scholarly journals Adsorption and partitioning behaviour of selected trace polycyclic synthetic musks in a suspended growth aerobic activated sludge system

2021 ◽  
Author(s):  
Vince Pileggi
Keyword(s):  
Activated Sludge ◽  
Extracellular Polymeric Substances ◽  
Environmental Concern ◽  
Municipal Sewage ◽  
Sorption Behaviour ◽  
Synthetic Musks ◽  
Suspended Growth ◽  
Sludge Properties ◽  
Floc Properties ◽  
Activated Sludge Systems

This thesis investigated the influence of sludge retention time (SRT) and temperature (T) on selected activated sludge properties and their influence on partitioning and sorption behaviour of selected trace polycyclic synthetic musks (PSMs) of environmental concern. Suspended growth aerobic activated sludge systems under controlled temperature (10 and 20°C) and SRTs (3.5 and 10.5 days) conditions fed by municipal sewage were investigated. The selected PSMs monitored included Cashmeran, Celestolide, Phantolide, Traseolide, Galaxolide and Tonalide. Activated sludge floc properties including relative hydrophobicity (RH) and extracellular polymeric substances (EPS) showed significant differences which correlated well (r [subscript p] of ± 0.4 to ± 0.7) to the removal and partitioning of PSMs removed from the aqueous phase and associated with activated sludege. Galaxolide and Tonalide were found to represent over 95% of the total PSMs in both the aqueous and solid phases. PSMs aqueous reduction from 62 to 80% was observed. The total PSMs associated with sludge ranged from 15 to 27 [micro]g/g d.m. and the lowest concentration was observed under 10.5 days SRT and 20°C which also resulted in nitrifying conditions. SRT was the dominant operational factor, followed by SRT and TxSRT in influencing the partitioning of the PSMs and floc properties. The Freundlich equilibrium PSMs sorption and desorption isotherms, for sludges were generated and showed significant differences in sorption behaviour.

scholarly journals Adsorption and partitioning behaviour of selected trace polycyclic synthetic musks in a suspended growth aerobic activated sludge system

2021 ◽  
Author(s):  
Vince Pileggi
Keyword(s):  
Activated Sludge ◽  
Extracellular Polymeric Substances ◽  
Environmental Concern ◽  
Municipal Sewage ◽  
Sorption Behaviour ◽  
Synthetic Musks ◽  
Suspended Growth ◽  
Sludge Properties ◽  
Floc Properties ◽  
Activated Sludge Systems

This thesis investigated the influence of sludge retention time (SRT) and temperature (T) on selected activated sludge properties and their influence on partitioning and sorption behaviour of selected trace polycyclic synthetic musks (PSMs) of environmental concern. Suspended growth aerobic activated sludge systems under controlled temperature (10 and 20°C) and SRTs (3.5 and 10.5 days) conditions fed by municipal sewage were investigated. The selected PSMs monitored included Cashmeran, Celestolide, Phantolide, Traseolide, Galaxolide and Tonalide. Activated sludge floc properties including relative hydrophobicity (RH) and extracellular polymeric substances (EPS) showed significant differences which correlated well (r [subscript p] of ± 0.4 to ± 0.7) to the removal and partitioning of PSMs removed from the aqueous phase and associated with activated sludege. Galaxolide and Tonalide were found to represent over 95% of the total PSMs in both the aqueous and solid phases. PSMs aqueous reduction from 62 to 80% was observed. The total PSMs associated with sludge ranged from 15 to 27 [micro]g/g d.m. and the lowest concentration was observed under 10.5 days SRT and 20°C which also resulted in nitrifying conditions. SRT was the dominant operational factor, followed by SRT and TxSRT in influencing the partitioning of the PSMs and floc properties. The Freundlich equilibrium PSMs sorption and desorption isotherms, for sludges were generated and showed significant differences in sorption behaviour.

