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Review

Recycling Phosphorus from Agricultural Streams: Grey and Green Solutions

by
Nicolò Auteri
*,
Filippo Saiano
and
Riccardo Scalenghe
Dipartimento di Scienze Agrarie, Alimentari e Forestali, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy
*
Author to whom correspondence should be addressed.
Agronomy 2022, 12(12), 2938; https://doi.org/10.3390/agronomy12122938
Submission received: 26 October 2022 / Revised: 16 November 2022 / Accepted: 22 November 2022 / Published: 24 November 2022
(This article belongs to the Topic Eco-Sustainable Innovative Approaches for Water-Soil-Nutrient-Crop Management)
Versions Notes

Abstract

:
Many intensively farmed soils show high phosphorus (P) contents compared to the thresholds required for agricultural production; 0.084 Mt of P year−1 is leaving the European terrestrial system. This paper focuses mainly on non-point flows of P and provides an overview of the most promising and sustainable solutions for P recycling, centred on waste materials from agriculture. Given the global shortage of the primary resource of P, its management is critical for its efficient use. Nowadays, wastage and loss at every stage of the P cycle raise concerns about future supplies and especially about the resulting environmental problems, such as the eutrophication of surface water bodies and the reduction of biodiversity. Recovering P costs more than EUR 640 per tonne depending on the type of technique used. The opportunity for P recovery with green and sustainable technology is, therefore, a great challenge for the next years. Waste materials or by-products of agricultural processing have been considered ecologically safe, low-cost, and highly selective with high pollutant adsorption capacities, which would enable sustainable P recovery, both environmentally and economically. A realistic threshold for considering the reuse of P sustainably at the farm level is EUR 320 per tonne.

1. Introduction

The continuing increase in the world’s population poses a crucial risk to environmental emergencies, such as the supply of finite (limited) raw materials such as phosphorite, from which phosphorus (P), a key nutrient for ensuring global food support, is derived [1].
In addition, the increasing demand for commodities has intensely augmented attentiveness to their recycling and reuse; no current production process scheme is imaginable without considering the by-products, residues, and wastes [2]. Phosphorus (P) is a crucial element for producing crops and is widely used in both recycled manure and inorganic fertiliser [3,4]. Its cycle has a high impact on the total environment, interfacing the hydrosphere and the pedosphere, and being heavily dependent on the biosphere and anthroposphere. Today, the global society faces serious challenges given the scarcity, importance, unequal global distribution, and, at the same time, regional excess of P. Phosphorite, the primary resource from which P is extracted, is concentrated in a few areas of the globe, with China, Morocco, the United States, Jordan, and Saudi Arabia being the leading producers, followed by ongoing capacity expansion projects in Brazil, Kazakhstan, Mexico, Russia, and South Africa [5,6]. The approximate annual global consumption for P is 3 kg per capita, which has been rising over time for most regions [7]. However, the amounts of P available and price volatilities, as occurred in 2008, have given rise to concerns about future supplies and water and soil pollution, encouraging moves toward the recycling of P [8].
Ninety per cent of extracted P is used for food production [9], mostly indirectly as fertiliser. Therefore, food production depends on a non-renewable resource, which, in recent decades, has become progressively expensive due to the growing global demand, with negative environmental impacts caused by constant mining [10,11,12].
Europe is the most import-dependent region, with 86% of P’s total demand [13]. In EU agriculture, 1.1 million t of P fertiliser was used, a slight reduction of 6.5% since 2012 [14]. Waste deriving from industrial processes, such as sludge, contains agronomical valuable P, so its application on cropland might decrease the necessity of mined fertilisers, but its riskiest contraindication is the content of potentially harmful organic and inorganic contaminants [15]. Given this dependence on P and the global shortage of the primary resource of P, management is critical for the efficient use of P resources. Considering that P management might not be low-cost but is the only option to maintain P supply, as P is not replaceable or renewable, we should be investing in sustainable strategies that will, on the one hand, increase productivity in the short term and, on the other hand, could be a probable low-cost guarantee for the future, supporting the food supply and farmers and safeguarding water quality [16]. The Raw Materials Initiative of the European Commission addresses challenges related to access to raw materials by identifying materials with a high supply risk and economic importance, to which reliable and unhindered access is critical for industry and value chains (Table 1); they set the fundamental importance of phosphate rock. The list should help boost European production of critical raw materials by strengthening recycling activities and, if necessary, facilitating the launch of new recycled materials in line with environmental sustainability and the circular economy. Additionally, it provides a better understanding of how the security of the supply of raw materials can be ensured through diversification, the use of different geographic sources, mining, recycling, or substitution. Critical raw materials are a priority in the Circular Economy Action Plan of the European Union, which aims to promote their efficient use and recycling [17].
Phosphate rock is a finite resource for all practical purposes, subject to price volatility, with varying quality and unequal access across the globe. Additionally, although there is an overall vagueness as to when the peak will be reached, there is a large consensus that the remaining phosphate rock reserves are declining [18]. According to USGS data (2022), almost 220 million t of phosphate rock was extracted in 2021 from global mineral reserves, but only about 0.03 million t were marketable. Of this marketable phosphate rock, consumers used more than 99% in the same year for an estimated EUR 1940 million in sold products. Marketable phosphate rock contains less than 18% P. Therefore, the geopolitical situation can have a significant influence on the availability and price of P; the other dimensions of this issue (price, quality, access) seem more compelling to us currently. Thus, the growing perception of a global P crisis could lead to serious international tensions due to both the distribution of terrestrial reserves and their control, as well as global population growth [19]. According to the European Sustainable Phosphorus Platform (ESPP), the annual world market for phosphate fertilisers is around EUR 45–60 billion. At the time of writing, the price of rock phosphate is EUR 320 per metric ton (+85% February to September 2022) (from https://www.indexmundi.com/commodities/ accessed on 20 November 2022), while diammonium phosphate exceeds EUR 1000 per ton, reflecting the fertiliser end-user price (from https://www.agrarmarkt-nrw.de/duengermarkt.shtm, accessed on 20 November 2022). These are strong arguments for pursuing a circular P economy now, regardless of the exact timetable of phosphate rock resource depletion. Given these issues, P recovery strategies represent the solution to collapsing fertiliser supplies and the growing problem of eutrophication. Economically, P recovery is also beneficial when compared to the potential economic loss due to its release [20].
The current literature on P reuse and recycling has increased dramatically in the recent decade, according to both Scopus and Web of Knowledge, and Elsevier’s and Clarivate’s abstract and citation databases. This review describes the current industrial alternatives for recovering lost P (grey removal) and proposes bio-based solutions for P recycling (green removal). P recycling from both non-point sources and point sources, such as urban and livestock wastewater, focusing on the reuse of materials derived from agriculture waste, would result in lower costs and environmental impact and could lower P excess.

2. P in the Soil Environment

2.1. Overfertilised Soils

The presence of P is essential for modern agriculture. However, fertiliser efficiency varies between regions, and in general, less than 20% of the P absorbed by the plants is then harvested [21]. Globally, farmers apply about 25 Mt P year−1, and about 14 Mt P year−1 is not used by crops, becoming a pollutant. This means that more than half is lost to the environment and can create ecological imbalances in ecosystems and water bodies. Therefore, it is crucial to provide crops with the correct amounts of fertilisers to avoid excesses [22]. In Europe, Panagos et al. [23] estimated the total P in agricultural topsoil (0–20 cm) at a mean of 1412 kg ha−1. A high soil P concentration, conferring no direct agronomic advantage, has resulted in inefficient resource use [24]. When considering European agricultural soils (171 million ha; not considering set-aside agricultural land), P input with inorganic fertilisers is estimated to be a total of 1.3 Mt P year−1. Of which about 11% is estimated as a P year−1 surplus, and total P losses in river basins and outlets have been estimated to be about 0.1 Mt P year−1 [23]. Therefore, best practices should be to estimate the recommended threshold values for soil P testing (STP), a good indicator for the potential risk of phosphorus movement at the edge-of-field into downstream waters, based on routine soil sampling and analysis that have been identified to help assess the likely yield response to P applied on-farm [25]. However, many regions with intensive agriculture have STP values above the threshold values required for optimal agricultural production [26,27,28].

