Robert H. Kadlec 1
The intentional use of natural and constructed wetlands to remove nutrients from both point and non-point sources of water is a rapidly growing technology, having expanded from zero to hundreds of systems in just over two decades in North America. This treatment technology can add aesthetic and habitat values to the regional landscape. Large amounts of research and operating data are now available, which support an expanding set of design and analysis tools. This paper reviews and summarizes the available data, assembled over the past three years as part of USEPA and other data collection projects. A concise representation of the experience base is presented, which utilizes mass balances and calibrated removal models. These deterministic equations apply to mature systems, and to average performance over periods of months to years. On a shorter time scale, stochastic phenomena produce fluctuations in wetland parameters. The economic experience is very good for operating costs, and competitive in terms of capital. Applications to the treatment of agricultural runoff are presented, including the Everglades protection wetlands.
