Chapter 8: Living Machines and Solar Aquatics--Examples of Integrated, Ecological Wastewater-Treatment Systems

Chapter 8: Living Machines and Solar Aquatics: Examples of Integrated, Ecological Wastewater-Treatment Systems.

** Chapter 8 has a detailed discussion of several types of integrated ecological wastewater-treatment systems, which have incorporated many components (such as anaerobic ponds, aerobic ponds, aquaculture, constructed wetlands, algae ponds) into complete systems. Of all commercially available systems, perhaps the best known are the Living Machines and Solar Aquatics first developed by Canadian marine biologist and environmentalist Dr. John Todd. While Living Machines systems are designed to use many of the same basic wastewater-treatment processes employed in conventional facilities—such as anaerobic and aerobic microbial degradation of organic compounds, clarification, filtration, sedimentation, nitrification, denitrification, attached growth, suspended growth, and volatilization (or vaporizing and releasing of volatile organic compounds from wastewater surfaces to the atmosphere)—they can be operated without chemicals and fossil-fuel energy. Indeed, while conventional wastewater treatment is often energy- and chemical-intensive, the Living Machine systems are relatively self-sufficient and ecologically sustainable.Please refer to Chapter 8 of this book for more photographs and schematics of this type of treatment systems. You can also contact the author through for more information.

Photographs: An open, aerobic bioreactor covered with aquatic plants, in Sonoma, California, U.S.A. Bacteria and other microorganisms attach to the plants' roots and survive by breaking down organic matter in the wastewater. Natural oxygenation occurs with plant photosynthesis. The clarifier on the left is covered with water hyacinth to prevent algal growth. Clarifiers can also be covered with other types of aquatic plants, such as duckweed. Clarifiers are also called sedimentation or settling tanks, as they allow (1) natural sedimentation by gravity, which requires no chemicals and aeration (thus, no electricity is required to power mechanical aerators); and (2) plant uptake and absorption of organic nutrients and dissolved solids in wastewater so that no chemicals to settle the solids and to thicken the sludges are required. Plants growing on the water surface (in this case, common water hyacinth) shade out algae. The sludge solids are then pumped to the reed beds where they are dewatered, composted, and stored for several years. The wastewater is then piped into the ecological fluidized beds. (Photographs and copyright by Jo-Shing Yang.)