2.2. P Losses

As a fundamental element of plant nutrition, P excess does not cause problems for the crop itself but exposes the environment to the risk of P leakage and the consequent eutrophication of water bodies [1,29]. Although we can consider transfer into the oceans a natural process resulting from erosion and runoff, it is nevertheless accelerated by human activities such as arable farming, concentrated animal husbandry, and direct anthropogenic discharges, with losses in the range of 19–31 Mt P year−1 [30]. Total P losses to European river basins and sea outlets are estimated to be around 100,000 t P year−1 [23]. In general, preventing nutrient losses is more beneficial in energy and economic terms than recycling [31].
Losses from agricultural soils occur in both dissolved and particulate forms, and their transport depends on the soil type, the extent of soil P accumulation, erosion vulnerability, and hydrological connectivity to the waterbody [32,33,34,35,36]. For instance, a negligible decrease in pH is enough for the mobilisation of significant quantities of P [37]. Several studies have shown the influence of catchment characteristics and changes in land use on water quality and the integrity of ecosystems downstream (Table 2).
Agricultural areas play an important role in P losses, as they are the main areas subject to erosion, which facilitates the loss of significant P flows. Their impacts are obvious not only on a local scale but also on a much larger scale [38,39,40,41]. Thus, the goal of eutrophication control would be more achievable if P concentrations in soils were kept at or below the recommended threshold values for improved fertiliser response [4,40,42,43,44,45,46], including strategies to mitigate the transfer of P by erosion [47].
Mockler et al. [48] calculated 0.39 kg ha−1 as the annual average value of P export to the Irish national territory, of which 51% comes from wastewater and 49% from grazing and agricultural land (0.19 kg ha−1). Van Dijk et al. [49] suggested that emissions from runoff and erosion to the hydrosphere from the 27 EU member countries account for 41% of total P losses. With over 191 million hectares of agricultural land in Europe, 0.084 Mt of P from runoff and erosion is leaving the system each year, values comparable with those estimated by a recent study by Palagon et al. [23].
Table
Table 2. General characteristics of the catchment area sorted by land use. The quantities of phosphorus lost from soils entering surface waters or the P content in the surface waters of the basin are also reported.
Table 2. General characteristics of the catchment area sorted by land use. The quantities of phosphorus lost from soils entering surface waters or the P content in the surface waters of the basin are also reported.
Catchments IDCoordinatesSoils aLand Use bMAP mm year−1Clay %OC b g kg−1pH aP Loss kg ha−1P Loss mg L−1Ref c
cereals
Robe (IR)53°41′32″ N 9°03′45″ WPZ, UMCPAH1150 19506.01.09 [50]
Wye (UK)52°03′16″ N 3°10′32″ WPZ, CMCMGFHP1000131325.50.52 [4]
Chesapeake (US)37°31′15″ N 76°06′18″ WAL, AC, LVCSWHDP89013255.00.84 [4]
Paimionjoki (FI)60°28′02″ N 22°40′56″ EGL, PZCLDA68035194.90.88 [4]
Odense (DK)55°13′00″ N 10°18′36″ ECM, LVCPAH58015176.50.75 [50]
Palma del Río (ES)37°41′ N 5°18′ WVRCDWLS57047157.21.07 [42]
Palma del Río (ES)37°41′ N 5°18′ WLVCDWS57022157.80.67 [42]
pasture
Neagh-Bann (IR)53°31′04″ N 6°43′34″ WCM, LVPPFAL80020306.70.16 [48]
North-West (IR)54°36′18″ N 8°01′15″ WPZ, CMPPF1100201305.40.21 [48]
Shannon (IR)53°16′30″ N 7°57′29″ WPZ, CMPPF75020506.20.16 [48]
West (IR)53°46′40″ N 9°04′34″ WPZ, GLPPF110022556.10.21 [48]
South-West (IR)51°56′51″ N 08°52′11″ WPZ, GLPPF85018705.30.20 [48]
South-East (IR)52°45′21″ N 6°54′28″ WPZ, GLPPF80021406.10.18 [48]
forestry
F26 (SE)57°13′45″ N 13°38′24″ EPZ, CMFAL10705604.3 0.12[41]
N33 (SE)56°36′01″ N 13°03′28″ ECM, LVFAL82021206.2 0.16[41]
N34 (SE)56°34′46″ N 13°03′45″ ECM, LVFAL82014256.8 0.10[41]
M36 (SE)56°08′36″ N 13°04′51″ ECM, FLFAL72026306.3 0.20[41]
M42 (SE)55°20′27″ N 13°48′04″ EFL, PZFAL71016506.4 0.15[41]
O18 (SE)58°26′42″ N 12°54′25″ EPZ, CMFAL66035404.5 0.50[41]
C6 (SE)59°42′48″ N 17°18′52″ EPZ CM,FAL62042654.8 0.21[41]
I28 (SE)57°30′14″ N 18°42′58″ EFL, CMFAL59020286.5 0.18[41]
U8 (SE)59°20′45″ N 16°33′33″ EPZ, CMFAL54050454.7 0.26[41]
E21 (SE)58°24′36″ N 15°20′57″ EPZ, CMFAL51016444.6 0.06[41]
Flakkensee Locknitz (DE)53°26′27″ N 14°13′24″ ECM, LVFCPAH55013217.10.27 [50]
Schuitenbeek (NL)52°15′07″ N 5°32′20″ EPZFMCFP780152651.59 [50]
a Soils: VR— Vertisols; Fl— Fluvisols; GL, Gleysols; PZ—Podzols; AL—Alisos; AC—Acrisols; LV—Luvisols; UM—Umbrisols; CM—Cambisols. The soil classification is according to the World Reference Base for Soil Resources (this information was obtained from SoilGrids.org platform, which contains soil information on a global scale), and any adaptations from other reference systems were made using a conversion table developed by Buol et al. (2006) [51]. b Land use: CLDA—cereal and a low animal density; CMGFHP—cereals and mixed grassland, fruit, hops, and potatoes; CSGHDP—corn, soybeans and wheat and a high density of poultry locally; CDWLS—cereals (durum wheat, linseed, and sunflower); CDWS—cereals (durum wheat and sunflower); FAL—forest and agriculture land; FM—forest and mire; FMCFP—forests, moors, cereals, fruits, and potatoes; CPAH—cereals, potatoes, and animal husbandry; FCPAH—forest, cereals, potatoes, and animal husbandry; PPF—pasture, peatlands, and forestry; PPFAL—pasture, forestry, peatlands, and arable land; c reference.

2.3. Estimated P by Pedotransfer Functions

Pedotransfer functions serve to predictively extrapolate certain unmeasured soil properties using measured data from soil surveys. Pedotransfer functions that use indicators are included in the software developed to be utilised directly at the farm level by farmers, calculating the seasonal need for nutrients that could be used to reduce the use of fertilisers and thus avoid P accumulation in soils. Such software was developed to calculate the seasonal demand for P and the best cost–benefit combination of commercial fertilisers [16]. In this way, farmers should have the information necessary to apply the required doses to increase the yield of their crops, gaining benefits in both economic and environmental terms thanks to the reduction of fertilisers used and consequent P loss. However, even if P concentrations in the soil are reduced to the agronomic optimum, it is not clear whether this would be sufficient to reduce P concentrations in the runoff enough to avoid eutrophication problems [52,53]. Based on the optimal soil P threshold test (STP), which provides information on the maximum P threshold required for optimal agricultural production on farms [25], Vadas et al. [54] used the Annual Phosphorus Loss Estimator (APLE) model to predict the impact of STP reductions and erosion control measures on the transfer of soil P contents (current and drawdown) and P transport (runoff and soil erosion) in three contrasting catchment areas.
On average, each year, about 90% of P flows to rivers, lakes, oceans, or non-agricultural land, so optimising soil management and the efficient use of P would reduce nutrient pollution in intercepting waterways [55]. Overall, livestock production contributes the most to total P releases into water bodies, and the phenomenon is magnified in areas where the soils are naturally submerged or by farming practices [56].

3. Technologies to Remove P from Water

Technologies developed to remove and recover P from P-rich waste streams, such as municipal wastewaters (5–25 mg total P L−1) [57], are basically of two types: physical–chemical, such as membrane filtration, precipitation, adsorption, ion exchange, or crystallisation, and biological processes (Table 3). These technologies target different P sources, using different engineering approaches that differ significantly in the P recycling rate, pollutant removal potential, product quality, environmental impact, and cost [58,59,60].
The scarcity of raw material coupled with environmental problems related to the overuse of phosphate fertilisers has also been considered. In addition to the point sources of P, such as phosphate rocks, non-point sources containing dissolved P, such as surface water, agricultural runoff channels, or surface rainwater, from which the needed P can be drawn to sustain global needs, are considered [48,61]. Though progress has been made using strategies for the general management of fertilisation and irrigation to decrease the amounts of P losses [62], these themselves, although smaller than before, continue to reach the receiving waters [63]. However, removing P from agricultural surface wastewaters and its reuse as fertiliser could only meet one-fourth of the annual European demand and at least 3% of the global demand for P fertilisers [64,65].

3.1. P Adsorption

As mentioned above, it is important to recover P from agricultural runoff channels, but because it is not easy to intercept in that context, it is necessary to capture P directly from watercourses, where its concentration is, therefore, low. One of the most suitable techniques to recover these low concentrations of P is physicochemical adsorption, a surface molecular interaction that occurs on contact between a solid phase (the adsorbent) and a fluid (liquid or gaseous) phase (the adsorbate). The adsorption process in a solution–adsorbate system occurs because of two factors: the affinity between a solute and solvent and a higher affinity between a solute and solid. The chemical species of the adsorbates establish chemical –physical interactions through Van der Waals forces or intermolecular chemical bonds with groups of adsorbents. The adsorption process, classified among the more advanced treatments, is suitable for the removal of suspended, dissolved, and colloidal forms still present in wastewater treatment plants. The adsorption of P ions depends on different adsorbent factors, such as the surface area, charge, and physicochemical properties of the solution, P concentration, temperature, pH, and presence of other competing ions or molecules [66,67,68]. The selectivity of an adsorbent, i.e., its ability to remove P preferentially from competing ions, is another factor in adsorption studies and depends on the type of interaction formed by the ions competing directly for the active sites of the adsorbent surface. In general, ions such as chloride and nitrate show little or no competition, while ions such as arsenate and silicate show high competition [69,70,71,72]. Phosphate adsorption usually reaches an optimal level when the pH promotes its electrostatic attraction to the adsorbent, i.e., when the pH of the solution is lower than that of the zero-charge point (ZPC) of the adsorbent, making it electropositive. Since several adsorbents have a ZPC near-neutral pH, optimal P adsorption is often in the acidic range [73,74,75,76,77,78,79].

3.2. P-Adsorbent Industrial Materials: “Grey Removal”

In the beginning, the circular economy and the possibility of recycling fertiliser elements, such as P, was not a research priority given the low cost of the materials. Studies on possible biosorbents started in the 1990s, intending, essentially, to remove metal ions, organic molecules, or dyes from wastewater [80]. Since these experiments also studied the behaviours of different anions, the extension of these findings to the phosphate ion is certainly plausible. Different materials have been used for P removal from waste streams through an adsorption mechanism [81,82]. The materials most used and reported in the literature have been wastes, residues, or by-products of the metallurgical industry sometimes modified (Table 4), “grey removal”. Cusack et al. [83] used adsorption to remove P from agricultural waters, employing bauxite residue, a sedimentary rock that is the source of aluminium, resulting in a potential low-cost adsorbent. They treated two freshwaters: low-P forest runoff (FR; pH 7.6 and 1 mg P L−1) and high-P dairy-soiled water (DSW; pH 7.8 and 11 mg P L−1). From the experiments conducted on three columns of different heights (20, 30, and 40 cm), bauxite residue had P removal capabilities in both the low and high ranges of P-concentrated waters (FR: 0.34 mg g−1 of P; DSW: 2.75 mg g−1 of P) due to the strong interaction between Al and orthophosphate anions. The estimated service times of the column media, based on the largest column studied, were 1.08 min g−1 for the FR and 0.28 min g−1 for the DSW.
Another high-volume by-product produced in the steel industry, blast furnace slag, was used to prepare a hydrated calcium silicate adsorbent (CSH) to remove phosphate from aqueous solutions. CSH showed a maximum P adsorption capacity of 53 mg g−1 in a solution with an initial P concentration of 13 mg L−1, at pH 7.0 and 25 °C. CSH showed excellent adsorption performance related to abundantly present Fe and Ca ions, even from phosphate solutions with a wide range of initial concentrations (2–26 mg L−1) and pH conditions (pH 3–9) [91].
Sellner et al. [90] conducted laboratory experiments on fixed bed columns with recycled steel chips of different sizes using alkaline solutions. It was found that adsorption was initially rapid, followed by a stable removal step with a contact time of 3 minutes and an initial P concentration of 10 mg L−1 (the desorption depended on the NaOH concentration). Kasak et al. [91] treated wastewater in submerged cells with an experimental horizontal filter filled with well-mineralised oil shale ash and peat. Comparing peat and oil shale ash, the latter removed 99% of the 22 mg L−1 of P present in the wastewater, whereas peat removed 63%. However, oil shale ash increased the pH value and the Ca2+ concentration in the runoff. Ostram and Davis [77] treated simulated rainwater with a 5 cm expanded shale aggregate, based on aluminium, and a psyllium binder (Plantago psyllium L., a herbaceous plant that contains aucubin glycoside, polyphenols, mucilage, and other substances, with high-permeability media mixture, HPMM). P retention increased as the simulated rainfall intensity decreased, and the pH was acid. Additionally, iron oxides have been widely used; examples include fly ash and red sludge modified by FeCl3 [94], where the adsorption capacity increased at pH 7. Another is akaganeite (FeO0.833(OH)1.167Cl0.167) from red sludge waste, which was not affected by the pH range of the solution tested (pH 5–9) due to the zero-charge point on the sorbent and the capacity to release hydrogen and chloride ions [87].
Liu and Hu [78] used a composite fibre composed of steel slag, zeolite, fly ash, and basalt (ZSFB) in a fixed bed reactor; the best P removal occurred at pH 4 and an initial concentration of 10 mg L−1. Afterwards, the fibre was regenerated with sulfuric acid. Zhou et al. [76] synthesised, characterised, and tested P removal/recovery in novel wastewater poly(vinyl alcohol)/sodium alginate/lanthanum hydroxide (PVA-SA-LH) hydrogel beads with an interpenetrating network (IPN) structure. They demonstrated a high P absorption capacity under acidic conditions due to the influence of the Lewis acid-base interactions between lanthanum hydroxide and phosphate. After five absorption–desorption cycles, the P absorption capacity of the absorbent remained above 75% of the first cycle. Many studies have tested the reusability of the adsorbent in 5 to 10 cycles.

