Using constructed wetlands to treat biochemical oxygen demand and ammonia associated with a refinery effluent.
This study evaluated the effectiveness of constructed wetlands for tertiary treatment of a petroleum refinery effluent. Specific performance objectives were to decrease 5-day biochemical oxygen demand (BOD(5)) and ammonia by at least 50% and to reduce toxicity associated with this effluent. Two bench-scale wetlands (replicates) were constructed in a greenhouse to provide tertiary treatment of effluent samples shipped from the refinery to the study site. Integrated wetland features included Typha latifolia Linnaeus planted in low organic (0.2%), sandy sediment, 48-h nominal hydraulic retention time, and 15-cm overlying water depth. Targeted constituents and aqueous toxicity were monitored in wetland inflows and outflows for 3 months. Following a 2 to 3-week stabilization period, effective and consistent removal of BOD(5) and ammonia (as NH(3)-N) from the effluent was observed. Average BOD(5) removal was 80%, while NH(3)-N decreased by an average of 95%. Survival of Pimephales promelas Rafinesque and Ceriodaphnia dubia Richard (7-day, static, renewal exposures) increased by more than 50% and 20%, respectively. Reproduction of C. dubia increased from zero in undiluted wetland inflow to 50% of controls in undiluted wetland outflow. This study demonstrated the potential for constructed wetlands to decrease BOD(5), ammonia, and toxicity in this refinery effluent.
Huddleston
G M
GM
Clemson Institute of Environmental Toxicology, Clemson University, 509 Westinghouse Road, Pendleton, South Carolina, 29670, USA.
Gillespie
W B
WB
Rodgers
J H
JH
D000641:Ammonia / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D007220:Industrial Waste; D010100:Oxygen / Q000378:metabolism*; D010578:Petroleum; D010944:Plants / Q000187:drug effects*; D013997:Time Factors
D007220:Industrial Waste; D010578:Petroleum; D000641:Ammonia; D010100:Oxygen