Co-digestion of agricultural and municipal waste to produce energy and soil amendment

In agriculture, manure and cotton gin waste are major environmental liabilities. Likewise, grass is an important organic component of municipal waste. These wastes were combined and used as substrates in a two-phase, pilot-scale anaerobic digester to evaluate the potential for biogas (methane) production, waste minimisation, and the digestate value as soil amendment. The anaerobic digestion process did not show signs of inhibition. Biogas production increased during the first 2 weeks of operation, when chemical oxygen demand and volatile fatty acid concentrations and the organic loading rate to the system were high. Chemical oxygen demand from the anaerobic columns remained relatively steady after the first week of operation, even at high organic loading rates. The experiment lasted about 1 month and produced 96.5 m3 of biogas (68 m3 of CH4) per tonne of waste. In terms of chemical oxygen demand to methane conversion efficiency, the system generated 62% of the theoretical methane production; the chemical oxygen demand/volatile solids degradation rate was 62%, compared with the theoretical 66%. The results showed that co-digestion and subsequent digestate composting resulted in about 60% and 75% mass and volume reductions, respectively. Digestate analysis showed that it can be used as a high nutrient content soil amendment. The digestate met Class A faecal coliform standards (highest quality) established in the United States for biosolids. Digestion and subsequent composting concentrated the digestate nitrogen, phosphorus, and potassium content by 37%, 24%, and 317%, respectively. Multi-substrate co-digestion is a practical alternative for agricultural waste management, minimisation of landfill disposal, and it also results in the production of valuable products.

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Anaerobic baffled reactor treatment of biodiesel-processing wastewater with high strength of methanol and glycerol: reactor performance and biogas production

Chemical Papers ◽

10.2478/s11696-011-0061-y ◽

2011 ◽

Vol 65 (5) ◽

Cited By ~ 10

Author(s):

Darin Phukingngam ◽

Orathai Chavalparit ◽

Dararat Somchai ◽

Maneerat Ongwandee

Keyword(s):

Chemical Oxygen Demand ◽

Volatile Fatty Acids ◽

Biogas Production ◽

Oxygen Demand ◽

Anaerobic Treatment ◽

Organic Loading Rate ◽

Organic Loading ◽

Reactor Performance ◽

Electron Microscopic ◽

Anaerobic Baffled Reactor

AbstractBiodiesel-processing factories employing the alkali-catalyzed transesterification process generate a large amount of wastewater containing high amount of methanol, glycerol, and oil. As such, wastewater has high potential to produce biogas using anaerobic treatment. The aim of this research was to investigate the performance of an anaerobic baffled reactor for organic removal and biogas production from biodiesel wastewater. The effect of different organic loading rates, varying from 0.5 kg m−3 d−1 to 3.0 kg m−3 d−1 of chemical oxygen demand, was determined using three 22 L reactors, each comprising five separate compartments. Wastewater was pretreated with chemical coagulants to partially remove oil prior to experimentation. Results show that the anaerobic baffled reactor operated at 1.5 kg m−3 d−1 of chemical oxygen demand and ten days of hydraulic retention time provided the best removal efficiencies of 99 % of chemical oxygen demand, 100 % of methanol, and 100 % of glycerol. Increasing the organic loading rate over 1.5 kg m−3 d−1 of chemical oxygen demand led to excessive accumulation of volatile fatty acids thereby making the pH drop to a value unfavorable for methanogenesis. The biogas production rate was 12 L d−1 and the methane composition accounted for 64–74 %. Phase-separated characteristics revealed that the highest chemical oxygen demand removal percentage was achieved in the first compartment and the removal efficiency gradually decreased longitudinally. A scanning electron microscopic study indicated that the most predominant group of microorganisms residing on the external surface of the granular sludge was Methanosarcina.