4. P-Adsorbent Bio-Based Materials: “Green Removal”

All the studies above reported, based on the “grey” removal of P using adsorbents derived from by-products or the waste of the industries of steel, aluminium, or other material, or by their modifications, were carried out because of the availability of these materials and their chemical affinity with phosphate ions. Additionally, if often very efficient in P removal, P recovery by the adsorbent is carried out with strong acids or hydroxides. Therefore, many of these adsorbents, also meeting the criteria of a “circular economy” because the adsorbent is fully recovered and reusable several times, do not fit exactly with the concept of a “green treatment” [95]. On the other hand, relatively few works have described typical adsorption processes and the ability of adsorbents derived from agricultural waste to recover important anions such as P, arsenic (As), and chromium (Cr) (VI) anions. We identify the “green removal” agricultural waste products proposed as bio-based solutions to recover and reuse directly on farmland soils. Indeed, the feasibility of using the recovered materials in agriculture has not received much attention, however, due to their low cost, adsorbents from recovered agricultural materials deserve further study and still need major research. The great advantage in the removal of the P anions consists of the possibility, in the eventuality of a strong bind that does not allow for the recovery of P and reuse of the adsorbent, to use the product obtained as a fertiliser or a substrate. This opportunity, evidently, is not conceivable in the case of Cr or As. Table 5 lists some agricultural waste materials on which experiments have been conducted to evaluate their Cr(VI) and As(V) removal capabilities. As (V) and Cr (VI) are only considered because, in these oxidation states, they behave as anions, CrO42− and AsO43−, as well as P (PO43−), and thus, these three elements behave similarly in adsorption processes. The adsorption mechanisms of other PTEs (Pb, Fe, Zn, …) were not considered because their behaviours are essentially those of cations.
Biosorbents tested to recover Cr(VI) work under extremely acidic pH conditions (pH 2). Therefore, the development of this solution is a challenge from an economic and chemical point of view because maintaining a pH 2 in an actual plant is far from the concept of a “low-cost and green solution”. The same cannot be said for the biosorbents that have been tested to remove arsenate, which work in a pH range between 4 and 9, ensuring the promising performance of the biosorbent. Certainly, works such as those of Fox et al. [96], Gandhi et al. [97], and Asha et al. [98] will help in the development of new sustainable adsorbents for P removal, given the chemical affinity of the latter to arsenate ions.
Table
Table 5. The adsorption capacity of biosorbents that can remove anions Cr (VI) and As (V), and the conditions under which adsorption processes occur.
Table 5. The adsorption capacity of biosorbents that can remove anions Cr (VI) and As (V), and the conditions under which adsorption processes occur.
AdsorbentModificationPollutant RemovedAdsorption Capacity
mg g−1		Removal
%		pHT
°C		References
Ficus auriculata leavesUnmodifiedCr (VI) 94.32.030[99]
Milled olive stonesUnmodifiedCr (VI)2.3 2.0-[100]
Olive stone-Cr (VI)53.3 2.030[101]
Date pit-Cr (VI)82.6 2.030[101]
Cellulose derived by rice huskTreated with alkaline humic acidCr (VI)19.3 5.025[102]
Exhausted coffee wasteUnmodifiedCr (VI)686 3.025[103]
Raw rice strawUnmodifiedCr (VI)8.0 2.030[104]
Date palm trunkGraft with diethylenetriamine and triethylamineCr (VI)129.8 3.5 [105]
Sludge BiomassImmobilised with calcium alginateCr (VI)116.1 5.025[106]
Sugarcane bagasse pithImmobilised with Na-alginateCr (VI)52.8 2.025[107]
Black wattle tanninImmobilised with nanocelluloseCr (VI)104.6 2.025[108]
Cactus mucilageUnmodifiedAs (V)2.8 5.0–9.0-[96]
Powder of stem of Acacia nilotica UnmodifiedAs (V)50.8 4.0–7.0-[109]
Sorghum biomassUnmodifiedAs (V)2.8 5.0 [110]
Opuntia ficus indica fruit powderUnmodifiedAs (V) 85–926.0–7.0-[97]
Mucilage cactusUnmodifiedAs (V) 98 30[98]
Cactus mucilage (non-gelling extract)Mixed with sodium alginate and CaCl2As (V)97.1 [111]
Cactus mucilage (gelling extract)Mixed with sodium alginate and CaCl2As (V)101.6 [111]
To take into account the environmental sustainability of the adsorbent and its usefulness and easiness for reintroducing P into the environment, over recent years, researchers have proposed some adsorbents from waste materials of the agricultural sector with good properties that would enable sustainable P recovery, both environmentally and economically. These waste materials or by-products of agricultural processing, with or without further modification, are considered environmentally friendly, low-cost, and highly selective with high adsorption capacities [112,113,114,115,116,117]. The agricultural by-products that can be used to adsorb P, and then used as fertiliser or substrate are various: apple and black currant pulp, tea scraps, banana pith, sugar cane pith, coffee pulp [118,119,120,121], orange peel, potato peel, tangerine peel, onion peel, palm peel, hazelnut peel [2,121,122,123], exhausted coffee, corn cobs, rice hulls, corn straw and sawdust, rice straw and husk, sugarcane bagasse [124,125,126,127], almond shells, palm shell charcoal, hazelnut shells, peanut shells, eggshell or apricot kernels, and sunflower seed shells [128,129,130,131]. Numerous attempts have been made to develop new anion exchangers by grafting positively charged amino groups onto the polymer chains of agricultural residues, such as sugar cane bagasse [86], corn bracts [93,132], raw walnut wooden shells and raw almond wooden shells [133], and wheat straw [134]. These studies have shown that the absorption capacities of the charged materials were significantly increased compared to raw materials. The reuse of agricultural waste in the form of classic fertilisers (pellets, for example) is not yet sustainable, either economically or agronomically. The main problem is the elemental composition: all the elements of plant nutrition should be present and in balanced relative quantities [135,136].
A non-alternative but potentially synergistic approach, when P concentrations are high, is to precede the bio(ad)sorption phase with growing duckweed for protein [137].
Using vegetable material (corn bracts) modified by zirconium (Zr), Jiang et al. [79] observed an adsorption rate of organic P faster than that of inorganic phosphorus. Complexation and electrostatic attraction were probably the main adsorption mechanisms. The highest removal efficiency occurred at pH 2, highlighting the limitations of this material. Another limitation of this work was the pre-treatment with Zr; the corn bract by itself cannot remove P because it lacks anion-binding sites in its original surface structure. Hu et al. [84] anchored the Zr(IV) oxide nanoparticle on maize straw grafted with quaternary ammonium groups. The resulting composite Zr@MCS showed excellent performance for P removal in terms of adsorption capacity, selectivity, and regeneration, higher than that of raw maize straw and maize bract. Again, as with the corn bract of Jiang et al. [79], the treatment of corn straw with Zr oxides made it an excellent P adsorbent but, at the same time, was a limitation for the biosorbent itself since it could not be directly used as a fertiliser or soil conditioner. The strong selectivity of the adsorbent medium was also due to the high affinity between the Zr and P, especially at an acidic pH.
Other studies have been conducted in order to increase the sustainable recovery and reuse of waste resources by evaluating the potential use of compost in combination with locally available crop residues (Table 6). This can be considered a feasible option to improve the performance of the vermicomposting process judging from the aspects of organic matter destabilisation efficiency, microbial and earthworm activity, and the fertiliser value of the final product. This can help develop alternative and environmentally friendly economic strategies for the nutrient recovery of resource-rich crop residues [122,125,138,139,140,141,142].
Above all, as a final consideration, with the use of materials that provide nutrients to the soil, site-specific consideration should be given to their most suitable rates and types [143].
From this analysis of P recovery solutions, it is clear that the most promising feasibility lies in direct use as a soil amendment or composting. The cost-effectiveness of P recycling, independently from the availability of a waste, depends largely on the costs of transportation, storing, and management.
Table
Table 6. Alternative, environmentally friendly, economic strategies for nutrient recovery of resource-rich crop residues.
Table 6. Alternative, environmentally friendly, economic strategies for nutrient recovery of resource-rich crop residues.
ProductionBy-ProductP Content
% a		P Rem Min mgL−1 bP Ads Max mg g−1 cUseSuitability cExtra
Treatment d		References
BananaFruit 1.0Soil conditioner+++Compost[138]
Peels0.2 Soil conditioner+++Compost[139]
Stem0.5 Soil conditioner+++Vermicomposting[140]
Leaves0.2 Soil conditioner+++Vermicomposting[141]
Fruit and vegetables Soil conditioner+++Vermicomposting[142]
CloverCrop residues0.6 Soil conditioner+++ [144]
HazelnutHusk Soil conditioner+++Compost[125]
PoultryFeather waste0.5 Soil conditioner+++ [145]
Eggshell 180Soil conditioner+High temp[122]
PotatoPeel 15190Soil conditioner++Compost[122]
RiceHusk 1 Soil conditioner++High temp[146]
0.5 Soil conditioner++High temp[146]
12Soil conditioner+Low pH[147]
Hull6.0 Soil conditioner+Compost[148]
RiceHusk0.04 Soil conditioner+High temp[149]
300Soil conditioner+High pH[127]
AlmondShell 2 Soil conditioner+High pH[126]
SugarcaneMolasse0.304.0 Soil conditioner++ [133]
Bagasse10250Soil conditioner++High temp[150]
3.0Soil conditioner++P added[151]
Vinasse0.01 Irrigation+ [152]
SugarbeetRoot0.5 Energy, fertiliser+Digestion[153]
OrangePeel0.2 Fertiliser+++ [154]
PalmKernel shell 1 Fertiliser+High temp[123]
PeanutShell 30Fertiliser+High temp, low pH[131]
CoffeeGround exhausted0.2 Growth media+++ [155]
a P content range; b P removal min concentration; P adsorption maxima; c Suitability: +++ reasonable use at farm both economically and technologically, ++ economically sustainable use at farm, + reasonable use at farm technologically only; d Extra treatment, at least one further treatment is required for reuse in agriculture.

