Co-digestion of microalga-bacteria biomass with papaya waste for methane production

2018 ◽  
Vol 78 (1) ◽  
pp. 125-131 ◽  
Author(s):  
Glenda Cea-Barcia ◽  
Jaime Pérez ◽  
Germán Buitrón
Keyword(s):  
Enzymatic Activity ◽  
Municipal Wastewater ◽  
Loading Rate ◽  
High Rate ◽  
Methane Yield ◽  
Organic Loading Rate ◽  
Ammonium Concentration ◽  
Volatile Solid ◽  
Organic Loading ◽  
Total Volatile

Abstract The anaerobic co-digestion of microalga-bacteria biomass and papaya waste (MAB/PW) was evaluated under semi-continuous conditions. Microalgae-bacteria biomass was obtained from a high rate algal pond fed with municipal wastewater and artificially illuminated. The co-digestion of MAB/PW was evaluated using a 1:1 (w/w) ratio and an organic loading rate of 1.1 ± 0.1 g COD/L/d. Enzymatic activity assays of papain were performed in the feeding to determine the activity of this enzyme in the substrate mixture. A methane yield of 0.55 L CH4/gVS and 68% of total volatile solid removal were observed. The volumetric productivity was 0.30 ± 0.03 L CH4/L/d with a methane content of 71%. It was observed that papaya waste was a suitable co-substrate because it maintained a low ammonium concentration, decreasing the risk of inhibition due to ammonia and then increasing the methane yield of the microalgae-bacteria biomass compared to the biomass alone. The pretreatment effect by the addition of papaya waste on the microalgae-bacteria biomass was supported by the papain activity remaining in the substrate.

scholarly journals Concentration of Municipal MBBR Effluent by FO for Resource Recovery: Batch Experiments in Side-Stream Configuration

Membranes ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 278
Author(s):  
Willy Røstum Thelin ◽  
Edvard Sivertsen ◽  
Gema Raspati ◽  
Kamal Azrague ◽  
Herman Helness
Keyword(s):  
Membrane Fouling ◽  
Municipal Wastewater ◽  
Loading Rate ◽  
Resource Recovery ◽  
High Rate ◽  
Organic Loading Rate ◽  
Particle Removal ◽  
Organic Loading ◽  
Particulate Fouling ◽  
Flux Decline

A novel approach for resource recovery includes forward osmosis (FO) as a concentration step in municipal wastewater treatment. The current study investigates different pre-treatment strategies including biological treatment with a moving-bed bioreactor (MBBR) at different loading rates and particle removal by filtration and sedimentation. Membrane performance and recovery potential for energy and nutrients were investigated in laboratory-scale FO experiments in batch mode using pre-treated municipal wastewater as feed and 35 g/L NaCl as a draw solution. Initial water fluxes were in the range of 6.3 to 8.0 L/(m2·h). The baseline fluxes were modelled to account for flux decline due to concentration effects and to enable the prediction of flux decline due to membrane fouling. Fouling-related flux decline varied from 0 to 31%. Both organic fouling and precipitation of CaCO3 and CaHPO4 were identified by using SEM–EDS. High-rate flushing resulted in complete flux recovery under most conditions. Scaling could be avoided by lowering the pH. Two operation strategies were tested to achieve this: (1) applying a bioreactor with a low organic loading rate to achieve high nitrification, and (2) adding a strong acid. A low organic loading rate and the use of additional particle removal were efficient measures that reduced organic/particulate fouling. The recovery potentials for COD and phosphorous in FO concentrate were close to 100%.

scholarly journals A CRITICAL REVIEW ON THE EFFECT OF FEED TO INOCULUM RATIO ON BIOGAS DIGESTION

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
M Kalyani ◽  
Shalini Suran ◽  
P Ramya
Keyword(s):  
Particle Size ◽  
Municipal Wastewater ◽  
Loading Rate ◽  
Synergistic Effects ◽  
Considerable Effect ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Successful Operation ◽  
Start Up ◽  
Biogas Digestion

This paper primarily focuses on the effect of feed to inoculum ratio on biogas digestion; and outlines the various feeds, inoculums, and synergistic effects of the combination of inoculums by referring to the literature. The Start-up of an anaerobic digestion system is highly critical and pivotal for the successful operation of an anaerobic digester. For this purpose, a certain amount of inoculum is added to the digester along with the substrate to provide the necessary microorganisms to initiate the digestion process. The ratio and the type of inoculum used substantially affect the rate of biodegradation and the lag time. The degradation of substrate depends on the concentration of microorganisms. When food waste was considered as the feed it was found that factors such as waste oil content, the addition of alkaline buffer, particle size, organic loading rate had a considerable effect on the feed to inoculum ratio. Studies considering some other feeds such as animal by products from piggery slaughterhouses, poultry slaughterhouse wastes, agro-industrial waste, anaerobically digested sludge obtained from municipal wastewater, and dewatered digestate cake were also compared. Hence, the objective of this study is to offer an integrated view of the appropriate feed and the inoculum under the effect of various other essential parameters. The major performance indicators from this study were found to be particle size of inoculum, organic loading rate, the addition of alkaline buffer, F/I ratio, and structure of inoculum

scholarly journals Anaerobic co-digestion of municipal wastewater sludge and restaurant grease

