Potential Utilization of OECD 302 B Test in Biodegradability Assessment of Metalworking Fluids

2013 ◽  
Vol 726-731 ◽  
pp. 2256-2259
Author(s):  
Kristina Gerulova ◽  
Jozef Fiala ◽  
Zuzana Szabova ◽  
Eva Buranská ◽  
Petra Paulocikova ◽  
...  

The main aim of this study was to evaluate the ability of the activated sludge from sewage treatment plant to degrade a part of the 12 randomly selected metalworking fluids (MWFs) according to OECD 302B (with different addition of activated sludge AS 0.25 g/l, 0.50 g/l and 1.00 g/l of suspended solids - SS). The degradability test showed that, after the first 3 hours of cultivating, adsorption grew with the increasing amount of inoculums. In the case of AS addition 1.00 g/l of SS were the adsorption rate lower than 20 % in four samples, in the case of AS addition 0.50 g/l of SS in 9 samples and in the case of AS addition 0.25 g/l of SS in all 12 tested samples. In four samples were also observed the lag phase (adaptation of the bacterias to the presented carbon source). If occur adsorption rate more than 20% it is probably impossible to distinguish biological degradation of organic matter from abiotic elimination from the suspension.

1988 ◽  
Vol 20 (4-5) ◽  
pp. 143-152 ◽  
Author(s):  
M. Tendaj-Xavier ◽  
J. Hultgren

Bromma sewage treatment plant is the second largest plant in Stockholm with a design flow of 160,000 m3/d. The wastewater is treated mechanically, chemically by pre-precipitation with ferrous sulphate, and biologically by the activated sludge process. The requirements for the plant are 8 mg BOD7/l, 0.4 mg P/l and 2 mg NH4+-N/l. The requirement for ammonia refers to the period July-October. In order to meet those rather stringent requirements, the biological step was expanded 3 years ago with 6 new sedimentation tanks. The 6 new tanks have the same area as the 6 old ones but they have only a depth of 3.7 m compared with the depth of the old tanks, 5.7 m. Experience from the first years of operation of the new tanks is that these tanks are more sensitive and less efficient than the older ones. It seems that the effluent suspended solids concentration from the old tanks is less influenced by rapid flow variations than the concentration in the effluent from the new secondary sedimentation tanks. During the nitrification period denitrification takes place to some degree in the secondary sedimentation tanks. This may cause loss of solids and it has been observed that the deeper old tanks usually produce an effluent of better quality and seem to be less influenced by denitrification than the new ones.


2017 ◽  
Vol 35 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Michał Marzec

AbstractThe reliability of removal of selected contaminants in three technological solutions of the household sewage treatment plants was analysed in this paper. The reliability of the sewage treatment plant with activated sludge, sprinkled biological deposit and hybrid reactor (activated sludge and immersed trickling filter) was analyzed. The analysis was performed using the Weibull method for basic indicators of impurities, BOD5, COD and total suspended solids. The technological reliability of the active sludge treatment plant was 70% for BOD5, 87% for COD and 66% for total suspended solids. In the sewage treatment plant with a biological deposit, the reliability values determined were: 30% (BOD5), 60% (COD) and 67% (total suspended solids). In a treatment plant with a hybrid reactor, 30% of the BOD5and COD limit values were exceeded, while 30% of the total suspended solids were exceeded. The reliability levels are significantly lower than the acceptable levels proposed in the literature, which means that the wastewater discharged from the analysed wastewater treatment plants often exceeds the limit values of indicators specified in currently valid in Poland Regulation of the Minister of Environment for object to 2000 population equivalent.


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 ◽  
...  

2008 ◽  
Vol 58 (5) ◽  
pp. 1101-1106
Author(s):  
Pichiah Saravanan ◽  
K. Pakshirajan ◽  
P. K. Saha

