Improvement of Methane Production from Corn Stalk for Whole Slurry Anaerobic Co-digestion Under Hydrothermal Wastewater Pretreatment

Corn stalk hydrothermal wastewater(CSHW)was used as a pretreatment for whole-slurry anaerobic co-digestion instead of conventional acid pretreatment.CSHW pretreatment was conducted at 20℃,35℃and 50℃for 3,6 and 9 h,after which all experimental groups were digested at 35℃for 24 days.This pretreatment method efficiently broke the lignocellulose structure of the corn stalk.Different from the volatile fatty acids(VFAs)content,the pH and RS contents were relatively higher than those of the control during the pretreatment process.Furthermore,the highest methane production[185.03 mL•g-1 VS(volatile solid)]was achieved at 55.46%under 35℃in 6 h,which was higher than that of the normal corn stalk anaerobic digestion.The VFAs contents and pH increased compared to CK upon the addition of NaOH to adjust pH,and the RS content also increased slightly due to the degradability of lignocellulose during the whole-slurry anaerobic co-digestion.This work provided a potential method to sustainably treat wastewater and improve fermentation performance.

Biogas Production from Various Typical Organic Wastes Generated in the Region of Cantabria (Spain): Methane Yields and Co-Digestion Tests

Batch trials were carried out to determine the methane potential yields of some typical organic wastes generated in the region of Cantabria (Spain): cocoa shell, cheese whey and sludges from dairy industry. Anaerobic co-digestion trials of these wastes with dairy manure were also investigated in batch at 35℃. Cheese whey obtained similar methane yields than dairy manure, between 17.5 and 19.3 L CH4kg-1 cheese whey compared with 18.0 L CH4kg-1 manure. Methane yields of various sludge samples collected from wastewater treatment facilities of dairy industries were influenced by its origin. Sludge samples from fat separation devices were the most productive in terms of specific methane yields compared with biological sludge from an aerobic reactor. Sludge samples from fat separator reached specific methane productivities of 350 and 388 L CH4kg-1 VS (10.5 and 24.1 L CH4kg-1 sludge), whereas biological sludge yielded 125 L CH4kg-1 VS (12.6 L CH4kg-1 sludge). The methane potential of sludge samples was influenced by solids content. Cocoa shell resulted to be an interesting waste for anaerobic digestion due to its high VS content, yielding 195 L CH4kg-1 cocoa shell. It is a waste that can considerably improve methane yields in anaerobic co-digestion with dairy manure. However, at proportions of 10% cocoa shell, the process was hindered by hydrolysis of particulate matter. Anaerobic digestion at higher temperatures (thermophilic range) could be a better option for this kind of waste. Co-digestion of 5% cocoa shell with 35% dairy sludge and 60% dairy manure resulted in 80.5% higher methane production compared to anaerobic digestion of dairy manure alone.

Study on anaerobic co-digestion with distillery wastewater to improve the dewatering property of the secondary sludge

This paper presents the results obtained for the effluent dewatering properties of anaerobic digestion of secondary sludge （SS） and anaerobic co-digestion of mixture of this sludge with the distillery wastewater （DW） under thermophilic （55±1 ℃）, 5 L of working volume, three parallel lab-scale conditions. Its mixtures were prepared with a DW content of 25%and 50% and the C/N ratios of mixtures are 13.1 and 17.6, respectively. The effluent dewatering properties were evaluated under stable conditions which the biogas yield and the effluent pH were steady. The natural settleability, biogas yield, centrifugal dewatering, centrifugal supernatant turbidity and specific resistance filtration （SRF） were investigated. The results showed that the effluent dewatering properties of anaerobic co-digestion of mixtures between SS and DW were better than that of anaerobic digestion of SS alone. In the anaerobic digestion system with the feed were SS, mixture of SS and a DW content of 25%and 50% in order, the net biogas yield of secondary sludge in ADSA,ADSB and ADSC were 0.42 0.507 and 0.511 m3 biogass/kg.VS.d ; compared with the biogas yield in anaerobic digestion system A （ADSA）, the biogas yield in anaerobic digestion system B （ADSB） and anaerobic digestion system C （ADSC） had been increased by more than 20% respectively; the SRF of three digested sludge are（were） from 6.8×10^13, 1. 1×10^13 to 5.1×10^12 m/Kg, natural settling rates of 12 h are 26, 37 and 56% and that of 24 h are 32%, 45% and 59% respectively; the centrifugal dewatering rate of 3 min at speed of 1000 rpm were 16%, 31% and 51% respectively; the turbidity of centrifugal supernatant were 804, 754 and 678FTU simultaneously.