2011 ◽  
Vol 46 (4) ◽  
pp. 290-299 ◽  
Author(s):  
Zengkai Liu ◽  
Ian D. Buchanan
Keyword(s):  
Municipal Wastewater ◽  
Loading Rate ◽  
Energy Content ◽  
Biogas Production ◽  
Oxygen Demand ◽  
High Energy ◽  
Wastewater Sludge ◽  
Methane Yield ◽  
Organic Loading Rate ◽  
Negative Effect

Co-digestion has drawn much attention because of its potential to increase biogas production among other benefits. Restaurant grease has high energy content and methane production potential and so is a promising substrate for co-digestion with municipal wastewater sludge. Anaerobic co-digestion of municipal wastewater sludge and restaurant grease was investigated at laboratory-scale under mesophilic conditions (37 °C). Increasing the chemical oxygen demand (COD) loading rate of the test digester by 387% (organic loading rate 4.235 kg VS/m3/d) relative to the control digester led to a 467% increase in daily biogas production, a 25.2% increase in methane yield (based on volatile solids (VS) destruction), a 29.8% increase in COD removal and a 27.2% increase in VS reduction. The biogas methane content ranged from 62.6 to 66.2% (v/v). No negative effect of the grease addition was observed in the test digester performance under the conditions investigated. The increases in biogas production and methane yield indicated enhanced digestion performance. In addition, partial alkalinity and pH proved to be good indicators of digester stability.

scholarly journals EFFECT OF ORGANIC LOADING RATE ON THE PERFORMANCE OF ANAEROBIC CO-DIGESTION DIGESTER TREATING FOOD WASTE AND SLUDGE WASTE

2018 ◽  
Vol 56 (2A) ◽  
pp. 37-42
Author(s):  
Dinh Thi Nga
Keyword(s):  
Production Rate ◽  
Food Waste ◽  
Loading Rate ◽  
Biogas Production ◽  
Methane Yield ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Working Volume ◽  
Sludge Waste ◽  
Biogas Production Rate

This research was carried out to evaluate the effect of organic loading rate to the performance of anaerobic co-digestion digester treating organic fraction of food waste (FW) and sludge waste (SW) from wastewater treatment plant. The experiment was conducted in two runs: Run S50, substrate contained 50 % of FW and 50 % of SW in term of volatile solid (VS) concentration; Run S100 (control run) contained 100 % SW in the influent substrate. The experiment was performed in a 3L working volume reactor at ambient temperature with three levels of organic loading rate (OLR) as 2; 4; 6 kgVS/m3/day, the duration of experiment was 18 days for each level of OLR. As results, the average of biogas production rate (BPR) at OLR 2;4;6 kgVS/m3/day,in Run S50 and Run S100 was 390 – 520;  860 – 1220; 1140 - 2440 ml/day and 160 – 300; 560 – 640; 700 - 1400 ml/day, respectively. The maximum methane yield (mlCH4/gVSadded/day) of organic loading rate 2; 4; 6 kgVS/m3/day was 118.96; 326.49; 628.20 for Run S50 and; 58.28; 160.27; 255.54 for Run S100, respectively. In conclusion, Run S50 always produced higher biogas production rate and higher methane yield at all 3 OLR levels. The higer OLR could enhance BPR and methane yield but at OLR 6 kgVS/m3/day made unstable performance and high concentration of COD in the effluent. Therefore, in this experimental conditions it has better operation at OLR under 6 kgVS/m3/day for the stable performance of reactors.

scholarly journals Anaerobic Digestion of Animal Manure and Influence of Organic Loading Rate and Temperature on Process Performance, Microbiology, and Methane Emission From Digestates

2021 ◽  
Vol 9 ◽  
Author(s):  
Karin Ahlberg-Eliasson ◽  
Maria Westerholm ◽  
Simon Isaksson ◽  
Anna Schnürer
Keyword(s):  
Methane Production ◽  
Loading Rate ◽  
Energy Content ◽  
Biogas Production ◽  
Poultry Manure ◽  
Methane Emissions ◽  
Economic Benefits ◽  
Methane Yield ◽  
Organic Loading Rate ◽  
Organic Loading

