Kinetics of the Desorption of Ammonia from Water by Diffused Aeration

Patoczka, Jerzy; Wilson, David J.

doi:10.1080/01496398408059939

Cited by 18 publications

(14 citation statements)

References 2 publications

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“…Inactivation of pathogens at pH levels above 11 has been shown to be more significant during the first 24 h as per the findings of Bina et al [21]. Specifically, for helminth eggs, the minimum exposure times reportedly range between 2 h and more than 180 days in order to achieve more than 90% inactivation of the helminth eggs [35]. This is however dependent on the type of alkaline agent, dosage and temperature.…”

Section: Resultssupporting

confidence: 51%

“…Moreover, the reduction in pH can be attributed to ammonia volitalization because the containers were kept opened. Per available studies [35,36], desorption of ammonia from wastewater occurs at high pH when the wastewater comes into contact with large amounts of air and eventually results in a decrease in pH. The pH of all the mixtures for the 16-day monitoring period ranged between a minimum of 7.8 and a maximum of 8.38 ( Figure 1a).…”

Section: Resultsmentioning

confidence: 99%

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Sanitizing Fecal Sludge for Reuse Using Wood Ash as an Additive

Monney

Awuah

2015

Recycling

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Wood ash has been widely used as an additive for excreta from dry compost toilets to sanitize it for reuse. However, there is dearth of quantitative information about its efficiency in sanitizing partially digested sludge from wet onsite sanitation systems. This paper presents findings of a series of two experimental studies to assess optimum wood ash dosages required to raise the pH of partially digested fecal sludge to sanitizing levels (pH > 11) in a tropical climate. The study monitored the variation of pH of the sludge containing between 0 (control) and 180 g of ash per litre of sludge. Average initial pH and total solids of the sludge were 7.79 and 72 g/L respectively. Generally, the magnitude and rapidity of pH spike was correlated with the ash dosage (r = 0.988) and was statistically significant (p = 0.0015; Fcrit = 2.3157) among all dosages. Drastic increase in pH (from 7.81 to 11.60 ± 0.07) was recorded in the first 24 h for ash dosages between 140 g/L and 180 g/L, whereas dosages below 140 g/L had pH values less than 10. The difference in variation of pH between the first 24 h and the successive 24 h was statistically significant (P(T ≤ t)two-tail = 0.00; tcrit = 2.09). On the average, 97% of the overall pH increment within a 48-h monitoring period occurred in the first 24 h for the 140-180 g/L ash dosages. The optimum ash dosages are 7-15 times higher than reported lime dosages but ash provides a cheaper alternative than lime for recycling plant nutrients. Further studies on pathogen inactivation efficiency are ongoing. OPEN ACCESSRecycling 2015, 1 15

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Section: Resultssupporting

confidence: 51%

Section: Resultsmentioning

confidence: 99%

Sanitizing Fecal Sludge for Reuse Using Wood Ash as an Additive

Monney

Awuah

2015

Recycling

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“…Therefore at appropriate temperatures and pH values ammonia can be released from water by volatilisation to the atmosphere. This principle has been in use for the design of desorption towers in industrial wastewater treatment, which require a high air-to-water ratio as the ammonia mass transfer is a gas phase-controlled process (Patoczka and Wilson, 1984 + -N/L and potassium phosphate buffer) was circulated along a closed loop system. A set of experiments to calculate ammonia losses was carried out under different pH values (7.5, 8.0, 8.5, 9.0 and 9.5) and water temperatures (15, 20, 25 and 30ºC), and the results showed that on average 50 percent of the total ammonium was removed in 14 hours at pH = 8.5 and T = 20ºC.…”

Section: Introductionmentioning

confidence: 99%

Ammonia volatilisation in waste stabilisation ponds: a cascade of misinterpretations?

