Papers by Keyword: Anaerobic Fermentation

Abstract: Concerning the treatment of tannery wastewater with high COD (chemical oxygen demand), the effective process is physical-chemical and anaerobic treatment. The core technology of anaerobic treatment is to test the performance of anaerobic degradation of organic matter, clarify the inhibitory effect and inhibitory mechanism of pollutant. In this paper, anaerobic degradation and inhibitory effect of bayberry tannin extract were studied. In the course of the experiment, the production of methane, the activity of sludge and the content of coenzyme F420 were been tested, the bayberry tannin extract and degradation products were been tested by Fourier transform infrared spectroscopy (FT-IR). The results indicated that the 50% inhibitory concentration of bayberry tannin extract is about 3.3 g/L, the anaerobic fermentation has been inhibited is owing to bayberry tannin extract has the inhibition on methanogenic activity of methanogens, the production of methane, the activity of sludge and the content of coenzyme F420 are getting lower and lower with the increase in content of bayberry tannin extract. The characterization of FTIR showed that the bayberry tannin extract has been degraded in anaerobic fermentation. These all indicated that bayberry tannin extract can inhibit the anaerobic fermentation, and the greater amount, resulting in stronger inhibition, in appropriate concentrations, bayberry tannin extract can be degraded by anaerobic fermentation. The results can provide guidance for anaerobic treatment of tannery wastewater with high COD.

Abstract: In present times, replacing fossil fuels with renewable ones becomes a problem more and more stringent in the existing society. Related with this topic, biogas production, as one of the potential renewable fuels has an increasing role both at regional and global level in relation to the potential it poses for energetic independence, both for developed and in course of development countries. The present article intends to underline the potential usage of agricultural biomass (namely wheat bran and cereal mix) as renewable source of energy for biogas production. Factorial design of experiments was employed to study the effect of two factors (net calorific value and C/N ratio) on total biogas produced after 65 days of anaerobic digestion. Main effects and interaction effects of these factors were analyzed using statistical techniques. A regression model was obtained to predict the total biogas production and it was found to adequately fit the experimental range studied.

Abstract: With kitchen residues and cattle manure as raw materials, in temperature (36±1°C) adopt the way of the batch type fermented for kitchen residues and cattle manure, we will have a comparative research between independent anaerobic fermentation and mixed anaerobic fermentation. The results of the experiments show that the gas production and COD removal rate by the anaerobic fermentation of cattle manure independent would be superior to kitchen residues, the optimal effect is the anaerobic fermentation of kitchen residues mixed with cattle manure in all aspects .In this experiment all the kitchen residues are rice, vegetables, meat, eggs and other food all that have been after cooked, containing a large number of fat and salt, such condition is not suitable for the growth of microorganism. The time of gas production is only nine days and gas production rate is extremely low, only 1500ml accumulative gas production, But cattle manure’s accumulative gas production is 3028ml, COD removal rate was 21%, COD removal rate by mixed anaerobic fermentation of kitchen residues and cattle manure can achieve 60.92%.

Abstract: In order to study the influence of temperature and total solid on biogas components of thermostatic anaerobic fermentation of cattle dung, three parallel anaerobic digesters of 11.5L of three group were operated in batch mode at temperature of 30°C,37°C and 52°C respectively and real-time analysises were carried out to determine the biogas composition with Biogas Check. When the temperature was the same, total solid (TS) which was 8% was the good choice for anaerobic fermentation, while the TS was same,37°C was the choose to get the maximum yield of the methane production, the cumulative methane production was 12.56L/TS,and the average methane content of the percentage by volume was 53.59%.This study could provide useful parameters for the anaerobic fermentation of cow dung.

Abstract: Biogenic gas is an important end-product of methanogenesis in an anoxic environment. Based on the coal, coal-gangue, mine water of Songzao Coal Mine and in the case of adding inoculums, the quantities of gas and the contents of methane are measured by the microorganism action, and also respectively measured fermentation broth and residues by NO3--N, NH4+-N, S2- , SO42-, the values of pH, metals and the organic matter. The results show that coal and coal-gangue are involved in the microbial role; the quantity of inoculums is directly related to the quantities of gas and the contents of methane, at the same time it has a certain degree of impact on the contents of NO3--N, NH4+ -N, S2- , SO42- and metals; besides, because of the microbial anaerobic fermentation, the contents of NH3+ are seriously substandard; overall, the group B which has a smaller proportion of coal-gangue has a less impact to the environment compared to the group A which has a larger proportion of coal-gangue. In the further research into the direction of organic matter and obtaining and using the biogas, we must prevent secondary pollution of groundwater at the same time.

