Efficiency of Anaerobic Digestion of Low-Strength Sludge under Different Thermophilic Conditions

2008 ◽  
Vol 1 (5) ◽  
pp. 510-517 ◽  
Author(s):  
Saleh Faraj Magram ◽  
Mahmoud Mohamed Abde Azeem
Keyword(s):  
Anaerobic Digestion ◽  
Thermophilic Conditions ◽  
Low Strength

Biodegradation of PAH and DEHP micro-pollutants in mesophilic and thermophilic anaerobic sewage sludge digestion

2006 ◽  
Vol 53 (8) ◽  
pp. 99-107 ◽  
Author(s):  
T. Benabdallah El-Hadj ◽  
J. Dosta ◽  
J. Mata-Álvarez
Keyword(s):  
Anaerobic Digestion ◽  
Wastewater Treatment Plants ◽  
Economic Cost ◽  
Process Efficiency ◽  
Sludge Digestion ◽  
Thermophilic Conditions ◽  
Polycyclic Aromatic ◽  
Positive Effect ◽  
Process Product ◽  
Micro Pollutants

Anaerobic digestion for the treatment of sludge in wastewater treatment plants has been reported to produce a low organic loaded effluent with an acceptable economic cost. But in the last years, new regulations and the increasing sludge production invite us to find an alternative and/or to improve the process efficiency. Moreover, the use of the effluent as fertilizer in agriculture imposes more restrictions on digestion process product and its micropollutant contents to protect the environment. In this study, a performance of the anaerobic digestion under mesophilic and thermophilic conditions at different hydraulic retention times (HRT) is assessed and the removal efficiencies of two important compounds or family compounds (Polycyclic Aromatic Hydrocarbons, PAH, and Di-2-(Ethyl-Hexyl)-Phthalate, DEHP) are evaluated. A positive effect of thermophilic temperature was observed on both micropollutants' biodegradation. However, HRT effect also had an important role for DEHP and low molecular weighted PAH removal.

Application of ADM1 for the simulation of anaerobic digestion of olive pulp under mesophilic and thermophilic conditions

2006 ◽  
Vol 54 (4) ◽  
pp. 149-156 ◽  
Author(s):  
H. Kalfas ◽  
I.V. Skiadas ◽  
H.N. Gavala ◽  
K. Stamatelatou ◽  
G. Lyberatos
Keyword(s):  
Anaerobic Digestion ◽  
Olive Oil ◽  
Volatile Fatty Acids ◽  
Two Phase ◽  
Solids Concentration ◽  
Thermophilic Conditions ◽  
Maximum Uptake Rate ◽  
Standard Values ◽  
Olive Pulp ◽  
Phase Production

The management of the wastewater originating from olive oil producing industries poses a serious environmental problem. Recently, two-phase production of olive oil has been developed, leading to almost complete elimination of the bulk of the generated wastewater and, is thus regarded as an environmentally friendly technology. However, the main waste stream (olive pulp) is a slurry material characterized by high solids concentration (∼30%), requiring stabilisation before its final disposal. The anaerobic digestion of olive pulp is studied in this work under mesophilic and thermophilic conditions in CSTR-type digesters. The digesters were fed with water-diluted (1:4) olive pulp at an HRT of 20 days and an OLR of 3.94 kg COD m−3 d−1. In order to study the process kinetics, the digesters were subjected to impulse disturbances of different substrates. The IWA anaerobic digestion model was used to simulate the reactors' response. Some key process parameters, such as the specific maximum uptake rate constants and the saturation constants for the volatile fatty acids degradation were estimated and compared with the standard values suggested by the ADM1.

scholarly journals Degradation of Plastics under Anaerobic Conditions: A Short Review

