medium for the removal of both ammonia and airborne microbial emitted from AFOs.