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Evaluation of Organic Loading Rate and Chemical Oxygen Demand Removal: A Coupled Anaerobic-aerobic Treatment Approach for Molasses Distillery Stillage Treatment

10.21203/rs.3.rs-107266/v1 ◽

2020 ◽

Author(s):

Getachew D. Gebreeyessus ◽

Andualem Mekonnen ◽

Yonas Chebude ◽

Asaithambi Perumal ◽

Esayas Alemayehu

Keyword(s):

Chemical Oxygen Demand ◽

Sustainable Management ◽

Loading Rate ◽

Treatment Approach ◽

Oxygen Demand ◽

Complete Removal ◽

Organic Loading Rate ◽

Aerobic Treatment ◽

Organic Loading ◽

Promising Technique

Abstract The objective of the current study is to determine the optimum organic loading rate for a continuous anaerobic digestion (AD) of an ethanol distillery stillage with and without of feed pretreatment. The AD has been performed in scoria packed continuous reactors. The pretreatment of the molasses ethanol distillery stillage brought a significantly better chemical oxygen demand (COD) removal with an increased loading rate to 2000 mg/L-d, when compared with the raw. The results obtained also showed a complete removal of the BOD, which was realized after applying the coupling of AD and aerobic treatments. During aerobic treatment, 68% of the organics were removed within eight hours of retention time. Despite the persistence of color, the removal of organics from integrating the wet air pretreatment, continuous AD and aerobic remediations appear to be promising technique towards the sustainable management of stillage thereby meeting discharge limits.

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Influence of organic loading rates on the production of methane from anaerobic digestion of sewage concentrate

Energy & Environment ◽

10.1177/0958305x18769860 ◽

2018 ◽

Vol 29 (7) ◽

pp. 1130-1141 ◽

Cited By ~ 2

Author(s):

Emmanuel Alepu Odey ◽

Kaijun Wang ◽

Zifu Li ◽

Ruiling Gao

Keyword(s):

Methane Production ◽

Loading Rate ◽

Biogas Production ◽

Stirred Tank ◽

Organic Loading Rate ◽

Continuous Stirred Tank Reactor ◽

Organic Loading ◽

Stirred Tank Reactor ◽

Tank Reactor ◽

Continuous Stirred Tank

This study investigated the efficiency of biogas production from sewage concentrate through anaerobic digestion. A continuous stirred tank reactor with a 900-mL working volume was used. The experiment was designed to investigate the influence of organic loading rate on the efficiency of biogas production and to determine the most suitable organic loading rate condition for methane production from sewage concentrate by using continuous stirred tank reactor. The reactor was operated at different organic loading rates of 1.8, 0.8, and 0.6 gCOD/(L.d). The methane composition of the biogas produced from the treatment organic loading rate (OLR). The beginning of the experiment recorded low methane production because of the high organic loading rate. However, the later part of the experiment recorded high and stable biogas production because of the relatively low OLR. Results suggested that a 0.6 gCOD/(L.d) OLR was the most efficient setup parameter for ideal methane production from sewage concentrate by using continuous stirred tank reactor.

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Enhanced removal of chemical oxygen demand, nitrogen and phosphorus using the ameliorative anoxic/anaerobic/oxic process and micro-electrolysis

Water Science & Technology ◽

10.2166/wst.2012.258 ◽

2012 ◽

Vol 66 (4) ◽

pp. 850-857 ◽

Cited By ~ 3

Author(s):

K. Q. Bao ◽

J. Q. Gao ◽

Z. B. Wang ◽

R. Q. Zhang ◽

Z. Y. Zhang ◽

...

Keyword(s):

