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1
Khassenov, A. K., U. B. Nussupbekov, D. Zh Karabekova, S. S. Kassymov, M. M. Bolatbekova i M. Stoev. "Investigation of the effect of electro-hydraulic pulses on the combustion process of phosphorus sludge". Bulletin of the Karaganda University. "Physics" Series 100, nr 4 (30.12.2020): 71–77. http://dx.doi.org/10.31489/2020ph4/71-77.
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The article considers the influence of electro-hydraulic pulses on the combustion of phosphorus sludge. Electric discharges in the environment of phosphorus sludge are sources of shock waves, which destroying the structure of phosphorus sludge and contribute to the intensification of the combustion process. A distinctive feature of the electro-hydraulic effect is the ability to control the parameters of pressure waves over a fairly wide range using the characteristics of the electric discharge circuit. For determine the optimal productivity and purity of the final product of the electric discharge unit’s operation mode, experiments were conducted on the effect of the discharge energy on the efficiency of the electric discharge method for extracting phosphorus from phosphorus sludge. The efficiency of the electric discharge process was estimated by the amount of phosphorus that was released after settling and expressed as a percentage of the total amount of phosphorus in a phosphorus sludge’s portion. The experiments were conducted out for sludges of different structures, with different phosphorus content and were conditionally divided into three groups: “rich” with phosphorus content — 70 %, “medium” — 50 % and “poor” — phosphorus content — 30 %.
2
Fukase, T., M. Shibata i Y. Miyaji. "The Role of an Anaerobic Stage on Biological Phosphorus Removal". Water Science and Technology 17, nr 2-3 (1.02.1985): 69–80. http://dx.doi.org/10.2166/wst.1985.0120.
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A detailed study was conducted on biological removal of phosphorus by an activated sludge process composed of an anaerobic stage followed by an aerobic stage in order to clarify the role of the anaerobic stage of the process. Two distinctive sludges, one contained approximately 10 percent phosphorus, most of which existed in the form of polyphosphates, and the other contained 1.9 percent phosphorus, were obtained by changing BOD concentration of influent and hydraulic detention time of the process. Although the polyphosphate-containing sludge released phosphorus in proportion to the absorbed BOD at anaerobic conditions, the sludge which did not contain polyphosphates also absorbed an equal amount of BOD at the identical rate without any external sources of oxygen. Both sludges accumulated identical levels of poly-β-hydroxybutyrate within the sludges as the BOD sources were absorbed. These results suggest that the polyphosphate-containing sludges have no advantage over the sludges with no polyphosphates when they uptake BOD in the anaerobic stage.
3
Erdincler, A., i L. D. Seyhan. "Agricultural use of municipal wastewater sludges: phosphorus availability of biological excess phosphorus removal sludges". Water Science and Technology 54, nr 5 (1.09.2006): 131–38. http://dx.doi.org/10.2166/wst.2006.555.
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Reuse of sewage sludges as phosphorus fertiliser requires the estimation of the plant availabilities of phosphorus (P) from different sludges. This study investigates the effect of lime stabilisation on the phosphorus availability from biological phosphorus removal sludges. In the first part of the study, pot experiments were carried out to assess the fertilising effect of a dewatered biological phosphorus removal sludge. Availability of P was determined in terms of plant-uptake. In the second part of the study, incubation tests were carried out to observe the change in the available P with time when the waste activated sludge (WAS) from an enhanced biological phosphorus removal (EBPR) process is mixed with the same soil. In this part, the plant available P was measured in terms of Olsen extractable P. A P-deficient, alkaline soil was used in the experiments and Lollium Perenne was selected as the testing plant. The results of the pot experiments revealed that lime-stabilisation of the sludge considerably decreased or retarded the availability of P in the sludge. In the incubation tests, the availability of phosphorus in the lime stabilised and non-stabilised sludge amended soil samples was close to each other. In general, P-availability was increased due to the sludge application except for the lime-stabilised dewatered sludge.
4
Bond, Philip L., Jürg Keller i Linda L. Blackall. "Bio-P and non-bio-P bacteria identification by a novel microbial approach". Water Science and Technology 39, nr 6 (1.03.1999): 13–20. http://dx.doi.org/10.2166/wst.1999.0249.
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Culturing bacteria from activated sludge with enhanced biological phosphorus removal (EBPR) has strongly implicated Acinetobacter with the process. However, using fluorescent in-situ hybridisation (FISH) probing to analyse microbial populations, we have shown evidence opposing this widespread belief. We describe the phosphorus (P) removing performance and microbial population analyses of sludges obtained in a laboratory scale EBPR reactor. Two sludges with extremely high P removing capabilities were examined, the P content of these sludges was 8.6% (P sludge) and 12.3% (S sludge) of the MLSS. Identification of bacteria using FISH probing indicated both sludges were dominated by microbes from the beta proteobacteria and high mol% G+C Gram positive bacteria. Acinetobacter could make up only a small proportion of the cells in these sludges. Sludge with extremely poor P removal (P content of 1.5%, referred to as T sludge) was then generated by reducing the P in the influent. Bacteria resembling the G-bacteria became abundant in this sludge and these were identified using FISH probing. The anaerobic transformations of the T and P sludges correlated well with that of the non-EBPR and EBPR biological models respectively, indicating that bacteria in the T sludge have the potential to inhibit P removal in EBPR systems.
5
Giacobbo, Francesca, Mirko Da Ros, Elena Macerata i Eros Mossini. "A case study of management and disposal of TENORMs: radiological risk estimation by TSD Dose and RESRAD-ONSITE". AIMS Environmental Science 8, nr 5 (2021): 465–80. http://dx.doi.org/10.3934/environsci.2021030.
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<abstract> <p>Naturally Occurring Radioactive Materials (NORMs) and Technologically Enhanced NORMs (TENORMs) are among the principal sources of radiation exposure for humans and for the environment. Therefore, the assessment of the impact of NORMs and TENORMs waste on human health is a key issue for their management and for acceptance of disposal sites. The radiological doses to workers and public due to TENORMs disposal depend on the waste inventory, on the usage of the site during operational activities and post closure phase and on the presence of dwelling areas in the vicinity of the disposal site. In the present study it is presented a methodology to preliminary assess the feasibility of a disposal of TENORMs, mainly constituted by phosphate sludges, originated from phosphoric acid industry activities. The hypothetical case study here presented is inspired by a real case study. Different possible scenarios have been considered. The potential doses to workers and to the public on-site have been estimated by the use of the TSD Dose and the RESRAD on-site codes both during the production life cycle of the site and once it ended. Sensitivity analyses were conducted to evaluate the impact of some key parameters, such the coverage thickness and wind velocity, on potential risk for workers and public.</p> </abstract>
6
Tonkovic, Zlatko. "Aerobic stabilisation criteria for BNR biosolids". Water Science and Technology 38, nr 2 (1.07.1998): 133–41. http://dx.doi.org/10.2166/wst.1998.0123.
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A research program was undertaken to establish the stability of waste activated sludge generated from seven activated sludge treatment plants, both nutrient removal and conventional, and determine what further treatment is required to produce a substantially stabilised (ie. non-odorous) sludge. It has been previously thought that waste activated sludge from extended aeration plants (sludge age of approximately 25 days) was sufficiently stabilised to permit dewatering and stockpiling without odour generation. However, experience at a number of treatment plants with large unaerated mass fractions for biological removal of nitrogen and phosphorus has demonstrated that these sludges are generally odorous. With the increasing requirement for on-site storage of sludge to remove pathogens prior to sludge re-use, odour generation from secondary sludges has the potential to pose significant environmental problems for many treatment plants. The objective of the research program was to quantify the degree of stabilisation achieved in various activated sludge treatment plants, what additional aerobic treatment is required to achieve a stabilised sludge and what are the readily identified characteristics of a stabilised sludge, including volatile solids content, specific oxygen uptake rate and pathogen destruction. The phosphorus leaching characteristics were also compared between various sludges and between continuous and intermittent aerobic digestion process.
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Tonkovic, Zlatko. "Aerobic stabilisation criteria for BNR biosolids". Water Science and Technology 39, nr 6 (1.03.1999): 167–74. http://dx.doi.org/10.2166/wst.1999.0290.
