Characterizing the fluorescent products of waste activated sludge in dissolved organic matter following ultrasound assisted ozone pretreatments
TL;DR: The analysis of the dissolved organic matter by three-dimensional excitation-emission matrix fluorescence spectroscopy showed that the combined pretreatment was superior to the individual ozone and US pretreatments, and also demonstrated the synergetic effect of these two combined Pretreatments.
About: This article is published in Bioresource Technology.The article was published on 2013-03-01. It has received 56 citations till now. The article focuses on the topics: Activated sludge & Ozone.
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TL;DR: This study demonstrates a successful example of waste refinery by converting anaerobic digestion sludge to feasible heavy metal adsorbents to implement the concept of circular economy.
195 citations
TL;DR: This review presents the current and emerging technologies for excess sludge minimization within the process of sewage treatment and guides researchers who are seeking feasible and promising technologies (or processes) to tackle the severe WAS problem.
184 citations
TL;DR: In this paper, a review of the literature on microalgae that were cultivated using captured CO_2, technologies related to the production of bio-fuels from micro-algae and the possible commercialization of micro-algal-based bio-fuel.
Abstract: Fossil fuels, which are recognized as unsustainable sources of energy, are continuously consumed and decreased with increasing fuel demands. Microalgae have great potential as renewable fuel sources because they possess rapid growth rate and the ability to store high-quality lipids and carbohydrates inside their cells for biofuel production. Microalgae can be cultivated on opened or closed systems and require nutrients and CO_2 that may be supplied from wastewater and fossil fuel combustion. In addition, CO_2 capture via photosynthesis to directly fix carbon into microalgae has also attracted the attention of researchers. The conversion of CO_2 into chemical and fuel (energy) products without pollution via this approach is a promising way to not only reduce CO_2 emissions but also generate more economic value. The harvested microalgal biomass can be converted into biofuel products, such as biohydrogen, biodiesel, biomethanol, bioethanol, biobutanol and biohydrocarbons. Thus, microalgal cultivation can contribute to CO_2 fixation and can be a source of biofuels. This article reviews the literature on microalgae that were cultivated using captured CO_2, technologies related to the production of biofuels from microalgae and the possible commercialization of microalgae-based biofuels to demonstrate the potential of microalgae. In this respect, a number of relevant topics are addressed: the nature of microalgae (e.g., species and composition); CO_2 capture via microalgae; the techniques for microalgal cultivation, harvesting and pretreatment; and the techniques for lipid extraction and biofuel production. The strategies for biofuel commercialization are proposed as well.
179 citations
Cites background from "Characterizing the fluorescent prod..."
...Cell rupture by ozonation is due to the oxidative reaction of ozone, which compromises the cell membrane’s ability to regulate the permeability of substances, eventually leading to the outflow of the cytoplasm (Erden et al., 2010; Yang et al., 2013)....
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TL;DR: It is concluded that some pre-treatment techniques, such as thermal hydrolysis, thermal phased anaerobic digestion and low-temperature pre- treatment are effective ways to increase energy production and to improve other sludge properties,such as dewatering.
169 citations
TL;DR: An extensive review about SO 4 -based oxidation applied for sludge disintegration, dewaterability enhancement, metal solubilization, and micropollutant degradation in the sludge is presented in this paper.
149 citations
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TL;DR: The anaerobic digestion of waste activated sludge following ultrasonic pretreatment causing microbial cell lysis was significantly improved and the increase in digestion efficiency was proportional to the degree of sludge disintegration.
776 citations
"Characterizing the fluorescent prod..." refers methods in this paper
...Consequently, US pretreatment is considered to be an effective and promising pretreatment method (Tiehm et al., 2001)....
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TL;DR: Three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy was applied to characterize the extracellular polymeric substances (EPS) extracted from aerobic and anaerobic sludge in wastewater treatment.
627 citations
"Characterizing the fluorescent prod..." refers background in this paper
...Excitation–emission matrix fluorescence spectroscopy can provide fluorescence information about complex organic components by simultaneously changing the excitation and emission wavelengths (Sheng and Yu, 2006)....
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TL;DR: In this article, the effects of ultrasound, sonication and thermal pre-treatment on batch anaerobic sludge biodegradability have been investigated in the same conditions and on the same sludge sample.
Abstract: In order to enhance the efficiency of anaerobic digestion, the effects of ultrasounds, ozonation and thermal pre-treatment have been studied on waste activated sludge. The feature of this study was to carry out the comparison of the three pre-treatments in the same conditions and on the same sludge sample. Each treatment was tested in two conditions close to optimum conditions to maximise batch anaerobic sludge biodegradability. All treatments led to chemical oxygen demand and matter solubilisation and had little influence on mineral matter. In terms of solubilisation thermal pre-treatment was better than sonication or ozonation. But, in terms of batch anaerobic biodegradability, best results were obtained with ultrasounds with an energy of 6250 or 9350 kJ/kg TS and a thermal treatment at 170 or 190 °C. Moreover, treatments had effects on physico-chemical characteristics of sludge samples: apparent viscosity decreased after all treatments but the reduction was more important with thermal treatment. Median diameter of sludge flocs were reduced after sonication, increased after thermal treatment and did not change after ozonation. Finally, capillary suction time (CST) increased after ozonation, increased highly after sonication and was reduced after thermal treatment.
588 citations
"Characterizing the fluorescent prod..." refers background in this paper
...Ozone is a powerful oxidant and disinfectant which is already used in wastewater and waste sludge treatment processes (Bougrier et al., 2006)....
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TL;DR: Results showed that protein was the major substrate for biohydrogen production from sewage sludge and that Eubacterium multiforme and Paenibacillus polymyxa were the dominant bacteria in biohydrogens production from alkaline pretreated sludge at an initial pH of 11.0.
Abstract: Batch tests were carried out to analyze influences of the alkaline pretreatment and initial pH value on biohydrogen production from sewage sludge. Experimental results of the impact of different initial pH on biohydrogen production showed that both the maximal hydrogen yield occurred and that no methane was detected in the tests of at the initial pH of 11.0. The final pH decreased at the initial pH of 7.0−12.5 but increased at the initial pH of 3.0−6.0, probably due to the combination of solubilized protein from sludge and the formation of volatile fatty acids (VFAs) and ammonia during biohydrogen fermentation. The performance of biohydrogen production using the raw sludge and the alkaline pretreated sludge was then compared in batch fermentation tests at the initial pH of 11.0. The hydrogen yield was increased from 9.1 mL of H2/g of dry solids (DS) of the raw sludge to 16.6 mL of H2/g of DS of the alkaline pretreated sludge. No methane and less carbon dioxide (0.8% of control) were present in the biohydr...
405 citations
"Characterizing the fluorescent prod..." refers background in this paper
...Recently, WAS pretreatment methods such as thermal, microwave, alkaline, ultrasonic, and ozone oxidation pretreatments have been used to reduce the amount of WAS, and a range of acceptable results have been reported to date (Cai et al., 2004; Guo et al., 2008; Chu et al., 2009; Xiao and Liu, 2009)....
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TL;DR: The results clearly showed that preconditioning of sludge at high pH levels played a crucial role in enhancing the disintegration efficiency of the subsequent ultrasonic pretreatment, and there exists a certain point where additional energy input is ineffective in achieving further disintegration.
259 citations
"Characterizing the fluorescent prod..." refers background in this paper
...Kim et al. (2010) stated that when the disintegration efficiency of the combined treatment is higher than the sum of the individual disintegration efficiencies, a synergetic effect is present....
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