Chemical Oxygen Demand ◽

Hydraulic Retention Time ◽

Loading Rate ◽

Oxygen Demand ◽

Synthetic Wastewater ◽

Organic Loading Rate ◽

Organic Loading ◽

Nitrogen And Phosphorus ◽

Operational Conditions ◽

Removal Efficiencies

Synthetic wastewater was treated using a novel system integrating the reversed anoxic/anaerobic/oxic (RAAO) process, a micro-electrolysis (ME) bed and complex biological media. The system showed superior chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) removal rates. Performance of the system was optimised by considering the influences of three major controlling factors, namely, hydraulic retention time (HRT), organic loading rate (OLR) and mixed liquor recirculation (MLR). TP removal efficiencies were 69, 87, 87 and 83% under the HRTs of 4, 8, 12 and 16 h. In contrast, HRT had negligible effects on the COD and TN removal efficiencies. COD, TN and TP removal efficiencies from synthetic wastewater were 95, 63 and 87%, respectively, at an OLR of 1.9 g/(L·d). The concentrations of COD, TN and TP in the effluent were less than 50, 15 and 1 mg/L, respectively, at the controlled MLR range of 75–100%. In this system, organics, TN and TP were primarily removed from anoxic tank regardless of the operational conditions.

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Effect of Organic Loading Rate (OLR) of Slurry on Biogas Production Quality

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1115.325 ◽

2015 ◽

Vol 1115 ◽

pp. 325-330

Author(s):

Maizirwan Mel ◽

Nadiah Mohd Suhuli ◽

Avicenna ◽

Sany Izan Ihsan ◽

Ahmad Faris Ismail ◽

...

Keyword(s):

Loading Rate ◽

Biogas Production ◽

Oxygen Demand ◽

Continuous System ◽

Total Solid ◽

Organic Loading Rate ◽

Cow Dung ◽

Feeding Rates ◽

Organic Loading ◽

Biogas Yield

In this study, three different concentration of organic loading rate (OLR) were investigated to examine the effect of the change in the organic loading rate on the efficiency of the biogas production. Daily amount of biogas of different type of organic loading rate (OLR), rates of production of biogas, removal efficiencies of chemical oxygen demand (COD), total solid (TS) matter, volatile solids (VS) matter from the slurry were investigated in 30 days retention tyme using 50 L digester. The digester was operated at different organic feeding rates of 25000 mg/L COD, 50000 mg/L COD, and 75000 mg/L COD. The material used in this system is the fruits waste, vegetables waste and cow dung. The system operated in continuous system. The reactor showed stable performance with the highest quality of methane (concentration about70.3% of CH4) and rate of biogas production is 38.1 L/day with COD reduction of 52.1% during organic loading rate 50000 mg/L COD. As the organic loading rate was increased, the COD degradation and biogas yield decreased. Based on this result, the OLR of 50000 mg/L COD is suggested as design criteria for pilot biogas production.

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Performance and Operational Characteristics of Modified Anaerobic Hybrid Baffled (MAHB) Reactor Treating Low Strength Recycled Paper Mill Effluent (RPME) Wastewater

Scientific Research Journal ◽

10.24191/srj.v11i2.5422 ◽

2014 ◽

Vol 11 (2) ◽

pp. 33

Author(s):

Siti Roshayu Hassan ◽

Nastaein Qamaruz Zaman ◽

Irvan Dahlan

Keyword(s):

Biogas Production ◽

Oxygen Demand ◽

Paper Mill ◽

Gas Production ◽

Organic Loading Rate ◽

Organic Loading ◽

Recycled Paper ◽

Paper Mill Effluent ◽

Operational Characteristics ◽

Low Strength

The performance and operational characteristics of a laboratory scale modified anaerobic hybrid baffled (MAHB) reactor were studied using recycled paper mill effluent (RPME) wastewater. MAHB reactor was continuously operated at 35°C for 90 days with organic loading rate (OLR) increased from 0.14 to 0.57 g/L/dy. This present study demonstrated that the system was proficient in treating low strength RPME wastewater. Highest carbon oxygen demand (COD) removal were recorded up to 97% for an organic loading of 0.57 g /L/dy while effluent alkalinity assured that the system pH in the MAHB compartments were of great advantages to acidogens and methanogens respectively. Methane and biogas production rate shows increment as the load increases, which evidently indicated that the most significant approach to enhance gas production rates involves the increment of incoming substrate moderately. Variations of biogas and volatile fatty acid (VFA) in different compartments of MAHB reactor indicated the chronological degradation of substrate. The compartmental structure of MAHB reactor provided its strong ability to resist shock loads. From this present study, it shows the potential usage of MAHB reactor broadens the usage of multi-phase anaerobic technology for industrial wastewater treatment.

