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By Tom Johnson, CH2M HILL Water/Wastewater Technologist, and Robert Forbes, CH2M HILL Eastern US Residuals Technology Leader

Tom Johnson and Robert (Bob) Forbes will be presenting at the Water Environment Federation (WEF) Energy and Water Conference 2011. To hear more about “WERF’s Comprehensive Energy Analysis and Tools for WWTPs (CHEApet) Undergoes Testing and Enhancements for Holistic Assessments of Energy and Carbon Footprints,” developed by Johnson, Forbes, George Crawford, and Lauren Fillmore, check out their presentation Tuesday, August 2 at 10:45 am as part of Session 9. Learn more about all of the CH2M HILL WEF Energy and Water 2011 presentations.

CHEApet is a Carbon Heat Energy Analysis Evaluation tool that was created by the Water Environment Research Federation (WERF) with CH2M HILL’s Tom Johnson as its primary developer. This tool was created when there became a need for a modeling tool that could quantify and manage energy consumption and renewable energy production for utilities. CHEApet was developed under WERF’s Optimization Challenge to model energy consumption and production as well as part of the overall performance of wastewater treatment plants (WWTPs).

CHEApet is designed to help guide a utility toward sustainability of its wastewater treatment and reclamation functions. The tool was constructed to allow a facility to explore energy efficiency optimizations as well as carbon footprint estimates while comparing the results to existing conditions. Enhancements to CHEApet are being made based on beta-testing CHEApet at three selected WWTPs across the U.S., as well as linking CHEApet to related tools such as WERF’s Life Cycle Assessment for Energy Recovery (LCAMER) and the Biosolids Emissions Assessment Model (BEAM). 

The CHEApet tool is a holistic model that can also be used to evaluate detailed features of wastewater treatment, such as the treatment of high-strength recycle streams within the WWTP. Another feature of the tool is that it looks at additional carbon sources and offsets of biosolids processing and beneficial uses. It also considers plant specific emissions and credits related to use of power from offsite sources and onsite power generation.

Energy consumption, chemical use, treatment process emissions, and biosolids management options all contribute to a facility’s carbon footprint. Use of CHEApet can establish the baseline of a WWTP’s carbon footprint by which to measure future improvements as well as alternatives being considered. The results will allow users to identify and exploit opportunities for energy and resource recovery, which will save costs and reduce the carbon footprint of wastewater treatment and biosolids management.

As of mid-2011, CHEApet has been demonstrated at three WWTP beta test sites where baseline CHEApet scenarios were developed for each of the WWTPs and their products. Emissions estimates from plant processes and offsets for carbon sequestration via beneficial uses of biosolids were included in the baseline scenarios. Workshops and webinars were held with the beta-test participants to present the baseline scenarios and identify projects they are considering for energy optimization, resource recovery, and carbon-footprint reduction.  Our WEF Energy and Water 2011 presentation will discuss results of this testing and how they may be applied to the energy and carbon footprints of other WWTP sites.  WERF will soon make CHEApet available to its subscribers for additional testing and applications.

Tom Johnson is a Water/Wastewater Technologist in the CH2M HILL Charlotte, NC, office. He has project experience in wastewater process analysis, modeling, water/wastewater process design, wastewater collection and conveyance, and water distribution. His specialty is wastewater process, optimization, sustainability and energy efficiency. Mr. Johnson was recently selected by the WEF Board of Trustees as the 2011 recipient of the Outstanding Young Water Environment Professional Award for his demonstrated contributions to enhancing the activities of WEF, contributions to WEF Member Associations and to WEF Committees and improvement in the fundamental knowledge of performance of wastewater collection and treatment systems, water resource protection and research on issues important to the water environment.

Robert Forbes is CH2M HILL’s Eastern US Residuals Technology Leader with over 30 years of diverse experience in the planning, design, and construction of water and wastewater treatment systems and facilities.  He is a specialist and firm-wide resource in the treatment and management of residuals and biosolids from water and wastewater treatment processes. He also provides expertise in biosolids master planning, permit assistance, grant applications,  , design reviews, value engineering, and the application of odor control technologies to biosolids and wastewater collection/treatment systems.