Stabilization of source-separated human urine by chemical oxidation

Zhang, Yang; Li, Zifu; Zhao, Yuan; Chen, Shuangling; Mahmood, Ibrahim Babatunde

doi:10.2166/wst.2013.055

Cited by 19 publications

(13 citation statements)

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“…Urea hydrolysis can be prevented by inhibiting the microbial activity and hence the production of urea-degrading enzymes . This can be achieved by (i) the addition of acids to decrease the pH, − (ii) the addition of caustics, wood ash, or biochar to increase the pH, , (iii) the addition of hydrogen peroxide or urease inhibitors, (iv) filtration, (v) evaporation, (vi) electrochemical chlorine production, and (vii) thermal treatment . Interestingly, increasing the pH not only prevents urea hydrolysis but also can reduce the scaling potential of urine by inducing controlled precipitation of calcium and magnesium salts in a designated precipitation tank.…”

Section: Introductionmentioning

confidence: 99%

Electrochemically Induced Precipitation Enables Fresh Urine Stabilization and Facilitates Source Separation

Paepe

Pryck

Verliefde

et al. 2020

Environ. Sci. Technol.

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Source separation of urine can enable nutrient recycling, facilitate wastewater management, and conserve water. Without stabilization of the urine, urea is quickly hydrolyzed into ammonia and (bi)carbonate, causing nutrient loss, clogging of collection systems, ammonia volatilization, and odor nuisance. In this study, electrochemically induced precipitation and stabilization of fresh urine was successfully demonstrated. By recirculating the urine over the cathodic compartment of an electrochemical cell, the pH was increased due to the production of hydroxyl ions at the cathode. The pH increased to 11−12, decreasing calcium and magnesium concentrations by >80%, and minimizing scaling and clogging during downstream processing. At pH 11, urine could be stabilized for one week, while an increase to pH 12 allowed urine storage without urea hydrolysis for >18 months. By a smart selection of membranes [anion exchange membrane (AEM) with a cation exchange membrane (CEM) or a bipolar membrane (BPM)], no chemical input was required in the electrochemical cell and an acidic stream was produced that can be used to periodically rinse the electrochemical cell and toilet. On-site electrochemical treatment, close to the toilet, is a promising new concept to minimize clogging in collection systems by forcing controlled precipitation and to inhibit urea hydrolysis during storage until further treatment in more centralized nutrient recovery plants.

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Section: Introductionmentioning

confidence: 99%

Electrochemically Induced Precipitation Enables Fresh Urine Stabilization and Facilitates Source Separation

Paepe

Pryck

Verliefde

et al. 2020

Environ. Sci. Technol.

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“…Studies shows that adding 0.03 mol/L of hydrogen peroxide can inhibit the hydrolysis of urea in fresh urine (Zhang et al, 2013b). Furthermore, in urine contaminated by feces, the amount of hydrogen peroxide required increases with the degree of pollution.…”

Section: Heat Solar and Othersmentioning

confidence: 99%

Features and Applications of Urine Stabilization Methods: A Review

Yang

2021

Front. Sustain.

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The recovery of nutrients from unconventional water such as domestic sewage is considered as a sustainable solution to environmental sanitation, personal hygiene, water, and food safety issues. Source separation of urine and the sequenced treatment techniques are the promising approaches to recover the resources from this unconventional water. However, in the storage of urine, urea is hydrolyzed under the action of urease, resulting in odor, precipitation and the loss of ammonia, which is a challenge to be overcome in the process of urine recycling. This review collates research related to urine stabilization, and aims to summarize the characteristics and applications of existing urine stabilization methods, such as acidification, alkalization, electrochemistry, inhibitors and etc. Overall, acidification and alkalization have higher dosage requirements and have an attentional impact on the environment; electrochemical technology is suitable for decentralized sanitation facilities, but the inhibition duration is short; inhibitors are the least effective and are usually used to regulate urease activities in soil environment rather than for urine stabilization. Choosing the appropriate approaches of urine stabilization should focus on the overall perspective of urine resource utilization, consider the separation method and recovery form, and combine it with the concentration technology.

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“…Bacterial metabolism or thermal reactions produced offensive odor in urine (Troccaz et al, 2013). Ammonia is a major malodourous compound that is volatized during storage and urea hydrolysis (Zhang et al, 2013). In addition, organic compounds with low odor threshold values are found in urine after storage (Troccaz et al, 2013).…”

Section: Odor Reduced During Urine Lactic Acid Treatmentmentioning

confidence: 99%

Lactic acid from food waste enhances pathogen inactivation and urea stabilization in human urine

Getaneh¹,

Love²,

Desta³

et al. 2021

Int. J. Water Res. Environ. Eng.

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In areas where conventional sewer systems are not possible, innovative and low-cost methods are needed to get rid of pathogens in human urine. Treatment through acidification is a reliable method. In this study, the effect of fresh cabbage waste, potato peel, and teff flour water as substrate for lactic acid treatment of source-separated urine was investigated. Laboratory scale batch experiments were conducted to compare the substrates for pH 4 and high distribution of lactic acid bacteria (LAB), important for urine hygienization and urea stabilization. It was found that with the addition of 10% molasses as a sugar supplement, fermentation of fresh cabbage waste could establish the desired effect for lactic acid treatment of source-separated urine. The final pH in the urine mixed with lactic acid in the ratio of 1:1 and 1:2 (lactic acid: urine) was 4.12 and 4.26, respectively. While the final pH in the 1:4 and control reactors was 8.3 and 9.2, respectively. Escherichia coli count was below the detection limit in both 1:1 and 1:2 reactors after 5 days, whereas the number of E. coli in the samples collected from 1:4 and control reactors showed only slight reduction until the final day of the treatment process. Urea decomposition improved in 1:1 and 1:2 reactors, while it kept increasing in 1:4 and control reactors. The results revealed that food waste produced lactic acid enhances pathogen inactivation, urea stabilization and reduce odors in human urine.

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Stabilization of source-separated human urine by chemical oxidation

Cited by 19 publications

References 0 publications

Electrochemically Induced Precipitation Enables Fresh Urine Stabilization and Facilitates Source Separation

Electrochemically Induced Precipitation Enables Fresh Urine Stabilization and Facilitates Source Separation

Features and Applications of Urine Stabilization Methods: A Review

Lactic acid from food waste enhances pathogen inactivation and urea stabilization in human urine

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