Co-digestion Of Olive Mill Wastewater and Swine Manure Using Up-Flow Anaerobic Sludge Blanket Reactor for Biogas Production

Swine wastewater (SW) and olive mill wastewater (OMW) are two problematic wastes that have become major causes of health and environmental concerns. The main objective of the current work was to evaluate the efficiency of the co-digestion strategy for treatment of SW and OMW mixtures. Mesophilic batch reac-tors fed with mixtures of SW and OMW showed that the two adapted sludges Gadot and Prigat exhibited the best COD removal capacity and biogas production;therefore both were selected to seed up-flow anaerobic sludge blanket (UASB) continuous reactors. During 170 days of operation, both sludges Gadot and Prigat showed high biodegradation potential. The highest COD removal of 85-95% and biogas production of 0.55 L?g-1 COD were obtained at a mixture consisting of 33% OMW and 67% SW. Under these conditions, an organic load of 28,000 mg?L-1 COD was reduced to 1,500-3,500 mg?L-1. These results strongly suggest that co-digestion technology using UASB reactors is a highly reliable and promising technology for wastewater treatment and biogas production.

Characterization of Digestates from Anaerobic Co-Digestion of Manioc Effluent, Human Urine and Cow Dung

This study focused on the characterization of digestates resulting from anaerobic digestion of manioc effluents from attiéké factories. Two types of digestate were characterized, one consisting of manioc effluent + urine and another composed of manioc effluent + urine + cow dung. As a result, these residues of bio-digestion rich in nutrients (NPK) can be used as agricultural fertilizer. Moreover, the determination of some microorganisms and heavy metals digestates allowed to better appreciate its fertilizing quality. These parameters remained in accordance with the quality standards of a digestate prescribed. These results show that digestates from anaerobic co-digestion of manioc effluents, urine and cow dung can be used without fear as an agricultural biofertilizer.

Anaerobic Co-digestion Process Efficiency Estimation in Phases as an Alternative for Municipal Waste Treatment

The incorrect disposal of the waste generated in the municipalities contributes to water and soil contamination,resulting in a real concern in order to find an adequate disposal as well as obtain by-products that can be used to reduce CO2 emissions.Anaerobic digestion turns out to be the most efficient treatment,both in environmental and economic terms.The objective of this study is to evaluate the anaerobic co-digestion process in phases as an alternative for the treatment of municipal waste:sludge from water treatment plants and the biodegradable part of Municipal Solid Waste(MSW),for three HRTs(Hydraulic Retention Times).Testing results show up a max elimination of 70.68%in VS(Volatile Solids)and 74.01%in COD(Chemical Oxygen Demand).With these percentages of elimination on average,15.96 L/d of biogas was produced,for each kg of COD eliminated 0.56 m3 of biogas was produced and for each kg of SV 0.85 m3 and methane of 50.10%.

The Survival of Cefazolin Resistant Bacteria in Thermophilic Co-digestion of Dairy Manure and Waste Milk

