Fate of wastewater trace organic chemicals in vegetated biofiltration systems.

Vegetated biofiltration system (VBS) is an effective green technology for urban stormwater and greywater treatment. However, VBS is yet to be optimised for effective treatment of wastewater, particularly if it contains trace organic chemicals (TrOCs). The effect of plant species has not been addressed under TrOC wastewater loading.

Real time control of stormwater biofilters improves the removal of organic chemicals.

Biofilters are among the most popular nature-based systems for treating stormwater and delivering multiple environmental benefits. However, as a passive system, their performance tends to be inconsistent in removing emerging organic contaminants produced by anthropogenic activities that can be persistent, mobile, and toxic. Thus, in this study, real time control (RTC) of stormwater biofilters is introduced to enhance the removal of a diverse range of organic chemicals.

Impact of electrochemically generated iron on the performance of an anaerobic wastewater treatment process.

Anaerobic treatment of domestic wastewater has the advantages of lower biomass yield, lower energy demand and higher energy recover over the conventional aerobic treatment process. However, the anaerobic process has the inherent issues of excessive phosphate and sulfide in effluent and superfluous HS and CO in biogas. An electrochemical method allowing for in-situ generation of Fe in the anode and hydroxide ion (OH) and H in the cathode was proposed to overcome the challenges simultaneously.

Nitrification potential of daily-watered biofiltration designs for high ammonium wastewater treatment.

The vegetated biofiltration systems (VBS), also known as bioretentions or rain gardens, are well-established technology for treatment of urban stormwater and recently greywater, offering multiple benefits to urban environments. However, the impact of high ammonium strength wastewater (60 mg/L) on the nitrification process in these systems is not well understood. Hence, a laboratory-based column study was conducted to uncover dominant nitrification mechanisms, based on the learnings from similar onsite wastewater treatment systems.

Electrochemical iron production to enhance anaerobic membrane treatment of wastewater.

Although iron salts such as iron(III) chloride (FeCl) have widespread application in wastewater treatment, safety concerns limit their use, due to the corrosive nature of concentrated solutions. This study demonstrates that local, electrochemical generation of iron is a viable alternative to the use of iron salts. Three laboratory systems with anaerobic membrane processes were set up to treat real wastewater; two systems used the production of either in-situ or ex-situ electrochemical iron (as Fe and Fe(Fe)O, respectively), while the other system served as a control.

Community values on governing urban water nature-based solutions in Sydney, Australia.

Since the needs and expectations of communities towards their urban environments often vary, landscape management strategies can often be prone to fail in the absence of social considerations. It is therefore incumbent on policy-makers to investigate and attempt to reconcile diverse community perceptions toward the natural and built environment for more equitable governance. This is of particular interest when planning and managing nature-based solutions (NBS) for river protection.

Effect of filling ratio and backwash on performance of a continuous-flow SPD reactor packed with PCL as carbon source.

In this study, three up-flow fixed-bed bioreactors, named as A, B, and C, packed with polycaprolactone (PCL) under different filling ratios (31%, 62%, and 93%, respectively), were investigated over a long period (96 days). During the stable period, the mean effluent concentrations in reactors A, B, and C were 1.35 ± 0.

The effect of intermittent drying and wetting stormwater cycles on the nutrient removal performances of two vegetated biofiltration designs.

Vegetated biofiltration systems (biofilters) are now a well-established technology for treatment of urban stormwater, typically showing high nutrient uptake. However, the impact of high temporal variability of rainfall events (further exacerbated by climate change) on nitrogen and phosphorus removal processes, within different biofiltration designs, is still unknown. Hence, a laboratory-based study was conducted to uncover mechanisms behind nutrient removal in biofilters across different drying and wetting regimes.

Effective treatment of greywater via green wall biofiltration and electrochemical disinfection.

Low energy and cost solutions are needed to combat raising water needs in urbanised areas and produce high quality recycled water. In this study, we investigated key processes that drive a unique greywater treatment train consisting of a passive green wall biofiltration system followed by disinfection using a Boron-doped diamond (BDD) electrode with a solid polymer electrolyte (SPE). In both systems, the treatment was performed without any additional chemicals and pollutants of concern were monitored for process evaluation.

Green wall height and design optimisation for effective greywater pollution treatment and reuse.

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 treatment, and how tall should the system be to assure adequate treatment. This paper reports on (i) a long-term pollutant removal comparison study of two typical green wall configurations: pot and block designs, and (ii) a short-term profile study exploring pollutant retention at different heights of a three-level green wall, across different plant species.

Assessing water retention and correlation to climate conditions of five plant species in greywater treating green walls.

Green walls are becoming a popular infrastructure choice in densely built urban environments, due to their multiple benefits. However, high and vastly variable water requirements of these systems are preventing their further widespread. Only a small number of studies have investigated water needs of green walls, even though this can help to design more optimal systems with increased benefits.