Phosphorus speciation in drinking water treatment residuals


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Phosphorus speciation in drinking water treatment residuals

  1. 1. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 1, No.1, 2011 Phosphorus Speciation in Drinking Water Treatment Residuals (WTRs) and Biosolids-Amended Soils Using XANES Spectroscopy Mahdy Ahmed Department of Soil and Water, College of Agriculture, Alexandria University, Alexandria Elshatby,21545, Alexandria University, Alexandria, Egypt Tel: 003-02-5904684 E-mail: Elkhatib Elsayed Department of Soil and Water, College of Agriculture, Alexandria University, Alexandria Elshatby,21545, Alexandria University, Alexandria, Egypt Tel: 003-02-5904684 E-mail: Fathi Nieven Salinity and Alkalinity Soils Research Laboratory Ministry of Agriculture, Cairo, Egypt Tel: 003-02-5046479 E-mail: Lin Zhi-Qing Environmental Sciences Program & Department of Biological Sciences Southern Illinois University, Edwardsville, Illinois 62026, USA E-mail: zhlin@siue.eduAbstractX-ray absorption near-edge structure (XANES) spectroscopy (a non-destructive chemical-speciationtechnique) is a useful technique available for determining the speciation of P in various environmentalsamplesTwo incubation studies were conducted to assess the P species formed in an originally neutraland alkaline soil in response to high biosolids and/or WTRs applications using P K-edge X-rayabsorption near edge structure (XANES) spectroscopy. The results indicated that combination of Pstandards yielding the best linear combination fits for biosolids were phytic acid (26.03%) andCu3(PO4)2 (73.09%) and a little of P-sorbed to Al hydroxide (0.89%). However, The combination of Pstandards yielding the best linear combination fits for WTRs were P-sorbed to Fe hydroxide (64.19%),phytic acid (30.72%) and P-sorbed to Al hydroxide (5.07%). The P speciation in 10 g kg-1-treated claysoils were phytic acid (19.08%), Mn3 (PO4)2 (0.79%), Phytic acid(K,Mg salt)(11.22%), Cu3(PO4)2(7.26%), and hydroxyapatite (57.98%). Addition of WTRs modified the P speciation in biosolids-amended soils, and the changes varied depending on biosolids and WTRs application rates. The Pspeciation in soils depends on the soil type and application rates of biosolids and WTRs.Keywords: Biosolids, P, XANES, WTRs, Soils1. IntroductionLand application of biosolids on agricultural fields generally serves two main purposes: first, itprovides essential nutrients to crops; and second, it serves as a means of waste disposal for wastewatertreatments plants. Biosolids supplies phosphorus (P) to the soil (Kingery et al. 1993; Evers 1998), andcontributes to increased yields of forage and field crops where P was previously limiting production(Brink et al 2002; Cooperband et al. 2002; Balkcom et al. 2003). However, when land application isaimed primarily at supplying nitrogen (N) to crops and/or reducing the waste volume, P applied withbiosolids can far exceed the amount of P required by most crops (Eghball et al. 1999). For example, atypical N:P uptake ratio for corn is 7.5:1 (U.S. EPA 1981), while the N:P ratio for biosolids reported in6|
  2. 2. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 1, No.1, 2011the literature tends to be approximately 2.5:1 (Edwards & Daniel 1992). Initially soils will retain mostof the P applied in excess of crop uptake through various transformation processes includingimmobilization, adsorption, and precipitation. Apart from plant uptake, P can be lost by surface erosion(Pionke et al. 2000; Smith et al. 2001) and/or subsequently by leaching (McDowell et al. 2004). Suchlosses have resulted in eutrophication of rivers and lakes in the past decades (Daniel et al. 1998;Sharpley et al. 2001). Adsorptions to surfaces of iron (Fe) and aluminum (Al) oxides and clay mineralsand precipitation as secondary Fe and Al P minerals are predominant reactions for solution P in acidicsoils and as Ca P minerals in alkaline soils. Alum [Al2(SO4)3⋅18H2O] is commonly used at municipaldrinking water treatment plants for water purification. It is added at the head of the water treatmentprocess to remove fine particulates and, therefore, reduce water turbidity. Alum serves as a coagulantand forms particulate complexes that are then settled out and removed along with lime sludge, termedas water treatment residues (WTRs). These WTRs commonly contain high levels of aluminum (Al),calcium (Ca), iron (Fe) and other major cations that have potential for reacting with P to form water-insoluble phosphate compounds and reduce the bioavailability of P in agricultural soils (Basta et al.2000). For example, O’Connor & Elliott (2002) indicated that the addition of WTRs had dramaticallyreduced soluble P in soil leachates. Staats et al. (2004) further reported that the use of alum as a poultrylitter amendment effectively reduced soluble P in the poultry litter. As a result, one may suggest that theco-application of WTRs and biosolids promote agricultural land use of biosolids (Elliot et al. 2002).There is, however, a limited amount of information on potential chemical interaction between P inbiosolids and major cations in WTRs, particularly regarding P speciation and temporal dynamics in themixture of biosolids and WTRs. Furthermore, chemical processes for the co-precipitation andchemical-physical processes for adsorption of P with amorphous Al- and Fe-hydrous oxides or otherminerals, which