Efficient Phosphorus Recovery Research Articles

Efficient recovery of phosphorus and iron from the lithium extraction slag by the leaching precipitation method

ABSTRACT The key to recovering waste LiFePO4(LFP) is the recovery of lithium; however, the effective and synchronous recovery of phosphorus and iron resources still needs to be achieved. In this paper, a new process was proposed for recovering phosphorus and iron from the lithium extraction slag (LES) of waste LFP by the leaching and precipitation method. Based on the thermodynamic analysis of Fe3+ and PO4 3− and XRD results, the experimental conditions were discussed in detail. There were three stable regions when the solution pH value was from 0 to 5, no precipitation at pH = 0–0.664, stable existence of FePO4(s) at pH = 0.664–1.203, coexistence of FePO4(s), and AlPO4(s) when pH > 1.203, respectively. The leaching solution of LES by hydrochloric acid could prepare FePO4·2H2O under the following optimal conditions: 95°C, pH 1.5, feeding speed 1.5 mL min−1. The synthesised iron phosphate was pure and distributed in flakes. Additionally, the discharge capacity of the LiFePO4/C prepared by the regenerative FePO4·2H2O was 147 mAh g−1 at 0.1 C and showed good cycle stability at 1 C. The method not only recovers FePO4 from the LES but also shows simple operation and high efficiency.

Towards in-site carbon utilization and highly efficient nutrients removal: Effects of ammonium on the phosphorus recovery performance in a biofilm-based system

An alternatively anaerobic–aerobic biofilm system was operated for treating synthetic municipal wastewater for 150 days, and the effect of ammonium concentration in range of 15 mg∙L−1 - 50 mg∙L−1 on the phosphorus recovery performance was discussed. The ammonium concentration was confirmed as an important factor for balancing phosphorus accumulating organisms (PAOs) and denitrifying phosphorus-accumulating organisms (DPAOs) to affect nutrients removal and phosphorus recovery. The PAOs dominated in phosphorus removal with the ammonium less than 30 mg∙L−1, the ortho-P concentration in recovery steam was plateaued at 52 mg∙L−1. The increase in ammonium to 40 mg∙L−1 caused the seriously deterioration in PAOs activity; however, the phosphorus removal and recovery performance was decreased slightly which attributed to the vital contribution of DPAOs in phosphorus removal. The adverse effect of ammonium can be eliminated by decreasing the volume exchange ratio (VER) from 3.0 to 1.5, leading to the phosphorus concentration in recovery steam of 72.21 mg∙L−1. Meanwhile, the phosphorus removal efficiency (PRE) and total nitrogen removal efficiency (NRE) were stable at 97.8 % and 99.2 %, respectively, indicating highly efficient phosphorus recovery and nutrients removal in the biofilm system. The outcome of the present study could facilitate the establishment of an integrative technology to realize in-site carbon utilization, highly efficient nutrients removal and phosphorus recovery simultaneously in the mainstream treatment of sewage wastewater, and the study reveals the transformation pathways of P and N in the BPRR system, as well as the complex interactions between functional microorganisms.

Controllable fabrication of lanthanum-based metal-organic frameworks for efficient phosphorus recovery from water

In this study, lanthanum metal-organic frameworks (La-MOFs) with different microstructures were synthesized by changing the synthesis temperature (100, 130, 160, and 190 °C) and used for efficient phosphorus recovery from water. The results of adsorption isotherm measurements showed that the process of phosphorus recovery using the synthesized La-MOFs is more consistent with the Langmuir model. In addition, the kinetic behavior of this process is better described by the pseudo-second-order kinetic model. The synthesized La-MOFs can achieve efficient phosphorus recovery in water over an initial pH range of 3.0–11.0. The common ions found in water hardly affect the phosphorus recovery efficiency of the La-MOFs. Importantly, these materials have the potential to recover phosphorus from real water bodies. The synthesized La-MOFs exhibited excellent regeneration performance. The phosphorus recovery process is mainly governed by complexation between the La-MOFs and phosphorus species, as well as ligand exchange mechanisms. This study provides new technologies and methods for phosphorus recovery and reuse, including the treatment of water bodies that are threatened by eutrophication.

