Long-Term Field-Scale Experiment on Using Lime Filters in an Agricultural Catchment

Abstract

Th e River Yläneenjoki catchment in southwest Finland is an area with a high agricultural nutrient load. We report here on the nutrient removal performance of three on-site lime-sand fi lters (F1, F2, and F3), established within or on the edge of the buff er zones. Th e fi lters contain burnt lime (CaO) or spent lime [CaO, Ca(OH) 2 , and CaCO 3 ]. Easily soluble lime results in a high pH level (>11) and leads to an effi cient precipitation of soluble phosphorus (P) from the runoff . Water samples were taken from the infl ow and outfl ow of each site in diff erent hydrological situations. Th e length of the monitoring period was 4 yr for F1, 6 yr for F2, and 1.5 yr for F3. F1 and F2 signifi cantly reduced the suspended solids (SS), total P (PTOT), and dissolved reactive P (DRP) in the treated water. Th e proportional reduction (%) varied but was usually clearly positive. Filter F3 was divided into two equal parts, one containing burnt lime and the other spent lime. Both fi lter parts removed PTOT and SS effi ciently from the water; the burnt-lime part also removed DRP. Th e mixed-lime part removed DRP for a year, but then the effi ciency decreased. Th e eff ect of fi lters on nitrogen compounds varied. We conclude that sand fi lters incorporating lime can be used together with buff er zones to reduce both P and SS load to watercourses.

Potential and limitations of phosphate retention media in water protection: A process-based review of laboratory and field-scale tests

“…The filter soon became clogged (Penn et al 2012). Kirkkala et al (2012) studied the efficiency of three buried filters of lime mixed with sand. In one of the filters, the sand was mixed with waste lime from a sugar refinery (i.e.…”

“…However, the relative retention (mass removal) was surprisingly similar for all three filters: 60-82% for TP and 46-60% for DRP. Even though the filters used by Kirkkala et al (2012) performed well during the monitoring periods, the authors discussed the possibility of P release after exhausting the lime. The two largest filters contained enough lime to maintain the pH of the effluent water throughout the study at about 10-12, which is a sufficiently high pH for efficient Ca-P precipitation.…”

Assessment of sorption properties and kinetic reaction of phosphorus reactive material to limit diffuse pollution

“…Contemporary trends of surface water protection against diffuse pollution include solutions, such as: creating buffer zones (Vought et al 1995), phosphorous wetland (Ulén et al 2013), biogeochemical barriers (Izydorczyk et al 2013), and different kind of removal structure and box fi lters (Kirkkala et al 2012, Penn et al 2012, Wang et al 2014, Sønderup et al 2015, Uusitalo et al 2015. Another method focused on P removal from agriculture areas are suspended reactive fi lters -SRFs (Karczmaczyk et al 2016).…”

“…Such materials may be used in a different form: box systems fi lled with RM (Penn et al 2012, Uusitalo et al 2015, barriers located at potential ways of surface runoff (Kirkkala et al 2012, Izydorczyk et al 2013 or hanging and submerged directly into treatment water (McDowell et al 2007, Karczmarczyk et al 2016. Reactive materials may also support P removal effi ciency at constructed wetland systems (Bus and Karczmarczyk 2017) or in geochemical barrier supporting buffer zones (Izydorczyk et al 2013).…”

Ecosystem change in the large and shallow Lake Säkylän Pyhäjärvi, Finland, during the past ~400 years: implications for management

“…A multitude of measures have been implemented in the catchment in order to reduce the external load (Kirkkala et al, 2012;Kirkkala, 2014). Pyhäjärvi has also been intensively biomanipulated for decades in the form of removal of planktivorous fish by commercial fishery.…”