chapter 1 Natural Waste Treatment Systems: An Overview -- chapter 2 Planning, Feasibility Assessment, and Site Selection -- chapter 3 Basic Process Responses and Interactions -- chapter 4 Design of Wastewater Pond Systems -- chapter 5 Pond Modifications for Polishing Effluents -- chapter 6 Free Water Surface Constructed Wetlands -- chapter 7 Subsurface and Vertical Flow Constructed Wetlands -- chapter 8 Land Treatment Systems -- chapter 9 Sludge Management and Treatment -- chapter 10 On-Site Wastewater Systems.