are major components in biosolids and/or WTRS, needs to be elucidated. P speciationin soils amended with biosolids and drinking water treatment residuals(WTRs) is essential in providinginformation to formulate best management practices(BMPs) to mitigate surface water degradationthrough eutrophication ( Beauchemin et al. 2003; Shober et al. 2006; Ajiboye & Akinremi 2007).Different P species have very different physiochemical properties, which can determine their relativetendency to precipitate, adsorb, or dissolve in soil solution. Shober et a. (2006) conducted P speciationanalysis on biosolids that had been treated with Al2(SO4)3 or FeCl3 compounds that are commonly usedin drinking water treatment. Their study showed a reduced solubility of P in biosolids that were treatedwith the chemicals. Other P-speciation studies using biosolids and animal manures have elucidatedconsistent results regarding chemical forms of P (Beauchemin et al. 2003; Ajiboye et al. 2007). Theseprevious studies determined that the dominant P species were calcium phosphate species such ashydroxyapatite (calcium phosphate or HAP) and amorphous Al- and Fe- P species (Beauchemin et al.2003; Shober et al. 2006; Ajiboye et al. 2007). All of the P species are precipitated minerals (or notsurface adsorbed) and thus are not subject to a Pmax adsorption value. It was observed by Beaucheminet al. (2003) that HAP was the most dominant species at all pH levels observed, but especiallydominant at lower pH values. Because of the thermodynamic stability of HAP, it can be a major sinkfor P in a non labile state. When compared to manures, HAP is more dominant in biosolids and thewater soluble P concentration was higher in extractions of manures than biosolids (Ajiboye et al. 2007).It has been suggested that the lower P lability and higher HAP dominance in biosolids result from thelime stabilization often used for treatment before land application (Ajiboye et al. 2007).X-ray absorption near-edge structure (XANES) spectroscopy (a non-destructive chemical-speciationtechnique) is a useful technique available for determining the speciation of P in various environmentalsamples (Khare et al. 2005; Sato et al. 2005; Pickering et al. 1995). Because of the non-destructivenature of this technique, XANES analysis directly identifies the chemical species present withoutsignificant chemical modification. Each chemical species has a characteristic emission spectrum.Known standards are analyzed and then a curve fitting technique is applied to determine P speciespresent in unknown samples. The objective of this study was: to assess the P species formed in anoriginally neutral and alkaline soil in response to high biosolids and/or WTRs applications using P K-edge x-ray absorption near edge structure (XANES) spectroscopy.2. Materials and Methods2.1 Sample Collection and PreparationThree Egyptian soil types were selected for this study: Kafr El-Dawar soil (Typic torrifluvent, from7|
  3. 3. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 1, No.1, 2011Elbohera Governorate, Egypt), El-Bostan soil (Typic torripsamment, from Elbohera Governorate,Egypt), and Borg Al-Arab soil (Typic calciorthids, from Alexandria Governorate, Egypt). Soils werecollected from a depth of 0-15 cm at each sampling location. Air-dried soil samples were ground andsubsequently sieved (< 2 mm). The experimental dried biosolids were obtained from the GeneralOrganization Sanitory (GOS) in Alexandria City (Station No 9), Egypt. The WTRs were collected fromthe drinking water treatment plant in Kafr El-Dawar, Elbohera Governorate, Egypt. Both biosolids andWTRs were air-dried and sieved (< 2 mm) prior to use (Makris & Harris 2005).The general physio-chemical properties of the soils, biosolids, and WTRs are compiled in Table (1). Soil pH and electricalconductivity (EC) were determined using the paste extract method (Richards 1954); WTR and biosolidpH and EC were analyzed using 1:2.5 suspension (Richards 1954); Calcium carbonate content wasdetermined by calcimeter (Nelson 1982); Particle size distribution was measured according to thehydrometer method (Day 1965); The organic matter content (OM) of the samples was determined bydichromate oxidation method (Nelson & Sommers 1982); Cation exchange capacity (CEC) wasdetermined using 1 M NaOAC (Rhoades 1982). In addition, KCl-extractable Al was determinedcolorimetrically using 8-hydroxy quinoline butyl acetate method (Bloom et al. 1978). The availablephosphorus was determined according to Olsen & Sommers (1982). The DTPA extractable heavymetals was determined according to Lindsay & Norvell,(1978). Concentrations of total metals weredetermined using ICP-MS according to Ure (1995). Field capacity (FC) was determined by thepressure-plate method (Tan 1996).The American soil was collected from an agricultural field in Liberty, Illinois located at 685872E,44201764N zone 15s. The soil had not been amended with biosolids or animal manures for at least 25years. Soils were analyzed for general properties according to Page et al. (1982) (Table 2).Biosolids were collected from the Troy Municipal Wastewater Treatment Plant in Troy, Illinois inFebruary, 2005. The plant treats domestic sewage sludge for a community of approximately 10,000residents with no input from major industry. The water content of the biosolids was 75%. The pH of thebiosolids was 11.9±0.2. Biosolids were stored indoors in plastic buckets.Drinking