| Summary: | The release of nutrients, especially nitrate from blasting operations, is a significant environmental concern
within the operation of open pit coal mines. Cost effective techniques have not yet been identified for the
removal of nitrate from large discharges such as surface coal mines. Bench scale laboratory studies for
nitrate removal from coal mine wastes have shown promising results (Norecol 1987a, 1987b). As a result
of these earlier studies, a 3 year pilot wetland study was commissioned to study plant nutrient removal
efficiency, survival, and growth relative to wastewater characteristics, and wetland maintenance
requirements. An operating coal mine on Vancouver Island in British Columbia was selected as the study
site.
This paper gives the results of the first year of operation from August to December 1988. The wetland system
removed an average of 87% of the total nitrogen over this time period. There was a slight increase in ammonia
due to productivity within the wetlands, which resulted in a net mass removal of 98.2% of NO₃-N from the
waste water. Nitrate removal rates ranged from 0.251 g/m².d in August to 0.113 g/m².d in December.
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