Effects of Ferric Salts on Sludge Anaerobic Digestion and Desulphurization

2018 ◽  
Vol 913 ◽  
pp. 887-892
Author(s):  
Run Zhuan ◽  
Guang Yang ◽  
Guang Ming Zhang ◽  
Wei Wang
Keyword(s):  
Anaerobic Digestion ◽  
Ferric Chloride ◽  
Biogas Production ◽  
Removal Rate ◽  
Sulfur Removal ◽  
Gas Production ◽  
Control Group ◽  
Potassium Ferrate ◽  
Nitrogen And Phosphorus ◽  
Remarkable Effect

The treatment and disposal of excess sludge is a great challenge. Anaerobic digestion can achieve sludge reduction and harmless. However, its application is largely limited due to the low biogas production, low organic matters removal rate, odor gas production, corrosive gas destroying equipment. Sulfur is a key element resulting in these problems. In this research, potassium ferrate and ferric chloride were added to enhance anaerobic digestion. The research investigated the effects on biogas production, H2S content, microbial diversity with the addition of potassium ferrate and ferric chloride. We found that with 2.5 mg/g TS potassium ferrate, the enhancement was the highest, the total biogas production improved 18% compared with control group and organic removal rate reached 30.66%. Considering the effect of sulfur removal, 5 mg/g TS potassium ferrate resulted in the best effect, the content of H2S gas decreased 139.4%. With 2.5 mg/g TS ferric chloride, total biogas production improved 8% comparing with the control group, the content of H2S gas decreased 46%, no remarkable effect was found on the content of nitrogen and phosphorus in slurry.

scholarly journals Effect of yeast addition on the biogas production performance of a food waste anaerobic digestion system

2020 ◽  
Vol 7 (8) ◽  
pp. 200443
Author(s):  
Ming Gao ◽  
Shuang Zhang ◽  
Xinxin Ma ◽  
Weijie Guan ◽  
Na Song ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Food Waste ◽  
Biogas Production ◽  
Gas Production ◽  
Production Performance ◽  
Organic Load ◽  
Control Group ◽  
Volatile Solids ◽  
Volatile Organic ◽  
The Stability

Food waste contains numerous easily degradable components, and anaerobic digestion is prone to acidification and instability. This work aimed to investigate the effect of adding yeast on biogas production performance, when substrate is added after biogas production is reduced. The results showed that the daily biogas production increased 520 and 550 ml by adding 2.0% (volatile solids; VS) of activated yeast on the 12th and 37th day of anaerobic digestion, respectively, and the gas production was relatively stable. In the control group without yeast, the increase of gas production was significantly reduced. After the second addition of substrate and yeast, biogas production only increased 60 ml compared with that before the addition. After fermentation, the biogas production of yeast group also increased by 33.2% compared with the control group. Results of the analysis of indicators, such as volatile organic acids, alkalinity and propionic acid, showed that the stability of the anaerobic digestion system of the yeast group was higher. Thus, the yeast group is highly likely to recover normal gas production when the biogas production is reduced, and substrate is added. The results provide a reference for experiments on the industrialization of continuous anaerobic digestion to take tolerable measures when the organic load of the feed fluctuates dramatically.

Effect of Oil Content on Dry Anaerobic Digestion of Food Waste under Mesophilic Conditions

2015 ◽  
Vol 768 ◽  
pp. 281-288
Author(s):  
Lian Hai Ren ◽  
Yan Bing Huang ◽  
Pan Wang
Keyword(s):  
Anaerobic Digestion ◽  
Food Waste ◽  
Oil Content ◽  
Continuous Fermentation ◽  
Biogas Production ◽  
Removal Rate ◽  
Gas Production ◽  
Composition Analysis ◽  
Volatile Solids ◽  
Dry Anaerobic Digestion

The variations of daily biogas yields, cumulative biogas yields, biogas composition analysis, total solids (TS) and volatile solids (VS) were studied in the process of mesophilic and dry anaerobic digestion of food waste under different oil contents (0%, 2%, 4%, 6%, 8%, 10%) at 35 °C. The gas production raised and then went down with the oil content, followed by 243.14, 245.64, 256.09, 269.25, 276.54, 284.22mL /g TS respectively. The research provided a reference for the pretreatment of food waste in follow-up continuous fermentation. Results showed that the period of the process of mesophilic dry anaerobic digestion under oil content of 0% was the shortest, with the total biogas production of 1275.5mL. During the process of the digestion, methane content of the biogas raised and then went down, up to a maximum of 77.62%. The removal rate of TS and VS in food waste with the oil content of 6% was the highest, obtained as 11.2% and 13.2%, respectively.