water treatment residuals (WTRs) were collected from the Hartford Drinking WaterTreatment Facility in Hartford, Illinois in September, 2005. The facility has been in operation since1971 serving a community of approximately 1,500 residents. The WTRs were turbulently released fromthe water treatment process as liquid containing suspended solid particulates at a concentration of a fewpercent. The WTRs were taken directly from holding tanks, where coagulated particulates and alumand lime treatment are allowed to precipitate from water. Once WTRs were in buckets and tubs theyrapidly precipitated so the water could be decanted off. Water was removed at collection and for theweeks following collection until the WTRs reached a moisture content of 100%. The pH of the WTRswas 9.0±0. WTRs were stored indoors in plastic buckets. Moisture content for all experiments wasdetermined by weighing moist samples then oven drying and weighing dry samples.Soils, biosolids, and WTRs were chemically characterized using inductively coupled plasma massspectroscopy (ICP-MS) to determine concentrations of different elements (Table 2). Samples wereoven-dried at 45ºC for 3 days and ground to a fine powder in an agate mortar and pestle. Groundsamples were digested using EPA method 3050B for sludges and soils.2.2 Soils Incubation ExperimentsIn the Egyptian experiment, different application rates of WTRs (0, 1, 2, 3, and 4%, w/w, DW) andbiosolids (0, 1, 2 and 3%, w/w) were added to each soil by fixing one rate of biosolids and varying therate of WTRs. The experimental soil was thoroughly mixed with the biosolids and WTRs and then thetreated soil was transferred to a large plastic bin. The soils that were not treated with the biosolids andWTRs were used as the control. Distilled water was added to obtain the desired soil field capacity (FC).The treated soils were then transferred to polypropylene jars, and brought to the field capacity. The soilmoisture content in the treated soil was kept constantly at the field capacity level during the incubationperiod by periodically weighing the jars and adding distilled water to compensate for the water lossthrough evaporation. The jars were covered with perforated plastic film and incubated at 25 °C for 60days. The experimental design was a split-split plot design, with four replicates of each treatment (240jars). After the incubation period, soil samples were air-dried, crushed to pass a 2-mm sieve, and storedtill chemical analysis.8|
  4. 4. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 1, No.1, 2011In the American experiment, all samples of soil, biosolid and WTR were ground to a fine powder usinga ceramic mortar and pestle. After grinding, each of the three components (biosolids, WTRs, and soil)was weighed appropriately to provide each of the following treatments: WTR rates (0, 20, 40, 80, and160 g WTRs kg-1 soil). Each WTR treatment level was crossed with biosolid loading rates of (0, 25,and 50g biosolid kg-1 soil). The experimental design used was a completely randomized designrepeated for each level of biosolids application. This design was chosen because the purpose of theobjective of the experiment was to determine the effects of WTRs. The mixtures were scaled to providea total of 50g of soil, biosolid, and WTRs combined. Sample mixtures were placed into plastic cupsand saturated with distilled water. The samples were placed randomly on a bench at room temperaturefor a period of 30 days. After ten days of incubation all samples were re-saturated then re-saturatedagain at 20 days. At 30 days the samples were removed from the plastic cups and laid on drying paperto air dry for 3 days. After air drying was complete, all samples were ground in a ceramic mortar andpestle then placed into plastic bags.2.3 X-ray absorption near-edge structure (XANES) analysisThe XANES analysis was carried out at the Synchrotron Radiation Centre (SRC) at Stoughton,Wisconsin. The biosolids and sample mixtures of biosolids and WTRs were attached in a thin layerover double-sided conducting carbon tape, and the sample target was positioned at a 45-degree angle tothe X-ray beam. X-ray absorption spectra (near edge structure) were collected by monitoring the P K-edge fluorescence using the double crystal monochromator (DCM) beam-line of the CanadianSynchrotron Radiation Facility, having a 13-element Ge detector and cryostat for spectrum collection ina series of replicate scans. The source electron energy ranged from 800 to 1000 MeV, with a currentranging from approximately 120 to 250 mA. Additional information regarding the P calibration hasbeen reported in details previously by Lombi et al. (2006) and Ajiboye et al. (2007). The analysis of theXANES spectra was performed using an edge-fitting method using SIXPack software as described byWebb (2005). The normalized edge spectrum of a sample containing unknown P species was fitted to aliner combination of the spectra of standard P compounds by using a least-squares minimizationprocedure.2.4 Phosphorus standards for XANES spectroscopyBased on the principle components analysis (PCA) identification (Seiter et al. 2008), the following 14 Pstandards were selected to fit potential P species present in the biosolids and WTRs samples: AlPO4crystal, wet, amorphous AlPO4, P-sorbed on amorphous Al2(OH)3 , Ca3(PO4)3, Na3PO4.12H2O,(NH4)MgPO4·xH2O, Phytic acid (corn) (H12IP6), CaH10P6 , Ca6IP6 , Na12IP6 , Phytic acid