Optimizing native vegetation establishment in urban soils: Assessing the impacts of organic amendments on specific growth parameters.

Following soil disturbances, establishing healthy roadside vegetation can reduce surface water runoff, improve soil quality, decrease erosion, and enhance landscape aesthetics. This study explores the use of organic soil amendments (OAs) as alternatives to conventional vegetation growth approaches, aiming to provide optimal compost mixing ratios for poor soils, and clarify guidelines for OAs' use in roadside projects. Three sandy loam soils and one loam soil were chosen for the study.

Using organic amendments in disturbed soil to enhance soil organic matter, nutrient content and turfgrass establishment.

Disturbed soils, including manufactured topsoils, often lack physical and chemical properties conducive to vegetation establishment. As a result, efforts to stabilize disturbed soils with vegetation are susceptible to failure. Urban organic waste products such as wood mulch, composted leaf and yard waste, and biosolids are widely distributed as organic amendments that enhance sustainability and plant establishment.

Nutrient transport, shear strength and hydraulic characteristics of topsoils amended with mulch, compost and biosolids.

Anthropogenic disturbance of soils can disrupt soil structure, diminish fertility, alter soil chemical properties, and cause erosion. Current remediation practices involve amending degraded urban topsoils lacking in organic matter and nutrition with organic amendments (OA) to enhance vegetative growth. However, the impact of OAs on water quality and structural properties at rates that meet common topsoil organic matter specifications need to be studied and understood.

Interactions of particulate- and dissolved-phase heavy metals in a mature stormwater bioretention cell.

Bioretention is an increasingly common stormwater control measure (SCM) for mitigation of stormwater quantity and quality. Studies from lab to field scale have shown successful removal of total metals from stormwater, especially Cu and Zn which are ubiquitous in the urban environment yet detrimental to aquatic ecosystems. While bioretention effectively removes particulate matter and particulate bound (PB) contaminants, removal performance of dissolved metals has been neglected in field studies.

Considerations for evaluating innovative stormwater treatment media for removal of dissolved contaminants of concern with focus on biochar.

Stormwater from complex land uses is an important contributor of contaminants of concern (COCs) such as polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), Copper, and Zinc to receiving water bodies. A large portion of these COCs bind to particulate matter in stormwater, which can be removed through filtration by traditional media. However, the remaining dissolved COCs can be significant and require special attention such as engineered treatment measures and media.

Removal of stormwater dissolved organic nitrogen through biotransformation using activated carbon.

Conventional bioretention systems are not effectively designed to remove stormwater dissolved organic nitrogen (DON). Biotransformation study on five organic nitrogenous compounds with different values for adsorption on coal activated carbon (AC) and bioavailability revealed that adsorption is a greater controlling factor for ammonification than bioavailability. This study also showed three apparent benefits: enhancement of the ammonification rate, ammonification of the bio-recalcitrant organic nitrogenous compounds, for example, pyrrole, and bio-regeneration of the adsorbent (coal AC).

Unconventional microbial mechanisms for the key factors influencing inorganic nitrogen removal in stormwater bioretention columns.

Bioretention systems are environmentally friendly measures to control the amount of water and pollutants in urban stormwater runoff, and their treatment performance for inorganic N strongly depends on various microbial processes. However, microbial responses to variations of N mass reduction in bioretention systems are complex and poorly understood, which is not conducive to management designs. In the present study, a series of bioretention columns were established to monitor their fate performance for inorganic N (NHand NO) by using different configurations and by dosing with simulated stormwater events.

Chemical characterization of urban stormwater: Traditional and emerging contaminants.

Increases in urbanization have led to increased stormwater runoff and mobilization of pollutants from urban watersheds. Discharge of these pollutants often leads to contamination of receiving water bodies. Chemical characterization of urban stormwater is necessary to gain deeper insights into the ecological impacts of urban runoff and to evaluate parameters that influence possible treatment technologies.

Biological nitrogen removal from stormwater in bioretention cells: a critical review.

Excess nitrogen in stormwater degrades surface water quality eutrophication and related processes. Bioretention has been recognized as a highly effective low-impact development (LID) technology for the management of high runoff volumes and reduction of nitrogen (N) pollutants through various mechanisms. This paper provides a comprehensive and critical review of recent developments on the biological N removal processes occurring in bioretention systems.

Characterizing laboratory-scale clinoptilolite bio-columns for removal and nitrification of ammoniacal nitrogen in simulated stormwater.

Due to the diverse speciation and biochemical characteristics of nitrogen in urban runoff, excess nitrogen continues to be a major source of eutrophication in receiving waters. The performance of a nitrifying-sorptive Clinoptilolite (ZT) was examined for use in a media-based stormwater control measure (SCM) for ammonium removal. Results suggested that columns operated under continuous feed showed more nitrification as the media approached ammonium exhaustion.

Bioretention systems for stormwater management: Recent advances and future prospects.

Bioretention is a popular stormwater management strategy that is often utilized in urban environments to combat water quality and hydrological impacts of stormwater. This goal is achieved by selective designing of a system, which consists of suitable vegetation at the top planted on an engineered media with drainage system and possible underdrain at the bottom. Bibliometric analysis on bioretention studies indicates that most of the original research contributions are derived from a few countries and selected research groups.

Activated carbon column adsorption of compounds that mimic urban stormwater dissolved organic nitrogen.

Nutrients mobilized by stormwater can exacerbate eutrophication in receiving waters. While bioretention systems are increasingly employed to improve stormwater quality, they do not normally incorporate design attributes for removal of dissolved organic nitrogen (DON). Thus, the current study concentrated on continuous column adsorption of stormwater DON using a media mixture of coal activated carbon and quartz sand.