5. Conclusions

Current grey P adsorbents are based on waste materials from the steel industry, which ensure a high rate of P removal but do not allow for its direct reuse as fertiliser. Green P adsorbents are vegetable wastes; they are abundant, locally available, low-cost, and eco-sustainable, but the challenge is certainly their transport. A limitation to the reuse and recycling of agricultural by-products is seeking reusability at all costs, without evaluating the technical and economic feasibility; extra interventions are frequently proposed (i.e., applying high temperatures or adding expensive synthetic molecules to modify the pH). In general, the most promising feasibility is given by its direct use as a soil conditioner or by composting it as a by-product, as the only pre-treatment.
At the time of writing, rock P costs EUR 320 per tonne, while diammonium phosphate exceeds EUR 1000 per tonne, as the fertiliser end-user price. Recovering P from surficial water can cost as much as EUR 640 per ton, depending on the type of technique used. If cheap agricultural waste adsorbents were used, the cost-effectiveness of recycling P would be even more apparent, but would also need to take into account the availability of the waste, the cost of transport, and the possible cost of storing such waste.

Author Contributions

Conceptualization, F.S. and R.S.; methodology, F.S. and R.S.; formal analysis, N.A.; investigation, N.A.; data curation, N.A.; writing—original draft preparation, N.A., F.S. and R.S.; writing—review and editing, N.A., F.S. and R.S.; visualization, N.A.; supervision, F.S. and R.S.; project administration, N.A. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding. The APC was self-funded by the authors.

