How to Calculate Dosing Rate of Chemical in Ppm – Cost Calculator

Chemical Dosing Rate Calculator (PPM)

Water Flow Rate (m³/hr)

Desired Dosage (PPM)

Chemical Purity (%)

Specific Gravity (g/ml)

Calculation Results:

Required Dosing Rate: 0 Liters/hour

Equivalent to: 0 ml/minute

function calculateDosingRate() { var flowRate = parseFloat(document.getElementById('flowRate').value); var targetPpm = parseFloat(document.getElementById('targetPpm').value); var purity = parseFloat(document.getElementById('purity').value); var specGravity = parseFloat(document.getElementById('specGravity').value); var resultContainer = document.getElementById('resultContainer'); if (isNaN(flowRate) || isNaN(targetPpm) || isNaN(purity) || isNaN(specGravity) || purity <= 0 || specGravity <= 0) { alert("Please enter valid positive numbers for all fields."); return; } // Formula: Dosing Rate (L/hr) = (Flow Rate (m3/hr) * Target PPM) / (Purity % * Specific Gravity * 10) // 1 PPM = 1 g/m3 // Total grams needed = Flow (m3/h) * PPM (g/m3) // Available grams per liter of chemical = (Purity/100) * (Specific Gravity * 1000 g/L) // Simplified: (Q * PPM) / (Purity * SG * 10) var litersPerHour = (flowRate * targetPpm) / (purity * specGravity * 10); var mlPerMinute = (litersPerHour * 1000) / 60; document.getElementById('dosingRateResult').innerText = litersPerHour.toFixed(3); document.getElementById('mlPerMinResult').innerText = mlPerMinute.toFixed(2); resultContainer.style.display = 'block'; }

Understanding Chemical Dosing in PPM

In water treatment and industrial processes, "PPM" (Parts Per Million) is the standard unit used to measure the concentration of a chemical in a liquid. Calculating the correct dosing rate is critical to ensure safety, cost-efficiency, and effectiveness in applications like chlorination, pH adjustment, or boiler water treatment.

What is PPM?

One part per million (1 PPM) represents one part of a substance for every million parts of the solution. In water treatment, this is equivalent to 1 milligram per liter (mg/L) or 1 gram per cubic meter (g/m³).

The Chemical Dosing Formula

To determine how much liquid chemical your dosing pump needs to deliver, we use the following formula:

            Dosing Rate (L/hr) = (Flow Rate × Desired PPM) / (Purity % × Specific Gravity × 10)
        

Flow Rate: The volume of water moving through the pipe (usually m³/hr).
Desired PPM: The target concentration of the active chemical in the water.
Chemical Purity: The percentage of active ingredient in the chemical container (e.g., 12.5% for liquid bleach).
Specific Gravity: The weight of the chemical relative to water (water = 1.0).

Practical Example

Imagine you have a water system flowing at 50 m³/hr and you need to achieve a chlorine residual of 2 PPM. You are using Sodium Hypochlorite with 12% purity and a specific gravity of 1.2.

Calculation: (50 × 2) / (12 × 1.2 × 10)
100 / 144 = 0.694 Liters per hour.

Why Accuracy Matters

Under-dosing can lead to biological growth, corrosion, or failed disinfection. Conversely, over-dosing wastes expensive chemicals, can damage equipment, and may violate environmental regulations. Always calibrate your dosing pumps regularly to ensure the theoretical calculation matches the actual output.