Use of wetland buffer areas to reduce nitrogen transport from forested catchments: Retention capacity, emissions of N2O and CH4 and vegetation composition dynamics

Hynninen, Anu

doi:10.14214/df.129

“…The 12 OFAs with good hydraulic function in our dataset typically showed a decrease in pollutant reductions with increasing hydraulic loading rates (Table 6), an effect that has been reported previously for P and N in buffer zones established in peatlands for forestry purposes (Hynninen, 2011;Hynninen et al 2011). Large amounts of water and high flow velocities limit the contact between the water and the peat, moss and vascular plant layers in OFAs and other peatland-based wetlands, and also shorten the residence time of the water for all purification processes, especially nitrification and denitrification.…”

Section: Hydraulic Loadingsupporting

confidence: 84%

“…This was probably mainly due to the quite small variation in Aw/Ac values in the data because of the existing system design instructions (Ihme et al, 1991b;Savolainen et al, 1996), but it may also be related to the fact that water was being pumped to most of the wetlands (25 wetlands out of the 28 studied) (Table 2), the pumps being used to control the amount of water released onto the wetlands. Increases in total-N and total-P reductions with increasing Aw/Ac ratios have been reported in constructed wetlands (Kadlec and Knight, 1996), in water pollution control wetlands in agriculture (Puustinen et al, 2007) and in peatland buffer zones used in forestry (Vikman et al, 2010;Hynninen et al, 2011).…”

Section: Hydraulic Loadingmentioning

confidence: 92%

Long-term purification efficiency and factors affecting performance in peatland-based treatment wetlands: An analysis of 28 peat extraction sites in Finland

Heikkinen

¹

,

Karppinen

²

,

Karjalainen

³

et al. 2018

Ecological Engineering

View full text Add to dashboard Cite

Peatland-based treatment wetlands that purify incoming water by means of natural physical, chemical and biological processes belonging to the peatland ecosystem are widely used at Finnish peat extraction sites. They can comprise either undrained or drained overland flow areas (OFAs or DOFAs), with the OFAs representing the best available technology (BAT) for peat extraction. We analyse here the long-term treatment performance of these OFAs and DOFAs and factors affecting this performance. Data on 14 OFAs and DOFAs in different parts of 2 Finland were taken from the extensive long-term environmental pollution control databases. Nearly half of these wetlands had been monitored for at least 4 years and seven for 8-23 years. The results indicated that peatland-based treatment wetlands purify drainage water as efficiently as other natural treatment wetlands on soils in general, the common challenge being phosphorus retention. Iron was also efficiently retained. The average reductions were highest in OFAs with good hydraulic function, and these also showed long-term water protection performance. An important factor affecting purification efficiency was the hydraulic loading rate. Important system design elements in this regard were the size of the wetland in relation to its catchment area, its gradient, the length of the water flow route within the wetland, and the efficient flow area of the wetland. The results regarding the latter two design elements strongly indicate that not all the areas potentially suitable in DOFAs for water purification are yet being used efficiently.

show abstract

“…In addition, the efficiency has been observed to be insufficient during peak/high flow periods (Liljaniemi et al, 2003), when the majority of the annual contaminant export takes place (Marttila and Kløve, 2009). Constructed wetlands and overland flow fields can also capture dissolved nutrients (Hynninen, 2011) through uptake by the vegetation and microbes, although the efficiency decreases outside the growing season when the nutrient uptake is suppressed due to low temperatures (Joensuu et al, 2002Nieminen et al, 2005b.…”

Section: Peatland Forestry and Water Protectionmentioning

confidence: 99%

“…Despite being maintenance-free and inexpensive, there are some detrimental impacts regarding buffer zones, particularly as their construction by rewetting and restoring drained peatland habitats potentially enhances nutrient outflow. In addition, buffer areas may increase nitrous oxide (N2O) and methane emissions (CH4) (Hynninen, 2011). It has been demonstrated that the riparian buffer zones that surround water bodies effectively retain soluble nutrients within the soil and plant systems (Vikman et al, 2010).…”

Section: Peatland Forestry and Water Protectionmentioning

confidence: 99%

Biochar as a water protection tool in peatland forestry – nutrient recovery from runoff water

Kakaei Lafdani

2023

Diss. For.

