scholarly journals How Different Are Manometric, Gravimetric, and Automated Volumetric BMP Results?

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1839 ◽  
Author(s):  
Corrado Amodeo ◽  
Sasha D. Hafner ◽  
Rúben Teixeira Franco ◽  
Hassen Benbelkacem ◽  
Paul Moretti ◽  
...  
Keyword(s):  
Automated System ◽  
Biochemical Methane Potential ◽  
Ch4 Production ◽  
Automated Method ◽  
Validation Criteria ◽  
Relative Standard ◽  
Mode 2 ◽  
Methane Potential ◽  
Manual Methods ◽  
The Mean

The objectives of this study were to: (1) quantify differences in biochemical methane potential (BMP) measured using three measurement methods, including two popular methods (a commercial automated system (AMPTS II) and manual manometric) and one newer method (gravimetric), and (2) assess the importance of the mixing position in the measurement sequence. Powdered microcrystalline cellulose was used as the substrate in simultaneous tests. All methods gave similar results (<8% difference in the mean BMP) and were reasonably accurate (recovery of 80–86% of the theoretical maximum BMP). Manometric BMP values were consistently lower than gravimetric by 4–5%. Precision was lower for the automated method (relative standard deviation (RSD) of about 7%) than for the manual methods (RSD about 1–3%). Mixing after biogas measurement resulted in 3% higher BMP for both manual methods than mixing before, due to the lower measured CH4 production from blanks. This effect may be linked to a fraction of CH4 that remains dissolved or even as attached bubbles, and suggests that mixing before measurement is preferable. The automated volumetric and gravimetric methods (mode 2) gave very similar mean BMP values (1% different). However, kinetic analysis showed that methane production was faster with the automated volumetric method. This could come from an error in the estimation of the CH4 production rate for the automated method, or an increase in the degradation rate due to better mixing. Both automatic volumetric and manual gravimetric measurements met current validation criteria for mean cellulose BMP, but the RSD from the automated system exceeded the limit.

scholarly journals Improving Inter-Laboratory Reproducibility in Measurement of Biochemical Methane Potential (BMP)

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1752 ◽  
Author(s):  
Sasha D. Hafner ◽  
Hélène Fruteau de Laclos ◽  
Konrad Koch ◽  
Christof Holliger
Keyword(s):  
Standard Deviation ◽  
Data Processing ◽  
Relative Standard Deviation ◽  
Measurement Methods ◽  
Test Duration ◽  
Organic Substrates ◽  
Biochemical Methane Potential ◽  
Validation Criteria ◽  
Relative Standard ◽  
Methane Potential

Biochemical methane potential (BMP) tests used to determine the ultimate methane yield of organic substrates are not sufficiently standardized to ensure reproducibility among laboratories. In this contribution, a standardized BMP protocol was tested in a large inter-laboratory project, and results were used to quantify sources of variability and to refine validation criteria designed to improve BMP reproducibility. Three sets of BMP tests were carried out by more than thirty laboratories from fourteen countries, using multiple measurement methods, resulting in more than 400 BMP values. Four complex but homogenous substrates were tested, and additionally, microcrystalline cellulose was used as a positive control. Inter-laboratory variability in reported BMP values was moderate. Relative standard deviation among laboratories (RSDR) was 7.5 to 24%, but relative range (RR) was 31 to 130%. Systematic biases were associated with both laboratories and tests within laboratories. Substrate volatile solids (VS) measurement and inoculum origin did not make major contributions to variability, but errors in data processing or data entry were important. There was evidence of negative biases in manual manometric and manual volumetric measurement methods. Still, much of the observed variation in BMP values was not clearly related to any of these factors and is probably the result of particular practices that vary among laboratories or even technicians. Based on analysis of calculated BMP values, a set of recommendations was developed, considering measurement, data processing, validation, and reporting. Recommended validation criteria are: (i) test duration at least 1% net 3 d, (ii) relative standard deviation for cellulose BMP not higher than 6%, and (iii) mean cellulose BMP between 340 and 395 NmLCH4 gVS−1. Evidence from this large dataset shows that following the recommendations—in particular, application of validation criteria—can substantially improve reproducibility, with RSDR < 8% and RR < 25% for all substrates. The cellulose BMP criterion was particularly important. Results show that is possible to measure very similar BMP values with different measurement methods, but to meet the recommended validation criteria, some laboratories must make changes to their BMP methods. To help improve the practice of BMP measurement, a new website with detailed, up-to-date guidance on BMP measurement and data processing was established.

