The Composting Treatment of Residue from Biological Municipal Waste Anaerobic Digestion

2010 ◽  
Vol 129-131 ◽  
pp. 703-707 ◽  
Author(s):  
Lei Feng ◽  
Run Dong Li
Keyword(s):  
Anaerobic Digestion ◽  
Mass Loss ◽  
Methane Concentration ◽  
Gas Production ◽  
Municipal Waste ◽  
High Solids ◽  
Biodegradation Rate ◽  
Fuel Production ◽  
Digestive Juice ◽  
Compost Quality

The high-solids anaerobic digestion of biological municipal waste (BMW) produces both a valuable fuel production (methane) and an anaerobic digestion residue. Compost technology was chosen to treat with anaerobic digestion residue and the conclusion was. 1) The anaerobic digestion of the bio-waste as a whole worked fine during the stabilization stage, the maximum daily gas production happened on the 125th day, the maximum was 91.86L/d and TS concentration in the digestive juice was14.78%, methane concentration was about 50-55%, HRT was 20 days and the biodegradation rate was 65.28%;2) The temperature of AD residue compost entered the thermophilic phase(55°C) on day 3 of composting, lasted at least 3days, the changes in pH followed the same trend with a rise from 6.18 to 7.26 on the 14th day, he final mass loss was 30.12%, which resulted in the compost quality higher than innocuity criteria.

Gasification as an optimum alternative for the sludge management

2011 ◽  
Vol 6 (4) ◽  
Author(s):  
C. Peregrina ◽  
J. M. Audic ◽  
P. Dauthuille
Keyword(s):  
Power Generation ◽  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Combined Heat And Power ◽  
Gas Production ◽  
Waste Reduction ◽  
Fluidised Bed ◽  
Sludge Management ◽  
Gas Cleaning ◽  
Cleaning System

Assimilate sludge to a fuel is not new. Sludge incineration and Combined Heat and Power (CHP) engines powered with sludge-derived anaerobic digestion gas (ADG) are operations widely used. However, they have a room of improvement to reach simultaneously a positive net power generation and a significant level of waste reduction and stabilization. Gasification has been used in other realms for the conversion of any negative-value carbon-based materials, that would otherwise be disposed as waste, to a gaseous product with a usable heating value for power generation . In fact, the produced gas, the so-called synthetic gas (or syngas), could be suitable for combined heat and power motors. Within this framework gasification could be seen as an optimum alternative for the sludge management that would allow the highest waste reduction yield (similar to incineration) with a high power generation. Although gasification remains a promising route for sewage sludge valorisation, campaigns of measurements show that is not a simple operation and there are still several technical issues to resolve before that gasification was considered to be fully applied in the sludge management. Fluidised bed was chosen by certain technology developers because it is an easy and well known process for solid combustion, and very suitable for non-conventional fuels. However, our tests showed a poor reliable process for gasification of sludge giving a low quality gas production with a significant amount of tars to be treated. The cleaning system that was proposed shows a very limited removal performance and difficulties to be operated. Within the sizes of more common WWTP, an alternative solution to the fluidised bed reactor would be the downdraft bed gasifier that was also audited. Most relevant data of this audit suggest that the technology is more adapted to the idea of sludge gasification presented in the beginning of this paper where a maximum waste reduction is achieved with a great electricity generation thanks to the use of a “good” quality syngas in a CHP engine. Audit show also that there is still some work to do in order to push sludge gasification to a more industrial stage. Regardless what solution would be preferred, the resulting gasification system would involve a more complex scenario compared to Anaerobic Digestion and Incineration, characterised by a thermal dryer and gasifier with a complete gas cleaning system. At the end, economics, reliability and mass and energy yields should be carefully analysed in order to set the place that gasification would play in the forthcoming processing of sewage sludge.

A Mathematical Model for the Anaerobic Digestion Process Applied to a Mixture of Night Soil and Septic Tank Sludge

1986 ◽  
Vol 18 (7-8) ◽  
pp. 239-248 ◽  
Author(s):  
Sung Ryong Ha ◽  
Dwang Ho Lee ◽  
Sang Eun Lee
Keyword(s):  
Mathematical Model ◽  
Anaerobic Digestion ◽  
Biomass Concentration ◽  
Gas Production ◽  
Septic Tank ◽  
Volatile Acid ◽  
Hydraulic Residence Time ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Proposed Model

Laboratory scale experiments were conducted to develop a mathematical model for the anaerobic digestion of a mixture of night soil and septic tank sludge. The optimum mixing ratio by volume between night soil and septic tank sludge was found to be 7:3. Due to the high solids content in the influent waste, mixed-liquor volatile suspended solids (MLVSS) was not considered to be a proper parameter for biomass concentration, therefore, the active biomass concentration was estimated based on deoxyribonucleic acid (DNA) concentration in the reactor. The weight ratio between acidogenic bacteria and methanogenic bacteria in the mixed culture of a well-operated anaerobic digester was approximately 3:2. The proposed model indicates that the amount of volatile acid produced and the gas production rate can be expressed as a function of hydraulic residence time (HRT). The kinetic constants of the two phases of the anaerobic digestion process were determined, and a computer was used to simulate results using the proposed model for the various operating parameters, such as BOD5 and volatile acid concentrations in effluent, biomass concentrations and gas production rates. These were consistent with the experimental data.