0

View full text Add to dashboard Cite

Water quality is significantly affected by the forest logging activities that are carried out in drained peatlands, which causes a notable enhancement in sediment loading and nutrient export to water bodies. Furthermore, the seasonal fluctuations in nutrient concentrations in the runoff further underscore the need for efficient water protection tools in peatland forestry. To address these issues, biochar-based adsorption methods can potentially offer an effective alternative for water protection in peatland forestry. The current thesis investigates the potential for adsorption-based nutrient recovery from clear-cut peatland runoff water using Norway spruce and Silver birch biochars. In particular, the aim is to i) study the adsorption characteristics in relation to biochar properties and nutrient compounds in runoff waters in a small-scale laboratory experiment (Paper I); ii) investigate the adsorption characteristics of nitrogen (N) compounds from runoff water in a meso-scale laboratory experiment that utilises biochar reactors (Paper II); and iii) investigate the dynamics of biochar adsorption and desorption under fluctuating total nitrogen (TN) concentrations in runoff water (Paper III). Biochar made from birch and spruce were shown to efficiently adsorb N compounds from the water. Across all experiments, the TN content declined significantly, irrespective of the scale, or whether the runoff volume ranged from litres (I and III) to hundreds of litres (II). Furthermore, the TN content at the beginning of the experiment declined at the fastest rate. The results indicate that cases of relatively low adsorption capacity were attributed to the low initial TN concentrations in the water. In addition, TN adsorption occurs above a threshold concentration in natural runoff water. The spruce did not adsorb TN when the concentrations in the runoff water fell below 0.4 mg L-1. In this thesis, biochar emerges as a compelling water protection solution, particularly in regions where clear-cut peatlands release substantial quantities of nutrients.

show abstract

“…In addition, the efficiency has been observed to be insufficient during peak/high flow periods (Liljaniemi et al, 2003), when the majority of the annual contaminant export takes place (Marttila and Kløve, 2009). Constructed wetlands and overland flow fields can also capture dissolved nutrients (Hynninen, 2011) through uptake by the vegetation and microbes, although the efficiency decreases outside the growing season when the nutrient uptake is suppressed due to low temperatures (Joensuu et al, 2002Nieminen et al, 2005b.…”

Section: Peatland Forestry and Water Protectionmentioning

confidence: 99%

Biochar as a water protection tool in peatland forestry – nutrient recovery from runoff water

Kakaei Lafdani

2023

Diss. For.

0

View full text Add to dashboard Cite

Water quality is significantly affected by the forest logging activities that are carried out in drained peatlands, which causes a notable enhancement in sediment loading and nutrient export to water bodies. Furthermore, the seasonal fluctuations in nutrient concentrations in the runoff further underscore the need for efficient water protection tools in peatland forestry. To address these issues, biochar-based adsorption methods can potentially offer an effective alternative for water protection in peatland forestry. The current thesis investigates the potential for adsorption-based nutrient recovery from clear-cut peatland runoff water using Norway spruce and Silver birch biochars. In particular, the aim is to i) study the adsorption characteristics in relation to biochar properties and nutrient compounds in runoff waters in a small-scale laboratory experiment (Paper I); ii) investigate the adsorption characteristics of nitrogen (N) compounds from runoff water in a meso-scale laboratory experiment that utilises biochar reactors (Paper II); and iii) investigate the dynamics of biochar adsorption and desorption under fluctuating total nitrogen (TN) concentrations in runoff water (Paper III). Biochar made from birch and spruce were shown to efficiently adsorb N compounds from the water. Across all experiments, the TN content declined significantly, irrespective of the scale, or whether the runoff volume ranged from litres (I and III) to hundreds of litres (II). Furthermore, the TN content at the beginning of the experiment declined at the fastest rate. The results indicate that cases of relatively low adsorption capacity were attributed to the low initial TN concentrations in the water. In addition, TN adsorption occurs above a threshold concentration in natural runoff water. The spruce did not adsorb TN when the concentrations in the runoff water fell below 0.4 mg L-1. In this thesis, biochar emerges as a compelling water protection solution, particularly in regions where clear-cut peatlands release substantial quantities of nutrients.

show abstract

Use of wetland buffer areas to reduce nitrogen transport from forested catchments: Retention capacity, emissions of N2O and CH4 and vegetation composition dynamics

Cited by 3 publications

References 96 publications

Long-term purification efficiency and factors affecting performance in peatland-based treatment wetlands: An analysis of 28 peat extraction sites in Finland

Long-term purification efficiency and factors affecting performance in peatland-based treatment wetlands: An analysis of 28 peat extraction sites in Finland

Biochar as a water protection tool in peatland forestry – nutrient recovery from runoff water

Biochar as a water protection tool in peatland forestry – nutrient recovery from runoff water

Contact Info

Product

Resources

About