The Behaviour of Chlorinated Organics during Activated Sludge Treatment and Anaerobic Digestion

1988 ◽  
Vol 20 (11-12) ◽  
pp. 353-359 ◽  
Author(s):  
P. W. W. Kirk ◽  
J. N. Lester
Keyword(s):  
Biological Activity ◽  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Sewage Treatment ◽  
Chemical Degradation ◽  
Organic Micropollutants ◽  
Sludge Treatment ◽  
Primary Sludge ◽  
Chlorinated Organic ◽  
Rapid Removal

An activated sludge pilot plant was operated at 4,6 and 9d sludge ages with influent settled sewage from a full scale treatment works. The behaviour of the chlorinated organic micropollutants was examined at their background levels in sewage and significant removal was seen for dieldrin, Y-HCH, DDE, PCB and 2,4-DCPol at all sludge ages. Dieldrin, Y-HCH, DDE PCB, 2,4,5-TCPol, 2,4,6-TCPol and 2,4-DCPol were found to associate with activated sludge solids. 2,4-DCPol and 4-C-2MPol were found to be biologically degraded. Mixed primary sludge from the same sewage treatment works was incubated anaerobically with and without azide addition to prevent biological activity. Rapid removal of Y-HCH was concluded to be due to chemical degradation, while biological activity was concluded to be the mechanism for the removals of 2,4-D, 2,4,5-T, 2,4,6-TCPol and 2,3,4,6-TeCPol. Statistically significant increases were observed for 2,3,4,6-TeCPol in azide treated incubations and for 2,4,5-TCPol and 2,4-DCPol in both treated and untreated anaerobic sludges.

Removal and inactivation of cryptosporidium oocysts by activated sludge treatment and anaerobic digestion

1995 ◽  
Vol 31 (5-6) ◽  
pp. 97-104 ◽  
Author(s):  
K. L. Stadterman ◽  
A. M. Sninsky ◽  
J. L. Sykora ◽  
W. Jakubowskii
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Sewage Treatment ◽  
Treatment Plant ◽  
Sludge Treatment ◽  
Treatment Processes ◽  
Secondary Effluents ◽  
Immunofluorescent Technique ◽  
Cryptosporidium Parvum Oocysts

To determine the fate of Cryptosporidium parvum oocysts during wastewater treatment, a model of an activated sludge treatment plant was designed with a flow of 17 ml/min and a detention time of 6 hours. Samples of raw sewage were seeded with oocysts and primary and secondary effluents were analyzed for C. parvum using an immunofluorescent technique. To compare removal efficiencies of oocysts by various wastewater treatment processes, raw sewage, activated sludge, trickling filter and biodisc effluents were seeded with oocysts and settled for 2 hr and for the respective detention times. Sludge produced by a wastewater treatment plant and anaerobically digested at 37° C in a laboratory digester was also seeded with C. parvum oocysts. Oocyst inactivation was measured by excystation and direct counts. Removal of oocysts in primary and secondary sedimentation averaged 83.4% and 90.7% respectively. The total oocyst removal in sewage treatment averaged 98.6%. In comparison with other treatment processes, activated sludge had the maximum oocyst removal efficiency at 92%. The anaerobic digestion process inactivated 90% of the oocysts within four hours of exposure. 99.9% of the oocysts were eliminated by anaerobic digestion after 24 hours. This demonstrates that the activated sludge process and anaerobic digestion can be effective for the removal and inactivation of C. parvum oocysts.

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%.

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.

Waste activated sludge treatment based on temperature staged and biologically phased anaerobic digestion system

2013 ◽  
Vol 25 (10) ◽  
pp. 2056-2064 ◽  
Author(s):  
Jingwen Yu ◽  
Mingxia Zheng ◽  
Tao Tao ◽  
Jiane Zuo ◽  
Kaijun Wang
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Waste Activated Sludge ◽  
Sludge Treatment

The Transformation of Heavy Metal Be in Activated Sludge Process

2012 ◽  
Vol 178-181 ◽  
pp. 633-636 ◽  
Author(s):  
Feng Chen ◽  
Xiu Lian Zhu ◽  
Wei Yu
Keyword(s):  
Heavy Metal ◽  
Activated Sludge ◽  
Sewage Treatment ◽  
Great Influence ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Urban Land Use ◽  
Huge Number ◽  
Sludge Treatment

Municipalsludge is refers to the product of sewage treatment plant, facing the huge number of municipalsludge, the disposal of the municipalsludge has aroused wide attention of all countries. Many studies consider that urban land use of the municipalsludge is the most effective method, However heavy metal accumulats in the sludge and the environment of the risk with agricultural appears day after day.The purpose of this study is: analysis the transfermation of heavy metals in the activated sludge system of various structures. put forward the solution of reducing heavy metal exceeded in the activated sludge treatment process.It appears that the coagulation can make colloid stabilized and sedimentation, can control the input of the heavy metal effectively; Adsorption of activated sludge to heavy metal is very fast, in 30 min basic reached adsorption balance, probably 80% or more;The change from oxygen to aerobic have great influence on Heavy metal biological adsorption;An aerobic digestion processes can reduce the volume and quality of sludge, but there is no enrichment role to heavy metal in sludge.

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