“Something to Digest: Recent Findings on Coating Performance in Anaerobic Digesters”

Abstract An anaerobic digester is a reactor or a process vessel in which multiple chemical and/or biochemical reactions occur simultaneously. Most municipal treatment plants utilize anaerobic treatment, which is responsible for most of the waste stabilization that happens at these facilities. Protective coatings and linings have long been utilized within these key structures to offer barrier protection for both steel and concrete substrates exposed to this service environment. Over the past few years, there has been a growing trend where publicly owned wastewater treatment plants have started accepting septage and sludge from food waste and industrial contributors very routinely. Unfortunately, many of these waste feedstocks are very volatile and can throw a properly operating digester out of balance, which in turn, can cause damage to the linings within these structures. Over the past 3-5 years, assessments have been conducted on different coating and lining types and how they have held up over time in anaerobic digesters. This paper will review the results of these assessments and will offer commentary on the pros and cons of different technologies in this severe service. Upon completion, the reader will better understand the different technologies available for anaerobic digesters and how to properly specify each type.