Phosphorus Elimination Research Articles

Phosphorus elimination from aqueous solution using ‘zirconium loaded okara’ as a biosorbent

This work deals with the capture of phosphorus from aqueous solutions by biosorption onto zirconium loaded okara (ZLO). The batch-mode experiments were conducted to examine the effect of pH, biosorbent dose, initial phosphorus concentration, contact time, and temperature on the process. It was found that, the adsorption was most favored in the pH range of 2–6. The optimal doses for the adsorption, at initial phosphorus concentrations of 5, 10, 25, 50mg/L were 2, 3, 7, 10g/L, respectively. The maximum adsorption capacity of ZLO was approximately 44.13mg PO4/g at 298K. The phosphate removal was rapid, reaching 95% in 30min. Freundlich model best fitted the equilibrium data, while Pseudo-second order model satisfactorily described the kinetic results. Thermodynamic analysis revealed feasible, spontaneous, and endothermic nature of the process. The research would be beneficial for developing a promising, eco-friendly phosphorus biosorbent from a plentiful AWB – okara.

Vacuum Refining of Molten Silicon

AbstractMetallurgical fundamentals for vacuum refining of molten silicon and the behavior of different impurities in this process are studied. A novel mass transfer model for the removal of volatile impurities from silicon in vacuum induction refining is developed. The boundary conditions for vacuum refining system—the equilibrium partial pressures of the dissolved elements and their actual partial pressures under vacuum—are determined through thermodynamic and kinetic approaches. It is indicated that the vacuum removal kinetics of the impurities is different, and it is controlled by one, two, or all the three subsequent reaction mechanisms—mass transfer in a melt boundary layer, chemical evaporation on the melt surface, and mass transfer in the gas phase. Vacuum refining experimental results of this study and literature data are used to study the model validation. The model provides reliable results and shows correlation with the experimental data for many volatile elements. Kinetics of phosphorus removal, which is an important impurity in the production of solar grade silicon, is properly predicted by the model, and it is observed that phosphorus elimination from silicon is significantly increased with increasing process temperature.

Seeking a compromise between pharmaceutical pollution and phosphorus load: Management strategies for Lake Tegel, Berlin

Lake Tegel (Berlin, Germany) is controlled by two main inflows: inflow #1 (River Havel) is heavily phosphorus-laden, whereas inflow #2 is an artificial confluence that includes discharge from a municipal wastewater treatment plant distinguished by high levels of phosphorus and pharmaceuticals. To reduce the phosphorus load on the lake, a phosphorus elimination plant (PEP) is situated at inflow #2. Moreover, the two inflows are short-circuited by a pipeline that transfers part of the inflow #1 water to the PEP and finally releases it into inflow #2. The pipeline and the PEP have contributed to a continuous reduction in the total phosphorus concentration of Lake Tegel in the past 25 years. We investigate the question of whether the existing lake pipeline can also be used to reduce the amount of pharmaceuticals in Lake Tegel originating from inflow #2 by dilution with water from River Havel, by diverting part of inflow #2 around the lake, or by a combination of both strategies. The circulation pattern of Lake Tegel is complicated by complex bathymetry and numerous islands and is therefore highly sensitive to winds. We tested seven different management scenarios by hydrodynamic modeling for a period of 16 years with the two-dimensional version of the Princeton Ocean Model (POM). None of the scenarios provided a strategy optimal for both pharmaceuticals and phosphorus. Nonetheless, compound regimes, such as alternating the pipe flow direction or adding another pipeline, allowed the most abundant pharmaceutical (carbamazepine) to be reduced while maintaining the current phosphorus level. This study demonstrates the ability of immediate lake regulation measures to maintain water quality. In the case of Lake Tegel, the pipeline can be fully effective with regard to pharmaceuticals only in combination with additional efforts such as advanced pharmaceutical treatment of wastewater and/or phosphorus reduction in the River Havel catchment.

Performance of a MBR for the treatment of blackwater

The paper describes the experience gained in operating a membrane bioreactor (MBR) for the treatment of blackwater. Beside a complete characterization of blackwater, operational conditions and removal efficiency concerning parameters such as COD, BOD(5), nitrogen and phosphorus as well as microbiological parameters were determined. Furthermore the membrane performance was investigated. The results show that in blackwater treatment nitrogen removal is limited in the biological process, because of the blackwater matrix (BOD(5):TKN=1.1:1.0). Blackwater contains a high fraction of soluble, inert COD, which is not degradable by biological operation, only. Phosphorus elimination was negligible, probably induced by precipitation of cellular phosphorus. Although the released permeate was free of the fecal indicators E. coli and streptococcus and met guideline values, a direct reuse as service water is not recommended due to the yellowish coloration.

