Belinda Hatt

• BAppSc (Env Sc Hons), GCHE, PhD
• Lecturer at Monash University (Australia)

Headwater streams are critical to the integrity of the stream network; yet they are being rapidly degraded, channelised or lost through land-cover and land-use change, particularly in urbanizing areas. We refined the definition of a headwater stream, reviewed the headwater stream ecosystem literature and identified four critical knowledge gaps whic...

Stormwater biofilters are one of the most widely used nature-based solutions for urban water management. In the last 20 years, biofilters have been extensively studied for their pollutant removal performance; however, their application in the field is limited by high maintenance requirements. In this work, we propose the concept of zero additional...

To extend the application of stormwater biofilters (known also as bioretention systems or raingarden) under varied climate conditions, the concept of dual-mode biofilters (i.e., a biofilter that treats two sources of water) has recently emerged. However, studies of these systems have been limited to the laboratory-scale, and validation of the new c...

Biofiltration systems can help mitigate the impact of urban runoff as they can treat, retain and attenuate stormwater. It is important to select the optimal design characteristics of biofilters (e.g., vegetation, filter media depth) to ensure high treatment performance. Operational conditions (e.g., infiltration rate) can also lead to significant c...

Green walls that effectively treat greywater have the potential to become a part of the solution for the issues of water scarcity and pollution control in our cities. To develop reliable and efficient designs of such systems, the following two research questions were addressed: what would be the optimal design of a green wall for greywater treatmen...

The use of stormwater biofilters (also known as bioretention systems and raingardens), in tropical and semi-arid areas is hindered by seasonal rainfall patterns which cause extended dry periods. These periods can result in plant die-off, long-term damage to system health and leaching of pollutants when stormwater inflows resume. Using an additional...

Food production in a rapidly expanding population requires a larger quantity of water for irrigation. However, in an era where competition for finite potable water resources is increasing, alternative water sources should be considered. Stormwater presents a potential source of water that is abundant in urban areas. However, stormwater is contamina...

While biofilters are a stormwater treatment technology there is also the potential to use biofilters for urban agriculture, given that they are vegetated systems. However, it has been found that vegetables irrigated with stormwater can contain concentrations of cadmium (Cd) and lead (Pb) that exceed the guidelines set by the World Health Organizati...

The intermittent nature of stormwater runoff impacts the treatment performance of biofilters, also known as stormwater biofiltration or bioretention systems and raingardens. During extended dry periods, which are common even in temperate climates, plants can perish, creating unattractive and non-functional systems that might leach pollutants during...

Green walls, installed on the side of the buildings, mainly for their aesthetics and micro climate benefits, could become effective on-site greywater treatment solutions. However, far more research is needed to convert these nature-based systems into low-cost water purification technologies. This process study presents the first step in development...

To increase the resilience and liveability of cities and to maintain their productivity, green infrastructure is being highly viewed as a sustainable development strategy. Green infrastructure or technologies, essentially, represent a set of engineered elements providing multiple ecosystem services at building and urban scales. They aim to integrat...

The microbial community and function along with nitrate/nitrite (NOx) removal rates, and nitrogen (N) partitioning into “uptake”, “denitrification” and “remaining” via isotope tracers, were studied in soil bioretention mesocolumns (8 unique plant species). Total denitrification gene reads per million (rpm) were positively correlated with % denitrif...

Nitrogen is a pollutant of great concern when present in excess in surface waters. Living wall biofiltration systems that employ ornamentals and climbing plants are an emerging green technology that has recently demonstrated significant potential to reduce nitrogen concentrations from greywater before outdoor domestic re-use. However, there still e...

Green walls are increasingly being considered as a suitable greywater treatment technology. Nevertheless, until now there have been no clear recommendations for the use of effective lightweight media in greywater treating green walls. Previous studies of potentially suitable growing media have suggested that a combination of perlite and coco coir m...

Short term studies have found that stormwater biofiltration systems, also known as bioretention systems or raingardens, are very effective in reducing heavy metal concentrations. However, their long-term treatment performance, as well as the spatial and temporal accumulation of metals within these systems remain uncertain. This paper reports on a l...

