FROM THE PREFACE In this time of dwindling budgets, increasing service needs, and increasing regulatory requirements, wastewater treatment professionals are continually called upon to upgrade their wastewater treatment plants. To do so efficiently and effectively, one must develop a clear approach to use in upgrading a plant and have the proper tools available to implement that approach. This book is meant to assist readers in developing and implementing their upgrading projects. First, Chapter 1 details the upgrading approach. The tools to be used are presented in Chapters 2 through 6. Finally, in Chapter 7, six case histories are presented to illustrate the plant upgrading techniques presented in the previous chapters. Through this book, the authors hope to assist readers in meeting their upgrade requirements, while making the most efficient use of the resources at hand.