Secondary effluent disinfection by peracetic acid (PAA): microrganism inactivation and regrowth, preliminary results

2003 ◽  
Vol 3 (4) ◽  
pp. 269-275 ◽  
Author(s):  
V. Mezzanotte ◽  
M. Antonelli ◽  
A. Azzellino ◽  
S. Citterio ◽  
C. Nurizzo
Keyword(s):  
Flow Cytometry ◽  
Peracetic Acid ◽  
Heterotrophic Bacteria ◽  
Pilot Scale ◽  
Secondary Effluent ◽  
Sample Collection ◽  
Sodium Thiosulphate ◽  
E Coli ◽  
Italian Law ◽  
Bacterial Removal

The paper summarises - in terms of bacterial removal and re-growth - the results of a pilot scale study performed on a continuous flow pilot plant, using peracetic acid (PAA) as disinfecting agent. Trials were carried out with increasing doses and contact times (6, 12, 18, 36, 42, 54 min). The paper reports data deriving from the only doses (15 and 25 mg L-1) which were able to ensure the respect of the limits for agricultural re-use, according to Italian law. Disinfection efficiency was comparable for E. coli, TC and FC, and lower for total heterotrophic bacteria (THB), and clearly grew with increasing Cát values. The effect of contact time was greater at the lower doses. Microbial counts, performed by both traditional methods and flow cytometry, immediately and 6 hours after the sample collection (PAA was previously inactivated by sodium thiosulphate and bovine catalase), showed that no appreciable re-growth took place after 6 hours for coliform group bacteria. THB formed a slightly lower number of colonies immediately after collection than after 6 hours. The slight variations observed after 6 hours were the result of the recovered ability of forming colonies and of the lysis of some of the residual bacteria, as it was shown by flow cytometry.

Peracetic acid for secondary effluent disinfection: a comprehensive performance assessment

2013 ◽  
Vol 68 (12) ◽  
pp. 2638-2644 ◽  
Author(s):  
M. Antonelli ◽  
A. Turolla ◽  
V. Mezzanotte ◽  
C. Nurizzo
Keyword(s):  
Peracetic Acid ◽  
Vibrio Fischeri ◽  
Pilot Scale ◽  
Selenastrum Capricornutum ◽  
Coliform Bacteria ◽  
Secondary Effluent ◽  
Indicator Organisms ◽  
E Coli ◽  
Comprehensive Performance

The paper is a review of previous research on secondary effluent disinfection by peracetic acid (PAA) integrated with new data about the effect of a preliminary flash-mixing step. The process was studied at bench and pilot scale to assess its performance for discharge in surface water and agricultural reuse (target microorganisms: Escherichia coli and faecal coliform bacteria). The purposes of the research were: (1) determining PAA decay and disinfection kinetics as a function of operating parameters, (2) evaluating PAA suitability as a disinfectant, (3) assessing long-term disinfection efficiency, (4) investigating disinfected effluent biological toxicity on some aquatic indicator organisms (Vibrio fischeri, Daphnia magna and Selenastrum capricornutum), (5) comparing PAA with conventional disinfectants (sodium hypochlorite, UV irradiation). PAA disinfection was capable of complying with Italian regulations on reuse (10 CFU/100 mL for E. coli) and was competitive with benchmarks. No regrowth phenomena were observed, as long as needed for agricultural reuse (29 h after disinfection), even at negligible concentrations of residual disinfectant. The toxic effect of PAA on the aquatic environment was due to the residual disinfectant in the water, rather than to chemical modification of the effluent.

Advanced wastewater disinfection technologies: short and long term efficiency

1998 ◽  
Vol 38 (12) ◽  
pp. 109-117 ◽  
Author(s):  
V. Lazarova ◽  
M. L. Janex ◽  
L. Fiksdal ◽  
C. Oberg ◽  
I. Barcina ◽  
...  
Keyword(s):  
Peracetic Acid ◽  
Contact Time ◽  
Pilot Scale ◽  
Coli Strain ◽  
Plate Count ◽  
Galactosidase Activity ◽  
Virus Removal ◽  
E Coli ◽  
Bacteriophage Ms2 ◽  
Short And Long Term

