Peat as Substrate for Small-Scale Constructed Wetlands Polishing Secondary Effluents from Municipal Wastewater Treatment Plant

Jin, Meng; Carlos, Jacob; McConnell, Rachel; Hall, Geof; Champagne, Pascale

doi:10.3390/w9120928

Cited by 14 publications

(12 citation statements)

References 46 publications

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“…The values were within nitrate removal rates found for woodchips (ranging from 0.7 to 5.0 g/(m 2 •day) NO 3 -N) [7,34]. The obtained nitrate removal efficiency is higher than that reported for coco-peat (54%) and organic soils (20%) [16,35]. The reason probably was that lower oxygen concentrations (lower redox potential values) were observed in this study, especially at the bottom of the container.…”

Section: Nitrate Removal Rate and Efficiencysupporting

confidence: 80%

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Nitrate Attenuation in Degraded Peat Soil-Based Constructed Wetlands

Kleimeier

Liu

Rezanezhad

et al. 2018

Water

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Constructed wetlands (CWs) provide favorable conditions for removing nitrate from polluted agricultural runoff via heterotrophic denitrification. Although the general operability of CWs has been shown in previous studies, the suitability of peat soils as a bed medium for a vertical flow through a system for nitrate attenuation has not been proven to date. In this study, a mesocosm experiment was conducted under continuous flow with conditions aiming to quantify nitrate (NO 3 −) removal efficiency in degraded peat soils. Input solution of NO 3 − was supplied at three different concentrations (65, 100, and 150 mg/L). Pore water samples were collected at different depths and analyzed for NO 3 − , pH, and dissolved N 2 O concentrations. The redox potential (Eh) was registered at different depths. The results showed that the median NO 3-N removal rate was 1.20 g/(m 2 •day) and the median removal efficiency was calculated as 63.5%. The nitrate removal efficiency was affected by the NO 3 − supply load, flow rate, and environmental boundary conditions. A higher NO 3 − removal efficiency was observed at an input NO 3 − concentration of 100 mg/L, a lower flow rate, and higher temperature. The results of pore water pH and NO 3 − and N 2 O levels from the bottom of the mesocosm suggest that N 2 is the dominant denitrification product. Thus, degraded peat soils showed the potential to serve as a substrate for the clean-up of nitrate-laden agricultural runoff.

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Section: Nitrate Removal Rate and Efficiencysupporting

confidence: 80%

“…Thus, peat soils could potentially serve as denitrification beds for CWs. However, there are few studies about the performance of peat soils as denitrification bed materials [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Nitrate Attenuation in Degraded Peat Soil-Based Constructed Wetlands

Kleimeier

Liu

Rezanezhad

et al. 2018

Water

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“…Wetlands are useful for controlling pollution related to phosphorus (P) [1][2][3][4], as it may be taken up by vegetation before being washed into lakes or rivers. Much research is concerned with the effects of P removal by plants in wetlands [1,5,6], especially with the control of non-point source pollution [7].…”

Section: Introductionmentioning

confidence: 99%

Phosphorus Solubilizing and Releasing Bacteria Screening from the Rhizosphere in a Natural Wetland

Cao

Liu

et al. 2018

Water

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Inorganic phosphorus (P)-solubilizing bacteria (IPSB) and organic P-mineralizing bacteria (OPMB) were isolated from bacteria that were first extracted from the rhizosphere soil of a natural wetland and then grown on either tricalcium phosphate or lecithin medium. The solubilizing of inorganic P was the major contribution to P availability, since the isolated bacteria released much more available P from inorganic tricalcium phosphate than lecithin. IPSB No. 5 had the highest P release rate, that is, 0.53 mg·L −1 ·h −1 in 96 h, and R10 s release rate was 0.52 mg·L −1 ·h −1 in 10 days. The bacteria were identified as Pseudomonas sp. and Pseudomonas knackmussii, respectively. R10 released as much as 125.88 mg·L −1 dissolved P from tricalcium phosphate medium, while R4 released the most dissolved P from organic P medium among the isolates, with a concentration of 1.88 mg·L −1 and a releasing rate of 0.0078 mg·L −1 ·h −1 in ten days. P releasing increased with a pH decrease only when it was from inorganic P, not organic lecithin, and there was no significant correlation between the culture pH and P solubilizing. High-throughput sequencing analysis revealed that the dominant phylum in the studied wetland rhizosphere consisted of Acidobacteria, Proteobacteria, Bacteroidetes and Chloroflexi, accounting for 34.9%, 34.2%, 8.8% and 4.8%, respectively.

