Biomass growth yield

Human activity, particularly in the developing world, continues to make it more difficult to sustain the world s biomass growth areas. It has been estimated that tropical forests are disappearing at a rate of tens of thousands of hm per year. Satellite imaging and field surveys show that Brazil alone has a deforestation rate of approximately 8 x 10 hm /yr (5). At a mean net carbon yield for tropical rain forests of 9.90 t/hm yr (4) (4.42 short ton /acreyr), this rate of deforestation corresponds to a loss of 79.2 x 10 t/yr of net biomass carbon productivity. 

If the growth yield coefficient for ammonia was 10 g g 1, what concentration of biomass would you expect if ammonia was added to a concentration of 2-5 g l 1 ... 

Suspended biomass growth results in the removal of readily biodegradable substrate. A yield constant, YHw, typically about 0.55 g COD biomass produced... 

It should be noticed that biomass growth and respiration for bulk water phase include details that are not taken into account in the simple half-order biofilm description. As an example and a consequence, the two yield constants, YHw and Yup are differently interpreted in terms of the substrate requirement of the biomass (Figure 5.5). 

The rates of uptake of substrate and oxygen are related to the biomass growth rate by appropriate yield constants ... 

A limitation of the methods described so far is that they have assumed a constant overall yield coefficient and do not allow the endogenous respiration coefficient kd (or alternatively the maintenance coefficient, m) to be evaluated. Equation 5.54 shows that the overall yield, as measured when monitoring a batch reactor, is affected by the growth rate and has the greatest impact when the growth rate is low. Consequently, it is desirable to be able to estimate the values of kd or m, so that the yield coefficient reflects the true growth yield. An equivalent method would be one where the specific rates of formation of biomass and consumption of substrate were determined independently, again without the assumption of a constant overall yield-coefficient. 

The ethanol yield, V[ ,0[, (g/g), was calculated as the produced ethanol after the depletion of glucose and mannose divided by the amount of consumed fermentable sugar (glucose and mannose). The anaerobic growth yield, Yx (g/ g), hereafter referred to as the biomass yield, was calculated as the produced biomass in 36 h divided by the amount of fermentable sugars initially present. 

Stauffer, M.D., Chubey, B.B., and Dorrell, D.G., Growth, yield and compositional characteristics of Jerusalem artichoke as they relate to biomass production, in Fuels from Biomass and Wastes, Klass, D.L. and Emert, G.H., Eds., Ann Arbor Science, Ann Arbor, MI, 1981, pp. 79-97. 

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