Algae treatment

Algae treatment

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• Overview
• Key considerations
• Planning and design
• Construction and operation
• Links and references

Other name/s

Algae ponds, High Rate Algal Ponds (HRAPs), Bioremediation using macroalgae

Description:

The cultivation and subsequent harvest of freshwater or saline/marine macroalgae (seaweed) provides a way to sequester and remove nutrients (nitrogen and phosphorous) and other elements as a component of the biomass of macroalgae[5][2].

Macroalgae is usually cultivated in a mechanical treatment system, called a high-rate algal pond. These are shallow, raceway ponds that circulate wastewater via a paddle wheel (or similar) to continuously mix the water to maximise algal growth and hence nutrient removal.

The algal biomass takes up or absorbs nutrients from water as it grows and multiplies. Algal biomass is regularly harvested and can be used for various bio-products of value, such as energy, oils, fertiliser, soil amendment and stock feed.

The bioremediation system is robust, deals with high and very low nutrient regimes including variable loads and has been tested in various freshwater waste streams. It has been used to treat both nutrients and pathogens in sewage treatment plants[4]. A strength is the ability to quantify the nutrients removed and to deliver end-use value of these nutrients and the biomass offsetting the cost of treatment[1][2][7][6].

HRAP have been used to treat aquaculture wastewater from prawn farms and fish farms in north Queensland. Its use in agriculture systems like cane and horticulture has not been demonstrated, although investigation of cane farm run-off suggests they could be suitable[3].

The actual cost-effectiveness of an algae treatment system will depend on the specific site conditions and project objectives and needs to be considered relative to other treatment systems or management intervention options. Refer to cost considerations for more information.

Services and benefits:

• Water treatment (nutrients)
• Beneficial reuse of by-products

References

1. ^ Cole, AJ, de Nys, R & Paul, NA (2015), 'Biorecovery of nutrient waste as protein in freshwater macroalgae', Algal Research, vol. 7, pp. 58-65.
2. ^ a b Cole, AJ, Neveux, N, Whelan, A, Morton, J, Vis, M, de Nys, R & Paul, NA (December 2016), 'Adding value to the treatment of municipal wastewater through the intensive production of freshwater macroalgae', Algal Research. [online], vol. 20, pp. 100-109. Available at: https://linkinghub.elsevier.com/retrieve/pii/S2211926416304593 [Accessed 13 April 2022].
3. ^ Lawton, R (2015), Reduction of nutrient loads in sugarcane run-off water through algal bioremediation, MACRO — the Centre for Macroalgal Resources and Biotechnology, James Cook University, Queensland.
4. ^ Local Government Association of South Australia (June 2020), High Rate Algal Pond (HRAP) Design Guideline.pdf. [online] Available at: https://www.lga.sa.gov.au/__data/assets/pdf_file/0041/694787/High-Rate-Algal-Pond-HRAP-Design-Guideline-June-2020.pdf.
5. ^ 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].
6. ^ Neveux, N, Nugroho, AA, Roberts, DA, Vucko, MJ & de Nys, R (February 2020), 'Selecting extraction conditions for the production of liquid biostimulants from the freshwater macroalga Oedogonium intermedium', Journal of Applied Phycology. [online], vol. 32, no. 1, pp. 539-551. Available at: http://link.springer.com/10.1007/s10811-019-01925-3 [Accessed 13 April 2022].
7. ^ Treatment Systems for water quality improvement - Regional Forum (July 2018), 'Bioremediation of wastewater using freshwater macroalgae'. [online], Townsville, Queensland (Aus), ed. R de Nys. Available at: https://wetlandinfo.des.qld.gov.au/resources/static/pdf/management/regional-forum/3-de-nys.pdf.

Last updated: 27 June 2022