Population Dynamics In Two-stage Anaerobic Digester Treating Solid Wastes

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2010Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2010Günümüzde ortaya çıkan doğal kaynakların tükenmesi ve enerji yetersizliği gibi global problemler, bilimsel araştırmaların yönünü çevrel kirliliğini de önleyecek sürdürülebilir tekniklere yöneltmiştir. Bu bağlamda, etkili bir enerji geri kazanımı için, proses mikrobiyolojisinin ve dinamiklerinin yeterli şekilde anlaşılması anahtar bir rol üstlenmektedir. Bu çalışmanın amacı, iki farklı organik atığın anaerobik arıtımı sonucu oluşan kimyasal gradyanların ve populasyon dinamiklerinin izlenmesi, bunların sistem performansı ve mikrobiyal topluluk yapısına göre karşılaştırılmasıdır. Arke ve bakteri populasyon dinamikleri, çevresel değişkenlerin sonucundaki mikrobiyal izlerin değerlendirilmesi ve organik atık parçalanmasıyla ilişkili organizmaların tanımlanmasını sağlamak için asitleştirici (fermentör) ve çürütücü(metan reaktörü) şeklinde ayrılan iki kademeli anaerobik sistemde incelenmiştir. Örnekler, yemekhane ile sebze atıklarıyla beslenen ve farklı işletme koşullarında işletilen (pH, substrat ve yükleme oranı) reaktörlerden aylık olarak alınmıştır. Mikrobiyal çeşitlilik ve mikrobiyal komposizyondaki değişimler 16S rRNA geni tabanlı klonlama ve sekanslama ile DGGE moleküler mikrobiyolojik teknikler kullanılarak incelenmiştir. Her bir reaktörden alınan numunelerden, genel primerler kullanılarak arke ve bakteri sınıflarının klon kütüphanesi oluşturulmuştur. Yemekhane atıkları için 84’ü fermentörden, 61’i çürütücüden olmak üzere toplam 145 bakteri klonu 7 kütüphaneden, toplam 65 arke klonuda 4 farklı klon kütüphanesinden, sebze atıkları için 96 bakteri klonu asitleştiriciden(fermentör), 51’I çürütücüden, toplamda 145 bakteri klonu 6 farklı kütüphaneden, toplamda 25 arke klonu da 4 farklı kütüphaneden sekanslanmıştır. Bu sayılar anaerobik çamurdaki mikroorganizma türlerinin çeşitlilik gösterdiğini ve her bir substrat için reaktörlerdeki açık farklılıkları ortaya koymaktadır. DGGE ve klon analizleri arke tür yapısının pH ve uçucu yağ asit (UYA) konsantrasyonuyla yüksek korelasyona sahip olduğunu, bakteri türleri içinde pH’ın etkili olduğunu göstermektedir. Yemekhane atıklarıyla yapılan çalışmada, fermentörün 30 günlük işletilmesi sonunda Lactobacillus türü dominant hale gelmiş, çürütücüde ise Thermotogae, Firmicutes, Synergistetes, Synergistetes, Bacteroidetes filumlarının baskın olduğu görülmüştür. Fermentörde baskın olan arke türü Methanobacteriales filumundan Methanobrevibacter acididurans’tır, Methanomicrobiales filumundan Methanofollis liminatans’ta reaktör çeşitliliğinde yer almaktadır. Çürütücüde ilk olarak görülen Methanosarcinaceae türünün baskınlığı 3 ay işletmeden sonra Methanosaetaceae türüyle değişmiştir. Sebze atıklarıyla yapılan çalışmada DGGE bant verilerine göre fermentördeki baskın bakteri populasyonu Lactobacillaceae, Veillonellaceae ve Prevotellaceae türleridir, çürütücüde ise Desulfobacteraceae ve Syntrophaceae türleri baskındır. Prosese girmemiş atıkta mikro-anoksik boşluklar sebebi ile Methanobacteriaceae ve Methanosarcinaceae türlerine rastlanmıştır. Fermentör çamurunda Methanobacteriaceae dominant olup, çürütücü çamurunda ise Methanobacteria ve Methanomicrobia filumu ve az miktarda Methanococci filumuna rastlanmıştır. Farklı subtratlarla farklı fiziko-kimyasal şartlarda işletilmesine rağmen, birbirine benzer arıtma preformansları elde edilmiş olan çürütücü reaktöründe mikrobiyal topluluk yapısı önemli ölçüde farklı bulunmuştur. Söz konusu mikrobiyal populasyon farklılığı,, enerji geri kazanım sürecini etkileyebilmektedir.Today, global problems associated with depleted natural sources and energy insecurity, changes research efforts toward sustainable techniques to eliminate environmental pollution. For achieving an effective anaerobic process for energy recovery, adequate understanding of process microbiology and dynamics are playing a key-role. The objective of this study was to monitor the chemical gradients and population dynamics that occur during