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A research program was undertaken to establish the stability of waste activated sludge generated from several activated sludge treatment plants, both nutrient removal and conventional, and determine what further treatment is required to produce a substantially stabilised (ie. non-odorous) sludge. It has been previously thought that waste activated sludge from extended aeration plants (sludge age of approximately 25 days) was sufficiently stabilised to permit dewatering and stockpiling without odour generation. However, experience at a number of treatment plants with large unaerated mass fractions for biological removal of nitrogen and phosphorus has demonstrated that these sludges are generally odorous. With the increasing requirement for on-site storage of sludge to remove pathogens prior to sludge re-use, odour generation from secondary sludges has the potential to pose significant environmental problems for many treatment plants. The objective of the research program was to quantify the degree of stabilisation achieved in various activated sludge treatment plants, what additional aerobic treatment is required to achieve a stabilised sludge and what are the readily identified characteristics of a stabilised sludge, including volatile solids content, specific oxygen uptake rate and pathogen destruction. The phosphorus leaching characteristics were also compared between various sludges and between continuous and intermittent aerobic digestion processes.
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Li, Qianlan, Qingdan Wu, Xiaochen Zheng, Pengfei Wang, Dongsheng Zou, Fen Liu i Zhihua Xiao. "The Conversion and Migration Behavior of Phosphorus Speciation During Pyrolysis of Different Sludges". AIMS Environmental Science 11, nr 1 (2024): 1–20. http://dx.doi.org/10.3934/environsci.2024001.
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<abstract> <p>The study was enforced to probe the conversion and migration behavior of phosphorus speciation in sludge and the biochar received from pyrolysis of municipal sludge (MS), town sludge (TS), and slaughterhouse sludge (SS). This study creatively used fractionation of soil phosphorus to further differentiate speciation of phosphorus in three sludges (MS, TS, and SS). According to the x-ray diffraction (XRD) analysis and sequential extraction, the study proved the dependence of P speciation conversion on pyrolysis temperature and different types of raw sludge. The results of P-fractionation indicated that Ca-bound IP (Ca-IP) content in all biochars significantly increased at pyrolysis temperature of 350–800 ℃, and the proportion of soluble and loosely bound IP (SL-IP), aluminum-bound IP (Al-IP), and Fe-bound IP (Fe-IP) of MS and SS decreased. The difference is that the Al-IP in the TS increased slightly as the pyrolysis temperature increased. Among the three kinds of sludge, the Olsen-P of TS is the lowest because the content of Olsen-P in sludge will decrease with the decrease of pH in the process of sewage treatment after acidification. In addition, XRD patterns of three sludges and biochar further confirmed the low crystallinity of AlPO<sub>4</sub> minerals. Through in-depth research on the environmental behavior of phosphorus, this study might additionally provide essential knowledge for the recovery and utilization of phosphorus in sludge.</p> </abstract>
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Crocetti, Gregory R., Philip Hugenholtz, Philip L. Bond, Andrew Schuler, Jürg Keller, David Jenkins i Linda L. Blackall. "Identification of Polyphosphate-Accumulating Organisms and Design of 16S rRNA-Directed Probes for Their Detection and Quantitation". Applied and Environmental Microbiology 66, nr 3 (1.03.2000): 1175–82. http://dx.doi.org/10.1128/aem.66.3.1175-1182.2000.
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ABSTRACT Laboratory-scale sequencing batch reactors (SBRs) as models for activated sludge processes were used to study enhanced biological phosphorus removal (EBPR) from wastewater. Enrichment for polyphosphate-accumulating organisms (PAOs) was achieved essentially by increasing the phosphorus concentration in the influent to the SBRs. Fluorescence in situ hybridization (FISH) using domain-, division-, and subdivision-level probes was used to assess the proportions of microorganisms in the sludges. The A sludge, a high-performance P-removing sludge containing 15.1% P in the biomass, was comprised of large clusters of polyphosphate-containing coccobacilli. By FISH, >80% of the A sludge bacteria were β-2 Proteobacteria arranged in clusters of coccobacilli, strongly suggesting that this group contains a PAO responsible for EBPR. The second dominant group in the A sludge was the Actinobacteria. Clone libraries of PCR-amplified bacterial 16S rRNA genes from three high-performance P-removing sludges were prepared, and clones belonging to the β-2 Proteobacteria were fully sequenced. A distinctive group of clones (sharing ≥98% sequence identity) related to Rhodocyclus spp. (94 to 97% identity) andPropionibacter pelophilus (95 to 96% identity) was identified as the most likely candidate PAOs. Three probes specific for the highly related candidate PAO group were designed from the sequence data. All three probes specifically bound to the morphologically distinctive clusters of PAOs in the A sludge, exactly coinciding with the β-2 Proteobacteria probe. Sequential FISH and polyphosphate staining of EBPR sludges clearly demonstrated that PAO probe-binding cells contained polyphosphate. Subsequent PAO probe analyses of a number of sludges with various P removal capacities indicated a strong positive correlation between P removal from the wastewater as determined by sludge P content and number of PAO probe-binding cells. We conclude therefore that an important group of PAOs in EBPR sludges are bacteria closely related toRhodocyclus and Propionibacter.
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Stypka, T., E. Plaza, A. Stypka, J. Trela i B. Hultman. "Regional planning and product recovery as tools for sustainable sludge management". Water Science and Technology 46, nr 4-5 (1.08.2002): 389–96. http://dx.doi.org/10.2166/wst.2002.0633.
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The article presents two aspects of sludge management: regional planning and product recovery. The introduction of these two elements can reduce the cost, close the ecocycle and make the management more sustainable. A spreadsheet program to optimize the regional location of different facilities is presented. The simple example shows the potential of the model. The brief comparison of formal problems concerning sludge disposal in Poland and Sweden is also discussed. Requirements of phosphorus recovery and recycling of phosphorus to the phosphate industry make sludge fractionation in combination with product recovery a new development in wastewater handling. Phosphorus recovery from sludges with chemical bound phosphorus requires complex and expensive process technology and may therefore lead to increased regional sludge management with a central sludge treatment plant.
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Gorazda, Katarzyna, Zygmunt Kowalski i Zbigniew Wzorek. "From sewage sludge ash to calcium phosphate fertilizers". Polish Journal of Chemical Technology 14, nr 3 (1.10.2012): 54–58. http://dx.doi.org/10.2478/v10026-012-0084-3.
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Our work presents the results of the research on the utilization of ashes after sewage sludge combustion comprising phosphorus recovery in the form of useful products. The investigations were divided into three parts: selecting the combustion parameters of sewage sludge, examining ash leaching with mineral acids (nitric and phosphoric) to high phosphorus selectivity assuring a low content of iron and heavy metals in the extracted solutions and precipitation of CaHPO4 .2H2O. Suitable temperature of a sewage sludge combustion enables selective extraction of phosphorus compounds from ash because of hematite phase forming, insoluble in mineral acids. The extracts from phosphoric acid leaching, where the extraction of phosphorus compounds was 96.1%, have very good properties for its further use as the initial solution for CaHPO4 .2H2O with 6% lime milk. The obtained product is characterized by high purity and phosphorus availability compatible even with the feed phosphate standard.
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Sudiana, I. M., T. Mino, H. Satoh i T. Matsuo. "Morphology, In-Situ characterization with rRNA targetted probes and respiratory quinone profiles of enhanced biological phosphorus removal sludge". Water Science and Technology 38, nr 8-9 (1.10.1998): 69–76. http://dx.doi.org/10.2166/wst.1998.0792.
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The microbial communities in activated sludge acclimated with either acetate or glucose as the major carbon source under phosphorus limited or rich conditions were investigated morphologically, phylogenetically and chemotaxonomically. The sludge with a minimized polyphosphate content was dominated by tetrad shaped bacteria, which were suspected to be ‘glycogen accumulating bacteria (GAOs) or G bacteria’ The sludge containing high polyphosphate was dominated by cluster forming coccus bacteria. Quinone analyses suggested that all the sludge tested contained various ubiquinones and menaquinones, of which the ubiquinones Q-8 and Q-10 were dominant. Analyses with rRNA targeted probes showed that beta sub class of Proteobacteria was most predominant in all sludges tested. Morphological, phylogenetic and chemotaxonomic investigation all indicated that both high and low P sludges are microbiologically diverse.
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T'Seyen, J., D. Malnou, J. C. Block i G. Faup. "Polyphosphate Kinase Activity during Phosphate Uptake by Bacteria". Water Science and Technology 17, nr 11-12 (1.11.1985): 43–56. http://dx.doi.org/10.2166/wst.1985.0220.