Efficient phosphorus recovery utilizing Magnesium-Modified Oil-Based drilling cutting Ash: Unraveling the role of ammonia nitrogen independent of struvite formation

A novel approach to phosphorus recovery is introduced in this study, employing alkali-melted and magnesium-modified oil-based drill cutting ash (AM-Mg-OBDCA) as highly efficient and cost-effective adsorbents. This innovation represents a notable stride in harnessing the resource potential of oil-based drill cutting ash (OBDCA). An investigation into the impact of ammonia nitrogen on phosphorus recovery was undertaken, revealing enhanced ammonia nitrogen removal in the presence of phosphorus. Simultaneously, the presence of ammonia nitrogen exhibited a favorable influence on phosphorus elimination across a broad pH range and in the co-presence of ions. Particularly under acidic conditions, AM-Mg-OBDCA demonstrated exceptional phosphorus adsorption efficiency. Conversely, co-existing carbonate ions were observed to significantly hinder phosphorus adsorption, while bicarbonate ions exerted only marginal inhibition on ammonia nitrogen adsorption. To discern the adsorption behavior, the pseudo-second-order and Langmuir models were applied, unveiling theoretical adsorption capacities of 161.8 mg/g and 98.81 mg/g for ammonia nitrogen and phosphorus onto AM-Mg-OBDCA, respectively. The forms of phosphorus in the spent AM-Mg-OBDCA were analyzed utilizing the Standard Measurement Test (SMT) phosphorus classification, shedding light on potential mechanisms governing phosphorus and ammonia nitrogen adsorption/co-adsorption. Investigation into the prospective reuse of AM-Mg-OBDCA as a fertilizer subsequent to phosphorus adsorption was conducted, bolstering its environmentally benign potential. In essence, this research introduces an inventive and efficacious strategy for repurposing OBDCA waste into functional materials with valuable applications. By tackling the challenges posed by phosphorus pollution and offering a pathway for resource utilization, this study makes a substantial contribution to the advancement of both environmental preservation and the development of sustainable materials.

Phosphorus recovery and resource utilization from phosphogypsum leachate via membrane-triggered adsorption and struvite crystallization approach

Phosphorus pollution from phosphogypsum (PG) leachate has caused severe problems in the water environment and ecology. Efficient phosphate recovery and resource utilization techniques are crucial as they can aid the phosphorus pollution problem and recover the scarcity of phosphorus resources. Herein, we developed a highly efficient phosphorus recovery strategy from PG leachate by integrating the ZrO2 membrane-triggered adsorption technique with the struvite crystallization process. More than 89.23% of the phosphorus anions in the PG leachate can be recovered via membrane-triggered adsorption. With the concentrated phosphate anions washed from membrane adsorption, the phosphate anions can be further employed for struvite crystallization, and an overall phosphorus recovery efficiency of 59.36% can be achieved. The obtained fine struvite product is of high purity, with NH4MgPO4·6H2O weight ratio of up to 89.83%. The novel strategy developed here demonstrates a green and sustainable strategy toward phosphorus recovery from the PG or PG-polluted groundwater or surface water leachate, which could be applied to practical phosphorus recovery and struvite fertilizer production. The commercialization of this strategy will shed light on the emergency PG pollution control at the YangtzeRiver upstream area.

Tri-functional lanthanum-based biochar for efficient phosphorus recovery, bacterial inhibition, and soil fertility enhancement

Excess phosphorus (P) in water can lead to eutrophication and upset ecological balance. In this study, biochar with ultrathin two-dimensional nanosheets from the natural mesocarp of shaddock was chosen as the carrier. The highly dispersed and small particle size of La(OH)3 on the surface of the nanosheets (MSBL3) was successfully achieved using chemical impregnation for the adsorption of P in aqueous solution, and the maximum adsorption capacity was 260.0 mg P g−1 [La]. The differences in surface crystallization of La(OH)3 on biochar at different La loadings were analyzed using the high-precision characterization methods. After six adsorption–desorption cycles, MSBL3 retained 76.7% of its initial performance in terms of the P adsorption capacity. The preparation of 1 g of MSBL3 costs about RMB 1, and it could reduce the P concentration in 2.6 ton of Laoyu River water to below the eutrophication threshold; and the inhibitory effect of MSBL3 on the eutrophication of water bodies was confirmed by the growth state of water hyacinth. Furthermore, 0.1 M MSBL3 could inhibit Escherichia coli and Staphylococcus aureus up to 98.7% and 85.0%, respectively, which indicates that MSBL3 can be used to recover P from water and also to improve water quality. In addition, the growth of the maize seedlings verified that the P-absorbed MSBL3 waste is a good soil fertilizer and can solve the problem of post-treatment of the adsorbent. In conclusion, MSBL3 prepared in this study is a promising P sorbent for application.Graphical