Enhancement of Sewage Sludge Anaerobic Digestibility by Sulfate Radical Pretreatment

2012 ◽  
Vol 518-523 ◽  
pp. 3358-3362 ◽  
Author(s):  
De Dong Sun ◽  
Hua Mei Liang ◽  
Chun Ma
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Removal Rate ◽  
Gas Production ◽  
Sulfate Radical ◽  
Methane Yield ◽  
Control Group ◽  
Pretreatment Condition ◽  
The Stability ◽  
Anaerobic Digestibility

The effect of sulfate radical(SO4−•) pretreatment on mesophilic anaerobic digestion of sewage sludge was investigated and compared with a control group. The results showed that pretreatment can effectively improve sludge anaerobic digestion performance. After sulfate radical pretreatment, the removal rate of TCOD during the digestion was increased by 11.5% , the cumulative gas production was increased by 44.9%.The VFA concentration increased in the supernatant after pretreatment, but the alkalinity was also increased at the same time, so as to ensure the stability of whole system. The highest methane yield under pretreatment condition was 0.27m3 CH4/kgVSremoval, 180.0% of the control. The results indicated that persulfate /K2S2O8 pretreatment could be an effective method for improving methane yield.

Experimental Studies on Enhanced Coagulation of Tail Water

2013 ◽  
Vol 295-298 ◽  
pp. 1478-1481
Author(s):  
Feng Xun Tan ◽  
Jiu Mei Wang ◽  
Dao Ji Wu
Keyword(s):  
Ferric Chloride ◽  
Removal Rate ◽  
Reclaimed Water ◽  
Experimental Studies ◽  
Ammonia Nitrogen ◽  
Raw Water ◽  
Nitrogen And Phosphorus ◽  
Enhanced Coagulation ◽  
Tail Water ◽  
Water Eutrophication

Traditional wastewater treatment methods can no longer remove effectively nitrogen and phosphorus that are the direct murderers of water eutrophication hazard. Enhanced coagulation method was adopted to improve the treatment effect by dosing suitable coagulants and coagulant aids. The raw water was from the reclaimed water in a University. TP and ammonia nitrogen removal of the water had been researched through an enhanced coagulation process with dosing ferric chloride, aluminum sulfate, polymeric ferric chloride, and poly-aluminum chloride (PAC) in this study. The coagulants effects were estimated by determining the removal rate of ammonia nitrogen, TP, COD and turbidity. When dosing the raw water with 80 mg/L PAC, the removal rates of ammonia nitrogen, TP, COD and turbidity are respectively 6.12%, 67.79%, 26.21%, 85.41%. The experimental results can be used as a reference of water treatment in the reclaimed water station.

Study of Methane Production by High Temperature Anaerobic Fermentation of Chicken Manure and Stalks

2020 ◽  
Vol 14 (4) ◽  
pp. 551-557
Author(s):  
Yongku Li ◽  
Xiaomin Hu ◽  
Lei Feng
Keyword(s):  
High Temperature ◽  
Anaerobic Digestion ◽  
Production Rate ◽  
Methane Production ◽  
Anaerobic Fermentation ◽  
Biogas Production ◽  
Gas Production ◽  
Chicken Manure ◽  
Biogas Slurry ◽  
Production Rates

The changing parameters, as the biogas production rate, the methane production rate, the cumulative biogas amount, the cumulative methane amount, the biogas composition, pH etc. in high temperature anaerobic fermentation of chicken manure and stalks were analyzed by experiments with different mass ratios of chicken manure or livestock manure and stalks with a high C/N ratio. The methane production mechanism of high temperature anaerobic digestion of chicken manure and stalks was discussed in detail. It showed that not only the biogas production rates but also the methane production rates of R1–R7 demonstrated the trend of initial increase and then decrease after 50 d of high temperature anaerobic digestion. Besides, the gas production of R1 with pure chicken manure stopped on the 30th d of the reaction. The gas production of other groups R2–R7 also stopped on the corresponding 34th, 36th, 36th, 37th, 37th, and 37th day, respectively. At the end of the reaction, the cumulative biogas amounts and the cumulative methane amounts of R1–R7 were 411.58 and 269.54, 459.91 and 314.41, 425.32 and 294.11, 401.85 and 272.54, 382.63 and 257.07, 363.04 and 218.16, and 257.15 and 160.10 N ml/(g VS). The biogas slurry pH of R1–R7 all demonstrated a trend of initial decrease and then increase, e. g., pH of R2 reached the minimum of 5.94 on the 5th day. pH values of other groups were between 6.01 and 6.39. After the addition of 4 g of sodium bicarbonate on the 7th day, biogas slurry pH of R1–R7 all increased. pH was maintained between 7.16 and 7.44 until the end of the reaction.