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Polyphosphate kinase, one of the key enzymes for polyphosphate accumulation in bacteria, has been investigated in pure culture and activated sludge samples. Three bacterial species (Acinetobacter lwoffi, A. phosphadevorus and Pseudomonas fluorescens) appeared to have a polyphosphate kinase activity (between 0.3 and 4.7 nM of P04 transferred per minute and per mg of proteins). However tests carried out on Aeromonas hydrophila, Bacillus subtilis, E. coli and Serratia sp. showed these species did not have any measurable polyphosphate kinase activity. Enzyme activity in bacteria is dependent on environmental conditions and can be induced, in particular, by anaerobic stress, even without modification of extracellular phosphate concentrations. Most of the activated sludge samples taken from laboratory pilot plants achieving good phosphorus removal did not present any measurable polyphosphate kinase activity. Such poor results can be related to low numbers of phosphorus removing bacteria and inhibitory molecules in sludge extracts. The only observed activity was in pretreated sludges (washed sludges) and in sludges submitted in a batch reator to phosphate starvation. However, in these, enzyme activity was at least 20 times lower than those measured in pure culture of A. lwoffi. Polyphosphate kinase induction is a complicated and time consuming method which has to be used only in the research field. At the present time our results show that sludge phosphate uptake potential cannot be predicted by the measure of induction of polyphosphate kinase activity.
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Oosthuizen, D. J., i T. E. Cloete. "SEM-EDS for determining the phosphorus content in activated sludge EPS". Water Science and Technology 43, nr 6 (1.03.2001): 105–12. http://dx.doi.org/10.2166/wst.2001.0351.
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Not all phosphorus removed in activated sludge systems can be accounted for by polyphosphate accumulating organisms (PAO). A method for the qualitative and quantitative in situ characterization of PAO cell clusters and closely associated extracellular polysaccharides (EPS) is described. X-ray microanalysis was performed on samples from four activated sludge plants situated in Pretoria, South Africa. Analyses were done by means of Scanning Electron Microscopy (SEM) combined with Energy Dispersive Spectrometry (EDS). Cell clusters with associated EPS on average contained between 57 and 59% phosphorus, while EPS alone contained on average between 23 and 30% phosphorus. Results suggest that phosphorus removal in activated sludge might be due not only to PAO, but also by EPS acting as a phosphorus reservoir. Extraction of EPS from two different activated sludge plants yielded different amounts of EPS, which, in combination with SEM-EDS, may shed light on different phosphate uptake abilities of different activated sludges.
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Wilmes, P., i P. L. Bond. "Towards exposure of elusive metabolic mixed-culture processes: the application of metaproteomic analyses to activated sludge". Water Science and Technology 54, nr 1 (1.07.2006): 217–26. http://dx.doi.org/10.2166/wst.2006.390.
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Protein expression is a direct reflection of specific microbial activities in any ecosystem. In order to assess protein expression in mixed microbial communities, the feasibility of applying proteomic techniques to activated sludge samples has recently been demonstrated. We report the application of metaproteomics to two activated sludges from a laboratory-scale sequencing batch reactor with dissimilar phosphorus removal performances. Fluorescence in situ hybridization (FISH) revealed that the sludge with good enhanced biological phosphorus removal performance (EBPR) was dominated by Betaproteobacteria (65% of EUBMIX binding cells) and gave positive signals for the Rhodocyclus-type PAO specific probe (59%). The non-EBPR sludge was dominated by tetrad-forming Alphaproteobacteria (75%). With regard to the proteomic investigation, 630 individual protein spots were matched across the replicate groups of the anaerobic and aerobic phases of the EBPR sludge with 9.4% of all spots being statistically different between the two phases. The non-EBPR metaproteomic maps exhibited 590 matched spots with 14.7% statistical differences between the two phases. Overall, the non-EBPR sludge expressed around 30% more significant differences than the EBPR sludge. The comparison of protein expression in the two sludges showed that their metaproteomes were substantially different and this was reflected in their microbial community structures and metabolic transformations.
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Liang, Haijun, Patrick Zhang, Zhen Jin i David DePaoli. "Rare Earth and Phosphorus Leaching from a Flotation Tailings of Florida Phosphate Rock". Minerals 8, nr 9 (19.09.2018): 416. http://dx.doi.org/10.3390/min8090416.
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Phosphorite, or phosphate rock, is the raw material of phosphoric acid production. It has also been regarded as the most important secondary rare earth element (REE) resource due to low contents of rare earth elements contained in the ore. In Florida, there is about 19 Mt of phosphate rock mined annually. After beneficiation, the phosphate rock concentrate is utilized to produce phosphoric acid via a wet-process in which sulfuric acid is used to digest phosphate. During these processes, REEs and some phosphorus get lost in the byproducts including phosphatic clay, flotation tailings, phosphogypsum (PG), and phosphoric sludge. Recovering REEs and phosphorus from these wastes is beneficial to maximize the utilization of these valuable resources. This study focused on the effects of wet-process operating conditions on REE and phosphorus leaching from a kind of flotation tailing of Florida phosphate rock. The tailings were first beneficiated with a shaking table, and then a series of leaching tests were conducted on the shaking table concentrate. The results indicated that REEs had similar trends of leaching efficiency to those of phosphorus. Under the conditions of 16% phosphoric acid concentration in the initial pulp, a temperature of 75 °C, a stoichiometric ratio of sulfuric acid (H2SO4) to calcium oxide (CaO) of 1.1, and a weight ratio of liquid to solid of 3.5, REE and phosphorus leaching efficiencies reached relatively high values of approximately 61% and 91%, respectively. Analyses indicated that the phosphate ions (PO43−) in the leaching solution tended to combine with REE ions to form REE phosphates which precipitated into PG, but the other large amount of anions such as sulfate ions (SO42−) and fluoride ions (F−) took effect of steric hindrance to prevent PO43− from combining with REE cations. These two opposite effects determined the REE distribution between the leaching solution and PG.
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McMahon, K. D., D. Jenkins i J. D. Keasling. "Polyphosphate kinase genes from activated sludge carrying out enhanced biological phosphorus removal". Water Science and Technology 46, nr 1-2 (1.07.2002): 155–62. http://dx.doi.org/10.2166/wst.2002.0471.
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The community structure and metabolic function of activated sludge carrying out enhanced biological phosphorus removal have been investigated. Laboratory-scale sequencing batch reactors were operated at several influent COD/P ratios to obtain sludges with a range of phosphorus contents. Molecular microbiological techniques based on small subunit ribosomal RNA were used to characterize the community structure of these sludges. The dominant polyphosphate accumulating organism was a close relative of Rhodocyclus tenuis, a member of the β subclass of the Proteobacteria. Fragments of genes coding for polyphosphate kinase (PPK), thought to be responsible for polyphosphate accumulation, were retrieved from one of the sludges. The relative abundance of PPK gene copies in genomic DNA extracted from sludges was determined to confirm that at least one of the PPK gene sequences was derived from the dominant polyphosphate accumulating organism.
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Ichihashi, O., H. Satoh i T. Mino. "Sludge–sludge Interaction in the Enhanced Biological Phosphorus Removal Process". Water Science and Technology 53, nr 6 (1.03.2006): 1–6. http://dx.doi.org/10.2166/wst.2006.161.
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Metabolisms related to enhanced biological phosphorus removal (EBPR) were found to be affected when two activated sludges with different EBPR activities were mixed together. In the present study, two laboratory scale EBPR processes were operated in parallel, one of them with higher and another with lower EBPR activities. The activated sludges from the two reactors were mixed together at different mixing ratios. The supernatant was made the same for all mixing ratios, anaerobic–aerobic batch experiments were performed, and acetate uptake rate and phosphate release rate under anaerobic conditions and phosphate uptake rate under aerobic condition were determined. The metabolic rates measured were expected to be linear to the mixing ratios, as the supernatant was the same for all mixing ratios, whereas the metabolic rates were either promoted or inhibited by mixing of sludges. As an indicator for the sludge mixing effect on the metabolic rates, mixing effect intensity (MEI) was introduced. Chemical substances that are produced by microorganisms in activated sludge are proposed to be one of the possible causes of the sludge mixing effect.
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Hagare, Dharmappa, Woo Taek Hong, Zuhaib Siddiqui, Sai Kiran Natarajan i Julian Fyfe. "Effect of Dairy Pond Sludge/Supernatant Application on Ryegrass Dry Matter Yield and Phosphorus Fractions in Soil". Agriculture 12, nr 3 (28.02.2022): 351. http://dx.doi.org/10.3390/agriculture12030351.