Phosphorus Additives in Food and their Effect in Dialysis Patients

There is substantial epidemiologic evidence linking hyperphosphatemia and cardiovascular and all-cause mortality among dialysis patients (1,2). Therefore, control of hyperphosphatemia is a crucial element of the routine clinical care of dialysis patients. Theoretically, control of serum phosphorus levels can be achieved by the right combination of decreased dietary phosphorus intake, decreased GI phosphorus absorption by phosphate binders, and increased phosphorus elimination via dialysis. However, the clinical reality is that despite the widespread use of high-efficiency dialyzers, new phosphorus binders, and usual nutritional education, the average serum phosphorus in dialysis patients remains higher than the levels recommended by practice guidelines, except in patients on long nocturnal hemodialysis (3). The lack of attention by practicing nephrologists to dietary phosphorus restriction in general, and more specifically the lack of awareness regarding the increasing consumption of processed foods rich in phosphate additives, may significantly contribute to limit the efficacy of the current interventions (4). Estimation of the dietary intake of phosphorus should consider not only phosphorus contained in natural food, but also phosphorus added in processing food. In general, foods high in protein like meats, milk, eggs, and cereals are also naturally high in phosphorus and traditionally have represented the main source of dietary phosphorus (5). However, this is changing as phosphates are currently being added to a large and increasing number of processed foods, including meats, cheeses, dressings, beverages, and bakery products (6–8). As a result, and depending on the food choices, such additives may increase the phosphorus intake by as much as 1.0 g/d (7). Phosphorus in additives is more readily absorbed than that from foods naturally high in phosphorus; as a result, additives will have a greater effect on hyperphosphatemia than an equivalent amount of naturally …

Phosphorus elimination of reclaimed water by different kinds of constructed wetlands

Because of water shortage in Beijing, most ponds and moats there have not enough water. In some times of each year, there is even no water. Therefore, wastewater reclamation and reuse has been paid more and more attention. Reclaimed water used as scenic water such as to supplement city moats, lakes etc. is considered. In this paper, some experiments were done to investigate whether constructed wetlands can reduce the nitrogen and phosphorus concentration further in order to avoid the eutrophication of water bodies through use of reclaimed water for scenic environment. As we know, phosphorus is an important factor to cause algae bloom directly in water bodies. So investigation on phosphorus elimination is a key object for this study, which is composed of two main parts. The first part is laboratory scale testing to select the appropriate substrates of constructed wetlands among some materials. The second part is pilot scale experiments to find out optimal operational condition of different kinds of constructed wetlands. Based on the lab tests, we found that foamy-brick could provide a good condition for plants and microorganisms. According to the pilot scale experiments, it could be concluded that under optimal operational conditions, horizontal flow wetlands could work well. The results of the experiments also showed that integrated vertical flow wetlands are not suitable for phosphorus elimination of reclaimed water.

Strategy and current status of combating eutrophication in two Berlin lakes for safeguarding drinking water resources

After reduction of the external phosphorus load by phosphorus elimination plants, Lake Tegel and Schlachtensee in Berlin underwent a significant trophic improvement. The phosphorus elimination plants work by precipitation/coagulation/flocculation--sedimentation--post precipitation--filtration. The external load was reduced by one to two orders of magnitude down to 10-20 mgg PL(-1). The inlake phosphorus concentration followed. The development of algae and cyanobacteria was reduced substantially below a threshold value of about 50 microg PL(-1) clearly due to phosphorus limitation. In Lake Tegel, the external load reduction of the main inflow was counteracted partially by the external load of the second main inflow by the River Havel and the internal load. This has to be managed further in future.