Data Availability Statement

All data are shown in the tables. The study did not report any further data.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Steffen, W.; Richardson, K.; Rockström, J.; Cornell, S.E.; Fetzer, I.; Bennett, E.M. Planetary boundaries: Guiding human development on a changing planet. Science 2015, 347, 1259855. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  2. Petruccioli, M.; Raviv, M.; Di Silvestro, R.; Dinelli, G. Agriculture and agro-industrial wastes, by-products, and wastewaters: Origin, characteristics, and potential in bio-based compounds production. Compr. Biotechnol. 2019, 6, 477–490. [Google Scholar] [CrossRef]
  3. Bindraban, P.S.; Dimkpa, C.O.; Pandey, R. Exploring phosphorus fertilizers and fertilization strategies for improved human and environmental health. Biol. Fertil. Soils 2020, 56, 299–317. [Google Scholar] [CrossRef] [Green Version]
  4. Withers, P.J.A.; Vadas, P.A.; Uusitalo, R.; Forber, K.J.; Hart, M.; Foy, R.H.; Delgado, A.; Dougherty, W.; Lilja, H.; Burkitt, L.L.; et al. A global perspective on integrated strategies to manage soil phosphorus status for eutrophication control without limiting land productivity. J. Environ. Qual. 2019, 48, 1234–1246. [Google Scholar] [CrossRef] [Green Version]
  5. Azam, H.M.; Alam, S.T.; Hasan, M.; Yameogo, D.D.S.; Kannan, A.D.; Rahman, A.; Kwon, M.J. Phosphorus in the environment: Characteristics with distribution and effects, removal mechanisms, treatment technologies, and factors affecting recovery as minerals in natural and engineered systems. Environ. Sci. Pollut. Res. 2019, 26, 20183–20207. [Google Scholar] [CrossRef] [PubMed]
  6. U.S. Geological Survey. Mineral Commodity Summaries. 2022. Available online: https://www.usgs.gov/centers/nmic/commodity-statistics-and-information (accessed on 16 November 2022).
  7. Manning, D.A.C.; Theodoro, S.H. Enabling food security through use of local rocks and minerals. Extr. Ind. Soc. 2020, 7, 480–487. [Google Scholar] [CrossRef]
  8. European Commission (EC). Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions. Consultative Communication on the Sustainable Use of Phosphorus. 2013. Available online: https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=celex:52013DC0517 (accessed on 16 November 2022).
  9. Cordell, D.; White, S. Sustainable phosphorus measures: Strategies and technologies for achieving phosphorus security. Agronomy 2013, 3, 86–116. [Google Scholar] [CrossRef] [Green Version]
  10. Canziani, R.; Di Cosmo, R. Stato dell’arte e potenzialità delle tecnologie di recupero del fosforo dai fanghi di depurazione. Ing. Dell’ambiente 2018, 5, 3. [Google Scholar] [CrossRef]
  11. Reta, G.; Dong, X.; Li, Z.; Su, B.; Hu, X.; Bo, H.; Yu, D.; Wan, H.; Liu, J.; Li, Y.; et al. Environmental impact of phosphate mining and beneficiation: Review. Int. J. Hydrogen Energy 2018, 2, 424–431. [Google Scholar] [CrossRef] [Green Version]
  12. Van Vuuren, D.P.; Bouwmana, A.F.; Beusen, A.H.W. Phosphorus demand for the 1970–2100 period: A scenario analysis of resource depletion. Glob. Environ. Change 2010, 20, 428–439. [Google Scholar] [CrossRef]
  13. IFA. Fertilizer Outlook 2014–2018. In Proceedings of the 82nd IFA Annual Conference, Sydney, Australia, 26–28 May 2014; pp. 1–7. [Google Scholar]
  14. Eurostat. Agri-Environmental Indicator-Mineral Fertiliser Consumption. 2022. Available online: https://ec.europa.eu/eurostat/databrowser/view/aei_fm_usefert/default/table?lang=en (accessed on 15 November 2022).
  15. Seleiman, M.F.; Santanen, A.; Mäkelä, P.S.A. Recycling sludge on cropland as fertilizer-Advantages and risks. Resour. Conserv. Recycl. 2020, 155, 104647. [Google Scholar] [CrossRef]
  16. Villalobos, F.J.; Delgado, A.; López-Bernal, Á.; Quemada, M. FertiliCalc: A Decision Support System for fertilizer management. Int. J. Plant Prod. 2019, 14, 299–308. [Google Scholar] [CrossRef]
  17. European Commission (EC). Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions on the 2017 List of Critical Raw Materials for the Europe. 2017. Available online: https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:52017DC0490 (accessed on 15 November 2022).
  18. Li, B.; Bicknell, K.B.; Renwick, A. Peak phosphorus, demand trends and implications for the sustainable management of phosphorus in China. Resour. Conserv. Recycl. 2019, 146, 316–328. [Google Scholar] [CrossRef]
  19. Vaccari, D.; Daneshgar, S.; Callegari, A.; Capodaglio, A.G. The potential phosphorus crisis: Resource conservation and possible escape technologies: A review. Resources 2018, 7, 37. [Google Scholar] [CrossRef] [Green Version]
  20. Martín-Hernandez, E.; Hu, Y.; Zavala, V.M.; Martín, M.; Ruiz-Mercado, G.J. Analysis of incentive policies for phosphorus recovery at livestock facilities in the Great Lakes area. Resour. Conserv. Recycl. 2022, 177, 105973. [Google Scholar] [CrossRef] [PubMed]
  21. Bhattacharya, A. Changing Climate and Resource Use Efficiency in Plants; Academic Press: Cambridge, MA, USA, 2018. [Google Scholar]
  22. Food and Agriculture Organization of the United Nations (FAO). Plant Nutrition for Food Security: A Guide for Integrated Nutrient Management; FAO Fertilizer and Plant Nutrition Bulletin 16 for Food and Agriculture Organization of the United Nations: Rome, Italy, 2006. [Google Scholar]
  23. Panagos, P.; Köninger, J.; Ballabio, C.; Liakos, L.; Muntwyler, A.; Borrelli, P.; Lugato, E. Improving the phosphorus budget of European agricultural soils. Sci. Total Environ. 2022, 853, 158706. [Google Scholar] [CrossRef]
  24. Withers, P.J.A.; Hodgkinson, R.A.; Rollett, A.; Dyer, C.; Dils, R.; Collins, A.L.; Bilsborrow, P.E.; Bailey, G.; Sylvester-Bradley, R. Reducing soil phosphorus fertility brings potential long-term environmental gains: A UK analysis. Environ. Res. Lett. 2017, 12, 063001. [Google Scholar] [CrossRef] [Green Version]
  25. Nawara, S.; van Dael, T.; Merckx, R.; Amery, F.; Elsen, A.; Odeurs, W.; Vandendriessche, H.; Mcgrathe, S.; Roisin, C.; Jouany, C.; et al. A comparison of soil tests for available phosphorus in long-term field experiments in Europe. Eur. J. Soil Sci. 2017, 68, 873–885. [Google Scholar] [CrossRef] [Green Version]
  26. Gourley, C.J.P.; Aarons, S.R.; Hannah, M.C.; Awty, I.M.; Dougherty, W.J.; Burkitt, L.L. Soil phosphorus, potassium, and sulphur excesses, regularities and heterogeneity in grazing-based dairy farms. Agric. Ecosyst. Environ. 2015, 201, 70–82. [Google Scholar] [CrossRef]
  27. International Plant Nutrition Institute (IPNI). Soil Test Levels in North America; International Plant Nutrition Institute: Peachtree Corners, GA, USA, 2015. [Google Scholar]
  28. Tóth, G.; Guicharnaud, R.A.; Tóth, B.; Hermann, T. Phosphorus levels in croplands of the European Union with implications for P fertilizer use. Eur. J. Agron. 2014, 55, 42–52. [Google Scholar] [CrossRef]
  29. Carpenter, S.R.; Bennett, E.M. Reconsideration of the planetary boundary for phosphorus. Environ. Res. Lett. 2011, 6, 1. [Google Scholar] [CrossRef]
  30. Compton, J.S.; Mallinson, D.J.; Glenn, C.R.; Filippelli, G.; Follmi, K.; Shields, G.; Zanin, Y. Variations in the global phosphorus cycle. Mar. Authigenesis Glob. Microb. 2000, 66, 21–33. [Google Scholar] [CrossRef] [Green Version]
  31. Cordell, D.; White, S. Life’s bottleneck: Sustaining the world’s phosphorus for a food secure future. Annu. Rev. Environ. Resour. 2014, 39, 161–188. [Google Scholar] [CrossRef]
  32. EEA. European Environment Agency, European Waters—Assessment of Status and Pressures. European Environment Agency, Copenhagen. 2012. Available online: https://www.eea.europa.eu/publications/european-waters-assessment-2012 (accessed on 16 November 2022).
  33. Liu, W.; Yao, L.; Wang, Z.; Xiong, Z.; Liu, G. Human land uses enhance sediment denitrification and N2O production in Yangtze lakes primarily by influencing lake water quality. Biogeosciences 2015, 12, 6059–6070. [Google Scholar] [CrossRef] [Green Version]
  34. Soranno, P.A.; Cheruvelil, K.S.; Wagner, T.; Webster, K.E.; Bremigan, M.T. Effects of land use on lake nutrients: The importance of scale, hydrologic connectivity, and region. PLoS ONE 2015, 10, e0135454. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  35. Schröder, J.J.; Schulte, R.P.O.; Creamer, R.E.; Delgado, A.; van Leeuwen, J.; Lehtinen, T.; Rutgers, M.; Spiegel, H.; Staes, J.; Tóth, G.; et al. The elusive role of soil quality in nutrient cycling: A review. Soil Use Manag. 2016, 32, 476–486. [Google Scholar] [CrossRef]
  36. Withers, P.J.A.; Bowes, M.J. Phosphorus the pollutant. In Phosphorus: Polluter and Resource of the Future: Removal and Recovery from Wastewater; Schaum, C., Ed.; IWA Publishing: London, UK, 2018; pp. 3–34. [Google Scholar] [CrossRef]
  37. Wollmann, I.; Möller, K. Increased phosphorus availability from sewage sludge ashes to maize in a crop rotation with clover. Soil Use Manag. 2022, 38, 1394–1402. [Google Scholar] [CrossRef]
  38. Fischer, P.; Pöthig, R.; Venohr, M. The degree of phosphorus saturation of agricultural soils in Germany: Current and future risk of diffuse P loss and implications for soil P management in Europe. Sci. Total Environ. 2017, 599–600, 1130–1139. [Google Scholar] [CrossRef]
  39. Latinopoulos, D.; Ntislidou, C.; Kagalou, I. Multipurpose plans for the sustainability of the Greek lakes: Emphasis on multiple stressors. Environ. Process. 2016, 3, 589–602. [Google Scholar] [CrossRef]
  40. Mavromati, E.; Kagalou, I.; Kemitzoglou, D.; Apostolakis, A.; Seferlis, M.; Tsiaoussi, V. Relationships among land use patterns, hydromorphological features and physicochemical parameters of surface waters: WFD lake monitoring in Greece. Environ. Process. 2018, 5, 139–151. [Google Scholar] [CrossRef]
  41. Sandström, S.; Futter, M.N.; Kyllmar, K.; Bishop, K.; O’Connell, D.W.; Djodjic, F. Particulate phosphorus and suspended solids losses from small agricultural catchments: Links to stream and catchment characteristics. Sci. Total Environ. 2020, 711, 134616. [Google Scholar] [CrossRef] [PubMed]
  42. Díaz, I.; del Campillo, M.C.; Barrón, V.; Torrent, J.; Delgado, A. Phosphorus losses from two representative small catchments in the Mediterranean part of Spain. J. Soils Sediments 2013, 13, 1369–1377. [Google Scholar] [CrossRef]
  43. Ekholm, P.; Rankinen, K.; Rita, H.; Räike, A.; Sjöblom, H.; Raateland, A.; Vesikko, L.J.E.; Bernal, C.; Taskinen, A. Phosphorus and nitrogen fluxes carried by 21 Finnish agricultural rivers in 1985–2006. Environ. Monit. Assess. 2015, 187, 216. [Google Scholar] [CrossRef] [PubMed]
