This research takes the liberty to assign the role of wastewater agencies as stewards of the environment and public trust. This is a different philosophy than seen at most utilities: comply with the regulations for the lowest possible sewer user costs. In this new, enlightened role, wastewater agencies need to consider the full range of benefits and costs associated with their activities including the impact on the broader community.
There are many case studies that prove the broader community must be considered in order for an alternative to be sustainable. The City of Diluth, for example, abandoned incineration and built anaerobic digesters so they could recycle Class B biosolids to local farmland. It seemed like a win-win situation in which the broader community, agriculture specifically, would benefit from free fertilizer. However, the broader community perceived risks to human health and the environment that they were not willing to accept. As a result, the City was forced to re-evaluate alternatives which included the views and opinions of all affected parties.
WERF will soon be publishing a report to help utilities with Biosolids management planning titled "An Economic Framework for Evaluating the Benefits and Costs of Biosolids Management Options." The intent of this research report is to help wastewater agencies and stakeholders understand the benefits and costs of various biosolids management options. The report describes the approaches, methods, and tools available to help utilities take a broad perspective and develop benefit-cost analysis (BCA) of their biosolids management options.
Wastewater agencies, regulatory bodies, the research community, and other entities have identified and implemented a suite of practices, processes, and regulations that enable the safe and prudent management of biosolids. Still, wastewater agencies face challenges as they consider how to best manage biosolids including:
- Biosolids management options tend to require high capital outlays and operating expenses
- Many biosolids management options tend to be controversial due to public concern over various real or perceived risks and inconveniences
Technological advances are making several new processes and options available, or more economically attractive, than in the past. New technological advances:
- Provide processes that improve energy efficiency
- Provide ways to generate energy or other useful value-added products from biosolids
- Reduce greenhouse gas emissions associated with global climate change concerns
Although BCA is a valuable tool, it is important to acknowledge its limitations. BCA is one of several tools that wastewater agency managers and public officials need to have in their decision support toolbox to effectively deliberate biosolids management options and decisions.
The types and levels of benefits and costs associated with a specific biosolids management option are highly utility-, locations-, and option-specific. The benefits of the use or disposal of biosolids may include:
- Reduced traditional energy consumption and air pollution, where biosolids provide renewable biofuels, thermal values, and/or reduced energy costs.
- Improved sustainability and reliability of a biosolids program, by providing the community with a more diversified and viable long-term set of options for addressing their biosolids needs
- Reduced odor-related issues and concerns, by pursuing options that help control odor and address concerns from neighbors
- Increased land productivity and/or restoration through soil enhancement from land application practices
On the cost side of the ledger, there are two types of issues that utilities may need to address:
- High direct financial cost of biosolids management options, including the lifecycle costs and operation and maintenance costs of all capital equipment, over the useful economic life of the investment
- Perceived adverse environmental and public health impacts, nuisance and aesthetic concerns
The report provides a straightforward, systematic framework for how to conduct a BCA or economic evaluation. Some of the key steps identifiedin the report include:
- Defining a suitable baseline, this is the simplest alternative that is easily defined
- Including impacts that are important, even if they cannot be readily quantified or monetized, so that these important benefits and costs are suitably identified
- Recognizing and acknowledging uncertainties and omissions, and considering how these may impact the net benefit results using tools such as sensitivity analyses
- Including stakeholder involvement at all stages of the process
- Promoting transparency and communication throughout the process, to enable replication and foster trust in the outcomes
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