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Pasture yield in dairy grazing systems is critical to supplying sufficient feed for milking cows and maintaining productivity. In the Australian dairy industry, ryegrass and clover are common grasses used in grazed pastures. Dairy shed effluent (DSE), the wastewater produced from washing down the dairy holding yards during and after milking, is generally managed through application to pasture as a fertilizer substitute/supplement following partial treatment in stabilization ponds. The aim of this study is to assess the benefits of applying sludge and supernatant collected from two-stage DSE pond systems to ryegrass pasture. A pot experiment was conducted which involved applying pond sludges and supernatant to soil seeded with ryegrass. The application rates of the pond by-products were set according to their labile (plant available) phosphorus content. Ryegrass yield and leachate generated from each of the pots were recorded, and samples were collected for analysis of nutrients and other parameters. The ryegrass grown in soil treated with pond sludge and supernatant yielded greater dry matter (DM) with higher nutrient content than untreated control pots. In addition, pots treated with pond sludge exhibited lower rates of phosphorus leaching from the soil compared with pots treated with supernatant. Thus, pond sludge retained more plant available phosphorus in soil than both the control and pond supernatant treatment. The potassium to calcium/magnesium ratios in the ryegrass in the pots treated with pond sludge and supernatant were below the recommended upper limit for grazing. Therefore, the application of pond sludges on the dairy paddocks was found to be superior to applying supernatant in terms of utilization and conservation of phosphorus within the dairy farm and presents low risks of groundwater pollution and grass tetany.
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Nazarbek, Ulzhalgas, Perizat Abdurazova, Saule Nazarbekova, Yerkebulan Raiymbekov i Maksat Kambatyrov. "Processing of Phosphoric Solid Waste by Humic Acid Leaching Method". Inorganics 11, nr 3 (21.02.2023): 90. http://dx.doi.org/10.3390/inorganics11030090.
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This article presents the results of research on the leaching of solid phosphorus-containing waste with humic acid. Such waste includes the by-products of the electrothermal processing of phosphate raw materials—phosphorus sludge and cottrel dust. Chemical and X-ray diffraction analyses have been used to study their composition and phase structure, according to which these substances have an amorphous structure. The leaching of phosphoric sludge and cottrel dust was investigated by varying the main parameters. The obtained data were processed using the method of formal kinetics to study the features of the process. The reaction rate constants and the apparent activation energy were calculated, and the values found made it possible to determine that the process under study is limited by diffusion. The scientific novelty of the article is the use of humic acid for leaching phosphoric solid waste as opposed to traditional methods. This new method may offer improved efficiency, reduced environmental impact, and a potential alternative solution for the processing of phosphoric waste.
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Parés Viader, Raimon, Pernille Erland Jensen, Lisbeth M. Ottosen, Tobias P. Thomsen, Jesper Ahrenfeldt i Henrik Hauggaard-Nielsen. "Comparison of phosphorus recovery from incineration and gasification sewage sludge ash". Water Science and Technology 75, nr 5 (28.12.2016): 1251–60. http://dx.doi.org/10.2166/wst.2016.620.
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Incineration of sewage sludge is a common practice in many western countries. Gasification is an attractive option because of its high energy efficiency and flexibility in the usage of the produced gas. However, they both unavoidably produce sewage sludge ashes, a material that is rich in phosphorus, but which is commonly landfilled or used in construction materials. With current uncertainty in phosphate rock supply, phosphorus recovery from sewage sludge ashes has become interesting. In the present work, ashes from incineration and gasification of the same sewage sludge were compared in terms of phosphorus extractability using electrodialytic (ED) methods. The results show that comparable recovery rates of phosphorus were achieved with a single ED step for incineration ashes and a sequential combination of two ED steps for gasification ashes, which was due to a higher influence of iron and/or aluminium in phosphorus solubility for the latter. A product with lower level of metallic impurities and comparable to wet process phosphoric acid was eventually obtained from gasification ashes. Thus, gasification becomes an interesting alternative to incineration also in terms of phosphorus separation.
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Seyhan, D., i A. Erdincler. "Effect of lime stabilisation of enhanced biological phosphorus removal sludges on the phosphorus availability to plants". Water Science and Technology 48, nr 1 (1.07.2003): 155–62. http://dx.doi.org/10.2166/wst.2003.0041.
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This study investigates the phosphorus (P) availability in lime stabilised biological phosphorus removal sludges. Lime-stabilised sludge amendments (LS), non-stabilised sludge amendments (S) and amendments with a chemical fertiliser (TSP) were compared through plant uptake of P and Olsen-extractable P for this purpose. In the first part of the study, pot experiments were performed, where a dewatered biological phosphorus removal sludge was applied to pots at increasing rates of P. A P-deficient, alkaline soil was used in the experiments and Lollium perenne was the testing plant. In the second part (incubation tests), the waste activated sludge from an Enhanced Biological Phosphorus Removal (EBPR) process was mixed with the same soil at a pre-determined P-based rate. The pot experiments showed that, the efficiency of the fertilising materials, based on the minimum P applied to reach the maximum yield, was in the following order: S∼LS>TSP. However, the P concentration in the plant tissue was in the order of TSP>S>LS for all P application rates. In the incubation tests, the EBPR sludge raised the soil P-level from the low range to the medium range. The P-availability in TSP decreased rapidly with time whereas that in S and LS remained almost constant.
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Chukwudebelu, Jane Adamma, i Jonah Agunwamba. "Effect of Different Types of Chemicals, Cooking Time and Chemical Concentration on the Quality of Sludge and Pulp Appearance". Asian Journal of Chemical Sciences 13, nr 1 (28.03.2023): 46–55. http://dx.doi.org/10.9734/ajocs/2023/v13i1232.
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Pulp and paper production process releases different types of wastes into the environment and pulp mill sludge is one of the major wastes from pulp and paper mill. The environmental awareness has led to more attention being given to the process of paper production and the raw materials and chemical usage. In this study, we analyzed the effect of chemical, concentration and cooking time on the characteristics of sludge and physical appearance of pulp obtained from pulping kenaf stem. The stem was pulped with 20%, 60% and 90% concentrations of formic acid and sodium hydroxide at 1 hour, 2 hours and 3 hours intervals to determine the parameters of their sludge as well as pulp appearance. The parameters considered include carbon, nitrogen, turbidity, phosphorus, ash and moisture. Sludge from sodium hydroxide pulping showed lowest value (0.02) of carbon with 60% concentration and highest (4.30) with 90% after 1hr cooking. Formic acid sludge that reported zero carbon with 20% concentration gave lowest value (1.77) at 60% after 1hr and highest value (8.73) after 3hrs with 90% concentration. Both formic acid and sodium hydroxide sludge recorded highest values (0.29 & 39.77) of nitrogen at 60% concentrations. The sludges of the two chemicals were most turbid at 90% and less at 60% concentrations with highest phosphorus values at the same concentrations. Both sludges reported lowest moisture contents at 60%. Sodium hydroxide showed highest ash at 20% after 1hr cooking while the highest value for formic acid was recorded at 90% after 3hrs cooking. The 60% formic acid at 2 hours gave a better pulp on physical examination and the sludge from the same process can also be reused.
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Stürmer, Bernhard, i Melanie Waltner. "Best Available Technology for P-Recycling from Sewage Sludge—An Overview of Sewage Sludge Composting in Austria". Recycling 6, nr 4 (17.12.2021): 82. http://dx.doi.org/10.3390/recycling6040082.
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In order to close the phosphorus cycle in the long term, efficient recycling processes are necessary to ensure that this critical nutrient can be returned to arable land. Sewage sludge recycling is of particular importance due to the relatively high phosphorus content of sewage sludge. In this article, the current recycling paths of Austrian sewage sludge are highlighted, focusing on the advantages and limitations of sewage sludge composting. In addition to nutrient contents, pollutant loads were also analyzed in order to also discuss the limitations of this recycling pathway. Therefore, data from Austrian composting plants with focus on sewage sludge are used. The results show that the currently relevant pollutants (heavy metals) are predominantly below the limits prescribed for recycling and spreading on arable land. However, in order to decide on a recycling path at an early stage, a pollutant monitoring system must be in place. Due to pollution, mono-incineration with subsequent phosphorus recovery is also currently being discussed in Austria. Mono-incineration can represent an important component of sewage sludge disposal, because some sewage sludges are not suitable for composting due to potential environmental hazards. Therefore, it is important that evidence-based limit values and measures for the reduction in pollutants for input sources are determined.