Advanced disinfection processes (peracetic acid, UV irradiation and ozonation) have been tested and evaluated through bench and pilot scale studies. 3 log removals of total coliforms, faecal coliforms and faecal streptococci were achieved by 10mg/L peracetic acid at a 10min contact time, by UV radiation at 35mW.s/cm2 and by ozone at 5mg/L for 10min contact time. Higher doses are required for virus removal by UV and PAA and especially for highly resistant viruses such as F-specific bacteriophage MS2. Ozonation has the advantage of having a strong effect on all types of bacteriophages and protozoa cysts even when low treatment doses and short contact times are applied. The results of this study demonstrated that evaluation of disinfection efficiency of ozone, UV and PAA depends on the criteria and methods employed. Standard method (plate count) results showed an important disinfection effect on culturability, while results from non-standard methods (respiratory activity and β-galactosidase activity assay) indicated less reduction of viable cells. Moreover, the results confirm that disinfectants act on bacteria in different ways. It has been clearly demonstrated that b-galactosidase activity is affected by PAA while UV treatment has no or very limited effect on the enzyme activity. Even without sunlight reactivation, bacterial regrowth in seawater was observed after disinfection of sewage effluents. This study also shows that the biodegradability of sewage effluent for an E coli strain was affected differently by the oxidative disinfectants ozone and PAA. Biodegradability should therefore be considered when evaluating the total disinfection efficiency.

Antimicrobial resistance of fecal indicators in disinfected wastewater

2011 ◽  
Vol 64 (12) ◽  
pp. 2352-2361 ◽  
Author(s):  
A. Luczkiewicz ◽  
K. Jankowska ◽  
R. Bray ◽  
E. Kulbat ◽  
B. Quant ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Treatment Plant ◽  
Tetracycline Resistance ◽  
Pilot Scale ◽  
Resistant Bacteria ◽  
Secondary Effluent ◽  
Fecal Indicators ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Operation Conditions

The main objective of the study was to assess the potential of three systems (UV irradiation, ozonation, and micro/ultrafiltration) operated in a pilot scale in removal of antimicrobial-resistant fecal bacteria from secondary effluent of the local wastewater treatment plant (700,000 population equivalent). The effectiveness of the processes was analysed using the removal ratio of fecal indicators (Escherichia coli and Enterococcus spp.). The susceptibility of fecal indicators to antimicrobial agents important in human therapy was examined. Resistance to nitrofurantoin and erythromycin was common among enterococci and followed by resistance to fluoroquinolones and tetracycline. Resistance to high-level aminoglycosides and glycopeptides was also observed. E. coli isolates were most frequently resistant to penicillins and tetracycline. The extended-spectrum beta-lactamase-producing E. coli was detected once, after ozonation. Substantial attention should be paid to the E. coli and enterococci resistant to three or more chemical classes of antimicrobials (MAR), which in general constituted up to 15 and 49% of the tested isolates, respectively. Although the applied methods were effective in elimination of fecal indicators (removal efficiency up to 99.99%), special attention has to be paid to the application of sufficient disinfection and operation conditions to avoid selection of antimicrobial resistant bacteria.

Secondary effluent reclamation: combination of pre-treatment and disinfection technologies

2008 ◽  
Vol 57 (12) ◽  
pp. 1963-1968 ◽  
Author(s):  
L. Alcalde ◽  
M. Folch ◽  
J. C. Tapias ◽  
F. Martínez ◽  
S. Enguídanos ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Chlorine Dioxide ◽  
Peracetic Acid ◽  
Additional Treatment ◽  
Secondary Effluent ◽  
E Coli ◽  
Disinfection Methods ◽  
Physico Chemical ◽  
Treatment Train ◽  
Pre Treatment

A study was carried out to evaluate the efficiency of secondary effluent additional treatment, using a combination of pre-treatments (ring filter, physico-chemical and infiltration-percolation) followed by disinfection methods (chlorine dioxide, peracetic acid and ultraviolet light). Three different indicator microorganisms were determined: E. coli, total coliforms and somatic bacteriophages. The results show better efficiency of physico-chemical and infiltration-percolation processes. Bacteriophages were eliminated to a lesser extent than bacterial indicators in all the treatment systems. Chlorine dioxide and peracetic acid seems to be more efficient in disinfection than ultraviolet light when a ring filter is the pre-treatment used. For the same doses and contact times, the efficiency of the disinfection methods is higher when the pre-treatment used is the physico-chemical or the infiltration-percolation system. The final effluent quality from the physico-chemical treatment train and the infiltration-percolation treatment train, followed by the disinfectants, achieves an E. coli content that allows the reuse in most of the uses described in the Spanish legislation for wastewater reuse.

A pilot-scale study of peracetic acid and ultraviolet light for wastewater disinfection

2019 ◽  
Vol 5 (8) ◽  
pp. 1453-1463 ◽  
Author(s):  
Abdulrahman H. Hassaballah ◽  
Jeremy Nyitrai ◽  
Christine H. Hart ◽  
Ning Dai ◽  
Lauren M. Sassoubre
Keyword(s):  
Ultraviolet Light ◽  
Peracetic Acid ◽  
Pilot Scale ◽  
Fecal Coliforms ◽  
Treated Wastewater ◽  
E Coli ◽  
Wastewater Disinfection ◽  
Somatic Coliphage

At the pilot-scale, peracetic acid effectively inactivates fecal coliforms,E. coliandEnterococcusspp. in secondary and tertiary treated wastewater. The addition of UV to PAA treatment increases inactivation of somatic coliphage.