Abstract: Anaerobic fermentative technology is an important route to solving environmental pollution and resources problems. Combined hydrogen and methane production in a two-stage process is a concept which has been developed in recent years Anaerobic biological treatment organic wastewater can produce large amounts of hydrogen and methane，which can be used as energy carrier. At present，the research focusing on the adjustment of fermentation hydrogen-methane production has been conducted. Furthermore, the simultaneous hydrogen-methane production was tested and optimized. However, it lacked combined hydrogen-methane production in an anaerobic reactor in literature so far. Based on preview experiment, the paper studied the simultaneous hydrogen-methane fermentation in an anaerobic baffled reactor (ABR) system. ABR has the advantage of biomass phase separation and integration of acidogenic and methanogenic processes to simultaneously conduct hydrogen-methane production during wastewater treatment. Through deep biohydrogen production, it can enhance the activity of hydrogen-producing acetogens (HPA) and the efficiencies of the combined hydrogen-methane fermentation system. It showed to enhance the activity of HPA was the key to the combined hydrogen-methane production.

Abstract: Two continuously stirred tank reactors (CSTR) were used to investigate the effect of L-cysteine on continuous dark fermentative hydrogen production system. L-cysteine was added into one of the reactors at 0.1 g/L continuously, the other reactor was without L-cysteine addition. Liquid end products, oxidation-reduction potential (ORP), pH, biomass and hydrogen production rate (HPR) were examined during the operation. The lag time of ethanol generation in the L-cysteine added reactor was shortened to 21 days compared to 25 days in the blank. The HPR increased from 2.73 L/d in the reactor without L-cysteine addition to 2.82 L/d in the added one. The volatile suspended solids (VSS) in the reactor with L-cyateine was 10.1 g/L by the end of the operation compared to 9.2 g/L in the other. Addition of L-cysteine into the hydrogen production system accelerates the formation of ethanol-type fermentation and enhances the hydrogen production by creating an optimal low ORP environment, and by increasing the biomass growth simultaneously.

Abstract: The experiment took a continuous stirred tank reactor as a reacting device, which based on molasses wastewater and brown sugar wastewater as the fermentation substrate. We studied the hydrogen production capacity with the two different substrates under the anaerobic fermentation. The results showed that the maximum hydrogen production yield were 0.99 L/d (molasses as the substrate) and 1.95L/d (brown sugar as the substrate), respectively, with the hydraulic retention time (HRT) of 6.2 h, temperature of (35 ± 1) °C and the reactor substrate concentration of 3000 mg COD/L. At the same time, the liquid end components were changed in a large scope. During the first 28 days, acetic acid and propionic acid were the main components, when molasses was replaced by brown sugar as the substrate, the percentages of propionic acid and butyrate acid decreased significantly from 25.7%, 15.4% to 11.8%, 9.47%, respectively. And the fermentation type was transformed from the mixed-acid-type fermentation to the more stable ethanol-type fermentation.

Abstract: A constant temperature fermentation system was self-designed and used to study the relationships of gas production efficiency with time and temperature of digestion in anaerobic fermentation of Pineapple Leaf residue. Groups of experiments were conducted with total solids concentration (TS) being 20% and fermentation temperatures of four groups respectively being 25°C, 30°C, 35°C, and 40°C. Experiment results showed that the total gas yield of the group with 35°C was 662.8 L, which was much higher than gas yields of the other groups. The methane content of the group was 63.2%, almost the same with other groups. Multiple regression analysis was made with SAS software and the regression equation was set up. The optimum temperature, digestion time and maximum cumulative gas production of solids were 36.4°C, 55d, and 462.41mL/g respectively.

Abstract: This paper reported an experiment about anaerobic fermentation of cow dung and slurry from hydrogen fermentation production of sucrose by using anaerobic batch fermentation at temperature of 30°C, the results indicated that methane fermentation production can be achieved through this experiment with 40d anaerobic fermentation, its biogas yield is 212 ml/g TS and 239ml/g VS, fresh material biogas yield is 46 ml/g.