Phosphorus Removal Characteristics in Hydroxyapatite Crystallization Using Converter Slag

This study was performed to investigate the phosphorus removal characteristics in hydroxyapatite (HAP) crystallization using converter slag as a seed crystal and the usefulness of a slag column reactor system. The effects of alkalinity, and the isomorphic-substitutable presence of ionic magnesium, fluoride, and iron on HAP crystallization seeded with converter slag, were examined using a batch reactor system. The phosphorus removal efficiencies of the batch reactor system were found to increase with increases in the iron and fluoride ion concentrations, and to decrease with increases in the alkalinity and magnesium ion concentration. A column reactor system for HAP crystallization using converter slag was found to achieve high, stable levels of phosphorus elimination: the average PO4-P removal efficiency over 414 days of operation was 90.4%, in which the effluent phosphorus concentration was maintained at less than 0.5 mg/L under the appropriate phosphorus crystallization conditions. The X-ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) spectra of the crystalline material deposited on the seed particles exhibited peaks consistent with HAP. Scanning electron micrograph (SEM) images showed that finely distributed crystalline material was formed on the surfaces of the seed particles. Energy dispersive X-ray spectroscopy (EDS) mapping analysis revealed that the molar Ca/P composition ratio of the crystalline material was 1.72.

Effects of a 250-mL enema containing sodium phosphate on electrolyte concentrations in healthy volunteers: An open-label, randomized, controlled, two-period, crossover clinical trial

Background: Enemas are used by individuals with constipation and are often required before certain medical diagnostic procedures and surgical interventions. However, abnormalities in serum electrolyte concentrations have been associated with enema use. Objective: The aim of this study was to determine the changes in serum electrolyte concentrations (phosphorus, calcium, sodium, and potassium) and urinary phosphorus elimination after the administration of a sodium phosphate enema. Methods: Healthy volunteers aged 35 to 70 years were eligible for this open-label, randomized, controlled, 2-period, crossover clinical trial at the Clinical Research Unit of the University Hospital of Navarra, Pamplona, Spain. The study comprised 2 one-day periods separated by a 7-day washout. All subjects were randomly assigned in a 1:1 ratio to 1 of 2 study sequences: (1) a single dose of Enema Casen® 250 mL in the first period followed by no treatment (control) in the second period, or (2) no treatment in the first period followed by a single dose of the study drug in the second period. The sequence of treatment was assigned using a randomization table that was prepared before the beginning of the study. Serum concentrations of phosphorus, sodium, potassium, and calcium were measured in both periods. Urinary phosphorus elimination was measured for 12 hours after enema administration (Ae 0–12) in a subset of the subjects in the second period. Adverse events (AEs) were monitored by the investigators throughout the study. Normal ranges for the electrolytes were as follows: phosphorus, 2.5 to 5 mg/dL; calcium, 8.5 to 10.5 mg/dL; sodium, 135 to 145 mEq/L; and potassium, 3.5 to 5 mEq/L. Results: Twenty-four subjects (12 men, 12 women; mean [SD] age, 47.8 [9.6] years [range, 36–68 years]) participated in the study. All of the subjects were white and none were smokers. Twelve hours after enema administration, mean serum phosphorus and sodium concentrations increased by a mean of 1.18 mg/dL and 1.32 mEq/L, respectively (both, P < 0.001). Mean serum phosphorus concentrations were above the upper limit of normal (5 mg/dL) at 30 and 60 minutes after enema administration. In all subjects the values returned to normal within 4 hours after enema administration; a meal was provided after a 3-hour fast. Four subjects (16.7%) had ≥1 serum phosphorus concentration measurement ≥7 mg/dL, a value that is considered serious hyperphosphatemia. A statistically significant correlation was found between phosphorus C max and enema retention time ( r 2 = 0.452; P < 0.001). No abnormal serum concentrations were obtained for the other electrolytes measured. Phosphorus Ae 0–12 was increased after enema administration by 86% ( P < 0.001). No serious AEs were observed, although 13 AEs were reported in 9 subjects. None of the changes in serum electrolyte concentrations were associated with clinical symptoms. Conclusions: Administration of an enema containing 250 mL of sodium phosphate was associated with serum phosphorus concentrations of ≥7 mg/dL in 16.7% of the healthy subjects who participated in the study; however, none of those subjects experienced hypocalcemia. Enema retention time was significantly correlated with the degree of phosphatemia.

Effects of nitrate on phosphorus release: comparison of two Berlin lakes

AbstractAfter installation of phosphorus elimination plants at the inflows of the eutrophic Lake Tegel and Schlachtensee, phosphorus (P) loading declined by a factor of 40 and 100, respectively. This resulted in a pronounced reduction of phosphorus concentrations in the lake water, followed by a decline of chlorophyll‐a concentrations. However, for many years P release from sediments due to mineralization and desorption of sedimentary P continued. In Schlachtensee, the presence of nitrate above the sediment suppresses P release, because the Fe/P ratio is sufficient to provide enough aerobic sorption capacity. In Lake Tegel, some P release occurs even under aerobic conditions because of the low aerobic P sorption capacity of the sediments. There, nitrate could moderate the P release peaks which occur when the Fe‐P cycle at the sediment water interface is disturbed by precipitation of iron sulfide after reduction of sulfate during times of high mineralization intensity. The potentially mobile P pool in the sediments of both lakes is rather small, indicating that the P release could subside after sufficient reduction of the external P load in Lake Tegel and the disruption of the internal P cycle in Schlachtensee.

