Although initially based purely on environmental principles of reuse and recycling, natural waste treatment systems proved to have economic advantages over mechanical systems in many cases, being less expensive to build and operate as well as requiring less energy. Thus, natural waste treatment methods re-emerged even as advanced wastewater treatment technologies exploded in growth. Reflecting this burgeoning popularity, "Natural Wastewater Treatment Systems" is the first book to integrate all the major types of natural treatment systems into a single source. Beginning with an overview of the types of natural treatment systems, the book outlines the planning, feasibility assessment, and site selection processes unique to natural processes as well as the basic process responses and interactions governing natural systems. The authors then examine the systems in detail, discussing wastewater pond systems, free water surface constructed wetlands, subsurface and vertical flow constructed wetlands, land treatment, sludge management, and onsite wastewater systems. They illustrate the practical aspects through 30 examples; include 178 data tables for comparing costs, performance, and constraints; and describe new approaches to partially mixed ponds, including dual-powered aeration ponds. Written by eminent experts in natural waste treatment, "Natural Wastewater Treatment Systems" is an invaluable tool for selecting, planning, and implementing ecologically and economically sound wastewater treatment systems.