Mesophilic Anaerobic Digestion of Dairy Manure and Vegetable Waste Using Batch Reactor

2014 ◽  
Vol 1008-1009 ◽  
pp. 121-126
Author(s):  
Lin Jun Shi ◽  
Wen Lan Liu ◽  
Hui Fen Liu ◽  
Wei Yu Zhang ◽  
Li Tong Ban
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Batch Reactor ◽  
Theoretical Data ◽  
Gas Production ◽  
Dairy Manure ◽  
Experimental Results ◽  
Vegetable Waste ◽  
Start Up ◽  
Waste Mixture

Anaerobic digestion of single dairy manure, single vegetable waste, mixture of dairy manure and vegetable waste was conducted to produce biogas. Startup characteristic, leachate parameters and inoculation amount were investigated. The experimental results showed that anaerobic digestion can start up quickly with acclimated thickening sludge as inoculation sludge and 30% was appropriate inoculation percentage. Digestion of single dairy manure and mixture of dairy manure and vegetable waste appeared better buffering ability with higher alkalinity than single vegetable waste. Compared to single digestion of dairy manure or vegetable waste, mixture of dairy manure and vegetable waste is more suitable for anaerobic digestion. Under the conditions of TS=10% and T=(36±1)°C, cumulative biogas production of mixture of dairy manure and vegetable waste is 5281 mL during the period of 30 days and average daily gas production is about 176 mL. These results could provide theoretical data for practical biogas engineering.

scholarly journals Evaluation of acidogenic sludge from anaerobic reactors running at low solids retention times to reduce sludge generation and enhance biogas production

Water SA ◽  
2019 ◽  
Vol 45 (4 October) ◽  
Author(s):  
Wilza Da Silva Lopes ◽  
Ysa Helena Diniz Morais de Luna ◽  
Jose Tavares de Sousa ◽  
Wilton Silva Lopes ◽  
Valderi Duarte Leite
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Kinetic Constant ◽  
Oxygen Demand ◽  
Gas Production ◽  
Primary Sludge ◽  
Anaerobic Reactors ◽  
Solids Retention ◽  
Improved Performance ◽  
Pre Treatment

ABSTRACT   Sludges generated in the biological processing of sewage are complex mixtures, the constituents of which pose risks to public health and the environment. Anaerobic digestion is considered the most sustainable option for treating sludge because it offers the possibility of generating biogas. The aim of this study was to compare the quantities, properties, biodegradabilities and biochemical methane potentials (BMP) of primary sludge (PS) generated by a primary decanter with acidogenic sludges produced by upflow anaerobic (UA) reactors operating at solids retention times (SRTs) of 2, 4, 6 and 8 days (Samples S2, S4, S6 and S8, respectively). Sludges from both pre-treatments were submitted to alkaline solubilization in order to determine the efficiency of the process in disrupting extracellular complexes. Based on the levels of total solids (TS) present, the primary decanter was found to generate higher quantities of excess sludge (yield of 3.1 gTS∙d-1) than UA reactors operating at low SRTs (yields in the range 1.69 to 0.64 gTS∙d-1). The concentrations of dissolved materials in PS and Samples S2 and S8 were considerably higher after alkaline solubilization, with respective increases of 8, 14 and 28-fold in dissolved organic carbon, 12, 20 and 40-fold in chemical oxygen demand, 25, 31 and 59-fold in proteins, and 17, 21 and 63-fold in carbohydrates. In addition, the BMP value for S8 was some 13% higher than that recorded for PS while the kinetic constant for gas production by S8 was 1.8-fold greater than that of PS. It is concluded that a pre-treatment combining anaerobic digestion at low SRT and alkaline solubilisation would lead to improved performance in subsequent stages of anaerobic digestion and, consequently, increased efficiency in biogas production.

scholarly journals Kinetic Study on Biogas Production from Cabbage (Brassica oleracea) Waste and Its Blend with Animal Manure Using Logistic Function Model

2021 ◽  
pp. 34-43
Author(s):  
Christian C. Opurum
Keyword(s):  
Anaerobic Digestion ◽  
Kinetic Parameters ◽  
Goodness Of Fit ◽  
Biogas Production ◽  
Logistic Function ◽  
Gas Production ◽  
Cow Dung ◽  
Function Model ◽  
Biogas Yield ◽  
Significant Difference

