Microbial Assessment Research Articles

Enhancing the quality and shelf life of chevon using orange peel extract

The experiment was conducted to find out the effect of different levels of orange peel extract as a natural antioxidant and antimicrobial agent on fresh and preserved chevon. For this purpose, fresh chevon samples were divided into four treatment groups. These were treated as T0 (control group 0% orange peel extract), T1 (0.2% orange peel extract), T2 (0.3% orange peel extract) and T3 (0.4% orange peel extract) respectively. Sensory tests (color, flavor, tenderness, juiciness and overall acceptability), proximate components (DM, CP, EE and Ash), physicochemical quality (Raw meat pH, cooking loss), biochemical properties (POV, FFA and TBARS) and microbial assessment (TVC, TCC and TYMC) examination were determined in order to evaluate the effect of orange peel extract as natural antioxidant and antimicrobial agent for maintaining chevon qualities and the shelf-life of chevon for 0, 5, 10 and 15 days of storage period under refrigeration temperature. Among the four treatments T3 (0.4% orange peel extract) was the best in terms of nutrient quality, physicochemical properties, biochemical analysis and microbial assessment. Therefore, it is concluded that 0.4% orange peel extract may be used up to 15 days for chevon preservation.

Impact of dietary inflammatory index on gingival health.

Periodontal disease is a biofilm-dependent chronic inflammatory condition triggered by a host response. Several factors impact systemic inflammation and could lead to changes in disease pathogenesis. Recently, studies have assessed the influence of nutritional patterns on the development of periodontitis. In the present cross-sectional study, we evaluated the dietary inflammatory profile on periodontal conditions, focusing on clinical, subgingival microbial, and cytokine assessment of individuals with periodontal health or gingivitis. One hundred patients with periodontal health or gingivitis were included. Plaque index (PI), Bleeding on probing (BoP), the probing depth (PD), and the clinical attachment level (CAL) for each patient were assessed. Nutritional data and the Dietary Inflammatory Index (DII) were recorded by two 24-h food recalls on non-consecutive days. Biofilm and gingival crevicular fluid (GCF) to assess the microbiome profile and inflammatory biomarkers were collected. Multiple regressions focused on the DII, age, and sex as predictors of periodontal conditions were done. Age and moderate DII scores increased the risk of gingivitis by 1.64 and 3.94 times, respectively. Males with an elevated DII score had 27.15 times higher odds of being diagnosed with gingivitis and BoP (β=6.54; p=0.03). Elderly patients with a moderate or high DII score were less prone to gingivitis and increased BoP (p<0.04) compared with younger subjects. Considering the DII, there were no differences in microbial alpha and beta diversity; however, distinct species abundance and a higher concentration of monocyte-chemoattractant protein-1 and interleukin 33 were seen in patients with a higher DII. A pro-inflammatory diet significantly contributes to periodontal inflammation, modulating inflammatory biomarkers and affecting the subgingival microbial community in healthy individuals.

Bacteriological Evaluation of Indoor Air Quality in Some Selected Units at the University of Cape Coast Hospital in Ghana

A hospital is an environment solely for diagnosing and treating patients. Contemporary research, however, reveals the possibility of users contracting diseases due to many factors, such as poor air quality. This research, therefore, delves into the critical indoor air quality assessment domain, focusing on selected units within the University of Cape Coast Hospital, Ghana. The study’s primary objective was to conduct a comprehensive microbial assessment of indoor air quality in eight different units (emergency room, operating theater, out-patient department, consulting rooms, laboratory, male ward, female ward, and ear, nose, and throat unit) of the hospital, shedding light on potential airborne bacteria present. Indoor and outdoor air were sampled using Koch’s sedimentation method. Colony forming units per cubic meter of air (cfu/m3) were determined with the Omeliansky formula. The bacteriological load within the units revealed that the out-patient department had the highest bacterial concentration (139.2±60.32×102 cfu/m3), immediately followed by Outdoor (135.1±43.63×102 cfu/m3), whereas ear, nose, and throat unit recorded the least concentration (0.4±0.57×102 cfu/m3). The remaining units range between 135.1±43.63×102 cfu/m3 and 0.4±0.57×102 cfu/m3. The morphological characteristics of the seven observed bacterial isolates (GSB 1-7) showed the presence of two cocci and five rods. Isolates 1 and 4 had a rhizoid form, isolates 2,3, and 5 had a circular form, while isolates 6 and 7 had filamentous forms. All isolates showed positive gram tests, and endospores were detected in isolates 1, 4, and 6. Bacterial isolates were identified as Bacillus mycoides, Micrococcus luteus, Staphylococcus epidermidis, Bacillus circulans, Staphylococcus saprophyticus, Bacillus subtilis, and Micrococcus sp. These outcomes indicate bacterial contaminations in the indoor environment, likely to pose a significant risk to patients, workers, and visitor’s safety. Therefore, rigorous monitoring and mitigation strategies are essential to ensure a safer environment in healthcare settings.