Ozonation of a secondary effluent both for fresh water protection and re-use

2006 ◽  
Vol 1 (2) ◽  
Author(s):  
M. Antonelli ◽  
V. Mezzanotte ◽  
C. Nurizzo
Keyword(s):  
Contact Time ◽  
Pilot Scale ◽  
Secondary Effluent ◽  
Water Protection ◽  
Faecal Coliforms ◽  
Colour Removal ◽  
E Coli ◽  
Log Reduction ◽  
Ionic Compounds ◽  
Higher Doses

49 trials were carried out at pilot scale to evaluate ozonation for polishing a nitrified and filtered effluent discharged in a brook, lying in a recreational protected area whose low and irregular flow provides a negligible dilution. Four ozone doses (3, 5, 7.5 and 10 mg O3/L) were tested and contact time was set at 10 minutes for each of the three contact columns. In most cases, at 3 mg O3/L, residual ozone concentration was below detection limit after 10 minutes contact time. For faecal coliforms and E. coli, log reduction increased from 3 mg O3/L to higher ozone doses, among which no appreciable difference was observed. No improvement in disinfection efficiency was seen for contact times over 10 minutes. Complete disinfection was obtained only in few cases, but final counts complying with the limits for discharge were always met. COD removal was low, while colour removal was significant and clearly increasing from 3 mg O3/L to higher doses. The removal of surfactants slightly increased with increasing dose for non ionic compounds, but not for anionic ones. Data confirmed that slight increases in ozone dose involve the release of bacterial organic matter which partially counterbalance the removal of COD.

A novel electrospun polyurethane nanofibre membrane – production parameters and suitability for wastewater (WW) treatment

2014 ◽  
Vol 69 (7) ◽  
pp. 1496-1501 ◽  
Author(s):  
Jaroslav Lev ◽  
Marek Holba ◽  
Michal Došek ◽  
Libor Kalhotka ◽  
Přemysl Mikula ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Laboratory Experiments ◽  
Treatment Plant ◽  
Pilot Scale ◽  
E Coli ◽  
Bacterial Removal ◽  
Colony Forming Units ◽  
Scale Experiment ◽  
Artificial Water ◽  
Better Than

The aim of this study was to investigate the suitability of a novel electrospun polyurethane nanofibre material for water-treatment purposes. Bacterial removal efficiency was tested in the laboratory by filtering artificial water spiked with Escherichia coli through a 0.25 µm nanofibre membrane. The results were compared with those obtained using a commercial microfiltration material (MV020T) with a similar pore size (0.20 µm). Alongside the laboratory experiments, we also determined filtration efficiency with semi-pilot scale experiments using actual wastewater from the secondary sedimentation tank of a wastewater treatment plant. The laboratory experiments indicated very high log10 removal efficiency, ranging from 5.8 to 6.8 CFU (colony-forming units)/ml. These results were better than those of the commercial membrane (3.8–4.6 CFU/ml). The semi-pilot scale experiment confirmed the membrane's suitability for microbial filtration, with both E. coli and total culturable microorganisms (cultured at both 22 and 36 °C) showing a significant decline compared to the non-filtered control (wastewater from the secondary outlet).

scholarly journals Evaluation by Flow Cytometry of Escherichia coli Viability in Lettuce after Disinfection

Antibiotics ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 14
Author(s):  
Pilar Teixeira ◽  
Bruna Fernandes ◽  
Ana Margarida Silva ◽  
Nicolina Dias ◽  
Joana Azeredo
Keyword(s):  
Escherichia Coli ◽  
Flow Cytometry ◽  
Sodium Hypochlorite ◽  
Peracetic Acid ◽  
Food Microbiology ◽  
Lower Percentage ◽  
E Coli ◽  
Promising Tool ◽  
Microbiological Techniques ◽  
Foodborne Outbreaks

