Examination of mercury's effects during the process of the activated sludge

Pavlogeorgatos, Gerasimos; Lekkas, Themistokles D.; Georgiou, V.; Spachos, G.; Stefanoulis, C.; Tridimas, P.

doi:10.1080/02772249909358699

Cited by 5 publications

(3 citation statements)

References 6 publications

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“…In a more detailed way, there was an increase in the concentration of the SS with a diameter larger than 122.87 mm and a respective decrease in the concentration of the smaller SS. This is an observation that is associated with the changes in the number and species of the bacteria in the aeration tank, before and after the introduction of mercury [1,19] and it probably indicates a possible way that microorganisms of the aeration tank react to the introduction of mercury. …”

Section: Discussionmentioning

confidence: 99%

Effect of mercury-contaminated wastewater on activated sludge suspended solids size distribution

Pavlogeorgatos

2003

Toxicological & Environmental Chemistry

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The primal purpose of this research project is to examine the size distribution of the Suspended Solids (SS) of an activated sludge pilot plant, under different operational conditions and during the introduction of wastewater contaminated with mercury of different concentrations (10-100 mg/L Hg(NO 3 ) 2 ). While the experiment was being conducted, the most important parameters of the pilot plant (COD, TOC, MLSS, SS, NH 4 , PO 4 , total number of bacteria -coccoids and rods, pH, DO, T etc.) were measured; this fact led to the inference of conclusions that connect the distribution of the size of the SS with those parameters. The main conclusions of this research work are: (a) the important interaction of the removal ability of the organic loading of the plant and the size distribution of the SS at the aeration tank and the outlet of the plant and (b) the input of the mercury-contaminated wastewater at the plant affects the size distribution of the SS at the aeration tank. The second conclusion probably indicates a possible way that microorganisms of the aeration tank react to the introduction of mercury.

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Section: Discussionmentioning

confidence: 99%

Effect of mercury-contaminated wastewater on activated sludge suspended solids size distribution

Pavlogeorgatos

2003

Toxicological & Environmental Chemistry

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“…In an early study, Ghosh and Zugger (1973) reported that concentration of Hg(II) less than 2.5 mg l −1 had little effect on aerobic process, but aerobic processes were definitely inhibited at concentrations higher than 5 mg l −1 . Concentration of Hg(II) equal to 0.1 mg l −1 did not influence the removal of chemical oxygen demand (COD), but favored the generation of larger biological flocs (Pavlogeorgatos et al, 1999). In a follow-up study, Stasinakis et al (2003c) investigated the effect of Hg(II) and CH 3 Hg + on heterotrophic respiration rate of activated sludge microorganisms.…”

Section: Mercurymentioning

confidence: 99%

Fate and Biotransformation of Metal and Metalloid Species in Biological Wastewater Treatment Processes

Stasinakis

Thomaidis

2010

Critical Reviews in Environmental Science and Technology

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Suspended and attached growth wastewater treatment processes are widely used for the removal of biodegradable organic constituents and nutrients from wastewater. The frequent detection of toxic metals and metalloids in wastewater contributed to the publishing of numerous papers in the past, investigating their presence, toxicity and behavior in biological wastewater treatment systems (BWTS). In most of these studies, data were referred to total element concentration. However, nowadays it is generally accepted that toxicological and physicochemical properties are differentiated according to elemental speciation. The literature review revealed that there are enough studies investigating chromium species presence, toxicity, fate and biotransformation in BWTS, whereas there are fewer data for organotin compounds. Even less studies exist for arsenic, mercury and selenium species. Most of the results are referred to the activated sludge process. The biotransformation mechanisms are element-dependent. The reduction of Cr(VI) to Cr(III), the sequential debutylation of tributyltin and triphenyltin to inorganic tin, the oxidation of As(III) to As(V) and their methylation to organoarsenicals have been observed. Despite the gaps in the literature, these preliminary, in many cases, results indicate that biological wastewater treatment processes could be used in the future for the detoxification of metal-and metalloid-laden wastewater, allowing the reuse of wastewater and sludge.

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“…A pilot scale activated sludge wastewater treatment plant was constructed as described in detail by Pavlogeorgatos [12][13][14][15][16] (Figure 1). The operational parameters of the pilot plant are presented in Table 1.…”

Section: Experimental Setup and Samplingmentioning

confidence: 99%

Determination of methyl mercury in a pilot-scale activated sludge wastewater treatment plant

2013

Global NEST Journal

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The methylation of mercury has been investigated and documented mainly in sediments, fish and microorganisms, while limited number of relevant studies is available for wastewater. The procedure of mercury methylation can occur via biological pathway (by microorganisms) and via chemical or photochemical reactions.Methylation of mercury occurs mainly under anaerobic conditions, but some studies have shown its existence also under aerobic conditions. The resulting concentration of methyl mercury, which is a highly toxic compound, depends on the specific rates of methylation/demethylation of mercury. The factors affecting these procedures are the availability of inorganic mercury, pH, organic matter concentration, microbial activity, redox potential and temperature. Bacteria which can methylate mercury are often present in wastewater, and, therefore, the formation of methyl mercury during wastewater treatment is possible.The objective of the present investigation was the determination of methyl mercury in a pilotscale activated sludge wastewater treatment plant supplied with synthetic wastewater enriched with mercury. For this purpose, a Liquid-Liquid Extraction / Simultaneous Derivatization -GC/MS method was developed and applied for the analysis of samples from the aeration tank, from the treatment plant effluent and from the sludge.Methyl mercury was not detected in the samples (detection limit 0.07 µg l -1 ), leading to the conclusion that mercury is not methylated under the particular experimental conditions of the pilot-scale water treatment plant.

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Examination of mercury's effects during the process of the activated sludge

Cited by 5 publications

References 6 publications

Effect of mercury-contaminated wastewater on activated sludge suspended solids size distribution

Effect of mercury-contaminated wastewater on activated sludge suspended solids size distribution

Fate and Biotransformation of Metal and Metalloid Species in Biological Wastewater Treatment Processes

Determination of methyl mercury in a pilot-scale activated sludge wastewater treatment plant

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