Plant species are diverse in form, function and environmental response. This provides enormous potential for designing nature-based stormwater treatment technologies, such as biofiltration systems. However, species can vary dramatically in their pollutant-removal performance, particularly for nitrogen removal. Currently, there is a lack of informat...

Stormwater biofilters are an important part of the urban landscape in many Australian cities. Until recently, plant species have been selected primarily for their survivability and aesthetics. However, recent research has identified specific species that enhance biofilter functions such as pollutant removal and flood prevention (via infiltration)....

Plants play a critical role in the nutrient removal performance of stormwater biofilters. However, the influence of biofilter design on plant growth and subsequent implications for treatment performance are not well understood. A 12 month, laboratory-scale biofilter column experiment was conducted to investigate the response of Carex appressa to va...

Stormwater biofilters are important tools for managing runoff in urban watersheds. To the authors’ knowledge, there have been no accounts examining the presence of mycorrhizal fungi in biofilters. This plant–fungi relationship is an important interaction in most terrestrial ecosystems, playing a role in nutrient dynamics, water cycling, and soil or...

Green walls offer multiple benefits to urban environments, but they are major water consumers and not optimal for use in dry climates. If green walls were engineered to treat greywater, they could become cost-effective and more widespread. However, it is not clear what impact watering green walls with greywater has on the life cycle of plants and m...

Stormwater biofilters are dynamic environments, supporting diverse processes that act to capture and transform incoming pollutants. However, beneficial water treatment processes can be accompanied by undesirable greenhouse gas production. This study investigated the potential for nitrous oxide (N2O) and methane (CH4) generation in dissolved form at...

Phosphorus, a critical environmental pollutant, is effectively removed from stormwater by biofiltration systems, mainly via sedimentation and straining. However, the fate of dissolved inflow phosphorus concentrations in these systems is unknown. Given the growing interest in using biofiltration systems to treat other polluted waters, for example gr...

Greywater is being increasingly used as an alternative water source to reduce potable water demand and to alleviate pressure on sewerage systems. This paper presents the development of a low energy and low maintenance greywater treatment technology: a living wall system, employing ornamental plants (including vines) grown in a sand filter on a side...

The application of biofilters for the treatment of stormwater runoff is well-understood with studies currently underway to further improve its treatment reliability not only for improving the health of water bodies but also for harvesting treated stormwater runoff for non-potable usage. This study investigates the potential of extending the use of...

Biofiltration has been shown to be an effective technology for urban stormwater treatment and provides promise for greywater treatment. This paper presents the preliminary results of a laboratory-scale study undertaken to test the viability of a dual-mode stormwater-greywater biofilter. Forty-eight biofilter columns utilising eight different plant...

An external electron donor is usually included in wastewater and groundwater treatment systems to enhance nitrate removal through denitrification. The choice of electron donor is critical for both satisfactory denitrification rates and sustainable long-term performance. Electron donors that are waste products are preferred to pure organic chemicals...

Urban stormwater runoff degrades the ecological condition of streams. The use of rainwater tanks to supplement water supply can reduce the frequency and volume of urban stormwater runoff that is otherwise conveyed directly to streams via conventional stormwater drainage systems. Few studies, however, have examined the use of tanks in the context of...

Restoration and protection of urban stream ecosystems requires knowledge of the primary causes of their degradation. Conventional stormwater drainage has been identified as a primary source of stress to streams, but it remains unclear if the proximal stressor to stream biota can be represented by flow regime alone, or requires a metric integrating...

Key Points • Rapid urban sprawl in major cities and centres throughout Australia with conventional stormwater drainage may have unaccounted impacts and costs for downstream waterways. • Alternative stormwater management in greenfield developments, such as stormwater harvesting and biofiltration, can generate local benefits, cost savings and avoided...

Key Points • Contaminants to streams can be associated with specific sediment sizes from urban catchments • Heavy metals are mostly attached to medium sand and smaller particles (<500 µm). • PAHs are more associated with particles smaller than fine sands (<250 µm). • Far less is known about the association between sediment particle size and TN, TP,...

