Baseline Dataset on Bacterial Counts, Morphotypes and Gram Staining from Urban Wastewater Treatment Plants of Gujarat, Western India
Description
This dataset contains culture-based enumeration and phenotypic characterization of bacteria isolated from five municipal sewage treatment plants (STPs) in Gujarat, western India—two located in Vadodara District and three in Anand District. Water samples were collected from three major treatment stages at each STP: (i) Influent (raw incoming sewage), (ii) Aeration tank (biological treatment zone), and (iii) Final effluent (post-chlorination discharge point). The primary goal was to analyze variations in bacterial load and morphology throughout the treatment process, with a specific focus on the impact of chlorination. Sterile 50 mL centrifuge tubes were autoclaved and used for sampling. Samples were immediately transported to the laboratory in ice-packed containers to maintain bacterial viability. Serial dilutions up to 10⁻⁸ were prepared using 0.8% saline and 100 µL from each dilution was plated on nutrient agar using the spread plate method. After 24 hours of incubation at 37°C, colony-forming units per milliliter (CFU/mL) were calculated for each sample. Isolated colonies were further sub-cultured and studied for colony morphology (color, size, margin, elevation, and surface characteristics) and Gram reaction via standard Gram staining procedures. This dataset includes: CFU/mL data for each treatment stage across all five STPs; Morphological traits for each distinct bacterial colony type; Gram reaction results (positive/negative); Graphical representation of bacterial reduction across treatment stages; Comparative analysis between STPs of Vadodara and Anand Districts; and Correlation plots showing relationships between treatment efficiency and bacterial type distribution. This dataset provides important baseline information about microbial diversity, abundance, and disinfection response in domestic sewage environments. It is highly relevant for researchers working on environmental microbiology, wastewater treatment, water quality assessment, and antimicrobial resistance (AMR) tracking. These data may also assist in selecting target organisms for genomic or transcriptomic studies in future investigations focused on AMR development due to disinfection stress. The data are presented in structured spreadsheets with accompanying legends and metadata files. Files are organized by District and STP with all associated morphological and Gram-staining observations. Visuals such as bar plots and correlation heatmaps are included in PNG format. This resource can serve as a baseline for future comparative studies and aid in decision-making related to wastewater treatment upgrades or AMR mitigation efforts in STPs at global scale.
Files
Steps to reproduce
Aeration tank; Antimicrobial resistance (AMR); Bacteria; Bacterial enumeration; CFU/mL; Chlorination; Colony Forming Unit; Colony morphology; Effluent; Environmental microbiology; Enumeration; Gujarat (Western India) STPs; Gram staining; Influent; Isolation; Microbiology; Municipal wastewater; Sewage microbiology; Waterborne bacteria; Wastewater Treatment Plant