Biochemical methane potential (BMP) of solid organic materials: results obtained from an international interlaboratory study

International audienceThis paper describes the results obtained for different participating research groups in an interlaboratory study related to the biochemical methane potential (BMP). In this research work, the full experimental conditions influencing the test such as inoculum, substrate characteristics and experimental conditions were reported. The study was performed using 4 samples: 3 reference substrates (starch, cellulose and gelatine), and 1 raw material (mung bean). The BMP of mung bean was carried out at two inoculum to substrate ratios (ISR), specifically 2 and 1. The methane yields of reference substrates for starch, cellulose and gelatine were 352±33, 353±29 and 382±42 mL/g VSadded, respectively. The percentages of biotransformation of these substrates into methane were 85±8, 85±7 and 88±10%, respectively. On the other hand, the values of methane yields and biodegradability for MB were 373±35 mL CH4/g VSadded and 86±8%, respectively. In addition, the anaerobic digestion of the raw material selected did not show influence on the ISR in the extent of the biotransformation

Biochemical methane potential (BMP) of solid organic materials: results obtained from an international interlaboratory study

International audienceThis paper describes the results obtained for different participating research groups in an interlaboratory study related to the biochemical methane potential (BMP). In this research work, the full experimental conditions influencing the test such as inoculum, substrate characteristics and experimental conditions were reported. The study was performed using 4 samples: 3 reference substrates (starch, cellulose and gelatine), and 1 raw material (mung bean). The BMP of mung bean was carried out at two inoculum to substrate ratios (ISR), specifically 2 and 1. The methane yields of reference substrates for starch, cellulose and gelatine were 352±33, 353±29 and 382±42 mL/g VSadded, respectively. The percentages of biotransformation of these substrates into methane were 85±8, 85±7 and 88±10%, respectively. On the other hand, the values of methane yields and biodegradability for MB were 373±35 mL CH4/g VSadded and 86±8%, respectively. In addition, the anaerobic digestion of the raw material selected did not show influence on the ISR in the extent of the biotransformation

Quality improvement in determination of chemical oxygen demand in samples considered difficult to analyze, through participation in proficiency-testing schemes

Chemical oxygen demand (COD) is a critical analytical parameter in waste and wastewater treatment, more specifically in anaerobic digestion, although little is known about the quality of measuring COD of anaerobic digestion samples. Proficiency testing (PT) is a powerful tool that can be used to test the performance achievable in the participants' laboratories, so we carried out a second PT of COD determination in samples considered " difficult" to analyze (i.e. solid samples and liquid samples with high concentrations of suspended solids). The results obtained (based on acceptable z-score values) may be considered satisfactory. When compared with the results of a previous similar scheme, the overall performance improved by around 30%, again demonstrating that analytical performance can be improved by regular participation in PT.La demande chimique en oxyg\ue8ne (DCO) [COD en anglais] constitue un param\ue8tre analytique essentiel dans le traitement des d\ue9chets et des eaux us\ue9es, plus particuli\ue8rement dans la digestion ana\ue9robie. Toutefois, on sait peu de choses sur la qualit\ue9 des mesures de la DCO d\u2019\ue9chantillons de digestion ana\ue9robie. L\u2019essai d\u2019aptitude (EA) [Proficiency testing ou PT en anglais] est un outil puissant utilisable pour v\ue9rifier la performance que l\u2019on peut obtenir dans les laboratoires participants. Nous avons donc men\ue9 un deuxi\ue8me EA pour d\ue9terminer la DCO d\u2019\ue9chantillons jug\ue9s \uab difficiles \ubb \ue0 analyser (c\u2019est-\ue0-dire des \ue9chantillons solides et des \ue9chantillons liquides ayant une concentration \ue9lev\ue9e de particules solides en suspension). Les r\ue9sultats obtenus (fond\ue9s sur des scores z acceptables) peuvent \ueatre consid\ue9r\ue9s comme satisfaisants. En les comparant avec des r\ue9sultats obtenus ant\ue9rieurement dans un syst\ue8me similaire, la performance globale s\u2019est am\ue9lior\ue9e d\u2019environ 30 %, d\ue9montrant une fois de plus qu\u2019il est possible d\u2019am\ue9liorer la performance analytique en participant r\ue9guli\ue8rement \ue0 des EA.Peer reviewed: YesNRC publication: Ye