Microbial Quality Assessment of Fresh Sugarcane Juice in Retail Shops Inside Kathmandu Valley

This study aims to assess the microbial quality of fresh sugarcane juice sold in retail shops inside Kathmandu Valley, as there is limited information available on the safety of popular fresh juices like sugarcane juice, which can cause food-borne illnesses when improperly prepared, despite the known health benefits of consuming fresh fruits juices. Sixty fresh sugar cane juice samples were collected from selected thirteen areas inside Kathmandu Valley. Out of 60 samples, 42 samples were contaminated with bacteria. The quality of each sample was assessed by total plate count, total coliform count, yeast and mold count, and isolation of pathogenic bacteria. The isolated bacteria were identified based on biochemical characteristics. The pH of collected samples ranged from 4.33 to 6.34, acidity from 0.01% to 0.09%, and total soluble solids from 13 to 21⁰Brix. The mean bacterial count was 5.26 log10 CFU/ml, the coliform count was 4.67 log10 CFU/ml, and the yeast mold count was 4.94 log10 CFU/ml. E. coli was present in 38.1%, Citrobacter freundii in 47.6%, and Salmonella species in 14.3% of the total sample. Vibrio cholerae was not detected. Gentamicin, Ciprofloxacin, and Ofloxacin were effective, while Ampicillin was less effective. The study found that sugarcane juice samples from shops in Kathmandu Valley have high levels of contamination, including a high microbial load and slightly acidic pH with high total soluble solid values. The bacterial isolates exhibited varied degrees of antimicrobial susceptibilities and resistances, and the contamination was attributed to poor hygienic conditions during juice processing and handling, possibly due to the use of poor-quality water and a lack of training on food hygiene and safety. These findings suggest potential health hazards for consumers of fresh sugarcane juice.

To gate or not to gate: Revisiting drinking water microbial assessment through flow cytometry fingerprinting

Flow cytometry has been utilized for over a decade as a rapid and reproducible approach to assessing microbial quality of drinking water. However, the need for specialized expertise in gating—a fundamental strategy for distinguishing cell populations—introduces the potential for human error and obstructs the standardization of methods. This work conducts a comprehensive analysis of various gating approaches applied to flow cytometric scatter plots, using a dataset spanning a year. A sensitivity analysis is carried out to examine the impact of different gating strategies on final cell count results. The findings show that dynamic gating, which requires user intervention, is essential for the analysis of highly variable raw waters and distributed water. In contrast, static gating proved suitable for more stable water sources, interstage sample locations, and water presenting a particularly low cell count. Our conclusions suggest that cell count analysis should be supplemented with fluorescence fingerprinting to gain a more complete understanding of the variability in microbial populations within drinking water supplies. Establishing dynamic baselines for each water type in FCM monitoring studies is essential for choosing the correct gating strategy. FCM fingerprinting offers a dynamic approach to quantify treatment processes, enabling options for much better monitoring and control. This study offers new insights into the vagaries of various flow cytometry gating strategies, thereby substantially contributing to best practices in the water industry. The findings foster more efficient and reliable water analysis, improving of standardizing methods in microbial water quality assessment using FCM.

Microbial quality assessment of biltong produced and marketed in Lubumbashi, DR Congo

Objective: The aim of this study was to evaluate the hygienic quality of biltong produced locally and sold in Lubumbashi. Methods: Seventy-five biltong samples were taken randomly from five supermarkets in the city of Lubumbashi, at the rate of 15 samples per supermarket. Thus, the mesophilic aerobic flora (MAF), yeasts and molds, Staphylococcus aureus and Clostridium perfringens, were enumerated on these samples after a series of successive decimal dilutions and inoculations in selective media. Results: The results of microbiological analyzes revealed that levels of microbial contamination varied depending on the points of sale. MAF (2.34 ± 0.12 to 3.79 ± 0.17 x 106 CFU/g) as well as yeasts and molds (3.50 ± 0.17 to 4.25 ± 0.50 x 103 CFU/g) constituted the predominant flora of the biltong studied in five large supermarkets in the city of Lubumbashi with 100% of samples presenting levels of contamination above acceptable standards. S. aureus and C. perfringens were identified at low levels compared to acceptable standards, i.e. from 1.80 ± 0.07 to 3.79 ± 0.41 x 102 CFU/g and 15.33 ± 0.15 to 32, 33 ± 0.34 CFU/g, respectively. Conclusion: This study highlighted the exposure of the population of Lubumbashi to food poisoning through the consumption of locally produced biltong. Improving its hygienic quality involves reducing the total flora present on the meat, pathogenic germs and spoilage germs based on the initial microbiological quality of the meat used, improving personal hygiene agents assigned to production and improving the manufacturing process.

