scholarly journals Effectiveness of a Constructed Wetland with Carbon Filtration in Reducing Pesticides Associated with Agricultural Runoff

Author(s):  
Laura B. McCalla ◽  
Bryn M. Phillips ◽  
Brian S. Anderson ◽  
Jennifer P. Voorhees ◽  
Katie Siegler ◽  
...  

AbstractThe Salinas Valley in Monterey County, California, USA, is a highly productive agricultural region. Irrigation runoff containing pesticides at concentrations toxic to aquatic organisms poses a threat to aquatic ecosystems within local watersheds. This study monitored the effectiveness of a constructed wetland treatment system with a granulated activated carbon (GAC) filter installation at reducing pesticide concentrations and associated toxicity to Ceriodaphnia dubia, Hyalella azteca, and Chironomus dilutus. The wetland was supplied with water pumped from an impaired agricultural and urban drainage. Across five monitoring trials, the integrated system’s average pesticide concentration reduction was 52%. The wetland channel and GAC filtration components individually provided significant treatment, and within each, pesticide solubility had a significant effect on changes in pesticide concentrations. The integrated treatment system also reduced nitrate by 61%, phosphate by 73%, and turbidity by 90%. Input water was significantly toxic to C. dubia and H. azteca in the first trial. Toxicity to C. dubia persisted throughout the system, whereas toxicity to H. azteca was removed by the channel, but there was residual toxicity post-GAC. The final trial had significant input toxicity to H. azteca and C. dilutus. The channel reduced toxicity to H. azteca and removed toxicity to C. dilutus. GAC filtration reduced H. azteca toxicity to an insignificant level. There was no input toxicity in the other three trials. The results demonstrate that a wetland treatment system coupled with GAC filtration can reduce pesticide concentrations, nutrients, suspended particles, and aquatic toxicity associated with agricultural runoff.

2007 ◽  
Vol 205 (3-4) ◽  
pp. 355-364 ◽  
Author(s):  
Volodymyr Tomenko ◽  
Sirajuddin Ahmed ◽  
Viktor Popov

Environments ◽  
2020 ◽  
Vol 7 (10) ◽  
pp. 89
Author(s):  
Chukwuemeka Ajaero ◽  
Ian Vander Meulen ◽  
Monique C. Simair ◽  
Mignon le Roux ◽  
Joanne Parrott ◽  
...  

The reclamation of oil sands process-affected water (OSPW) is a matter of environmental importance because of the aquatic toxicity to biota. This study describes refinements in advanced analytical methods to assess the performance of biological treatment systems for OSPW, such as constructed wetland treatment systems (CWTSs). Assessment of treatment efficiency by measurement of the degradation of naphthenic acid fraction compounds (NAFCs) in OSPW is challenging in CWTS due to potentially interfering constituents such as humic acids, organic acids, salts, and hydrocarbons. Here we have applied a previous weak anion exchange (WAX) solid-phase extraction (SPE) method and high-resolution Orbitrap-mass spectrometry (MS) to remove major interferences from the NAFC analysis. The refinements in data processing employing principal component analysis (PCA) indicates that the relative abundance of NAFCs decreased with time in the treated OSPW relative to the untreated OSPW. The most saturated NAFCs with higher carbon numbers were relatively more degraded as compared to unsaturated NAFCs. The use of Kendrick plots and van Krevelen plots for assessment of the performance of the CWTS is shown to be well-suited to detailed monitoring of the complex composition of NAFCs as a function of degradation. The developments and application of analytical methods such as the WAX SPE method and high-resolution Orbitrap-MS are demonstrated as tools enabling the advancement of CWTS design and optimization, enabling passive or semi-passive water treatment systems to be a viable opportunity for OSPW treatment.


2009 ◽  
Vol 60 (2) ◽  
pp. 301-309 ◽  
Author(s):  
P. G. Sonavane ◽  
G. R. Munavalli

A constructed wetland treatment system (CWTS) has been adopted for removal of nitrogen from wastewater. The design methodologies developed for CWTS in previous studies were based on thumb rules, and first order/Monod type kinetics models. The use of kinetic models is system/environment specific. There is scope to assess the potential of other reaction kinetic models for their usefulness and applicability. In the present study, lumped and distributed parameter models incorporated with various reactions kinetic were developed. The various processes were incorporated in distributed parameter model for nitrogen transformations. Laboratory/pilot-scale field experiments were carried out and used for verification and application of models developed. The reaction rate parameters were estimated using non-linear least square analysis. The results showed that the conditions within CWTS can be simulated by plug flow. The plant uptake rate was found to be higher than denitrification for nitrate removal. Nitrification and plant uptake are equally dominant for the removal of ammonia nitrogen. The relative contributions by various processes for nitrogen removal can be established using the distributed parameter model. The developed simulation model can be used as a CWTS planning and design tool for the effective control and treatment of nitrogen induced pollution.


2001 ◽  
Vol 44 (11-12) ◽  
pp. 435-440 ◽  
Author(s):  
J.A. Jackson ◽  
M. Sees

The 482-hectare (ha) City of Orlando (Florida) Easterly Wetlands (OEW) was designed to reduce nutrient concentrations in 0.90 m3/s of wastewater from the Iron Bridge Regional Water Reclamation Facility. Design influent nutrient concentrations were 6 mg/L total nitrogen (TN) and 0.75 mg/L total phosphorus (TP). Actual TN and TP concentrations have been less than design, averaging 2.6 mg/L and 0.29 mg/L, respectively from January 1988 through December 1999. If influent concentrations remain at these levels, the OEW may have the potential to treat significantly higher flows since less than 20% of the total area was utilized for nutrient reduction. To test this theory, a capacity study was performed for approximately nine months in 1997 and 1998. Simulated flows of approximately 1.26 m3/s, 1.66 m3/s, and 1.93 m3/s were tested. It was found that approximately 15% of the area was utilized for nutrient reduction during the 1.26 m3/s simulation, 35% in the 1.66 m3/s, and 1.93 m3/s simulations. Based on these testing results, an application was submitted to the state in early 2000 to increase the permitted capacity to 1.57 m3/s.


1994 ◽  
Vol 8 (2) ◽  
pp. 35-46 ◽  
Author(s):  
L. B. Sumrall ◽  
R. Y. Surampalli ◽  
S. K. Banerji ◽  
D. M. Sievers

2011 ◽  
Vol 221 (1-4) ◽  
pp. 301-312 ◽  
Author(s):  
Michael M. Spacil ◽  
John H. Rodgers ◽  
James W. Castle ◽  
Cynthia L. Murray Gulde ◽  
James E. Myers

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