An indigenous mixed culture of microorganisms, isolated from a sewage treatment plant, was investigated for its potential to simultaneously degrade phenol and m-cresol during its growth in batch shake flasks. 22 full factorial designs with the two substrates as the factors, at two different levels and two different initial concentration ranges, were employed to carry out the biodegradation experiments. For complete utilisation of phenol and m-cresol, the culture took a minimum duration of 21 hrs at their low concentration of 100 mg/L each, and a maximum duration of 187 hrs at high concentration of 600 mg/L each in the multisubstrate system. The biodegradation results also showed that the presence of phenol in low concentration range (100–300 mg/L did not inhibit m-cresol biodegradation; on the other hand, presence of m-cresol inhibited phenol biodegradation by the culture. Moreover, irrespective of the concentrations used, phenol was degraded preferentially and earlier than m-cresol. During the culture growth, a lag phase was observed above a combined concentration of 500 mg/L i.e., 200 mg/L m-cresol and 300 mg/L of phenol and above). Statistical analysis of the specific growth rate of the culture in the multisubstrate system was also performed in the form of ANOVA and Student ‘t’ test, which gave good interpretation in terms of main and interaction effects of the substrates.


2002 ◽  
Vol 46 (10) ◽  
pp. 173-179 ◽  
Author(s):  
S. Tanaka ◽  
K. Kamiyama

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.


2004 ◽  
Vol 46 (6) ◽  
pp. 309-313 ◽  
Author(s):  
Luciana Urbano Santos ◽  
Taís Rondello Bonatti ◽  
Romeu Cantusio Neto ◽  
Regina Maura Bueno Franco

Giardia and Cryptosporidium have caused several outbreaks of gastroenteritis in humans associated with drinking water. Contaminated sewage effluents are recognized as a potential source of waterborne protozoa. Due to the lack of studies about the occurrence of these parasites in sewage samples in Brazil, we compared the efficiency of two procedures for concentrating cysts and oocysts in activated sludge samples of one sewage treatment plant. For this, the samples were submitted to i) concentration by the ether clarification procedure (ECP) and to ii) purification by sucrose flotation method (SFM) and aliquots of the pellets were examined by immunofluorescence. Giardia cysts were present in all samples (100.0%; n = 8) when using ECP and kit 1 reagents, while kit 2 resulted in six positive samples (85.7%; n = 7). As for SFM, cysts were detected in 75.0% and 100.0% of these samples (for kit 1 and 2, respectively). Regarding Cryptosporidium, two samples (25.0%; kit 1 and 28.5% for kit 2) were detected positive by using ECP, while for SFM, only one sample (examined by kit 1) was positive (12.5%). The results of the control trial revealed Giardia and Cryptosporidium recovery efficiency rates for ECP of 54.5% and 9.6%, while SFM was 10.5% and 3.2%, respectively. Considering the high concentration detected, a previous evaluation of the activated sludge before its application in agriculture is recommended and with some improvement, ECP would be an appropriate simple technique for protozoa detection in sewage samples.


2013 ◽  
Vol 361-363 ◽  
pp. 1032-1035
Author(s):  
Xi Tian ◽  
Sheng Shu Ai ◽  
Yan Zuo ◽  
Qing Kai Ren ◽  
Zhong Yan Xie

At the sewage temperatures of 7-15°C, it used biological video microscopy and scanning electron microscopy to detect activated sludge morphology, miniature animals and flora species in northern winter sewage treatment plant. The results showed that activated sludge had dense floc with sharp edge, and was bigger at the temperatures of 13 and 15°C than at the temperatures of 7, 9 and 11°C. When the autumn and winter seasons were alternate and the sewage temperature was instability, the edge of the floc was slightly fuzzy and there was a small amount of free bacteria in activated sludge floc. The study had also shown that the temperature was higher, the type of sludge miniature animal and flora species were richer.


2012 ◽  
Vol 573-574 ◽  
pp. 1106-1111
Author(s):  
Wen Wan Meng ◽  
Lei Liao ◽  
Fei Chao Zhao ◽  
Zhen Zhou Wei

Experiments according to the current domestic situation of bio-treatment cooking fume, domesticated the activated sludge which taken from the oxidation ditch of the sewage treatment plant by using the simulated cooking fumes, discussed the concentration and morphology variation of activated sludge, researched the degradation ability of microorganism on cooking fume, the change of bacteria amount were studied in the whole process. Research showed that the sludge concentration decreased to 2878mg/L when the acclimatization time reached 50days; outlet and inlet oil concentration were consistent when the acclimatization time reached 30days while liquid fume concentration decreased to 8.436mg/L, the degradation rate of activated sludge on liquid fume was about 75% after 30 days; Microbial biomass increased first and then down become stable finally.


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