Treatment systems

Treatment systems for improving water quality are engineered and designed to intercept, slow down and remove pollutants from water. Treatment systems are an engineered system which may be a suitable management option when the main goal or objective is water quality improvement. Pollutants such as sediments, nutrients and other toxicants (pesticides, heavy metals etc.) from urban, industrial and agricultural land uses, can enter wetlands and coastal or marine environments. Improving water quality from catchment land uses, is essential to maintain or improve the health and resilience of these ecosystems. Treatment systems, when used in conjunction with best practice land management, can improve water quality and in turn aquatic ecosystem health on a catchment scale.

Quick info links:

• Specific treatment system info - see landscape diagram below
• Compare treatment systems - see Table 1 below
• Create a fact sheet – see user defined template
• Planning and designing a treatment train and treatment systems for farms - see treatment systems in agriculture page
• Treatment systems for urban areas
• Treatment systems for industrial or intensive land uses

Treatment systems are designed to use natural wetland hydrologic, physical, biological or chemical processes and components (parts of the system e.g. soil, vegetation etc.) to remove specific pollutants from water (Table 1). No single treatment system is efficient in treating all pollutants. That is why multiple treatment systems are often combined to form a treatment train.

Treatment systems complement, but do not replace the need for measures to prevent the loss of pollutants from the source, such as erosion control (e.g. pile fields, ground cover) or to implement nutrient, sediment, chemical and water best management practices. They should be considered as part of a whole of system approach to catchment management and are thus one option under aquatic ecosystem rehabilitation. Best management practices are the essential first step in any treatment train to prevent or minimise pollutants.

The treatment system or treatment train must be designed for the quantity and quality of water entering the treatment system. Loads of sediments, nutrients or other toxicants above the design criteria will overload, and often, damage treatment systems, causing them to stop working effectively and potentially lead to costly maintenance and repair. Likewise, directing relatively clean water, such as runoff from undeveloped land, away from treatment systems leads to a more effective treatment system by ensuring that only the water requiring treatment enters the treatment system.

Click for more information on - Treatment systems for agriculture (including aquaculture) focuses on systems to treat pollutants in food and fibre production systems; Urban stormwater treatment and water sensitive urban design (WSUD) focuses on systems to treat pollutants in urban environments; Other intensive land use treatments focuses on systems to treat pollutants from industrial activities, sewage treatment and other intensive uses.

Treatment systems can be used at a range of scales from house block or paddock scale, through to regional scale systems treating runoff from multiple properties or a sub-catchment. The type, design and operation of a treatment system and treatment train depends on several factors including:

• the components and processes of the site and catchment characteristics including:
  • hydrology (e.g. water flows during different seasons, run-off, groundwater, natural wetland systems, waterway connectivity)
  • soils
  • topography
  • land use (agriculture, aquaculture, urban, industrial, or intensive)
• services and values of the surrounding and downstream environment
• the goals and objectives of the works and specific water quality targets for the catchment or region
• existing management to reduce pollutants, including other treatment systems
• the type of pollutant, pollutant removal process, level of treatment required and volume of water to be treated
• available budget and likely costs including construction, operating, maintenance and monitoring
• the degree of acceptance and potential impacts on the community, including consideration of beneficiaries and stakeholders, and First Nations connections to the land and aquatic ecosystems.
• Treatment systems in agriculture and each treatment system option provides more detail on planning and designing treatment systems and treatment trains.

Treatment system effectiveness

Treatment systems are designed for pollutant removal, although they can provide other services or benefits (Table 1). If the objective of the system is to provide habitat or other ecosystem services, also read about aquatic ecosystem rehabilitation.

Table 1 Treatment processes, effectiveness and relative complexity of different treatment systems for water quality improvement.

¹Confidence is based on peer-reviewed publications on trials in Queensland in a variety of settings. This also indicates confidence in the design requirements to maximise treatment performance.

²Other biotic characteristics include habitat for insects, small fish, birds and threatened species[2].

Note: refer to cost considerations for more information on the potential costs of different treatment systems.

Treatment system modelling

Hydrological models can be used to assist in the choice and design of treatment systems. Water modelling is the process of developing mathematical and logic-based representations of real-world relationships between different variables[4]. A range of numerical models are available to simulate the sediment and nutrient removal performance of wetlands and other treatment systems[4][3].  It is important to select a suitable model for the intended purpose and adjust the model parameters appropriately for the location[3][1]. Hydrological and water quality data is required to calibrate and validate any model. This may be available from public sources or site-specific monitoring may be required to enable a model to be developed[4]. Expert advice is generally required to choose and construct a hydrological model. The Queensland Water Modelling Network (QWMN) provides tools, information and collaborative platforms to support best-practice use of water models.

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. If you have any additional information on treatment systems or suggestions for additional technologies contact us via the feedback link at the bottom of the page.

Additional information

How much nitrogen can vegetated drains remove?

Beyond the Block factsheets – Improving water quality at the edge of block

Using denitrifying bioreactors to improve water quality on Queensland farms

Melbourne Water—options for treating stormwater

The Nature Conservancy – Leading at the edge: a roadmap to advance edge of field practices in agriculture

Minnesota Pollution Control Agency—Processes for removing pollutants from stormwater runoff

A model for urban stormwater improvement conceptualization. Global Solutions for Urban Drainage

Bakers Creek Treatment Train - drone footage

Pages under this section

References

1. ^ Botelho, D, Singh, A, Rissik, D, Hipsey, M & Gibbes, B (2021), Queensland Water Modelling Network: Strategic Review of Models, p. 10, Department of Environment and Science, Queensland Government, Brisbane.
2. ^ Neveux, N, Magnusson, M, Mata, L, Whelan, A, de Nys, R & Paul, NA (January 2016), 'The treatment of municipal wastewater by the macroalga Oedogonium sp. and its potential for the production of biocrude', Algal Research. [online], vol. 13, pp. 284-292. Available at: https://linkinghub.elsevier.com/retrieve/pii/S2211926415301247 [Accessed 27 June 2022].
3. ^ a b Queensland Water Modelling Network (2018), QWMN water model catalogue. [online] Available at: https://watermodelling.org/resources/qwmn-water-model-catalogue.
4. ^ a b c Weber, T, de Groot, A, Hamilton, D, Yu, S & Bayley, M (2021), QWMN Wetlands Hydrology Models Review, Alluvium Consulting Australia, Griffith University, and Australian Wetlands Consulting.

Last updated: 27 June 2022