Release of phosphorus from thermal conversion of phosphorus-rich biomass chars – Evidence for carbothermic reduction of phosphates

Biomass can be used to generate heat, power, or biofuels in thermal conversion processes such as combustion, gasification and pyrolysis. However, some types of biomass contain high levels of phosphorus, which can be released to the gas phase and cause operational or environmental problems. The mechanism(s) responsible for phosphorus release has not been convincingly established. Understanding the high-temperature phosphorus chemistry is also important in order to enable efficient recovery of phosphorus in residues from thermal conversion of biomass. In this work, the release of phosphorus from wheat bran char and sunflower seed char in different gas environments (100 % N2, 1–20 % O2, and 10 % CO2) and temperatures (900–1100 °C) was studied. The chars were converted in a horizontal tube reactor and characterized using ICP-OES, XRD, SEM-EDS, and 31P NMR. The release of ash-forming elements was determined using ICP-OES analysis of the char and sample residues, whereas the release of carbon was determined using CO and CO2 gas analysis. In both chars, phosphorus was present primarily together with potassium and magnesium, mainly as pyrophosphates in the wheat bran char, and largely as orthophosphates in the sunflower seed char. For wheat bran char, the release of phosphorus increased from 27 % at 900 °C to 71 % at 1100 °C in N2, whereas the release was at least 20 % lower in the oxidizing atmospheres (1–20 % O2, or 10 % CO2). The sunflower seed char reached a maximum release of 55 % at 1100 °C in N2. For wheat bran char, the molar ratio of released carbon/phosphorus was close to 2.5, which fits well with the theoretical value for carbothermic reduction of phosphates (P2O5(s, l) + 5C(s) → P2(g) + 5CO(g)). At 1100 °C, in N2, the release of phosphorus, potassium and sodium occurred mainly during the first 10 min. It was shown that KMgPO4, used as a model compound, could be reduced by carbon starting from 950 °C, but that some of the phosphorus remained in the condensed phase. The work provides a better understanding of phosphorus release and presents evidence showing that carbothermic reduction reactions can be an important phosphorus release mechanism for seed- and grain-based biomass char.

Enabling efficient phosphorus recovery from cow manure: Liberation of phosphorus through acidification and recovery of phosphorus as calcium phosphate granules

Cow manure (CM) is one of the largest secondary sources of phosphorus, while mined phosphorus rock is becoming scarce and diminishing in quality. Phosphorus recovery from CM is essential for increasing the phosphorus use efficiency and, therefore, securing future food production. Calcium phosphate (CaP) granulation can enable efficient phosphorus recovery during anaerobic digestion. However, in CM, the absence of phosphorus in the ionic form and the high presence of inorganic carbon and magnesium inhibits CaP granulation. In this study, CaP granulation was achieved for the first time during CM treatment, using an up-flow anaerobic sludge blanket (UASB) reactor preceded by an acidifying continuously stirred tank reactor (CSTR). The UASB reactor and CSTR ran for 190 days at organic loading rates of 1 and 22.5 gCOD Lreactor-1 d-1, respectively. The acidification of CM at pH 5 dissolved struvite and calcium carbonate, causing > 94% of phosphorus, calcium and magnesium to be present as ions. In the UASB reactor fed with the CSTR effluent, 83 ± 3% of phosphorus was removed and mainly present as CaP granules > 2.5 mm in diameter. The CaP granules had a phosphorus content of 8.4 ± 1.3%P w/w with amorphous and crystalline calcium phosphate being the dominant phases. The formation of large and concentrated CaP granules causes accumulation at the bottom of the reactor and allows for simple size separation leading to efficient phosphorus recovery The recovery of CaP granules improves CM valorization and can reduce the transport of manure by up to 87%. The acidification prior to digestion thus promotes a more efficient use of phosphorus from CM in agriculture and can replace phosphorus from primary phosphorus sources.