Recent studies have suggested that there may be a link between the use of in-feed antibiotics and the prevalence of antibiotic-resistant bacteria in human infections. It is believed that anaerobic digestion is a potent method to reduce the antibiotic resistant bacteria present in waste from concentrated animal feeding operations. Cefazolin is a β-1actam antibiotic that is frequently used to treat the cows with mastitis in the Obihiro University herd. Disposal of untreated milk containing cefazolin residues promotes the occurrence of cefazolin resistant bacteria in the vicinity of farm, thus the objective of this study was to investigate the survival of antibiotic resistant bacteria in co-digestion of dairy manure and waste milk obtained from cows treated for mastitis with cefazolin under thermophilic conditions （55 ~C）. Cow manure, digested slurry and waste milk （cefazolin residue concentration 2.17 mg/L） were used as the materials in order to have three digester contents; 100% slurry, 50% slurry ＋ 50% manure and 50% slurry ＋ 45% manure ＋ 5% waste milk. The experiment was carried out using batch digesters （1 L） with active volume of 800 mL at 55 ℃ for 20 days to determine the survival of cefazolin resistant bacteria and to observe the digester performance by determining the bio gas and methane yield using gas chromatpgrapby. Dilution plate method was used to determine the population densities of total and cefazolin resistant bacteria at 0, 10th and 20th day of digestion. Total and cefazolin resistant bacterial counts were reduced with time by several orders until 10th day of digestion and those were almost similar at day 20th. Highest daily biogas and methane yield were observed in the digester contained slurry, manure and waste milk during early digestion period （until 5th day）. The results suggest that thermophilic co-digestion of dairy manure and waste milk would be a suitable technology for reducing antibiotic （cefazolin） resistant bacteria while obtaining better digester performance.

Biogas Production from the Co-Digestion of Cornstalks with Cow Dung and Poultry Droppings

The Anaerobic digestion of Corn Stalk (CS) with Cow Dung (CD) and Poultry Droppings (PD) was investigated. Batch mono-digestion and Co-digestion experiments were performed with initial total solid loading of 37.5%. The main objective of this work was to investigate the biogas yield at different CS to CD ratios and CS to PD ratios. Results show that the highest Cumulative Gas Yield (CGY) of 6833 mL/g of biomass was achieved in 21 days for CS-CD ratio of 2:1. Similarly high CGY of 6107 mL/g, 6100 mL/g and 5333 mL/g were obtained for CS-PD ratio of 2:1, CS-CD ratio of 1:1 and CS-PD ratio of 1:1 respectively. It is concluded that co-digestion of Cow dung or poultry droppings is beneficial for improving bio-digestibility and Biogas yield from corn stalk. The results of this work provide useful information to improve the efficiency of co-digestion of CS with CD and PD under anaerobic conditions.

Bioelectricity from Anaerobic Co-Digestion of Organic Solid Wastes and Sewage Sludge Using Microbial Fuel Cells (MFCs)

Recently microbial fuel cells (MFCs) have been considered as an alternative power generation technique by utilizing organic wastes. In this study, an experiment was carried out to generate bioelectricity from co-digestion of organic waste (kitchen waste) and sewage sludge as a waste management option using microbial fuel cell (MFC) in anaerobic process. A total of five samples with different sludge-waste ratio were used with zinc (Zn) and cupper (Cu) as cell electrodes for the test. The trends of voltage generation were different for each sample in cells such as 350 mV, 263 mV, 416 mV maximum voltage were measured from sample I, II and III respectively. It was observed that the MFC with sewage sludge showed the higher values (around 960 mV) of voltages with time whereas 918 mV obtained with organic waste. Precisely comparing cases with varying the organic waste and sewage sludge ratio helps to find the best bioelectricity generation option. Using MFCs can be appeared as the solution of electricity scarcity along the world as an efficient and eco-friendly manner as well as organic solid waste and sewage sludge management.

Anaerobic Co-Digestion of Fish Processing Waste with Cow Manure and Waste of Market (Rests of Fruits and Vegetables): A Lab Scale Batch Test

The aim of this work was to use fish processing waste (FW) as main substrate for anaerobic digestion. To enhance the biogas production of FW, co-digestion was done with two other substrates: cow dung (CD) and waste of market (MW). Batch test was carried out in an 1 L glass digester in a temperature controlled chamber at 38°C. The following mixtures were carried out: FW with CD respectively at different ratios 100:0% (A), 80:20% (B) and 60:40% (C);FW with MW at the following ratio 80:20% (D);FW with CD and MW respectively at these ratios 80:10:10% (F) and 60:20:20% (G). The biogas produced was measured using a milligas counter® and the volume of gas was recorded. The gas composition was determined using gas chromatography. With a pH stable for raw substrates and mixtures, TS and VS (%TS) contents for FW were respectively 31.01% and 91.55%. Between 3 to 13 days of experimentation, the highest flow rate was observed. The percentage of methane was more important for mixtures B and D, 61% and 59% respectively. pH and VOA/TIC were stable at the end of the batch test for all mixtures, meaning that the organic matter was already well digested. The highest values of Volatile Solid Removal (VSR) were found for mixtures C, D, F and G. Therefore, the promising mixtures for next experimentations in large scale are B and D.

