Microbial load in bio-slurry from different biogas plants in Bangladesh

Abstract

Objective:The study was aimed to isolate, identify, and characterize common indicator bacteria, including Escherichia coli, Salmonella spp., and Staphylococcus spp. in manure and bio-slurry samples of different livestock farms and biogas plants of Bangladesh.Materials and Methods:A total of 114 samples of manure and bio-slurry were collected from different livestock farms and biogas plants in Bangladesh. The total viable count (TVC), E. coli, Salmonella spp., and Staphylococcus spp. counts were determined by the spread plate technique method. Isolation and identification were performed by colony characteristics, staining, biochemical tests, and, finally, by using PCR. Antibiotic susceptibility test of the isolated bacteria was tested against commonly used antibiotics by using the disk diffusion method.Results:The mean TVC, E. coli, Salmonella spp., and Staphylococcus spp. counts were ranged from 8.19–10.75, 5.2–6.96, 5.81–6.87, 5.68–7.68 in manure samples and 7.26–8.65, 3.82–5.2, 4–5.54, 3.14–5.9 log cfu/gm in bio-slurry, respectively. In anaerobic digester after 30 days digestion, the presence of E. coli, Salmonella spp., and Staphylococcus spp. varied from 0–5.11, 0–4.84, and 0–5.59 log cfu/gm at 25°C, 27°C, 29°C, and 45°C temperature. Above-mentioned bacteria were absent in bio-slurry collected from anaerobic digester after 60 days digestion at environmental temperature. Bacterial counts were reduced significantly in both household slurry pits and experimental anaerobic digester. Antibiotic susceptibility results revealed that multidrug-resistant indicator bacteria were present in the bio-slurry samples.Conclusion:Our findings conclude that the microbial load after treatment of animal manure via anaerobic digestion (Biogas plant) was grossly reduced and the reduction of bacterial pathogen depends on the duration and temperature of digestion.

Environmental and molecular approach to dye industry waste degradation by the ascomycete fungus Nectriella pironii

“…Due to the potential risk of water and soil contamination by landfill leachate, the chemical composition of the leachate, groundwater (with 9 piezometer applications), cleaned plant wastewater and water of the Bzura River are monitored by The Voivodeship Inspectorate of Environmental Protection in Łódź 19 , 20 . The results of the leachate study carried out in autumn 2020 are presented in Table 1 .…”

“…Additionally, during some chemical methods, e.g., oxidation or ozonation, hazardous intermediates are formed 19 . Methods based on biological degradation are more environmentally friendly and less expensive and can be an encouraging alternative for toxic compound elimination in polluted areas 18 , 20 – 22 . However, dyeing processes involve not only a variety of colorants but also different alkalis, organic and inorganic salts, acids and heavy metals; hence, it is essential to seek microorganisms that not only decolorize dyes but also retain their properties in conditions unfavorable for the metabolic activity of most microorganisms.…”

Performance evaluation of prefabricated polyvinyl chloride floating dome type anaerobic biogas digester of different feeding intervals using animal waste

“…The results of bacterial reduction were closely related to the previous study. Islam et al 19 found that the log reduction of TVC, E. coli and Salmonella spp. were 1.89, 1.45 and 1.64 from manure sample to bio-slurry samples.…”

“…Undigested animal waste like cow dung, poultry manure, household waste and agricultural waste contains many diseases causing pathogenic microorganisms that have serious health problems to humans and the environment. 19 The bacterial pathogens, including Escherichia coli, Salmonella, Listeria monocytogenes, Mycobacterium avium subsp. Paratuberculosis, Clostridium spp., Bacillus spp., Campylobacter, Yersinia enterocolitic, Staphylococcus and Streptococci are isolated from the manure and bio-slurry and interestingly, most of the isolated bacteria have public health significance.…”

Chemical and Microbiological Analysis of Organic Manure of Nisargruna Biogas Plant and its Applications as Carrier Materials for Biofertilizers

“…The results obtained in the present study are in agreement with the report cited by Sturmer et al, 21 that showed absence of E.coli, Salmonella, Listeria and Campylobacter in the digestate. In another study, Islam et al, 23 reported the presence of E. coli, Salmonella and Staphylococcus species in the initial stages of manure production. After 30 days, the number of these bacteria was reduced and found to be absent when analyzed after 60 days.…”