Biofilters have been shown to effectively treat stormwater and achieve nutrient load reduction targets. However, effluent concentrations of nitrogen and phosphorus typically exceed environmental targets for receiving water protection. This study investigates the role of filter media, vegetation and a saturated zone (SZ) in achieving co-optimised ni...

The long-term efficacy of stormwater treatment systems requires continuous pollutant removal without substantial re-release. Hence, the division of incoming pollutants between temporary and permanent removal pathways is fundamental. This is pertinent to nitrogen, a critical water body pollutant, which on a broad level may be assimilated by plants o...

The use of biofilters to remove nitrogen and other pollutants from urban stormwater runoff has demonstrated varied success across laboratory and field studies. Design variables including plant species and use of a saturated zone have large impacts upon performance. A laboratory column study of 22 plant species and designs with varied outlet configu...

Biofiltration systems harness the treatment capabilities of plants, microorganisms, and soil to mitigate impacts of polluted stormwater. However, their effectiveness for nitrogen removal can vary, from concentration reductions exceeding 70% to net leaching. Performance is particularly sensitive to plant species selection, presence of a saturated zo...

Biofiltration systems represent an effective technology for the management of urban stormwater runoff volumes and quality. The performance of these systems, although largely dependent on their physical characteristics, is also strongly affected by the natural variability of runoff occurrence and volumes. This article presents a model that describes...

Conventional approaches to stormwater management for environmental protection fail because they do not address all of the changes to the flow regime caused by conventional stormwater drainage. In this paper, we contrasted the hydrologic effects of two conventional approaches to urban stormwater management – (a) drainage-efficiency focused and (b) p...

Biofiltration systems are widely used to mitigate the impacts of stormwater on receiving waters, however their long-term capacity to retain heavy metals has not previously been assessed. Accelerated-dosing laboratory experiments were used to assess the likelihood of breakthrough occurring for three different types of soil-based filter media that ar...

Urbanisation results in changes to runoff behaviour which, if not addressed, inevitably degrade receiving waters. To date, most stormwater management has focussed on the streetscape and public open space. Given that much of the catchment imperviousness is located on private land, we developed and tested a novel economic instrument (a uniform price...

Biofilters can be used as a tool to treat urban stormwater and help combat the pollution of watercourses, whilst also offering the opportunity to attenuate and retain stormwater flows. However, their large scale implementation is being hindered by lack of knowledge about the key factors that influence their ability to remove pollutants from stormwa...

Urban stormwater is a major contributor of nutrient pollution to receiving waterways. Given the sensitivity of receiving waters to limiting nutrients, in particular phosphorus, stormwater presents a serious challenge. Biofiltration has proven to be a successful technology for the treatment of urban stormwater, being easily integrated into streetsca...

Biofiltration systems represent an increasingly popular technology for the management of urban stormwater runoff. The performance of these systems, largely dependent on their physical characteristics, is also strongly affected by the natural variability of runoff occurrence and volumes. We present here a model to quantify the statistics of the main...

This study investigated the effects of two alternative substrates (wood mulch and zeolite) on the performance of three laboratory-scale hybrid wetland systems that had identical system components and configurations. Each system consisted of a vertical flow (VF) wetland column, followed by a horizontal flow (HF) column and a vertical flow (VF) colum...

Biofiltration systems are a recommended and increasingly popular technology for stormwater management; however there is a general lack of performance data for these systems, particularly at the field scale. The objective of this study was to investigate the hydrologic and pollutant removal performance of three field-scale biofiltration systems in t...

The pollutant removal performance of three separate stormwater biofiltration systems in two different climates was assessed. At one of the sites, rain events were simulated, while actual runoff events were monitored at the other two sites. In all cases, concentrations of total suspended solids (TSS), copper, lead and zinc were effectively and relia...

This paper reviews the progress of the the Facility for Advancing Water Biofiltration (FAWB) towards proving the concept of biofiltration to improve the quality of stormwater, focusing primarily on bioretention systems. Institutional factors that influence their adoption and management are also reviewed. The laboratory and field-scale testing progr...