Phylogenetic Analysis of Anaerobic Co-Digestion of Animal Manure and Corn Stover Reveals Linkages between Bacterial Communities and Digestion Performance

Over 3 million tons of manures are produced annually in the United States and pose environmental and health risks if not remediated. Anaerobic digestion is an effective method in treating organic wastes to reduce environmental impacts and produce methane as an alternative energy. Previous studies suggested that optimization of feed composition, hydraulic retention time, and other operational conditions can greatly improve total solids removal and increase methane productivity. These environmental factors improve functionality by altering the microbial community structure but explicit details of how the bacterial community shifts are poorly understood. Our investigations were conducted to investigate the relationship between environmental factors, microbial community structure and bioreactor efficiency by using metagenomic analysis of the microbial communities. Our results indicated that the bioreactor with the greatest methane production, digestion efficiency and reduced levels of E. coli/Shigella had a distinctive community structure at the genus level with unique and abundant uncultivated strains of Bacteroidetes. Moreover the same bioreactor was enriched in Aminomonas paucivorans and Clostridia populations that can utilize secondary metabolites produced during cellulose/hemicellulose degradation to generate hydrogen and acetate. Hence specific digestion conditions that enrich for these populations may provide a route to the optimization of co-digestion systems and control the variability in reactor performance.

Effect of goethite on anaerobic co-digestion process of corn straw and algae biomass

1 Introduction Recently the demand for fossil fuel has grown significantly with the rapid development of the Chinese economy.Renewable energy was developed to replace traditional fossil fuels,which would decrease the

Effect of Variation in Co-Digestion Ratios of Matooke, Cassava and Sweet Potato Peels on Hydraulic Retention Time, Methane Yield and Its Kinetics

This paper presents the results of batch anaerobic co-digestion of matooke, cassava, and sweet potato peels and vines. These agricultural wastes and others form the biggest portion of household wastes in developing countries. However, they have remained an unexploited resource amidst the ever increasing needs of clean energy and waste disposal challenges. Efforts to use them individually as biogas substrates have been associated with process acidification failure resulting from their fast hydrolysis. The aim of this work was to exploit agricultural wastes is co-digestion among themselves and assess their effect on methane yield and its kinetics, pH and hydraulic retention time (HRT). Sixteen ratios of Matooke peels (MP), cassava peels (CP) and sweet potato peels (SP) were assessed in duplicate. Methane yield and its kinetics, pH and HRT demonstrated dependence on the proportion of substrates in the mixture. Depending on the ratio mixture, HRT increased to 15 days compared to less than 5 days for single substrates, hydrolysis rate constant (k) reduced to a range of 0.1 - 0.3 d-1 compared to single substrates whose k-values were above 0.5 d-1, pH was maintained in the range of 6.38 - 6.43 and CH4 yield increased by 15% - 200%. Ratios 2:1:0, 2:0:1, 0:1:2, 1:1:1 and 1:1:4 were consistent all through in terms of model fitting, having a positive synergetic effect on HRT, hydrolysis rate constant, lag phase and methane yield. However, more research is needed in maintaining the pH near the neutral for process stability assurance if household wastes are to be used as standalone substrates for biogas production without being co-substrates with livestock manure.

