Persistence of Nitrite-Oxidizing Bacteria in Entrapped Cell-Based Partial Nitrifying Reactor Treating Ammonia-Rich Wastewater

A phosphorylated-polyvinyl alcohol (PPVA) entrapped cell-based reactor was employed to promote partial nitrification for ammonia-rich wastewater treatment. High partial nitrification (66% of nitrite accumulation in average) was achieved along the 165 days of operation indicating that the majority of nitrite-oxidizing bacteria (NOB) activity was suppressed probably as a result of low oxygen environment created within the PPVA gel matrix. However, some portion of nitrate (5-17.6% of the influent ammonia) always appeared in the reactor throughout the operation period. Next-generation sequencing and clone library techniques revealed that NOB with different substrate affinities including Nitrobacter, Nitrospira lineage I and II existed within the gel matrix. The finding speculates that substrate gradient-like microenvironment within the gel matrix probably serves the different physiological groups of NOB to maintain their cells and activities in the reactor. Therefore, instead of using low oxygen environment in gel matrix as a sole control strategy, an additional strategy like promoting free ammonia inhibition in reactor is also needed to affirm the stability of long-term partial nitrificatio

Feasibility Study of Water Reclamation Projects in Industrial Parks Incorporating Environmental Benefits: A Case Study in Chonburi, Thailand

Financial feasibility is usually a concern in water reclamation projects. Aside from internal benefits, water reclamation in industrial parks delivers health and environmental benefits not normally considered in cost–benefit analyses (CBA). This study investigated the influence of environmental benefits on the feasibility of water reclamation projects with flow rate scenarios in accordance with industrial parks in Chonburi, Thailand. CBAs of water reclamation plants for industrial water supply, consisting of ultrafiltration (UF) and reverse osmosis (RO), with flow rates of 5200, 10,000, 15,000, and 25,000 m3/day and discount rates of 3%, 5%, 7%, 9% and 11% were conducted. Considering only the direct costs and benefits, none of the projects were financially feasible. However, when the environmental benefits were included, the projects became profitable in all cases except those with a flow rate of 5200 m3/day and discount rates of 5%, 7%, 9%, and 11% and those with flow rates of 10,000 and 25,000 m3/day and an 11% discount rate. Further, CBAs of water reclamation projects in industrial parks for irrigation were conducted with post-treatment processes consisting of sand filtration and chlorine disinfection for flow rates of 240, 480, 2400, 3600, and 4800 m3/day. The projects are profitable, regardless of environmental benefits

Feasibility Study of Water Reclamation Projects in Industrial Parks Incorporating Environmental Benefits: A Case Study in Chonburi, Thailand

Financial feasibility is usually a concern in water reclamation projects. Aside from internal benefits, water reclamation in industrial parks delivers health and environmental benefits not normally considered in cost–benefit analyses (CBA). This study investigated the influence of environmental benefits on the feasibility of water reclamation projects with flow rate scenarios in accordance with industrial parks in Chonburi, Thailand. CBAs of water reclamation plants for industrial water supply, consisting of ultrafiltration (UF) and reverse osmosis (RO), with flow rates of 5200, 10,000, 15,000, and 25,000 m3/day and discount rates of 3%, 5%, 7%, 9% and 11% were conducted. Considering only the direct costs and benefits, none of the projects were financially feasible. However, when the environmental benefits were included, the projects became profitable in all cases except those with a flow rate of 5200 m3/day and discount rates of 5%, 7%, 9%, and 11% and those with flow rates of 10,000 and 25,000 m3/day and an 11% discount rate. Further, CBAs of water reclamation projects in industrial parks for irrigation were conducted with post-treatment processes consisting of sand filtration and chlorine disinfection for flow rates of 240, 480, 2400, 3600, and 4800 m3/day. The projects are profitable, regardless of environmental benefits

Survey of Microbial Diversity in Flood Areas during Thailand 2011 Flood Crisis Using High-Throughput Tagged Amplicon Pyrosequencing.

The Thailand flood crisis in 2011 was one of the largest recorded floods in modern history, causing enormous damage to the economy and ecological habitats of the country. In this study, bacterial and fungal diversity in sediments and waters collected from ten flood areas in Bangkok and its suburbs, covering residential and agricultural areas, were analyzed using high-throughput 454 pyrosequencing of 16S rRNA gene and internal transcribed spacer sequences. Analysis of microbial community showed differences in taxa distribution in water and sediment with variations in the diversity of saprophytic microbes and sulfate/nitrate reducers among sampling locations, suggesting differences in microbial activity in the habitats. Overall, Proteobacteria represented a major bacterial group in waters, while this group co-existed with Firmicutes, Bacteroidetes, and Actinobacteria in sediments. Anaeromyxobacter, Steroidobacter, and Geobacter were the dominant bacterial genera in sediments, while Sulfuricurvum, Thiovirga, and Hydrogenophaga predominated in waters. For fungi in sediments, Ascomycota, Glomeromycota, and Basidiomycota, particularly in genera Philipsia, Rozella, and Acaulospora, were most frequently detected. Chytridiomycota and Ascomycota were the major fungal phyla, and Rhizophlyctis and Mortierella were the most frequently detected fungal genera in water. Diversity of sulfate-reducing bacteria, related to odor problems, was further investigated using analysis of the dsrB gene which indicated the presence of sulfate-reducing bacteria of families Desulfobacteraceae, Desulfobulbaceae, Syntrobacteraceae, and Desulfoarculaceae in the flood sediments. The work provides an insight into the diversity and function of microbes related to biological processes in flood areas

Comparison of fungal diversity in sediment and water.

<p>Percent relative abundance of fungal phyla based on ITS sequence abundance are shown. Left and right bars represent relative abundance collected from sediment and water, respectively.</p

Comparative distribution of fungal diversity in sediment and water.

<p>(A) Principal component analysis (PCA) based on percent relative abundance of fungal taxa at genus level in sediment (orange) and water (blue). (B) Bar chart with extended error bar for pair-wise comparisons of fungal genera between sediment (orange) and water (blue) samples.</p

Map of sample collection sites.

<p>The sampling areas are in Bangkok, Pathumthani, Nonthaburi, and Nakornpathom provinces.</p