Calculating sewage sludge production based on the population number involves estimating the amount of sewage sludge generated per person in a given area. The generation rate can vary depending on several factors, including the level of wastewater treatment, local water usage habits, and climate conditions. Here's a simplified method to calculate sewage sludge production:

Step 1: Determine the Sludge Generation Factor (SGF)

The Sludge Generation Factor (SGF) represents the amount of sewage sludge produced per capita. It is typically expressed in terms of kilograms of dry solids per person per year (kg/person/year). The SGF can vary, but a commonly used value is around 0.02 kg/person/year for areas with primary wastewater treatment and 0.04 kg/person/year for areas with secondary wastewater treatment.

Step 2: Gather Population Data

Obtain the population data for the area you're interested in. This could be a city, town, municipality, or any other geographical area for which you want to estimate sewage sludge production. You'll need to know the total population for a specific time period, typically a year.

Step 3: Calculate Sewage Sludge Production

Use the following formula to calculate sewage sludge production:

Sewage Sludge Production (in kg/year) = Population × SGF

Where:

• Population is the total population of the area.
• SGF is the Sludge Generation Factor (kg/person/year).

Step 4: Convert to Desired Units

The result will be in kilograms per year. If you need the value in other units (e.g., tons per year or metric tons per year), you can convert it accordingly. Remember that 1 ton = 1,000 kilograms.

Here's an example calculation:

Suppose you want to estimate sewage sludge production for a city with a population of 100,000 people, and it has secondary wastewater treatment:

SGF = 0.04 kg/person/year Population = 100,000 people

Sewage Sludge Production = 100,000 people × 0.04 kg/person/year = 4,000 kg/year

To convert to metric tons:

Sewage Sludge Production = 4,000 kg/year ÷ 1,000 = 4 metric tons/year

So, in this example, the estimated sewage sludge production for the city with a population of 100,000 people is 4 metric tons per year.

Keep in mind that this is a simplified calculation, and actual sewage sludge production can vary depending on factors like wastewater treatment processes, industrial contributions, and water consumption habits. For more accurate estimates, you may need to consult local wastewater treatment data or conduct specific studies in the area of interest.

Narendra Kumar Maurya , I agree with the method you describe, but your numbers seems very low. It should be something in the order of “.. 35 to 85 g dry solids per population equivalent per day (gTS PE-1 d-1).” https://www.iwapublishing.com/news/sludge-production

I agree with Henrik Rasmus Andersen the approach above from Narendra Kumar Maurya sounds ok, but has gotten seriously off someplace.

From a theoretical point, the loading of the WWTP with BOD (Catchment characeristic) is the critical parameter, together with the relative sludge yield (characteristic of the sludge reactor) You will get the sludge production. You can run sludge reactors as mineralising reactors (very high hydraulic retention times, i.e. 30 h: usually only used for very small plants in which You do not want to tackle the sludge). Or You can optimise the reactor for maximum sludge output (because You want to use the sludge in biogas producing digestors).

From a practitioners view about 2 g/L primary sludge and 2 g/L excess sludge seems realistic for normal european WWTPs (this would agree to @Henriks numbers