Bioenergy Production from Anaerobic Co-Digestion of Sewage Sludge and Abattoir Wastes

Energy is the pillar of human economic development. Several energy sources, renewable and non-renewable, have been exploited to assure and sustain the need for sustainable development. However, depletion of non-renewable energy sources forced researchers to search for alternative cost effective and environmental friendly energy sources. Thus, conversion of waste materials into energy has obtained considerable attention. In line with this, the aim of this study is to investigate the improvement of bio-energy production through anaerobic digestion of mixture of wastes from sewage sludge and abattoir sources. The abattoir waste is functioned as a co-substrate. Laboratory scale batch anaerobic co-digestion of the waste is carried out under mesophilic condition for 20 days. Sewage Sludge (SS) alone, and different mix ratios of SS to Abattoir Waste (AW) were analyzed for bioenergy production. Besides, the nutrient values and reduction in volume of the sewage after digestion were determined. The results show that methane productions of 33.8%, 48.3% and 56.9% were obtained for SS alone and for SS:AW mix ratios of 4:1 and 3:2, respectively. The nutrient values of the slurry increased as mix ratio decreased due to the increase in the amount of AW. The obtained results indicate that bio-energy production can be improved through co-digestion of SS using AW as a co-substrate;thus warranting further investigation for the practical application in the energy production.

Comparative Study of Biogas Production from Jackfruit Waste, Banana Peels, and Pineapple Peels Co-Digested with Cow Dung

Only 42% of Uganda’s population has access to electricity. The population continues to use firewood and charcoal as a source of energy, which leads to depletion of forests thus to climate change. The purpose of this study was to assess the potential of biogas production from jackfruit waste, banana peels, and pineapple peels when co-digested with cow dung as an alternative energy source. Substrates for each waste were co-digested with varying proportions (0%, 25%, and 50%) of cow dung using laboratory-scale 250 mL anaerobic digestors. The total biogas generation for jackfruit waste, banana peels, and pineapple peels after 30 days of anaerobic digestion was 82.3, 189, and 262 mL, respectively. When jack fruit waste, pineapple peels and banana peels were co-digested with 25% cow dung, the total amount of biogas produced increased by a factor of two and three, respectively. However, 50% of cow dung only significantly (p ≤ 0.05) improved for jack fruit waste by two folds. Therefore, the results indicated that jackfruit waste, banana and pineapple peels can be used for biogas production to augment energy supply. .

Biohydrogen Production from Synthetic Waste Co-digested with Liquid Dairy Cow Manure： Effect of Temperature and Mixing Ratio

Biohydrogen production from synthetic waste, SW （model organic fraction of municipal solid waste） co-digested with liquid dairy manure （M） was tested in batch reactions to assess the effect of temperature and mixing ratio of the substrates. A 5 × 2 factorial design experiment was conducted. Synthetic waste： manure mixtures of 1：1, 2：1, 3：1, 1：0, 0：1 （volatile solids, VS, basis） were tested at 37 （T37） and 55 ℃ （T55） using thirty 1 L laboratory scale digesters. Total VS of each mixture was 50 g/L except SW：M 0：I treatment, where total VS was 27.4 g/L. Gas samples were taken daily to determine hydrogen production, and slurry samples taken before and after experimentation, were analyzed for volatile fatty acid （VFA） concentration, volatile solid （VS） degradation, ammonium nitrogen （NH4＋-N） and pH. Hydrogen production （mL/g-VS fed） showed a significant two-factor interaction between incubation temperature and SW：M ratio （P 〈 0.001）. Maximum production of 15.8 mL/g-VS （fed） was achieved in SW：M ratio of 3：1 at 55 ℃. Generally, hydrogen productions at thermophilic temperature （T55） were significantly higher than at mesophilic （T37） temperature for all treatments （P 〈 0.001） except for SW：M 1：0 and SW：M 0：1 treatments （P 〉 0.05）. This study indicates that hydrogen production from co-digestion of synthetic waste and manure is dependent on incubation temperature and relative contribution of wastes in the mixture.

Anaerobic co-digestion of thermo-alkaline pretreated microalgae and sewage sludge: Methane potential and microbial community

To improve methane production from sewage sludge(SS),co-digestion of SS and microalgae(MA)was studied and the application of thermo-alkaline pretreatment to MA was evaluated.The results showed that thermo-alkaline pretreatment at 90℃ for 120 min on MA was the optimum pretreatment condition.Furthermore,when the volatile solids(VS)ratio of SS and MA was 1:2,the methane yield reached maximum(368.94 mL/g VS).Fourier transform infrared(FT-IR)and thermogravimetric analysis confirmed the synergetic effects of thermoalkaline pretreated MA on its co-digestion with SS.The analyses of microbial community indicated that Methanobacterium and Methanosarcina were the dominant methanogens during the co-digestion process.However,the relative abundance of Methanosarcina in thermoalkaline pretreated groups was higher compared to unpretreated groups.The microbial community structure might be affected by thermo-alkaline pretreatment rather than by the MA dosage in the co-digestion.

