Microbial safety of air-dried and rewetted biosolids

To assess microbial safety of treated sewage sludge (biosolids), we examined the inactivation of microbial indicators for potential bacterial, viral and protozoan pathogens. The levels of indicators were determined throughout the air-drying and storage phases of anaerobically digested sewage sludge. Samples were collected from two wastewater treatment plants (WWTPs) in Victoria, Australia. Established methods were applied for analysis of bacteria and coliphages, based on membrane filtration and layered plates, respectively. In the pan drying phase, the prevalence of Escherichia coli was reduced by >5 log10 compared with sludge entering the pan. Thus, after pan drying of 8-11 months at WWTP A and 15 months at WWTP B, the numbers of E. coli were reduced to below 102 cfu/g dry solids (DS). This level is acceptable for unrestricted use in agriculture in Australia (P1 treatment grade), the UK (enhanced treatment status) and the USA (Class A pathogen reduction). Coliphage numbers also decreased substantially during the air-drying phase, indicating that enteric viruses are also likely to be destroyed during this phase. Clostridium perfringens appeared to be an overly conservative indicator. Survival, but not regrowth, of E. coli or Salmonella was observed in rewetted biosolids (15–20% moisture content), after being seeded with these species, indicating a degree of safety of stored biosolids upon rewetting by rain.

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Methods for enumeratingEscherichia coliin subtropical waters

Epidemiology and Infection ◽

10.1017/s0950268800048494 ◽

1991 ◽

Vol 106 (2) ◽

pp. 345-354 ◽

Cited By ~ 2

Author(s):

W. H. S. Cheung ◽

D. K. K. Ha ◽

K. Y. Yeung ◽

R. P. S. Hung

Keyword(s):

Membrane Filtration ◽

Good Alternative ◽

Environmental Waters ◽

Filtration Method ◽

E Coli ◽

Bacterial Indicator ◽

Urease Test ◽

The Uk ◽

Mls Method

SUMMARYThe standard membrane filtration method of the UK has been modified in order to improve its specificity for enumeratingEscherichia coliin the subtropical waters of Hong Kong. This involves incorporating into the membrane lauryl sulphate (mLS) method either anin situurease test (the mLS-UA method), or anin situβ-glucuronidase test (the mLS-GUD method). The false-positive errors of the mLS-UA and mLS-GUD methods are low, ranging from 3–5%. A comparison between the membrane filtration (mLS-UA) method and the multiple tube technique in testingE. coliin subtropical beach-waters has demonstrated that the former can give much more precise counts, and is the method of choice for such a purpose. The mLS-GUD method, for which automated counting ofE. colicolonies is possible, is a good alternative to mLS-UA in routine enumeration of this bacterial indicator in environmental waters.

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Occurrence of multiclass UV filters in treated sewage sludge from wastewater treatment plants

Chemosphere ◽

10.1016/j.chemosphere.2011.04.003 ◽

2011 ◽

Vol 84 (8) ◽

pp. 1158-1165 ◽

Cited By ~ 94

Author(s):

Pablo Gago-Ferrero ◽

M. Silvia Díaz-Cruz ◽

Damià Barceló

Keyword(s):

Wastewater Treatment ◽

Sewage Sludge ◽

Wastewater Treatment Plants ◽

Uv Filters ◽

Treated Sewage

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Removal of antibiotic resistant E. coli in two Norwegian wastewater treatment plants and by nano- and ultra-filtration processes

Water Science & Technology ◽

10.2166/wst.2017.642 ◽

2017 ◽

Vol 77 (4) ◽

pp. 1115-1126 ◽

Cited By ~ 16

Author(s):

Carsten Ulrich Schwermer ◽

Pawel Krzeminski ◽

Aina Charlotte Wennberg ◽

Christian Vogelsang ◽

Wolfgang Uhl

Keyword(s):