A Novel Ca-Modified Biochar for Efficient Recovery of Phosphorus from Aqueous Solution and Its Application as a Phosphorus Biofertilizer.

Recovery phosphorus (P) from P-contaminated wastewater is an efficient and environmentally friendly mean to prevent water pollution and alleviate the P shortage crisis. In this study, oyster shell as calcium sources and peanut shells as carbon sources (mass ratio 1:1) were used to prepare a novel Ca-modified biochar (OBC) via co-pyrolysis, and its potential application after P adsorption as a P biofertilizer for soil was also investigated. The results shown that OBC had a remarkable P adsorption capacity from wastewater in a wide range of pH 4–12. The maximum P adsorption capacity of OBC was about 168.2 mg/g with adsorbent dosage 1 g/L, which was about 27.6 times that of the unmodified biochar. The adsorption isotherm and kinetic data were better described by Langmuir isotherm model (R2 > 0.986) and the pseudo second-order model (R2 > 0.975), respectively. Characterization analysis of OBC before and after P adsorption by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and specific surface area and porosity analyzer (BET) indicated that the remarkable P adsorption capacity of OBC was mainly ascribed to chemical precipitation, electrostatic adsorption, and hydrogen bonding. Pot experiment results showed that OBC after P adsorption could significantly promote the germination and growth of Spinacia, which manifested that OBC after P adsorption exhibited a good ability to be reused as P fertilizer for soil.

Preparation and characterization of MgO hybrid biochar and its mechanism for high efficient recovery of phosphorus from aqueous media

Conversion of organic waste into engineered metal-biochar composite is an effective way of enhancing biochar’s efficiency for adsorptive capture of phosphorus (P) from aqueous media. Thus, various strategies have been created for the production of metal-biochar composites; however, the complex preparation steps, high-cost metal salt reagent application, or extreme process equipment requirements involved in those strategies limited the large-scale production of metal-biochar composites. In this study, a novel biochar composite rich in magnesium oxides (MFBC) was directly produced through co-pyrolysis of magnesite with food waste; the product, MFBC was used to adsorptively capture P from solution and bio-liquid wastewater. The results showed that compared to the pristine food waste biochar, MFBC was a uniformly hybrid MgO biochar composite with a P capture capacity of 523.91 mg/g. The capture of P by MFBC was fitted using the Langmuir and pseudo-first-order kinetic models. The P adsorptive capture was controlled by MgHPO4 formation and electrostatic attraction, which was affected by the coexisting F− and CO32− ions. MFBC could recover more than 98% of P from the solution and bio-liquid wastewater. Although the P-adsorbed MFBC showed very limited reusability but it can be substituted for phosphate fertiliser in agricultural practices. This study provided an innovative technology for preparing MgO-biochar composite against P recovery from aqueous media, and also highlighted high-value-added approaches for resource utilization of bio-liquid wastewater and food waste.Graphical

Efficient phosphorus recovery as struvite by microbial electrolysis cell with stainless steel cathode: Struvite purity and experimental factors

Phosphorus (P) recovery from waste streams is an essential choice due to the coming global P crisis. One promising solution is to recover P by microbial electrolysis cell (MEC). Both the P recovery effectiveness and product quality are of critical importance for application. In this study, a two-chamber MEC was constructed and the effects of applied voltage, NaAc concentration, Mg/P molar ratio, N/P molar ratio, and initial P concentration on P recovery and product purity were explored. The maximum P recovery efficiency of 99.64 % and crystal accumulation rate over 106.49 g/m3-d were achieved. Struvite (MAP) was confirmed as the final recovered product and the purity obtained could reach up to 99.95 %. Besides, higher applied voltage, N/P molar ratio and initial P concentration could promote P recovery efficiency, while the purity of MAP showed correlation with applied voltage, Mg/P molar ratio, N/P molar ratio and initial P concentration. The correlation between NaAc concentration and both of the above was not very significant. A lower energy consumption of 4.1 kWh/kg P was observed at the maximum P recovery efficiency. In addition, the efficiency of P recovery from real wastewater also could reach nearly 88.25 %. These results highlight the promising potential of efficient phosphorus recovery from P-rich wastewater by MEC.