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Novak, John T., i Chang Min Park. "The effect of iron and aluminium for phosphorus removal on anaerobic digestion and organic sulfur generation". Water Science and Technology 62, nr 2 (1.07.2010): 419–26. http://dx.doi.org/10.2166/wst.2010.300.
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The addition of iron or aluminium into activated sludge basins for phosphorus removal is likely to impact both the efficiency of the anaerobic digestion process and the generation of odor-causing compounds following digestion and dewatering. In this study, the impact of iron and aluminium addition on digestion and odor-causing compounds was investigated by using batch digestion of combined primary and waste activated sludge. It was found that aluminium addition resulted in a decrease in volatile solids destruction by anaerobic digestion of approximately 2%. Of the 7 sludges tested, 5 showed a small increase in volatile solids destruction after iron addition. With regard to the generation of organic sulfur odors from the dewatered sludge cakes, both iron and aluminium reduced odor-causing gases except for one sludge that had already received iron for phosphorus control in the full-scale process. It appears that iron and aluminium addition will benefit odor control.
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Daneshgar, Saba, Armando Buttafava, Doretta Capsoni, Arianna Callegari i Andrea Capodaglio. "Impact of pH and Ionic Molar Ratios on Phosphorous Forms Precipitation and Recovery from Different Wastewater Sludges". Resources 7, nr 4 (6.11.2018): 71. http://dx.doi.org/10.3390/resources7040071.
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Phosphorus is an essential nutrient for plants, which use it as a basic fertilizer component and is expected to increase significantly in the coming years due to higher food crops demand. Unfortunately, the available phosphorus natural reserves are not renewable, and estimates indicate their rapid decline in the future. Urban wastewater, due to its abundance and relatively high phosphorus content, is an excellent candidate for phosphorus recovery, while the element’s removal from urban effluents was introduced in the 1970′s to limit the undesired effects of eutrophication. In this study, the process of struvite (and related phosphorous compounds) crystallization was investigated for three different sludge types, and the results were compared. While most studies focus strictly on anaerobically digested sludge for high struvite precipitation efficiency, this study investigated the possibility of inducing precipitation on both aerobic (extended aeration) and anaerobic sludges produced by two wastewater treatment plants in northern Italy. Analysis of precipitates from sludge samples was compared, where the focus was on the aerobic sludge, and its potential for struvite recovery. The effect of different reaction parameters was studied under different operating conditions, and the use and effects of Ca(OH)2 addition as an inexpensive potential pH adjustment reagent was investigated.
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Arrobas, Margarida, Ramily Meneses, Andressa Gribler Gusmão, Julieta Moreira da Silva, Carlos Manuel Correia i Manuel Ângelo Rodrigues. "Nitrogen-Rich Sewage Sludge Mineralized Quickly, Improving Lettuce Nutrition and Yield, with Reduced Risk of Heavy Metal Contamination of Soil and Plant Tissues". Agronomy 14, nr 5 (27.04.2024): 924. http://dx.doi.org/10.3390/agronomy14050924.
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Sewage sludge should primarily find use in agriculture, reducing the quantity directed towards alternative disposal methods like incineration or deposition in municipal landfills. This study evaluated the agronomic value and the risk of soil and plant tissue contamination with heavy metals in sewage sludge obtained from two wastewater treatment plants (WWTP). The experiment was arranged as a 2 × 5 factorial (two sewage sludges, five sanitation treatments), involving lettuce cultivation in pots over two growing cycles. The two sewage sludges were sourced from the WWTPs of Gelfa and Viana do Castelo and underwent five sanitation and stabilization treatments (40% and 20% calcium oxide, 40% and 20% calcium hydroxide, and untreated sewage sludge). The Gelfa sewage sludge, characterized by a higher initial nitrogen (N) concentration, resulted in greater dry-matter yield (DMY) (12.4 and 8.6 g plant−1 for the first and second growing cycles, respectively) compared to that from Viana do Castelo (11.0 and 8.1 g plant−1), with N release likely being a major factor influencing crop productivity. The high N concentration and the low carbon (C)/N ratio of sewage sludge led to rapid mineralization of the organic substrate, which additionally led to a higher release of other important nutrients, such as phosphorus (P) and boron (B), making them available for plant uptake. Alkalizing treatments further stimulated sewage sludge mineralization, increasing soil pH and exchangeable calcium (Ca), thereby enhancing Ca availability for plants, and indicating a preference for use in acidic soils. Cationic micronutrients were minimally affected by the sewage sludge and their treatments. The concentrations of heavy metals in the sewage sludge, soils, and lettuce tissues were all below internationally established threshold limits. This study highlighted the high fertilizing value of these sewage sludges, supplying N, P, and B to plants, while demonstrating a low risk of environmental contamination with heavy metals. Nevertheless, the safe use of sewage sludge by farmers depends on monitoring other risks, such as toxic organic compounds, which were not evaluated in this study.
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Magdalena, Jastrzębska, Kostrzewska Marta, Treder Kinga, Makowski Przemysław, Saeid Agnieszka, Jastrzębski Wiesław i Okorski Adam. "Fertiliser from sewage sludge ash instead of conventional phosphorus fertilisers?" Plant, Soil and Environment 64, No. 10 (15.10.2018): 504–11. http://dx.doi.org/10.17221/347/2018-pse.
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Recycling of phosphorus (P) from municipal waste for the use as a fertiliser can be an alternative to the non-renewable resources of this element as well as a method in the management of civilisation by-products that are a burden to the environment. An innovative phosphorus suspension fertiliser, produced on the basis of ash from incineration of sewage sludge and phosphorus solubilising bacteria Bacillus megaterium was compared in field trials with spring wheat conducted in 2014 and 2015 with superphosphate and phosphorite. The new fertiliser was not inferior to the commercial fertilisers in terms of the effect on wheat yield volumes, the uptake of P by wheat and the sanitary condition of the wheat field, especially when grown protected from weeds, pathogens and pests. It is expected that such a fertiliser can be an alternative to fertilisers produced from non-renewable resources, provided it does not deteriorate the quality of agricultural production and will be safe for the environment.
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Bruus, Jacob H., Jimmy R. Christensen i Hanne Rasmussen. "Anaerobic Storage of Activated Sludge: Effects on Conditioning and Dewatering Performance". Water Science and Technology 28, nr 1 (1.07.1993): 109–16. http://dx.doi.org/10.2166/wst.1993.0028.
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Since dewatering equipment is commonly operated only during normal working hours, activated sludge must often be stored in an anaerobic condition prior to conditioning. It is the objective of this study to investigate the influence of anaerobic storage on conditioning requirements and dewatering performance on a laboratory scale. Sludges were collected at two large treatment plants (removal of organic matter, nitrogen and phosphorus) and one small treatment plant (removal of organic matter). Thickened activated sludges from the three wastewater treatment plants were stored anaerobically in the laboratory and analyzed frequently during fourteen days of storage. Both organic and inorganic conditioning was used. Turbidity and Dissolved Organic Carbon (DOC) in the sludge bulk water increased as a result of the anaerobic storage. These parameters indicated a release of colloids, dissolved exopolymers and fermentation waste products such as fatty acids to the bulk water. These constituents consumed additional cationic polyelectrolyte. Filterability at the optimal dosage of polyelectrolyte was not affected by anaerobic storage. Therefore, polyelectrolyte requirements are governed by the bulk water constituents, whereas filterability of the sludge is determined by the degree of sludge floc conditioning. Iron requirements seemed unaffected by anaerobic storage, but lime requirements to obtain good filterability increased with anaerobic storage time.
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Jang, Gyoung Gug, Joshua A. Thompson, Pimphan Aye Meyer, Patrick Zhang, Ziheng Shen i Costas Tsouris. "Technoeconomic Assessment of Phosphoric Acid and Rare Earth Element Recovery from Phosphoric Acid Sludge". Sustainability 16, nr 16 (15.08.2024): 6984. http://dx.doi.org/10.3390/su16166984.