Camargo‐Valero

Mara

2010

Water Science and Technology

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Ammonia volatilisation has generally been reported as, or assumed to be, the main nitrogen removal mechanism in waste stabilization ponds (WSP). Nitrogen removal via ammonia volatilisation is based on two observations: (a) in-pond pH values can reach high values (>9, even >10), so increasing the proportion of the total ammonia present as the un-ionized form or free ammonia (NH 3 ); and (b) in-pond temperatures can also be high, so improving the mass transfer rate of free ammonia to the atmosphere. Consequently, one of the most widely accepted models for ammonia removal in WSP is that reported by Pano and Middlebrooks in 1982, which was developed to reflect the occurrence of these two observations. This work reports how simple mathematical models for ammonia volatilisation in WSP, in spite of the possibility of their giving good predictions, may not accurately describe the main pathways and mechanisms involved in ammonia removal in WSP. KeywordsAmmonia volatilisation; biological nitrogen uptake; maturation ponds; nitrogen removal INTRODUCTION Ammonia volatilisation has been reported as the main nitrogen removal mechanism in waste stabilization ponds (WSP) during periods when temperature and pH (>10) are favourable (Maynard et al., 1999). Ammonia removal in WSP has been estimated by using the model developed by Pano and Middlebrooks (1982), which is one of the most widely accepted to describe ammonia volatilisation processes in facultative and maturation ponds. This model is based on first-order kinetics in a completely mixed reactor and is dependent on variables such as pH, temperature and hydraulic loading rate. Similar conclusions with regard to the importance of ammonia volatilisation on nitrogen removal in WSP have been also reported by using mass-transfer models which specifically consider the aqueous ammonia-water equilibrium system (Rockne and Brezonik, 2006). Slight variations from the original Pano and Middlebrooks model have been reported in order to introduce the effect of local weather and operational characteristics, and their authors agreed that ammonia volatilisation could be the predominant pathway for nitrogen and ammonia removal in WSP (Silva et al., 1995;Soares et al., 1996;Bastos et al., 2007). Indeed it is also assumed to be the predominant pathway in current models developed for plug-flow and complete-mix conditions and used for predicting total nitrogen removal in WSP (Crites et al., 2006). However, none of these models has been calibrated or validated by means of direct measurements of ex-pond ammonia volatilisation rates. Recent work reported by Zimmo et al. (2003), Zhou et al. (2006) and Camargo Valero and Mara (2007a) have pointed out that ammonia volatilisation makes only a small contribution to the overall performance of nitrogen removal in WSP, despite the fact that the Pano and Middlebrooks model and its variations still make reasonable predictions of ammonia removal within facultative and maturation ponds. In this paper we review the evidence for and against the usefulness ...

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“…This type of device is important for groundwater studies to provide data on gas mass flow rate and composition. The ebullition occurring at a spring discharge may act to strip out dissolved gases, which would introduce error into a dissolved gas analysis (White et al ; Baird et al ; Patoczka and Wilson ; Lucchetti and Gray ; Vroblesky and Lorah ; Mariner et al ). Failing to account for the free gas phase may introduce significant errors in determining the total gas present and thereby alter measurements of interest, such as water age dating (Taran ).…”

Section: Introductionmentioning

confidence: 99%

An Instrument for the Determination of a Hydropneumograph in a Bubbling Spring

Agnew¹,

Halihan

Holtzhower

et al. 2019

Groundwater

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In order to enable greater accuracy in the determination of the mass discharge of gas and water‐gas ratios (WGR) in groundwater from springs, we have developed a field‐deployable instrument using commercially available components to independently measure the gas and water mass flow rates in springs with bubbling mixed‐phase flow. Collecting and measuring the free gas phase will allow for further compositional analysis that may be useful in improving gas‐derived parameters such as recharge temperature and age, as well as quantification of methanogenesis and flux of crustal/mantle gasses. By installing a phase separator at the spring discharge, a thermal mass flow sensor is utilized to measure the gas flow rate (ebullition + flux) generated from a spring. The water flow rate is determined by a standard weir. Field performance of the device was tested on a spring discharging from the Arbuckle‐Simpson aquifer near the town of Connerville in south‐central Oklahoma, USA.

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Kinetics of the Desorption of Ammonia from Water by Diffused Aeration

Cited by 18 publications

References 2 publications

Sanitizing Fecal Sludge for Reuse Using Wood Ash as an Additive

Sanitizing Fecal Sludge for Reuse Using Wood Ash as an Additive

Ammonia volatilisation in waste stabilisation ponds: a cascade of misinterpretations?

An Instrument for the Determination of a Hydropneumograph in a Bubbling Spring

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