Fatty acid methyl ester (FAME) technology was evaluated as a monitoring tool for quantification of Gordonia amarae in activated sludge systems. The fatty acid, 19:1 alcohol, which was identified as a unique fatty acid in G. amarae was not only confirmed to be present in foaming plant samples, but the quantity of the signature peak correlated closely with the degree of foaming. Foaming potential experiment provided a range of critical foaming levels that corresponded to G. amarae population. This range of critical Gordonia levels was correlated to the threshold signature FAME amount. Six full-scale wastewater treatment plants were selected based on a survey to participate in our full-scale study to evaluate the potential application of the FAME technique as the Gordonia monitoring tool. Greater amounts of signature FAME were extracted from the mixed liquor samples obtained from treatment plants experiencing Gordonia foaming problems. The amounts of signature FAME correlated well with the conventional filamentous counting technique. These results demonstrated that the relative abundance of the signature FAMEs can be used to quantitatively monitor the abundance of foam-causing microorganism in activated sludge.
One of the most important factors limiting the development of industrial processes is the consumption of large amounts of clean water and the generation of large amounts of wastewater. Pigments are available in a wide range of colors, consisting of small molecules practically insoluble in the medium and known to be unique compounds for many industries. They are widely used in dyestuff, cosmetics, food products, pharmaceuticals, manufacturing processes, etc. This study focuses on the removal of pigments and other components from wastewater discharged from pigment plants. The separation process was carried out in two stages: the first was to use prepared activated carbon as an adsorbent to separate the pigment, and then the separation process by electrodialysis to remove other components such as salts, acids, and others. This study considers prepared activated carbon (AC) as an effective separating adsorbent. The preparation process mainly included two-stage pyrolysis and activation using potassium hydroxide (KOH) and sodium hydroxide (NaOH).
The purpose of this study was to investigate the toxicological response of nitrifying and heterotrophic populations in activate sludge to different copper concentrations. The changes in the active fraction of nitrifying and heterotrophic communities were quantitatively estimated by the respirometric analysis. Furthermore, the shift in community structure of mixed culture receiving continuous dose of copper was qualitatively determined by the fatty acid methyl esters (FAMEs) analysis and principal component analysis (PCA).Four bench-scale activated sludge units were fed with synthetic wastewater and operated at a mean cell residence time (MCRT) of 20 days. Copper concentrations in the influent were 0, 1, 3 and 6 mg/L. Toxicological responses of the nitrifying and heterotrophic populations were evaluated by the normalized ammonia uptake rate (AUR) and total organic carbon (TOC) removal rate, respectively. Substantial decrease in the performance of both nitrifiers and heterotrophs were observed at the copper concentrations of 3 and 6mg/L.In order to examine the effect of continuous dose of copper on viable population of nitrifiers and heterotrophs, the active fraction of both populations were estimated by a respirometric technique. Active fractions of the nitrifiers and hetertrophs in the noninhibited control unit were 1.0 and 30.1% of total biomass, respectively. The active fractions both populations decreased sharply to 0.1 and 0.5% (for nitrifier and heterotrophs, respectively) under the continuous dose of 3 mg/L, suggesting that the continuous loading of copper as low as 3 mg/L is enough to have detrimental effects on the viable communities in nitrifying activated sludge.Effect of copper on microbial community structure was evaluated by FAME analysis. Nineteen fatty acids were extracted from the samples harvested from the bench-scale activated sludge units. Of those fatty acids, seven were previously identified as fatty acids typically present in pure cultures of Nitrosomonas spp. and Nitrobacter spp. When fatty acid compositions of both nitrifying FAMEs and all FAMEs were examined by PCA, the resulting plots showed clear distinctions between populations in control units and those that exhibited decreased levels of nitrification. The combination of FAME analysis with PCA illustrated the significant shift in the nitrifying and heterotrophic community structure as a result of continuous copper dosage.
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