Phosphate release from waste stabilisation pond sludge: significance and fate of polyphosphate

2011 ◽  
Vol 63 (8) ◽  
pp. 1689-1694 ◽  
Author(s):  
N. Powell ◽  
A. Shilton ◽  
S. Pratt ◽  
Y. Chisti
Keyword(s):  
Release Rate ◽  
Phosphorus Removal ◽  
Algal Bloom ◽  
Chemical Precipitation ◽  
Phosphorus Release ◽  
Common View ◽  
Phosphate Release ◽  
Initial Release ◽  
Polyphosphate Accumulation ◽  
The Common

Net phosphorus removal from waste stabilisation pond (WSP) systems is governed by the rate of phosphorus incorporation into the sludge layer and the rate of phosphorus release from this sludge back to the overlying wastewater. Luxury uptake of phosphorus by microalgae has been shown to occur under WSP conditions in the laboratory; however, the significance of this mechanism and the fate of polyphosphate contained in the settled solids have not previously been investigated. In this work the analysis of sludge samples from three WSP showed that up to 71% of the total phosphorus in the sludge was in the form of polyphosphate. This indicates that polyphosphate accumulation could potentially be an important mechanism for phosphorus sequestration in WSP and challenges the common view that chemical precipitation is the predominant phosphorus removal mechanism in these systems. The release of phosphate from WSP sludge samples was monitored in the laboratory. The samples from two different pond systems had release rates in the order of 4.3 μgP/gTSS.d. However, the third sample which was collected during an algal bloom had a release rate of 12.4 μgP/gTSS.d. Phosphate release from fresh microalgal sludge grown under laboratory conditions was also studied and was shown to have a release rate of 160 μgP/gTSS.d. Analysis of polyphosphate during the experiments on laboratory grown microalgal sludge showed that polyphosphate was indeed degraded resulting in phosphate release. Interestingly, after the initial release phase phosphorus was assimilated by the biomass and some polyphosphate was reformed. It is likely that this is due to bacterial growth in the sludge.

Use of phosphorus release batch tests for modelling an EBPR pilot plant

2002 ◽  
Vol 45 (6) ◽  
pp. 99-106 ◽  
Author(s):  
E. Tykesson ◽  
H. Aspegren ◽  
M. Henze ◽  
P.H. Nielsen ◽  
J. Ia C. Jansen
Keyword(s):  
Release Rate ◽  
Phosphorus Removal ◽  
Pilot Plant ◽  
Phosphorus Content ◽  
Phosphorus Release ◽  
Biological Phosphorus Removal ◽  
Batch Tests ◽  
Initial Release ◽  
Analysis Programme ◽  
Biological Phosphorus

The aim of this study was to evaluate how routinely performed phosphorus release tests could be used when modelling enhanced biological phosphorus removal (EBPR) using activated sludge models such as ASM2d. A pilot plant with an extensive analysis programme was used as basis for the simulations. Without any calibration the prediction of phosphorus removal was poor and the initial release rates from the simulations were not similar to those found from the laboratory tests. A period with low organic loading was chosen as a calibration period. In this period averages of daily influent measurements were used as influent parameters. First, calibration was performed in order to fit effluent COD and MLVSS in the sludge. Next, the phosphorus content in the sludge was decreased to the measured level by decreasing the fermentation rate. Finally, the initial phosphorus release rate was calculated from a simulated batch test and the PHA uptake rate was increased to fit this release rate with the average initial rates from laboratory batch tests performed during the period. The calibrated model was verified with data from the subsequent period where acetate was dosed.

Phosphorus removal from nightsoil with sequencing batch reactor (SBR)

1997 ◽  
Vol 36 (12) ◽  
pp. 55-60 ◽  
Author(s):  
S. W. Oa ◽  
E. Choi
Keyword(s):  
Chemical Reactions ◽  
Phosphorus Removal ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Chemical Precipitation ◽  
Phosphorus Release ◽  
Biological Nutrient Removal ◽  
Biological Phosphorus Removal ◽  
P Fractionation ◽  
Biological Phosphorus

Phosphorus removal characteristics are rather complicated in a highly nitrogenous waste like nightsoil under treatment with SBR (sequencing batch reactor). It was found that the increased pH due to denitrification in anaerobic period stimulated chemical precipitation of phosphorus as struvite and hydroxyapatite, and the depressed pH due to nitrification in the aerobic period dissolved the previously formed precipitates. Phosphate accumulating organisms (PAO) worked as in the ordinary BNR (biological nutrient removal) systems regardless of the chemical reactions, but the chemical reactions masked the biological phosphorus release and uptake reactions. About 36% of phosphorus applied was removed biologically in polyphosphate granules. P-fractionation of sludges confirmed this phenomenon. Biological phosphorus removal could be increased with the increased anaerobic period. The morphological types of phosphorus precipitates were examined by SEM in combination with x-ray diffraction.