Biogas production from manure is of particular value in regard of lowering greenhouse gas emissions and enhancing nutrient re-circulation. However, the relatively low energy content and the characteristics of manure often result in low degradation efficiency, and the development of operating strategies is required to improve the biogas yield and the economic benefits. In this study, the potential to enhance the performance of two full-scale biogas plants operating with cattle manure, in mono-digestion or combined with poultry manure, was investigated. Four continuously fed laboratory-scale reactors were operated in sets of two, in which the temperature in one reactor in each set was increased from 37–42°C to 52°C. The potential to increase the capacity was thereafter assessed by increasing the organic loading rate (OLR), from ca 3 to 5 kg volatile solids (VS)/ m3 and day. The processes were evaluated with both chemical and microbiological parameters, and in addition, the residual methane potential (RMP) was measured to evaluate the risk of increased methane emissions from the digestate. The results showed that both processes could be changed from mesophilic to themophilic temperature without major problems and with a similar shift in the microbial community profile to a typical thermophilic community, e.g., an increase in the relative abundance of the phylum Firmicutes. However, the temperature increase in the reactor co-digesting cattle and poultry manure caused a slight accumulation of fatty acids (2 g/l) and reduced the specific methane production, most likely due to ammonia inhibition (0.4–0.7 g NH3/l). Still, during operation at higher OLR, thermophilic as compared to mesophilic temperature slightly increased the methane yield and specific methane production, in both investigated processes. However, the higher OLR decreased the overall degree of degradation in all processes, and this showed a positive correlation with increased RMP values. Chemical analyses suggested that high RMP values (40–98 Nml gVS−1) were related to the degradation of cellulose, hemicellulose, and volatile fatty acid enriched in the digestate. Conclusively, increased temperature and load can increase the methane yield from manure but can result in less efficient degradation and increased risks for methane emissions during storage and handling of the digestate.

Start-Up Performances of High-Solid Anaerobic Digestion of Sewage Sludge under Mesophilic Condition

2011 ◽  
Vol 356-360 ◽  
pp. 2020-2026 ◽  
Author(s):  
Ni Na Duan ◽  
Bin Dong ◽  
Qun Biao He ◽  
Xiao Hu Dai
Keyword(s):  
Sewage Sludge ◽  
Loading Rate ◽  
Sharp Decrease ◽  
Total Solid ◽  
Methane Yield ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
High Solid ◽  
Stirred Tank Reactors ◽  
Start Up

High-solid anaerobic digestions of sewage sludge were investigated in completely stirred tank reactors (CSTR) at 35±1°C. The total solid (TS) concentrations of the sludge fed to the reactors were designed at 10%, 15% and 20% respectively after start-up periods. By start-up period is meant the TS concentration of the substrate in the reactor has not reached its designed level. Special attention was paid to the effect of organic loading rate (OLR), TS concentration, and ammonia inhibition on methane yield, volatile solid (VS) reduction and volatile fatty acid (VFA) concentration during the start-up periods. Experimental results showed that no evident inhibition of TS or ammonia was found as long as the concentration of TS was below 10% or the concentration of ammonia-N was below 2000 mg/l. Digestion at TS concentration of 12.5%-14.8% was slightly influenced by ammonia at concentration of 3200-3800 mg N/l. As the TS concentration was above 14.8%, the ammonia-N concentration of 3500-3800 mg/l showed evident inhibition on methanogetic activity, leading to sharp decrease of methane yield and methane content. After start-up, the methane yields at feeding TS of 10%, 15%, and 20% at OLR of 3.0 kg VS m-3d-3 were 0.221, 0.248 and 0.177 l CH4 g-1VSadded-1 d-1, and the VS reduction were 33%, 39.5% and 40%, respectively.

scholarly journals Effect of increasing the organic loading rate on the co-digestion and mono-digestion of cattle slurry and maize

2012 ◽  
Vol 66 (11) ◽  
pp. 2336-2342 ◽  
Author(s):  
M. Cornell ◽  
C. J. Banks ◽  
S. Heaven
Keyword(s):  
Loading Rate ◽  
Laboratory Scale ◽  
Methane Yield ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Cattle Slurry ◽  
Biogas Yield ◽  
Loading Rates ◽  
Volatile Solids ◽  
Rate Of Loading

Co-digestion of cattle slurry and maize has been shown to have benefits for both, improving the biogas yield of the slurry and stability of digestion of the maize. The effect of increasing the total loading rate from 3 to 6 g VS l–1 day–1 on the co-digestion of cattle slurry and maize, mixed at equal volatile solids volumes, was investigated in laboratory-scale continuously stirred digesters. These were compared with similar digesters evaluating the increase of 1.5 to 3 g VS l−1 day−1 loading rates of slurry and maize digested separately. Compared with mono-digestion of the substrates, where the digestion of maize failed at loading rates greater than 2.5 g VS l−1 day−1, the co-digestion of cattle slurry and maize was feasible at all the loading rates tested with an increase in the volumetric methane yield occurring with loading rate. Even at the lowest rate of loading, the addition of equal amounts of volatile solids of maize to slurry leads to an increase in volumetric methane yield of 219%.

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