Nature based solutions for removal of steroid estrogens in wastewater.

Estrogens are a growing problem in wastewater discharges because they are continuously entering the environment and are biologically active at extremely low concentrations. Their effects on wildlife were first identified several decades before, but the environmental limits and the remedial measures are still not completely elucidated. Most conventional treatment processes were not designed with sufficiently long retention times to effectively remove estrogens.

Quality of cellulose and biostimulant extracts from Oedogonium calcareum cultivated during primary wastewater treatment.

A practical two-product cascading biorefinery was developed to extract a biostimulant and cellulose from the freshwater filamentous macroalga Oedogonium calcareum grown while treating primary wastewater. Biostimulant production provides a valuable extract with production of disinfected residual biomass for further product development. Both Escherichia coli and F-specific RNA bacteriophage, indicators of human pathogens contamination, were absent from the residual biomass.

Elucidating phosphorus removal dynamics in a denitrifying woodchip bioreactor.

Denitrifying woodchip bioreactors (DBRs) are an established nitrate mitigation technology, but uncertainty remains on their viability for phosphorus (P) removal due to inconsistent source-sink behaviour in field trials. We investigated whether iron (Fe) redox cycling could be the missing link needed to explain P dynamics in these systems. A pilot-scale DBR (Aotearoa New Zealand) was monitored for the first two drainage seasons (2017-2018), with supplemental in-field measurements of reduced solutes (Fe, HS/HS) and their conjugate oxidised species (Fe/SO) made in 2021 to constrain within-reactor redox gradients.

Effects of operational parameters on the performance of unialgal Oedogonium sp. filamentous algae nutrient scrubbers under controlled environmental conditions.

Filamentous algae nutrient scrubber (FANS) operating parameters can strongly influence algal biomass productivity and nutrient removal. However, few studies to date have investigated the effects of FANS operating parameters such as initial standing crop, harvesting frequency and influent flow rate on biomass productivity and nutrient removal performance, especially for FANS that cultivate a single species of algae. Therefore, the overall aim of this study was to investigate how operating parameters affect the biomass productivity and nutrient removal performance of Oedogonium sp.

Effect of algal contact time and horizontal water velocity on the performance of Filamentous Algal Nutrient Scrubbers (FANS).

We investigated the effect of algal contact time (ACT) and horizontal water velocity (HWV) on the performance of pilot-scale Filamentous Algae Nutrient Scrubbers (FANS) treating river water during the NZ summer. The FANS floways were seeded with a mixture of four New Zealand native filamentous algal species (Oedogonium sp., Cladophora sp.

Comparison of faecal indicator and viral pathogen light and dark disinfection mechanisms in wastewater treatment pond mesocosms.

This study compared light and dark disinfection of faecal bacteria/viral indicator organisms (E. coli and MS2 (fRNA) bacteriophage) and human viruses (Echovirus and Norovirus) in Wastewater Treatment Pond (WTP) mesocosms. Stirred pond mesocosms were operated in either outdoor sunlight-exposed or laboratory dark conditions in two experiments during the austral summer.

Seasonal performance of a full-scale wastewater treatment enhanced pond system.

Enhanced pond systems (EPS) consist of a series of ponds that have been designed to work in synergy to provide both cost-effective enhanced wastewater treatment and resource recovery, in the form of algal biomass, for beneficial reuse. Due to the limited number of full-scale EPS systems worldwide, our understanding of factors governing both enhanced wastewater treatment and resource recovery is limited. This paper investigates the seasonal performance of a full-scale municipal wastewater EPS with respect to nutrient removal from the liquid fraction, microalgal biomass production and subsequent removal through the system.

Environmental drivers that influence microalgal species in fullscale wastewater treatment high rate algal ponds.

In the last decade, studies have focused on identifying the most suitable microalgal species for coupled high rate algal pond (HRAP) wastewater treatment and resource recovery. However, one of the challenges facing outdoor HRAP systems is maintaining microalgal species dominance. By increasing our understanding of the environmental drivers of microalgal community composition within the HRAP environment, it may be possible to manipulate the system in such a way to favour the growth of desirable species.

Wastewater treatment high rate algal pond biomass for bio-crude oil production.

This study investigates the production potential of bio-crude from wastewater treatment high rate algal pond (WWT HRAP) biomass in terms of yield, elemental/chemical composition and higher heating value (HHV). Hydrothermal liquefaction (HTL) of the biomass slurry (2.2wt% solid content, 19.

Biodiesel production potential of wastewater treatment high rate algal pond biomass.

This study investigates the year-round production potential and quality of biodiesel from wastewater treatment high rate algal pond (WWT HRAP) biomass and how it is affected by CO addition to the culture. The mean monthly pond biomass and lipid productivities varied between 2.0±0.

Winter-time CO2 addition in high rate algal mesocosms for enhanced microalgal performance.

Carbon limitation in domestic wastewater high rate algal ponds is thought to constrain microalgal photo-physiology and productivity and CO2 augmentation is often used to overcome this limitation in summer. However, the implications of carbon limitation during winter are poorly understood. This paper investigates the effects of 0.

Algal recycling enhances algal productivity and settleability in Pediastrum boryanum pure cultures.

Recycling a portion of gravity harvested algae (i.e. algae and associated bacteria biomass) has been shown to improve both algal biomass productivity and harvest efficiency by maintaining the dominance of a rapidly-settleable colonial alga, Pediastrum boryanum in both pilot-scale wastewater treatment High Rate Algal Ponds (HRAP) and outdoor mesocosms.