Struvite crystallization by using active serpentine: An innovative application for the economical and efficient recovery of phosphorus from black water

Recovery of phosphorus from wastewater through struvite crystallization is one of the most attractive methods. However, the cost of chemical consumption makes this technology is unattractive to some extent. In this work, highly active serpentine was prepared by one-step mechanical activation and then used to recover phosphate as struvite from the black water containing 132.8 mg/L phosphorus and 3144 mg/L ammonia nitrogen. The results indicated that the prepared active serpentine can release magnesium ions and hydroxide ions simultaneously into an aqueous solution and is an ideal raw material for struvite crystallization. The factors for phosphorus recovery in this process mainly include mechanical activation intensity, serpentine dosage, and contact time. For the actual black water, a high recovery rate of phosphorus (>98%) is achieved by using active serpentine as the magnesium and alkali source for struvite precipitation. The recovery product was identified as struvite with a median particle size of 32.96 μm. It was confirmed that the mechanical activation damaged the crystal structure of the raw serpentine, improving the activity of Mg2+ and OH−. The undissolved Si-containing particles act as crystal seeds, accelerating the struvite crystallization process. Furthermore, a pilot-scale test was conducted with a rural public toilet in Xiong'an New District, Hebei Province. The results showed that an acceptable phosphorus recovery (98%) could be achieved using active serpentine. Additionally, it was demonstrated that the serpentine process to recover phosphate as struvite reduced the cost by 54.4% in compared with an ordinary chemical process. The active serpentine is a promising dual source of magnesium and alkali for the phosphorus recovery by the struvite method. It has a potential prospect for the large-scale application in phosphorus recovery and struvite fertilizer production.

Highly efficient phosphorus recovery from sludge and manure biochars using potassium acetate pre-treatment

Pyrolysis converts nutrient-rich residues (e.g., sewage sludge and manures) into biochar with low levels of organic contaminants and high nutrient contents. However, the availability of phosphorus (P) as one of the key nutrients in such biochar tends to be low and new approaches are needed to enhance P-availability. In this work we tested and optimised one such method, doping biomass prior to pyrolysis with potassium (K) as potassium acetate. The treatment worked effectively in both pyrolysis units tested (microscale and lab-scale, continuous unit) and all three feedstocks (two types of sewage sludges and swine manure). The most dramatic effect was observed in the microscale pyrolysis unit at 400 °C where 5% K doping increased the water-extractable P content 700-fold to 43% of total P. Of the added K, on average 90% was retained in biochar after pyrolysis of which ∼50% was water-extractable. The proposed method enables conversion of low-value residues into valuable resources with agronomically relevant total and available P and K levels. This approach does not require specialised equipment or process modifications and is therefore easy to implement and relatively cheap (∼US$ 60–80 t−1 treated feedstock). It can present an urgently required solution to fulfil regulatory requirements for P-recovery.

Phosphorus recovery from pig manure: Dissolution of struvite and formation of calcium phosphate granules during anaerobic digestion with calcium addition

Phosphorus is an essential but finite and scarce element, which is used extensively in pig farming. For recovering phosphorus from pig manure, we hypothesize that calcium addition during anaerobic treatment can trigger calcium phosphate granulation and enable efficient phosphorus recovery. In this study, we tested the recovery of phosphorus from pig manure by adding calcium during anaerobic treatment. Size–separated (<200 µm) pig manure was treated in two identical up-flow anaerobic sludge blanket reactors for 456 days. Calcium was supplied to one of the reactors to study calcium phosphate granulation.Calcium addition showed a positive effect on treatment stability and efficiency, increasing chemical oxygen demand and phosphorus removal. Phosphorus removal increased from 60% without calcium addition to 74% with calcium addition. The addition of calcium increased the phosphorus concentration in significantly larger particles, calcium phosphate granules, (79% >0.4 mm compared with 11% without calcium addition) in the reactor with calcium addition, which enables separation and a transport reduction of 85% for the recovered phosphorus. The main phosphorus phase in the reactor sludge bed changed from struvite to calcium phosphate with calcium addition. The Mg:P molar ratio was 0.09 with calcium addition and 0.88 without calcium addition in particles >2.5 mm. Thus, calcium addition enhances the treatment of pig manure and enables phosphate recovery as calcium phosphate granules.