dodecasodium(C6H17NaO24P6) , K4Mg2H4IP6 , K2H10IP6 , and Hydroxyapatite. SixPACK software (Webb 2005) wasused to average replicate spectra from each sample and fit the averaged spectra to those of standards.The software calculated the percentage of each P standard in the sample using a least squares fit. ThePCA analysis eliminated insignificant P species leaving only those contributing a major component inthe sample.3. Results and Discussion3.1 Phosphorus Forms inBbiosolids and WTRsThe heterogeneity of the biosolids and WTRs samples provided a challenge for the interpretation of theP-XANES spectra. However, several distinctive features could be identified on the spectra (Figure 1).The combination of P standards yielding the best linear combination fits for biosolids were Ba6 withphytic acid (26.03%) and Cu3 (PO4)2(73.09%) and a little of P-sorbed to Al hydroxide(0.89%).However, The combination of P standards yielding the best linear combination fits for WTRswere P-sorbed to Fe hydroxide (64.19%), phytic acid (30.72%) and P-sorbed to Al hydroxide (5.07%).This is largely in consistent with the results reported by Shober et al (2006) and Daniel (2010).3.2 Phosphorus Forms in Biosolids-Treated Soils9|
  5. 5. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 1, No.1, 2011The relative proportion of phosphate that best fit biosolids, WTRs, and selected WTRs-Biosolids-treated soils XANES spectra in linear combination fitting are shown in Table (3).The combination of P standards yielding the best linear combination fits for 10 g kg-1-treated Kafr El-Dawar soils were phytic acid (Na salt)(19.08%), Mn3 (PO4)2(0.79%), KMgH9IP6(11.22%),Cu3(PO4)2(7.26%),phytic acid(3.67%), and Hydroxyapatite(57.98%)(Table 3). Also, the best linearcombination fits for 10 g kg-1-treated El-Bostan soils were amorphous Fe-phosphate (47.02%),KH2PO4(10.93%), Hydroxyapatite(17.21%), P-sorbed to Al hydroxide(16.13%), and Al FePO4(8.70%).However, the P-XANES spectra of 10 g kg-1-treated Borg Al-Arab soils were31.16%±0.02 Zn3 (PO4)2, 12.63%±0.01Al PO4, 3.10% ± 0.02 Cu3(PO4)2, 13.16%±0.02 Hydroxyapatite,11.37%±0.02 Fe hydroxide with P-sorbed, 15.58% ± 0.03 CaH10P6, and 12.90%±0.03 H12 IP6(phyticacid). In contrast, the increasing of biosolids application rates to 30 g kg-1 changed the percentage ofcompounds presented in biosolids-treated soils (Table 3). The P-XANES spectra of 30 g kg-1-treatedKafr El-Dawar soils were 15.34% ± 0.02 amorphous Al-phosphate, 29.53% ± 0.01 Al PO4, 39.67% ±0.02 CaH10P6, and15.46%±0.02 H12 IP6 .While, in El-Bostan soils treated with 30 g kg-1 biosolidsapplication rate, the best linear combination fits were 14.84%±0.005 Al PO4, 19.51%±0.03 CaH10P6,and65.64% ± 0.02 H12 IP6(phytic acid). Also, the forms in Borg Al-Arab soils were 32.27%±0.02amorphous Al-phosphate, 21.39% ± 0.01 Al PO4, 17.61% ± 0.01 Hydroxyapatite, 21.01%±0.02Ammonium magnesium phosphate, 1.62% ± 0.01 K4Mg2H4IP6 , and 6.07% ± 0.01 Al Fe PO4. Similarly,the P-speciation of USA biosolids used in this study was similar. The combination of P standardsyielding the best linear combination fits for USA 50 g kg-1biosolids-treated soil were 13.50% ± 0.06 KMg Hg IP6, 47.50% ± 0.02 Fe hydroxide with P-sorbed, and 38.80% ± 0.04 H12IP6(Table 3). Spectrumof the other treatments was discarded from the result because of its strong spectral noise andunreliability. These results coincide with the results of Shober et al (2006) and Daniel (2010),butdifferent results were found in the study of Sato et al.(2005). This may suggest that certain forms of Pwere present in the biosolids-treated soil that was not adequately represented by the standards used forfitting. A greater variety of P standards may need to be considered in future work.3.3 Phosphorus Forms in WTRs-Biosolids-Treated SoilsAddition of WTRs modified the P speciation in biosolids-amended soils, and the changes varieddepending on the specific P speciation and biosolids and WTRs application rates (Figs.2 and 3,Table 3).In 10 biosolids-amended Kafr El-Dawar soil, addition of 10 WTRs significantly changedthe P speciation and the best linear combination fits were 83.82% ± 0.01 Al hydroxide with P-sorbedand 16.19% ± 0.01 Al Fe PO4 ,so proportion of phosphate sorbed to Al hydroxide increased after WTRsapplication. However, for El-Bostan soil, the P speciation were 45.36%±0.02 Al PO4, 51.17%±0.01 H12IP6, and 3.45%±0.02 Al Fe PO4.While, the P speciation in Borg Al-Arab soil were 5.39%±0.01 Al FePO4, 45.36%±0.02 Al PO4, 51.17%±0.01 H12 IP6, and 3.45%±0.02 Al Fe PO4. While one may assumethat portion of total P in biosolids that was fitted as Al-hydroxide-bound P can actually be the sum ofweakly sorbed P and soluble hydrated salts (e.g., K or Na phosphate), as differences in the XANESspectral features of aqueous P standards and PO4 sorbed to Al hydroxides were subtle (Peak et al.,2002), it is also possible that PO4 sorbed to Al hydroxide becomes more and more in-reversible withthe progress of P absorption that occurs by penetrating from outer layer to the inner layer of the subjectgranular. Thus, potentials for loss of P to water resource can be reduced. Increasing application rate ofWTRs to 40 did not change P speciation in Kafr El-Dawar and El-Bostan soils(Table 3), but theproportion of forms was changed. On the contrary, P speciation in Borg Al-Arab soil were changed andthe best linear combination fits were 23.62%±0.05 Al PO4, 46.37%±0.02 Hydroxyapatite, 26.81%±0.0H12 