Evaluation of an enhanced treatment media and permeable pavement base to remove stormwater nitrogen, phosphorus, and metals under simulated rainfall.

An enhanced stormwater treatment media, developed previously by the authors, was shown to effectively retain dissolved phosphorus (DP) and total Cu and Zn under simulated rainfall. The media comprises expanded shale aggregate, aluminum-based water treatment residual (WTR), and a psyllium-based binder. A 5-cm layer of media was installed as a permeable pavement base layer in a laboratory mesocosm and subjected to rainfall simulations using synthetic stormwater.

Impact of vegetation selection on nitrogen and phosphorus processing in bioretention containers.

A year-long bioretention container study in Maryland, USA, measured the relationship between three plant species (Eutrochium dubium, Iris versicolor, and Juncus effusus) and N ( , , , total nitrogen [TN], total dissolved nitrogen [TDN], dissolved organic nitrogen, particulate organic nitrogen [PON]) and total phosphorus (TP) removal from synthetic stormwater. Statistically significant removal was only found for and TP. Plant-independent removal occurred 9 months after planting, and then changed to removal only by the least-densely planted Juncus treatment.

Polychlorinated biphenyls in stormwater sediments: Relationships with land use and particle characteristics.

Polychlorinated biphenyls (PCBs) are classified as persistent organic pollutants (POPs). Concentrations of 209 PCB congeners as well as profiles of the ten homologues were determined in stormwater sediments collected from various (primarily roadway) sites with different land use. The total PCB concentrations ranged from 8.

Ettringite and monosulfate formation to reduce alkalinity in reactions of alum-based water treatment residual with steel slag.

Aged steel slag has a potential use as a highly durable aggregate in roadway construction; however, its high capacity for creating alkaline leachates (pH > 12.4) poses a severe environmental risk. In batch and column leach tests, 10% alum-based water treatment residual (WTR) addition to aged steel slag resulted in a 67% decrease in acid neutralizing capacity of steel slag and leachate alkalinity, but this alkalinity mitigation effect was accompanied with markedly increases in dissolved Al concentrations in the leachates (<4.

Understanding urban stormwater denitrification in bioretention internal water storage zones.

Conventional free-draining bioretention systems promote nitrate production and continual leaching to receiving waters. In this study, laboratory tests demonstrated the efficacy of an internal water storage zone (IWSZ) to target nitrate removal via denitrification. Experimental results confirmed that the carbon substrate characteristics (Willow Oak woodchip media) and the hydraulic retention time of nitrified stormwater affected nitrate removal performance.

Ammonium Removal from Synthetic Stormwater using Clinoptilolite and Hydroaluminosilicate Columns.

  Ammonium can enter stormwater control measures (SCMs) with the influent, but is also the intermediate product between organic nitrogen and nitrate, and it is important to retain and treat ammonium within the SCM. In this study the use of aluminosilicate aggregates (CA) and clinoptilolite zeolite (ZT) was investigated under SCM (column) conditions. ZT was found to have the highest capacity (0.

Adsorption of Compounds that Mimic Urban Stormwater Dissolved Organic Nitrogen.

  Stormwater runoff carrying nitrogen can accelerate eutrophication. Bioretention facilities are among low impact development systems which are commonly used to manage urban stormwater quality and quantity. They are, however, not designed to remove dissolved organic nitrogen (DON) and may become a net DON exporter.

A unified look at phosphorus treatment using bioretention.

Phosphorus (P) is a water pollutant of significant concern as it limits the productivity of most freshwater systems, which can undergo eutrophication under heavy phosphorus inputs. Bioretention has shown great potential for stormwater quantity and quality control. However, phosphorus removal has been inconsistent in bioretention systems, with phosphorus leaching observed in some systems.

Performance of a 'Transitioned' Infiltration Basin Part 2: Nitrogen and Phosphorus Removals.

Infiltration basins have been widely used for stormwater runoff management. However, their longevity could be compromised over time, up to the point of operational failure. This research study showed that a 'failed' infiltration basin can 'transition' into a wetpond/wetland-like practice and provide water quality benefits.

Performance of a 'Transitioned' Infiltration Basin Part 1: TSS, Metals, and Chloride Removals.

The water quality performance of a 'failed' stormwater infiltration basin that has 'transitioned' to a wetpond/wetland has been evaluated over a three-year period. Total suspended solids, heavy metals, and chloride in highway runoff and discharge from the transitioned basin were measured during 38 storm events. The transitioned basin provided significant reductions in TSS Event Mean Concentrations (EMCs) and mass in the runoff.

Growth and Cadmium Phytoextraction by Swiss Chard, Maize, Rice, Noccaea caerulescens, and Alyssum murale in Ph Adjusted Biosolids Amended Soils.

Past applications of biosolids to soils at some locations added higher Cd levels than presently permitted. Cadmium phytoextraction would alleviate current land use constraints. Unamended farm soil, and biosolids amended farm and mine soils were obtained from a Fulton Co.

Urban stormwater runoff nitrogen composition and fate in bioretention systems.

Multiple chemical forms of nitrogen in urban stormwater make its management challenging. Sixteen storm events were monitored and analyzed for total nitrogen (TN), particulate organic nitrogen (PON), nitrate (NO3-N), nitrite (NO2-N), ammonium (NH3-N), and dissolved organic nitrogen (DON) in stormwater runoff and in treated discharge through a conventional bioretention cell. Influent PON can be effectively removed via bioretention sedimentation/filtration, NH3-N by ion exchange/sorption, and NO2-N by oxidation.