Relationship between flocculation of activated sludge and composition of extracellular polymeric substances

2003 ◽  
Vol 47 (12) ◽  
pp. 95-103 ◽  
Author(s):  
B.-M. Wilén ◽  
B. Jin ◽  
P. Lant
Keyword(s):  
Activated Sludge ◽  
Surface Properties ◽  
Negative Correlation ◽  
Extracellular Polymeric Substances ◽  
Treatment Plant ◽  
Volume Index ◽  
Physical Parameters ◽  
Floc Size ◽  
Flocculation Ability ◽  
Floc Properties

Activated sludge flocs are a flocculated mass of microorganisms, extracellular polymeric substances (EPS) and adsorbed organic and inorganic material. The structure of the flocs is very heterogeneous and flocs with very different properties and morphologies may occur, depending on the conditions in the activated sludge treatment plant and wastewater composition. Present thinking suggests that cations, such as calcium, create cationic bridges with EPS excreted by the bacteria and thereby hold the various floc constituents together. However, due to the complex and heterogeneous nature of activated sludge, the mechanisms have neither been thoroughly investigated nor successfully quantified. A better understanding and description of the biological flocculation process is necessary in order to establish more efficient operational strategies. The main aim of this study was to get a comprehensive and unique insight into the floc properties of activated sludge and to assess the relative impact of chemical and physical parameters. A variety of sludges from full scale treatment plants with different settling properties were characterised. The interrelationships between floc parameters such as composition of EPS, surface properties and floc structure, and their effect on the flocculation and separation properties were assessed. The results indicate that the EPS, both in terms of quantity and quality, are very important for the floc properties of the activated sludge. However, presence of filaments may alter the physical properties of the flocs considerably. The EPS showed positive correlations to sludge volume index (SVI) if only sludges with low or moderate numbers of filaments were included. The surface properties were more affected by the composition of the EPS than by the number of filaments. The EPS showed positive correlation to negative surface charge and a negative correlation to relative hydrophobicity and flocculation ability. The negative correlation between flocculation ability and amount of EPS was surprising. The shear sensitivity, measured as degree of erosion of flocs when subjected to shear, was more affected by floc size and number of filaments than amount of EPS.

The Effect of Metallic and Ionic Species on the Performance of a Biological Effluent Treatment System

1977 ◽  
Vol 12 (1) ◽  
pp. 191-212
Author(s):  
B. Volesky ◽  
Q. Samak ◽  
P. Waller
Keyword(s):  
Activated Sludge ◽  
Inorganic Ions ◽  
Industrial Effluents ◽  
Original Data ◽  
Ionic Species ◽  
Threshold Concentration ◽  
Effluent Treatment ◽  
Organic Load ◽  
Metallic Ions ◽  
Activated Sludge Systems

Abstract Review of the available results appearing in the recent literature is presented focusing particularly upon the effects of metallic ions such as Cr, Cu, Zn, Cd, Hg, V, Zn, Ni and Co. Some original data involving the effects of Na are presented and discussed. Development of parameters used in evaluating the influence of toxic or inhibitory species on the mixed microbial population of an activated sludge system is of crucial importance and different techniques employed such as BOD-COD-TOC-removal rates, Oxygen Uptake Rate, and others are discussed, showing relative inadequacy of currently applied assays. From the data available, certain trends can be discerned. There is a definite threshold concentration for each metallic ion, depending on the organic load of the feed. In the order of increasing toxicity to activated sludge systems reflected in lower BOD removals the following metals have been listed as inhibiting factors at concentrations starting from 1 ppm applied on a continuous basis: hexavalent chromium, cobalt, zinc, cadmium, trivalent chromium, copper and nickel. Metals in combination have not been reported to exhibit any significantly different effects as compared to those observed with individually introduced metallic ions. Tolerance of some activated sludge systems to shock loadings by various inorganic ions and metals is reviewed. The conclusions are of particular importance for estimating the performance of biox systems handling industrial effluents which are likely to contain toxic components of inorganic or metallic nature.

On the Problem of “Two-Phase” Activated Sludge

1991 ◽  
Vol 24 (7) ◽  
pp. 59-64 ◽  
Author(s):  
R. W. Szetela
Keyword(s):  
Activated Sludge ◽  
Single Phase ◽  
Phase System ◽  
Two Phase ◽  
Wastewater Treatment Process ◽  
Sludge Stabilization ◽  
Technological Advantage ◽  
In Series ◽  
State Models ◽  
Activated Sludge Systems

Steady-state models are presented to describe the wastewater treatment process in two activated sludge systems. One of these makes use of a single complete-mix reactor; the other one involves two complete-mix reactors arranged in series. The in-series system is equivalent to what is known as the “two-phase” activated sludge, a concept which is now being launched throughout Poland in conjunction with the PROMLECZ technology under implementation. Analysis of the mathematical models has revealed the following: (1) treatment efficiency, excess sludge production, energy consumption, and the degree of sludge stabilization are identical in the two systems; (2) there exists a technological equivalence of “two-phase” sludge with “single-phase” sludge; (3) the “two-phase” system has no technological advantage over the “single-phase” system.