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Sustainability faces many challenges, including the availability of materials necessary for technological advancement. Rare earth elements (REEs), for example, are key materials for several manufacturing industries that can unlock renewable energy and sustainable development. In this study, a decanter centrifuge has been employed to successfully separated phosphoric acid and REE-containing particles from phosphoric acid sludge with concentrations ranging from 1000 to 2200 ppm REEs. Operating efficiently with up to 35 wt.% solids, the centrifuge was demonstrated to achieve approximately 95% phosphoric acid recovery and 90% REE recovery in a single pass, eliminating the need for additional processing steps. This breakthrough supports a proposed rare earth oxide (REO) recovery process integrating phosphoric acid (PA), elemental phosphorus (P4), and REO into two potential pathways: PA-REO and PA-P4-REO. These processes aim to reintroduce recovered phosphoric acid into the main product to significantly increase output and revenue. Post-separation, phosphorus-rich particles can be converted to P4, while REE-containing solids undergo further treatment including acid leaching, extraction/stripping, precipitation, and calcination to produce a marketable REO material. Technoeconomic analysis indicates promising profitability, with the PA-REO process showing a delta net present value (∆NPV) of USD 441.8 million over a 12-year period and expected return within a year of construction, while the PA-P4-REO process yields a ∆NPV of USD 178.7 million over a 12-year return period. Both pathways offer robust financial prospects and demonstrate the feasibility of commercial-scale REO recovery from phosphoric acid sludge, offering an economically feasible approach to produce REEs for future sustainable development challenges related to sustainability.
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Yuxin, Zhao, Wang Liang, Yu Helong, Jiang Baojun i Jiang Jinming. "Comparison of sludge treatment by O3 and O3/H2O2". Water Science and Technology 70, nr 1 (26.04.2014): 114–19. http://dx.doi.org/10.2166/wst.2014.185.
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This work focuses on the comparison of sludge decomposition caused by ozone (O3) alone and by ozone/hydrogen peroxide (O3/H2O2). The content of carbonaceous organic materials, nitrogenous compounds and phosphoric substances in sludge supernatant were measured. The release of soluble chemical oxygen demand, total nitrogen (TN) and total phosphorus (TP) caused by O3/H2O2 treatment were more than by O3 alone. As a result, it can be concluded that the efficiency of sludge breakup in O3/H2O2 was better than that in O3 alone. However, a peak appeared in both systems for the biodegradable substances such as carbohydrate. Carbohydrate could be used as the carbon source for denitrification, and the releasing of TN and TP may become an additional burden for a subsequent biological system. So, it was of benefit for the enhancement of cryptic growth and cost reduction by raising and maintaining the content of biodegradable substance and reducing the concentrations of the nitrogenous and phosphoric substances as far as possible. Therefore, sludge treated by O3/H2O2 with lower O3 dose would be more suitable than O3 alone.
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Bridle, T. R., i D. Pritchard. "Energy and nutrient recovery from sewage sludge via pyrolysis". Water Science and Technology 50, nr 9 (1.11.2004): 169–75. http://dx.doi.org/10.2166/wst.2004.0562.
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Energy recovery and nutrient reuse from sewage sludge has traditionally been achieved via anaerobic digestion/power generation with land application of the biosolids. By contrast, thermal processes such as pyrolysis have typically been used only for energy recovery. One such technology has demonstrated at commercial scale that all of the energy in sludge can be beneficially recovered and reused. No attempt was however made to recover and reuse sludge nutrients. There are many potential benefits of using pyrolysis for both energy and nutrient recovery. Firstly, unlike digestion, the principal energy product is oil, which can readily be stored and used when required, ensuring that energy recovery is maximised. Secondly is that the sludge nutrients are recovered in the pyrolysis char. Laboratory soil incubation studies using char from the Subiaco demonstration plant were conducted over an eight-week period to confirm nutrient availability. Results from this study showed that the phosphorus in the char is plant available although the nitrogen was insoluble. Based on these results it appears that there is potential to use pyrolysis as an effective means to recover and reuse both the energy and the very valuable phosphorus present in sewage sludges.
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Ghosh, S., i D. C. Taylor. "Kraft-Mill Biosolids Treatment by Conventional and Biphasic Fermentation". Water Science and Technology 40, nr 11-12 (1.12.1999): 169–77. http://dx.doi.org/10.2166/wst.1999.0709.
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Kraft primary and mixed primary-activated sludges were gasified by thermophilic (50 °C) high-rate and mesophilic two-phase digestion. Kraft sludges were deficient in nitrogen, phosphorus, and other unidentified nutrients. Municipal sludge proved to be a much better nutrient source than inorganic salts. Performance of the mesophilic (35°C), two-phase anaerobic digestion (TPAD) system was about the same as that of thermophilic single-stage, high-rate digestion at a 10-day HRT as judged in terms of methane yield (0.17 SCM/kg VS added) and VS reduction efficiency (43%). The mesophilic TPAD process yielded a higher methane-content (65%) fuel gas; it is capable of exhibiting higher net-energy recovery efficiency than thermophilic single-stage digestion.
34
Kuba, T., A. Wachtmeister, M. C. M. van Loosdrecht i J. J. Heijnen. "Effect of nitrate on phosphorus release in biological phosphorus removal systems". Water Science and Technology 30, nr 6 (1.09.1994): 263–69. http://dx.doi.org/10.2166/wst.1994.0277.
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The effect of nitrate on phosphorus release by biological phosphorus removing organisms has been studied. Denitrifying (DPB) or aerobic phosphorus removing bacteria were enriched in an anaerobic-anoxic or anaerobic-aerobic sequencing batch reactor (SBR). The enrichment sludges were used in batch tests, in which the effect of simultaneous presence of substrate (HAc) and nitrate was studied on the phosphorus release. It could be concluded that a reduction of the phosphorus release by nitrate in biological phosphorus removal systems is partly due to the presence of DPB, which utilize HAc for denitrification, not for phosphorus release. PHB (poly-β-hydroxybutyrate) was always produced and phosphorus was released by DPB sludge when nitrate and HAc were simultaneously present. The reducing power (NADH2) and the energy (ATP) for this process seemed to be obtained from HAc oxidation by nitrate as well as from polyphosphate degradation. After removal of the HAc, PHB degradation and phosphorus uptake occurred.
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McMahon, Katherine D., Michael A. Dojka, Norman R. Pace, David Jenkins i Jay D. Keasling. "Polyphosphate Kinase from Activated Sludge Performing Enhanced Biological Phosphorus Removal". Applied and Environmental Microbiology 68, nr 10 (październik 2002): 4971–78. http://dx.doi.org/10.1128/aem.68.10.4971-4978.2002.
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ABSTRACT A novel polyphosphate kinase (PPK) was retrieved from an uncultivated organism in activated sludge carrying out enhanced biological phosphorus removal (EBPR). Acetate-fed laboratory-scale sequencing batch reactors were used to maintain sludge with a high phosphorus content (approximately 11% of the biomass). PCR-based clone libraries of small subunit rRNA genes and fluorescent in situ hybridization (FISH) were used to verify that the sludge was enriched in Rhodocyclus-like β-Proteobacteria known to be associated with sludges carrying out EBPR. These organisms comprised approximately 80% of total bacteria in the sludge, as assessed by FISH. Degenerate PCR primers were designed to retrieve fragments of putative ppk genes from a pure culture of Rhodocyclus tenuis and from organisms in the sludge. Four novel ppk homologs were found in the sludge, and two of these (types I and II) shared a high degree of amino acid similarity with R. tenuis PPK (86 and 87% similarity, respectively). Dot blot analysis of total RNA extracted from sludge demonstrated that the Type I ppk mRNA was present, indicating that this gene is expressed during EBPR. Inverse PCR was used to obtain the full Type I sequence from sludge DNA, and a full-length PPK was cloned, overexpressed, and purified to near homogeneity. The purified PPK has a specific activity comparable to that of other PPKs, has a requirement for Mg2+, and does not appear to operate in reverse. PPK activity was found mainly in the particulate fraction of lysed sludge microorganisms.
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Nussupbekov, B. R. "ELECTROHYDRAULIC METHOD FOR PROCESSING OF THE PHOSPHORUSCONTAINING SLUDGES". Eurasian Physical Technical Journal 19, nr 1 (39) (28.03.2022): 99–104. http://dx.doi.org/10.31489/2022no1/99-104.
