The immense environmental challenges facing the world now and in years to come can only be met through marshalling the talents of the best environmental engineers and scientists, and through the use of innovative, cost-effective solutions. Written by three leading aeration experts, Aeration: Principles and Practice, covers the principles and practice of aeration, a unit process critical to the performance of activated sludge treatment and to the budget of wastewater plants.

This reference presents the state of the art in aeration, using examples from a variety of facilities in the USA and Europe. The authors investigate conventional and deep-tank aeration systems for BOD removal and nitrification, as well as high-purity oxygen systems. Operating and capital costs, as well as energy use data are presented together with design information allowing the adaptation of new aeration technologies to plants of diverse size.

Both practitioners and advanced students of wastewater management will appreciate the detailed presentation of oxygen transfer principles, especially as they are illustrated in numerous applications. With the information presented in this book engineers and managers will be able to understand and monitor the efficiency of existing aeration systems and to develop strategies for process improvement.

Antislavery and Abolition in Philadelphia considers the cultural, political, and religious contexts shaping the long struggle against racial injustice in one of early America's most important cities. Comprised of nine scholarly essays by a distinguished group of historians, the volume recounts the antislavery movement in Philadelphia from its marginalized status during the colonial era to its rise during the Civil War.

Philadelphia was the home to the Society of Friends, which offered the first public attack on slavery in the 1680s; the Pennsylvania Abolition Society, the western world's first antislavery group; and to generations of abolitionists who organized some of early America's most important civil rights groups.

These abolitionists -- black, white, religious, secular, male, female -- grappled with the meaning of black freedom earlier and more consistently than anyone else in early American culture. Cutting-edge academic views illustrate Philadelphia's antislavery movement, how it survived societal opposition, and how it remained vital to evolving notions of racial justice.