  44. Jarvie, H.P.; Withers, P.J.A.; Hodgkinson, R.; Bates, A.; Neal, M.; Wickham, H.D.; Harman, S.A.; Armstrong, L. Influence of rural land use on streamwater nutrients and their ecological significance. J. Hydrol. 2008, 350, 166–186. [Google Scholar] [CrossRef]
  45. Tattari, S.; Koskiaho, J.; Kosunen, M.; Lepistö, A.; Linjama, J.; Puustinen, M. Nutrient loads from agricultural and forested areas in Finland from 1981 up to 2010: Can the efficiency of undertaken water protection measures seen? Environ. Monit. Assess. 2017, 189, 95. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  46. Vuorenmaa, J.; Rekolainen, S.; Lepistö, A.; Kenttämies, K.; Kauppila, P. Losses of nitrogen and phosphorus from agricultural and forested areas in Finland during the 1980s and 1990s. Environ. Monit. Assess. 2002, 76, 213–248. [Google Scholar] [CrossRef]
  47. Dodd, R.J.; Sharpley, A.N. Conservation practice effectiveness and adoption: Unintended consequences and implications for sustainable phosphorus management. Nutr. Cycl. Agroecosyst. 2016, 104, 373–392. [Google Scholar] [CrossRef]
  48. Mockler, E.M.; Deakin, J.; Archbold, M.; Gill, L.; Daly, D.; Bruen, M. Sources of nitrogen and phosphorus emissions to Irish rivers and coastal waters: Estimates from a nutrient load apportionment framework. Sci. Total Environ. 2017, 601–602, 326–339. [Google Scholar] [CrossRef] [PubMed]
  49. Van Dijk, K.C.; Lesschen, J.P.; Oenema, O. Phosphorus flows and balances of the European Union Member States. Sci. Total Environ. 2016, 542, 1078–1093. [Google Scholar] [CrossRef] [PubMed]
  50. De Klein, J.J.M.; Koelmans, A.A. Quantifying seasonal export and retention of nutrients in West European lowland rivers at catchment scale. Hydrol. Process. 2011, 25, 2102–2111. [Google Scholar] [CrossRef]
  51. Buol, S.W.; Certini, G.; Scalenghe, R. Appendix: Naming soils and soil horizons. In Soils: Basic Concepts and Future Challenges; Certini, G., Scalenghe, R., Eds.; Cambridge University Press: Cambridge, UK, 2006; pp. 265–275. [Google Scholar] [CrossRef] [Green Version]
  52. Cassidy, R.; Doody, D.G.; Watson, C.J. Impact of legacy soil phosphorus on losses in drainage and overland flow from grazed grassland soils. Sci. Total Environ. 2017, 575, 474–484. [Google Scholar] [CrossRef]
  53. Duncan, E.W.; King, K.W.; Williams, M.R.; LaBarge, G.; Pease, L.A.; Smith, D.R.; Fausey, N.R. Linking soil phosphorus to dissolved phosphorus losses in the Midwest. Agric. Environ. Lett. 2017, 2, 170004. [Google Scholar] [CrossRef] [Green Version]
  54. Vadas, P.A.; Fiorellino, N.M.; Coale, F.J.; Kratochvil, R.; Mulkey, A.S.; McGrath, J.M. Estimating legacy soil phosphorus impacts on phosphorus loss in the Chesapeake Bay watershed. J. Environ. Qual. 2018, 47, 480–486. [Google Scholar] [CrossRef] [PubMed]
  55. Gilbert, N. Environment: The disappearing nutrient. Nature 2009, 461, 716–718. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  56. Liu, D.; Bai, L.; Li, X.; Zhang, Y.; Qiao, Q.; Lu, Z.; Liu, J. Spatial characteristics and driving forces of anthropogenic phosphorus emissions in the Yangtze River. Resour. Conserv. Recycl. 2022, 176, 105937. [Google Scholar] [CrossRef]
  57. Henze, M.; van Loosdrecht, M.C.M.; Ekama, G.A.; Brdjanovic, D. Biological Wastewater Treatment: Principles, Modeling, and Design; IWA Publishing: London, UK, 2008. [Google Scholar] [CrossRef] [Green Version]
  58. Di Capua, F.; de Sario, S.; Ferraro, A.; Petrella, A.; Race, M.; Pirozzi, F.; Fratino, U.; Spasiano, D. Phosphorous removal and recovery from urban wastewater: Current practices and new directions. Sci. Total Environ. 2022, 823, 153750. [Google Scholar] [CrossRef] [PubMed]
  59. Ehama, M.; Hashihama, F.; Kinouchi, S.; Kanda, J.; Saito, H. Sensitive determination of total particulate phosphorus and particulate inorganic phosphorus in seawater using liquid waveguide spectrophotometry. Talanta 2016, 153, 66–70. [Google Scholar] [CrossRef]
  60. Egle, L.; Rechberger, H.; Krampe, J.; Zessner, M. Phosphorus recovery from municipal wastewater: An integrated comparative technological, environmental and economic assessment of P recovery technologies. Sci. Total Environ. 2016, 571, 522–542. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  61. Malagó, A.; Bouraoui, F.; Grizzetti, B.; De Roo, A. Modelling nutrient fluxes into the Mediterranean Sea. J. Hydrol. Reg. Stud. 2019, 22, 100592. [Google Scholar] [CrossRef] [PubMed]
  62. Martinez, J.; Pellerin, S. Optimizing N and P recycling from organic amendments via agroecological incentives and concep–s-scope for further developments. Soil Use Manag. 2016, 32, 64–72. [Google Scholar] [CrossRef]
  63. Xia, Y.; Zhang, M.; Tsang, D.C.W.; Geng, N.; Lu, D.; Zhu, L.; Igalavithana, A.D.; Dissanayake, P.D.; Rinklebe, J.; Yang, X.; et al. Recent advances in control technologies for non-point source pollution with nitrogen and phosphorous from agricultural runoff: Current practices and future prospects. Appl. Biol. Chem. 2020, 63, 8. [Google Scholar] [CrossRef]
  64. Bouwman, L.; Goldewijk, K.K.; Van Der Hoek, K.W.; Beusen, A.H.W.; Van Vuuren, D.P.; Willems, J.; Rufino, M.C.; Stehfest, E. Exploring global changes in nitrogen and phosphorus cycles in agriculture induced by livestock production over the 1900–2050 period. Proc. Natl. Acad. Sci. USA 2013, 110, 21195. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  65. Fertilizers Europe. Fertilizers Europe Annual Overview 2019/2020; Fertilizers Europe: Brussels, Belgium, 2020. [Google Scholar]
  66. Mia, S.; Dijkstra, F.A.; Singh, B. Aging induced changes in bioc’ar’s functionality and adsorption behavior for phosphate and ammonium. Environ. Sci. Technol. 2017, 51, 8359–8367. [Google Scholar] [CrossRef]
  67. Weng, L.; Van Riemsdijk, W.H.; Hiemstra, T. Factors controlling phosphate interaction with iron oxides. J. Environ. Qual. 2012, 41, 628–635. [Google Scholar] [CrossRef]
  68. Zhu, L.; Wang, Z.; Shu, Q.; Takala, J.; Hiltunen, E.; Feng, P.; Yuan, Z. Nutrient removal and biodiesel production by integration of freshwater algae cultivation with piggery wastewater treatment. Water Res. 2013, 47, 4294–4302. [Google Scholar] [CrossRef] [PubMed]
  69. Lu, J.; Liu, H.; Liu, R.; Zhao, X.; Sun, L.; Qu, J. Adsorptive removal of phosphate by a nanostructured FeeAleMn trimetal oxide adsorbent. Powder Technol. 2013, 233, 146–154. [Google Scholar] [CrossRef]
  70. Xie, F.; Wu, F.; Liu, G.; Mu, Y.; Feng, C.; Wang, H.; Giesy, J.P. Removal of phosphate from eutrophic lakes through adsorption by in situ formation of magnesium hydroxide from diatomite. Environ. Sci. Technol. 2014, 48, 582–590. [Google Scholar] [CrossRef]
  71. Zhang, B.; Wang, L.; Riddicka, B.A.; Li, R.; Able, J.R.; Boakye-Boaten, N.A.; Shahbazi, A. Sustainable production of algal biomass and biofuels using swine wastewater in North Carolina, US. Sustainability 2016, 8, 477. [Google Scholar] [CrossRef]
  72. Kumar, P.S.; Korving, L.; van Loosdrecht, M.C.M.; Witkamp, G.J. Adsorption as a technology to achieve ultra-low concentrations of phosphate: Research gaps and economic analysis. Water Res. X 2019, 4, 100029. [Google Scholar] [CrossRef]
  73. Wen, Z.; Zhang, Y.; Dai, C. Removal of phosphate from aqueous solution using nanoscale zerovalent iron (nZVI). Colloids Surf. A Physicochem. Eng. Asp. 2014, 457, 433–440. [Google Scholar] [CrossRef]
  74. Fang, L.; Wu, B.; Lo, I.M.C. Fabrication of silica-free superparamagnetic ZrO2@Fe3O4 with enhanced phosphate recovery from sewage: Performance and adsorption mechanism. Chem. Eng. J. 2017, 319, 258–267. [Google Scholar] [CrossRef]
  75. He, Y.; Lin, H.; Dong, Y.; Wang, L. Preferable adsorption of phosphate using lanthanum-incorporated porous zeolite: Characteristics and mechanism. Appl. Surf. Sci. 2017, 426, 995–1004. [Google Scholar] [CrossRef]
  76. Zhou, A.; Zhu, C.; Chen, W.; Wan, J.; Tao, T.; Zhang, T.C.; Xie, P. Phosphorus recovery from water by lanthanum hydroxide embedded interpenetrating network poly (vinyl alcohol)/sodium alginate hydrogel beads. Colloids Surf. A 2018, 554, 237–244. [Google Scholar] [CrossRef]
  77. Ostrom, T.K.; Davis, A.P. Evaluation of an enhanced treatment media and permeable pavement base to remove stormwater nitrogen, phosphorus, and metals under simulated rainfall. Water Res. 2019, 166, 115071. [Google Scholar] [CrossRef]
  78. Liu, Y.; Hu, X. Kinetics and thermodynamics of efficient phosphorus removal by a composite fiber. Appl. Sci. 2019, 9, 2220. [Google Scholar] [CrossRef] [Green Version]
  79. Jiang, Y.; Chen, Y.; Du, Q.; Shi, J. Adsorption of different forms of phosphorus on modified corn bracts. Water Environ. Res. 2019, 91, 748–755. [Google Scholar] [CrossRef]
  80. Wang, L.; Rinklebe, J.; Tack, F.M.G.; Hou, D. A review of green remediation strategies for heavy metal contaminated soil. Soil Use Manag. 2021, 37, 936–963. [Google Scholar] [CrossRef]
  81. Arenas-Montaño, V.; Fenton, O.; Moore, B.; Healy, M.G. Evaluation of the fertiliser replacement value of phosphorus-saturated filter media. J. Clean. Prod. 2021, 291, 125943. [Google Scholar] [CrossRef]
  82. Gubernat, S.; Masłoń, A.; Czarnota, J.; Koszelnik, P. Reactive materials in the removal of phosphorus compounds from wastewater-a review. Materials 2020, 13, 3377. [Google Scholar] [CrossRef]
  83. Cusack, P.; Callery, O.; Courtney, R.; Ujaczki, E.; O’Donoghuef, L.M.T.; Healy, M.G. The use of rapid, small-scale column tests to determine the efficiency of bauxite residue as a low-cost adsorbent in the removal of dissolved reactive phosphorus from agricultural waters. J. Environ. Manag. 2019, 241, 273–283. [Google Scholar] [CrossRef]
  84. Hu, Y.; Du, Y.; Nie, G.; Zhu, T.; Ding, Z.; Wang, H.; Zhang, L.; Xu, Y. Selective and efficient sequestration of phosphate from waters using reusable nano-Zr(IV) oxide impregnated agricultural residue anion exchanger. Sci. Total Environ. 2020, 700, 134999. [Google Scholar] [CrossRef] [PubMed]
  85. Li, C.; Yang, H.; Li, Y.; Cheng, L.; Zhang, M.; Zhang, L.; Wang, W. Novel bioconversions of municipal effluent and CO2 into protein riched Chlorella vulgaris biomass. Bioresour. Technol. 2013, 132, 171–177. [Google Scholar] [CrossRef] [PubMed]
  86. Shang, Y.; Guo, K.; Jiang, P.; Xu, X.; Gao, B. Adsorption of phosphate by the cellulose-based biomaterial and its sustained release of laden phosphate in aqueous solution and soil. Int. J. Biol. Macromol. 2018, 109, 524–534. [Google Scholar] [CrossRef]
  87. Pepper, R.A.; Couperthwaite, S.J.; Millar, G.J. Re-use of waste red mud: Production of a Functional iron oxide adsorbent for removal of phosphorous. J. Water Process Eng. 2018, 25, 138–148. [Google Scholar] [CrossRef] [Green Version]