scholarly journals Development and Validation of a Low-Cost Gas Density Method for Measuring Biochemical Methane Potential (BMP)

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2431 ◽  
Author(s):  
Camilla G. Justesen ◽  
Sergi Astals ◽  
Jacob R. Mortensen ◽  
Rasmus Thorsen ◽  
Konrad Koch ◽  
...  
Keyword(s):  
Mass Loss ◽  
Low Cost ◽  
Accurate Determination ◽  
Automated System ◽  
Biochemical Methane Potential ◽  
Laboratory Equipment ◽  
Gas Density ◽  
Relative Standard ◽  
Methane Potential ◽  
Development And Validation

Accurate determination of biochemical methane potential (BMP) is important for both biogas research and practice. However, access to laboratory equipment limits the capacity of small laboratories or biogas plants to conduct reliable BMP assays, especially in low- and middle-income countries. This paper describes the development and validation of a new gas density-based method for measuring BMP (GD-BMP). In the GD-BMP method, biogas composition is determined from biogas density. Biogas density is based on bottle mass loss and biogas volume, and these can be accurately measured using only a standard laboratory scale, inexpensive syringes, and a simple manometer. Results from four experiments carried out in three different laboratories showed that the GD-BMP method is both accurate (no significant bias compared to gravimetric or volumetric methods with biogas analysis by gas chromatography) and precise (<3% relative standard deviation is possible). BMP values from the GD-BMP method were also comparable to those measured for the same substrates with an industry standard automated system (AMPTS II) in two independent laboratories (maximum difference 10%). Additionally, the GD-BMP method was shown to be accurate even in the presence of leakage by excluding leakage from mass loss measurements. The proposed GD-BMP method represents a significant breakthrough for both biogas research and the industry. With it, accurate BMP measurement is possible with only a minimal investment in supplies and equipment.

scholarly journals Missouri Automated Nitrogen Method (MANM) for Fertilizers

1972 ◽  
Vol 55 (3) ◽  
pp. 467-480
Author(s):  
Charles W Gehrke ◽  
John S Killingley ◽  
Larry L Wall
Keyword(s):  
Standard Deviation ◽  
Total Nitrogen ◽  
Primary Standard ◽  
Relative Difference ◽  
Automated System ◽  
Urea Nitrogen ◽  
Average Value ◽  
Color Development ◽  
Automated Method ◽  
Relative Standard

Abstract An automated spectrophotometric method, utilizing Technicon AutoAnalyzer modules, has been developed to determine total nitrogen in fertilizers containing only ammoniacal, nitrate , and urea nitrogen. This colorimetric system employs the Berthelot ammoniaphenate- hypochlorite reaction. A homogeneous chromous/titanous reduction system for the automatic reduction of nitrates was interfaced with the digestion unit and color development manifold, resulting in a total nitrogen system for fertilizers with an effective analysis r a t e of 20-25 samples/hr. A new sample retrieval system removes digested samples from the helix. The totally automated system was optimized to obtain t h e highest sensitivity for nitrogen. Data were compared for 458 samples analyzed by the automated method and the comprehensive nitrogen method (CNM), 2.053–2.054. The average difference between the 2 methods (MANM – CNM) was +0.04% nitrogen. The average relative difference was 1.12%. The average value for 140 samples of KNO3 primary standard analyzed by the MANM was 13.84% nitrogen (theoretical content 13.85%). The results of these standards ranged from 13.58 to 14.14% nitrogen and the standard deviation was 0.11%. The relative standard deviation was 0.80%. Of fertilizer samples received for analysis, less than 1% contained insoluble organic nitrogenous material which was unsuitable for analysis by the MANM. These few samples were not included in the statistical evaluation. The MANM is rapid, accurate, and precise and is a convenient and dependable automated method for the determination of total nitrogen in fertilizers containing only ammoniacal, nitrate , and urea nitrogen.