Phosphate Elimination and Recovery From by Active Filtration Using Crushed Gas Concrete

Laboratory long-term upstream fixed-bed experiments were carried out to investigate the efficiency of phosphorus elimination with the effluent of a biological sewage treatment plant using crushed gas concrete. The development of the pHvalue in the column outflow as well as the reaction kinetics was investigated. Furthermore, the phosphorus yield was balanced for phosphorus recovery and the calcium phosphate compounds generated were specified by mineralogical analysis methods. These activities were followed by a study with respect to the suitability of the material as raw material for the phosphate industry.

Treatment of hyperphosphatemia in patients with chronic kidney disease on maintenance hemodialysis: Results of the CARE study

Most patients with end-stage renal disease develop hyperphosphatemia because their dietary intake exceeds phosphorus elimination by intermittent thrice-weekly dialysis. Inadequately treated hyperphosphatemia plays a central role in the pathogenesis of secondary hyperparathyroidism and extraosseous calcification. Moreover, in the last 15 years, this biochemical abnormality has become increasingly important following the publication of two epidemiologic studies that demonstrated an association between elevated serum phosphorus and increased mortality risk in patients with end-stage renal disease. As a result, the National Kidney Foundation Kidney Disease Outcome and Quality Initiative (K/DOQI) Bone Metabolism and Chronic Kidney Disease Guidelines recommend that serum phosphorus levels be maintained between 3.5 and 5.5 mg/dL. Unfortunately, cross-sectional studies have shown a mean serum phosphorus of 6.2 mg/dL in the maintenance hemodialysis population in the United States. An alarming 60% of patients have serum phosphorus in excess of the 5.5 mg/dL level recommended by K/DOQI guidelines. In order to achieve this new target for serum phosphorus, the most efficacious and cost-effective phosphate binders currently available should be utilized. In this review, we discuss the results of the Calcium Acetate Renagel Evaluation (CARE study), which clearly demonstrated the superiority of calcium acetate over sevelamer hydrochloride for controlling serum phosphorus and calcium-phosphate product to the levels recommended by the K/DOQI guidelines.

Optimal Control of Phosphatemia by Short Daily Hemodialysis

Hyperphosphatemia is a major risk factor in maintenance of hemodialysis patients, not only in the pathogenesis of secondary hyperparathyroidism but also in the progressive calcic vascular disease. Phosphorus is present in all nutrients rich in proteins and we can’t remove completely phosphorus intake by diet restriction or phosphate binders. Better nutritional status with higher protein intake appears with short daily hemodialysis (SDHD). Does SDHD allow a better phosphorus elimination than SHD? Ten patients mean age 52.3 ± 6.4 yrs treated on standard hemodialysis (SHD) from 11.2 ± 4.3 yrs 4 to 5 h × 3/week were switched to SDHD 2 to 2.5 h × 6/week. We have compared in the same patient phosphatemia (P), weekly phosphates removal (WPR), daily phosphates intake (DPI), and phosphates binders in SHD and in SDHD at the third month (SDHD1) and at long term (SDHD2). Results were expressed as mean ± SD and statistical analysis between SHD and SDHD were studied using Students paired t-test. SHD SDHD1 SDHD2 P (mmol/l) 2.3 ± 0.7 1.9 ± 0.5** 1.8 ± 0.4** WPR (mmol) 99.8 ± 20.8 113.5 ± 25.8* 128.2 ± 45.8* DPI (mg) 968 ± 192 1149 ± 223** 1535 ± 701* P binders +++ ++ ++ * p < 0.05 ** p < 0.001 P was significantly lower in SDHD despite a reduction in phosphates binders and high phosphates intake with better nutritional status as seen usually with SDHD. There were no significant differences between either P and DPI in the two periods on SDHD. We have confirmed these results by kinetics studies showing that 60% of phosphate elimination take place mainly during the first 2 h of dialysis sessions; so the overall WPR is higher with SDHD. We conclude that increased sessions frequency increases phosphates elimination and decreases the risk of hyperphosphatemia.

