Recovering, Stabilizing, and Reusing Nitrogen and Carbon from Nutrient-Containing Liquid Waste as Ammonium Carbonate Fertilizer

Abstract

Ammonium carbonates are a group of fertilizer materials that include ammonium bicarbonate, ammonium carbonate hydrate, and ammonium carbamate. They can be synthesized from diverse nutrient-bearing liquid waste streams but are unstable in a moist environment. While extensively utilized several decades ago, their use gradually decreased in favor of large-scale, facility-synthesized urea fertilizers. The emergence of sustainable agriculture, however, necessitates the recovery and reuse of nutrients using conventional feedstocks, such as natural gas and air-derived nitrogen, and nutrient-containing biogenic waste streams. To this extent, anaerobic digestion liquid presents a convenient source of solid nitrogen and carbon to produce solid fertilizers, since no significant chemical transformations are needed as nitrogen is already present as an ammonium ion. This review describes detailed examples of such feedstocks and the methods required to concentrate and crystallize solid ammonium carbonates. The technologies currently proposed or utilized to stabilize ammonium carbonate materials in the environment are described in detail. Finally, the agricultural efficiency of these materials as nitrogen and carbon source is also described.

Mechanochemically Synthesized Nitrogen-Efficient Mg- and Zn-Ammonium Carbonate Fertilizers

“…Atom economy argument, a metric of the process’ greenness, suggests that exact stoichiometric quantities of starting materials will result in the highest sustainability . Ammonium bicarbonate (NH 4 HCO 3 further referred to as ABC) adheres to these principles and has recently been proposed as a sustainable source of both nitrogen and carbon to soil and plants . ABC was one of the main fertilizers used in China some 20 years ago until its use decreased due to the emergence of urea .…”

“…ABC was one of the main fertilizers used in China some 20 years ago until its use decreased due to the emergence of urea . This is due to its poor environmental stability since it readily decomposes back into NH 3 and CO 2 at room temperature . It is excluded from the organic fertilizer register in the US, not allowed as a standalone fertilizer in the EU and it is currently used as a fumigant .…”

“…It is excluded from the organic fertilizer register in the US, not allowed as a standalone fertilizer in the EU and it is currently used as a fumigant . If the methods can be developed by formulating ABC into solid materials that do not have any negative impacts on the biota, do not volatilize spontaneously, and contribute nitrogen to the plant growth, a tremendous benefit to the agriculture sector would result . The technologies to extract solid ABC from digestate should be available on a large scale for distributed operation and have already been estimated to be cost and environmentally efficient. ,, The path in physicochemical stabilization of ABC potentially lies in green mechanochemical stabilization technologies, as recently shown when addressing urea environmental stability problems. − In this work, we performed the mechanochemical synthesis of Mg and Zn containing double salts using widely available minerals such as magnesite, MgCO 3 , or smithsonite, ZnCO 3 .…”

Interactions of Urea Surfaces with Water as Relative Humidity Obtained from Dynamic Vapor Sorption Experiments, In Situ Single-Particle Raman Spectroscopy, and Ab Initio Calculations

“…Additionally, NH 4 + resulting from urea hydrolysis is oxidized to NO 3 – , which further can be subjected to denitrifying bacteria, culminating in the release of reactive nitrogen compounds, for instance, N 2 O. It is worth noting that the greenhouse gas potential of N 2 O is approximately 300 times more potent than CO 2 . – The implications of N loss extend beyond environmental concerns and intersect with energy pollution. Specifically, the production of NH 3 , a precursor to urea, has been implicated in significant energy consumption accounting for an estimated 3–5% of the total yield from natural gas and between 1 and 2% of the world’s energy resources. , Furthermore, due to the large influx of urea into the environment as a mineral fertilizer, it significantly contributes to the dissolved organic nitrogen in rainwater and aqueous aerosols .…”