Intra-event variations of organic micropollutants in highway runoff and a presedimentation-biofilter treatment facility.

The study assessed the quality of highway runoff and a stormwater treatment system, focusing on intra-event variations (IEVs: variations within a runoff/effluent event) of the concentration of organic micropollutants (OMPs) including bisphenol-A, alkylphenols, polycyclic aromatic hydrocarbons (PAHs), and petroleum hydrocarbons (PHCs). IEVs of OMPs varied considerably with no particular recurring pattern in highway runoff and presedimentation effluent, displaying sporadic strong first flushes. IEVs are significantly associated with rainfall intensity variations, especially for particle-bound substances such as PAHs and PHCs.

Accumulation and contamination of gully pot sediments from varied land-use types: metal loads, concentrations and speciation.

Urban stormwater typically enters sewer networks through gully pots, which allow a primary sedimentation of solids upstream of the piped network. The regular removal and disposal of retained sediment are necessary, costly and can involve environmental risks due to the contamination of sediments with substances from the urban environment such as metals. The concentrations and speciation of Cd, Cr, Cu, Ni, Pb and Zn were analysed in sediments from 26 gully pots located in different land use areas in Stockholm, Sweden.

Performance of a gross pollutant trap-biofilter and sand filter treatment train for the removal of organic micropollutants from highway stormwater (field study).

This field study assessed the occurrence, event mean concentrations (EMCs), and removal of selected organic micro-pollutants (OMPs), namely, polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons (PHCs), nonylphenol (NP), 4-t-octylphenol (OP), and bisphenol A (BPA), in a gross pollutant trap (GPT)-biofilter/sand filter stormwater treatment train in Sundsvall, Sweden. The effects of design features of each treatment unit, including pre-sedimentation (GPT), sand filter medium, vegetation, and chalk amendment, were investigated by comparing the units' removal performances. Overall, the treatment train removed most OMPs from highway runoff effectively.

A study of 101 organic substances in gully pot sediments accumulated over a one-year period in Stockholm, Sweden.

Stormwater runoff is a key pathway for diffuse pollutants to enter receiving waters. Mitigating measures include pollutant substitution, restricting their release into the urban technosphere and limiting the (re-)mobilisation of substances to minimise their negative impacts on receiving waters. Gully pots (GPs) are one of the most ubiquitous urban drainage infrastructure components, providing both a drainage function and limiting the onward transport of pollutants through in-pot sedimentation processes.

Occurrence and concentrations of organic micropollutants (OMPs) in highway stormwater: a comparative field study in Sweden.

This study details the occurrence and concentrations of organic micropollutants (OMPs) in stormwater collected from a highway bridge catchment in Sweden. The prioritized OMPs were bisphenol-A (BPA), eight alkylphenols, sixteen polycyclic aromatic hydrocarbons (PAHs), and four fractions of petroleum hydrocarbons (PHCs), along with other global parameters, namely, total organic carbon (TOC), total suspended solids (TSS), turbidity, and conductivity (EC). A Monte Carlo (MC) simulation was applied to estimate the event mean concentrations (EMC) of OMPs based on intra-event subsamples during eight rain events, and analyze the associated uncertainties.

Green infrastructure drainage of a commercial plaza without directly connected impervious areas: a case study.

A paired-catchment study of two adjacent commercial areas in northern Sweden, one with Green Infrastructure (GI) storm drainage and the other with a conventional storm sewer system, served to evaluate the hydrological performance of both drainage systems and demonstrate advantages of GI. The GI catchment avoided directly connected impervious areas by diverting runoff from a parking lot to a cascade of three infiltration features, a fractured rock strip draining onto a sloping infiltration area, followed by a collector swale. Both catchments were monitored over 4 years by measuring rainfall, runoff and, in the vicinity of the swale, soil water content and groundwater levels.

Variability of green infrastructure performance due to climatic regimes across Sweden.

