Wastewater Emissions - An Overlooked Source?

by cstew92 on November 28, 2016 - 4:26pm

The purpose of this article is to reveal a discrepancy in the the estimates put forth by the International Panel on Climate Change (IPCC) regarding global wastewater fossil carbon in their total greenhouse gas emissions. According to the IPCC their model when considering wastewater emissions relies on assuming that the carbon contained and released from wastewater is non-petroleum based – for example human waste. However, studies have shown that petroleum based products like detergents, and other household products have been found to leach harmful petrochemicals into the wastewater system, which eventually add to total greenhouse gas emissions.

As a result, researches from Colgate University and the University of California, Irvine have teamed up to conduct experiments investigating fossil-related carbon emissions from wastewater treatment facilities at various points in the treatment process on a municipal and industrial scale. Their findings suggest an increase of 12% to 23% in greenhouse gas emissions from wastewater in relation to initial estimates that only involve methane and nitrous oxide. The article provides a solution to this problem with emphasis on the idea of on-site carbon sequestration to help reduce the impact of wastewater treatment facilities.

As the son of a wastewater treatment operator this article really intrigued me on a personal level. The management of one of our most precious, yet abundant natural resources requires many factors to be accounted for. Some of which we do not yet have the practical or technical capabilities of understanding. Due to the vast abundance of water throughout our planet, management of this resource often poses uncertainty and in some cases – like the IPCC’s report, important factors are often overlooked. Freshwater is known as a renewable (flow) resource in that there is a large enough supply simultaneously entering and exiting the system that is sustainable for current human consumption. However, when thinking about water we sometimes disregard the fact that like all renewable resources, there is a threshold to which water can be sustainably consumed. This is known as the critical zone where extraction rates cannot exceed the rate of replenishment. If this occurs, freshwater could become a stock resource where it would only be available in limited supply.

In the case of the IPCC, omitting wastewater emissions data from their total emissions estimates reflects a level of ignorance due in large part to the fact that those in control used assumptions when considering the role of wastewater in greenhouse gas emissions. A level of uncertainty will always be present in any form of resource management; however, decisions still need to be made. The decision made by the IPCC to omit vital information regarding wastewater emissions demonstrates the ecological and scientific uncertainty that still remains in resource management. Also, this situation helps to demonstrate the power that the state has within resource management by allowing the omission of information to occur. It makes you wonder can inconsistencies like the one illustrated here be occurring in other cases involving environmental monitoring? As scientific research continues to be done, one may begin to question the integrity of those in power that maintain control and distribution of the information.


American Chemical Society. (2016, November 2). Wastewater treatment plants: An overlooked source of carbon emissions. ScienceDaily. Retrieved November 23, 2016 from www.sciencedaily.com/releases/2016/11/161102085229.htm




Dear Author,
I'd like begin by saying that this article is very informative and incorporates the definition of renewable resources in a great way for the reader to understand the significance of exceeding the threshold and potentially relegating renewable resources to stock resources. I'd also like to point out that by incorporating a personal touch, "the son of a wastewater treatment operator" you convey the blog with a sense of confidence to the reader that you have enough knowledge to understand the impacts that wastewater emission have. On the other hand you only mention that the IPCC omitted the emission caused by wastewater, is there a specific reason? You suggest they "used assumptions" when omitting these datum from emission reports, as a reader I don't know what "assumptions" they are using to neglect this information.
Below I have provided a link that briefly describes reasons why data are omitted in some cases.
Overall it was a fantastic blog and I really enjoy the personal touch that you added to it!

Thank you for your feedback. For some reason I am unable to access the website you've provided. With regards to your question about the assumption made by the IPCC, if you re-read the first paragraph it might make it a bit more clear as to why the IPCC chose to omit emissions caused by wastewater. As you may know, The IPCC is in charge of providing various kinds of scientific data to decision makers and so when they produce estimates of global greenhouse gas emissions - things like fossil fuel combustion, deforestation, and other industrial and agricultural activities are included. However, the study in which this article relates to determined that the IPCC completely ignored the thought of CO2 emissions from wastewater treatment facilities because they assumed that any carbon released was due to biological processes (like human waste) which is carbon neutral. The problem with this is that household items like detergents, soaps, etc., contain specific chemicals that when processed during treatment are not always contained 100%. Therefore, this study suggests the IPCC neglected to account for nearly 23% of total greenhouse gas emissions in their estimates. As you can see this poses huge implications for decisions going forward, and also raises doubt as to whether or not those who are in charge of data collection are capable of this position.

Here is a copy to another article I found that discusses the same study and might provide more information for you.



I was drawn to your post because this is a topic i'm not very familiar with. I never really considered that greenhouse gas emissions could come from wastewater. You delivered the information with extreme clarity and really demonstrated that you are very knowledgeable on this topic. I liked how you highlighted the fact that this is a good example of uncertainty in resource management. Managing the human impacts on natural resources is extremely difficult, but like you said, decisions need to be made anyway.

It is concerning that the IPCC, a panel tasked with documenting causes of climate change, would omit such a large factor of greenhouse gas emissions from wastewater. Whether it was intentional or unintentional, it raises concerns about who is in charge of this huge responsibility. This definitely emphasizes that more regulation is needed when it comes to precious resources such as water. If we wish to truly combat climate change, it's crucial that we have a thorough understanding of the impacts of our actions.