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“…Special purpose acquisition companies have been used as a modern financing structure since the 1990s in the United States of America and are gaining popularity in other countries, such as Australia, Austria, Canada, Germany, Malaysia, the Netherlands, New Zealand, South Africa, South Korea and the United Kingdom (Murray 2017;Shachmurove & Vulanovic 2015). However, limited research has been carried out to date on SPACs internationally and especially in South Africa (Dimitrova 2017;Kolb & Tykvová 2016;Riva & Provasi 2019;Shachmurove & Vulanovic 2015). Yochanan and Milos (2018) have summarised the available literature on SPACs and have found the legal and financial literature, explained SPACs' historical development, institutional characteristics and structure well.…”

Section: Literature Reviewmentioning

confidence: 99%

“…The study by Dimitrova (2017) focuses on the deal structures. According to Dimitrova (2017), the popularity of SPAC transactions is likely to continue because of the recent trend in the private equity industry towards alternative, more flexible structures of fund-raising.…”

Section: Literature Reviewmentioning

confidence: 99%

Special purpose acquisition companies as a vehicle for providing venture capital to small and medium size enterprise

Marx

Mohammadali-Haji

Botha

et al. 2021

Journal of Economic and Financial Sciences

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Orientation: The South African economy is currently at one of its lowest points in several decades, with low economic growth, coronavirus challenges and unemployment being at an all-time high. This is further aggravated by the many challenges the economy faces, such as the lack of public sector programs to stimulate sustainable growth and a private sector mind-set that lacks business confidence and investment.Motivation of study: A SPAC is an innovative financial structure that aims to raise funds in capital markets with the purpose of acquiring an unknown exiting company, using the funds as finance, within a limited time period. Special purpose SPACs focusing on SMEs with additional criteria and incentives might prove to be a valuable vehicle that provides funding to stimulate economic growth, kick start the second economy and erode unemployment in South Africa.Research purpose: The objective of this article was to provide an overview of a special purpose acquisition company (SPAC) as a vehicle to fund future business operations and, further, to explore the opportunities that it may provide to the South African economy to stimulate growth in the second economy and small and medium-sized enterprise (SME) sector.Research approach/ design and method: This article follows a qualitative research design with an exploratory approach.Findings and contribution: Research on SPACs internationally and in South Africa is scarce and this article makes a significant contribution to the existing body of knowledge. The findings indicate that the financial measures show underperformance of SPACs relative to some traditional financial measures.Practical implications: Non-financial considerations are important in considering the value that SPACs can bring to the ailing South African economy. Special purpose acquisition companies also provide opportunities to those informal sectors, which would never be able to get access to funding and formal markets in other ways.

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Peat as Substrate for Small-Scale Constructed Wetlands Polishing Secondary Effluents from Municipal Wastewater Treatment Plant

Cited by 14 publications

References 46 publications

Nitrate Attenuation in Degraded Peat Soil-Based Constructed Wetlands

Nitrate Attenuation in Degraded Peat Soil-Based Constructed Wetlands

Phosphorus Solubilizing and Releasing Bacteria Screening from the Rhizosphere in a Natural Wetland

Special purpose acquisition companies as a vehicle for providing venture capital to small and medium size enterprise

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