Plant digestibility

Farm type of plant digester working volume (m3) mixing system heating system gas storage volume (m3) biogas use... 

Alkalinity and pH. Pilot-plant digesters at the University of Manitoba have operated successfully at pH levels up to 8.5 and at alkalinities ranging up to 14000 mg/L. These levels are well above those normally found in municipal digesters in which pH ranges of 7.2 to 7.6 and alkalinities of 1000 to 5000 mg/L normally occur. 

Their HP-500 Plus vessel system can handle 14 soil or plant digestions at a time. 

Fig. 7.3. Flow diagram for determination of nitrogen in plant digest solutions in...

CS028 Lancaster, L. A. and B. Rajadurai. An automated procedure for the determination of aluminum in soil and plant digest. J Sci Food Agr 1974 25 381. 

Li TSC, Harries D. Medicinal values of ginseng. Herb, Spice Medicinal Plant Digest 1996 14 1-5. 

Jaymen et al. [17] and other workers [18-20] found that aluminium in plant digests enhances the iron-1,10-phenanthroline colour, leading to high results in the determination of iron. Both the iron and aluminium complexes of phenanthroline exhibit identical absorption characteristics. Attempts to mask the aluminium in solution with sodium fluoride have been unsuccessful, as the fluoride ions suppress the colour formed with iron and reagent. The determination of iron after the separation of aluminium and phosphates is simple and rapid. This method is reliable and recoveries are quantitative. 

Gine et al. [29] has described a semi-automatic determination of manganese in plant digests using flow injection analysis. This technique utilises the introduction of the sample into a continuously flowing carrier stream of formaldoxime reagent. When injected, the sample is pushed by this stream and dispersed into the reagent stream, whereupon the required reaction takes place. The coloured complex is then carried into a spectrophotometric flow cell, where the absorbance is measured after an exactly defined time interval. 

For the analysis of plant digests, the acidic conditions of the samples were maintained in the carrier stream. Consequently, the sodium hydroxide concentration in the neutralisation stream was changed in order to achieve the required alkaline conditions in the final stream. 

Bismuth, antimony, arsenic, arsenate, vanadate, thallium, lead, tin, dichromate, nitrate and iron all interfere in this procedure but the interferences by all of these except thallium, tin and dichromate can be overcome by suitable modifications to the method. Plant digests for analysis when prepared by nitric acid-perchloric acid digestion [70]. 

Arsenic, Aluminium, Iron, Zinc, Chromium, Copper Plants Digestion with 2 + 1 v/v concentrated nitric acid and sulfuric acid As 0.5 ng/g Al, Fe, Zn, Cr, Cu 0.1 ng/g Flame AAS [95]... 

Plants Digest sample with nitric acid and analyze Spectro- photometer 7 g/L NA Dean 1989... 

With the majority of food products, copper can usually be determined by FAAS. In the few instances of low copper levels, resort has commonly been made to chelation—solvent extraction prior to FAAS measurement [8d, 34, 37m, 217] recent reports on the application of EAAS to analysis of foodstuffs and biological materials have appeared [193, 201, 204, 205, 223, 224], The importance of non-atomic absorption in the determination of copper in plant digests by FAAS has been studied by Simmons [225]. Correction was necessary to arrive at good results, with a continuum light source providing more accurate data than use of a nearby non-absorbing line. 

Acidity and alkalinity are two important parameters that must be controlled in the operation of a wastewater treatment plant. Digesters, for example, will not operate if the environment inside the tank is acidic, since microorganisms will simply die in acid environments. The contents of the tank must be buffered at the proper acidity as well as proper alkalinity. 

FIGURE 2.5 A flow injection system for the potentiometric determination of ammonium in Kjeldahl plant digests used in Brazil in 1976. The flow setup is supported by LEGO blocks and includes a needleless syringes for manual sample injection, an air-gap ammonium electrode (in white), a model 8511 Polymetron peristaltic pump and a model 64 Radiometer pH meter (recorder not shown). For experimental details, see Ref. [43],... 

J.W.B. Stewart, J. Ruzicka, H. Bergamin-Filho, E.A.G. Zagatto, Flow injection analysis. Part III. Comparison of continuous flow spectrophotometry and potentiomety for the rapid determination of total nitrogen content in plant digests, Anal. Chim. Acta 81... 

B.F. Reis, M.F. Cine, F.J. Krug, H. Bergamin-Filho, Multipurpose flow-injection system. Part 1. Programmable dilutions and standard additions for plant digests analysis by inductively coupled plasma atomic emission spectrometry, J. Anal. At. Spectrom. 7 (1992) 865. 

B.F. Reis, M.F. Gine, E.A.G. Zagatto, J.L.F.C. Lima, R.A.S. Lapa, Multicommutation in flow analysis. Part 1. Binary sampling concepts, instrumentation and spectrophoto-metric determination of iron in plant digests, Anal. Chim. Acta 293 (1994) 129. 

F.J. Krug, E.A.G. Zagatto, B.F. Reis, O. Bahia-Filho, A.O. Jacintho, S.S. Jorgensen, Turbidimetric determination of sulphate in plant digests and natural waters by flow injection analysis with alternating streams, Anal. Chim. Acta 145 (1983) 179. 

Worked example 4. A confluence flow injection system with a very low confluent stream flow rate is designed for the spectrophotometric determination of phosphate in plant digests. The linearity of the analytical calibration graph is good and the recorded absorbance corresponding to a 100.0 mg L 1 P (as phosphate) standard solution is 0.21. Replacing the sample carrier stream by this standard solution (sample infinite volume) yields a steady state situation and the related absorbance is 0.68. The pump is then turned off and an asymptotic increase in absorbance towards 0.95 is observed determine the sensitivity improvement that in principle could be attained simply by increasing the sample volume and the mean sample residence time in the analytical path. 

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