Biomass growth nutrients

In cases of still higher levels of BOD an additional supply of biomass may become essential, and this can be easily obtained from cowdung or municipal waste. To supplement biomass growth, nutrients such as urea and di-ammonium phosphate may be added. 

Using nonviable cellular biomass for azo dye removal has some advantages, namely the ability to function under extreme conditions of temperature and pH, and without addition of growth nutrients [10]. Also, waste yeast biomass, which is a by-product of industrial fermentations such as beer production, can be used as a relatively cheap source for biosorption of azo dyes. An important setback is the fact that the use of biomass for dye removal leads to an increase in the sludge amount, which requires further removal and treatment. 

Similarly, study is needed of the impact of large-scale biomass growth for feedstock for its impact on land use and any effect on nutrient runoff and eutrophication secondary to fertilizer demand (NRC, 2000). 

Another biomass approach is ocean fertilization. This method spurs biomass growth in areas that are low in productivity due to lack of critical nutrients. It, too, is limited in capacity, and has raised environmental concerns over changes in the natural food chain. The cost of biomass conversion is often quite low. Faustian et al.F l estimate that planting forests in developing countries could cost as low as US 3-10 per ton of CO2 captured. 

In the previous sections, the equations for phytoplankton and zooplankton biomass and nutrient concentration within one volume element have been formulated. The resulting equations are an attempt to describe the kinetics of the growth and death of the phytoplankton and zooplankton populations and their interaction with the nutrients available. The form of the equations for the volume V are as follows ... 

M. (1991) The effects of nutrients and temperature on biomass, growth, lipid production, and fatty acid composition of Cyclotella cryptica Reimann, Lewin, and Guillard. Appl Biochem. Biotechnol, 28-29, 317-326. 

The fast biomass growth facilitated the easy start-up of this system. By regulating the amount and type of nutrients, the biomass growth can be controlled. As a result, the start-up was carried out with only 4 m of seed sludge per 100 m of reactor volume. 

In order to analyze a biological process with a biomass, the starting point is the knowledge of the nutrient consumption rate, of the product generation rate and, especially, of the biomass growth rate. These different rates are related to each other through the stoichiometry of the reactions that take place inside the cells and, in a simple approach, they can be expressed by means of yield factors. Since the biomass growth is related to cell multiplication, its rate (per unit volume, for instance) can be set proportional to the biomass concentration X ... 

In any quantitative assessment of growth and/or product formation, it is essential to link formation of microbial biomass and products with the utilisation of substrate and nutrients. In the case of microbial biomass production, the total amount of cell mass yield formed is often proportional to the mass of substrate utilised. Mathematically this is coefficient expressed as the corresponding ratio, or yield coefficient ... 

We can see that for type 1 processes, high growth rate is obligately linked to a high rate of product formation. Indeed, this is the case for all products produced by a fermentative mode of metabolism, eg ethanol, lactic add, acetone. Chemostat studies have shown that for most aerobic processes when growth is limited by some nutrient other than the carbon source, the yield of product decreases with increase in spedfic growth rate (p or D p = dilution rate (D) in chemostat culture). Conversely, both the biomass yield and the spedfic rate of substrate utilisation (qs g substrate g biomass-1 h-1) increase with spedfic growth rate. 

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