In the context of increasing urbanization and global warming, there is a growing interest in the implementation of green infrastructure (GI) across different climates and regions. Identifying an appropriate GI design criteria is essential to ensure that the design is tailored to satisfy local environmental requirements. This article aims to compare the hydrological performance of GI facilities in eleven Swedish cities by isolating the effect of climatic conditions using an identical GI design configuration.

Occurrence, concentration, and distribution of 38 organic micropollutants in the filter material of 12 stormwater bioretention facilities.

The increased use of bioretention facilities as a low impact development measure for treating stormwater runoff underscores the need to further understand their long-term function. Eventually, bioretention filter media must be (partly) replaced and disposed of at the end of its functional lifespan. While there are several studies of metal accumulation and distributions in bioretention media, less is known about organic pollutant pathways and accumulation in these filters.

Facilitating maintenance of stormwater ponds: comparison of analytical methods for determination of metal pollution.

Stormwater ponds are widely used for controlling runoff quality through the sedimentation of particles and associated pollutants. Their maintenance requires regular removal and disposal of accumulated material. This necessitates an assessment of material hazardousness, including potential hazard due to its contamination by metals.

Contamination of Urban Stormwater Pond Sediments: A Study of 259 Legacy and Contemporary Organic Substances.

Stormwater ponds improve water quality by facilitating the sedimentation of particles and particulate contaminants from urban runoff. Over time, this function entails the accumulation of contaminated sediments, which must be removed periodically to maintain a pond's hydraulic and treatment capacity. In this study, sediments from 17 stormwater sedimentation facilities from four Swedish municipalities were analyzed for 259 organic substances likely to be found in the urban environment.

Zirconium deficit as a tracer of urban sediment accumulation in Sustainable Urban Drainage Systems - Application to the calibration of a filtration model.

Among the processes governing contaminant retention in soil-based Sustainable Urban Drainage Systems (SUDS), quantifying the relative contribution of particle settling and filtration requires a tracer of runoff-generated solids. Since zirconium (Zr) is a widely used geochemical invariant in pedological approaches, with few anthropogenic sources, the present investigation aims to assess whether its use may be extended to sediment identification in SUDS. High-resolution horizontal and vertical soil sampling was carried out in 11 infiltration systems, as well as in road-deposited sediment.

Retention and transport processes of particulate and dissolved micropollutants in stormwater biofilters treating road runoff.

Road runoff is contaminated by various micropollutants and may be treated using low impact development techniques, such as stormwater biofilters. Better understanding the processes, such as filtration, sorption and leaching, which affect pollutants in these systems is essential to reliably predicting treatment performance and optimizing system design. Field data from an in situ monitoring campaign, wherein dissolved and particulate concentrations of a wide range of micropollutants (trace metals, polycyclic aromatic hydrocarbons, bisphenol-A, alkylphenols and phthalates) were characterized in untreated road runoff and biofilter outlets for 19 rain events, are used to explore transport and retention processes.

Field performance of two biofiltration systems treating micropollutants from road runoff.

The treatment efficiency of a vegetative filter strip and a biofiltration swale treating heavily loaded road runoff are evaluated. Concentrations measured in water drained from the two systems are compared to those in untreated road runoff collected from a reference catchment for a wide range of contaminants including organic carbon, nutrients (N and P), trace metals, and organic micropollutants (polycyclic aromatic hydrocarbons (PAH), total petroleum hydrocarbons (TPH), alkylphenols, bisphenol-A, phthalates), in both total and dissolved phases. Predominantly particulate pollutants, including Pb, Zn and PAH, were very efficiently removed (around 90%) for most events.

Evaluation of the relative roles of a vegetative filter strip and a biofiltration swale in a treatment train for road runoff.

In order to determine the relative importance of a vegetative filter strip and a biofiltration swale in a treatment train for road runoff, US EPA Storm Water Management Model was used to model infiltration and runoff from the filter strip. The model consisted of a series of subcatchments representing the road, the filter strip and the side-slopes of the swale. Simulations were carried out for different rain scenarios representing a variety of climatic conditions.