Treat fine sediments, nutrients and other toxicants

Fine sediments, nutrients bound to particles (particulate nutrients), dissolved nutrients and toxicants (including pesticides, herbicides, heavy metals) can be exported from modified systems through surface runoff or leaching/deep drainage into groundwater. These pollutants can cause eutrophication, alter primary productivity and food webs and kill sensitive plants and animals in waterways, wetlands and marine environments. Fine sediments, nutrients and toxicants can be transported long distances affecting aquatic and marine environments far from the source of the pollutant. Treatment systems for agricultural water quality improvement can remove these pollutants from surface or groundwater runoff through a range of physical, chemical and biological processes. Treatment systems need to be specifically designed to maximise the treatment processes for the target pollutant.

Quick facts

Denitrification

is the dominant nitrogen removal process in wetlands[1].

Which treatment systems can I use?

• Algae treatment
• Bioreactor
• Floating wetland
• High efficiency sediment basin
• Recycle pit
• Treatment wetland

Fine sediments, nutrients and other toxicants from agricultural production systems can affect the health and resilience of wetlands, inshore and marine environments, such as the Great Barrier Reef[6]. Fine sediments, nutrients (particulate or dissolved) and other toxicants (e.g. herbicides, pesticides and heavy metals) alter primary production and food webs, cause eutrophication, harmful algae blooms and kill sensitive plants and animals, leading to significant changes in aquatic communities.

Numerous physical, biological and chemical processes act to remove, transform, sequester and adsorb/absorb fine sediments, nutrients and other toxicants (Table 1). Different treatment systems for agricultural water quality improvement can be selected or tailored to the pollutant/s being generated in the agricultural production landscape (Table 2). Individual treatment systems are designed to enhance natural physical, biological and chemical treatment processes, targeted at specific types of pollutants and use the specific components and processes of these systems to do so. Understanding the treatment processes and the nature of the pollutant helps to identify what features (components and processes) are needed in the treatment system to effectively remove the target pollutant/s. For example, in the case of herbicides the physiochemical properties (e.g. the soil adsorption coefficient Koc) and half-life of each chemical will determine the most appropriate treatment processes[5].

Disclaimer

In addition to the standard disclaimer located at the bottom of the page, please note the content presented is based on published knowledge of treatment systems. Many of the treatment systems described have not been trialled in different regions or land uses in Queensland. The information will be updated as new trials are conducted and monitored. If you have any additional information on treatment systems or suggestions for additional technologies please contact us using the feedback link at the bottom of this page.

References

1. ^ Bachand, PAM & Horne, AJ (2000), 'Denitrification in constructed free-water surface wetlands: II. Effects of vegetation and temperature.', Ecological Engineering. [online], vol. 14, pp. 17-17-32. Available at: https://www.researchgate.net/publication/248412481_Denitrification_in_Constructed_Free-Water_Surface_Wetlands_II_Effects_of_Vegetation_and_Temperature.
2. ^ Melbourne Water (28 September 2017), Constructed wetlands. [online], Melbourne Water. Available at: https://www.melbournewater.com.au/planning-and-building/developer-guides-and-resources/standards-and-specifications/constructed-0 [Accessed 27 February 2018].
3. ^ Minnesota Pollution Control Agency (14 July 2017), Processes for removing pollutants from stormwater runoff. [online], Minnesota Pollution Control Agency. Available at: https://stormwater.pca.state.mn.us/index.php?title=Processes_for_removing_pollutants_from_stormwater_runoff [Accessed 29 July 2018].
4. ^ Osmond, DL, Line, DE, Gale, JA, Gannon, RW, Knott, CB, Bartenhagen, KA, Turner, MH, Coffey, SW, Spooner, J, Wells, J, Walker, JC, Hargrove, LL, Foster, MA, Robillard, PD & Lehning, DW (1997), 'WATERSHEDSS: Water, Soil and Hydro-Environmental Decision Support System', Journal of the American Water Resources Association. [online], vol. 33, no. 2, pp. 327-341. Available at: https://www.epa.gov/ceam/watershedss.
5. ^ Vymazal, J & Brezinova, T (2015), 'The use of constructed wetlands for removal of pesticides from agricultural runoff and drainage: a review', Environment International, vol. 75, pp. 11-20.
6. ^ Waterhouse, J, Schaffeike, B, Bartley, R, Eberhard, R, Brodie, J, Star, M, Thorborn, P, Rolfe, J, Ronan, M, Taylor, B & Kroon, F (2017), Scientific Consensus Statement, The State of Queensland, Brisbane.
7. ^ Wong, T, Fletcher, T, Duncan, H, Coleman, J & Jenkins, G (2002), 'A model for urban stormwater improvement conceptualization', Global Solutions for Urban Drainage, vol. 8, no. 13.

Last updated: 10 October 2018