Treatment of wastewater polluted with urea by counter-current thermal hydrolysis in an industrial urea plant

Barmaki, M.M.; Rahimpour, Mohammad Reza; Jahanmiri, A.

doi:10.1016/j.seppur.2009.02.007

Cited by 32 publications

(21 citation statements)

References 16 publications

(35 reference statements)

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“…Then, the use of wastewater containing urea seems to be the simplest solution. Typical urea containing wastes can come from fertilizer plants, urea synthesis industry, or human activities (sewage) [52,53]. In relation to calcium, this substrate could be obtained from calcium-rich wastewater, such as from citric acid production, landfill leachates, paper recycling, and bone processing [54].…”

Section: Substratesmentioning

confidence: 99%

Can Microbially Induced Calcite Precipitation (MICP) through a Ureolytic Pathway Be Successfully Applied for Removing Heavy Metals from Wastewaters?

et al. 2018

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Microbially induced calcite precipitation (MICP) through a ureolytic pathway is a process that promotes calcite precipitation as a result of the urease enzymatic activity of several microorganisms. It has been studied for different technological applications, such as soil bio-consolidation, bio-cementation, CO 2 sequestration, among others. Recently, this process has been proposed as a possible process for removing heavy metals from contaminated soils. However, no research has been reported dealing with the MICP process for heavy metal removal from wastewater/waters. This (re)view proposes to consider to such possibility. The main characteristics of MICP are presented and discussed. The precipitation of heavy metals contained in wastewaters/waters via MICP is exanimated based on process characteristics. Moreover, challenges for its successful implementation are discussed, such as the heavy metal tolerance of inoculum, ammonium release as product of urea hydrolysis, and so on. A semi-continuous operation in two steps (cell growth and bio-precipitation) is proposed. Finally, the wastewater from some typical industries releasing heavy metals are examined, discussing the technical barriers and feasibility.

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Section: Substratesmentioning

confidence: 99%

Can Microbially Induced Calcite Precipitation (MICP) through a Ureolytic Pathway Be Successfully Applied for Removing Heavy Metals from Wastewaters?

et al. 2018

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“…113 H kJ mol ∆ = + / However, there is evidence that the reaction takes place in two major steps [2,3] Where decomposition of carbamate leads to ammonia and carbon dioxide in the gas phase.…”

Section: Aqueous Urea Decomposition Chemistrymentioning

confidence: 99%

Aqueous Urea Decomposition Reactor: Reaction Modeling and Scale Up

Gargurevich¹

2016

J Chem Eng Process Technol

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“…For every ton of urea produced, 0.3 t of water is formed based on the synthesis reaction equation. This means that in a urea plant having a capacity of 1,500 t of urea per day, roughly 750-800 t of water has to be discharged as a wastewater stream from the process per day (Barmaki et al 2009). This wastewater stream usually contains about 0.…”

Section: Introductionmentioning

confidence: 99%

“…Since the early seventies, due in part to stricter environmental legislation, it has become increasingly necessary to reduce the urea content of plant wastewater (Rahimpour 2004). Today's requirements mostly call for a maximum concentration of 10 mg/L (Barmaki et al 2009;Rahimpour 2004).…”

Section: Introductionmentioning

confidence: 99%

“…This treatment method is considered to be costly, because it not only requires the application of pressure equipment but also consumes a large amount of medium pressure steam. Biological wastewater purification constitutes a potential solution to this problem but has a disadvantage that aerobic and anaerobic purification steps are always necessary, and there is no possibility of recovering or recycling the urea or the ammonia that may be obtained (Goorden 1981;Barmaki et al 2009). In order to ensure that the microorganisms exhibit high activity, the conditions such as temperature, pH, and urea concentration must be controlled strictly.…”

Section: Introductionmentioning

confidence: 99%

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Catalytic hydrolysis of urea from wastewater using different aluminas by a fixed bed reactor

Shen

et al. 2014

Environ Sci Pollut Res

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In order to find an effective method for treating urea wastewater, the experiments on the hydrolysis of urea in wastewater were conducted in a fixed bed reactor with different aluminas (α-Al2O3, γ-Al2O3, and η-Al2O3) as catalysts respectively in contrast with inert ceramic particle. The results indicate that the three alumina catalysts show obvious catalytic activity for urea hydrolysis at 125 °C. The order of activity is η-Al2O3 > γ-Al2O3 > α-Al2O3, and the activity difference increases with increasing temperature. According to the characterization results, surface acidity has little impact on the activity of catalyst. However, it was found that surface basicity of alumina catalyst plays an important role in catalytic hydrolysis of urea, and the activity of catalyst may be also influenced by the basic strength. With η-Al2O3 as catalyst, the urea concentration in wastewater is reduced to 4.96 mg/L at a temperature of 165 °C. Moreover, the η-Al2O3 shows a good stability for urea hydrolysis. The hydrolysis of urea over η-Al2O3 catalyst can evidently reduce the reaction temperature and is promising to replace industrial thermal hydrolysis process.

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Treatment of wastewater polluted with urea by counter-current thermal hydrolysis in an industrial urea plant

Cited by 32 publications

References 16 publications

Can Microbially Induced Calcite Precipitation (MICP) through a Ureolytic Pathway Be Successfully Applied for Removing Heavy Metals from Wastewaters?

Can Microbially Induced Calcite Precipitation (MICP) through a Ureolytic Pathway Be Successfully Applied for Removing Heavy Metals from Wastewaters?

Aqueous Urea Decomposition Reactor: Reaction Modeling and Scale Up

Catalytic hydrolysis of urea from wastewater using different aluminas by a fixed bed reactor

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