IP6, and 3.18%±0.04 Fe hydroxide with P-sorbed.The Hydroxyapatite form was predominant inBorg Al-Arab soil because it has a high content of calcium carbonate. Mechanisms of appearance ofCaP compounds in the soil upon manure application include (i) formation of secondary CaP minerals;(ii) phosphate adsorption to the surface of CaCO3 (Peak et al., 2002); and/or (iii) surface precipitates ofphosphate with adsorbed calcium on Fe-oxide surface. In soils amended with high rate of biosolids(, application of 10 WTRs significantly changed the P speciation and proportion of formsfound.For example, the P speciation in Kafr El-Dawar soil were 14.27%±0.02 Ca3 (PO4)2,71.49%±0.02 Hydroxyapatite, and 14.23%±0.004 Al Fe PO4.while, the best linear combination fitswere 18.86%±0.05 Ca3 (PO4)2, 47.23%±0.04 Hydroxyapatite, 5.35%±0.03 CaH10P6, and 28.55%±0.02H12 IP6 in El-Bostan soils(Table 3). However, the forms in Borg Al-Arab soil were 24.95%±0.01 Al10 | P a g
  6. 6. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 1, No.1, 2011PO4, and75.04%±0.01H12 IP6. Additionally, increasing WTRs application rate up to 40 increased the proportion of Al hydroxide with P-sorbed(61.13%±0.02) in Kafr El-Dawarsoil and the other forms of P were 38.91%±0.02 Cd6IP6.However, the proportion of Al hydroxide withP-sorbed (14.68%±0.02) was lower in El-Bostan soil than that of Kafr El-Dawar soil. Also, the other Pforms were 3.40%±0.02 Cu3(PO4)2, 49.16%±0.02 Hydroxyapatite, and 32.74%±0.02 Al Fe PO4.While,the P speciation in Borg Al-Arab soil were completely different at the high rate of WTRs, the bestlinear combination fits were 38.96%±0.02 Ba6IP6, 46.26%±0.01 Cu3(PO4)2, and 14.79%±0.03Cd6IP6(Fig.2 and Table 3).In comparison, in the 50 gkg-1biosolids-treated Troy soil, application of 40gkg-1 DWTRs have changed the P speciation in soil in comparison with control soil(Fig.3 and Table 3).The best linear combination fits were 76.67%±0.05 Ba6IP6, and 23.33%±0.01 Cu3(PO4)2 .Other studieshave different results on P speciation, for examples the study of Beachemin et al.,(2003) revealed thatthe XANES results indicated that phosphate adsorbed on Fe- or Al-oxide minerals was present in allsoils, with a higher proportion in acidic than in slightly alkaline samples. Calcium phosphate alsooccurred in all soils, regardless of pH. In agreement with chemical fractionation results, XANES datashowed that Ca-phosphate was the dominant P forms in one acidic (pH 5.5) and in the two slightlyalkaline (pH 7.4-7.6) soil samples. X-ray absorption near edge structure spectroscopy directlyidentified certain forms of soil P, while chemical fractionation provided indirect supporting data andgave insight on additional forms of P such as organic pools that were not accounted for by the XANESanalysis. Gungr et al.. (2007) studied the P speciation in raw and anaerobically digested dairy manurewith an emphasis on the Ca and Mg phosphate phases. Qualitative analysis of P by XANES spectraindicated that the Ca orthophosphate phases, except dicalcium phosphate anhydrous (DCPA) ormonetite(CaHPO4), were not abundant in dairy manure. Linear combination fitting (LCF) of the Pstandard compounds showed that 57 and 43 % of P was associated with DCPA and struvite,respectively, in the raw manure. In anaerobically digested sample, 78.2% of P was present as struviteand 21.8% of P was associated with Hydroxyapatite (Hap).the P speciation shifted toward Mgorthophosphates and least soluble Ca orthophosphates following anaerobic digestion. Similaritybetween the aqueous orthophosphate, newberyite (MgHPO4.3H2O), and struvite spectra can causeinaccurate P speciation determination when dairy manure is analyzed solely using P XANESspectroscopy; however, XANES can be used in conjunction with XRD to quantify the distribution ofinorganic P species in animal manure. Sato et al.,(2005) reported that P XANES spectra of poultrymanure showed no evidences of crystalline P minerals but dominance of soluble CaP species and freeand weakly bound phosphates(aquoues phosphate and phosphate adsorbed on soil minerals).Phosphatein unamended neighboring forest soil(pH 4.3) was mainly associated with iron compounds such asstrengite and Fe-oxides. Soils with a short-term manure history contained both Fe-associatedphosphates and soluble CaP species such as dibasic calcium phosphate (DCP) and amorphous calciumphosphate (ACP). Long term manure application resulted in a dominance of CaP forms, however, noneof the manure-amended soils showed the presence of crystalline CaP. Seiter et al.(2008) studied the Pspeciation in alum-amended poultry litter, and the results indicated that traditional sequentialfractionation procedures may not account for variability in P speciation in heterogeneous animalmanures. XANES analysis showed that P is present in inorganic (P sorbed on Al oxides, calciumphosphates) and organic forms (phytic acid, polyphosphates, and monoesters) in alum- and non-alum-amended poultry litter.4. ConclusionRevealing the complex nature of phosphate chemistry within environmental samples is an analyticalchallenge requiring new techniques and analytical approaches. Studies using sequential chemicalextractions and nuclear magnetic resonance techniques have provided a wealth of information on bulkscale biosolids phosphorus composition. Speciation provides valuable information about the fate P maytake in the soil and water environment. Phosphorous compounds found in biosolids werepredominately the PO4 sorbed to Al hydroxide, followed by β-tricalcium phosphate, hydroxyapatite,and phytic acid. The addition of WTRs increased the proportion of PO4 sorbed to Al hydroxide andincreased the proportion of aluminum phosphate. Addition of WTRs modified the P speciation inbiosolids-amended soils, and the changes varied depending on the specific P speciation and biosolidsand WTRs application rates. The P speciation in 4.11 | P a g
