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Andy Shilton

Bio: Andy Shilton is an academic researcher from Massey University. The author has contributed to research in topics: Phosphorus & Wastewater. The author has an hindex of 31, co-authored 69 publications receiving 4331 citations. Previous affiliations of Andy Shilton include Nanyang Technological University & National Institute of Water and Atmospheric Research.


Papers
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Journal ArticleDOI
TL;DR: The critical parameters that limit algal cultivation, production and harvest are reviewed and practical options that may enhance the net harvestable algal production from wastewater treatment HRAPs including CO(2) addition, species control, control of grazers and parasites and bioflocculation are discussed.

989 citations

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TL;DR: It is proposed that Type II models currently offer the best compromise between accuracy and practicability for full scale engineering application and the recommended approach is uncoupled models.

337 citations

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TL;DR: The results of this work show that AISP is believed to be a form of phosphorus storage and ASP is involved in metabolism however, the results show that ASP can also act as a short term form of phosphate storage.

306 citations

Journal ArticleDOI
TL;DR: The variability in the phosphorus content of the microalgal biomass shows that with this new understanding of the luxury uptake mechanism there is the potential to optimize WSP for biological phosphorus removal.
Abstract: Phosphorus removal in waste stabilization ponds (WSP) is highly variable, but the reasons for this are not well understood. Luxury uptake of phosphorus by microalgae has been studied in natural systems such as lakes but not under the conditions found in WSP. This work reports on the effects of phosphate concentration, light intensity, and temperature on luxury uptake of phosphorus by WSP microalgae in continuous culture bioreactors. Increasing temperature had a statistically significant "positive effect" on intracellular acid-insoluble polyphosphate concentration. It is likely that elevated temperature increased the rate of polyphosphate accumulation, but because the biomass was not starved of phosphate, the stored acid-insoluble polyphosphate was not utilized. Increasing light intensity had no effect on acid-insoluble polyphosphate but had a "negative effect" on the acid-soluble polyphosphate. A possible explanation for this is that the faster growth rate at high light intensity results in this form of polyphosphate being utilized by the cells for synthesis of cellular constituents at a rate that exceeds replenishment. The variability in the phosphorus content of the microalgal biomass shows that with this new understanding ofthe luxury uptake mechanism there is the potential to optimize WSP for biological phosphorus removal.

250 citations

Journal ArticleDOI
TL;DR: This paper provides the first long-term field data for slag filters, and shows that they can provide P removal for a half a decade before filter replacement/rejuvenation is required.

197 citations


Cited by
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Journal ArticleDOI
TL;DR: The ability of these CO2 consuming microalgae to purify biogas and concentrate methane is discussed, and anaerobic digestion of the whole biomass appears to be the optimal strategy on an energy balance basis for the energetic recovery of cell biomass.

1,153 citations

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TL;DR: The present review describes the advantages of microalgae for the production of biofuels and various bioactive compounds and discusses culturing parameters.
Abstract: Microalgae have recently attracted considerable interest worldwide, due to their extensive application potential in the renewable energy, biopharmaceutical, and nutraceutical industries. Microalgae are renewable, sustainable, and economical sources of biofuels, bioactive medicinal products, and food ingredients. Several microalgae species have been investigated for their potential as value-added products with remarkable pharmacological and biological qualities. As biofuels, they are a perfect substitute to liquid fossil fuels with respect to cost, renewability, and environmental concerns. Microalgae have a significant ability to convert atmospheric CO2 to useful products such as carbohydrates, lipids, and other bioactive metabolites. Although microalgae are feasible sources for bioenergy and biopharmaceuticals in general, some limitations and challenges remain, which must be overcome to upgrade the technology from pilot-phase to industrial level. The most challenging and crucial issues are enhancing microalgae growth rate and product synthesis, dewatering algae culture for biomass production, pretreating biomass, and optimizing the fermentation process in case of algal bioethanol production. The present review describes the advantages of microalgae for the production of biofuels and various bioactive compounds and discusses culturing parameters.

1,125 citations

Journal ArticleDOI
TL;DR: The impacts associated with algae production were determined using a stochastic life cycle model and compared with switchgrass, canola, and corn farming, and it is indicated that these conventional crops have lower environmental impacts than algae in energy use, greenhouse gas emissions, and water regardless of cultivation location.
Abstract: Algae are an attractive source of biomass energy since they do not compete with food crops and have higher energy yields per area than terrestrial crops. In spite of these advantages, algae cultivation has not yet been compared with conventional crops from a life cycle perspective. In this work, the impacts associated with algae production were determined using a stochastic life cycle model and compared with switchgrass, canola, and corn farming. The results indicate that these conventional crops have lower environmental impacts than algae in energy use, greenhouse gas emissions, and water regardless of cultivation location. Only in total land use and eutrophication potential do algae perform favorably. The large environmental footprint of algae cultivation is driven predominantly by upstream impacts, such as the demand for CO2 and fertilizer. To reduce these impacts, flue gas and, to a greater extent, wastewater could be used to offset most of the environmental burdens associated with algae. To demonstra...

1,064 citations

Journal ArticleDOI
TL;DR: The critical parameters that limit algal cultivation, production and harvest are reviewed and practical options that may enhance the net harvestable algal production from wastewater treatment HRAPs including CO(2) addition, species control, control of grazers and parasites and bioflocculation are discussed.

989 citations

Journal ArticleDOI
TL;DR: The use of high rate algal ponds (HRAPs) for nutrient removal has been in existence for some decades though the technology has not been fully harnessed for wastewater treatment as mentioned in this paper.

984 citations