Microbial and chemical quality assessment of the small rivers entering the South Baltic. Part I: Case study on the watercourses in the Baltic Sea catchment area.

Microbial and chemical quality assessment of the small rivers entering the South Baltic. Part I: Case study on the watercourses in the Baltic Sea catchment area.

Microbial and chemical quality assessment of the small rivers entering the South Baltic. Part II: Case study on the watercourses in the Puck Bay catchment area

Microbial and chemical quality assessment of the small rivers entering the South Baltic. Part II: Case study on the watercourses in the Puck Bay catchment area

The application of different methods for indirect microbial development assessment in pilot scale drinking water biofilters

The application of different methods for indirect microbial development assessment in pilot scale drinking water biofilters

Microbial Assessment of Aprons Worn By Some Street Food Vendors In Awka South, Anambra State, Nigeria

Microbial Assessment of Aprons Worn By Some Street Food Vendors In Awka South, Anambra State, Nigeria

Microbial Food Safety Assessment of Organic Food and Feed: Notifications in the EU RASFF during 2020–2022. A Systematic Review

The presence of pathogenic bacteria in organic feed and food is a topic of current subject of study due to concerns that certain organic practices may heighten the risk of contamination and contribute to the spread of foodborne pathogens. The primary objective of this research is to analyze the main microbial contaminants exclusively associated with organic products, as reported in the literature. The search and selection of suitable studies were conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Databases consulted included Web of Science Core Collection, Medline (PudMed) database, and UE Rapid Alert System for Food and Feed (RASFF) database. Using the EU RASFF System, we have summarized the notifications in relation to these products during the last 3 years in Europe. Eligibility criteria were studies published in English between 2000 and 2022. All authors performed critical appraisal and independent data extraction. Analysis of RASFF notifications related to organic products over the period from January 2020 to October 2022 revealed that 61.7% of notifications were related to food, while only 38.2% were related to feed. Salmonella emerged as the predominant pathogen reported in both organic food and feed. Notably, only one food outbreak linked to Salmonella Enteritidis in eggs was reported during the study period. Among food commodities, seeds were the most frequently affected, with the highest percentage of food products with alerts originating from India. Regarding antimicrobial resistance, a noteworthy trend was observed, with a decrease in multidrug-resistant strains favoring organic production compared to conventional methods. In conclusion, this research aimed to investigate the presence of pathogenic bacteria in organic feed and food, considering the potential risk factors associated with organic practices and their implications for food safety.

Anitmicrobial Susceptibility to Microoranisms in Hematological Malignancies; A Need to Review Institutional Protocols