The degradation of aquatic ecosystems due to hydrologic and water quality impacts of urbanization, combined with increasing water scarcity, has generated increasing interest in the harvesting of urban storm water. This paper reviews the rationale for integrated storm water treatment and harvesting and synthesizes recent advances and trends and know...

Stormwater runoff from urban areas has multiple negative hydrologic and ecological impacts for receiving waters. Fine media stormwater filtration systems have the potential to mitigate these effects, through flow attenuation and pollutant removal. This work provides an overall assessment of the hydraulic and pollutant removal behavior of sand- and...

Stormwater biofiltration systems are an increasingly popular treatment technology and are being installed in all major cities in Australia. Their concept is very simple and easily implemented in all urban forms. Unfortunately, we know very little about the performance of biofiltration systems, particularly with respect to their long-term hydraulic...

Biofiltration systems are an increasingly popular low-energy treatment technology for improved stormwater management. However, while extensive laboratory testing has demonstrated their capacity for effective removal of a wide range of stormwater pollutants, field-scale performance data is limited. Three stormwater biofiltration systems of varying s...

Stormwater infiltration systems are widely used to address the flow and water quality impacts of urbanization. However, their pollutant removal performance is uncertain, with respect to varying filter depth, and over time. Seven simulation experiments were conducted on a laboratory-scale gravel infiltration system to test the pollutant removal unde...

As the concept of integrated urban water management is incorporated into the practice of urban water servicing, new options, such as stormwater harvesting, which can have multiple benefits, are of increasing interest. The multi-functional benefits of stormwater harvesting include the potential to enhance urban stream health through improvements to...

Stormwater reuse is increasing in popularity as a technique for overcoming water shortages in urban Australia. However, technology for the reliable treatment of stormwater for reuse is still not fully developed. This paper presents the first steps in refining biofilters for stormwater reuse. Six different filter media were selected, to target speci...

Biofiltration systems are an effective stormwater treatment technology. However, their robustness is yet to be tested, particularly their performance following extended dry periods. The hydraulic and treatment performance of five different non-vegetated, soil-based filters under varying periods of inundation and drying was assessed. The infiltratio...

Biofiltration systems are being installed on an ever-increasing scale, both for stormwater quality improvement and as a component of stormwater reuse systems. However, there is currently a general lack of knowledge regarding their design, implementation and performance. This paper reports on the issues encountered and lessons learnt during the inst...

RESUME Les biofiltres sont soumis à de hauts niveaux de variabilité dans leur fréquence et durée de mise en eau et dans les périodes de temps sec entre ces mises en eau. Les effets des périodes de mouillage et de séchage sur la performance de cinq filtres non végétalisés ont été testé en laboratoire où ils ont été soumis à différentes fréquences d'...

With the use of water approaching, and in some cases exceeding, the limits of sustainability in many locations, there is an increasing recognition of the need to utilise stormwater for non-potable requirements, thus reducing the demand on potable sources. This paper presents a review of Australian stormwater treatment and recycling practices as wel...

Improved urban water management in Australia is of national importance. Water resources are stretched and urban runoff is a recognized leading cause of degradation of urban waterways. Stormwater recycling is an option that can contribute to easing these problems. Biofilters are effective structural stormwater pollution control measures with the pot...

Effective water quality management of streams in urbanized basins requires identification of the elements of urbanization that contribute most to pollutant concentrations and loads. Drainage connection (the proportion of impervious area directly connected to streams by pipes or lined drains) is proposed as a variable explaining variance in the gene...

1. Urbanisation is an important cause of eutrophication in waters draining urban areas. We determined whether benthic algal biomass in small streams draining urban areas was explained primarily by small-scale factors (benthic light, substratum type and nutrient concentrations) within a stream, or by catchment-scale variables that incorporate the in...

The aim of this research was to develop an inventory of technologies for the collection, treatment, storage, and distribution of general urban stormwater runoff (runoff from all types of urban areas, including roads, car parks etc.) and, where current knowledge allows, provide interim guidance on stormwater re-use implementation. An extensive revie...