Pruning stormwater biofilter vegetation influences water quality improvement differently in Carex appressa and Ficinia nodosa

Abstract

The maintenance of stormwater biofilter vegetation is conducted under local guidelines, which often include seasonal pruning. However, the effects that pruning has on water quality improvement remain unknown. This study used experimental columns to investigate the effects of pruning on effluent concentrations of nitrogen, phosphorus, and metals when planted with two common biofilter plant species, Carex appressa and Ficinia nodosa. Effluent was monitored in pruned, non-pruned, and unplanted control columns during a 70-day regrowth period, with monthly composite water sampling encompassing the flushed saturated zone water and effluent of each column to best represent a biofilter during a storm event. Differences between pruning treatments and the control were often species-specific and varied with nutrient type. No significant differences between treatments were found for total phosphorus, but pruning treatments affected nitrogen oxide removal in later sampling dates for F. nodosa, but not C. appressa. Total N and P removal ranged from 77-88% and 66-93%, respectively, by both pruned and non-pruned plants. The overall amount of N and P removed in the pruned biomass was 2.1 -3.5 times more than the estimated amount removed from the influent by the regrowth of the pruned columns alone during the regrowth period. Consequently, the amount of nutrients removed via pruning may significantly impact long-term removal. Cadmium, copper, lead, and zinc effluent concentrations were similar between treatments with removal efficiencies over 95%. Overall, pruning appears to affect water quality improvement, but optimal pruning practices that may enhance long-term removal should be investigated further.

Efecto de la poda de macrófitas sobre microorganismos adheridos al medio de soporte y la carga orgánica en humedales artificiales

“…Las plantas, al transferir oxígeno desde la atmósfera a través de hojas y tallos, lo liberan en las raíces creando regiones aerobias, donde los microorganismos utilizan el oxígeno disponible para la degradación de materia orgánica y la nitrificación, por lo que al podar las especies se modifican las microzonas aeróbicas en la superficie de las raíces y los rizomas (EPA, 2000;Rahman et al, 2020). Las poblaciones microbianas, por la variación del oxígeno, afectan la degradación de la materia orgánica, aunque autores como Herzog et al (2021) mencionan que los efectos que la poda tiene en la mejora de la calidad del agua siguen siendo desconocidos para ciertos contaminantes. En los HAFS parte de la carga orgánica se concentra en la entrada, por lo que, de acuerdo con Delgadillo et al (2010), los microorganismos heterótrofos requieren material orgánico como fuente de energía y carbono para la síntesis de nuevos microorganismos, lo que hace notar una mayor biomasa de microorganismos a la entrada del humedal que va disminuyendo en función a la longitud del humedal como consecuencia de la disminución de la materia orgánica hacia el efluente.…”

“…Por ello, un HAFS puede tener una menor superficie que un HAFL para los mismos caudales y calidad del agua (Conagua, 2016;Rahman et al, 2020). Los HAFS, al carecer de oxígeno, limitan la remoción del amoniaco (nitrificación), pero aun así el sistema es efectivo en la remoción de DBO (95.44 % para Tule y 87.5 % con Carrizo), algunos contaminantes como metales y orgánicos prioritarios, dado que el tratamiento es bajo condiciones aeróbicas y anóxicas (Herzog et al, 2021).…”

“…Las concentraciones de efluentes de cadmio, cobre, plomo y zinc fueron similares entre los tratamientos con remoción superior a 95 %. En general, la poda parece afectar la mejora de la calidad del agua, pero las prácticas óptimas de poda que pueden mejorar la eliminación a largo plazo (Herzog et al, 2021).…”

Potential of bioretention plants in treating urban runoff polluted with greywater under tropical climate

“…In addition, golden trumpet is fast-growing, and the aboveground plant structures certainly impact the bioretention system. Tall sedge is ranked fifth though it is indicated as a superior plant in past research for its excellent performance in stripping nutrients via bioretention system (Bratieres et al 2008;Ellerton et al 2012;Fowdar et al 2017;Herzog et al 2021;Read et al 2010). Tall sedge performed better in removing nutrients (TN & TP), which was observed to eliminate 84.3% and 93.4%, respectively.…”

Adaptive strategy biases in engineered ecosystems: Implications for plant community dynamics and the provisioning of ecosystem services to people

“…The nature of that filtering will likely depend both on the initial plant species selected and the type/magnitude of stress and disturbance experienced in local GSI. Common GSI stressors may include resource limitation (nutrients or water), transient inundation and metabolic injury from road salt or temperature extremes, among others (Farrell et al, 2013; Parker et al, 2021; Szota et al, 2015; Tu et al, 2020; Yuan & Dunnett, 2018), whereas common forms of disturbance may include erosive flows, wind scour, trampling and biomass loss due to grazing or maintenance activities such as pruning (Beryani et al, 2021; Dellinger et al, 2021; Herzog et al, 2021; Mazer et al, 2001). Accordingly, stress/disturbance profiles (and associated plant adaptive strategies) can be expected to vary in GSI, reflecting differences in initial plant selection, local/regional land use, climate regime and GSI type, as well as other factors.…”