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 109 ◽  
Author(s):  
Xochitl Quecholac-Piña ◽  
María del Consuelo Hernández-Berriel ◽  
María del Consuelo Mañón-Salas ◽  
Rosa María Espinosa-Valdemar ◽  
Alethia Vázquez-Morillas
Keyword(s):  
Anaerobic Digestion ◽  
Short Review ◽  
Anaerobic Conditions ◽  
Experimental Conditions ◽  
Biodegradation Process ◽  
Thermophilic Conditions ◽  
Global Concern ◽  
Useful Life ◽  
Life Options ◽  
Temperature Water

Plastic waste is an issue of global concern because of the environmental impact of its accumulation in waste management systems and ecosystems. Biodegradability was proposed as a solution to overcome this problem; however, most biodegradable plastics were designed to degrade under aerobic conditions, ideally fulfilled in a composting plant. These new plastics could arrive to anaerobic environments, purposely or frequently, because of their mismanagement at the end of their useful life. This review analyzes the behavior of biodegradable and conventional plastics under anaerobic conditions, specifically in anaerobic digestion systems and landfills. A review was performed in order to identify: (a) the environmental conditions found in anaerobic digestion processes and landfills, as well as the mechanisms for degradation in those environments; (b) the experimental methods used for the assessment of biodegradation in anaerobic conditions; and (c) the extent of the biodegradation process for different plastics. Results show a remarkable variability of the biodegradation rate depending on the type of plastic and experimental conditions, with clearly better performance in anaerobic digestion systems, where temperature, water content, and inoculum are strictly controlled. The majority of the studied plastics showed that thermophilic conditions increase degradation. It should not be assumed that plastics designed to be degraded aerobically will biodegrade under anaerobic conditions, and an exact match must be done between the specific plastics and the end of life options that they will face.

Anaerobic digestion of solid animal waste in an accumulation system at mesophilic and thermophilic conditions, start up

2003 ◽  
Vol 48 (4) ◽  
pp. 217-220 ◽  
Author(s):  
H.M. El-mashad ◽  
G. Zeeman ◽  
W.K.P. van Loon ◽  
G.P.A. Bot ◽  
G. Lettinga
Keyword(s):  
Anaerobic Digestion ◽  
Minor Effect ◽  
Mixing Conditions ◽  
Rate Limiting Step ◽  
Start Up ◽  
Accumulation System ◽  
Filling Time ◽  
Thermophilic Conditions ◽  
A Minor ◽  
Rate Limiting

The anaerobic digestion of solid animal wastes has been studied in an accumulation system (AC) at a filling time of 60 days followed by about 50 days batch digestion at 40 and 50°C. Poor mixing conditions during anaerobic digestion of solid wastes promote stratification of the substrate and intermediate products along the reactor height. The effect of layers stratification has also been followed in the AC system. The results showed a pronounced stratification of both CODdis and VFA concentrations along the AC system height. The temperature had a minor effect on the methane yield. The results also showed that methanogenesis was rate limiting in the AC system while the hydrolysis was the rate-limiting step during batch digestion.

Ammonia influence in anaerobic digestion of OFMSW

2009 ◽  
Vol 59 (6) ◽  
pp. 1153-1158 ◽  
Author(s):  
T. Benabdallah El Hadj ◽  
S. Astals ◽  
A. Galí ◽  
S. Mace ◽  
J. Mata-Álvarez
Keyword(s):  
Anaerobic Digestion ◽  
Competitive Inhibition ◽  
Biogas Production ◽  
Gompertz Model ◽  
Ammonia Concentration ◽  
Ion Concentration ◽  
Ammonium Ion ◽  
Municipal Solid Wastes ◽  
Methane Generation ◽  
Thermophilic Conditions

