Over the last year HMVT has tested the
possibilities of using a constructed wetland type treatment for the treatment
of groundwater contaminated with chlorinated solvents and chlorobenzenes. For
the test we used our specially designed constructed wetland pilot test container.
The equipment in this container allows for testing on site, using various constructed
wetland types. With the equipment we can test various flow patterns in the
wetland, various types of soil matrix of the wetland and various plant types.
Looking into the results, after 5 months of stabilization PCE,TCE, DCE and VC were fully degraded from influent to effluent (>99%). Interestingly, despite lack of aerobic conditions measured in the waterflow, aerobically active microbes were abundantly present (DNA detection), and aerobically degradable contaminants were metabolized. This likely was a result from activity surrounding the plant roots, creating aerobic niches within the soil matrix. Chlorobenzenes were also fully degraded (100%). Effluent values were well below discharge limits.
Conducting the test has significantly reduced any uncertainties on the potential of a constructed wetland for the treatment of the contaminated groundwater on the site.. With the results of the tests, we have now a complete set of data to design a full scale constructed wetland, which appears to be very feasible for the site in question.
More information: constructed wetlands (HMVT)