Study of biofilm associated bacteria on polyvinyl chloride, stainless steel and glass surfaces in a model cooling tower system with different microbiological methods

Year 2012, Volume: 71 Issue: 1, 63 - 76, 05.10.2012

Nazmiye Ozlem Sanli Yurudu

Abstract

Cooling towers are an integral part of large range of industrial processes. The conditions of cooling water systems provide an ideal environment for microbial growth and biofilm formation. Microorganisms which enter via makeup water or air to the system form a biofilm layer on the inside surfaces of cooling tower which contain water and limited nutrients. Biofilm formation in cooling tower systems is undesirable for operational and public health reasons. Thus, microbial load should be monitored and kept under control. In this study, bulk water and biofilm associated microbial load were analyzed in terms of heterotrophic plate count (HPC), epifluorescence microscopy, carbohydrate quantity, total and free ATP concentration and compared material dependence. Kruskal-Wallis statistical analysis revealed that there were not significant differences between the tested slide materials according to HPC, DAPI-CTC staining, and ATP measurement. The ATP measurement together with fluorescence staining reflected the changes in the biofilms more distinctly than the HPC.

Keywords

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Model bir soğutma kulesi sisteminde polivinil klorid, paslanmaz çelik ve cam yüzeyler üzerindeki biyofilmle ilişkili bakterilerin farklı mikrobiyolojik yöntemlerle incelenmesi

Abstract

Soğutma kuleleri birçok endüstriyel sürecin parçasıdır. Soğutma suyu sistemindeki koşullar mikrobiyal gelişim ve biyofilm oluşumu için ideal bir ortam sağlar. Tamamlama suyu veya havadan sisteme giren mikroorganizmalar su ve kısıtlı besin içeren soğutma kulesinin iç yüzeylerinde biyofilm tabakası oluştururlar. Soğutma kulesi sistemlerinde biyofilm oluşumu, sistemin çalışma koşulları ve kamu sağlığı nedenleri ile istenmeyen bir durumdur. Bu nedenle mikrobiyal yük takip edilmeli ve kontrol altında tutulmalıdır. Çalışmada su ve biyofilmle ilişkili mikrobiyal yük heterotrofik plak sayım, epifloresan mikroskobi, karbonhidrat miktarı, toplam ve serbest ATP konsantrasyonu açısından incelenmiş ve materyaller kıyaslanmıştır. Kruskal-Wallis istatistik analizine göre test edilen malzemeler arasında heterotrofik plak sayım, epifloresan mikroskobi, toplam ve serbest ATP konsantrasyonu açısından önemli bir fark tespit edilmemiştir. Floresan boyama ve ATP ölçümü tekniklerinin birlikte kullanımı biyofilmdeki değişiklikleri heterotrofik plak sayımdan daha net yansıtmaktadır

Keywords

Biyofilm, soğutma kulesi, paslanmaz çelik, ATP, DAPI-CTC boyama

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