Impacts of microwave pretreatments on the semi-continuous anaerobic digestion of dairy waste activated sludge

Rani, Roopa; Kumar, S. Adish; Kaliappan, S.; Yeom, Ikjun; Banu, J. Rajesh

doi:10.1016/j.wasman.2013.01.016

Cited by 110 publications

(14 citation statements)

References 22 publications

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“…Specifically, a proportional increase in the concentration of soluble sugars, protein and humic acids at 50-160°C (Eskicioglu et al, 2007a;Mehdizadeh et al, 2013). -Higher relative solubilization of proteins compared to carbohydrates (Eskicioglu et al, 2007c;Uma Rani et al, 2013). No degradation of proteins and sugars up to 80°C (8.23 kJ/gTS) (Appels et al, 2013).…”

Section: Process Description and Mode Of Actionmentioning

confidence: 99%

Pre-treatments to enhance the biodegradability of waste activated sludge: Elucidating the rate limiting step

Gonzalez

Hendriks

Lier

et al. 2018

Biotechnology Advances

215

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Pre-treatments for waste activated sludge (WAS) are, in most cases, an attempt to increase the biodegradation and/or improve hydrolysis rate of WAS after anaerobic digestion. This review presents an extensive analysis of WAS pre-treatments effectiveness focusing on increasing the biodegradability. In the first part of the review, WAS is considered as a cluster of organic components: proteins, carbohydrates, humic substances and cells. Based on this breakdown into components, the effect of different pre-treatments on each component (and in combination) is described. Also, possible reasons for the contradictory results frequently found among different studies dealing with the same pre-treatment are included. In the second part, the review describes the effects on volatile solids removal by digestion after pre-treatment and on the dewaterability of the final digestate. The energy balance and potential limiting factors for each pre-treatment are also taken into account. From the published works 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. However, these techniques are very energy intensive and require a large capital outlay, so research on milder pre-treatment techniques is valuable.

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Section: Process Description and Mode Of Actionmentioning

confidence: 99%

Pre-treatments to enhance the biodegradability of waste activated sludge: Elucidating the rate limiting step

Gonzalez

Hendriks

Lier

et al. 2018

Biotechnology Advances

215

View full text Add to dashboard Cite

show abstract

“…The thermal effect is created by the impact of the fluctuating electrical field with bipolar compounds like H 2 O, proteins, fats and other complex molecules. Potency (frequency), dosage, treatment time and dispersion intensity are the major parameters of microwave disintegration that affect the dielectric compounds (Park et al 2010;Uma et al 2013a). The substantial molecular rotary motion of the enduringly and provoked dipoles leads to abrasion that eventually heat the sludge (Dogan and Sanin 2009;Eskicioglu et al 2007;Yu et al 2010).…”

Section: Reaction Mechanism Of Microwave Treatmentmentioning

confidence: 99%

Various Sludge Pretreatments: Their Impact on Biogas Generation

Banu

Kavitha

2017

Waste Biomass Management – A Holistic Approach

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Biogas produced through anaerobic degradation of waste activated sludge (WAS) in wastewater treatment plants has gained much more attention as it is a renewable energy resource. An apparent advantage of anaerobic digestion is the generation of biogas that presents a renewable substitute for utilization of fossil fuels. It was observed that pretreatment has to be done prior to anaerobic degradation (AD) to enhance the biogas generation. This review deals with various pretreatments-chemical, physical, mechanical, combinative, phase-separated pretreatment, their mode of action, advantages and their impact on biogas generation. An extensive review of these pretreatment techniques could plausibly aid in increasing the biogas production and thus rises the sustainable energy generation.

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“…The recovery rate, concentrate grade and separation efficiency are selected as the main indicators to evaluate the separation results (Raj et al 2013;Uan et al 2013;Uma Rani et al 2013). The separation efficiency could be calculated as Eq.…”

Section: Particle Size Distribution Of the Crushing Waste Pcb Slotsmentioning

confidence: 99%

Recovery of valuable metal concentrate from waste printed circuit boards by a physical beneficiation technology

Chen

et al. 2014

Int. J. Environ. Sci. Technol.

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It is greatly significant to separate precious metals from the waste printed circuit boards (PCBs) with appropriate methods for the resource recycling and environment protection. A combined physical beneficiation technology for the recovery of waste PCBs was investigated. Waste PCBs were disassembled into substrates and slots firstly. Waste PCB substrates were crushed to the size below 1 mm by a wet impact crushing approach. The double Rosin-Rammler functions were proposed to describe the particle size distribution characteristic of the substrates. The crushing products of the substrates were separated by a self-designed water-medium tapered column separation bed. The results indicate that the separation efficiency of 93.9 % and metal recovery rate of 93.7 % are obtained with a water discharge of 5.5 m 3 /h, feeding capacity of 250 g/min and inclination angle of 35°. Waste PCB slots were crushed to the size range of 0.5-5 mm by a dry impact crushing approach and separated by an active pulsing air classifier. The separation results show that a separation efficiency of 92.4 % and metal recovery rate of 96.2 % are obtained with the airflow velocity of 2.90 m/s and pulsing frequency of 2.33 Hz. The mismatching components in the metal concentrate are relatively less with suitable operating conditions. Precious metals could be obtained by the further separation and purification of metal concentrates. The technology has great potential to be applied in the field of waste PCB recycling.

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Impacts of microwave pretreatments on the semi-continuous anaerobic digestion of dairy waste activated sludge

Cited by 110 publications

References 22 publications

Pre-treatments to enhance the biodegradability of waste activated sludge: Elucidating the rate limiting step

Pre-treatments to enhance the biodegradability of waste activated sludge: Elucidating the rate limiting step

Various Sludge Pretreatments: Their Impact on Biogas Generation

Recovery of valuable metal concentrate from waste printed circuit boards by a physical beneficiation technology

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