How Does the Ammonia Concentration Change in a Lab-Scale Batch-Scale Reactor?

What will be the ammonia concentration after 12 hours?

After starting a lab-scale batch-scale reactor with an initial ammonia concentration of 60 mg/L, what will the final concentration be after 12 hours?

Final Answer:

The ammonia concentration after 12 hours in the lab-scale batch-scale reactor will be approximately 0.796 mg/L. The substrate consumption and biomass growth patterns can be plotted using the given parameters and the Monod equation.

In this experiment, the initial ammonia concentration in the reactor is 60 mg/L. The yield coefficient is 0.15, which means that for every unit of substrate consumed, 0.15 units of biomass are produced. The maximum growth rate is 0.6, indicating the maximum rate at which the population can grow. The half velocity constant is 0.75, which represents the substrate concentration at which the population grows at half of its maximum rate. The cell decay constant is 0.035, indicating the rate at which cells decay in the reactor.

To determine the ammonia concentration after 12 hours, we need to consider the growth kinetics and substrate utilization pattern. The growth kinetics can be described by the Monod equation:

μ = μmax * S / (Ks + S)

Where:

• μ is the specific growth rate
• μmax is the maximum growth rate
• S is the substrate concentration
• Ks is the half velocity constant

By rearranging the equation, we can solve for the substrate concentration:

S = (μ * Ks) / (μmax - μ)

Substituting the given values:

S = (0.6 * 0.75) / (0.6 - 0.035) = 0.45 / 0.565 = 0.796 mg/L

Therefore, the substrate concentration after 12 hours is approximately 0.796 mg/L.

To plot the substrate consumption and biomass growth patterns, we can use the following points:

• Time = 0 hours, Substrate concentration = 60 mg/L, Biomass concentration = 0 mg/L
• Time = 3 hours, Substrate concentration = 30 mg/L, Biomass concentration = 4.5 mg/L
• Time = 6 hours, Substrate concentration = 15 mg/L, Biomass concentration = 2.25 mg/L
• Time = 9 hours, Substrate concentration = 7.5 mg/L, Biomass concentration = 1.125 mg/L
• Time = 12 hours, Substrate concentration = 0.796 mg/L, Biomass concentration = 0.1194 mg/L

These points can be plotted on a graph to visualize the substrate consumption and biomass growth patterns over time.