  7. 7. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 1, No.1, 20115.AknolowdgementThe authors are grateful to the Synchrotron Radiation Center (SRC) for the beamtime award (to Zhangand Lin) with the Canadian Synchrotron Radiation Facility (CSRF). SRC is financially supported bythe National Science Foundation (DMR-0084402), and CSRF is supported by National ResearchCouncil and NSERC (MFA) of CanadaReferencesAjiboye, B., Akinremi,O.O.,Hu,Y. & Flaten,D.N. (2007), “Phosphorus Speciation of SequentialExtracts of Organic Amendments Using Nuclear Magnetic Resonance and X-ray Absorption Near-EdgeStructure Spectroscopies”, Journal of Environmental. Quality 36,1563-1576.Balkcom, K. S., Adams,J.F. & Hartzog,D.L(.2003), “Peanut Yield Response to Poultry Litter andMunicipal Sludge Application”, Communication in Soil Science and. Plant Analysis 34, 801-814.Basta, N.T., Zupancic,R.J. & Dayton, E.A.(2000), “Evaluating Soil tests to Predict BermudagrassGrowth in Drinking Water Treatment Residuals with Phosphorus Fertilizer”, Journal of Environmental.Quality 29,2007-2012.Beauchemin,S.,Hesterberg,D.Chou,J.,Beauchemin,M.Simard,R.R.,&Sayers,D.E.(2003).”Speciation ofPhosphorus in Phosphorus-Enriched Agricultural Soils using X-ray Absorption Near-Edge StructureSpectroscopy and Chemical Fractionation” Journal of Environmental. Quality 32(5),1809-1819.Bloom,P.R., Mr Weave,R.,& Mcbride,M.B.(1978),”The Spectrophotometric and FlurometricDetermination of Aluminum with 8-Hydroxyquinoline and Butyl Acetate Extraction”, Soil ScienceSociety. of America Journal 42,712-716.Brink, G. E.,Rowe,D.E.,& Sistani,K.R.(2002) “Broiler Litter Application Effects on Yield and NutrientUptake of ‘Alicia’ Bermuda grass”, Agronomy Journal 94, 911-916.Cooperband, L.,Bollero,G. & Coale,F.(2002), “Effect of Poultry Litter and Composts on Soil Nitrogenand Phosphorus Availability and Corn Production. Nut. Cycl. Agroecosys. 62,185-194.Daniel, T. C., N.Sharpley,A., & Lemunyon,J.L.(1998),”Agricultural Phosphorus and Eutrophication: ASymposium Overview”, Journal of Environmental. Quality 27,251-257.Day, P.R.(1965), “Particle Fraction and Particle Size Analysis”, in Black,C.A.,Evans,D.D.,Ensminger,L.E., White,J.L.,& Clark,F.E.(eds), Methods of Soil Analysis (Part I). American Society ofAgronomy, Madison, Wisconsin, USA. pp: 545—566.Edwards, D. R., & Daniel,T.C.(1992), “Environmental Impacts of On-Farm Poultry Waste Disposal-Areview”, Bioresearch Technology 41,9-33.Eghball, B. & Power,J.F.(1999), “Phosphorus- and Nitrogen-based Manure and Compost Applications:Corn Production and Soil Phosphorus”, Soil Science Society. of America Journal 63, 895-901.Elliott, H.A., O’Connor, G.A., & Brinton, S.(2002),”Waste Management: Phosphorus Leaching fromBiosolid-Amended Sandy Soils”, Journal of Environmental. Quality. 31,681-689.Evers, G.(1998),”Comparison of Broiler Poultry and Commercial Fertilizer for Coastal BermudagrassProduction in the Southeastern US”, Journal. Sustainable Agriculture. 12,55-77.Gungr,K.,Jurgensen,A.,& Karthikeyan,K.G.(2007),”Determination of Phosphorus Speciation in DairyManure Using XRD and XANES Spectroscopy”, Journal of Environmental. Quality. 36,1856-1863.Huff, D.L.(2010),”Effects of Co-application of Biosolids and Drinking Water Treatment Residuals onPhosphorus Availability in Agricultural Soils”, MSc, Environmental Science Program,Southern IllinoisUniversity Edwardsville,Edwardsville,Illinois,USA.Jones, J.B.(2001), Laboratory Guide of Conducting Soil Tests and Plant Analysis. CRC Press. NewYork, Washington, D.C.Khare, N., Hesterberg,D. & Martin,J.D.(2005), “XANES Investigation of Phosphate Sorption in Singleand Binary Systems of Iron and Aluminum Oxide Minerals”, Environmental Science &Technology 39(7),2152-2160.Kingery, W. L.,Wood,C.W.,Delaney,D.P.,Williams,J.C.,Mullins,J.L.,&12 | P a g
  8. 8. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 1, No.1, 2011Vansanten,E. (1993),”Implications of Long-Term Land Application of Poultry Litter in Tall FescuePastures” Journal Production Agronomy 6, 390-395.Lindsay, W.L., & Norvell, W.A.(1978),”Development of a DTPA Soil Test for Zinc, Iron, Manganese,and Copper”, Soil Science Society. of America Journal 42, 421-428.Lombi, E., Scheckel,K.G., Armstrong,R.D., Forrester,S., Cutler,J.N.,& Paterson,D. (2006),” Speciationand Distribution of Phosphorus in a Fertilized Soil: A synchrotron-Based Investigation”, Soil ScienceSociety. of America Journal 70, 2038-2048.Makris, K.C., Harris,W.G., O’Connor,G.A., Obreza,T.A.,&Elliott,T.A.(2005), “PhysicochemicalProperties Related to Long-Term Phosphorus Retention by Drinking-Water Treatment Residuals”,Environmental. Science and .Technology 39,4280-4289.McDowell, R. W., & Sharpley,A.N.(2004),” Variation of Phosphorus Leached from PennsylvanianSoils Amended with Manures, Composts or Inorganic Fertilizer” Agr. Ecosys.Environ. 102, 17-27.Nelson, D.W., &Sommers,L.E.(1982),” Total carbon, Organic Carbon and Oorganic Matter”, inPage,A.L., Miller,R.L., &Keeney,D.R.