Number Of Coliform Organisms At Any Particular Time Calculator

Formula Used:

\[ N_t = N_0 \times (1 + 0.23 \times C_t \times t)^{-3} \]

Number of Coliform at Initial Time (N₀):

organisms

Chlorine Residual (Cₜ):

kg/m³

Residence Time (t):

seconds

Number of Coliform at Time t (Nₜ):

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1. What is the Coliform Reduction Formula?

The coliform reduction formula estimates the number of coliform organisms remaining after a specific contact time with chlorine disinfectant. It models the disinfection efficiency in water treatment processes where chlorine is used as the primary disinfecting agent.

2. How Does the Calculator Work?

The calculator uses the coliform reduction formula:

\[ N_t = N_0 \times (1 + 0.23 \times C_t \times t)^{-3} \]

Where:

\( N_t \) — Number of coliform organisms at time t
\( N_0 \) — Number of coliform organisms at initial time
\( C_t \) — Chlorine residual concentration (kg/m³)
\( t \) — Residence time (seconds)
0.23 — Empirical coefficient
-3 — Exponential decay factor

Explanation: The formula demonstrates the exponential decay of coliform organisms when exposed to chlorine disinfectant over time, with the decay rate proportional to both chlorine concentration and contact time.

3. Importance of Coliform Reduction Calculation

Details: Accurate calculation of coliform reduction is crucial for water treatment plant design, disinfection process optimization, and ensuring compliance with water quality standards and public health regulations.

4. Using the Calculator

Tips: Enter initial coliform count, chlorine residual concentration in kg/m³, and residence time in seconds. All values must be valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What are typical values for chlorine residual in water treatment?
A: Typical chlorine residual values range from 0.2-2.0 mg/L (0.0002-0.002 kg/m³) for drinking water disinfection.

Q2: How does residence time affect coliform reduction?
A: Longer residence times with adequate chlorine residual result in greater coliform reduction due to increased contact time between disinfectant and microorganisms.

Q3: What is the significance of the -3 exponent in the formula?
A: The -3 exponent represents the empirical relationship determined from experimental data, indicating the rate of microbial inactivation under chlorine disinfection.

Q4: Are there limitations to this formula?
A: This formula assumes ideal mixing conditions and may not account for factors like water temperature, pH, or the presence of organic matter that can affect disinfection efficiency.

Q5: How accurate is this formula for different water types?
A: The formula provides reasonable estimates for clear waters but may require adjustment for waters with high turbidity or organic content that can interfere with disinfection.