anaerobic treatment of two different organic wastes, and compare them according to system performance and microbial community structure. Archaeal and bacterial population dynamics were examined in two-stage anaerobic digester system that was separated as acidification and digestion, to identify those organisms associated with organic waste degradation and to assess patterns in microbial response across environmental variables. Samples were taken monthly from each reactors that were operated under different conditions (pH, substrate, and loading rate) and were fed with dinner hall and vegetable hall wastes. The microbial diversity and changes in the microbial composition were analyzed by molecular microbiological techniques based on the 16S rRNA gene: cloning and sequencing, denaturing gradient gel electrophoresis. From each reactor, clone libraries were constructed using universal primers for either the class Archaea and Bacteria. Sequencing of 145 bacterial clones that 84 in fermenter, 61 in digester from 7 libraries and 65 archaeal clones from 4 libraries for dinner hall wastes, 147 bacterial clones that 96 in fermenter, 51 in digester from 6 libraries and 25 archaeal clones from 4 libraries revealed a diverse anaerobic sludge community and distinct differences among reactors for both substrates. The DGGE and clone analysis indicated that the archaeal community structure was closely correlated with the volatile fatty acid (VFA) concentration and pH, while the bacterial population was impacted by pH. Members of the class Lactobacillus species were dominant after 30 days operation in fermenter and Thermotogae, Firmicutes, Synergistetes, Synergistetes, Bacteroidetes phylum’s in digester of dinner hall waste’s reactors. The archaeal community of fermenter consisted mainly of Methanobrevibacter acididurans sp. from Methanobacteriales phylum and Methanofollis liminatans from Methanomicrobiales phylum. Digester community were consisted mainly of Methanosarcinaceae sp. then changed to Methanosaetaceae sp. after 3-month operation. Bacteria corresponding to prominent DGGE bands in vegetable hall reactor’s sludge were belong to the class Lactobacillaceae and Veillonellaceae, together with Prevotellaceae in fermenter, Desulfobacteraceae, Syntrophaceae class in digester. Raw substrate contains archaeal communities such as Methanobacteriaceae and Methanosarcinaceae that could be linked to micro-anoxic zones inside raw waste. Methanobacteriaceae sp. was also dominant in fermenter sludge, Methanobacteria and Methanomicrobia phylum and Methanococci in minor amounts in digester sludge were detected. Despite similar reactor performance with respect to chemical parameters in digester of different substrates, the underlying community structures were different, which may have an influence on energy recovery period.Yüksek LisansM.Sc

Microbial community structure and a core microbiome in biological rapid sand filters at Danish waterworks

Rapid sand filtration is a traditional and common technology for drinking water purification from groundwater. Despite its wide scale and long-term use, the diversity and characterization of microbial communities in these engineered systems have remained unexplored and their roles in removal performances yet to be discovered. In order to explore the microbial ecology of these systems, we conducted 16S rRNA gene (rDNA) based 454 pyrosequencing as a deep sequencing approach to 94 sample cores retrieved from 5 different waterworks including proper biological replication. This comprehensive sampling of replicate rapid sand filters across many waterworks together with high-throughput sequencing provides a first glimpse into the microbial communities in rapid sand filters and their potential roles in the treatment process

Metagenomic analysis of rapid gravity sand filter microbial communities suggests novel physiology of Nitrospira spp

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Internal Porosity of Mineral Coating Supports Microbial Activity in Rapid Sand Filters for Groundwater Treatment

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