Biomass growth estimated

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. 

This growth expression requires a minimum of kinetics and stoichiometric coefficients to be determined, and no hydraulic details are included. The dynamics of sewer biofilm detachment are not quantitatively known, and a steady state biofilm with a biomass release to the bulk water phase, equal to the biomass growth within the biofilm, is therefore an estimate. 

Due to the complexity of bioprocesses, and the lack of direct in-process measurements of critical process variables, much work is being done on development of soft sensors and model predictive control of such systems. Soft sensors have long been used to estimate biomass concentration in fed-batch cultivations. The soft sensors can be integrated into automated control structures to control the biomass growth in the fermentation. 

Bacterial growth efficiency (BGE), i.e., the efficiency at which bacterioplankton convert OC into bacterial biomass was calculated from the rate of decline in substrate (OC) and the rate of increase in bacterial biomass (BB) estimated from bacterial production as follow ... 

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. 

The dominant source of organic carbon in seawater is the photosynthetic fixation of C02 by unicellular algae (phytoplankton) in the photic zone. Their growth by cell division is rapid, but the population is kept in balance by grazing species (zooplankton). DeVooys (1979) has discussed the state of the art for determining the rate of primary production of marine biomass. Recent estimates, all based on the take-up of radiocarbon, fall into the... 

The heat produced during the growth of microorganisms can be also be used for biomass concentration estimation. Different calorimetric devices (external-flow, twin-type, and heat-flux calorimeters) and different calorimetric techniques (dynamic and continuous calorimetry) have been used for on-line biomass estimation [8j. In most cases, the experimental setup is complicated and measurements are restricted to relatively small volumes (less than 1 L). Larger devices (continuous calorimeters for volumes up to 14 L) were studied by Luong and Volesky [123-125]. One of the best devices seems to be the heat-flux calorimeter developed by Marison and von Stockar. Several applications to bioprocess monitoring are given by the authors [126-129]. 

For cases where irrigation will not be used, application of fertilizer will occur once per rotation. This is envisioned to occur after harvest when the site will be most easily accessible. This design predicts the fertilizer requirement for only that portion of the plantation being harvested in a given year. Fertilizer requirements are first estimated based upon biomass growth only and then... 

One new approach to estimating biocide efficiency is to combine qualitative evaluation with the use of kinetic parameters chosen to characterize the properties of microorganisms and materials. A quantitative estimate of effectiveness is based on studies of biomass growth deceleration, with the help of rate constants for biomass growth. 

Fig. 3 Theoretical estimation of the effect of improvement of the FDCA production rate (qpDCA) on the relative glycerol consumption. The process is based on an initial biomass growth phase liom 0.5 to 16 (g CDW) 1 with a doubling time of 1 h, after which the glycerol feed is reduced to the maintenance requirement. FDCA productimi is started at 4 (g CDW) 1 and is assumed to proceed at a constant specific rate as indicated in the graphs. Calculations assume a biomass yield of 27.8 g CDW (mmol glycerol) and a maintenance requirement of 0.3 mmol glycerol (g CDW) h ...

Combining ammonium immobilization rates with estimates of C inputs and C maintenance requirement (proportional to the active microbial biomass), whose difference gave C available for microbial growth from the same experimental system (111,128), it allowed the building up of a conceptual model for C and N... 

The procedure for the estimation of qs and qp is identical to the one presented for fed-batch and continuous cultures. The only difference is in the estimation of the specific growth rate (p). Since perfusion cultures behave as batch cultures as far as the biomass is concerned, p can be obtained as described earlier for batch systems. Namely p is obtained as the slope in the plot of / Xv(t,) versus t,. 

In addition to a complete water balance, EPIC estimates plant biomass production, fertilizer use, wind and water erosion, loss of nitrogen and phosphorus from the soil, and the effect of nutrient loss from the soil on plant growth. 

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