Optimisation of hydraulic performance to maximise faecal coliform removal in maturation ponds

Bracho, Nibis; Lloyd, B. J.; Aldana, Gerardo

doi:10.1016/j.watres.2006.02.007

Cited by 31 publications

(28 citation statements)

References 21 publications

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“…Segundo Bracho et al (2006), a desinfecção natural em lagoa de maturação requer a penetração da radiação solar na coluna d'água. Deve-se, então, priorizar a remoção de sólidos e nutrientes em sistemas anteriores à lagoa de maturação e, caso haja altas concentrações de sólidos suspensos, a remoção de Escherichia coli cairá acentuadamente.…”

Section: Resultsunclassified

Avaliação de sistema de tratamento de dejetos suínos instalado no estado de Santa Catarina

Araujo¹,

Oliveira²,

Alves³

et al. 2012

Rev. bras. eng. agríc. ambient.

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R ESU M OOs dejetos suínos contribuem de forma significativa em prol da degradação dos recursos naturais e para a diminuição da qualidade de vida na região sul do estado de Santa Catarina, Brasil. O excesso de dejetos gerados pelo grande número dos suínos por unidade de área dificulta a solução do problema. Este trabalho teve como objetivo avaliar o comportamento de um sistema de tratamento de dejetos suínos, em série e em escala real, composto de unidades anaeróbias, unidades aeróbias e pós-tratamento. Os parâmetros analisados foram: DBO, DQO, PT, P-PO 4 , N-NH 3 , NTK, pH, clorofila a, biomassa algal, coliformes totais e coliformes fecais (Escherichia coli). O sistema mostrou que após um ano de funcionamento as eficiências de remoção foram satisfatórias para matéria orgânica e nutrientes, alcançando valores de 97% para DBO, 95% para DQO, 88% para N-NH 3 e 74% para PT/P-PO 4 , mesmo com as variações de vazão e de carga orgânica aplicada. Entretanto, a remoção de coliformes fecais nas unidades aeróbias foi baixa, reduzindo somente 0,86 unidades log na lagoa facultativa aerada e 0,80 unidades log na lagoa de maturação. Palavras-chave: reatores anaeróbios, lagoas de estabilização, filtro de pedrasThe evaluation of swine waste treatment system installed in Santa Catarina State A B ST R A C T The swine manure contributes significantly to the degradation of natural resources and to decrease the quality of life in the southern state of Santa Catarina, Brazil. The excess of manure produced by the large number of pigs per unit area hinders the solution of the problem. This study aimed to evaluate the behavior of a system developed to treat swine manure, in series and in real scale, composed of anaerobic units, aerobic units and post-treatment. The parameters analyzed were: BOD, COD, TP, PO 4 -P, NH 3 -N, TKN, pH, chlorophyll a, algal biomass, total coliforms and fecal coliforms (Escherichia coli). The system showed that, after one year of operation, the removal efficiencies were satisfactory for organic matter and nutrients, reaching values of 97% for BOD, 95% for COD, 88% for N-NH 3 and 74% for PT/P-PO 4 , even with variations in flow and organic load applied. However the removal of fecal coliforms in the aerobic units was low, decreasing only 0.86 log units in the aerated facultative pond and 0.80 log units in the maturation pond.

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Section: Resultsunclassified

Avaliação de sistema de tratamento de dejetos suínos instalado no estado de Santa Catarina

Araujo¹,

Oliveira²,

Alves³

et al. 2012

Rev. bras. eng. agríc. ambient.

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“…This was done by assuming certain flow regimes and empirically evaluating die-off kinetics for microbial disinfection by either using plug flow , completely stirred tank reactor (CSTR) flow (Marais, 1974;Mayo, 1995;Von Sperling, 1999 or dispersed flow (Wehner and Wilhelm, 1956;Polprasert and Bhattarai, 1985;Qin et al, 1991;Herrera and Castillo, 2000;Von Sperling, 1999Bracho et al, 2006). These simple equations are particularly useful for quick estimations but suffer from inherent shortcomings that disallow the transient and spatial effects from sunlight disinfection.…”

Section: Introductionmentioning

confidence: 99%

Significance of buoyancy in turbulence closure for computational fluid dynamics modelling of ultraviolet disinfection in maturation ponds

et al. 2018

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Buoyancy-driven turbulent dispersion in a maturation pond is studied by a combination of field measurements and computational fluid dynamics. Modelling flow in maturation ponds requires turbulent closure models because of the large physical size and the need to model on diurnal time scales. Simulation results are shown to be more sensitive to the inclusion of a buoyancy production term appearing in the turbulent transport equations than to the model choice.Comparisons with experimental thermal profiles show that without this term, thermal mixing is over predicted. When including the term, stratification occurs but thermal mixing is under predicted in the lower water column. In terms of pond performance, the effect of this term is to 2 cause increased surface die-off of Escherichia coli during sunlight hours due to the generation of stratification. It is recommended that future modelling consider and implement this term.

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“…This explains why investigations on the influence of hydraulic pattern have focused on coliform removal and with good results (e.g. Lloyd and Vorkas, 1999;Shilton and Harrison, 2003;von Sperling, 2003;Shilton and Mara, 2005;Bracho et al, 2006). Mara and Pearson (1986) and Mara et al (1992) stated that limitations of "rational" methods based on first-order kinetics led to empirical procedures based on ambient temperature.…”

Section: Introductionmentioning

confidence: 99%

Revisiting the influence of loading on organic material removal in primary facultative ponds

Silva

Souza

Araújo

2010

Braz. J. Chem. Eng.

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-This paper investigated the influence of organic loading on BOD and COD removal in primary facultative ponds. The study was based on six full-scale pond plants in which average removals of unfiltered biochemical oxygen demand (BOD) and chemical oxygen demand (COD) were 72 and 50%, respectively. For filtered samples, the removals were 89 and 83%, respectively. First-order removal rates assuming ideal hydraulic patterns (completely mixed and plug-flow) decreased with increments in the mean hydraulic retention time (HRT). Reduction in organic loading also caused a decrease in removal rates. The results emphasized that HRT and surface organic loading are more reliable to estimate first-order removal rates than traditional Arrhenius-style equations. Thus, HRT and surface organic loading can be used to compute more realistic first-order removal rates and surface removal rates. An alternative design procedure based on HRT and surface organic loading was proposed and demonstrated.

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Optimisation of hydraulic performance to maximise faecal coliform removal in maturation ponds

Cited by 31 publications

References 21 publications

Avaliação de sistema de tratamento de dejetos suínos instalado no estado de Santa Catarina

Avaliação de sistema de tratamento de dejetos suínos instalado no estado de Santa Catarina

Significance of buoyancy in turbulence closure for computational fluid dynamics modelling of ultraviolet disinfection in maturation ponds

Revisiting the influence of loading on organic material removal in primary facultative ponds

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