(eds), Methods of Soil Analysis. American Society of Agronomy,Madison, Wisconsin, UAS. pp.539-549.Nelson, R.E.(1982),” Carbonate and gypsum” , in Page,A.L., Miller,R.L., &Keeney,D.R.(eds), Methodsof Soil Analysis. American Society of Agronomy, Madison, Wisconsin, UAS. pp 181--197O’Connor, G.A, & Elliott,H.A.(2002),” Co-application of Biosolids and Water Treatment Residuals”,17th WCSS, 14-21 August 2002, Thailand.Olsen, S.R., &Sommers,L.E.(1982), “Phosphorus” , in Page,A.L., Miller,R.L., &Keeney,D.R.(eds),Methods of Soil Analysis. American Society of Agronomy, Madison, Wisconsin, UAS.pp: 403--427.Peak, D., Sims, J. T., & Sparks, D.L. (2002),” Solid-Waste Speciation of Natural and Alum-AmendedPoultry LitterUusing XANES Spectroscopy. Environmental Science & Technology 36,4253-4261.Pickering, I.J., Brown,Jr.G.E., & Tokunaga,T.K.(1995),” Quantitative Speciation of Selenium in SoilsUsing X-ray Absorption Spectroscopy”,. Environmental Science & Technology 29(9), 2456-2459.Pionke, H. B.,Gburek,W.G., & Sharpley,A.N.(2000),” Critical Source Area Controls on Water Qualityin An Agricultural Watershed Located in the Chesapeake Basin. Ecological Engineering 14, 325-335.Rhoades, J.D.(1982),” Cation Exchange Capacity” , in Page,A.L., Miller,R.L., &Keeney,D.R.(eds),Methods of Soil Analysis. American Society of Agronomy, Madison, Wisconsin, UAS pp:149-157. Richards, L.A.(1954),” Diagnosis and Improvement of Saline and Alkaline Soils. USDA. Handbook60.US Government Printing Office, Washington, DC.SAS Institute. (1994).” SAS/STAT Users Guide”, Version 6.4th edition. SAS Inst., Cary, N.C.Sato,S., Solomon, D. Hyland, C. Ketterings, Q.M., & Lehmann, J.(.2005),” Phosphorus Speciation inManure and Manure-Amended Soils Using XANES Spectroscopy”, Environmental Science&Technology., 39(19), 7485-7491.Seiter, J.M., Staats-Borda,K.E.,Ginder-Vogel,M., & Sparks,D.(2008),” XANES Spectroscopic Analysisof Phosphorus Speciation in Alum-Amended Poultry Litter”, Journal of Environmental Quality 37,477-485.Sharpley, A. N.,McDowell,R.W., & Kleinman,P.J.A.(2001),” Phosphorus Loss from Land to Water:Integrating Agricultural and Environmental Management”, Plant Soil 237, 287-307.Shober, A.L., Hesterberg,D.L., Sims,J.T. & Gardner,S.(2006),” Characterization of Phosphorus Speciesin Biosolids and Manures Using XANES Spectroscopy”, Journal of Environmental Quality. 35,:1983-1993.Smith, K. A.,Jackson,D.R& Withers,P.J.A.(2001),” Nutrient Losses by Surface Runoff Following theApplication of Organic Manures to Arable Land”, Environmental Pollution 112, 53-60.Staats, K.E., Arai,Y., & Sparks,D.L.(2004),”Alum Amendment Effects on Phosphorous Release andDistribution in Poultry Litter-Amended Sandy soils”, Journal of Environmental Quality.33, 1904-1911.Tan, K.H.(1996), Soil Sampling, Preparation, and Analysis. Marcel Dekker, Inc. New York. Basel.Hong Kong.13 | P a g
  9. 9. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 1, No.1, 2011U.S. Environmental Protection Agency.(1981),”Process Design Manual- Land Treatment of MunicipalWastewater”; EPA 625/1-81-013; Center for Environmental Research Information: Cincinnati,OH,Ure, A. M.(1995),” Methods of Soil Analysis for Heavy Metals in Soils”, in Alloway,B.J.(ed) ,HeavyMetals in Soils,(2nd Edition). Blackie Academic and Professional, London, pp:58-95Webb, S. M.(2005),” SIXPack: A graphical User Interface for XAS Analysis Using IFEFFIT”. Phys.Scr., T115, 1011–1014.Table 1.Some physical and chemical characteristics of studied soils, WTRs and biosolids in EgyptCharacteristics Units Kafr El- El-Bostan Borg Al- WTRs Biosolids Dawar ArabpH 8.13 ± 0.05a) 7.69 ± 0.05 8.08 ± 0.06 7.45 ± 0.06 6.69 ± 0.03 -1EC dSm 2.66 ± 0.11 3.84 ± 0.12 2.92 ± 0.06 1.67 ± 0.04 11.25 ± 0.12CaCO3 g kg-1 57.90 ± 0.60 2.40 ± 0.30 356.80 ± nd c) nd 2.60Sand g kg-1 596.4 ± 4.20 868.2 ± 5.10 740.00 ± nd nd 3.70Silt g kg-1 141.3 ± 1.50 25.10 ± 0.30 101.50 ± nd nd 1.90Clay g kg-1 262.30 ± 3.70 106.70 ± 158.50 ± nd nd 2.20 3.20Texture S.C.L L.S S.L nd ndO.M b) g kg-1 8.50 ± 0.15 1.00 ± 0.04 4.60 ± 0.15 57.00 ± 450.00 ± 2.00 1.67KCl-Al mg kg-1 1.03 ± 0.04 0.13 ± 0.02 0.08 ± 0.02 28.18 ± 4.22 ± 0.13 1.03Olsen-P mg kg-1 24.75 ± 0.25 2.89 ± 0.14 18.70 ± 0.80 24.00 ± 48.60 ± 1.62 2.00CEC Cmol(+)kg- 39.13 ± 0.98 8.70 ± 0.20 26.00 ± 2.02 34.78 ± 73.57 ± 0.51 1 0.34Total Elements:N g kg-1 nd nd nd 4.20 ± 0.13 32.00 ± 1.56P g kg-1 nd nd nd 1.90 ± 0.15 4.60 ± 0.12K g kg-1 nd nd nd 2.20 ± 0.21 1.90 ± 0.08Al g kg-1 nd nd nd 38.01 ± 3.10 ± 0.23 0.93Ni mg kg-1 25.01 ± 0.02 14.00 ± 0.11 17.02 ± 0.03 9.40 ± 0.07 108.00 ± 1.01Pb mg kg-1 35.08 ± 0.17 14.00 ± 0.11 62.20 ± 0.35 76.00 ± 143.00 ± 0.17 0.64Cu mg kg-1 30.22 ± 0.79 43.21 ± 0.22 24.06 ± 0.07 49.00 ± 128.00 ± 0.02 0.44Cd mg kg-1 3.30 ± 0.18 2.10 ± 0.11 4.50 ± 0.03 3.00 ± 0.02 4.00 ± 0.15DTPA-ExtractableMetals:Ni mg kg-1 8.92 ± 0.04 5.13 ± 0.05 7.17 ± 0.05 2.49 ± 0.07 12.12 ± 0.24Pb mg kg-1 6.13 ± 0.02 2.18 ± 0.08 5.69 ± 0.12 1.58 ± 0.04 62.13 ± 0.22Cu mg kg-1 9.09 ± 0.03 3.13 ± 0.05 4.98 ± 0.03 1.20 ± 0.1 11.83 ± 0.15Cd mg kg-1 0.33 ± 0.02 0.18 ± 0.02 0.26 ± 0.04 0.09 ± 0.02 0.72 ± 0.04a) Means of three samples ± SD.b) O.M: organic matter; S.C.L: sandy clay loam, L.S: loamy sand, S.L: sandy loamc) nd: not determinedTable 2. General properties of the experimental biosolids, WTRs, and soils in Illinois, USA. Values aremeans ± standard deviation (n = 3)Characteristics Units WTRs Biosolids Soil14 | P a g
