Cost of Being a Good Neighbor

An iteration of this abstract was accepted at the previous WEF Odors and Air Pollutants conference and was eventually presented as a video presentation. However, due to very limited audience exposure as well as the desire to include additional good neighbor 'hot button' items into the paper (permit requirement and food waste impacts), I feel that the conference audience could benefit from 're-presenting' this paper in an expanded and updated form. As population densities increase and expanding residential areas encroach closer to water resource recovery facility (WRRF) property boundaries, less tolerant communities are steadily placing more pressure on facilities to implement 'good neighbor' policies. The term 'good neighbor' can apply to multiple criteria including odors, noise, or even safety. In the context of this paper the term pertains exclusively to odor and toxic emissions control. A benchmarking study was conducted in 2016 by the Air Quality and Odor Control Committee of the Water Environment Federation (WEF). In that study, top drivers urging odor control/management decisions were identified including external customers, regulatory, and internal goals. The study found that almost 50 percent of the agencies who participated in the study implemented odor control strategies that went beyond strictly regulatory requirements. The study also quantified costs associated with odor control for conveyance system and WRRF components which included both vapor phase and liquid phase treatment. Since costs are a function of population and system scale, all costs were normalized by dividing by population served and system scale (defined as millions of gallons per day [MGD] x miles of pipeline). Both Operation and Maintenance (O&M) costs and capital costs (5-year capital improvement costs) were included. This paper focuses on five top odor performing utilities in the United States and what they spend to maintain good neighbor status. These top performers were chosen based on the following criteria: Reputation: Recognized as good neighbors by the community. Top performers don't stop at regulatory requirements for preventing nuisances. They maintain a program of continuous improvement. Diversity: All four agencies utilize unique approaches to odor control; from greater emphasis on conveyance system mitigation to greater emphasis on WRRF vapor phase systems to somewhere in the middle. This swath of approaches provides excellent comparison and allows for broader representation. Sensitivity: All four agencies are located in relatively sensitive urban locations and therefore must comply with strict regulatory as well as local requirements Costs related to odor control management for each agency were quantified and broken down into the following categories: Infrastructure capital costs (CAPEX) (based on today's dollars) for both conveyance and WRRF Direct O&M costs (OPEX) pertaining to maintenance, chemical dosing, and utility costs including electrical and water for both conveyance and WRRF Indirect OPEX Some differences between this study and the previous study include the following: OPEX in this study include indirect costs such as chemical sludge processing and hauling, chemical dosing to accommodate settling problems associated with volatile fatty acids (VFAs), additional scum pumping, and various maintenance process related maintenance activities CAPEX in this study were calculated based on existing odor control infrastructure converted to today's dollars versus 5-year capital improvement costs Cost metrics for this study were developed based on per capita (i.e.; population) and MGD versus per capita and system scale (i.e.; MGD mile) Data from the WEF study relied on numerous survey responses. This study is based on a limited number of performers and therefore takes on a more case study approach for supplementing the benchmarking study. Understanding the relative costs, cost metrics, and individual cost proportions can assist utilities in understanding where they stand and areas where there may be room for improvement or optimization. This paper discusses how the approaches of the best agency programs differ from more typical agencies as well as lessons learned from these top performers. Results of this study will prompt other agencies to ask the following key questions. How much do you spend to prevent and remedy the offsite environmental impact of your operations? Is it enough? Is the money being spent in the places where it can have the most benefit? Do you think you can do better? No two WRRFs are alike and what works for one facility might not work for another. There are differences in flow, population served, population density, climate/temperature, age and condition of infrastructure, characterization of the influent, community sensitivity, offsite odor goals, and other factors. However, there are best practices, approaches, and decisions that are common among the best performing utilities in how they minimize their off-site odor impact. This study examines holistic approaches used by top performing agencies for balancing CAPEX and OPEX for conveyance systems with those of downstream WRRFs to reduce overall odor impact. Consequences of offsite odor goal selection have a direct impact on CAPEX and OPEX related to implementation of an odor management program. More stringent odor standards result in higher present-worth costs because more stringent standards typically require larger, more expensive odor control systems that consume greater amounts of labor and energy and other consumables (e.g., chemicals, media, etc.). A representative graph of offsite odor complaints versus present-worth costs is provided in Exhibit A that shows that reducing complaints to near zero becomes exponentially more costly. Similarly, other Agency-unique and regional/localized issues can also have a direct impact on CAPEX and OPEX including permitting requirements, extent and configuration of collection system, plant processes, and high odor emitting sources including food waste receiving. Knowing where to spend odor control dollars must begin with understanding the sources of odor at a WRRF or in the conveyance network. In part, this comes from process knowledge, but measurement, monitoring, and even modeling play a critical role in informing these decisions. What may be considered 'hidden' costs are presented in this study. For example, septic plant influent can exhibit high levels of volatile fatty acids (VFAs) which can lead to problematic filamentous sludge bulking at primaries. This can in turn require additional polymer usage at downstream biosolids processes impacting costs. Certain liquid phase chemical treatment technologies can prevent septicity while others simply treat the septic sewage by removing dissolved sulfides. Understanding these hidden costs can help in implementing the best options as part of one's odor control program. A breakdown of per capita annual costs for all five agencies are provided in Exhibit B. Agency names remain anonymous while locations and specific characteristics are provided. Agencies are described as follows: PNW: Pacific Northwest agency NV: Nevada agency NoCal: Northern California agency SoCal: Southern California agency EAS: South-Eastern agency