Mainstream Ammonium Recovery to Advance Sustainable Urban Wastewater Management

Abstract

Throughout the 20th century, the prevailing approach toward nitrogen management in municipal wastewater treatment was to remove ammonium by transforming it into dinitrogen (N 2 ) using biological processes such as conventional activated sludge. While this has been a very successful strategy for safeguarding human health and protecting aquatic ecosystems, the conversion of ammonium into its elemental form is incompatible with the developing circular economy of the 21st century. Equally important, the activated sludge process and other emerging ammonium removal pathways have several environmental and technological limitations. Here, we assess that the theoretical energy embedded in ammonium in domestic wastewater represents roughly 38−48% of the embedded chemical energy available in the whole of the discharged bodily waste. The current routes for ammonium removal not only neglect the energy embedded in ammonium, but they can also produce N 2 O, a very strong greenhouse gas, with such emissions comprising the equivalent of 14−26% of the overall carbon footprint of wastewater treatment plants. N 2 O emissions often exceed the carbon emissions related to the electricity consumption for the process requirements of WWTPs. Considering these limitations, there is a need to develop alternative ammonium management approaches that center around recovery of ammonium from domestic wastewater rather than deal with its "destruction" into elemental dinitrogen. Current ammonium recovery techniques are applicable only at orders of magnitude above domestic wastewater strength, and so new techniques based on physicochemical adsorption are of particular interest. A new pathway is proposed that allows for mainstream ammonium recovery from wastewater based on physicochemical adsorption through development of polymer-based adsorbents. Provided adequate adsorbents corresponding to characteristics outlined in this paper are designed and brought to industrial production, this adsorption-based approach opens perspectives for mainstream continuous adsorption coupled with side-stream recovery of ammonium with minimal chemical requirements. This proposed pathway can bring forward an effective resource-oriented approach to upgrade the fate of ammonium in urban water management without generating hidden externalized environmental costs.

The Adsorption of Ammonium Nitrogen from Milking Parlor Wastewater Using Pomegranate Peel Powder for Sustainable Water, Resources, and Waste Management

“…Among existent kinetics models, the pseudo-second order kinetic model, a plot of (t/qt) against (t), fits well with adsorption kinetic data according to the value of the correlation coefficient (R 2 > 0.99), as shown in Figure 12. Equations (6) and (7) are equations and linearized forms of the pseudo-second order model, respectively.…”

“…Current wastewater treatment technologies place a heavy burden on dairy farm management, thus illustrating the need for simple, robust, and effective technology that requires low investment and maintenance costs [6]. Many methods, including biological processes, air stripping, and membrane technologies, have been developed to remove and recover NH4-N from wastewater, though all of these methods have shown many disadvantages [7,8]. However, adsorption technology has proven to have promising features, such as its simplicity, cost effectivity, and potential to recover and reuse ammonium [9].…”

Geo-Agriculture: Reviewing Opportunities through Which the Geosphere Can Help Address Emerging Crop Production Challenges

“…The use of geological materials in technologies to mitigate both N and P loss in agricultural settings is receiving increasing attention. Zeolites and clays are ideally suited for binding with ammonium (NH 4 + ) due to their permanent negative charge [66,67]. Various positively-charged geomaterials including nano-scale aluminium oxides [68], iron oxides/hydroxides [69,70], layered hydroxides [71], and modified clays [72] have been trialed to remove nitrates (NO 3 − ), nitrites (NO 2 − ), and phosphates (PO 4 3− ) from agricultural effluents.…”

Functional starch-based hydrogels: renewable material solutions for wastewater and agriculture industries

“…Bioderived materials have recently been of interest to researchers in their effort to develop sustainable solutions for nutrient management with respect to improving farming systems and wastewater treatment technologies (Guilherme et al, 2015). Starch in particular has shown great application potential as an economical feedstock in the development of new technologies aimed at increasing the crop water availability, controlling soil erosion and reducing the loss of N from soil, as well as enabling the recovery of nutrients from wastewater (Cruz et al, 2019). In addition to being chemically modifiable, starch is abundant, renewable and biodegradable (Laycock & Halley, 2014;.…”

“…The main advantage of N recovery using adsorption is the simple design and application of this method. In addition, the adsorption process is effective and commercially viable (Cruz et al, 2019). Furthermore, the nutrient-laden sorbent or exchange media can potentially be applied as a nutrient product in agriculture directly after the removal process.…”