Articulatory Generalization in Two Word-Medial, Ambisyllabic Contexts

1988 ◽  
Vol 19 (3) ◽  
pp. 251-258 ◽  
Author(s):  
Virginia I. Wolfe ◽  
Suzanne D. Blocker ◽  
Norma J. Prater
Keyword(s):  
Common View ◽  
Perceptual Salience ◽  
The Common ◽  
Unitary Concept ◽  
Over Time

Articulatory generalization of velar cognates /k/, /g/ in two phonologically disordered children was studied over time as a function of sequential word-morpheme position training. Although patterns of contextual acquisition differed, correct responses to the word-medial, inflected context (e.g., "picking," "hugging") occurred earlier and exceeded those to the word-medial, noninflected context (e.g., "bacon," "wagon"). This finding indicates that the common view of the word-medial position as a unitary concept is an oversimplification. Possible explanations for superior generalization to the word-medial, inflected position are discussed in terms of coarticulation, perceptual salience, and the representational integrity of the word.

Current issues in aesthetics and beyond: Revisiting lookism

2020 ◽  
Vol 10 (1-2) ◽  
pp. 59-68
Author(s):  
Peter Takáč
Keyword(s):  
Plastic Surgery ◽  
Social Impact ◽  
Human Beings ◽  
Common View ◽  
Aesthetic Medicine ◽  
Unequal Treatment ◽  
Self Confidence ◽  
Public Status ◽  
The Social ◽  
The Common

AbstractLookism is a term used to describe discrimination based on the physical appearance of a person. We suppose that the social impact of lookism is a philosophical issue, because, from this perspective, attractive people have an advantage over others. The first line of our argumentation involves the issue of lookism as a global ethical and aesthetical phenomenon. A person’s attractiveness has a significant impact on the social and public status of this individual. The common view in society is that it is good to be more attractive and healthier. This concept generates several ethical questions about human aesthetical identity, health, authenticity, and integrity in society. It seems that this unequal treatment causes discrimination, diminishes self-confidence, and lowers the chance of a job or social enforcement for many human beings. Currently, aesthetic improvements are being made through plastic surgery. There is no place on the human body that we cannot improve with plastic surgery or aesthetic medicine. We should not forget that it may result in the problem of elitism, in dividing people into primary and secondary categories. The second line of our argumentation involves a particular case of lookism: Melanie Gaydos. A woman that is considered to be a model with a unique look.

PERSOALAN KEHIDUPAN KONTEMPORER: MENGGAGAS KAJIAN SACHEDINA TENTANG THEOLOGI PLURALISME

EMPIRISMA ◽  
2017 ◽  
Vol 26 (1) ◽  
Author(s):  
Limas Dodi
Keyword(s):  
Religious Pluralism ◽  
Main Argument ◽  
Religious Groups ◽  
Common View ◽  
The Public ◽  
The People ◽  
Muslim Majority ◽  
The Common ◽  
The Relationship ◽  
Religious Differences

According to Abdulaziz Sachedina, the main argument of religious pluralism in the Qur’an based on the relationship between private belief (personal) and public projection of Islam in society. By regarding to private faith, the Qur’an being noninterventionist (for example, all forms of human authority should not be disturb the inner beliefs of individuals). While the public projection of faith, the Qur’an attitude based on the principle of coexistence. There is the willingness of the dominant race provide the freedom for people of other faiths with their own rules. Rules could shape how to run their affairs and to live side by side with the Muslims. Thus, based on the principle that the people of Indonesia are Muslim majority, it should be a mirror of a societie’s recognizion, respects and execution of religious pluralism. Abdul Aziz Sachedina called for Muslims to rediscover the moral concerns of public Islam in peace. The call for peace seemed to indicate that the existence of increasingly weakened in the religious sense of the Muslims and hence need to be reaffi rmed. Sachedina also like to emphasize that the position of peace in Islam is parallel with a variety of other doctrines, such as: prayer, fasting, pilgrimage and so on. Sachedina also tried to show the argument that the common view among religious groups is only one religion and traditions of other false and worthless. “Antipluralist” argument comes amid the reality of human religious differences. Keywords: Theology, Pluralism, Abdulaziz Sachedina

