Total Value of Phosphorus Recovery

Abstract

Phosphorus (P) is a critical, geographically concentrated, nonrenewable resource necessary to support global food production. In excess (e.g., due to runoff or wastewater discharges), P is also a primary cause of eutrophication. To reconcile the simultaneous shortage and overabundance of P, lost P flows must be recovered and reused, alongside improvements in P-use efficiency. While this motivation is increasingly being recognized, little P recovery is practiced today, as recovered P generally cannot compete with the relatively low cost of mined P. Therefore, P is often captured to prevent its release into the environment without beneficial recovery and reuse. However, additional incentives for P recovery emerge when accounting for the total value of P recovery. This article provides a comprehensive overview of the range of benefits of recovering P from waste streams, i.e., the total value of recovering P. This approach accounts for P products, as well as other assets that are associated with P and can be recovered in parallel, such as energy, nitrogen, metals and minerals, and water. Additionally, P recovery provides valuable services to society and the environment by protecting and improving environmental quality, enhancing efficiency of waste treatment facilities, and improving food security and social equity. The needs to make P recovery a reality are also discussed, including business models, bottlenecks, and policy and education strategies.

The Potential Phosphorus Crisis: Resource Conservation and Possible Escape Technologies: A Review

“…Recovery from the solid phase can also be achieved from the primary sludge, excess sludge after secondary sedimentation, the raw sludge before anaerobic digestion and the sludge before and after dewatering (locations S1-S5 in Figure 9). Crystals of struvite and calcium phosphate may also be obtained from sewage sludge or sludge ash with alternative processes: as an example, it is possible to recover P from sludge ash after incineration (location A in Figure 9), and this is actually the technology in which the most concentrated form of phosphorus will be obtained; 4-11% by weight comparable to phosphate rock with about 13% phosphorus content [47][48][49]. Phosphorus can be recovered from ashes by acid extraction or bioleaching.…”

Options for Improved Phosphorus Cycling and Use in Agriculture at the Field and Regional Scales

“…Certain recovered P products, such as biosolids, composts, and dehydrated pelletized manures, may face similar obstacles as their raw source materials, such as low P concentrations or presence of contaminants (Lu et al, 2012; Yuan et al, 2012; Schoumans et al, 2015; Weissengruber et al, 2018). Recovered products may also be economically and/or energetically expensive to produce or have low bioavailability to crops, making their use undesirable compared with soluble fertilizers made from mined phosphate rock (Egle et al, 2016; Mayer et al, 2016; Roy, 2017). However, the many benefits of P recovery from waste streams, including reduced environmental impairment, improved function of wastewater treatment plants, and the social benefit of local P fertilizer sources, make P recovery and reuse as fertilizer worthy of investigation (Cordell et al, 2011; Mayer et al, 2016; Roy, 2017; Huygens and Saveyn, 2018).…”

“…Recovered products may also be economically and/or energetically expensive to produce or have low bioavailability to crops, making their use undesirable compared with soluble fertilizers made from mined phosphate rock (Egle et al, 2016; Mayer et al, 2016; Roy, 2017). However, the many benefits of P recovery from waste streams, including reduced environmental impairment, improved function of wastewater treatment plants, and the social benefit of local P fertilizer sources, make P recovery and reuse as fertilizer worthy of investigation (Cordell et al, 2011; Mayer et al, 2016; Roy, 2017; Huygens and Saveyn, 2018). While most currently available P recovery technologies are not economically viable, the business case for P recovery from wastes can be improved by taking into account environmental and social benefits, as well as through co‐recovery of valuable products such as organic matter, other nutrients, metals such as gold and silver, and even water (Mayer et al, 2016).…”

Fit-for-purpose block polymer membranes molecularly engineered for water treatment

“…These features could, likewise, improve the separation performance of membranes lined with phosphate-chelating agents for the recovery of phosphorus from wastewater streams. 19,20 Moreover, the flexibility to freely modify these membranes with various chemistries could allow this platform to serve as a substrate for the incorporation of other highlyspecific binding moieties, such as cucurbiturils and cyclodextrins, which are effective agents for the capture of hydrophobic polarized molecules, respectively. In order to utilize the broad range of chemistries that can be introduced, and therefore separations that can be achieved, effective binding groups for solutes of interest must be identified.…”

“…16,17 There is a growing trend to view the nutrients, natural polymeric substances, and metal ions dissolved in wastewater streams as renewable resources that can be recovered. 16,[18][19][20][21][22] Such that, if the appropriate technological solutions can be developed, recouping the value of these resources may help ameliorate the economic costs associated with reuse. These factors have, therefore, driven research into the development of hybrid membrane processes that seek to treat water to the purity levels demanded by the requirements of its end-users, while also recovering useful resources from the feed stream.…”