Phosphorus reduction in a shallow hypereutrophic reservoir by in-lake dosage of ferrous iron

In Bautzen Reservoir (Germany), a technique of internally dosing iron compounds in combination with a local water column destratification was developed in order to control Microcystis blooms. In this paper, experimental results concerning the phosphorus (P) precipitation by iron application are reported. First, preliminary studies were conducted serving the choice of an appropriate precipitant. Subsequently, a whole-lake experiment was carried out. Fe 2+ salts displayed a delayed oxidation and flocculation behaviour when injected into an ascending water jet. Nevertheless, the efficiency of soluble reactive phosphorus (SRP) elimination was equal to experiments with Fe 3+ compounds both in laboratory and field experiments. During Fe 2+ application, a large P-binding potential remained during the horizontal spreading of the treated water, since the proportion of the dissolved iron fraction near the dosage point was still high. Thus, measurements at a greater distance from the dosage point revealed higher amounts of P eliminated by Fe 2+ than by Fe 3+ dosage. Compared to the preceding year 1995, during the treatment periods in May–August 1996 and 1997 the SRP contents in the whole water body dropped by 72% and 54%, respectively, while the total phosphorus contents dropped by 45% at each period. We conclude that in-lake dosage of Fe 2+ is an appropriate method to reduce the P loading of hypereutrophic reservoirs.

Characterisation of phosphorus in sediments from waste stabilization ponds

The waste stabilization pond (WSP) systems are useful for the treatment of wastewater. Despite a good knowledge of these systems, the dynamics of phosphorus elimination in these systems are not well known, especially concerning the forms of phosphorus in the sediment. Phosphorus dynamics were studied with data collected from the three stabilization ponds of the Mèze (France) system. A conceptual model based on theoretical considerations was developed, and applied to each pond. The percentage of observed variation described by these models ranged between 46.2% and 74.1%. The results showed that the principal variables affecting orthophosphate in WSP systems were phosphorus input and particulate phosphorus. When the model was applied to high rate algal pond (HRAP) data, the role of photosynthesis on pH increase and P precipitation was clear. Sediments sampled in the three facultative ponds were characterised with a fractionation scheme, currently used for sediments of natural aquatic ecosystems. Inorganic phosphorus accounted for 92-94% of total sediment phosphorus, with 57–59% bound to iron hydroxides and 33–37% bound to calcium. Surprisingly, organic phosphorus represented only between 6 and 8%. Polyphosphate was detected. Phosphorus concentration was greatest in the sediment from the third pond, where an aerobic layer at the sediment surface prevented phosphorus release.

Acidification of primary sludge to promote increased biological phosphorus elimination and denitrification

The acidification of primary sludge is an important measure to promote increased biological P elimination and denitrification at wastewater treatment plants. In laboratory experiments and at large-scale plants it has been found that the COD in the influent of biological treatment stages can be increased by 10–15% in the form of easily degradable carbonic acids. However, the operation of acidification thickeners leads to odour problems, as well as to considerable problems in terms of safety, in covered tanks.

Elimination of enteroviruses, other enteric viruses, F-specific coliphages, somatic coliphages and E. coli in four sewage treatment plants of southern Germany