Efficient Phosphorus Recovery from Municipal Wastewater Using Enhanced Biological Phosphorus Removal in an Anaerobic/Anoxic/Aerobic Membrane Bioreactor and Magnesium-Based Pellets.

Municipal wastewater has been identified as a potential source of natural phosphorus (P) that is projected to become depleted in a few decades based on current exploitation rates. This paper focuses on combining a bench-scale anaerobic/anoxic/aerobic membrane bioreactor (MBR) and magnesium carbonate (MgCO3)-based pellets to effectively recover P from municipal wastewater. Ethanol was introduced into the anoxic zone of the MBR system as an external carbon source to improve P release via the enhanced biological phosphorus removal (EBPR) mechanism, making it available for adsorption by the continuous-flow MgCO3 pellet column. An increase in the concentration of P in the MBR effluent led to an increase in the P adsorption capacity of the MgCO3 pellets. As a result, the anaerobic/anoxic/aerobic MBR system, combined with a MgCO3 pellet column and ethanol, achieved 91.6% P recovery from municipal wastewater, resulting in a maximum P adsorption capacity of 12.8 mg P/g MgCO3 through the continuous-flow MgCO3 pellet column. Although the introduction of ethanol into the anoxic zone was instrumental in releasing P through the EBPR, it could potentially increase membrane fouling by increasing the concentration of extracellular polymeric substances (EPSs) in the anoxic zone.

Production of Calcium-Rich Biochar from Poplar Leaves for Efficient Phosphorus Recovery from Water

Production of Calcium-Rich Biochar from Poplar Leaves for Efficient Phosphorus Recovery from Water

Efficient phosphorus recovery by enhanced hydroxyapatite formation in a high loading anammox expanded bed reactor at 15 °C

Wastewater such as digestate from waste biomass anaerobic digestion contains a high concentration of nutrients such as nitrogen and phosphorus. A novel process for simultaneous nitrogen removal and phosphorus recovery was recently developed based on the combination of the anammox process and hydroxyapatite (HAP) crystallization. This study firstly investigated the feasibility of operating this process under low temperature using an anammox-HAP type expanded bed reactor. By gradually increasing nitrogen loading and phosphorus loading rate, a nitrogen removal rate of 8.45 ± 0.49 gN/L/d with a simultaneous phosphorus recovery rate of 0.63 ± 0.06 gP/L/d was obtained at 15 °C. The efficiency for both nitrogen removal and phosphorus recovery was higher than 80%. The addition of Ca2+ was confirmed to be an effective strategy to enhance the efficiency of phosphorus recovery by affecting the supersaturation condition of the solution. However, a high phosphorus load may result in excessively high mineral concentrations in the sludge and affect anammox performance. The granular sludge formed under low temperature conditions in this study has a typical double-layer structure of HAP-core and anammox biofilm. This study firstly demonstrated the feasibility of the anammox-HAP process even under low temperatures and give new options for future digestate treatment.

Efficient recovery of phosphorus and sulfur from Anaerobic Membrane Bioreactor (AnMBR) permeate using chemical addition of iron and evaluation of its nutrient availability for plant uptake

