A dynamic model of the high-rate algal-bacterial wastewater treatment pond

Buhr, H. O.; Miller, Steve

doi:10.1016/0043-1354(83)90283-x

Cited by 83 publications

(84 citation statements)

References 6 publications

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“…La présence d'une agitation ou turbulence favorise le transfert de l'ammoniac de ta solution aqueuse vers l'atmosphère. Dans le LHR les conditions permettant la volatilisation de NH 3 sont réunies : l'activité algale intense qui s'y développe s'accompagne d'une augmentation du pH suite à l'assimilation photosynthétique des bicarbonates (AZOV, 1982 ;BUHR et MILLER, 1983 ;RICHMOND, 1986, DUBINSKY, 1986. Les pH peuvent atteindre des valeurs proches de 10.…”

Section: Elimination De L'azoteunclassified

Elimination de l'azote et du phosphore dans un lagunage à haut rendement

Halouani¹,

Picoti²,

Casellas³

et al. 2005

rseau

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L'objectif de cette étude est de comprendre le fonctionnement épuratoire de l'écosystème particulier que constitue le lagunage à haut rendement (LHR) afin de déterminer les principaux facteurs responsables de l'élimination de l'azote et du phosphore. Sur un bassin de 48 m2, alimenté eu eaux usées domestiques préalablement traitées pendant une semaine dans un bassin primaire ont été suivies selon un rythme hebdomadaire les formes carbonées, azotées et phosphorées dis-soutes et particulaires, les variables caractéristiques de l'activité photosynthétiques (chlorophylle a, pH et 02) et les données climatiques (rayonnement solaire et température). Une analyse en composantes principales réalisée sur l'ensemble des résultats a montré, d'une part l'opposition des variables climatiques et photosynthétiques aux formes minérales de l'azote et du phosphore (N-NH4 et P-PO4) et d'autre part l'influence de la charge organique sur le fonctionnement du système. L'évolution des formes azotées et phosphorées présente un effet saisonnier marqué. En hiver ou lors de surcharge organique importante, une augmentation du temps de séjour peut améliorer les rendements épuratoires. L'évolution de la matière organique dissoute est indépendante du cycle saisonnier. Au cours des deux années du suivi on observe une adaptation progressive de l'écosystème à la dégradation de la matière organique. Dans le lagunage à haut rendement l'élimination de l'azote et du phosphore est liée principalement à l'activité algale, qui entraîne une assimilation biologique et une élévation du pH, responsables des phénomènes chimiques de volatilisation de l'azote ammoniacal et de précipitation de phosphate de calcium.

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Section: Elimination De L'azoteunclassified

Elimination de l'azote et du phosphore dans un lagunage à haut rendement

Halouani¹,

Picoti²,

Casellas³

et al. 2005

rseau

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“…The value of such work towards maximizing the growth of specific species in (very) high biomass systems is limited, with the drivers for the work (both modelling, and logistic/financial) being very different. At the interface is the growth of microalgae in sewage ponds, for which modelling has been shown to have utility (Buhr & Miller 1983;Llorens et al 1991). Modelling applications towards technologically similar waste effluent treatment systems involving microalgae are similarly possible (e.g.…”

Section: Optimization Of Bioreactor Design and Operationmentioning

confidence: 99%

Placing microalgae on the biofuels priority list: a review of the technological challenges

Greenwell

Laurens

Shields

et al. 2009

J. R. Soc. Interface.

704

359

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Microalgae provide various potential advantages for biofuel production when compared with 'traditional' crops. Specifically, large-scale microalgal culture need not compete for arable land, while in theory their productivity is greater. In consequence, there has been resurgence in interest and a proliferation of algae fuel projects. However, while on a theoretical basis, microalgae may produce between 10-and 100-fold more oil per acre, such capacities have not been validated on a commercial scale. We critically review current designs of algal culture facilities, including photobioreactors and open ponds, with regards to photosynthetic productivity and associated biomass and oil production and include an analysis of alternative approaches using models, balancing space needs, productivity and biomass concentrations, together with nutrient requirements. In the light of the current interest in synthetic genomics and genetic modifications, we also evaluate the options for potential metabolic engineering of the lipid biosynthesis pathways of microalgae. We conclude that although significant literature exists on microalgal growth and biochemistry, significantly more work needs to be undertaken to understand and potentially manipulate algal lipid metabolism. Furthermore, with regards to chemical upgrading of algal lipids and biomass, we describe alternative fuel synthesis routes, and discuss and evaluate the application of catalysts traditionally used for plant oils. Simulations that incorporate financial elements, along with fluid dynamics and algae growth models, are likely to be increasingly useful for predicting reactor design efficiency and life cycle analysis to determine the viability of the various options for largescale culture. The greatest potential for cost reduction and increased yields most probably lies within closed or hybrid closed -open production systems.

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“…Even when the soil is nearly saturated, the rate is ∼ 1-10 s −1 ( → 1, θ ≈ θ s ). For comparison, studies on waste water treatment used the rate of ≈ 6.9 × 10 −5 s −1 (Buhr and Miller, 1983;Yang, 2011). Thus, mass transfer between gas and liquid in unsaturated soils is assumed to be rapid, and the concentration at each phase is always at equilibrium following Henry's law:…”

Section: Mass Transfer Between Gas and Liquidmentioning

confidence: 99%

“…Some mathematical models have introduced pH estimation for systems with phototrophs under light-dark cycles, such as algal ponds (Buhr and Miller, 1983;Yang, 2011;Gomez et al, 2014) and phototrophic biofilms (Wolf et al, 2007). The algal pond models invoke solution equilibrium and charge neutrality and employ differential algebraic equations to estimate pH, while the phototrophic biofilm models consider acid-base reactions with rate equations by proposing near-equilibrium kinetics.…”

Section: Mass Transfer Between Gas and Liquidmentioning

confidence: 99%

Hydration status and diurnal trophic interactions shape microbial community function in desert biocrusts

Kim

2017

Biogeosciences

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Abstract. Biological soil crusts (biocrusts) are selforganised thin assemblies of microbes, lichens, and mosses that are ubiquitous in arid regions and serve as important ecological and biogeochemical hotspots. Biocrust ecological function is intricately shaped by strong gradients of water, light, oxygen, and dynamics in the abundance and spatial organisation of the microbial community within a few millimetres of the soil surface. We report a mechanistic model that links the biophysical and chemical processes that shape the functioning of biocrust representative microbial communities that interact trophically and respond dynamically to cycles of hydration, light, and temperature. The model captures key features of carbon and nitrogen cycling within biocrusts, such as microbial activity and distribution (during early stages of biocrust establishment) under diurnal cycles and the associated dynamics of biogeochemical fluxes at different hydration conditions. The study offers new insights into the highly dynamic and localised processes performed by microbial communities within thin desert biocrusts.

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A dynamic model of the high-rate algal-bacterial wastewater treatment pond

Cited by 83 publications

References 6 publications

Elimination de l'azote et du phosphore dans un lagunage à haut rendement

Elimination de l'azote et du phosphore dans un lagunage à haut rendement

Placing microalgae on the biofuels priority list: a review of the technological challenges

Hydration status and diurnal trophic interactions shape microbial community function in desert biocrusts

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