A pilot-scale comparison of mesophilic and thermophilic digestion of source segregated domestic food waste

Banks, C.J.; Chesshire, M.J.; Stringfellow, Anne

doi:10.2166/wst.2008.513

Cited by 83 publications

(38 citation statements)

References 10 publications

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“…In the current study the detrimental effects of ammonia appeared to become evident at around 2500 mg N l -1 (FAN ~1100 mg N l -1 ). This is below the inhibitory TAN concentration observed in mesophilic digesters operating on the same substrate [1], but corresponds to the FAN inhibition threshold found e.g. by Hansen et al [24].…”

Section: Overall Discussionsupporting

confidence: 61%

“…Early digestion trials with this material, however, showed accumulation of volatile fatty acids (VFA) over extended run times in both mesophilic and thermophilic digestion systems [1]. Similar observations were made in a full-scale thermophilic digester treating source segregated restaurant and catering waste [2], and in the UK Government's food waste demonstration AD plant in Ludlow, UK [3]; and have also been demonstrated in laboratoryscale digesters [4,5].…”

Section: Introductionmentioning

confidence: 54%

“…VFA profiles for each digester during the whole experimental run are shown in Earlier studies [1,2] had shown that thermophilic food waste digesters could operate for long periods at even higher VFA concentrations, but may be liable to sudden failure if a change in conditions results in the buffering capacity of the system being exceeded, with a subsequent fall in pH, leading to cessation of methanogenesis and 'souring' of the digester. At day 158 therefore, feeding of all digesters was stopped to see whether they were able to reduce the total VFA concentration and how they would respond to a cessation of loading.…”

Section: Te Supplemented Digestersmentioning

confidence: 99%

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Effect of a Trace Element Addition Strategy on Volatile Fatty Acid Accumulation in Thermophilic Anaerobic Digestion of Food Waste

Yirong

Heaven

Banks

2014

Waste Biomass Valor

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Fax +44 (0)2380 677519 2 AbstractPurpose: A trace element supplementation strategy previously shown to be effective in mesophilic conditions was tested for thermophilic digestion of source segregated domestic food waste.Method: Inoculum from a mesophilic anaerobic digester treating municipal wastewater biosolids was successfully acclimated to thermophilic temperature (55 o C) with food waste as a substrate. Four laboratory-scale digesters were maintained at a loading of 2 g VS l -1 day -1 with one pair receiving trace elements (TE) supplementation. Two more pairs of digesters were incrementally loaded to 3 and 4 g VS l -1 day -1 , respectively, and also received TE.Results: All digesters performed well for the first 3-4 months of operation, but volatile fatty acid (VFA) concentrations in those without TE showed no recovery from an initial small accumulation. On continued operation, VFA concentrations increased in all digesters, especially those at higher loading rates or without TE supplementation, reaching >30 g l -1 .Under these meta-stable conditions, a deliberate disturbance to daily feeding (cessation then resumption) led to acetic acid accumulation, a fall in pH and a sharp increase in the ratio of partial to intermediate alkalinity. Increases in VFA corresponded to an increasing total ammonia nitrogen concentration which appeared to become inhibitory at ~2500 mg N l -1 . It has been shown that in mesophilic conditions accumulation of VFA can be prevented by supplementing with selected trace elements [17][18][19][20]. Mesophilic food waste digesters supplemented with trace elements have been shown to operate with good gas production and low VFA concentrations at ammonia concentrations in excess of 6000 mg l -1 , but with a purely hydrogenotrophic methanogenic population; and a mechanism by which trace element addition can prevent VFA accumulation at high ammonia concentrations has been put forward [18]. Selenium, which is present only in low concentrations in food waste, has been shown to be essential in preventing propionic acid accumulation by providing the co-enzymes 4 necessary for the reduction of formate, one of the metabolic products of propionate degradation. At higher organic loading rates (OLR) additional cobalt is also required. This is thought to be necessary as in these high ammonia conditions all of the organic carbon is converted to carbon dioxide through syntrophic acetate oxidation by the reverse WoodsLjungdahl pathway; in conjunction with the reduction of carbon dioxide to methane by the hydrogenotrophic route, this leads to an increase in co-enzyme demand. Where formate oxidation does not occur there is an accumulation of propionic acid and other longer-chain VFAs, leading eventually to a fall in pH and cessation of methanogenesis [18]. ConclusionsThe current study investigated the extent to which a trace element addition strategy successfully applied in mesophilic conditions could prevent VFA accumulation in thermophilic digesters operating on source segregated food waste, in conditions...

