When Does It Make Sense to Put All Your Eggs in One Basket and When Does It Not: A Case Study of Biosolids Process Centralization

摘要

A growing trend for municipal utilities that own and operate multiple Water Resource Recovery Facilities (WRRFs) is to consolidate the biosolids processing facilities at one of the WRRFs. There are several advantages and disadvantages associated with centralized biosolids processing facilities. The primary advantage includes significant capital and operating cost savings that can be achieved by economies of scale. However, centralization can also bring risks and challenges. As such, the decision to centralize requires consideration of the costs, risks, site-specific conditions and owner preferences. A case study is used to illuminate these considerations. This paper presents the results of the City of Baltimore Comprehensive Biosolids Plan, which evaluated various biosolids management alternatives, including multiple centralization options. As of this writing, a final alternative has not yet been selected, but the City's project team is inclined towards a centralized facility. This paper discusses the advantages, disadvantages, risks, and costs of the biosolids management alternatives considered by the City of Baltimore. The results of this study provides insight into how to weigh cost-savings with risks and other non-economic factors associated with centralization.