Modifying the high rate algal pond light environment and its effects on light absorption and photosynthesis.

The combined use of high rate algal ponds (HRAPs) for wastewater treatment and commercial algal production is considered to be an economically viable option. However, microalgal photosynthesis and biomass productivity is constrained in HRAPs due to light limitation. This paper investigates how the light climate in the HRAP can be modified through changes in pond depth, hydraulic retention time (HRT) and light/dark turnover rate and how this impacts light absorption and utilisation by the microalgae.

The effects of CO₂ addition along a pH gradient on wastewater microalgal photo-physiology, biomass production and nutrient removal.

Carbon limitation in domestic wastewater high rate algal ponds is thought to constrain microalgal photo-physiology and productivity, particularly in summer. This paper investigates the effects of CO₂ addition along a pH gradient on the performance of wastewater microalgae in high rate algal mesocosms. Performance was measured in terms of light absorption, electron transport rate, photosynthetic efficiency, biomass production and nutrient removal efficiency.

Wastewater treatment high rate algal ponds (WWT HRAP) for low-cost biofuel production.

Growing energy demand and water consumption have increased concerns about energy security and efficient wastewater treatment and reuse. Wastewater treatment high rate algal ponds (WWT HRAPs) are a promising technology that could help solve these challenges concurrently where climate is favorable. WWT HRAPs have great potential for biofuel production as a by-product of WWT, since the costs of algal cultivation and harvest for biofuel production are covered by the wastewater treatment function.

Enhancing microalgal photosynthesis and productivity in wastewater treatment high rate algal ponds for biofuel production.

With microalgal biofuels currently receiving much attention, there has been renewed interest in the combined use of high rate algal ponds (HRAP) for wastewater treatment and biofuel production. This combined use of HRAPs is considered to be an economically feasible option for biofuel production, however, increased microalgal productivity and nutrient removal together with reduced capital costs are needed before it can be commercially viable. Despite HRAPs being an established technology, microalgal photosynthesis and productivity is still limited in these ponds and is well below the theoretical maximum.

Effects of two different nutrient loads on microalgal production, nutrient removal and photosynthetic efficiency in pilot-scale wastewater high rate algal ponds.

When wastewater treatment high rate algal ponds (HRAP) are coupled with resource recovery processes, such as biofuel production, short hydraulic retention times (HRTs) are often favoured to increase the microalgal biomass productivity. However, short HRT can result in increased nutrient load to the HRAP which may negatively impact on the performance of the microalgae. This paper investigate the effects of high (NH4-N mean concentration 39.

Wastewater microalgal production, nutrient removal and physiological adaptation in response to changes in mixing frequency.

Laminar flows are a common problem in high rate algal ponds (HRAP) due to their long channels and gentle mixing by a single paddlewheel. Sustained laminar flows may modify the amount of light microalgal cells are exposed to, increase the boundary layer between the cell and the environment and increase settling out of cells onto the pond bottom. To date, there has been little focus on the effects of the time between mixing events (frequency of mixing) on the performance of microalgae in wastewater treatment HRAPs.

Investigating the life-cycle and growth rate of Pediastrum boryanum and the implications for wastewater treatment high rate algal ponds.

The colonial alga Pediastrum boryanum has beneficial characteristics for wastewater treatment High Rate Algal Ponds (HRAP) including high biomass productivity and settleability. Our previous work has shown that these characteristics are enhanced when a portion of gravity harvested algae is recycled back to the pond. To help understand the mechanisms behind the improved performance of P.

Influence of temperature and pretreatments on the anaerobic digestion of wastewater grown microalgae in a laboratory-scale accumulating-volume reactor.

This laboratory-scale study investigated the performance of a low-cost anaerobic digester for microalgae. Low (∼2%) solids content wastewater-grown microalgal biomass (MB) was digested in an unmixed, accumulating-volume reactor (AVR) with solid and liquid separation that enabled a long solids retention time. AVRs (2 or 20 L) were operated at 20 °C, 37 °C or ambient temperature (8-21 °C), and the influence of two pretreatments - low-temperature thermal (50-57 °C) and freeze-thaw - on algal digestion were studied.

Increased pond depth improves algal productivity and nutrient removal in wastewater treatment high rate algal ponds.

Depth has been widely recognised as a crucial operational feature of a high rate algal pond (HRAP) as it modifies the amount of light and frequency at which microalgal cells are exposed to optimal light. To date, there has been little focus on the optimisation of microalgal performance in wastewater treatment HRAPs with respect to depth, with advice ranging from as shallow as possible to 100 cm deep. This paper investigates the seasonal performance of microalgae in wastewater treatment HRAPs operated at three different depths (200, 300 and 400 mm).

Modification, calibration and verification of the IWA River Water Quality Model to simulate a pilot-scale high rate algal pond.

We implemented the IWA River Water Quality Model No. 1 (Reichert et al., 2001.

Universal temperature model for shallow algal ponds provides improved accuracy.

While temperature is fundamental to the design and optimal operation of shallow algal ponds, there is currently no temperature model universally applicable to these systems. This paper presents a model valid for any opaque water body of uniform temperature profile. This new universal model was tested against 1 year of experimental data collected from a wastewater treatment high rate algal pond.