The anaerobic digestion of the organic fraction of municipal solid wastes is taking increasing importance in the recent years. The main problem of some anaerobic digestion process is the large quantity of ammonia that is released, especially when high solid digestion is implemented. A fraction of the supernatant is treated and the remaining is recirculated to maintain the reactor in the optimum solids concentration. The question arising is if this recirculation stream should also be treated to improve biogas production. However, when doing the latter the quantity of ammonia inside the reactor increases too which could lead to inhibit the reactor operation. In this paper it appears that not only free ammonia affects the methanogenic fermentation but also ammonium ion concentration. Biogas production profiles are estimated using the Gompertz model. On the other hand, inhibition constants are fitted using a non-competitive inhibition model equation Thus, 50% inhibition of biomethane production was observed at level of 215 and 468 mg NH3_N/L under mesophilic and thermophilic conditions. However, the methane generation under mesophilic and thermophilic conditions was reduced by 50% when ammonium ion reach concentrations of 3,860 and 5,600 mg NH4+_N/L respectively. Under mesophilic conditions, pH higher than 7 impacted the methanogens bacteria negatively. This threshold pH limit, is variable under thermophilic conditions, depending on the total ammonia concentration.

Anaerobic digestion of mixed microalgae cultivated in secondary effluent under mesophilic and thermophilic conditions

2015 ◽  
Vol 72 (8) ◽  
pp. 1398-1403 ◽  
Author(s):  
Glenda Cea-Barcia ◽  
Gloria Moreno ◽  
Germán Buitrón
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Incubation Temperature ◽  
Secondary Effluent ◽  
Microalgae Culture ◽  
Batch Tests ◽  
Volatile Solids ◽  
Thermophilic Conditions ◽  
Maximum Production Rate ◽  
Mesophilic Conditions

The anaerobic digestion of mixed indigenous microalgae, grown in a secondary effluent, was evaluated in batch tests at mesophilic (35°C) and thermophilic (50°C) conditions. Under mesophilic conditions, specific methane production varied from 178 to 207 mL CH4/g volatile solids (VS) and the maximum production rate varied from 8.8 to 26.1 mL CH4/(gVS day), depending on the type of microalgae culture. Lower methane parameters were observed in those cultures where Scenedesmus represents more than 95% of the microalge. The culture with the lowest digestion performances under mesophilic conditions was studied under thermophilic conditions. The increase in the incubation temperature significantly increased the specific methane production (390 mL CH4/g VS) and rate (26.0 mL CH4/(gVS day)). However, under thermophilic conditions a lag period of 30 days was observed.

scholarly journals The inactivation of a bovine enterovirus and a bovine parvovirus in cattle manure by anaerobic digestion, heat treatment, gamma irradiation, ensilage and composting

1986 ◽  
Vol 97 (1) ◽  
pp. 175-184 ◽  
Author(s):  
H. D. Monteith ◽  
E. E. Shannon ◽  
J. B. Derbyshire
Keyword(s):  
Anaerobic Digestion ◽  
Gamma Irradiation ◽  
Single Cell ◽  
Single Cell Protein ◽  
Cattle Manure ◽  
Cell Protein ◽  
Bovine Enterovirus ◽  
Thermophilic Conditions ◽  
Digested Liquid ◽  
Bovine Parvovirus

SUMMARYA bovine enterovirus and a bovine parvovirus seeded into liquid cattle manure were rapidly inactivated by anaerobic digestion under thermophilic conditions (55°C), but the same viruses survived for up to 13 and 8 days respectively under mesophilic conditions (35°C). The enterovirus was inactivated in digested liquid manure heated to 70°C for 30 min, but the parvovirus was not inactivated by this treatment. The enterovirus, seeded into single cell protein (the solids recovered by centrifugation of digested liquid manure), was inactivated by a gamma irradiation dose of 1·0 Mrad, but the parvovirus survived this dose. When single cell protein seeded with bovine enterovirus or bovine parvovirus was ensiled with cracked corn, the enterovirus was inactivated after a period of 30 days, while the parvovirus survived for 30 days in one of two experiments. Neither the enterovirus nor the parvovirus survived composting for 28 days in a thermophilic aerobic environment when seeded into the solid fraction of cattle manure. It was concluded that, of the procedures tested, only anaerobic digestion under thermophilic conditions appeared to be a reliable method of viral inactivation to ensure the safety of single cell protein for refeeding to livestock. Composting appeared to be a suitable method for the disinfection of manure for use as a soil conditioner.

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