Abstract Introduction Febrile neutropenia is a medical emergency in patients with hematological malignancies. The severity of neutropenia and the duration of infection have an important implication on primary treatment outcome. Previously assessed institutional review revealed gram negative bacteria to be the most common microorganisms, and leading cause of febrile neutropenia. However, the predominance of gram positive bacteria had also increased in later past years [1]. In high risk patients, infections caused by multidrug resistant bacteria worsen treatment complications and thus at times empirical use of antibiotics like colomycin is required; otherwise the prognosis may be jeopardized [2]. Regular surveillance of local flora and susceptibility pattern of antimicrobial is must to elude the antimicrobial resistance. Objective The study was conducted to evaluate the prevalence of microorganisms and to observe the sensitivity pattern of antimicrobials as an institutional protocol to establish antimicrobial policies. Material and methods A cross sectional study was conducted at National Institute of blood diseases and bone marrow transplantation, PECHS campus from August 2021 - January 2022. Ethical approval was taken from research committee prior to the study and informed consent was taken from the patients. Febrile neutropenia was defined as a single reading of oral temperature of ≥38 °C on two or more occasions in 12 h in the presence of absolute neutrophil count of less than 1000cells/mm. Blood cultures were performed using the BACTEC blood culture system. Organisms were identified according to routine bacteriological procedures and disc diffusion method was used for interpreting antibiotic susceptibility. Data was analyzed by SPSS version 23.0. Frequencies and percentages were calculated for categorical variable and mean (standard deviation) was computed for quantitative variables. Association between categorical variables was observed using the chi-square test or Fisher’s exact test. P value of &amp;lt;0.05 was considered statistically significant. Results A total of 310 cultures taken from blood (37.4%), peripheral line (4.2%), hickman line (8.1%), red line (2.6%), pus (7.1%), sputum (9.7%) and urine (31%) samples were observed. Out of total 213 (69%) were found to be gram negative and 97 (31%) were gram positive. Gram negative were mostly reported in blood cultures 61 (20%) while gram positive was found in urine cultures 80 (26%). E.coli (40.8%) was the most prevalent among the gram negative microorganisms followed Klebsiella pneumonae (16.9%), Pseudomonas species (11.7%), Pseudomonas aeruginosa (11.3%), Burkholderia cepacia (7%), Enterobacter species (3.3%), Moraxella species (3.3%), Proteus mirabilis (2.8%), Salmonella typhi (1.4%), Acinetobacter species (0.9%) and Citrobacter species (0.5%). In gram negative organisms, Acinetobacter species, Burkholderia cepacia, Citrobacter species and Moraxella species were identified substantially which were not previously prevalent. In gram positive microorganisms Staphylococcus epidermidis (55.3%) was more prevalent, followed by Enterococcus species (19%), Micrococcus species (16%), Streptococcus species (6%), Staphylococcus aureus (3.7%), from which Micrococcus species was reported for first time. Sensitivity of meropenem, amikacin and colistin was higher in gram negative while the sensitivity of fosfomycin, and linezolid was found in gram positive isolates The association of sensitivity and resistance with gram negative and positive isolates was found statistically significant with amikacin, vancomycin, fosfomycin and ciprofloxacin (p=&amp;lt;0.05). Conclusion Gram negative isolates were found prevalent in our study. The sensitivity of meropenem, amikacin and colistin was high than other regimens in gram negative while the sensitivity of fosfomycin, and linezolid was found in gram positive isolates. Few emerging isolates were observed in the study as well. The regular review of microbial pattern and susceptibility evaluation is imminent for prevention of microbial resistance and assessment of institutional practices.

Detection of heavy metals using atomic absorption and emission spectroscopy in drinking water of Faisalabad, Pakistan: microbial safety and quality status assessment

Synthetic dyes from textile industries are designated as hazardous waste since they release heavy metals and dangerous contaminants in water that harm the environment and human health. The current study was aimed at investigating the heavy metals (Cd, Cu, Pb, Ni, Zn, Cr, and Mn) in drinking water in seven regions of Faisalabad, Pakistan, through atomic absorption spectroscopy (AAS) and optical emission spectroscopy (OES). The physicochemical quality of 86.36% of the water samples met the WHO standards in the targeted regions, while 13.64% failed to meet the criteria. The water quality index (WQI) of selected water samples was calculated by integrating 11 physicochemical parameters, and the results indicated fair quality, whereas Madina, Jinnah, and Lyallpur Town showed poor water quality with contamination of Mn > Ni > Pb. The order of contamination for heavy metals in groundwater was Ni > Cu > Zn > Cr > Pb > Mn > Cd. The total plate count (TPC) and total coliform count (TCC) were found within the permissible range of WHO guidelines. Hence, consuming groundwater in the research regions may not present major health risks due to ingested metal toxicity; however, levels of Mn, Ni, and Pb might pose risks.

Inhibition of microbial pathogens and toxicity assessment of noformicin synthesized by Psychrobacter faecalis: An endophyte of Averrhoa carambola

Plants are known to harbor endophytic microbes which primarily reside in tissues beneath the epidermal cells. The current study was focused on exploring the endophytic bacteria of Averrhoa carambola for antimicrobial activity. The metabolites of endophytic isolate VITPMJ7 were found to be effective in cross streak method (antagonistic activity) as it inhibited the growth of Bacillus cereus and Escherichia coli. Furthermore, the effective isolate was fermented and chloroform extract showed antibacterial activity in the well diffusion method against E. coli, B. cereus and Staphylococcus aureus. Chloroform extract was fractionated and the lead molecules were obtained using solid phase extraction column (SPE) and Ultra performance liquid chromatography (UPLC). The purified lead molecule that showed inhibitory effects was identified to be noformicin by GC-MS. The presence of various functional groups such as amine, thiol, alcohol, alkene, sulfoxide identified by FT-IR supported and confirmed the lead molecule to be noformicin. The isolate VITPMJ7 capable of producing the lead compound was identified to be Psychrobacter faecalis by 16 S rRNA gene sequencing. Toxicity assessment of the metabolites in seed germination assay with Vigna radiata, Vigna mungo and Cajanus cajan revealed the non-toxic nature of the compounds.