Wastewater Treatment ◽

Membrane Filtration ◽

Municipal Wastewater ◽

Wastewater Treatment Plants ◽

Considerable Change ◽

Resistant Bacteria ◽

Antibiotic Resistant ◽

E Coli ◽

Physical Chemical ◽

Ultra Filtration

Abstract The effectivity of different treatment stages at two large wastewater treatment plants (WWTPs) located in Oslo, Norway, to remove antibiotic resistant Escherichia coli from municipal wastewater was investigated. The WWTPs were effective in reducing the total cultivable E. coli. The E. coli in WWTP samples were mainly resistant to ampicillin (6–27%) and trimethoprim-sulfamethoxazole (5–24%), and, to a lesser extent, tetracycline (3–14%) and ciprofloxacin (0–7%). In the first WWTP, a clear decrease in the percentage of E. coli resistant to these antibiotics was found, with the main removal occurring during physical/chemical treatment. In the second WWTP, the percentage of cultivable resistant E. coli did not display a considerable change. During laboratory-scale membrane filtration of WWTP effluents using ultrafiltration (UF) and nanofiltration (NF) membranes, all E. coli, including those resistant to antibiotics, were removed completely. The results imply that UF and NF processes are potent measures to remove antibiotic resistant bacteria (ARB) during post-treatment of WWTP effluents, thus reducing the potential spread of antibiotic resistance in the receiving aquatic environment.

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Hygienic Quality of Sewage Sludge Compost

Water Science & Technology ◽

10.2166/wst.1983.0016 ◽

1983 ◽

Vol 15 (1) ◽

pp. 181-194 ◽

Cited By ~ 6

Author(s):

J H Nell ◽

A G Steer ◽

P A J van Rensburg

Keyword(s):

Sewage Sludge ◽

Fungal Pathogens ◽

Health Hazard ◽

Pilot Scale ◽

Indicator Organisms ◽

Sludge Treatment ◽

Air Drying ◽

E Coli ◽

Degree Of Control

The numerous bacterial, viral, protozoal, helminthic and fungal pathogens in sewage are concentrated in raw sewage sludge during primary sedimentation. Anaerobic digestion, air-drying and activated sludge treatment may reduce the levels of these organisms, but a risk to human health still remains. Although the magnitude of this risk cannot be quantified or even predicted at this stage, the probability of infection must be minimised to protect the community. Composting reduces the health hazard by decreasing the virulence (numbers and viability) of pathogenic organisms. Results of experiments conducted by the NIWR showed that total coliforms, E. coli, coliphage, Salmonella and Ascaris ova can be eliminated in less than a week in a pilot-scale composter utilising dewatered raw and air-dried digested sludges with wood chips and refuse as filler material. In full-scale plants elimination of indicator organisms took much longer, depending on the degree of control exercised.

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Agro-ecological Characterization of Vermicomposted Sewage Sludge from Municipal and Poultry Enterprise Wastewater Treatment Plants

Sains Malaysiana ◽

10.17576/jsm-2021-5008-03 ◽

2021 ◽

Vol 50 (8) ◽

pp. 2167-2178

Author(s):

Diyana Dermendzhieva ◽

Toncho Dinev ◽

Gergana Kostadinova ◽

Georgi Petkov ◽

Georgi Beev

Keyword(s):

Wastewater Treatment ◽

Sewage Sludge ◽

Wastewater Treatment Plants ◽

Poultry Meat ◽

Plate Count ◽

Lumbricus Rubellus ◽

Microbiological Analysis ◽

Salmonella Spp ◽

E Coli

The purpose of this study was to make an agro-ecological characterization of vermicompost (VC) produced from sewage sludge (SS). As a substrate, SS from municipal and poultry meat processing enterprise wastewater treatment plants (MTP and PTP, respectively) was utilized. The substrates were vermicomposted by Red Californian earthworm (Lumbricus rubellus) for 120 days. For VC quality assessment, 19 physicochemical and 6 microbiological parameters were used. The evaluation of physicochemical parameters was done according to ISO standard methods and microbiological analysis-by plating 1 mL of sample dilutions on selective, chromogenic culture medium sheets. It was found that the vermicompost from MTP (VC-M) had higher levels of EC, mineral elements (N, P and K compounds in forms available to plants), heavy metals (Mn, Cu, Zn, Cr, Ni, Pb, Cd) and coliforms, and lower levels of pH, TOC, C/N ratio, Fe, total plate count (TPC), Enterobacteriaceae and Salmonella spp. counts compared to VC from PTP (VC-P). During the vermicomposting process, the substrates from both wastewater treatment plants (TPs) showed similar trends towards decrease in pH, TOC, N-NH4+, C/N ratio, TPC, coliforms, E. coli, Enterobacteriaceae and Salmonella spp. counts, whereas the opposite trends were established for EC, TKN, N-NO3-, TP, P2O5, TK, and K2O values. The vermicomposting had a negligible effect on heavy metal concentrations. In the final substrates E. coli were not detected, while the bacterial spore forms (Clostridium perfringens) were not eliminated. The final substrates cannot be used as fertilizers or soil amendments because of the presence of Salmonella spp. and C. perfringens over the permissible limits according to EU and Bulgarian regulations.