Automated Chemical Determination of Methionine

1974 ◽  
Vol 57 (3) ◽  
pp. 682-688
Author(s):  
Charles W Gehrke ◽  
Terry E Neuner
Keyword(s):  
Amino Acid ◽  
Standard Deviation ◽  
Ion Exchange ◽  
Automated System ◽  
Automated Method ◽  
Relative Standard ◽  
Chemical Determination ◽  
Sample Recovery ◽  
Hydrolysis Of

Abstract A rapid, accurate, and precise spectrophotometry method, based on the nitroprussidemethionine color reaction, has been developed for the determination of methionine in soybeans, mungbeans, and corn. Amino acid interference was eliminated by partial enzymatic hydrolysis of samples for 4 hr at 50 °C with papain; the samples were analyzed by an automated system. Precision and accuracy were determined by repeated independent analyses of 13 samples of corn, mungbeans, and soybeans; the data were compared to independent classical ion exchange amino acid results. The range for each set of samples varied from 0.02 to 0.04 w/w% methionine. The per cent recovery for 12 of the 13 samples compared to those from ion exchange ranged from 95.2 to 107.1% with an average of 100.2%. The standard deviation varied from 0.01 to 0.02, and the per cent relative standard deviation from 11.8% for a 0.16 w/w% sample to 2.5% for a 0.42 w/w% sample. Recovery of added methionine from corn samples ranged from 92.7 to 102.0% (96.8% average) ; from soybeans 95.0 to 112.0% (101.9% average); and from mungbeans 91.3 to 102.0% (95.8% average). A reliable automated method has been developed which is applicable to different types of biological substances; 20 samples/hr can be analyzed.

Hydroxylamine Hydrochloride in Automated and Manual Methods for Riboflavin Determination

1977 ◽  
Vol 60 (1) ◽  
pp. 147-150
Author(s):  
Barabara S Jacobson
Keyword(s):  
Hydrogen Peroxide ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Flow System ◽  
Hydroxylamine Hydrochloride ◽  
Automated System ◽  
Relative Standard ◽  
Aoac Method ◽  
Manual Methods ◽  
Oxygen Gas

Abstract The AOAC method for riboflavin determination has been modified to improve the precision of the manual method and greatly simplify its automation. In the AOAC method, permanganate oxidation is used for sample cleanup, and hydrogen peroxide is used to reduce excess permanganate. By substituting hydroxylamine. HCl for the hydrogen peroxide, the generation of oxygen gas, which can be troublesome, is eliminated without otherwise changing the assay. The resulting manual assay has a relative standard deviation of 1% as opposed to 2.5% for the same assay with hydrogen peroxide. This method is simple to automate, using a continuous flow system. The automated system performs 40 determinations per hour with a 1% relative standard deviation and results agree with those from the AOAC method at the 98% confidence level.

scholarly journals Biogas Potential of Coffee Processing Waste in Ethiopia

2018 ◽  
Vol 10 (8) ◽  
pp. 2678 ◽  
Author(s):  
Bilhate Chala ◽  
Hans Oechsner ◽  
Sajid Latif ◽  
Joachim Müller
Keyword(s):  
Waste Water ◽  
Thermal Energy ◽  
Anaerobic Fermentation ◽  
Combined Heat And Power ◽  
Neutral Detergent Fiber ◽  
Anaerobic Performance ◽  
Processing Waste ◽  
Biochemical Methane Potential ◽  
Methane Potential ◽  
The Mean

Primary coffee processing is performed following the dry method or wet method. The dry method generates husk as a by-product, while the wet method generates pulp, parchment, mucilage, and waste water. In this study, characterization, as well as the potential of husk, pulp, parchment, and mucilage for methane production were examined in biochemical methane potential assays performed at 37 °C. Pulp, husk, and mucilage had similar cellulose contents (32%). The lignin contents in pulp and husk were 15.5% and 17.5%, respectively. Mucilage had the lowest hemicellulose (0.8%) and lignin (5%) contents. The parchment showed substantially higher lignin (32%) and neutral detergent fiber (96%) contents. The mean specific methane yields from husk, pulp, parchment, and mucilage were 159.4 ± 1.8, 244.7 ± 6.4, 31.1 ± 2.0, and 294.5 ± 9.6 L kg−1 VS, respectively. The anaerobic performance of parchment was very low, and therefore was found not to be suitable for anaerobic fermentation. It was estimated that, in Ethiopia, anaerobic digestion of husk, pulp, and mucilage could generate as much as 68 × 106 m3 methane per year, which could be converted to 238,000 MWh of electricity and 273,000 MWh of thermal energy in combined heat and power units. Coffee processing facilities can utilize both electricity and thermal energy for their own productive purposes.

scholarly journals Evaluation of an Automated Method for Analysing the Electromyogram

