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Bioreactors — Construction and operation

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A range of legislation and approvals may be required for the construction of a bioreactor. Contact your local government before any construction is undertaken to understand requirements.

Prior to construction, check for any existing infrastructure by contacting electricity, water and telecommunication providers.

Engineering advice should be sought prior to construction to ensure the bioreactor is sized and sited appropriately, taking into account soil suitability, groundwater and local hydrology.


Bioreactors will require earthworks to excavate a trench or pit.

For beds, an inlet and outlet into a farm drain or subsurface drain also need to be constructed and can be either an open drain or pipe.

Consider using a berm, or diversion bank, if surface flows across or over the site could be large and may damage the bioreactor through scouring and/or topsoil loss or deposition[1].

Consider using geofabric on top of the woodchip to prevent sedimentation/clogging of woodchip media over time. This will also allow the woodchip to be exposed later in the project if desired[1].

Time for establishment

A bioreactor can be constructed and operational within one to two days (will depend on the size of the structure and any associate pipe work or structures). Denitrification will commence almost immediately. The denitrifying microbes are naturally present in the environment, no ‘seeding’ is required.


Operational requirements are minimal. Bioreactors operate passively.


Typical maintenance will involve:

  • Occasional excavation of sediment trap to remove sediment buildup.
  • Occasional cleaning of inlet and outlet structures.


Check sediment traps.

Check inlet and outlet structures for blockages.

Measure flows and nitrate removal for ongoing design purposes.

Lifespan/replacement time

Over time bioreactor performance will decline but some have been operating for more than a decade. Expected life is 10-20 years depending on the location and the type of carbon source. After this time the carbon source will need to be added to or replaced[2].


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.


  1. ^ a b Queensland Department of Agriculture and Fisheries (2018), Bioreactors: key aspects for effective design, operation and monitoring - Interim guideline for bioreactor trials July 2018. [online], Queensland Department of Agriculture and Fisheries, Queensland. Available at:
  2. ^ Schipper, L, Robertson, WD, Gold, AJ, Jaynes, DB & Cameron, SC (2010), 'Denitrifying bioreactors—An approach for reducing nitrate loads to receiving waters', Ecological Engineering, vol. 36, pp. 1532-1543.

Last updated: 5 October 2018

This page should be cited as:

Department of Environment and Science, Queensland (2018) Bioreactors — Construction and operation, WetlandInfo website, accessed 13 May 2021. Available at:

Queensland Government
WetlandInfo   —   Department of Environment and Science