A Greenhouse Gas Inventory of a Conventional Water Treatment Plant
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|Title||A Greenhouse Gas Inventory of a Conventional Water Treatment Plant|
|Other Date||24-May-2011 (iso8601)|
|Note||Presented at The Oregon Water Conference, May 24-25, 2011, Corvallis, OR.|
|Abstract||The Joint Water Commission (JWC) in Forest Grove, Oregon completed a greenhouse gas (GHG) inventory of all the direct and indirect emissions associated with the daily operations of its 75 MGD conventional water treatment plant. Currently, very few water and wastewater facilities have completed a greenhouse gas inventory to date.
This analysis uses a variety of data sources and public-domain tools for emissions factors and calculation methods. Embodied emissions in purchased goods and services were calculated using dollar values spent and emissions factors based on averages for the U.S. economy. Emissions related to electricity consumption include analysis of utility specific, regional, and national electricity emissions factors. Emissions from disposal of solid waste are based on the weight and general type of the waste, and the operations of the receiving facility.
In 2007, the JWC’s total emissions were 21,440 metric tons of carbon dioxide equivalent (MT CO2e), roughly equal to the annual emissions of 4,099 passenger vehicles. Yearly variations (2007-2009) in emissions were very low and were due to construction projects. The JWC’s largest GHG emissions source was the consumption of electricity (81% on average) and the embodied emissions within purchased water treatment chemicals (13% on average).
One climate change risk facing utilities is financial. If a “cost of carbon” (at levels currently anticipated) were passed along to JWC through its purchases of energy, goods, and services, the organization could pay an additional $313,000 each year. Reducing this financial risk can be accomplished by reducing purchases of high emission intensity goods, namely electricity and treatment chemicals. Limiting emissions due to electricity consumption can be done by replacing older equipment with high-efficiency equipment or utilizing electricity from less carbon intensive sources, such as creating renewable solar and micro-hydro energy on site.