Anaerobic Digestion of Primary Sludge Containing Iron Phosphate

1973 ◽  
Vol 8 (1) ◽  
pp. 91-109 ◽  
Author(s):  
M.E. Jack ◽  
G.J. Farquhar ◽  
G.M. Cornwall
Keyword(s):  
Anaerobic Digestion ◽  
Phosphorus Removal ◽  
Municipal Wastewater ◽  
Iron Phosphate ◽  
Chemical Precipitation ◽  
Task Group ◽  
Iron Compounds ◽  
Primary Sludge ◽  
Group Report ◽  
Aluminum Compounds

Abstract The importance of phosphorus as a nutrient in the eutrophication of lakes and rivers has been well established (Fruh 1967). It has been shown in addition that a significant amount of this phosphorus arises from the discharge of treated and untreated municipal wastewater (Task Group Report 1967). Consequently, measures are being taken, notably in the Province of Ontario, for removal of phosphorus from wastewater by means of chemical precipitation. Chemicals exhibiting satisfactory phosphorus removal include lime, iron compounds and aluminum compounds (Leckie and Stumm 1970; Schmid 1968; Wuhrman 1968).

Full Scale Study of Biological Phosphorus Removal Processes

1985 ◽  
Vol 17 (11-12) ◽  
pp. 297-298 ◽  
Author(s):  
Takao Murakami ◽  
Atsushi Miyairi ◽  
Kazuhiro Tanaka
Keyword(s):  
Flow Rate ◽  
Phosphorus Removal ◽  
Phosphorus Release ◽  
Full Scale ◽  
Aeration Tank ◽  
Biological Phosphorus Removal ◽  
Mode 2 ◽  
Removal Processes ◽  
Biological Phosphorus ◽  
Total P

In Japan various biological phosphorus removal processes have recently been researched by laboratory or pilot plant scale studies and most of them have shown good results. Based on these results, the Japan Sewage Works Agency has conducted a full scale study of the biological phosphorus removal process from June 1982 until February 1983, which was the first full scale operation of this process in Japan. The main purpose of the study was to evaluate phosphorus removal efficiency and also nitrogen removal efficiency of the process and in addition, to ascertain the important operating factors of the process. For the study a treatment train of a large scale sewage treatment plant was remodelled. The aeration tank of 3.825 m3 volume was divided into four equal cells. The whole train including return sludge line was operated entirely independently of the other trains. During the experiment the train was operated under two different modes, Mode 1 and Mode 2. In Mode 1, the train was operated as an A/O process, the first cell of the aeration tank being anaerobic and the other cells oxic. In Mode 2, the train was operated as a Modified Phoredox process. In this case, the first cell was anaerobic, but the second cell was anoxic and nitrified liquor was returned to it from the end of the oxic cells. Mode 1 and Mode 2 were further divided into many ‘runs' and the flow rate varied between 12,550 m3 d−1 and 25,270 m3 d−1 , corresponding to retention times of 7.3 hours and 3.6 hours, respectively. Throughout the experimental period the mean value of influent (primary effluent) total-P concentration was 3.38 mg 1−1 , and that of the final effluent was 0.47 mg 1−1 . A cumulated frequency curve of the data showed that about 93% of measured effluent total-P was below 1.0 mg l−1 . Therefore, it can be concluded that with these influent total-P levels, biological phosphorus removal processes can sufficiently satisfy the effluent standard of 1 mg 1−1 total-P. Even when the process was operated as a Modified Phoredox Process, no obstruction to phosphorus removal because of nitrification was observed and phosphorus removal remained good. However, since the sewage treatment plant treated influent from a combined sewerage system, phosphorus removal was sometimes affected by heavy rainfalls. In such cases phosphorus release in the anaerobic cell was insufficient because of increased influent NOx concentration and accordingly increased denitrification level in the anaerobic cell. Therefore, as a result, enhanced phosphorus uptake in the following cells could not be observed. Higher process stability can be expected if an effective countermeasure to high influent NOx concentration can be made. Influence of flow rate fluctuation on the process was also studied. The treatment train was operated for a week under a daily flow rate fluctuation pattern which ranged between 460 m3 hr−1 and 820 m3 hr−1 . Nevertheless, the effluent total-P concentration showed no increase and stayed constantly lower than 0.5 mg 1−1. The oxidation reduction potential (ORP) was an effective control index to evaluate the degree of phosphorus release in the anaerobic cell. Water temperature did not affect phosphorus release and uptake rates.