This research paper aimed to evaluate the kinetics of anaerobic digestion (AD) of mixtures of cabbage waste (CW) with (Poultry dropping (PD) and Cow dung (CD). The study was conducted in 10L bio-digesters for 35 days under mesophilic conditions (25 - 35OC). Logistic function equation was used to simulate the experimental data to test for its goodness of fit and kinetic parameters namely: maximum biogas potential (Pb), the maximum biogas production rate (Rm), and the lag phase duration (λ) were estimated in each treatment. Chemical analysis showed that individual substrates possess characteristics that could support microbial activities in biogas production. The biogas yield in terms of added  volatile solids (VS) in decreasing order was as follows: 0.022, 0.018, 0.017, 0.014, 0.014 and 0.013 dm3/g VS for CW/CD 2:1, CW/PD3:1, CW/CD 1:1, CW alone, CW/PD1:1 and  CW/PD 2:1, respectively. A significant difference (P ≤ 0.05) in biogas yield was recorded in CW/CD 2:1 with 7.19 dm3 (53.29% increase). The kinetic parameters (Pb, Rm, and λ) for CW/CD 2:1 was 7.01 dm3, 1.58 dm3.d, and 2.29 days, respectively. This was followed by CW/PD 3:1 (5.84 dm3); with 24.92% increase in gas production and CW/CD 1:1 (5.42 dm3) with 15.53% increase relative to CW alone, 4.69 dm3. The digesters fed with CW/PD 1:1 and CW/PD 2:1 exhibited inhibitory effects on biogas production, with 7.51 and 2.05% decrease in gas yield, respectively. The logistic function model demonstrated a strong relationship between the experimental and model-predicted data. The high correlation coefficient (R2) ranging between 0.978 - 0.993 is evident. The model proved to be a useful tool in predicting anaerobic digestion and biogas production process.

scholarly journals Aeration to Improve Biogas Production by Recalcitrant Feedstock

Environments ◽  
2019 ◽  
Vol 6 (4) ◽  
pp. 44 ◽  
Author(s):  
John Loughrin ◽  
Nanh Lovanh
Keyword(s):  
Carbon Dioxide ◽  
Anaerobic Digestion ◽  
Methane Production ◽  
Biogas Production ◽  
Day Treatment ◽  
Poultry Litter ◽  
Gas Production ◽  
Quality Degradation ◽  
Small Scales ◽  
Low Levels

Digestion of wastes to produce biogas is complicated by poor degradation of feedstocks. Research has shown that waste digestion can be enhanced by the addition of low levels of aeration without harming the microbes responsible for methane production. This research has been done at small scales and without provision to retain the aeration in the digestate. In this paper, low levels of aeration were provided to poultry litter slurry through a sub-surface manifold that retained air in the sludge. Digestate (133 L) was supplied 0, 200, 800, or 2000 mL/day air in 200 mL increments throughout the day via a manifold with a volume of 380 mL. Digesters were fed 400 g of poultry litter once weekly until day 84 and then 600 g thereafter. Aeration at 200 and 800 mL/day increased biogas production by 14 and 73% compared to anaerobic digestion while aeration at 2000 mL/day decreased biogas production by 19%. Biogas quality was similar in all digesters albeit carbon dioxide and methane were lowest in the 2000 mL/day treatment. Increasing feed to 600 g/week decreased gas production without affecting biogas quality. Degradation of wood disks placed within the digesters was enhanced by aeration.

The contribution of thermophilic anaerobic digestion to the stable operation of wastewater sludge treatment

2002 ◽  
Vol 46 (4-5) ◽  
pp. 447-453 ◽  
Author(s):  
J. Zábranská ◽  
M. Dohányos ◽  
P. Jeníček ◽  
P. Zaplatílková ◽  
J. Kutil
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Removal Rate ◽  
Wastewater Sludge ◽  
Anaerobic Sludge ◽  
Stable Operation ◽  
Sludge Treatment ◽  
Thermophilic Anaerobic Digestion ◽  
Mesophilic Digestion ◽  
Pathogens Removal

Thermophilic anaerobic digestion of sewage sludge has been successfully operated in full-scale tanks almost three years. The higher loading capacity and specific biogas production rate in comparison with mesophilic digestion was proved. Thermophilic anaerobic sludge is also more resistant against foaming problems. Biogas from thermophilic tanks contains less hydrogen sulphide and other malodorous substances. Pathogens removal rate is apparently more efficient in the thermophilic process.

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