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The creation of an effective method for processing toxic waste from phosphorus production, as well as the suppression of the sludge formation process itself, are still relevant. This article discusses a method for processing toxic phosphorus sludge using electro hydraulic impulses. The phosphorus sludge structures before and after treatment with electric discharges are shown. The histograms of the distribution of phosphorus sludge particles by size after processing with electrohydraulic pulses are considered. It's established the content of large droplets is low and on the contrary the high content of droplets of small size in the phosphorus sludge at the electro hydraulic treatment result.
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Obarska-Pempkowiak, H., A. Tuszyńska i Z. Sobociński. "Polish experience with sewage sludge dewatering in reed systems". Water Science and Technology 48, nr 5 (1.09.2003): 111–17. http://dx.doi.org/10.2166/wst.2003.0294.
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Macrophyte plants e.g. reed, cattails, bulrush, can be applied to sewage sludge utilisation. One of the first facilities of this type in the Gdansk region (Northern Poland) was established in Darzlubie in 1995 and primary sludge has been utilised in reed beds there. The objective of the undertaken research was evaluating the influence of sewage sludge storage on its chemical and biological properties. A total of 5.5 m thick layer of primary, anaerobically stabilised sludge (moisture 90-96%) was loaded to the reed bed during 6 years of operation. As a consequence of dewatering and biochemical transformation, the sludge layer decreased to 30 cm. Moisture, organic matter, total nitrogen and total phosphorus contents, as well as coli index, Clostridium perfringens index and the number of Ascaris lumbricoides ova were measured. Also the contents of heavy metals (Cu, Pb, Zn, Ni, Cr and Cd) were determined in sludge samples. The study showed that sludge storage in reed beds results in dewatering and partial stabilisation. In the reed lagoons in Swarzewo and Zambrow, dewatering of secondary sludges was investigated. The results of measurements of the quality of sludge and effluent from the reed lagoon in Zambrow are also presented.
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Al-Thyabat, S., i P. Zhang. "REE extraction from phosphoric acid, phosphoric acid sludge, and phosphogypsum". Mineral Processing and Extractive Metallurgy 124, nr 3 (19.01.2015): 143–50. http://dx.doi.org/10.1179/1743285515y.0000000002.
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Kindzierski, Warren B., i Steve E. Hrudey. "Effects of phosphorus removal chemicals upon methane production during anaerobic sludge digestion". Canadian Journal of Civil Engineering 13, nr 1 (1.02.1986): 33–38. http://dx.doi.org/10.1139/l86-005.
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Aluminum sulphate (alum) and ferric chloride are commonly employed to aid phosphorus removal in wastewater treatment. Previous studies have indicated that these chemical coagulants produce sludges that adversely affect anaerobic digestion. The objective of this study was to assess the magnitude of the effects chemical coagulants have upon methane generation in anaerobic digestion. Methane production was monitored and concentrations of aluminum or iron present during batch digestion of chemically precipitated sludge were measured.Both alum and ferric chloride addition to activated sludge produced a sludge that demonstrated reduced methane production in batch anaerobic digestion. Neither metal inhibited methanogenesis of an acetate supplement, suggesting that chemical toxicity was not a likely explanation for overall reductions in methane formation. Considering the experimental results and the findings of others, reduced methane generation is most likely caused by physical isolation of degradable substrate by the coagulant floc, which causes an overall reduction in conversion of sludge volatile solids to methane.
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Alvarenga, Emilio, Anne Falk Øgaard i Lasse Vråle. "Effect of anaerobic digestion and liming on plant availability of phosphorus in iron- and aluminium-precipitated sewage sludge from primary wastewater treatment plants". Water Science and Technology 75, nr 7 (27.01.2017): 1743–52. http://dx.doi.org/10.2166/wst.2017.056.
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More efficient plant utilisation of the phosphorus (P) in sewage sludge is required because rock phosphate is a limited resource. To meet environmental legislation thresholds for P removal from wastewater (WW), primary treatment with iron (Fe) or aluminium (Al) coagulants is effective. There is also a growing trend for WW treatment plants (WWTPs) to be coupled to a biogas process, in order to co-generate energy. The sludge produced, when stabilised, is used as a soil amendment in many countries. This study examined the effects of anaerobic digestion (AD), with or without liming as a post-treatment, on P release from Fe- and Al-precipitated sludges originating from primary WWTPs. Plant uptake of P from Fe- and Al-precipitated sludge after lime treatment but without AD was also compared. Chemical characterisation with sequential extraction of P and a greenhouse experiment with barley (Hordeum vulgare) were performed to assess the treatment effects on plant-available P. Liming increased the P-labile fraction in all cases. Plant P uptake increased from 18.5 mg pot−1 to 53 mg P pot−1 with liming of Fe-precipitated sludge and to 35 mg P pot−1 with liming of the digestate, while it increased from 18.7 mg pot−1 to 39 and 29 mg P pot−1 for the Al-precipitated substrate and digestate, respectively. Thus, liming of untreated Fe-precipitated sludge and its digestate resulted in higher P uptake than liming its Al-precipitated counterparts. AD had a negative impact on P mobility for both sludges.
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Dong, Qirong, Martha Dagnew, Jeff Cumin i Wayne Parker. "Preliminary evaluation of biosolids characteristics for anaerobic membrane reactors treating municipal wastewaters". Water Science and Technology 72, nr 8 (13.07.2015): 1446–54. http://dx.doi.org/10.2166/wst.2015.356.
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This study assessed the characteristics of biosolids of a pilot-scale anaerobic membrane bioreactor (AnMBR) treating municipal wastewater. The production of total solids (TS) and volatile solids (VS) was comparable to that reported for the extended aeration system at solids residence time (SRT) longer than 40 days. The yields of TS and VS were reduced as SRT increased from 40 to 100 days and increased with the addition of 26 mg/L of FeCl3. The AnMBR destroyed 60–82% of the VS loading in feed wastewater and hence it was concluded the biosolids met the requirements for vector attraction reduction for land application. The concentrations of volatile suspended solids and total suspended solids in the sludge were less than those reported after anaerobic digestion of conventional primary and secondary sludge mixtures, and hence dewatering of the waste stream may be required for some applications. The nutrient content in terms of total Kjeldahl nitrogen and total phosphorus was similar to that of anaerobically digested municipal sludges. The dewaterability of the biosolids was poorer than that reported for sludges from aerobic treatment and anaerobically digested sludges. Dewaterability was improved by addition of FeCl3 and reduced SRT. The biosolids met standards for land application with regards to the concentration of heavy metals but would need further treatment to meet Class B pathogen indicator criteria.
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Watanabe, Y., i K. Kimura. "Hybrid membrane bioreactor for water recycling and phosphorus recovery". Water Science and Technology 53, nr 7 (1.03.2006): 17–24. http://dx.doi.org/10.2166/wst.2006.203.
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This paper deals with the performance of hybrid membrane bioreactor (MBR) combining the precoagulation/sedimentation and membrane bioreactor. The hybrid MBR not only produces the treated water with excellent permeate quality but also shows much lower membrane fouling than the conventional MBR. It may come from its extremely low F/M ratio to maintain the low viscosity even in the high MLSS concentration range of about 20,000 mg/L. Some results of microbial community analysis in MBRs was conducted to demonstrate the other reason for its lower membrane fouling. Hybrid MBR has a high potential to be used for the recycling use of the municipal wastewater. Coagulated sludge produced in the hybrid MBR is a promising phosphorus resource. This paper also contains a recent progress of phosphorus recovery technology, which uses a new phosphoric acids absorbent, i.e. the hexagonal mesostructured zirconium sulfate (ZS). The ZS has the extremely high adsorption capacity of phosphoric acids through anion exchange. The adsorbed phosphoric acids are released from the ZS in a high pH range of about 13.
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Bessarabov, Arkadiy, Tatyana Zakolodina, Roman Sandu i Gennady Zaikov. "CALS-Technologies in Synthesis of Multiassortmental Manufacturing for Phosphoric Sludge Utilization". Chemistry & Chemical Technology 3, nr 4 (15.12.2009): 327–33. http://dx.doi.org/10.23939/chcht03.04.327.
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CALS-projects of sodium phosphite and hypophosphite technologies – products of phosphoric sludge utilization (one of the main wastes of phosphoric industry) were developed. CALS-technology of the flexible two-grocery production was developed based on the theory of the flexible scheme synthesis.
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Kowalski, Zygmunt, i Kinga Krupa-Żuczek. "A model of the meat waste management". Polish Journal of Chemical Technology 9, nr 4 (1.12.2007): 91–97. http://dx.doi.org/10.2478/v10026-007-0098-4.
