Search results for "Kjeldahl method"
showing 9 items of 9 documents
A microscale Kjeldahl nitrogen determination for environmental waters.
2008
A microscale Kjeldahl system has been designed which has been homemade reduced. The digestor unit of a macroKjeldahl system and a modified glassware microdistillation unit have been used. The optimal conditions for digestion and distillation have been established for ammonium and methylamine as model compound of organic amino nitrogen. The optimised procedure has been applied to the determination of Kjeldahl nitrogen in water samples. Recoveries near 100% and good precision have been achieved. This procedure combines nitrogen miniaturized system and the use of a selective ion electrode for ammonia detection. The analysis time was reduced 4.8 times and the analysis cost 6.6 times compared wi…
Detailed internal characterisation of two Finnish landfills by waste sampling
2006
The aim of this study was to characterise the internal structure and composition of landfilled waste at two Finnish landfills to provide information for active and post-landfill operations. The two sites, Ammässuo and Kujala, have been in operation for 17 and 48 years, respectively. Waste was sampled (total 68 samples) and analysed for total solids (TS), volatile solids (VS), total Kjeldahl nitrogen (TKN), biological methane potential (BMP) and leaching of organic material (determined as chemical oxygen demand, COD) and ammonium nitrogen (NH(4)-N). The results showed high vertical and horizontal variability, which indicated that both the waste composition and state of degradation varied gre…
Selective determination of ammonium in water based on HPLC and chemiluminescence detection
2005
Abstract A selective and sensitive method has been developed for liquid chromatographic determination of ammonium in water samples. The analyte is derivatized with Dansyl Chloride prior to injection into HPLC. Optimal solution derivatization conditions have been established. The dansyl derivative is separated with the aid of a chromatographic column and post-column mixed with peroxyoxalate (TCPO) and H 2 O 2 in order to perform chemiluminescence detection. The detection limit achieved is 8 μg/L and linear response from 0.027 to 0.750 mg/L of ammonium was obtained. Ammonium ion was determined within 2.4 min under optimum chromatographic conditions. The method is fast, and near 10 derivatized…
Mesophilic and thermophilic anaerobic co-digestion of rendering plant and slaughterhouse wastes.
2011
Co-digestion of rendering and slaughterhouse wastes was studied in laboratory scale semi-continuously fed continuously stirred tank reactors (CSTRs) at 35 and 55 °C. All in all, 10 different rendering plant and slaughterhouse waste fractions were characterised showing high contents of lipids and proteins, and methane potentials of 262-572 dm(3)CH(4)/kg volatile solids(VS)(added). In mesophilic CSTR methane yields of ca 720 dm(3) CH(4)/kg VS(fed) were obtained with organic loading rates (OLR) of 1.0 and 1.5 kg VS/m(3) d, and hydraulic retention time (HRT) of 50 d. For thermophilic process, the lowest studied OLR of 1.5 kg VS/m(3) d, turned to be unstable after operation of 1.5 HRT, due to ac…
Two-stage anaerobic digestion of tomato, cucumber, common reed and grass silage in leach-bed reactors and upflow anaerobic sludge blanket reactors
2010
Abstract Anaerobic digestion of tomato, cucumber, common reed and grass silage was studied in four separate two-stage reactor configuration consisting of leach bed reactor (LBR) and upflow anaerobic sludge blanket reactor (UASB). LBR studies showed that COD solubilization for cucumber and grass silage was higher (50%) than tomato (35%) and common reed (15%). Results also showed that 31–39% of initial TKN present in tomato and cucumber was solubilized in the leachates and 47–54% of the solubilized TKN was converted to NH4-N. The corresponding values for common reed and grass silage were 38–50% and 18–36%, respectively. Biomethanation of the leachates in UASB reactors resulted in methane yiel…
Long-term thermophilic mono-digestion of rendering wastes and co-digestion with potato pulp
2014
In this study, mono-digestion of rendering wastes and co-digestion of rendering wastes with potato pulp were studied for the first time in continuous stirred tank reactor (CSTR) experiments at 55°C. Rendering wastes have high protein and lipid contents and are considered good substrates for methane production. However, accumulation of digestion intermediate products viz., volatile fatty acids (VFAs), long chain fatty acids (LCFAs) and ammonia nitrogen (NH4-N and/or free NH3) can cause process imbalance during the digestion. Mono-digestion of rendering wastes at an organic loading rate (OLR) of 1.5 kg volatile solids (VS)/m(3)d and hydraulic retention time (HRT) of 50 d was unstable and resu…
Thermophilic anaerobic digestion of pulp and paper mill primary sludge and co-digestion of primary and secondary sludge
2012
Anaerobic digestion of pulp and paper mill primary sludge and co-digestion of primary and secondary sludge were studied for the first time in semi-continuously fed continuously stirred tank reactors (CSTR) in thermophilic conditions. Additionally, in batch experiments, methane potentials of 210 and 230 m³CH₄/t volatile solids (VS)(added) were obtained for primary, and 50 and 100 m³CH₄/tVS(added) for secondary sludge at 35 °C and 55 °C, respectively. Anaerobic digestion of primary sludge was shown to be feasible with organic loading rates (OLR) of 1-1.4 kgVS/m³d and hydraulic retention times (HRT) of 16-32 d resulting in methane yields of 190-240 m³CH₄/tVS(fed). Also the highest tested OLR o…
Lineare polyester mit alkoholischen endgruppen und deren bestimmung
1955
Lineare Bernsteinsaure-1,6-Hexandiol-Polyester mit alkoholischen Endgruppen werden mit einem uberschus des Diols durch Schmelz- und durch Losungskondensation hergestellt. Hohermolekulare Polyester mit uberwiegend alkoholischen Endgruppen werden durch. Nachkondensation mit dem Diol erhalten. Die Umsetzung der Produkte mit Phenylisocyanat fuhrt zu Polyesterdiurethanen. Die Ermittlung des Stickstoffs nach Kjeldahl liefert mit befriedigender Genauigkeit Endgruppenmolekulargewichte bis zum Molgewicht ∼5 · 103. Bei der Totalhydrolyse der Polyesterdiurethane bildet sich Anilin, das mit einem empfindlichen, photometrischen Verfahren quantitative erfast wird. Aus der so bestimmten Anilinmenge wurden…
Determination of ammonia and primary amine compounds and Kjeldahl nitrogen in water samples with a modified Roth's fluorimetric method.
2005
Abstract A method for the simultaneous determination of primary amino groups and ammonium ion has been proposed. The method is based in solution derivatization with o-Phthaldialdehyde/N-acetyl-cisteine (OPA/NAC) and fluorescence measurement of the formed isoindols. Analytical characteristics and description of the developed procedure have been provided. The calibration graphs for ammonium (up to 1.44 mg L−1 of N) and methylamine as primary amino model compound (up to 0.282 mg L−1 of N), were obtained. Bivariate and multivariate calibration models have been tested. The limits of detection were 0.07 mg L−1 of N and 0.004 mg L−1 of N for ammonium and amine, respectively. The procedure was firs…