Microbial ecosystem assessment and hydrogen oxidation potential of newly discovered vent systems from the Central and South-East Indian Ridge.

In order to expand the knowledge of microbial ecosystems from deep-sea hydrothermal vent systems located on the Central and South-East Indian Ridge, we sampled hydrothermal fluids, massive sulfides, ambient water and sediments of six distinct vent fields. Most of these vent sites were only recently discovered in the course of the German exploration program for massive sulfide deposits and no previous studies of the respective microbial communities exist. Apart from typically vent-associated chemosynthetic members of the orders Campylobacterales, Mariprofundales, and Thiomicrospirales, high numbers of uncultured and unspecified Bacteria were identified via 16S rRNA gene analyses in hydrothermal fluid and massive sulfide samples. The sampled sediments however, were characterized by an overall lack of chemosynthetic Bacteria and the presence of high proportions of low abundant bacterial groups. The archaeal communities were generally less diverse and mostly dominated by members of Nitrosopumilales and Woesearchaeales, partly exhibiting high proportions of unassigned Archaea. Correlations with environmental parameters were primarily observed for sediment communities and for microbial species (associated with the nitrogen cycle) in samples from a recently identified vent field, which was geochemically distinct from all other sampled sites. Enrichment cultures of diffuse fluids demonstrated a great potential for hydrogen oxidation coupled to the reduction of various electron-acceptors with high abundances of Hydrogenovibrio and Sulfurimonas species. Overall, given the large number of currently uncultured and unspecified microorganisms identified in the vent communities, their respective metabolic traits, ecosystem functions and mediated biogeochemical processes have still to be resolved for estimating consequences of potential environmental disturbances by future mining activities.

Hygiene Knowledge, Attitudes, and Behaviors of Greek Undergraduate Students on Mobile Phones and Corresponding Devices’ Microbial Assessment

The purpose of this study was to investigate the knowledge, attitudes, and behaviors of Greek undergraduate students on hand hygiene and mobile phone hygiene, in relation to their mobile phones’ microbial load. An anonymous self-reported questionnaire was distributed among 100 students and swabs were taken from their devices for microbiological cultures and for an on-site bioluminescence microbial load assessment. Hand washing was considered the most effective personal protective behavior by the majority (89%), while spatial restrictions (40%) and forgetfulness (31%) were the main reasons for neglecting hand washing. Most students washed their hands 6–10 times/day (32%) for approximately 11–20 s (35%). Although most devices were cleaned/disinfected within the last week (28%), many were contaminated with Staphylococcus saprophyticus (84%), Staphylococcus aureus (13%), and Escherichia coli (39%), while 75% of the samples exceeded the “fail” threshold limit of the luminometer’s measurements. Moreover, statistically significant differences (p &lt; 0.05) were found between the devices’ microbial load and certain hand hygiene behaviors and preferences. The median cfu/cm2 of Escherichia coli was higher among first-year students of health sciences, while Staphylococcus aureus was more prevalent in females’ than in males’ mobile phones. It w therefore understood that undergraduate students’ knowledge, attitudes, and behaviors on hand hygiene and mobile phone hygiene are highly intertwined with the microbial load on their mobile phones.

Laser Doppler Flowmeter as a Periodontal Evaluation Method: A Clinical Pilot Study

Background and objectives: Periodontal disease, as an inflammatory pathology, induces hemodynamic changes that can be evaluated by different unbiased methods such as laser Doppler flowmetry. This clinical investigation assesses laser Doppler as a non-invasive procedure to monitor gingival vascularization and its potential relationship with the response to treatment of periodontal disease. Materials &amp; methods: 45 sites of white Spanish patients with active periodontitis undertake a complete periodontal analysis. This included periodontal pathogens identification along with the monitoring of the gingival margin microvascularization using a Doppler laser at the points exhibiting the most periodontal damage. All assessments were performed before and after periodontal combined treatment PCT (scaling, root planing, and antibiotic therapy prescription) (n = 45 sites). Results: Parameters of periodontal disease showed a positive correlation with pathogen levels. Blood flow readings decreased significantly after PCT (p &lt; 0,05), although this parameter was not statistically correlated with periodontal nor microbial assessments in a significant range. Conclusion: Laser Doppler is a complementary method of monitoring periodontal inflammation to traditional techniques of clinical periodontal evaluation. Further studies are necessary to determine its usefulness as a predictive method of periodontal disease evolution.

