Survey of the operational status of twenty-six urban stormwater biofilter facilities in Sweden

Ali Beryani; Alisha Goldstein; Ahmed Mohammed Al-Rubaei; Maria Viklander; William F Hunt 3rd; Godecke-Tobias Blecken

doi:10.1016/j.jenvman.2021.113375

Survey of the operational status of twenty-six urban stormwater biofilter facilities in Sweden

J Environ Manage. 2021 Nov 1:297:113375. doi: 10.1016/j.jenvman.2021.113375. Epub 2021 Jul 26.

Authors

Ali Beryani¹, Alisha Goldstein², Ahmed Mohammed Al-Rubaei³, Maria Viklander⁴, William F Hunt 3rd⁵, Godecke-Tobias Blecken⁶

Affiliations

¹ Dept. of Civil, Environmental, and Natural Resources Engineering, Luleå Univ. of Technology, 97187, Luleå, Sweden. Electronic address: ali.beryani@ltu.se.
² Dept. of Biological and Agriculture Engineering, North Carolina State Univ., Campus Box 7625, Raleigh, NC, 27695, USA. Electronic address: aegolds2@ncsu.edu.
³ Dept. of Civil, Environmental, and Natural Resources Engineering, Luleå Univ. of Technology, 97187, Luleå, Sweden; Dept. of Building and Construction Engineering, Univ. of Technology, 19006, Baghdad, Iraq. Electronic address: ahmed@ltu.se.
⁴ Dept. of Civil, Environmental, and Natural Resources Engineering, Luleå Univ. of Technology, 97187, Luleå, Sweden. Electronic address: marvik@ltu.se.
⁵ William Neal Reynolds Professor and Extension Specialist, Dept. of Biological and Agriculture Engineering, North Carolina State Univ., Campus Box 7625, Raleigh, NC, 27695, USA. Electronic address: wfhunt@ncsu.edu.
⁶ Dept. of Civil, Environmental, and Natural Resources Engineering, Luleå Univ. of Technology, 97187, Luleå, Sweden. Electronic address: godble@ltu.se.

PMID: 34325375
DOI: 10.1016/j.jenvman.2021.113375

Abstract

This study evaluates the operational status of twenty-six biofilter facilities across nine cities in Sweden, with respect to their functional design criteria, engineered design features (filter media composition, hydraulic conductivity, and drawdown time), and includes a visual inspection of the biofilter components (pre-treatment, in/outlet structures, filter media, and vegetation). These indicators were used to examine the performance level of each biofilter in achieving their design objectives set by the operators. Furthermore, it was investigated whether the biofilter facilities had been properly maintained to meet the objectives. Results indicate that the soil media used was consistent with respect to percentage sand, fines, and organic matter and comparable to design recommendations used by municipalities in other countries. The field-tested hydraulic conductivity for the biofilters ranged from 30 to 962 mm/h. This range of values, along with noticeable sediment accumulation within the biofilter indicate that not all the sites were operating optimally. Pre-treatment stages in poor condition with high volumes of sediment and litter accumulation were the primary causes for, and indicators of, low hydraulic conductivity rates. The ponding volume calculations revealed that at least 40 % of facilities did not have enough capacity to retain every-day and/or design rainfall due to design and/or construction flaws. These analyses raise concerns that, for a considerable number of the biofilters surveyed, water retention and flood protection identified by operators as prioritised objectives are not being met. This raises significant concerns about the functionality of biofilter in practice. Finally, some suggestions are given for tackling the design and maintenance problems discovered.

Keywords: Asset management; Bioretention; Operation & maintenance; Stormwater control measures (SCMs); Urban stormwater management.

MeSH terms

Cities
Filtration*
Rain
Soil
Sweden
Water Purification*

Substances

Soil