Silage liquids

Chemical analysis shows that the dry residue of silage liquids ranges from 3 to 9%. Organic matter in the dry residue ranges from 85 to 90%, the ash content makes 10-15% of dry residue. 

Silage liquids, except the liquids from clover silage, contain rather a low amount of nitrogen (0.03-0.28%) and about half of this is in the ammonia form. From the aspects of nutrients the potassium content is also significant (0.10-0.37%) whereas the quantities of other nutrients (P, Ca, Mg) are very low. Silage liquids, however, have unfavourable effects particularly on stagnant surface waters (eutrophization). 

Silage liquids are noted for quite high acidity, the pH value ranging from 4.2 to 4.9. The concentration of organic acids which degrade in streams and wastewater treatment plants quite quickly, ranges from 7 to 12 g 1 . Therefore it is necessary to apply lime to soil when these acids are used as fertilizers. 

The characteristic properties of silage liquid produced during silaging of beet leaves are presented in Table 3.65. 

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Another source of pollution of animal origin is silage liquids produced during preservation of green fodder by silaging. About 5% of the produced quantity of silage liquids is introduced into the streams. 

Table 3.65. Characteristic properties of silage liquid from silage of beet leaves... 

There are two possibilities dry feed - e.g., fish meal and liquid feed -e.g., fish silage (protein hydrolyzates) [7]. In this research the utilization of sludge for fish silage production has been investigated. 

Fish silage is usually produced from fish offals (heads, intestines, skin, etc.) or waste fish. The enzymes present in fish viscera decompose these tissues and the liquid protein hydrolyzate is the final product [9-11]. To avoid bacteria growth a pH about 2 is required and a relevant amount of organic or inorganic acid is added, usually it is sulphuric acid. The idea was to supply a certain amount of post-coagulation sludge for silage production [12]. 

Canale, A., Valente, M.E. and Ciotti, A. (1984) Determination of volatile carboxylic acids (C i-Cj.) and lactic acid in aqueous extracts of silage by high performance liquid chromatography. Journal of the Science of Food and Agriculture 35, 1178-1182. 

Suzuki, M. and Lund, C.W. (1980) Improved gas-liquid chromatography for simultaneous determination of volatile fatty acids and lactic acid in silage. Journal of Agricultural and Food Chemistry 28,... 

The enzymatic convertibility of the solid fraction after pretreatment was determined for the pretreated materials as well as for the untreated maize silage. The enzymatic hydrolysis was carried out at 50 °C, pH 4.8, with 2% DM and an enzyme load of 30 FPU/g DM. The enzyme used was Cellubiix L (Novozymes, Denmark) and the amounts of hydrolyzed sugars were determined by high-performance liquid chromatography (HPLC see Analysis... 

Maize silage was pretreated by wet oxidation and hydrothermal treatment as described in Table 1. The sugar recoveries based on analysis and overall mass balance of the pretreated fractions (solid fibers and liquid) and the raw material have been calculated according to Eq. 1, and the results are shown in Fig. 1. The total recovery of glucose was very close to a 100% in all experiments (not shown), while the recovery of hemicellulose sugars depended very much on pretreatment conditions. 

Wet forms of biomass, such as sewage, liquid manure and silage, would normally be treated by anaerobic digestion at ambient temperature. The resulting biogas is a mixture of methane, carbon monoxide and carbon dioxide, with rather little hydrogen. It is similar to the biogas produced in... 

Figure 6.8 Biogas biorefinery Gut Hulsenberg GmbH, Germany. Substrates Cattle manure, silage of corn, rye,and perennial grasses. Production of6450 Mwhei, 6880 MWhth and 22,000 m of liquid organic fertilizer peryear.

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