Spatial arrangement of the components of activated sludge flocs

1994 ◽  
Vol 30 (11) ◽  
pp. 243-250 ◽  
Author(s):  
F. Zartarian ◽  
C. Mustin ◽  
J. Y. Bottero ◽  
G. Villemin ◽  
F. Thomas ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Laser Scanning ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Spatial Arrangement ◽  
Municipal Sewage ◽  
Cellular Division ◽  
Floc Size ◽  
Sludge Flocs

The purpose of this work was to observe the internal structure of activated sludge flocs and the relationship between the different components. Activated sludge flocs from the municipal sewage treatment plant at Nancy (France) were physically stabilized and solidified in an epoxy resin. The flocs were sliced into 0.1 μm thick sections and stained for characterisation of components and exopolymers by transmission electron microscopy. One small floc (10 μm × 20 μm), embedded in resin, was chosen and studied using a laser scanning confocal microscope. The focal plane was incremented in steps of 2 μm along the z axis of the microaggregate. In order to extract quantitative data (number of cells, floc size) a numerical treatment of the images was applied. A typical floc exhibits an unhomogeneous distribution of the mass of the exocellular polymer matrix (mainly polysaccharides). This matrix maintains the integrity of the floc and connects most of the components. These components are isolated bacteria, waste and debris inherited from the effluent and microcolonies. The structure of the microflocs is fractal with a fractal dimension Df ≈ 3. This large value implies that the growth of the small aggregates is possibly generated by cellular division and polymer production.

Thermochemical pretreatment in the anaerobic digestion of waste activated sludge

2002 ◽  
Vol 46 (10) ◽  
pp. 173-179 ◽  
Author(s):  
S. Tanaka ◽  
K. Kamiyama
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Municipal Sewage ◽  
Waste Activated Sludge ◽  
Anaerobic Digesters ◽  
Thermochemical Pretreatment ◽  
Methane Production Rate

Effects of a thermochemical pretreatment on the anaerobic digestion of waste activated sludge (WAS) was investigated by semicontinuously-fed digesters operated at 37¡C. WAS from a return sludge line of a municipal sewage treatment plant was pretreated by autoclaving at 130°C for 5 minutes after adding 0.3g NaOH/g VSS. Solids of WAS were thermochemically solubilized to one half and then 60% or more were in totality solubilized in anaerobic digesters fed with pretreated WAS at 2-8 days of hydraulic retention times (HRT), while only 16-36% were solubilized in digesters fed with raw WAS. The adverse effect of the set temperature (130°C) on the biodegradability of protein was not found. As a result, removal rates of COD in digestion was increased from 38% to 57% at 8 days HRT by the pretreatment. A specific methane production rate in the pretreated process was three times as high as the normal process. The thermochemical pretreatment was found to be very effective to enhance biodegradability as well as solubilization of WAS in anaerobic digestion.

Biosorption characteristics of reactive dye onto dried activated sludge

2006 ◽  
Vol 1 (3) ◽  
Author(s):  
Dong-Jin Ju ◽  
Im-Gyu Byun ◽  
Chang-Han Lee ◽  
Gab-Hwan An ◽  
Tae-Joo Park
Keyword(s):  
Activated Sludge ◽  
Langmuir Isotherm ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Reactive Dye ◽  
Municipal Sewage ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Initial Ph

This study examined the removal of reactive dye onto dead cells in activated sludge collected from the municipal sewage treatment plant in Suyoung, Pusan. The biosorption of reactive dye from aqueous solutions using the activated sludge was studied using a batch system with respect to the initial pH, temperature, amount of adsorbent and the pre-treatment of the adsorbent. Both the Freundlich and Langmuir isotherm models could describe the adsorption equilibrium of the reactive dye onto the activated sludge with the Langmuir isotherm showing the best agreement. First- and second-order kinetic models were used to investigate the adsorption mechanism. The adsorption capacity of Rhodamine-B(Rh-B) onto the activated sludge increased with decreasing initial pH and temperature.