Operation Experiences with Biological Phosphorus Removal at the Sewage Treatment Plants of Berlin (West)

1991 ◽  
Vol 24 (7) ◽  
pp. 133-148 ◽  
Author(s):  
A. Peter ◽  
F. Sarfert
Keyword(s):  
Phosphorus Removal ◽  
Sewage Treatment ◽  
Chemical Precipitation ◽  
Biological Phosphorus Removal ◽  
Treatment Results ◽  
Sewage Treatment Plants ◽  
Research Activities ◽  
Two Stages ◽  
The Given ◽  
Biological Phosphorus

In investigations concerning sludge bulking in Berlin enhanced biological phosphorus removal was first observed unexpectedly. Because since 1986 an officially preset limit of 2 mg TP/l must be kept in all Berlin wastewater discharges it was decided to explore the capabilities of the observed mechanism under the specific circumstances of the exciting two large treatment plants in Ruhleben (240,000 m3/d) and Marienfelde (100,000 m3/d). For this purpose some of the existing units at both plants were equipped with anaerobic zones which were generated mainly by process modifications. Additionally stage one of the Ruhleben plant was altered completely in order to investigate the combination of biological phosphorus and nitrogen removal as a special pilot study in three parallel trains. The research activities and treatment results gained in each of the two stages of the Ruhleben and in the Marienfelde plant are reported in detail. For example BOD-related phosphorus removal rates were obtained ranging from 2.3-4.5 mg TP per 100 mg BOD removed. It must be stressed that all examinations were performed on full-scale conditions. At present the given limit of 2 mg TP/l in the Ruhleben plant is met without any chemical precipitation at least on average. From the beginning biological phosphorus removal will be integrated into further projected extensions.

Phosphorus Release Kinetics in Biofilm Reactors

1992 ◽  
Vol 26 (3-4) ◽  
pp. 567-576 ◽  
Author(s):  
F. A. Ruiz-Treviño ◽  
S. González-Martínez ◽  
C. Doria-Serrano ◽  
M. Hernández-Esparza
Keyword(s):  
Phosphorus Removal ◽  
Release Kinetics ◽  
Phosphorus Release ◽  
Organic Substrate ◽  
Biofilm Reactor ◽  
Substrate Uptake ◽  
Biofilm Reactors ◽  
Initial Substrate ◽  
Linear Behaviour ◽  
Substrate Concentrations

This paper presents the kinetic analysis, using Generalized Power-Law equations to describe the results of an experimental investigation conducted on a batch submerged biofilm reactor for phosphorus removal under an anaerobic/aerobic cycle. The observed rates and amounts of phosphorus release and organic substrate uptake in the anaerobic phase leads to a kinetic model in which these two variables are dependent on each other with a non-linear behaviour and reach equilibrium values in both cases, at different times and are function of rate constants ratio. The model has a good fit with experimental data except for C uptake at anaerobic contact times longer than four hours, where other kinetics are implied. Kinetic parameters were obtained with different initial substrate concentrations, anaerobic contact cycles, and type of substrates.

Non-steady variations of SOD and phosphate release rate due to changes in the quality of the overlying water

2000 ◽  
Vol 42 (3-4) ◽  
pp. 265-272 ◽  
Author(s):  
T. Inoue ◽  
Y. Nakamura ◽  
Y. Adachi
Keyword(s):  
Release Rate ◽  
Oxygen Demand ◽  
Phosphate Concentration ◽  
Sediment Oxygen Demand ◽  
Biochemical Reactions ◽  
Overlying Water ◽  
Phosphate Release ◽  
Do Concentration ◽  
The Difference

A dynamic model, which predicts non-steady variations in the sediment oxygen demand (SOD) and phosphate release rate, has been designed. This theoretical model consists of three diffusion equations with biochemical reactions for dissolved oxygen (DO), phosphate and ferrous iron. According to this model, step changes in the DO concentration and flow velocity produce drastic changes in the SOD and phosphate release rate within 10 minutes. The vigorous response of the SOD and phosphate release rate is caused by the difference in the time scale of diffusion in the water boundary layer and that of the biochemical reactions in the sediment. Secondly, a negative phosphate transfer from water to sediment can even occur under aerobic conditions. This is caused by the decrease in phosphate concentration in the aerobic layer due to adsorption.

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