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A model of the meat waste management The European Union produces about 18 million tons of waste from meat industry per year. The real danger of the BSE disease caused a necessity of looking for a new alternative solution of meat waste management. The proposed solution of meat industry waste management would create meat production waste free with the use of the cleaner production method. Cleaner production includes: pollution prevention, reduction of the source, recovery of materials and energy (for example: the recovery of blood plasma and protein hydrolisate from bone sludge) and their recycling. The thermal processing of meat industrial waste (bone sludge, meat-bone meal and odour) is anticipated, too. Ashes from meat calcining have the phosphorus content close to its concentration, of the typical phosphoric raw materials. That confirmed the possibility of using such ashes as the substitute of phosphoric raw materials. The target model of waste free meat waste management included the results of the implemented and current research.
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Touzani, Abdelaziz, Yahya El Hammoudani, Khadija Haboubi, Lahcen Benaabidate, Iliass Achoukhi, Mohamed Moudou, Mustapha El Boudammoussi, Hatim Faiz i Fouad Dimane. "Characterization of sludge from the Fez wastewater treatment plant". BIO Web of Conferences 109 (2024): 01015. http://dx.doi.org/10.1051/bioconf/202410901015.
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The Fès wastewater treatment plant is of the activated sludge type. It has been in service since 2014, and receives 155,400 cubic meters per day of domestic wastewater from numerous urban and rural communities: Fès, Ras El Ma, Oulad Tayeb and Ain Chkef. On the one hand, this WWTP generates clean, purified water which is discharged into the receiving environment without any harm to the environment, and on the other, it produces huge quantities of residual sludge, i.e. 5,100 t/year. The aim of this study is to characterize the sludge from the Fez wastewater treatment plant, following sludge treatability tests by monitoring the various analytical parameters. To be able to choose the right technique for the type of sludge to be treated. In our case, for sludge from the Fez wastewater treatment plant, physico-chemical characteristics were carried out for COD, BOD5, TSS, total nitrogen and phosphorus, showing the sludge’s richness in nutrients. The characterization of the sludge from the Fez wastewater treatment plant showed the potential of this product to be valorized.
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Temirov, Uktam, Nodir Doniyarov, Bakhrom Jurakulov, Najimuddin Usanbaev, Ilkhom Tagayev i Abdurasul Mamataliyev. "Obtaining complex fertilizers based on low-grade phosphorites". E3S Web of Conferences 264 (2021): 04009. http://dx.doi.org/10.1051/e3sconf/202126404009.
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In the study, the process preparation of phosphorus-humus fertilizers based on low-grade Central Kizilkum phosphorites activated using sulfuric acid in the ratio of 30-70% for decomposition of CaCO3 in the phosphorite followed by addition of activated sludge from municipal waster water was investigated.
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Huang, Xiaofeng, Yanfu Wei, Tao Zhou, Yangsong Qin, Kunyang Gao i Xinyue Ding. "Synthesis of tetrakis (hydroxymethyl) phosphonium chloride by high-concentration phosphine in industrial off-gas". Water Science and Technology 68, nr 2 (1.07.2013): 342–47. http://dx.doi.org/10.2166/wst.2013.240.
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With increasing consumption of phosphate rock and acceleration of global phosphate production, the shortage of phosphate resources is increasing with the development and utilization of phosphate. China's Ministry of Land and Resources has classified phosphate as a mineral that cannot meet China's growing demand for phosphate rock in 2010. The phosphorus chemical industry is one of the important economic pillars for Yunnan province. Yellow phosphorus production in enterprises has led to a significant increase in the amount of phosphorus sludge. This paper focuses on phosphine generation in the process of phosphoric sludge utilization, where the flame retardant tetrakis (hydroxymethyl) phosphonium chloride (THPC) is synthesized by high concentrations of phosphine. The optimum conditions are determined at a space velocity of 150 h−1, a reaction temperature of 60 °C, 0.75 g of catalyst, and a ratio of raw materials of 4:1. Because of the catalytic oxidation of copper chloride (CuCl2), the synthesis of THPC was accelerated significantly. In conclusion, THPC can be efficiently synthesized under optimal conditions and with CuCl2 as a catalyst.
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Pesonen, Janne, Pekka Myllymäki, Sari Tuomikoski, Gwen Vervecken, Tao Hu, Hanna Prokkola, Pekka Tynjälä i Ulla Lassi. "Use of Calcined Dolomite as Chemical Precipitant in the Simultaneous Removal of Ammonium and Phosphate from Synthetic Wastewater and from Agricultural Sludge". ChemEngineering 3, nr 2 (18.04.2019): 40. http://dx.doi.org/10.3390/chemengineering3020040.
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Phosphorus as phosphate and nitrogen as ammonium or nitrate are the main nutrients in wastewaters and agricultural sludges. They runoff easily to waterways and cause eutrophication in water bodies. However, ammonium and phosphate could be precipitated simultaneously and used as recycled nutrients. In this research, dolomite calcined at 650 °C, 750 °C, or 950 °C and commercial MgO were used as precipitants in simultaneous phosphate and ammonium removal from synthetic (NH4)2HPO4 solution and agricultural sludge. Calcination at 750 °C was the preferred option as dolomite was decomposed to MgO and CaCO3 for optimal struvite precipitation. Molar ratios of 1.1–1.6:1–2:2 (Mg:P:N) were employed in the experiments. Very robust ammonium removal was obtained with MgO (57%), dolomite 650 °C and dolomite 750 °C (75%). MgO removed almost all phosphate, while dolomite 650 °C removed 65%, and dolomite 750 °C removed 60% (70% from agricultural sludge). Some part of the phosphate was adsorbed, most likely by CaCO3, during dolomite precipitation. Struvite was the only identified reaction product in all samples after 24 h of precipitation. Calcined dolomite had great potential in ammonium and phosphate precipitation from both synthetic waters and agricultural sludges and the precipitates could be used as recycled fertilizers.
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Rossi, Laura, Sini Reuna, Tommi Fred i Mari Heinonen. "RAVITA Technology – new innovation for combined phosphorus and nitrogen recovery". Water Science and Technology 78, nr 12 (29.12.2018): 2511–17. http://dx.doi.org/10.2166/wst.2019.011.
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Abstract Present phosphorus (P) recovery technologies mainly contain P recovery from sludge liquor or ash. These types of technologies are suitable for large wastewater treatment plants (WWTPs) with enhanced biological phosphorus removal (EBPR), digestion and/or incineration. In Finland and other Nordic countries, strict P discharge limits require chemical precipitation, thus EBPR alone is not sufficient. Ammonium recovery from wastewater, on the other hand, is not so often discussed. However, recovery from WWTP reject waters would decrease the energy demand of ammonium synthesis by Haber-Bosh technology and the energy demand of the WWTP's biological process. Helsinki Region Environmental Services Authority (HSY) has developed a new process called RAVITA whereby P and nitrogen recovery are combined in order to produce phosphoric acid (H3PO4) and ammonium phosphate (NH4)3PO4. Furthermore, in this process metal salt used in precipitation is recovered. The research was carried out on pilot (1,000 population equivalent) and laboratory scales. The objectives of this article are to explain the principles of the RAVITA process and give the first results of processing and production of chemical sludge.
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Bond, Philip L., Jürg Keller i Linda L. Blackall. "Characterisation of enhanced biological phosphorus removal activated sludges with dissimilar phosphorus removal performances". Water Science and Technology 37, nr 4-5 (1.02.1998): 567–71. http://dx.doi.org/10.2166/wst.1998.0719.
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A sequencing batch reactor (SBR) was operated for enhanced biological phosphorus removal (EBPR) and dramatic differences in the P removing capabilities were obtained in different stages of the operation. At one stage extremely poor P removal occurred and it appeared that bacteria inhibiting P removal overwhelmed the reactor performance. Changes were made to the reactor operation and these led to the development of a sludge with high P removing capability. This latter sludge was analysed by fluorescent in situ hybridisation (FISH) using a probe specific for Acinetobacter. Very few cells were detected with this probe indicating that Acinetobacter played an insignificant role in the P removal occurring here. Analysis of the chemical transformations of three sludges supported the biochemical pathways proposed for EBPR and non-EBPR systems in biological models. A change in operation that led to the improved P removal performance included permitting the pH to rise in the anaerobic periods of the SBR cycle.