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Enteric viruses in municipal wastewater effluent before and after disinfection with chlorine and ultraviolet light

Journal of Water and Health ◽

10.2166/wh.2019.111 ◽

2019 ◽

Vol 17 (5) ◽

pp. 670-682 ◽

Cited By ~ 7

Author(s):

Albert Simhon ◽

Vince Pileggi ◽

Cecily A. Flemming ◽

José R. Bicudo ◽

George Lai ◽

...

Keyword(s):

Membrane Filtration ◽

Municipal Wastewater ◽

Wastewater Treatment Plants ◽

Uv Light ◽

Geometric Mean ◽

Enteric Viruses ◽

Enteric Virus ◽

Wastewater Effluent ◽

Uv Disinfection ◽

E Coli

Abstract In Ontario, Canada, information is lacking on chlorine and ultraviolet (UV) light disinfection performance against enteric viruses in wastewater. We enumerated enteroviruses and noroviruses, coliphages, and Escherichia coli per USEPA methods 1615, 1602, and membrane filtration, respectively, in pre- and post-disinfection effluent at five wastewater treatment plants (WWTPs), with full-year monthly sampling, and calculated log10 reductions (LRs) while WWTPs complied with their monthly geometric mean limit of 200 E. coli/100 mL. Modeling of densities by left-censored estimation and Bayesian inference gave very similar results. Polymerase chain reaction (PCR)-detected enteroviruses and noroviruses were abundant in post-disinfection effluent (mean concentrations of 2.1 × 10+4–7.2 × 10+5 and 2.7 × 10+4–3.6 × 10+5 gene copies (GC)/L, respectively). Chlorine or UV disinfection produced modest LRs for culture- (0.3–0.9) and PCR-detected enteroviruses (0.3–1.3), as well as noroviruses GI + GII (0.5–0.8). Coliphages and E. coli were more susceptible, with LRs of 0.8–3.0 and 2.5, respectively. Sand-filtered effluent produced significantly higher enteric virus LRs (except cultured enteroviruses). Coliphage and human enteric virus densities gave significantly positive correlations using Kendall's Tau test. Enteric viruses are abundant in wastewater effluent following routine chlorine or UV disinfection processes that target E. coli. Coliphages appear to be good indicators for evaluating wastewater disinfection of enteric viruses.

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Evaluation of Sewage Sludge for Further Nutrient Conservation

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.850.166 ◽

2020 ◽

Vol 850 ◽

pp. 166-171

Author(s):

Viktors Vibornijs ◽

Alina Rimkus ◽

Laila Dubova ◽

Dmitrijs Bekkers ◽

Natalya Strunnikova ◽

...

Keyword(s):

Pressure Drop ◽

Sewage Sludge ◽

Wastewater Treatment Plants ◽

Rational Solution ◽

Point Of View ◽

Initial Stage ◽

Methodical Approach ◽

Treated Sewage ◽

Microbial Biodegradation ◽

Nutrient Conservation

Conversion of organic-containing sludges to a high value fertilizer is considered to be a rational solution from a recycling point of view. Aerobic respiration could serve as an indicator of stability and maturity of the treated sewage sludge (SS). The aim of this study was to characterize two SS samples, obtained from different wastewater treatment plants („D” and „J”), i.e, at the initial stage of treatment, alone and with amendments. Two methods for estimation of microbial respiration, as well as dehydrogenase activity were used. The SS-J demonstrated the higher microbial biodegradation activity, as compared to SS-D. In experiments with OxiTop® device, statistically significant (p<0.05) differences of the pressure drop between SS-J and SS-D have been revealed. Addition of peat to SS resulted in a more intensive pressure drop, compared to non-amended SS, i.e., -145 hPa vs. -76 hPa for SS-D and-199 hPa vs. -180 hPa for SS-J, respectively. The obtained results represent a methodical approach for characterization of raw SS in order to evaluate the amount of aerobically degradable organic substances and intensity of their oxidation. Further research is needed for highlighting the mechanisms responsible for interrelation of respiration intensity, bacterial community activity and other metabolic changes towards SS stabilization.

