Septic Systems– Sanitation at what cost ?

Two decades into the 21st Century, almost 2 ½ billion people around the world lack access to basic sanitation services, such as toilets or latrines. While it is unlikely that we will be able to achieve the target of the United Nations Sustainable Development Goal 6.2 (SDG6.2) in

the timeframe suggested – “By 2030, achieve access to adequate and equitable sanitation and hygiene for all“ – progress toward this target must remain a priority for our society.

However, as we try to expand access to basic sanitation, we also need to exercise care that the solutions are not contributing to collateral, unintended consequences and adversely impacting society’s progress on other important Sustainable Development Goals focused on protecting the climate through the reduction of global greenhouse gas emissions (SDG 13).

One of the simplest and most basic approaches to sanitation around the world, in both developed & developing economies, is septic treatment. With roots dating back to Mesopotamia and the Indus Valley, credit for the “modern” septic system is generally awarded to Jean-Louis Mouras who patented his concept in the late 19th Century in France. By 2015, according to UN estimates, approximately 1.5 billion people relied on septic systems for their basic sanitation. With the SDG6 targets in mind, there is a risk that due to its widespread presence that a large share of improved sanitation will be met by increased deployment of this outdated and harmful technology.

While a common criticism of septic treatment is focused on its low quality of treated effluent when compared to other decentralized wastewater solutions, we should also note that the septic system is a very basic anaerobic process where one of the primary off-gases is methane which, over the short term, is the most significant Greenhouse Gas contributor to global warming. Identifying and removing sources of methane production is rapidly gaining ground as mechanism to combat climate change due to the fact that a tonne of methane causes 86 times more warming than a tonne of CO2. In 1999, the United States Environmental Protection Agency estimated that septic systems accounted for over 10% of all methane emissions from domestic wastewater sources. If septic technology is allowed to proliferate as a result of SDG6, then we risk boosting overall methane emissions and negating the reduction steps taken in other sectors of the economy.

So, while we strive to achieve basic sanitation in developing countries and pursue rural and peri-urban development in many developed countries, we need to consider how our choice of technology may adversely affect the overall health of our planet.