Constructed Wetlands: Periods of Technological Development
by Matthew Reusswig
I’ve been reading Wastewater Treatment in Constructed Wetlands with Horizontal Sub-Surface Flow by Jan Vymazal and Lenka Kröpfelová and their introductory chapter presents the most complete and coherent narrative of the history and development of constructed wetlands (CW) as a sanitation and waste remediation technology that I’ve seen.
One aspect of their history that I hadn’t seen elsewhere came from a table that lists 77 types of wastewater/pollution that people have attempted to treat in CW and the year in which the tests began. These 77 include phenol wastewaters (1952), photographic laboratory wastewaters (1975), cyanides and chlorophenols (1986), coke plant effluent (1998), and chlorobenzene (2004). It suggests that interest in the technology really didn’t take off until around 1980.
I’m not going to reproduce Vymazal and Kröpfelová’s table here but the difference is more apparent presented graphically anyway. I was curious what the list could say about the relative interest in constructed wetlands over time, so I took the table and plotted the total cumulative number of wastes which had been tested in CW for each year and its obvious that things took off in the late ’70’s. I also plotted the rate at which new wastes were first tested as a 5-year moving average to make the difference between the pre- and post-1980 periods pop a little more.
A Factoid Which Is Only Somewhat Related To This Post: Käthe Seidel (who conducted the first experiments on CW/macrophyte systems for wastewater treatment in 1952) wanted to call the technology the “hydrobotanical method”.