  88. de Alva, M.S.; Pabello, V.M.L.; Ledesma, M.T.O.; Gómez, M.J.C. Carbon, nitrogen, and phosphorus removal, and lipid production by three saline microalgae grown in synthetic wastewater irradiated with different photon fluxes. Algal Res. 2018, 34, 97–103. [Google Scholar] [CrossRef]
  89. Wong, P.Y.; Cheng, K.Y.; Kaksonen, A.H.; Sutton, D.C.; Ginige, M.P. A novel post denitrification configuration for phosphorus recovery using polyphosphate accumulating organisms. Water Res. 2013, 47, 6488–6495. [Google Scholar] [CrossRef]
  90. Sellner, B.M.; Hua, G.; Ahiablame, L.M. Fixed bed column evaluation of phosphate adsorption and recovery from aqueous solutions using recycled steel byproducts. J. Environ. Manag. 2019, 233, 595–602. [Google Scholar] [CrossRef]
  91. Kuwahara, Y.; Yamashita, H. Phosphate removal from aqueous solutions using calcium silicate hydrate prepared from blast furnace slag. ISIJ Int. 2017, 57, 1657–1664. [Google Scholar] [CrossRef] [Green Version]
  92. Kasak, K.; Mander, U.; Truu, J.; Truu, M.; Järveoja, J.; Maddison, M.; Teemusk, A. Alternative filter material removes phosphorus and mitigates greenhouse gas emission in horizontal subsurface flow filters for wastewater treatment. Ecol. Eng. 2015, 77, 242–249. [Google Scholar] [CrossRef]
  93. Banu, H.A.T.; Karthikeyan, P.; Meenakshi, S. Comparative studies on revival of nitrate and phosphate ions using quaternized corn husk and jackfruit peel. Bioresour. Technol. Rep. 2019, 8, 100331. [Google Scholar] [CrossRef]
  94. Wang, Y.; Yu, Y.; Li, H.; Shen, C. Comparison study of phosphorus adsorption on different waste solids: Fly ash, red mud and ferric–alum water treatment residues. J. Environ. Sci. 2016, 50, 79–86. [Google Scholar] [CrossRef] [PubMed]
  95. Altamira-Algarra, B.; Puigagut, J.; Day, J.W.; Mitsch, W.J.; Vymazal, J.; Hunter, R.G.; García, J. A review of technologies for closing the P loop in agriculture runoff: Contributing to the transition towards a circular economy. Ecol. Eng. 2022, 177, 106571. [Google Scholar] [CrossRef]
  96. Fox, D.I.; Pichler, T.; Yeh, D.H.; Alcantar, N.A. Removing heavy metals in water: The interaction of Cactus mucilage and arsenate (As (V)). Environ. Sci. Technol. 2012, 46, 4553–4559. [Google Scholar] [CrossRef]
  97. Gandhi, N.; Sirisha, D.; Sekhar, K.B.C. Biodepollution of paint manufacturing industry waste-water containing chromium by using coagulation process. J. Arts Sci. Commer. 2013, 4, 110–118. [Google Scholar]
  98. Asha, S.; Tabitha, C.; Himabindu, N.; Kumar, R.B. Efficiency of Opuntia ficus indica (L.) Mill. In removal of chromium from synthetic solution. Res. J. Pharm. Biol. Chem. Sci. 2014, 5, 1244–1251. [Google Scholar]
  99. Rangabhashiyam, S.; Selvaraju, N. Evaluation of the biosorption potential of a novel Caryota urens inflorescence waste biomass for the removal of hexavalent chromium from aqueous solutions. J. Taiwan Inst. Chem. Eng. 2015, 47, 59–70. [Google Scholar] [CrossRef]
  100. Amar, M.B.; Walha, K.; Salvadó, V. Evaluation of Olive Stones for Cd(II), Cu(II), Pb(II) and Cr(VI) Biosorption from Aqueous Solution: Equilibrium and Kinetics. Int. J. Environ. Res. 2020, 14, 193–204. [Google Scholar] [CrossRef]
  101. Mangwandi, C.; Kurniawan, T.A.; Albadarin, A.B. Comparative biosorption of chromium (VI) using chemically modified date pits (CM-DP) and olive stone (CMOS): Kinetics, isotherms and influence of co-existing ions. Chem. Eng. Res. Des. 2020, 156, 251–262. [Google Scholar] [CrossRef]
  102. Basu, H.; Saha, S.; Mahadevan, I.A.; Pimple, M.V.; Singhal, R.K. Humic acid coated cellulose derived from rice husk: A novel biosorbent for the removal of Ni and Cr. J. Water Process Eng. 2019, 32, 100892. [Google Scholar] [CrossRef]
  103. Fiol, N.; Escudero, C.; Villaescusa, I. Chromium sorption and Cr(VI) reduction to Cr(III) by grape stalks and yohimbe bark. Bioresour. Technol. 2008, 99, 5030–5036. [Google Scholar] [CrossRef]
  104. Elmolla, E.S.; Hamdy, W.; Kassem, A.; Abdel Hady, A. Comparison of different rice straw based adsorbents for chromium removal from aqueous solutions. Desalin. Water Treat. 2016, 57, 6991–6999. [Google Scholar] [CrossRef]
  105. Yadav, S.K.; Sinha, S.; Singh, D.K. Chromium(VI) removal from aqueous solution and industrial wastewater by modified date palm trunk. Environ. Prog. Sustain. Energy 2015, 34, 452–460. [Google Scholar] [CrossRef]
  106. Ramteke, L.P.; Gogate, P.R. Removal of copper and hexavalent chromium using immobilized modified sludge biomass-based adsorbent. Clean Soil Air Water 2016, 44, 1051–1065. [Google Scholar] [CrossRef]
  107. Ullah, I.; Nadeem, R.; Iqbal, M.; Manzoor, Q. Biosorption of chromium onto native and immobilized sugarcane bagasse waste biomass. Ecololog. Eng. 2013, 60, 99–107. [Google Scholar] [CrossRef]
  108. Xu, Q.; Wang, Y.; Jin, L.; Wang, Y.; Qin, M. Adsorption of Cu (II), Pb (II) and Cr (VI) from aqueous solutions using black wattle tannin-immobilized nanocellulose. J. Hazard. Mater. 2017, 339, 91–99. [Google Scholar] [CrossRef] [PubMed]
  109. Baig, J.A.; Kazi, T.G.; Shah, A.Q.; Kandhro, G.A.; Afridi, H.I.; Khan, S.; Kolachi, N.F. Biosorption studies on powder of stem of Acacia nilotica: Removal of arsenic from surface water. J. Hazard. Mater. 2010, 178, 941–948. [Google Scholar] [CrossRef] [PubMed]
  110. Haque, N.M.; Morrison, G.M.; Perrusquia, G.; Gutierrez, M.; Aguilera, A.F.; Cano-Aguilera, I.; Gardea-Torresdey, J.L. Characteristics of arsenic adsorption to sorghum biomass. J. Hazard. Mater. 2007, 145, 30–35. [Google Scholar] [CrossRef]
  111. Vecino, X.; Devesa-Rey, R.; de Lima Stebbins, D.M.; Moldes, A.B.; Cruz, J.M.; Alcantar, N.A. Evaluation of a cactus mucilage biocomposite to remove total arsenic from water. Environ. Technol. Innov. 2016, 6, 69–79. [Google Scholar] [CrossRef] [Green Version]
  112. Alqadami, A.A.; Naushad, M.; Abdalla, M.A.; Ahamad, T.; ALOthman, Z.A.; Alshehri, S.M.; Ghfar, A.A. Efficient removal of toxic metal ions from wastewater using a recyclable nanocomposite: A study of adsorption parameters and interaction mechanism. J. Clean. Prod. 2017, 156, 426–436. [Google Scholar] [CrossRef]
  113. Shahat, A.; Awual, M.R.; Naushad, M. Functional ligand anchored nanomaterial based facial adsorbent for cobalt (II) detection and removal from water samples. Chem. Eng. J. 2015, 271, 155–163. [Google Scholar] [CrossRef]
  114. Mezenner, N.Y.; Bensmaili, A. Kinetics and thermodynamic study of phosphate adsorption on iron hydroxide-eggshell waste. Chem. Eng. J. 2009, 147, 87–96. [Google Scholar] [CrossRef]
  115. Xue, Y.; Hou, H.; Zhu, S. Characteristics and mechanisms of phosphate adsorption onto basic oxygen furnace slag. J. Hazard. Mater. 2009, 162, 973–980. [Google Scholar] [CrossRef] [PubMed]
  116. Yuan, X.; Bai, C.; Xia, W.; Xie, B.; An, J. Phosphate adsorption characteristics of wasted low-grade iron ore with phosphorus used as natural adsorbent for aqueous solution. Desalination Water Treat. 2015, 54, 3020–3030. [Google Scholar] [CrossRef]
  117. Zeng, L.; Li, X.; Liu, J. Adsorptive removal of phosphate from aqueous solutions using iron oxide tailings. Water Res. 2004, 38, 1318–1326. [Google Scholar] [CrossRef] [PubMed]
  118. Bailey, S.E.; Olin, T.J.; Bricka, R.M.; Adrian, D.D. A review of potential low-cost sorbents for heavy metals. Water Res. 1999, 33, 2469–2479. [Google Scholar] [CrossRef]
  119. Berecha, G.; Lemessa, F.; Wakjira, M. Exploring the suitability of coffee pulp compost as growth media substitute in greenhouse production. Int. J. Agric. Res. 2011, 6, 255–267. [Google Scholar] [CrossRef] [Green Version]
  120. Hernández, D.; Sánchez, J.E.; Yamasaki, K. () A simple procedure for preparing substrate for Pleurotus ostreatus cultivation. Bioresour. Technol. 2003, 90, 145–150. [Google Scholar] [CrossRef]
  121. Laufenberg, G.; Kunz, B.; Nystroem, M. Transformation of vegetable waste into value added products: (A) the upgrading concept; (B) practical implementations. Bioresour. Technol. 2003, 87, 167–198. [Google Scholar] [CrossRef] [PubMed]
  122. Quisperima, A.; Pérez, S.; Flórez, E.; Acelas, N. Valorization of potato peels and eggshells wastes: Ca-biocomposite to remove and recover phosphorus from domestic wastewater. Bioresour. Technol. 2022, 343, 126106. [Google Scholar] [CrossRef]
  123. Akinbile, C.O.; Ikuomola, B.T.; Olanrewaju, O.O.; Babalola, T.E. Assessing the efficacy of Azolla pinnata in four different wastewater treatment for agricultural re-use: A case history. Sustain. Water Resour. Manag. 2019, 5, 1009–1015. [Google Scholar] [CrossRef]
  124. González Bautista, E.; Gutierrez, E.; Dupuy, N.; Gaime-Perraud, I.; Ziarelli, F.; Farnet da Silva, A.M. Pre-treatment of a sugarcane bagasse-based substrate prior to saccharification: Effect of coffee pulp and urea on laccase and cellulase activities of Pycnoporus sanguineus. J. Environ. Manag. 2019, 239, 178–186. [Google Scholar] [CrossRef]
  125. Ozdemir, S.; Dede, O.H.; Yaqub, M. Assessment of Long-Term Nutrient Effective Waste-Derived Growth Media for Ornamental Nurseries. Waste Biomass Valorization 2017, 8, 2663–2671. [Google Scholar] [CrossRef]
  126. Sharmin, N.; Sabatini, D.A.; Butler, E.C. Phosphorus recovery and reuse using calcium-silicate hydrate made from rice husk. J. Environ. Chem. Eng. 2021, 147, 04021015. [Google Scholar] [CrossRef]
  127. Xiong, Q.; Wu, X.; Lv, H.; Liu, S.; Hou, H.; Wu, X. Influence of rice husk addition on phosphorus fractions and heavy metals risk of biochar derived from sewage sludge. Chemosphere 2021, 280, 130566. [Google Scholar] [CrossRef]
  128. Imamoglu, M.; Tekir, O. Removal of copper II and lead II ions from aqueous solutions by adsorption on activated carbon from a new precursor hazelnut husks. Desalination 2008, 228, 108–113. [Google Scholar] [CrossRef]
  129. Kobya, M.; Demirbas, E.; Ince, M. Absorption of heavy metal ions from aqueous solutions by activated carbon prepared from apricot stones. Bioresour. Technol. 2005, 96, 1518–1521. [Google Scholar] [CrossRef] [PubMed]
  130. Wilson, K.; Yang, H.; Seo, C.W.; Marshall, W.E. Select Metal adsorption by activated carbon made from peanut shells. Bioresour. Technol. 2006, 97, 2266–2270. [Google Scholar] [CrossRef]
  131. Fang, L.; Li, J.; Donatello, S.; Cheeseman, C.R.; Poon, C.S.; Tsang, D.C.W. Use of Mg/Ca modified biochars to take up phosphorus from acid-extract of incinerated sewage sludge ash (ISSA) for fertilizer application. J. Clean. Prod. 2020, 244, 118853. [Google Scholar] [CrossRef]
  132. Wang, C.; Wu, Y.; Bai, L.; Zhao, Y.; Yan, Z.; Jiang, H.; Liu, X. Recycling of drinking water treatment residue as an additional medium in columns for effective P removal from eutrophic surface water. J. Environ. Manag. 2018, 217, 363–372. [Google Scholar] [CrossRef]