1978 ◽  
Vol 5 (3) ◽  
pp. 275-281 ◽  
Author(s):  
R.E.P. Sica ◽  
A.J. McComas ◽  
J.C.D. Ferreira
Keyword(s):  
Interference Pattern ◽  
Action Potentials ◽  
Biceps Brachii ◽  
Automated System ◽  
Vastus Medialis ◽  
Muscle Action ◽  
Mean Values ◽  
Automated Method ◽  
The Mean

SUMMARYAn automated system, incorporating the ANOPS-101 mini-computer, has been used to analyse the EMG. The vastus medialis (VM) and biceps brachii (BB) muscles were studied in 28 controls, 16 patients with myopathies, and in 26 patients with denervating disorders. For each muscle mean values were computed for the durations and numbers of phases of muscle action potentials; the mean density and amplitude of the deflections in the interference pattern were also measured. A higher incidence of abnormalities could be detected in myopathic than in neuropathic disorders; for both conditions the incidence was significantly greater in BB than in VM. For the diagnosis of denervation the most useful measurement was that of potential duration; for the detection of myopathies amplitude determinations were also very useful. The present results have been compared with those of other published studies in which automatic EMG analysis has been employed.

Anaerobic codigestion of the mechanically sorted organic fraction of a municipal solid waste with cattle manure in packed microcosms under batch conditions

2008 ◽  
Vol 58 (9) ◽  
pp. 1735-1742 ◽  
Author(s):  
L. Bertin ◽  
D. Todaro ◽  
C. Bettini ◽  
F. Fava
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Suspended Solids ◽  
Cattle Manure ◽  
Lag Phase ◽  
Organic Fraction ◽  
Biochemical Methane Potential ◽  
Ch4 Production ◽  
Anaerobic Codigestion ◽  
Methane Potential

Packed microcosms, consisting of 0.6 L-flask filled with tire chips (TC, a non-cost-recyclable non-biodegradable material) or ceramic cubes, were employed in the wet batch mesophilic anaerobic codigestion of a mechanically sorted organic fraction of a municipal solid waste with cattle manure. Two different waste mixtures were digested within four successive batch experiments, performed by collecting the digested waste and by refilling each microcosm with the same experimental mixture. Methane production yields related to the first experiment were comparable to those of non-packed identically developed microcosms, while they significantly grew during all the following experiences. No CH4-production lag-phase was observed since the second batch experiment. Similar results were obtained for both packing materials: however, the highest methane yields were achieved within bioreactors packed with TC in the presence of a mixture in which the volatile suspended solids (VSS) provided by the municipal waste represented the 55% of the total ones. Under such condition, a methane yield corresponding to the biochemical methane potential (BMP) calculated through a 6-month experiment with non-packed microcosms (176 ml/gVS) was attained in about 1/4 of the time. Importantly, the BMP can significantly grow up as a consequence of the approach described in this study.

Automated Fluorometric Determination of Thiamine and Riboflavin in Infant Formulas

1979 ◽  
Vol 62 (3) ◽  
pp. 642-647
Author(s):  
Walter E Dunbar ◽  
Kenneth E Stevenson
Keyword(s):  
Sample Preparation ◽  
Infant Formulas ◽  
Fluorometric Method ◽  
Fluorometric Determination ◽  
Automated Method ◽  
Coefficients Of Variation ◽  
Manual Methods ◽  
The Mean ◽  
Better Than

Abstract Commercial infant formulas were analyzed simultaneously for thiamine and riboflavin by an automated fluorometric method and by the AOAC manual fluorometric methods. For 10 products, the mean thiamine and riboflavin results determined using the automated method ranged from 104 to 113% and 90 to 112%, respectively, of those by the AOAC manual methods. The coefficients of variation for thiamine and riboflavin ranged from 1.05 to 3.90% and 0.60 to 2.48%, respectively, for the automated method, and 1.48 to 3.86% and 0.69 to 10.9%, respectively, for the manual methods. Using the automated method, mean recoveries of thiamine and riboflavin added to samples were 103 and 104%, respectively. The automated method used a common sample preparation to determine both thiamine and riboflavin, and gave results equivalent to, or better than, those obtained by the manual methods.

INFLUENCE OF FREEZING/THAWING AND DRYING/MILLING ON BIOCHEMICAL METHANE POTENTIAL

2016 ◽  
Vol 15 (7) ◽  
pp. 1533-1536
Author(s):  
Jin Mi Triolo ◽  
Sven Gjedde Sommer ◽  
Lene Pedersen
Keyword(s):  
Biochemical Methane Potential ◽  
Methane Potential
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