Control and instrumentation issues in upgrading existing chemical feed systems in water/wastewater plants

摘要

This paper discusses control and instrumentation issues involved in upgrading existing chemical feed systems used in water/wastewater plants. The paper describes problems with the existing systems and shows how the process and control system modifications helped to improve system performance. The discussion is based on actual experience gained in implementation of two major retrofit projects, one for a polymer system in a sludge handling facility and the other for a lime system in a water treatment plant. The paper provides useful information for readers planning a chemical feed/control system upgrade project.