The Climate Driven World and Wastewater Treatment

Greenhouse gas production during wastewater treatment

 by Wendy Wert
Sewer Leaks editor

On February 28, 2008 the Los Angeles Basin Section (LABS) of California Water Environment Association (CWEA) hosted a training event titled “Wastewater Treatment in Tomorrow’s Climate Driven World: The California Perspective”. The session was held in Encino, CA.

The featured speaker for the evenings training event was Brian Whitaker of CH2M HILL. Concerns over climate change as a consequent of the release of greenhouse gases (GHGs) has resulted in a range of efforts to regulate and reduce their emissions as well as to replenish the stores of fixed carbon (C) on earth.

Mr. Whitaker began the discussion by introducing the California Global Warming Solutions Act of 2006 (AB 32). The goal of AB 32 is to achieve reductions in statewide GHG emissions to the levels in 1990, by the year 2020.

The California Air Resources Board (CARB) is tasked with adopting regulations to achieve this lofty objective. As a consequence the implementation timeline has been fast-tracked. The key date for the regulated community is January 2010, which is the adoption date for enforceable regulations for early action measures. The concern is that due to this accelerated scheduled it will be difficult to ensure that scientifically valid, measurable and repeatable procedures will be relied on to set emission criteria and compliance limits.

Mr. Whitaker encouraged stakeholder involvement in the on-going scoping plan development process. On April 4, 2008 there will be a scenario workshop to explore different emission reductions strategies. The adoption deadline for the scoping plan is January 1, 2009. The initial phase of mandatory reporting is scheduled to begin in 2009. The initial sources to be
covered of interest to the wastewater sector are electric generating facilities, cogeneration facilities, and stationary combustion.

The Intergovernmental Panel for Climate Change (IPCC) and EPA are establishing protocols for GHG emissions determination. The compounds of concern are methane and nitrous oxide because they are anthropogenic. Sewer sector source categories are being set. Methane emission potential is a factor of BOD loading and nitrous oxide emission potential is a factor of total nitrogen loading. GHG emissions are of concern since the US is the world’s second largest discharger and if California were to report separately from the rest of the nation, it
would be the 10th highest GHG discharger globally.

California is a significant contributor of GHGs. As a result of AB 32 Climate change action is on a fast track and potentially outpacing science. As shown in the above figure, emission standards for multiple segments of a typical treatment train are currently being developed, therefore it is recommended that POTWs engage in the process. In addition, the profession is
encouraged to work together to present consistent recommendations based on sound science, employ strategies the lead to our primary goal of comprehensive water resource protection, and remain proactive to solicit credits for early actions.

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