332 Effect of Chemical and Biological Preservatives on in vitro Fermentation and Methane Production of Ensiled and Aerobically Exposed Wet Brewer’s Grains

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 182-182
Author(s):  
Marjorie A Killerby ◽  
Diego Zamudio ◽  
Kaycee Ames ◽  
Darren D Henry ◽  
Thomas Schwartz ◽  
...  
Keyword(s):  
Methane Production ◽  
Production System ◽  
Methane Concentration ◽  
Block Design ◽  
Gas Production ◽  
Sodium Lignosulfonate ◽  
In Vitro Fermentation ◽  
Randomized Complete Block Design ◽  
System Data

Abstract This study evaluated the effects of preservatives on the in vitro fermentation measures of wet brewer’s grain (WBG) silage at different stages of storage. Treatments (TRT) were sodium lignosulfonate at 1% (NaL1) and 2% (NaL2; w/w of fresh WBG), propionic acid (PRP; 0.5% w/w of fresh WBG), a combination inoculant (INO; Lactococcus lactis and Lactobacillus buchneri each at 4.9 log cfu/fresh WBG g), and untreated WBG (CON). WBG (Fresh) were packed into 8.8 L mini-silos and stored for 60 d at 21°C (Ensiled), then they were opened and aerobically exposed for 10d (AES). Samples from each stage of storage (STG; Fresh, Ensiled and AES) were analyzed for in vitro ruminal digestibility (24 h).Gas kinetics were recorded using the Ankom RF Gas Production System. Data were analyzed as a randomized complete block design (5 blocks) with a 5 (TRT) × 3 (STG) factorial arrangement. Apparent in vitro DM digestibility (DMD) decreased across STG, (51.5, 47.2 and 40.9 for Fresh, Ensiled and AES, respectively) and increased for NaL1, NaL2 and PRP (~47.8) vs. CON (43.0 ± 2.12%). PRP increased apparent in vitro OM digestibility (OMD) when Ensiled (54.5) and NaL2 increased it for AES (47.1) vs CON (46.3 and 39.9 ± 1.73%, respectively). The asymptotic maximal (M) and rate (k) of gas production decreased across STG (214.6, 181.5, 155.1 and 14.6, 12.6, and 9.8, for Fresh, Ensiled and AES, respectively). PRP increased (200.0) and NaL1 decreased (169.3) M vs. CON (183.9± 7.81ml/incubated DM g), while NaL1 and NaL2 (~11.4) decreased k vs. CON (13.4 ± 0.85%/h). Methane concentration and yield were higher in Fresh vs. other STG (0.94 vs. ~0.84 ± 0.07mM and 0.27 vs. ~0.23 ± 0.03mmol/g fermented OM). Spoilage of WBG decreases fermentability and methane production while PRP and NaL improve digestibility with the former also increasing M and k.

Biological nutrient removal wastewater treatments and sewage sludge anaerobic mesophilic digestion performances

2002 ◽  
Vol 46 (10) ◽  
pp. 199-208 ◽  
Author(s):  
D. Bolzonella ◽  
L. Innocenti ◽  
F. Cecchi
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Economic Assessment ◽  
Gas Production ◽  
Anaerobic Digester ◽  
Biological Nutrient Removal ◽  
Energetic Balance ◽  
Mesophilic Digestion ◽  
The Difference ◽  
Energy Balances

The paper deals with the performances of the mesophilic anaerobic digestion treatment of sewage sludge from a full scale BNR process without primary settling (nominally 300,000 PE). A relation between the activated sludge observed yields, Yobs, and the anaerobic digester performance was preliminarily found: for values of Yobs of 0.25 kgVSS/kgCOD the anaerobic digester specific gas production showed the best performances (0.22 m3/kgVSfed). This has to be confirmed with wider future studies. It was also shown the level of sludge pre-thickening to be reached for the self-sustaining warming of the digester also in wintertime. According to the energetic balance and to a comparison with an aerobic stabilisation process, it was pointed out as when a co-generation unit for heat and energy production was introduced about 3.4 kWh/PE y of energy were produced in the anaerobic digestion process. On the other hand, 4.3 kWh/PE y were spent if an aerobic stabilisation process was applied. The economic assessment, carried out on the basis of the energy balances, showed that the anaerobic digestion is always economically advantageous if compared to aerobic stabilisation processes, also for small WWTPs. According to the energetic evaluations an environmental balance was assessed, in terms of CO2 emissions. The difference between anaerobic and aerobic processes was about 5.3 kgCO2/PE y in favour of anaerobic processes application.

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