The Use of Anoxic Selectors for the Control of Low F/M Activated Sludge Bulking

1989 ◽  
Vol 21 (6-7) ◽  
pp. 609-619 ◽  
Author(s):  
Y.-J. Shao ◽  
David Jenkins
Keyword(s):  
Organic Matter ◽  
Activated Sludge ◽  
Pilot Plant ◽  
Detention Time ◽  
Substrate Removal ◽  
Batch System ◽  
Sludge Bulking ◽  
N Removal ◽  
Soluble Substrate ◽  
Activated Sludge Systems

Laboratory and pilot plant experiments on anoxic selector activated sludge systems were conducted on two wastewaters in some cases supplemented with nitrate, acetate or glucose. To prevent bulking sufficient anoxic selector detention time and nitrate levels must be available to reduce selector effluent soluble COD to below 100 mg/l and to reduce readily metabolizable organic matter to virtually zero (< 1 mg/l). Soluble COD/NO3-N removal stoichiometry is in the range 6.0-6.7. Selector systems have elevated soluble substrate removal and denitrification rates compared to CSTR systems. These rates are not affected greatly by temperature (20-25°C) for CSTR sludges but are for selector sludges. Upon exhaustion of nitrate in a selector soluble COD leaks out of the activated sludge in significant amounts. Thiothrix sp. and type 021N denitrify only to NO2 and at much slower rates than Zoogloearamigera does to N2. A sequencing batch system provides an optimistic estimate of the SVI that can be obtained by an anoxic selector system.

Behaviour of Alkylphenol Polyethoxylate Surfactants and of Nitrilotriacetate in Sewage Treatment

1987 ◽  
Vol 19 (3-4) ◽  
pp. 449-460 ◽  
Author(s):  
W. Giger ◽  
M. Ahel ◽  
M. Koch ◽  
H. U. Laubscher ◽  
C. Schaffner ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Operating Conditions ◽  
Municipal Sewage ◽  
Sludge Treatment ◽  
Loading Rates ◽  
Treatment Conditions ◽  
Physico Chemical ◽  
Treated Sewage ◽  
Removal Efficiencies

Effluents and sludges from several municipal sewage treatment plants in Switzerland were analyzed for nonylphenol polyethoxylates (NPnEO, n=3-20), nonylphenol mono- and diethoxylate (NPlEO, NP2EO), corresponding nonylphenoxy carboxylic acids (NP1EC, NP2EC) and nonylphenol (NP). These chemicals derive from nonionic surfactants of the NPnEO-type, and specific analitical techniques were used to study their behaviour during mechanical-biological sewage and subsequent sludge treatment. The parent NPnEO-surfactants, with concentrations in raw and mechanically treated sewage from 400-2200 mg/m3, were relatively efficiently removed by the activated sludge treatment. The abundances of the different metabolites varied depending on treatment conditions. The refractory nature of NPl/2EO, NP and NPl/2EC was recognized. Both biotransformations and physico-chemical processes determine the behaviour and fate of nonylphenolic substances in sewage treatment. Nitrilotriacetate (NTA) was found in primary effluents at concentrations between 430 and 1390 mg/m3. The various treatment plants showed different removal efficiencies for NTA depending on the operating conditions. Activated sludge treatment with low sludge loading rates and nitrifying conditions removed NTA with efficiencies between 95 and 99%. High sludge loading caused a decrease in NTA removal efficiencies from 70% to 39%.

Prediction of Soluble Nickel Removal by Activated Sludge Using Free Metal Ion Concentrations

1987 ◽  
Vol 19 (3-4) ◽  
pp. 439-448 ◽  
Author(s):  
Jeppe S. Nielsen ◽  
Steve E. Hrudey ◽  
Frederick F. Cantwell
Keyword(s):  
Activated Sludge ◽  
Metal Ion ◽  
Municipal Sewage ◽  
Nickel Ion ◽  
Ion Concentrations ◽  
Untreated Sewage ◽  
Nickel Uptake ◽  
Nickel Removal ◽  
Free Metal ◽  
Free Metal Ion

Batch isotherm studies using spiked sewage samples containing a range of total soluble nickel concentrations typical of municipal sewage strongly suggested that it is the free (i.e. uncomplexed) nickel ion that is sorbed by activated sludge. Equations relating nickel uptake by activated sludge to free nickel ion concentrations and the extent of complexation in untreated sewage were developed and applied. Predicted and measured nickel removals generally agreed to within ± 30%.

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