APPLICATIONS GUIDANCE FOR PARTICLE COUNTING  TECHNOLOGY AT DRINKING WATER UTILITIES   The motivation for this book was to provide background information on the technology used to measure particles in water and provide answers to the most commonly asked questions about particle counting technology and its application. The goal of this project was to combine information on particle counting gathered from many sources and to provide a comprehensive reference text covering all aspects of particle counting in drinking water treatment. This book is a compilation of the experience of many drinking water utilities using particle counting to help them optimize their day-to-day operations. Particle counters are also being used extensively in hydraulics and pharmaceutical industries as well as marine sciences. This book draws upon the substantial experience of these industries to advance the state of particle counting applications in drinking water treatment.   The contents of this manual include: An introduction to the technology and nature of particulates in water Calibration of particle counters and calibration materials Instrument purchasing specifications Applications and installation guidelines Data collection strategies and data interpretation Performance verification methods and their use in drinking water treatment plants Key elements of a routine maintenance program and basic troubleshooting Detailed Standard Operating Procedures for particle counter performance assessment   Each chapter begins with an overview section, outlining the key information contained in that chapter. This overview at the beginning of each chapter, along with the chapter road-map described in Chapter 1 are meant to assist readers find the information they are looking for. Many utilities are considering purchasing particle counters and others who already have the instruments installed are seeking guidance to help them maximize the usefulness of this technology. Utilities who have not used particle counting before may not be prepared for the level of technical resources required to properly maintain these instruments in the long-term. Treatment plant personnel struggling with the development of a purchasing specification or with decisions on sampling locations and frequencies will find simple solutions to common problems. Tips on how to avoid common installation-related (e.g., electrical, water or data retrieval) pitfalls are provided. The state of the art for communications options to SCADA systems or stand alone computers are described in detail. Appendix A includes detailed methods for instrument setup and performance validation. These methods have been written in a Standard Operating Procedure-type style to assist operators and technical personnel using these instruments on a day-to-day basis. The water utilities whose experience helped shaped this book represent a wide range of background knowledge in particle counting, different goals, and widely differing resources. It is hoped that the information presented here will aid utilities to overcome hurdles and unexpected difficulties which others have already successfully conquered.