Research Article| May 01 2000 Elimination of enteroviruses, other enteric viruses, F-specific coliphages, somatic coliphages and E. coli in four sewage treatment plants of southern Germany Jens Fleischer; Jens Fleischer 1Landesgesundheitsamt Baden-Württemberg, Wiederholdstr. 13, Infektiologie, D-70174 Stuttgart, Germany Search for other works by this author on: This Site PubMed Google Scholar Karin Schlafmann; Karin Schlafmann 2Universitätsklinikum Tübingen, Hygiene-Institut, Abt. für Allgemeine Hygiene und Umwelthygiene, Wilhelmstr. 31, D-72074 Tübingen, Germany Search for other works by this author on: This Site PubMed Google Scholar Rowland Otchwemah; Rowland Otchwemah 2Universitätsklinikum Tübingen, Hygiene-Institut, Abt. für Allgemeine Hygiene und Umwelthygiene, Wilhelmstr. 31, D-72074 Tübingen, Germany Search for other works by this author on: This Site PubMed Google Scholar Konrad Botzenhart Konrad Botzenhart 2Universitätsklinikum Tübingen, Hygiene-Institut, Abt. für Allgemeine Hygiene und Umwelthygiene, Wilhelmstr. 31, D-72074 Tübingen, Germany Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2000) 49 (3): 127–138. https://doi.org/10.2166/aqua.2000.0011 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Twitter LinkedIn Tools Icon Tools Cite Icon Cite Permissions Search Site Search nav search search input Search input auto suggest search filter All ContentAll JournalsThis Journal Search Advanced Search Citation Jens Fleischer, Karin Schlafmann, Rowland Otchwemah, Konrad Botzenhart; Elimination of enteroviruses, other enteric viruses, F-specific coliphages, somatic coliphages and E. coli in four sewage treatment plants of southern Germany. Journal of Water Supply: Research and Technology-Aqua 1 May 2000; 49 (3): 127–138. doi: https://doi.org/10.2166/aqua.2000.0011 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex The reduction processes at four advanced sewage treatment plants in Baden-Württemberg were evaluated with regard to virus elimination and the elimination of indicator organisms from wastewater. The results of virus elimination were compared with the reduction of somatic and male specific bacteriophages and of E. coli. In total, 222 water samples were examined. The results obtained for the different treatment plants show reduction rates from 80.0% to 99.9% for enteroviruses, enumerated as PFU l−1 on BGM cell line, and reduction rates from 59.4% to 99.9% for other enteric viruses, enumerated as MPN l−1 on MA-104 cell line. Identification of the isolated enteroviruses yielded 88.3% for Coxsackie virus B (1-5), 18.3% were positive for Polio (1-3) and 8.3% for Echo virus (1+11). The reduction rates of somatic bacteriophages ranged from 76.4% to 99.90%, for male specific bacteriophages from 87.5% to 99.9% and for E. coli. from 75.0% to 99.9% respectively. Two of the plants use standard chemical precipitation and the other two employ combinations of chemical and biological elimination techniques to reduce the concentrations of phosphorus and nitrogen. A correlation between the amount of precipitators and the elimination rates of the tested microorganisms could not be demonstrated, perhaps due to the fact that the treatment conditions could not be modified by the investigators. It is concluded that the tested treatment plants using combinations of chemical and biological techniques for P and N removal show equal or higher elimination rates than conventional treatment processes using chemical elimination techniques. biological phosphorus elimination, coliphages, E. coli, sewage treatment, virus adsorption, virus elimination This content is only available as a PDF. © IWA Publishing 2000 You do not currently have access to this content.

Phosphorus elimination by longitudinal subdivision of reservoirs and lakes

An epilimnetic volume of nearly 350,000 m3 was separated by the installation of an overflown, submerged flexible curtain (SFC, 160 m long, 6 m deep) perpendicular to the flow direction in the Haselbach mouth region of the Saidenbach Reservoir (Saxony, Germany). The SFC produced (i) an interruption of hydraulic short circuits between inlet and main reservoir basin, (ii) a longer retention time of the inflowing water, and (iii) a 30% to 40% increase of the elimination of soluble reactive phosphorus in the mouth region during summer stratification. It is conclusive that flexible curtains may be cost-effective substitutes for conventional pre-dams of thermally stratified lakes or reservoirs.

Phosphorus elimination by longitudinal subdivision of reservoirs and lakes1

An epilimnetic volume of nearly 350,000 m3 was separated by the installation of an overflown, submerged flexible curtain (SFC, 160 m long, 6 m deep) perpendicular to the flow direction in the Haselbach mouth region of the Saidenbach Reservoir (Saxony, Germany). The SFC produced (i) an interruption of hydraulic short circuits between inlet and main reservoir basin, (ii) a longer retention time of the inflowing water, and (iii) a 30% to 40% increase of the elimination of soluble reactive phosphorus in the mouth region during summer stratification. It is conclusive that flexible curtains may be cost-effective substitutes for conventional pre-dams of thermally stratified lakes or reservoirs.

The Importance of the Manganese‐Oxidizing Microorganism Metallogenium personatum for the Retention of Manganese in the Wahnbach Reservoir

AbstractThe retention of manganese in the water of the Wahnbach reservoir was determined in mass balance calculations. The retention properties for manganese drastically decreased after the phosphorus elimination plant was taken into service. Processes controlling the distribution and mobility of manganese in the reservoir were based on the results of tests conducted to evaluate the role of the microorganism Metallogenium personatum. A substantial retention of manganese in the Wahnbach reservoir was found to be dependent on the presence of this planktonic manganese‐oxidizing bacterium. The test results clearly indicate the importance of Metallogenium spec. as catalyst in the removal and oxidation of dissolved Mn(II).