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Co-production of hydrogen and methane from herbal medicine wastewater by a combined UASB system with immobilized sludge (H2 production) and UASB system with suspended sludge (CH4 production)

Water Science & Technology ◽

10.2166/wst.2015.471 ◽

2015 ◽

Vol 73 (1) ◽

pp. 130-136 ◽

Cited By ~ 5

Author(s):

Caiyu Sun ◽

Ping Hao ◽

Bida Qin ◽

Bing Wang ◽

Xueying Di ◽

...

Keyword(s):

Herbal Medicine ◽

Hydrogen Production ◽

Production Rate ◽

Methane Production ◽

Oxygen Demand ◽

H2 Production ◽

Organic Loading Rate ◽

Anaerobic Sludge ◽

Organic Loading ◽

Production Of Hydrogen

An upflow anaerobic sludge bed (UASB) system with sludge immobilized on granular activated carbon was developed for fermentative hydrogen production continuously from herbal medicine wastewater at various organic loading rates (8–40 g chemical oxygen demand (COD) L−1 d−1). The maximum hydrogen production rate reached 10.0 (±0.17) mmol L−1 hr−1 at organic loading rate of 24 g COD L−1 d−1, which was 19.9% higher than that of suspended sludge system. The effluents of hydrogen fermentation were used for continuous methane production in the subsequent UASB system. At hydraulic retention time of 15 h, the maximum methane production rate of 5.49 (±0.03) mmol L−1 hr−1 was obtained. The total energy recovery rate by co-production of hydrogen and methane was evaluated to be 7.26 kJ L−1 hr−1.

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

Frontiers in Energy Research ◽

10.3389/fenrg.2021.740314 ◽

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.

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Alkali pre-treatment of Sorghum Moench for biogas production

Chemical Papers ◽

10.2478/s11696-012-0298-0 ◽

2013 ◽

Vol 67 (9) ◽

Cited By ~ 12

Author(s):

Karina Michalska ◽

Stanisław Ledakowicz

Keyword(s):

Anaerobic Digestion ◽

Chemical Oxygen Demand ◽

Volatile Fatty Acids ◽

Biogas Production ◽

Oxygen Demand ◽

Total Phenolic ◽

Methane Generation ◽

Pre Treatment ◽

Alkali Hydrolysis ◽

Almost All

AbstractThis work studies the influence of the alkali pre-treatment of Sorghum Moench — a representative of energy crops used in biogas production. Solutions containing various concentrations of sodium hydroxide were used to achieve the highest degradation of lignocellulosic structures. The results obtained after chemical pre-treatment indicate that the use of NaOH leads to the removal of almost all lignin (over 99 % in the case of 5 mass % NaOH) from the biomass, which is a prerequisite for efficient anaerobic digestion. Several parameters, such as chemical oxygen demand, total organic carbon, total phenolic content, volatile fatty acids, and general nitrogen were determined in the hydrolysates thus obtained in order to define the most favourable conditions. The best results were obtained for the Sorghum treated with 5 mass % NaOH at 121°C for 30 min The hydrolysate thus achieved consisted of high total phenolic compounds concentration (ca. 4.7 g L−1) and chemical oxygen demand value (ca. 45 g L−1). Although single alkali hydrolysis causes total degradation of glucose, a combined chemical and enzymatic pre-treatment of Sorghum leads to the release of large amounts of this monosaccharide into the supernatant. This indicates that alkali pre-treatment does not lead to complete cellulose destruction. The high degradation of lignin structure in the first step of the pre-treatment rendered the remainder of the biomass available for enzymatic action. A comparison of the efficiency of biogas production from untreated Sorghum and Sorghum treated with the use of NaOH and enzymes shows that chemical hydrolysis improves the anaerobic digestion effectiveness and the combined pre-treatment could have great potential for methane generation.

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