Co-digestion of food waste and hydrothermal liquid digestate:Promotion effect of self-generated hydrochars

Hydrothermal treatment(HTT)can efficiently valorize the digestate after anaerobic digestion.However,the disposal of the HTT liquid is challenging.This paper proposes a method to recover energy through the anaerobic co-digestion of food waste and HTT liquid fraction.The effect of HTT liquid recirculation on anaerobic co-digestion performance was investigated.This study focused on the self-generated hydrochars that remained in the HTT supernatant after centrifugation.The effect of the self-generated hydrochars on the methane(CH_(4))yield and microbial communities were discussed.After adding HTT liquids treated at 140 and 180
C,the maximum CH4 production increased to 309.36 and 331.61 mL per g COD,respectively.The HTT liquid exhibited a pH buffering effect and kept a favorable pH for the anaerobic co-digestion.In addition,the self-generated hydrochars with higher carbon content and large oxygen-containing functional groups remained in HTT liquid.They increased the electron transferring rate of the anaerobic co-digestion.The increased relative abundance of Methanosarcina,Syntrophomonadaceae,and Synergistota was observed with adding HTT liquid.The results of the principal component analysis indicate that the electron transferring rate constant had positive correlationships with the relative abundance of Methanosarcina,Syntrophomonadaceae,and Synergistota.This study can provide a good reference for the disposal of the HTT liquid and a novel insight regarding the mechanism for the anaerobic co-digestion.

Investigates of substrate mingling ratio and organic loading rate of KOH pretreated corn stover and pig manure in batch and semi-continuous system:Anaerobic digestion performance and microbial characteristics

The effects of substrate mingling ratio(SMR)(1:1,1:2,1:3,3:1,and 2:1)and organic loading rate(OLR)(50-90 g total solids per liter per day)on anaerobic co-digestion performance and microbial characteristics were investigated for pig manure(PM)and pretreated/untreated corn stover in batch and semicontinuous anaerobic digestion(AD)system.The results showed that SMR and pretreatment affected co-digestion performance.The maximum cumulative methane yield of 428.5 ml·g^(-1)(based on volatile solids(VS))was obtained for PCP13,which was 35.7%and 40.0%higher than that of CSU and PM.In the first 5 days,the maximum methane yield improvement rate was 378.1%for PCP13.The daily methane yield per gram VS of PCP13 was 11.4%-18.5%higher than that of PC_(U)13.Clostridium_sensu_stricto_1,DMER64,and Bacteroides and Methanosaeta,Methanobacterium,and Methanospirillum had higher relative abundance at the genus level.Therefore,SMR and OLR are important factor affecting the AD process,and OLR can affect methane production through volatile fatty acids.

超高效液相色谱-电喷雾飞行时间质谱联用法检测癫痫平片中β-细辛醚含量

目的建立测定石菖蒲有效成分β-细辛醚含量的超高效液相色谱-电喷雾飞行时间质谱联用法(UPLC-TOF/MS)。方法应用Waters Acquity超高效液相色谱(UPLC)BEH C18柱(100 mm×2.1 mm,1.7μm),流动相为甲醇-水(65∶35),流速为0.4 mL/min,柱温为35℃;采用Waters LCT Premier XE(飞行时间质谱仪)电喷雾电离源正离子模式,取m/z 209.117 8作为定量目标离子进行检测。结果β-细辛醚进样量线性范围是74.2～927.5 pg,线性相关系数为0.999 0;平均加样回收率为96.2%,RSD为0.94%(n=6)。仪器最低检出限为14.84 pg。结论该方法简单、快速、准确、重复性好,适用于癫痫平片中石菖蒲有效成分β-细辛醚含量的检测。