Microbial assessment of poultry farm biosecurity. Proceeding of The First International Avian Influenza Summit, University of Arkansas- October 16-17, 2023”

Biosecurity may be defined as protection from pathogens or disease. This may include the separation of the flock from living vectors or inanimate objects called fomites. While prevention of host-specific and zoonotic diseases is important, the commercial poultry industry is already preoccupied with the challenges of day-to-day operations. The purpose of this project was to illustrate how surfaces that may seem clean are heavily contaminated with microorganisms that may be responsible for human and avian diseases. We also evaluated three common intervention strategies, including disposable boot covers, foot baths, and tire disinfection. Poultry environmental samples were collected at the Texas A\&amp;M University Poultry Science Research Center, including fan shrouds, side air inlets, cool cell reservoirs, truck tires, truck floor mats, doorknobs, controller panels, a bioaerosol air sampler, and an impactor air sampler. A total of 30 samples were collected per sample type, which was homogenized, serially diluted, and spread plated onto agar media to culture total aerobes, Staphylococci, and coliform bacteria. 6.6 log10 colony-forming units cfu/cm2 of aerobic bacteria were found at the greatest concentration, followed by Staphylococci (5.6 log10 colony-forming units cfu/cm2) and coliforms (2 log10 colony-forming units cfu/cm2). This pattern was observed in most of the samples. Boot covers, foot baths, and tire disinfection were tested for efficacy. While disposable boot covers significantly reduced the number of aerobes, Staphylococci, and coliforms, as many as 300 microorganisms per cm2 still made it through to the inner boot cover. Disinfectants are commonly misused due to not properly clearing the surface prior to application or allowing the proper contact time. We found that while disinfection significantly reduced these indicator organisms, that reductions were only 10 to 100-fold, leaving many viable bacteria behind. Increased contact time from 3 seconds to 10 minutes resulted in significant reductions of aerobes and Staphylococcus. The tire wash data mirrored our foot bath data. Data was shared from previous laboratory and field trials. Less than 1% sterile poultry litter significantly reduced disinfectant efficacy across four product categories. Extended storage time of 30 weeks reduced product efficacy as well. We shared electron micrographs to illustrate how visually clean and smooth surfaces provide many hiding places for microbes, reducing disinfectant efficacy. While risk can never be reduced to zero, it may be reduced and controlled with good management practices. Cleaning and disinfection should follow a five-step process of dry cleaning, soap wash, rinse, drying, and finally disinfection. Labels should be read closely so that the product is used safely and effectively. While there are many viable products on the market, disinfecting a clean surface and following recommendations for contact time are very important to get the best results. Following best management practices such as reducing pest (insect/rodent) harborage and following your integrated pest management program will help reduce risk significantly.

Microbial pathogen profiling and water quality assessment of Jammu Himalayan springs

Microbial pathogen profiling and water quality assessment of Jammu Himalayan springs

Microbial assessment of foaming dynamics in full-scale WWTP anaerobic digesters

Research on foaming processes in wastewater treatment plants (WWTPs) anaerobic digesters is increasing since it is a common phenomenon that can seriously affect digesters performance and treatment cost. This paper presents data from a full-scale experience of foam monitoring and antifoam reagents dosing as well as microbial community structure. The association of foaming episodes with microbial population structure and operational parameters has improved understanding of foaming episodes and their causes. During this long-term study (273 days), two foaming episodes occurred in the anaerobic digesters under study. Microbial community analysis showed that the first foaming episode is correlated with the proliferation of ST-12K33 (midas_s_22), which could be related to variations in the hydraulic retention time, a decrease in inflow solids concentration, and a decrease in digesters total alkalinity. The second foaming episode coincide with a clear migration of Ca. Microthrix parvicella from the activated sludge (bulking episodes) to the anaerobic digesters and its capacity to metabolize substrate under anaerobic conditions. Laboratory experiments showed that an increase in anaerobic digestion temperature and sludge pre-treatments have a positive impact on foam biodegradability and, therefore, they could be used as foam mitigation strategies. Finally, a techno-economic analysis showed that foaming episodes had an over cost of about 250 € d−1 and dropped the WWTP energy self-sufficiency from 67 to 63 %.