The thermophilic anaerobic digestion process

Buhr, H. O.; Andrews, John

doi:10.1016/0043-1354(77)90118-x

Cited by 174 publications

(76 citation statements)

References 9 publications

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“…If Figure 3 and 4 is compared the decomposition phase as expected is much faster under thermophilic conditions than under mesophilic conditions. This faster decomposition phase of sewage sludge under thermophilic digestion is a well-known conclusion and has been shown by Buhr and Andrews (1977).…”

Section: Resultsand Discussionmentioning

confidence: 87%

Co-digestion of cultivated microalgae and sewage sludge from municipal waste water treatment

Olsson

Feng

Ascue

et al. 2014

Bioresource Technology

113

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The demand for biogas is continuously growing and the biogas substrate, such as food waste, may soon become limited and it is therefore important for biogas producers to expand the range of substrates. One way can be to use microalgae in co-digestion with sewage sludge.The present study explores the possibilities to use harvested microalgae from Lake Mälaren, as a co-substrate to sewage sludge in biogas production under mesophilic and thermophilic conditions. The aim is to investigate if codigestion of microalgae and sewage sludge is more efficient for biogas production compared using the sludge alone. The study has been carried out as a BMP-experiment (Biochemical Methane Potential) in batch fermentation bottles. The substrate was undigested sludge where 0%, 12 %, 25 % and 37 % were replaced with the cultivated microalgae. The results showed that the use of an algae/bacteria community, cultivated in prior to digestion, can serve as a biomass substrate for biogas production together with municipal wastewater sludge. Co-digestion of microalgae and sewage sludge can be more efficient for biogas production compared to using the sludge alone under mesophilic conditions. It can also be concluded that thermophilic co-digestion between the microalgae and sludge give lower biochemical methane potential.

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Section: Resultsand Discussionmentioning

confidence: 87%

Co-digestion of cultivated microalgae and sewage sludge from municipal waste water treatment

Olsson

Feng

Ascue

et al. 2014

Bioresource Technology

113

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“…The fast, initial release of carbon dioxide is probably partly attributable to a pH decrease due to VFA in the feed [24] and partly to fast hydrolysis and fermentation of dissolved organic matter during acidogenesis and acetogenesis. The slower release of carbon dioxide could be attributable to the slower continuous processes of hydrolysis of less readily degradable organic matter and methanogenesis.…”

Section: Rate Constants Of Carbon Dioxide Formation (Kc1 and Kc2)mentioning

confidence: 99%

Determination of Methane and Carbon Dioxide Formation Rate Constants for Semi-Continuously Fed Anaerobic Digesters

2015

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Abstract:To optimize commercial-scale biogas production, it is important to evaluate the performance of each microbial step in the anaerobic process. Hydrolysis and methanogenesis are usually the rate-limiting steps during digestion of organic waste and by-products. By measuring biogas production and methane concentrations on-line in a semi-continuously fed reactor, gas kinetics can be evaluated. In this study, the rate constants of the fermentative hydrolysis step (kc) and the methanogenesis step (km) were determined and evaluated in a continuously stirred tank laboratory-scale reactor treating food and slaughterhouse waste and glycerin. A process additive containing Fe 2+ , Co 2+ and Ni 2+ was supplied until day 89, after which Ni 2+ was omitted. The omission resulted in a rapid decline in the methanogenesis rate constant (km) to 70% of the level observed when Ni 2+ was present, while kc remained unaffected. This suggests that Ni 2+ mainly affects the methanogenic rather than the hydrolytic microorganisms in the system. However, no effect was initially observed when using conventional process monitoring parameters such as biogas yield and volatile fatty acid concentration. Hence, formation rate constants can OPEN ACCESSEnergies 2015, 8 646 reveal additional information on process performance and km can be used as a complement to conventional process monitoring tools for semi-continuously fed anaerobic digesters.

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“…Past experiences and literature reviews illustrate that a mesophilic range of temperature is the most suitable range for anaerobic conditions, as lower temperature inhibits microbial activities, while elevated (thermophilic) temperature gives rise to high endogenous death of microbes (Buhr et al 1977;Switzenbaum et al 1980;Kennedy et al 1982;Henze et al 1983;Grin et al 1985). Therefore, the temperature was kept constant at a mesophilic range by placing water heating jackets around the reactor.…”

Section: Start-up Of the Reactormentioning

confidence: 99%

Assessment of the Treatment of Textile Mill Effluent Using UASB Reactor

Arshad

Hashim

Kashif

et al. 2011

AJSTD

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ASEAN J. Sci. Technol. Dev., 28(2): 139 -150 Pakistan is facing acute water deficiency, its water resources have been declining day by day on account of diversified environmental and erroneous water management issues. The available water is being contaminated at a deplorable rate owing to the dumping of untreated domestic and industrial effluent together with agricultural/surface runoff into the receiving waterways. Clean drinking water is therefore only accessible to 18% of its population and the rest of the population are getting polluted drinking water, as designated by the required WHO standards (PCRWR 2005). Moreover, it is an admitted truth that Pakistan has a deficient energy sector despite the fact that it has ample potential for its production. The energy supply deficiency also applies to the electricity sector. Bio-gas is however playing a key role in this sector, which is approximately equal to 37% of the total energy production. Since, it's the most cost-effective and environmentally friendly source of energy, it requires more awareness and consideration for it to undertake the resolution of the energy crises Assessment of the Treatment of Textile Mill EffluentUsing UASB Reactor This study was designed to evaluate the feasibility of the treatment of actual textile mill effluent using a upflow anaerobic sludge blanket (UASB) reactor. The main objective of this study was to generate design aids; in terms of organic loading rate (OLR), hydraulic retention time (HRT) versus chemical oxygen demand (COD) and colour removal in the textile effluent using a UASB reactor at neutral pH and constant mesophilic temperature. The COD, colour and total suspended solids concentration of the textile wastes used in the study were analyzed as 5440 mg/l, 3280 mg/l, 2320 units and 955 mg/l, respectively. The UASB reactor was started up by gradually increasing the OLR from 0.2 kg-COD/m 3 -day to 2.6 kg-COD/m 3 -day in order to prevent an organic shock to the reactor. Similarly, the hydraulic retention time (HRT) was slowly reduced from 58 h to 8 h to prevent the wash-out of sludge from the reactor. It was observed that more than 80% of COD and colour could be effectively removed at an OLR of 2.2 kg-m 3 /d and HRT of 20 h. At optimum operating conditions, the effluent volatile fatty acid concentration was observed to be 430 mg/l. The average biogas production observed during this study was 0.34 l/g-COD removed and it was composed of 58% methane. During the course of maturity of granular sludge, its effective size and settling velocity were observed to increase exponentially as 0.261e 0.051x and 1.91e 0.017x respectively. The overall observed biomass yield (Y obs ) for the experimental period was calculated as 0.049 g-VSS/g-COD rem . This study suggests that the use of a UASB reactor for textile mill effluent is a fairly feasible and viable option.

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The thermophilic anaerobic digestion process

Cited by 174 publications

References 9 publications

Co-digestion of cultivated microalgae and sewage sludge from municipal waste water treatment

Co-digestion of cultivated microalgae and sewage sludge from municipal waste water treatment

Determination of Methane and Carbon Dioxide Formation Rate Constants for Semi-Continuously Fed Anaerobic Digesters

Assessment of the Treatment of Textile Mill Effluent Using UASB Reactor

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