Mark C. Meckes

The Ohio Environmental Protection Agency, Columbus, Ohio, United States

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Publications (5)5.16 Total impact

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    ABSTRACT: Blending is used in the wastewater industry to manage wet-weather events. Wastewater is treated through primary clarification, with flows in excess of the hydraulic capacity of the secondary system being directed to effluent disinfection. Before disinfection, the primary clarified effluent is "blended" with effluents that have been treated through the secondary system. The combined or "blended" effluents are then disinfected before being discharged to receiving waters. This study evaluated the effectiveness of chlorine to disinfect blended effluents. Experiments were conducted at bench-scale on primary and secondary effluents and three ratios of primary to secondary effluent (1:9, 3:7, and 5:5) from three publicly owned treatment works. Results from this study found that blending 10% or more primary effluent with secondary reduces the efficacy of chlorine disinfection, and coliphage survived chlorine disinfection better than bacterial indicator organisms. A simple empirical model for predicting indicator organism densities following chlorine disinfection was developed using data from this research.
    Water Environment Research 12/2010; 82(12):2373-9. · 1.13 Impact Factor
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    ABSTRACT: Heat stress has been used as a method of killing bacteria for many years, and is one approach promulgated by federal regulations to reduce pathogens in biosolids (40 CFR 503). However, recent studies have suggested that heat stressed organisms may be able to recover and re-grow after thermal treatment. The purpose of this study was to examine bacterial response to heat stress over time and to evaluate the ability of bacteria to recover and grow. Washed Cultures of E. coli were placed into bottles containing sterile buffer and buffer amended with 1% nutrient broth. The bottles were then subjected to heat at 55°C for 4, 6, and 24 hr. Contents of bottles were assayed over 10 days for growth on non-selective agar plates using the spread plate method. All plates were negative for growth immediately after heat stress, however in the samples heated for 4 hr. and 6 hr., recovery of E. coli was seen in buffer with nutrient broth after 24 hr. Recovery was also seen in buffer alone after 72 hr. Samples heated for 24 hr. were able to recover only in the presence of nutrients. Further work is being conducted using lower initial densities of E. coli to assess the difference between recovery and re-growth. A similar study was performed using a biosolids sample from a full-scale process that utilized pre-pasteurization followed by mesophilic digestion. Samples after digestion had no measurable densities of E. coli, however, after storage of the samples, detectable densities of E. coli were measured over a period of several days.
    Proceedings of the Water Environment Federation; 12/2009
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    ABSTRACT: Blending is a practice used in the waste water industry to deal with wet weather events where the hydraulic capacity of the treatment facility could be compromised. Blending consists of influent bypassing secondary treatment and then recombining or “blending” with disinfected secondary effluents before discharge into the receiving waters. Bench scale blending experiments were performed in this study with different ratios of primary to secondary waste water (5:5, 3:7, and 1:9). Blended effluents were disinfected at two concentrations and evaluated for microbiological indicators. Results indicate that disinfection of blended waste water is sufficient to reduce indicators such as fecal coliforms, however phages are more resistant and persist in samples with higher concentrations of primary effluent.
    Proceedings of the Water Environment Federation. 12/2007;
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    ABSTRACT: Waste wash waters from chicken egg-processing facilities can harbor high densities of bacteria, including salmonellae. For this study, we enumerated total coliforms, Escherichia coli, and Salmonella spp. in the egg wash waters of a large egg producer. We then determined how long these organisms would survive at temperatures of 5, 15, and 25 degrees C. We found that the fraction of salmonellae surviving over time at a given temperature was comparable to the fraction of indicator organisms that survived. We also found that the survival of these organisms varied with temperature, with 16, 8, and < 2 days being required for a 90% reduction of Salmonella in waste wash water held at 5, 15, and 25 degrees C, respectively. Finally, we noted that the response of laboratory-derived cultures to environmental stresses mimics the response of the indigenous microbial population, but individual cells within that population may survive for longer periods than laboratory-cultured strains.
    Journal of food protection 03/2003; 66(2):233-6. · 1.83 Impact Factor
  • Source
    M C Meckes, J A MacDonald
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    ABSTRACT: Current US regulations (40 CFR 503) for 'Class A' biosolids (treated sewage sludge) requires use of multiple-tube fermentation techniques for fecal coliform or multiple tube enrichment techniques for Salmonella spp. followed by isolation and biochemical and serologic confirmation. The technical difficulties and the time required to complete the procedure for enumeration of Salmonellae in biosolids and sludges has limited the use of this assay. This study was conducted to determine if a commercially available molecular probe system could be used to isolate and enumerate Salmonella spp. in biosolids or sludges in less time than cultural techniques with biochemical confirmation. Several types of treated and untreated municipal sludges were assayed for Salmonellae using a cultural technique with biochemical and serologic confirmation and a DNA probe diagnostic test kit. The results indicate that the molecular probe and the conventional fermentation tube technique yielded equivalent results. Interestingly, the probe technique yielded results within 52 h following initiation of sample analysis compared with the conventional fermentation tube technique with confirmation which required approx. 120 h. These results suggest that the molecular probe system used for this work may be used to determine the presence or absence of Salmonella spp. in biosolids within a relatively short time frame. The ease of using the DNA probe test kit, along with its ability to produce results in less than half the time of conventional culture techniques, suggests that this assay is useful for determining the presence or absence of Salmonellae in biosolids samples.
    Journal of Applied Microbiology 02/2003; 94(3):382-7. · 2.20 Impact Factor

Publication Stats

5 Citations
5.16 Total Impact Points

Institutions

  • 2003–2010
    • The Ohio Environmental Protection Agency
      Columbus, Ohio, United States
    • United States Environmental Protection Agency
      Cincinnati, Ohio, United States