Clean waste water before it enters the environment

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
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How is the evidence assessed?

Effectiveness

60%
Certainty

25%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

Waste water could be cleaned before it is released into peatlands or before it enters the environment in general (ultimately reaching peatlands). Excess nutrients, salts, heavy metals, radioactive materials and organic compounds should be removed. Acidity (pH) should be adjusted. Hot water should be cooled. Waste water could be treated using traditional industrial methods, or in ‘constructed wetlands’ that contain plants and microorganisms to absorb or break down pollutants (Kadlec et al. 2000).

Caution: Peatland vegetation is very sensitive to water chemistry (Rydin & Jeglum 2013). If cleaned waste water is being discharged directly into a peatland, its chemistry should be carefully controlled to match natural input water. Note that bogs receive their water only as rain, so are likely to be harmed by any other water inputs.

Key peatland types for which this action may be appropriate: bogs, fens/fen meadows, tropical peat swamps.

_{Kadlec R.H., Knight R.L., Vymazal J., Brix H., Cooper P. & Haberl R. (2000) Constructed Wetlands for Pollution Control: Processes, Performance, Design and Operation. IWA Publishing, London.}

_{Rydin H. & Jeglum J.K. (2013) The Biology of Peatlands, Second Edition. Oxford University Press, Oxford.}

Study locations

Key messages

One study evaluated the effect, on peatland vegetation, of cleaning waste water before it enters the environment. The study was in a fen.
Characteristic plants (1 study): One study in a floating fen in the Netherlands found that after input water began to be cleaned (along with other interventions to reduce pollution), cover of mosses characteristic of low nutrient levels increased.
Vegetation structure (1 study): The same study found that after input water began to be cleaned (along with other interventions to reduce pollution), vascular plant biomass decreased.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A study in 1984–2013 in a floating rich fen in the Netherlands (Kooijman et al. 2016) found that after installing water purification facilities (along with other interventions to reduce pollution), moss cover changed to species characteristic of lower nutrient levels whilst vascular plant biomass decreased. Over 25 years following intervention, four of seven moss species characteristic of low nutrient levels increased in cover (from 1–62% to 11–83%). Meanwhile, six of seven moss species characteristic of high nutrient levels decreased in cover (from 7–78% to 1–32%). Over 28 years, vascular plant biomass decreased from 1,123 g/m² to 287 g/m². Since the 1970s, water purification facilities were built to treat the fen water source (no further details reported), the water source was changed from a nutrient-rich river to a nutrient-poor lake, and the water was rerouted to allow more time for nutrient reduction. The study does not distinguish between the effects of these interventions. In addition, there was a general reduction in nutrient input from urban areas. In 1988 and 2013, cover of every moss species was recorded in a 25 x 200 m area. In 1984 and 2012, above-ground vascular plant biomass was collected, dried and weighed.
Study and other actions tested
Referenced paper
Kooijman A.M., Cusell C., Mettrop I.S. & Lamers L.P.M. (2016) Recovery of target bryophytes in floating rich fens after 25 yr of inundation by base-rich surface water with lower nutrient contents. Applied Vegetation Science, 19, 53-65.

Please cite as:

Taylor, N.G., Grillas, P. & Sutherland, W.J. (2020) Peatland Conservation. Pages 367-430 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Peatland Conservation

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