Influence of Nitrate on the Bacterial Flora of Activated Sludge under Anoxic Condition

1991 ◽  
Vol 23 (4-6) ◽  
pp. 765-772 ◽  
Author(s):  
Jun-ichi Takeuchi
Keyword(s):  
Activated Sludge ◽  
Bacterial Species ◽  
Bacterial Flora ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Culture Technique ◽  
Municipal Sewage ◽  
Nitrate Content ◽  
A Site

A two-year survey of bacterial populations in activated sludge was carried out in a municipal sewage treatment plant receiving industrial wastewater having a high nitrate content. Phosphorus removal was not improved with a modified operation with a dissolved oxygen (DO)-deficient selector. In these circumstances, the anoxic selector in the aeration tanks acted as a site for denitrification not as a site for phosphate incorporation. The ecological interactions between the different bacterial species are thought to occur in the anoxic zone. Possible competition between the Pseudomonas/Alcaligenes group and the Acinetobacter/Moraxella group was suggested under laboratory conditions. Commensalism between the Enterobacter/Aeromonas group and the Acinetobacter/Moraxella group was observed by using a Nuclepore membrane-dialysis culture technique.

The Possible Utilization of Waste Sludge as an Adsorbent for Removal of Organic Vapor

1986 ◽  
Vol 18 (7-8) ◽  
pp. 413-420 ◽  
Author(s):  
P. C. Chiang ◽  
J. H. You
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Municipal Sewage ◽  
Methyl Ethyl ◽  
Organic Vapor ◽  
Waste Sludge ◽  
Catalyst Temperature ◽  
Major Factors ◽  
Municipal Sewage Treatment Plant

In this investigation it was found that the waste sludge obtained from a municipal sewage treatment plant could be reclaimed as an adsorbent for removal of organic vapours, i.e. toluene, methyl-ethyl-ketone and 1-1-2-trichloroethylene, through use of a pyrolysis technique. In order to find the optimum manufacturing process, several tests were performed under various conditions in which the addition of a catalyst, temperature control, and residence time in the furnace, were considered as the three major factors. Both the reclaimed adsorbent and commercially available activated carbon were evaluated to determine their adsorption capacity at various influent concentrations of organic vapours.

scholarly journals The Microbiota and Abundance of the Class 1 Integron-Integrase Gene in Tropical Sewage Treatment Plant Influent and Activated Sludge

PLoS ONE ◽  
2015 ◽  
Vol 10 (6) ◽  
pp. e0131532 ◽  
Author(s):  
Magna C. Paiva ◽  
Marcelo P. Ávila ◽  
Mariana P. Reis ◽  
Patrícia S. Costa ◽  
Regina M. D. Nardi ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Class 1 Integron ◽  
Integrase Gene ◽  
Class 1

scholarly journals The effect of purified sewage discharge from a sewage treatment plant on the physicochemical state of water in the receiver

2016 ◽  
Vol 48 (3) ◽  
pp. 267-284
Author(s):  
Włodzimierz Kanownik ◽  
Agnieszka Policht-Latawiec ◽  
Magdalena Wiśnios
Keyword(s):  
Water Saturation ◽  
Stream Water ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Fold Increase ◽  
Municipal Sewage ◽  
Stream Water Quality ◽  
Sewage Discharge ◽  
Physicochemical State

Abstract The paper presents changes in the contents of physicochemical indices of the Sudół stream water caused by a discharge of purified municipal sewage from a small mechanical-biological treatment plant with throughput of 300 m3·d−1 and a population equivalent (p.e.) – 1,250 people. The discharge of purified sewage caused a worsening of the stream water quality. Most of the studied indices values increased in water below the treatment plant. Almost a 100-fold increase in ammonium nitrogen, 17-fold increase in phosphate concentrations and 12-fold raise in BOD5 concentrations were registered. Due to high values of these indices, the water physicochemical state was below good. Statistical analysis revealed a considerable effect of the purified sewage discharge on the stream water physicochemical state. A statistically significant increase in 10 indices values (BOD5, COD-Mn, EC, TDS, Cl−, Na+, K+, PO43−, N-NH4+ and N-NO2) as well as significant decline in the degree of water saturation with oxygen were noted below the sewage treatment plant. On the other hand, no statistically significant differences between the water indices values were registered between the measurement points localised 150 and 1,000 m below the purified sewage discharge. It evidences a slow process of the stream water self-purification caused by an excessive loading with pollutants originating from the purified sewage discharge.

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