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Influent Wastewater Characteristics

Updated: Oct 12, 2023

This post will provide data/tables to give you a starting point when it comes to evaluating influent wastewater characteristics in the absence of plant-specific data. In my own work I make reference to the textbook data tables shown below to compare data I generate in-the-field to "expected" or "typical" data.

Influent Wastewater
Influent Wastewater

As a specific example of how I use the textbook influent wastewater tables, I was at a beautiful municipal wastewater plant in the southwest US, where I generated the following data, tabulated below, from my field testing. The influent to the bioreactor had what I immediately thought were really high orthophosphate numbers, bolded in red. The first thing I did was compare the values I measured at this plant with textbook values and saw that this plant had an influent phosphate concentration more than twice as high as would be expected. This is not a problem, necessarily, but it requires that I obtain a better understanding of the influent sources to this municipal wastewater plant. Fortunately for me, I had access to staff at the plant who were extremely knowledgeable and patient, answering all of my many questions.

The cells in the table below, filled with the color blue, are calculation cells. I do this for my own reference in all of my spreadsheets. The cell filled in with the reddish-brown color is my way of indicating an error in the lab work I did. In another post I'll use this table to discuss the constant problems I have when trying to do a nitrogen balance. For all of my field testing I use Hach's TNT (test-in-a-tube) reagents which makes field work so, so much easier to do. But of all the TNT tests I perform the one test I always have trouble with is the total Kjeldahl nitrogen (TKN) test.

Table showing data I generated in-the-field.
Municipal Plant Field Data

A simple process flow diagram for this municipal plant is shown below. This is an MLE (Modified Ludzack Ettinger Nitrogen Removal Process) bioreactor followed by an MBR (membrane bioreactor) where the permeate is reused for a variety of purposes.

Simple wastewater process flow diagram.
MLE Bioreactor + MBR

In the photo below you can see a membrane module that was pulled out for inspection while I was onsite. My particular interest in this activity was to collect sludge from the membrane strands (noodles) so that I could analyze the iron concentration in the sludge.

Submerged membrane bioreactor module being pulled for cleaning.
Membrane Bioreactor Module


The table below lists influent data for BOD, nitrogen, and phosphorus, three key parameters that I'm always interested in and that I often measure when I'm at a wastewater treatment plant. To be clear though, I measure COD in place of BOD because the COD measurement is a two-hour test easily performed in-the-field. This table lists data specific to municipal plants.

Data table listing influent concentrations for BOD, nitrogen, and phosphours.
Henze, et. al. Select Influent Wastewater Characteristics

If you want a single-page PDF of the table above from Henze, et. al., you can download the file below.

Download • 132KB


The table below lists influent data for a range of parameters. This table also lists data specific to municipal plants.

Detailed table listing a wide range of influent wastewater concentrations.
Metcalf & Eddy Influent Wastewater Characteristics

If you want a single-page PDF of the table above from Metcalf & Eddy, you can download the file below.

Download • 106KB


I do a lot of work in industrial plants, particularly in petrochemical plants. The table below is specific to refinery influent wastewater.

Data table listing influent wastewater concentrations specific to refineries.
American Petroleum Institute Influent Wastewater Characteristics

If you want a single-page PDF of the table above from the American Petroleum Institute, you can download the file below.

Download • 103KB


1 Comment

Nov 28, 2023

Understanding the water characteristics is most important to build the waste water treatment plants that purifies the water well. This article provides a lot of valuable insights.

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