Anaerobic membrane bioreactors (AnMBRs) represent an emerging environmental biotechnology platform with the potential to simultaneously recover water, energy, and nutrients from concentrated wastewaters. The removal and beneficial capture of nutrients from AnMBR permeate has yet to be fully explored, therefore this study sought to foster iron phosphate recovery through a tertiary coagulation process, as well as characterize the recovered nutrient product (RNP) and assess its net phosphorus release, diffusion, and availability for plant uptake. One of the primary goals of this study was to optimize the dose of the coagulant, ferric chloride, and coagulant aid, aluminum chlorohydrate (ACH), for continuous application to the coagulation-flocculation-sedimentation (CFS) unit of an AnMBR pilot plant treating municipal wastewater, through controlled bench-scale jar tests. Anaerobic systems present unique challenges for nutrient capture, including high, dissolved hydrogen sulfide concentrations, along with settleability issues. The addition of the coagulant aid increases settleability, while enhancing phosphorus removal by up to 20%, decreasing iron demand. Water quality analysis indicated that a variety of factors affect nutrient capture, including the COD (chemical oxygen demand) concentration of the permeate and the limiting coagulant dose. COD >200 mg/L was shown to decrease the phosphorus removal efficiency by up to 15%. A combination of inductively coupled plasma optical emission spectrometer (ICP-OES) elemental analysis, inductively coupled plasma mass spectrometer (ICP-MS) elemental analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray absorption near-edge structure (XANES) spectroscopy analysis was used to characterize the P-rich RNP which revealed a 2.58% w/w phosphorus content and the lack of a well-defined crystalline structure. Detailed studies on resin extractable phosphorus to assess the plant uptake potential also demonstrated that iron-based P-rich RNPs may not be an effective fertilizer product, as they can act as a phosphorus sink in some agricultural systems instead of a source.

Toward a decision support framework for sustainable phosphorus management: A case study of China

Phosphorus is an essential nutrient for plant growth, as well as a critical element involved with biological metabolism. Current phosphorus utilization efficiencies in most counties are below 20%, which results in significant phosphorus loss and brings severe environmental challenges. Therefore, phosphorus flow management and recovery technologies are of great importance for global sustainable development. However, there is little research available to link up phosphorus flow management and recovery technology development. This paper proposed a systematic, hierarchical framework based on fuzzy comprehensive evaluation (FCE) to identify cost-effective waste streams and suitable technologies for efficient phosphorus recovery, while China is used as a case study to demonstrate its effectiveness. Within this framework, substance flow analysis (SFA) is used to track phosphorus flows in China, and different indicators covering phosphorus quantity, process economics, product safety and their environmental impacts were considered. By using FCE, these indicators were combined into a single score for decision making. Principal component analysis (PCA) was further incorporated to identify barriers and directions for future research and development. Although the data collection was still a challenge, the preliminary insights demonstrated that phosphorus recovery from livestock urine in China is the most cost-effective solution. The framework not only supports decision-makers to formulate national and international phosphorus policies and thus improve global sustainability, but also could be applied to other resources management such as nitrogen and rare earth elements in the future.

Analysis and balance of phosphorous removal from wastewater at urban wastewater treatment plant

Abstract:Phosphorus is a major substance that is needed especially for agricultural production or for the industry. At the same time it is an important component of wastewater. At present, the waste management priority is recycling and this requirement is also transferred to wastewater treatment plants. Substances in wastewater can be recovered and utilized. In Europe (in Germany and Austria already legally binding), access to phosphorus-containing sewage treatment is changing. This paper dealt with the issue of phosphorus on the sewage treatment plant in Nitra. There are several industrial areas in Nitra where record major producers in phosphorus production in sewage. The new wastewater treatment plant is built as a mechanicalbiological wastewater treatment plant with simultaneous nitrification and denitrification, sludge regeneration, an anaerobic zone for biological phosphorus removal at the beginning of the process and chemical phosphorus precipitation. The sludge management is anaerobic sludge stabilization with heating and mechanical dewatering of stabilized sludge and gas management. The aim of the work was to document the phosphorus balance in all parts of the wastewater treatment plant - from the inflow of raw water to the outflow of purified water and the production of excess sludge. Balancing quantities in the wastewater treatment plant treatment processes provide information where efficient phosphorus recovery could be possible. The mean daily value of P tot is approximately 122.3 kg/day of these two sources. The mean daily value of P tot is approximately 122.3 kg/day of these two sources. There are also two outflows - drainage of cleaned water to the recipient - the river Nitra - 9.9 kg Ptot/day and Ptot content in sewage sludge - about 120.3 kg Ptot/day - total 130.2 kg Ptot/day.