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Section: Overall Discussionsupporting

confidence: 61%

Section: Introductionmentioning

confidence: 54%

Section: Te Supplemented Digestersmentioning

confidence: 99%

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Effect of a Trace Element Addition Strategy on Volatile Fatty Acid Accumulation in Thermophilic Anaerobic Digestion of Food Waste

Yirong

Heaven

Banks

2014

Waste Biomass Valor

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“…This is comparable to the 92% of volatile matter content obtained from the kitchen waste from Burford, Shropshire [11]. Wastes with high volatile matter content produce more biogas if digested properly, as it is the organic matter that produces biogas.…”

Section: B Ash Contentsupporting

confidence: 60%

Potential of Using Kitchen Waste in a Biogas Plant

Apte¹,

Cheernam²,

Kamat³

et al. 2013

IJESD

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Abstract-India's economic growth is contributing to a massive increase in the generation of solid waste. Approximately 55 million tones of Municipal Solid Waste is generated annually by urban areas in India. Over 59% of homes in urban India use Liquified Petroleum Gas (LPG) supplied in portable cylinders for their cooking needs. However, due to our country's dwindling petroleum reserves and increased costly imports of petroleum, non conventional energy resources are slowly gaining importance. The use of biogas using kitchen waste as feedstock can help solve the problem of energy deficit and at the same time, allow the safe disposal of kitchen waste which is often unscientifically dumped or discarded. Our institute campus (Bhavans' campus) has a number of campus kitchens that utilize several LPG cylinders and also generate large amounts of kitchen waste. The kitchen waste generated has high calorific value and moisture content; hence it can be anaerobically digested. The biogas produced can be used to supplement the fuel requirements of the campus kitchens that generate the kitchen waste. This study consists of carrying out survey, characterization of kitchen waste from several kitchens and exploring it's potential to be used for biogas production.Index Terms-Biogas, municipal solid waste, kitchen waste, calorific value.

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“…It has been reported on a number of occasions that digestion at high ammonia concentrations can give stable biogas production at alkaline pH over extended periods of time under continuous loading conditions. In digesters treating food waste these conditions can also lead to operation at elevated levels of volatile fatty acids in the digestate (Banks et al, 2008, Neiva Correia et al, 2008. Similar conditions have been reported in thermophilic cattle slurry digesters (Neilsen and Angelidaki, 2008), and in other nitrogen rich substrates such as slaughterhouse waste Wang, 1999, Wang andBanks 2003).…”

Section: Introductionmentioning

confidence: 99%

Anaerobic digestion of source-segregated domestic food waste: Performance assessment by mass and energy balance

Banks

Chesshire

Heaven

et al. 2011

Bioresource Technology

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321

116

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An anaerobic digester receiving food waste collected mainly from domestic kitchens was monitored over a period of 426 days. During this time information was gathered on the waste input material, the biogas production, and the digestate characteristics. A mass balance accounted for over 90% of the material entering the plant leaving as gaseous or digestate products. A comprehensive energy balance for the same period showed that for each tonne of input material the potential recoverable energy was 405 kWh. Biogas production in the digester was stable at 642 m 3 tonne -1 VS added with a methane content of around 62%. The nitrogen in the food waste input was on average 8.9 kg tonne -1 . This led to a high ammonia concentration in the digester which may have been responsible for the accumulation of volatile fatty acids that was also observed.

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A pilot-scale comparison of mesophilic and thermophilic digestion of source segregated domestic food waste

Cited by 83 publications

References 10 publications

Effect of a Trace Element Addition Strategy on Volatile Fatty Acid Accumulation in Thermophilic Anaerobic Digestion of Food Waste

Effect of a Trace Element Addition Strategy on Volatile Fatty Acid Accumulation in Thermophilic Anaerobic Digestion of Food Waste

Potential of Using Kitchen Waste in a Biogas Plant

Anaerobic digestion of source-segregated domestic food waste: Performance assessment by mass and energy balance

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