Features and Applications of Urine Stabilization Methods: A Review

Abstract

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.

Multiple-Dose Pharmacokinetics and Safety of Mitragynine, the Major Alkaloid of Kratom, in Rats

“…The other limitation is the stability of MTG and its metabolites in urine under enzyme-reaction conditions. Adding stabilizers or finding other alternative ways to analyze the conjugated reaction should be considered in the following investigations . The quantifiable results for the phase II biotransformation will provide crucial information about the metabolism and toxicology of MTG.…”

Urea catalytic oxidation for energy and environmental applications

“…1,2 Urea is one of the most crucial reactive nitrogen in the nitrogen cycle and plays an indispensable role in the water-energy-food nexus. [3][4][5][6][7] Industrially, urea is a nitrogenreleasing fertilizer that accounts for about half of global nitrogen fertilizer consumption. 8,9 More importantly, urea has been demonstrated as a suitable hydrogen carrier for long-term sustainable energy supply due to its unique merits, such as non-toxicity, non-flammability, cost-effectiveness, easy storage and transportation, ideal energy density, and high hydrogen content (6.7 wt%).…”

Modular Functionalization of Metal‐Organic Frameworks for Nitrogen Recovery from Fresh Urine**

“…[13,[20][21][22] However, ammonia/ammonium recovery from stored urine relies heavily on the complete hydrolysis of urea which can take up to days depending on the specific environment. [21,23,24] This duration further requires ample space for urine storage, efforts for urine collection and transportation, and sophisticated urine stabilization prior to the nitrogen recovery treatment [25] -all of which lead to higher capital costs and maintenance expenses. [26,27] Additionally, a substantial amount of ammonia-nitrogen is lost during the long-term urine storage period, [26] which fundamentally reduces the overall nitrogen recovery efficiency of the treatment process.…”