  10. 10. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 1, No.1, 2011pH 9.00±0.05 11.9±0.2 6.27±0.12 -1EC dSm 1.88±0.05 6.15±0.11 1.05±0.07Texture nd nd Silty loam -1O.M g kg 67.6±0.5 380.2±3.2 20.3±0.6 -1Available-N mg kg 19.06±1.56 78.09±1.05 23.34±0.59 -1KCl-Al mg kg 125.07±4.5 34.67±0.58 75.23±1.52 -1Available-P mg kg 17.12±0.54 53.99±2.51 26.00±4.00 -1CEC cmol(+)kg 43.12±5.54 76.00±3.5 10.53±0.06ICP-MS analysis: -1Aluminum (Al) g kg 12.6±0.05 71.9±0.7 71.0±0.47 -1Sodium (Na) g kg 0.5±0.02 1.5±0.02 <0.001 -1Iron (Fe) g kg 121.0±4.0 82.3±2.9 123.2±4.9 -1Potassium (K) g kg 0.5±0.01 30.7±0.8 10.6±0.6 -1Magnesium (Mg) g kg 12.6±0.5 3.6±0.3 1.5±0.02 -1Silver (Ag) mg kg <0.002 2.00±0.12 <0.002 -1Arsenic (As) mg kg <0.1 11.51±0.26 3.80±0.19 -1Boron (B) mg kg 12.30±0.58 109.07±5.06 6.55±1.05 -1Calcium (Ca) mg kg 266.07±2.28 309.34±11.28 1.61±0.06 -1Cadmium (Cd) mg kg 0.05±0.00 1.57±0.06 0.37±0.03 -1Cobalt (Co) mg kg 0.44±0.04 3.00±0.02 7.53±0.37 -1Chromium (Cr) mg kg 3.83±0.08 23.72±0.69 12.82±0.59 -1Copper (Cu) mg kg 0.86±0.10 342.07±6.70 11.34±0.60 -1Manganese (Mn) mg kg 7021.85±279.71 3321.74±63.71 7822.82±444.63 -1Molybdenum (Mo) mg kg 0.03±0.04 4.60±0.18 0.45±0.07 -1Nickel (Ni) mg kg 7.75±0.71 30.15±0.59 13.50±0.55 -1Lead (Pb) mg kg 0.05±0.00 29.16±0.32 20.30±0.54 -1Zinc (Zn) mg kg 10.95±0.85 190.86±0.83 64.19±2.15Table 3.Relative proportion of phosphate that best fit biosolids, WTRs, and selected WTRs-Biosolids-treated soils XANES spectra in linear combination fittinga. Soil Treatments WTRs Biosolids Kafr El-Dawar El-Bostan Borg Al-Arab USA-soil 5.07%±0.05 Al hydroxide 26.03%±0.01 with P- Ba6IP6 sorbed 64.19%±0.07 Fe hydroxide 73.09%±0.03 with P- Cu3(PO4)2 sorbed 0.89%± 0.02 Al hydroxide 30.72%±0.02 with P- H12IP6 sorbed 47.02%±0.05 19.08%±0.02 31.16%±0.02 Zn3 amorphous Fe- Na12 I P6 (PO4)2 phosphate 10 0.79%±0.02 10.93%±0.01 12.63%±0.01Biosolids(B) Mn3 (PO4)2 KH2PO4 Al PO4 17.21%±0.01 11.22%±0.04 3.10%±0.02 Hydroxyapatite KMgH9IP6 Cu3(PO4)215 | P a g
  11. 11. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 1, No.1, 2011 16.13%±0.01 7.26%±0.01 Al hydroxide 13.16%±0.02 Cu3(PO4)2 with P-sorbed Hydroxyapatite 11.37%±0.02 57.98%±0.01 8.70%±0.04 Al Fe hydroxide with Hydroxyapatite Fe PO4 P-sorbed 3.67%±0.03 15.58%±0.03 H12 IP6 CaH10P6 12.90%±0.03 H12 IP6 83.82%±0.01 45.36%±0.02 79.74%±0.01 Al hydroxide Al PO4 Al PO4 with P-sorbed 4.12%±0.01 16.19%±0.01 51.17%±0.01 Al hydroxide with Al Fe PO4 H12 IP610B+10WTRs P-sorbed 10.74%±0.01 3.45%±0.02 Fe hydroxide with Al Fe PO4 P-sorbed 5.39%±0.01 Al Fe PO4 76.45%±0.01 8.65%±0.02 23.62%±0.05 Al PO4 Al PO4 Al PO4 23.53%±0.01 58.72%±0.01 46.37%±0.02 H12 IP6 H12 IP6 Hydroxyapatite10B+40WTRs 3.18%±0.04 32.62%±0.02 Fe hydroxide with Al Fe PO4 P-sorbed 26.81%±0.0 H12 IP6 15.34%±0.02 32.27%±0.02 amorphous Al- 14.84%±0.005 amorphous Al- phosphate Al PO4 phosphate 29.53%±0.01 19.51%±0.03 21.39%±0.01 Al PO4 CaH10P6 Al PO4 39.67%±0.02 65.64%±0.02 17.61%±0.01 30B CaH10P6 H12 IP6 Hydroxyapatite 21.01%±0.02 15.46%±0.02 Amm.magnesium H12 IP6 phosphate 1.62%±0.01 K4Mg2H4IP6 6.07%±0.01 Al Fe PO4 14.27%±0.02 18.86%±0.05 24.95%±0.01 Ca3 (PO4)2 Ca3 (PO4)2 Al PO4 71.49%±0.02 47.23%±0.04 75.04%±0.01 Hydroxyapatite Hydroxyapatite H12 IP630B+10WTRs 14.23%±0.004 5.35%±0.03 Al Fe PO4 CaH10P6 28.55%±0.02 H12 IP630B+40WTRs 61.13%±0.02 3.40%±0.02 38.96%±0.0216 | P a g
  12. 12. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 1, No.1, 2011 Al hydroxide Cu3(PO4)2 Ba6IP6 with P-sorbed 38.91%±0.02 49.16%±0.02 46.26%±0.01 Cd6 IP6 Hydroxyapatite Cu3(PO4)2 14.68%±0.02 14.79%±0.03 Al hydroxide Cd6IP6 with P-sorbed 32.74%±0.02 Al Fe PO4 13.50%±0.06 K Mg Hg IP6 47.50%± 0.02 50B Fe hydroxide with P-sorbed 38.80% ±0.04 H12IP6 76.67% ±0.05 Ba6IP650B+40WTRs 23.33% ±0.10 Cu3(PO4)2a Percentage after normalization to sum= 100 ± standard errors for the linear coefficients. Biosolids 6 Al hydroxide with P-sorbed Cu3(PO4)2 Data 5 Ba6IP6 Fit Normalized Absorption 4 3 2 1 0 2140 2160 2180 2200 2220 Energy (eV)17 | P a g
  13. 13. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 1, No.1, 2011 DWTR 5 Al hydroxide with P-sorbed H12 IP6 Fe hydroxide with P-sorbed Data 4 FitNormalized Absorption 3 2 1 0 2140 2160 2180 2200 2220 Energy (eV) Figure 1. Phosphorus K-edge XANES spectra for biosolids and WTRs of Egypt.18 | P a g
  14. 14. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 1, No.1, 2011 30 Biosolids + 40 DWTR-Borg Al-Arab soil 6 Cu3 (PO4)2 Cd6 I P6 5 Data Ba6 I P6 Normalized Absorption Fit 4 3 2 1 0 2140 2160 2180 2200 2220 Energy(eV) 30 Biosolids+40 DWTR -Kafr El-Dawar soil 7 Al hydroxide with P-sorbed Cd6 IP6 6 Data Fit Normalized Absorption 5 4 3 2 1 0 2140 2160 2180 2200 2220 Energy(eV) 30 Biosolids+40 DWTR- El-Bostan soil 5 Al hydroxide with P-sorbed Cu3 (PO4)2 Hydroxylapatite 4 Data Al/Fe PO4 Normalized Absorption Fit 3 2 1 0 2140 2160 2180 2200 2220 Energy(eV)Figure 2. Phosphorus K-edge XANES spectra for 30 biosolids-treated Egyptian soils amendedwith 40 WTRs.19 | P a g
  15. 15. Journal of Environment and Earth Science www.iiste.orgISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)Vol 1, No.1, 2011 50 Biosolids 50 biosolids + 40 DWTRs 4 8 Ca H10 hexaphosphate H12 Z hexaphosphate Cu3(PO4)2 Fe hydroxide with P sorbed data data B6 Inositol hexaphosphate 3 fit 6 fitNormalized Absorption Normalized Absorption 2 4 1 2 0 0 2140 2160 2180 2200 2220 2140 2160 2180 2200 2220 Energy (eV) Energy (eV)Figure 3. Phosphorus K-edge XANES spectra for 50 and 50 and 40 Troy soils.20 | P a g