  133. Faraji, B.; Zarabi, M.; Kolahchi, Z. Phosphorus removal from aqueous solution using modified walnut and almond wooden shell and recycling as soil amendment. Environ. Monit. Assess. 2020, 192, 373. [Google Scholar] [CrossRef] [PubMed]
  134. Xu, X.; Gao, B.; Wang, W.; Yue, Q.; Wang, Y.; Ni, S. Adsorption of phosphate from aqueous solutions onto modified wheat residue: Characteristics, kinetic and column studies. Colloids Surf. B Biointerfaces 2009, 70, 46–52. [Google Scholar] [CrossRef]
  135. Brod, E.; Toven, K.; Haraldsen, T.K.; Krogstad, T. Unbalanced nutrient ratios in pelleted compound recycling fertilizers. Soil Use Manag. 2018, 34, 18–27. [Google Scholar] [CrossRef]
  136. Müller-Stöver, D.S.; Jakobsen, I.; Grønlund, M.; Rolsted, M.M.M.; Magid, J.; Hauggaard-Nielsen, H. Phosphorus bioavailability in ash from straw and sewage sludge processed by low-temperature biomass gasification. Soil Use Manag. 2018, 34, 9–17. [Google Scholar] [CrossRef]
  137. Roman, B.; Brennan, R.A. A beneficial by-product of ecological wastewater treatment: An evaluation of wastewater-grown duckweed as a protein supplement for sustainable agriculture. Ecol. Eng. 2019, 142, 100004. [Google Scholar] [CrossRef]
  138. Lim, S.L.; Wu, T.Y.; Sim, E.Y.S.; Lim, P.N.; Clarke, C. Biotransformation of rice husk into organic fertilizer through vermicomposting. Ecol. Eng. 2012, 41, 60–64. [Google Scholar] [CrossRef]
  139. Kalemelawa, F.; Nishihara, E.; Endo, T.; Ahmad, Z.; Yeasmin, R.; Tenywa, M.M.; Yamamoto, S. An evaluation of aerobic and anaerobic composting of banana peels treated with different inoculums for soil nutrient replenishment. Bioresour. Technol. 2012, 126, 375–382. [Google Scholar] [CrossRef]
  140. Khatua, C.; Sengupta, S.; Balla, V.K.; Kundu, B.; Chakraborti, A.; Tripathi, S. Dynamics of organic matter decomposition during vermicomposting of banana stem waste using Eisenia fetida. Waste Manag. 2018, 79, 287–295. [Google Scholar] [CrossRef] [PubMed]
  141. Mago, M.; Yadav, A.; Gupta, R.; Garg, V.K. Management of banana crop waste biomass using vermicomposting technology. Bioresour. Technol. 2021, 326, 124742. [Google Scholar] [CrossRef] [PubMed]
  142. Li, W.; Bhat, S.A.; Li, J.; Cui, G.; Wei, Y.; Yamada, T.; Li, F. Effect of excess activated sludge on vermicomposting of fruit and vegetable waste by using novel vermireactor. Bioresour. Technol. 2020, 302, 122816. [Google Scholar] [CrossRef] [PubMed]
  143. Withers, P.J.A.; Flynn, N.J.; Warren, G.P.; Taylor, M.; and Chambers, B.J. Sustainable management of biosolid phosphorus: A field study. Soil Use Manag. 2016, 32, 54–63. [Google Scholar] [CrossRef]
  144. Torma, S.; Vilček, J.; Lošák, T.; Kužel, S.; Martensson, A. Residual plant nutrients in crop residues—An important resource. Acta Agric. Scand. Sect. B—Soil Plant Sci. 2018, 68, 358–366. [Google Scholar] [CrossRef]
  145. Gurav, R.G.; Jadhav, J.P. A novel source of biofertilizer from feather biomass for banana cultivation. Environ. Sci. Pollut. Res. 2013, 20, 4532–4539. [Google Scholar] [CrossRef] [PubMed]
  146. Melia, P.M.; Busquets, R.; Hooda, P.S.; Cundy, A.B.; Sohi, S.P. Driving forces and barriers in the removal of phosphorus from water using crop residue, wood and sewage sludge derived biochars. Sci. Total Environ. 2019, 675, 623–631. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  147. Pasquali, M.; Zanoletti, A.; Benassi, L.; Federici, S.; Depero, L.E.; Bontempi, E. Stabilized biomass ash as a sustainable substitute for commercial P-fertilizers. Land Degrad. Dev. 2018, 29, 2199–2207. [Google Scholar] [CrossRef]
  148. Wan, J.; Liu, X.; Wu, C.; Wu, Y. Nutrient capture and recycling by periphyton attached to modified agrowaste carriers. Environ. Sci. Pollut. Res. 2016, 23, 8035–8043. [Google Scholar] [CrossRef]
  149. Tabinda, A.B.; Fatima, U.; Batool, M.; Yasar, A.; Rasheed, R.; Iqbal, A.; Mahfooz, Y. A study on recycling and reuse of sugar mill industrial waste. Energy Sources Part A Recovery Util. Environ. Eff. 2021, 43, 1759–1768. [Google Scholar] [CrossRef]
  150. Liao, Y.; Chen, S.; Zheng, Q.; Huang, B.; Zhang, J.; Fu, H.; Gao, H. Removal and recovery of phosphorus from solution by bifunctional biochar. Inorg. Chem. Commun. 2022, 139, 109341. [Google Scholar] [CrossRef]
  151. Manca, A.; da Silva, M.R.; Guerrini, I.A.; Fernandes, D.M.; Villas Bôas, R.L.; da Silva, L.C.; da Fonseca, A.C.; Ruggiu, M.C.; Cruz, C.V.; Sivisaca, D.C.L.; et al. Composted sewage sludge with sugarcane bagasse as a commercial substrate for Eucalyptus urograndis seedling production. J. Clean. Prod. 2020, 269, 122145. [Google Scholar] [CrossRef]
  152. Yin, J.; Deng, C.B.; Wang, X.F.; Chen, G.; Mihucz, V.G.; Xu, P.G.; Deng, Q.C. Effects of Long-Term Application of Vinasse on Physicochemical Properties, Heavy Metals Content and Microbial Diversity in Sugarcane Field Soil. Sugar Technol. 2019, 21, 62–70. [Google Scholar] [CrossRef]
  153. Shilpi, S.; Lamb, D.; Bolan, N.; Seshadri, B.; Choppala, G.; Naidu, R. Waste to watt: Anaerobic digestion of wastewater irrigated biomass for energy and fertiliser production. J. Environ. Manag. 2019, 239, 73–83. [Google Scholar] [CrossRef]
  154. Guerrero, C.C.; de Brito, J.C.; Lapa, N.; Oliveira, J.F.S. Re-use of industrial orange wastes as organic fertilizers. Bioresour. Technol. 1995, 53, 43–51. [Google Scholar] [CrossRef]
  155. Ma, N.L.; Khoo, S.C.; Peng, W.; Ng, C.M.; the, C.H.; Park, Y.K.; Lam, S.S. Green application and toxic risk of used diaper and food waste as growth substitute for sustainable cultivation of oyster mushroom (Pleurotus ostreatus). J. Clean. Prod. 2020, 268, 122272. [Google Scholar] [CrossRef]
Table
Table 1. Major world producers and supply sources of phosphorus and phosphorite, both considered essential raw materials. Data from European Commission [17]. Percentages refer to major producers/importers only.
Table 1. Major world producers and supply sources of phosphorus and phosphorite, both considered essential raw materials. Data from European Commission [17]. Percentages refer to major producers/importers only.
Raw MaterialsMain World Producers (Average 2010–2014)Main EU Importers
(Average 2010–2014)		EU Source of Supply
(Average 2010–2014)		Import Reliance Rate *
PhosphoriteChina (44%)
Morocco (13%)
United States (13%)		Morocco (31%)
Russia (18%)
Syria (12%)
Algeria (12%)		Morocco (28%)
Russia (16%)
Finland (12%)
Syria (11%)
Algeria (10%)		88%
PhosphorusChina (58%)
Vietnam (19%)
Kazakhstan (13%)
United States (11%)		Kazakhstan (77%)
China (14%)
Vietnam (8%)		Kazakhstan (77%)
China (14%)
Vietnam (8%)		100%
(*) The “Import Reliance Rate” takes into account global supply and actual EU sourcing in the calculation of Supply Risk, and it is calculated as follows: EU net imports/(EU net imports + EU domestic production).
Table
Table 3. Technologies to remove phosphorus from water.
Table 3. Technologies to remove phosphorus from water.
TechnologiesFunctionProsConsConstrictionOperative Costs a EUR per 106 L of Treated WaterCost of 1 kg of P
Recovered a
Membrane filtrationSemi-permeable selective separation wallLow energy cost, low capital investment, high productivityMembrane foulingMembrane cleaning42–744-
Ion exchangeFunctionalised polymeric
matrices		Suitable for all ions, high productivityEconomic viabilityPre-treatment42–330-
PrecipitationSalt addedRemoval of suspended and dissolved solidsSodium carbonate management or H2S emissionsPlant maintenance32–3301.59
CrystallisationCa and/or Mg addedProduce granular hydroxyapatite or struvite--148–3050.64
Coagulation/flocculationAdding polymers or metal ions---32–330-
Thermochemical treatment of sewage sludgeMixes the ash with sodium-based saltsProduce P-enrich ash-Heavy metal-rich ash28–180 *-
Biological treatmentSelected bacteriaLow cost, high productivityAdditional treatment before P recoveryHigh concentrations of organic substrate32–330-
AdsorptionSurface phenomenon of molecular interactionLow cost, high productivityReduced ability to remove organic PSurface area and selectivity of adsorbent; contact time42–130-
a The costs expressed in different currencies were converted into EUR and discounted (http://rivaluta.istat.it:8080/Rivaluta/ accessed on 20 November 2022). * Expressed in EUR t−1 treated sludge.
Table
Table 4. Phosphorus removal with adsorption using adsorbents derived from agricultural wastes, metal industry wastes, and by advanced biological phosphorus removal with microorganisms. The table also shows the minimum concentration of the treated aqueous solution and the pH at which the highest removal efficiency has been achieved.
Table 4. Phosphorus removal with adsorption using adsorbents derived from agricultural wastes, metal industry wastes, and by advanced biological phosphorus removal with microorganisms. The table also shows the minimum concentration of the treated aqueous solution and the pH at which the highest removal efficiency has been achieved.
Material aP0 b mg L−1pHRecovery %Ref c
Bauxite residue17.795[83]
HPMM15.985[77]
Zr@MCS25.097[84]
Chrorella vulgaris37.093[85]
BS55.093[86]
Lanthanum-based hydrogel beads54.092[76]
RMA57.085[87]
Microalgae57.090[88]
PAO77.083[89]
ZSFB104.499[78]
Steel chips bed107.083[90]
CSH137.097[91]
Oil shale ash227.199[92]
ZrMCB402.094[79]
JP507.096[93]
CH507.083[93]
a Material: HPMM—high-permeability media mixture; RMA—red mud akaganeite; ZSFB—composite fibre composed of steel slag, zeolite, fly ash, basalt; BS—sugarcane bagasse; JP—jack fruit peel; CH—corn husk; Zr@MCS—Zr immobilised on modified corn straw; ZrMCB—corn bract-modified Zr; Microalgae—Dunaliella sp., Nannochloropsis sp., and Tetraselmis sp.; PAO—biofilm of phosphorus accumulating organisms; CSH—hydrated calcium silicate adsorbent; b P0—P initial concentration; c reference.
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Auteri, N.; Saiano, F.; Scalenghe, R. Recycling Phosphorus from Agricultural Streams: Grey and Green Solutions. Agronomy 2022, 12, 2938. https://doi.org/10.3390/agronomy12122938

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Auteri N, Saiano F, Scalenghe R. Recycling Phosphorus from Agricultural Streams: Grey and Green Solutions. Agronomy. 2022; 12(12):2938. https://doi.org/10.3390/agronomy12122938

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Auteri, Nicolò, Filippo Saiano, and Riccardo Scalenghe. 2022. "Recycling Phosphorus from Agricultural Streams: Grey and Green Solutions" Agronomy 12, no. 12: 2938. https://doi.org/10.3390/agronomy12122938

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