Foodborne outbreaks due to the consumption of ready-to-eat vegetables have increased worldwide, with Escherichia coli (E. coli) being one of the main sources responsible. Viable but nonculturable bacteria (VBNC) retain virulence even after some disinfection procedures and constitute a huge problem to public health due to their non-detectability through conventional microbiological techniques. Flow cytometry (FCM) is a promising tool in food microbiology as it enables the distinction of the different physiological states of bacteria after disinfection procedures within a short time. In this study, samples of lettuce inoculated with E. coli were subject to disinfection with sodium hypochlorite at free chlorine concentrations of 5, 10, 25, 50, and 100 mg·L−1 or with 35% peracetic acid at concentrations of 5, 10, 25, and 50 mg·L−1. The efficiency of these disinfectants on the viability of E. coli in lettuce was evaluated by flow cytometry with LIVE/DEAD stains. Results from this study suggest that FCM can effectively monitor cell viability. However, peracetic acid is more effective than sodium hypochlorite as, at half the concentration, it is enough to kill 100% of bacteria and always induces a lower percentage of VBNC. Finally, we can conclude that the recommended levels of chemical disinfectants for fresh fruit and vegetables are adequate when applied in lettuce. More importantly, it is possible to ensure that all cells of E. coli are dead and that there are no VBNC cells even with lower concentrations of those chemicals. These results can serve as guidance for lettuce disinfection, improving quality and the safety of consumption.

Approaching stability challenges for flow cytometry in a regulated bioanalytical environment

Bioanalysis ◽  
2019 ◽  
Vol 11 (20) ◽  
pp. 1845-1858 ◽  
Author(s):  
Anamica Muruganandham ◽  
Carolyne Dumont ◽  
Kuiyi Xing
Keyword(s):  
Flow Cytometry ◽  
Critical Parameter ◽  
Storage Period ◽  
Reliable Data ◽  
Clinical Samples ◽  
Sample Collection ◽  
Testing Laboratory ◽  
Stability Parameters ◽  
Stability Issues ◽  
Limited Period

Stability of samples for flow cytometry is a critical parameter since storage period of samples is restricted to only a limited period after collection. For most studies, clinical samples have to be shipped to a testing laboratory, in contrast to preclinical samples, which can be analyzed on-site or off-site. Therefore, evaluating stability is critical to provide flexibility on testing of samples to obtain reliable data. A wide variety of factors contributes to establishing stability from sample collection through acquisition. We provided suggestions for experimental and stability parameters to be taken into consideration when designing a flow cytometry method. The case studies presented represent how certain stability issues were overcome to perform flow cytometry assays in a regulated bioanalytical environment.

Tracking an Escherichia coli O157:H7–Contaminated Batch of Leafy Greens through a Pilot-Scale Fresh-Cut Processing Line

2014 ◽  
Vol 77 (9) ◽  
pp. 1487-1494 ◽  
Author(s):  
ANNEMARIE L. BUCHHOLZ ◽  
GORDON R. DAVIDSON ◽  
BRADLEY P. MARKS ◽  
EWEN C. D. TODD ◽  
ELLIOT T. RYSER
Keyword(s):  
Escherichia Coli ◽  
Membrane Filtration ◽  
Fluorescent Protein ◽  
Pilot Scale ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Leafy Greens ◽  
Iceberg Lettuce ◽  
Processing Line ◽  
Fresh Cut

Cross-contamination of fresh-cut leafy greens with residual Escherichia coli O157:H7–contaminated product during commercial processing was likely a contributing factor in several recent multistate outbreaks. Consequently, radicchio was used as a visual marker to track the spread of the contaminated product to iceberg lettuce in a pilot-scale processing line that included a commercial shredder, step conveyor, flume tank, shaker table, and centrifugal dryer. Uninoculated iceberg lettuce (45 kg) was processed, followed by 9.1 kg of radicchio (dip inoculated to contain a four-strain, green fluorescent protein–labeled nontoxigenic E. coli O157:H7 cocktail at 106 CFU/g) and 907 kg (2,000 lb) of uninoculated iceberg lettuce. After collecting the lettuce and radicchio in about 40 bags (~22.7 kg per bag) along with water and equipment surface samples, all visible shreds of radicchio were retrieved from the bags of shredded product, the equipment, and the floor. E. coli O157:H7 populations were quantified in the lettuce, water, and equipment samples by direct plating with or without prior membrane filtration on Trypticase soy agar containing 0.6% yeast extract and 100 ppm of ampicillin. Based on triplicate experiments, the weight of radicchio in the shredded lettuce averaged 614.9 g (93.6%), 6.9 g (1.3%), 5.0 g (0.8%), and 2.8 g (0.5%) for bags 1 to 10, 11 to 20, 21 to 30, and 31 to 40, respectively, with mean E. coli O157:H7 populations of 1.7, 1.2, 1.1, and 1.1 log CFU/g in radicchio-free lettuce. After processing, more radicchio remained on the conveyor (9.8 g; P < 0.05), compared with the shredder (8.3 g), flume tank (3.5 g), and shaker table (0.1 g), with similar E. coli O157:H7 populations (P > 0.05) recovered from all equipment surfaces after processing. These findings clearly demonstrate both the potential for the continuous spread of contaminated lettuce to multiple batches of product during processing and the need for improved equipment designs that minimize the buildup of residual product during processing.

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