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Effect of Thermal Drying and Chemical Treatments with Wastes on Microbiological Contamination Indicators in Sewage Sludge

Microorganisms ◽

10.3390/microorganisms8030376 ◽

2020 ◽

Vol 8 (3) ◽

pp. 376 ◽

Cited By ~ 1

Author(s):

Andreia F. Santos ◽

Cátia P. Santos ◽

Ana M. Matos ◽

Olga Cardoso ◽

Margarida J. Quina

Keyword(s):

Sewage Sludge ◽

Wastewater Treatment Plants ◽

Coal Fly Ash ◽

Microbiological Contamination ◽

Salmonella Spp ◽

Positive Role ◽

E Coli ◽

Chemical Treatments ◽

Green Liquor Dregs ◽

Thermal Drying

This work aims to evaluate the microbiological contamination of sewage sludge (SS) collected in urban wastewater treatment plants (WWTP) from Portugal. Two types of SS were considered: urban mixed (UM) and from anaerobic digestion (AD). The two types of samples were characterized in relation to the main physical and chemical parameters, as well as the microbiological contamination (Escherichia coli and Salmonella spp). Then, sanitation tests were conducted through thermal drying and chemical treatments. Towards a circular economy, industrial alkaline wastes (green liquor dregs - GLD, lime mud, coal fly ash, eggshell) were tested as alternatives to lime. Only six out of nineteen samples complied with the legal limits for both microorganisms. However, drying at 130 °C sanitized selected samples below the E. coli limit, regardless of the initial moisture or contamination. Additionally, CaO (obtained from eggshell) led to the complete elimination of E. coli at any dosage studied (0.05–0.15 g/g SSwet basis). GLD evidenced the ability to reduce E. coli contamination at room temperature, but not enough to comply with the legal limit. In general, this work highlights the need to sanitize the SS before its application to the soil, and the positive role of some wastes on this goal.

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The Influence of Glycosylation on the Catalytic and Fibrinolytic Properties of Pro-Urokinase

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646314 ◽

1992 ◽

Vol 68 (05) ◽

pp. 539-544 ◽

Cited By ~ 22

Author(s):

Catherine Lenich ◽

Ralph Pannell ◽

Jack Henkin ◽

Victor Gurewich

Keyword(s):

Escherichia Coli ◽

Mammalian Cell ◽

Human Gene ◽

Culture Media ◽

Mammalian Cell Culture ◽

Glycosylation Site ◽

Clot Lysis ◽

Cell Culture Media ◽

E Coli ◽

The Uk

SummaryWe previously found that human pro-UK expressed in Escherichia coli is more active in fibrinolysis than recombinant human pro-UK obtained from mammalian cell culture media. To determine whether this difference is related to the lack of glycosylation of the E. coli product, we compared the activity of E. coli-derived pro-UK [(-)pro-UK] with that of a glycosylated pro-UK [(+)pro-UK] and of a mutant of pro-UK missing the glycosylation site at Asn-302 [(-) (302) pro-UK]. The latter two pro-UKs were obtained by expression of the human gene in a mammalian cell. The nonglycosylated pro-UKs were activated by plasmin more efficiently (≈2-fold) and were more active in clot lysis (1.5-fold) than the (+)pro-UK. Similarly, the nonglycosylated two-chain derivatives (UKs) were more active against plasminogen and were more rapidly inactivated by plasma inhibitors than the (+)UK.These findings indicate that glycosylation at Asn-302 influences the activity of pro-UK/UK and could be the major factor responsible for the enhanced activity of E. coli-derived pro-UK.

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An early mainstream economist from Hungary: István Varga (1897–1962)

Acta Oeconomica ◽

10.1556/aoecon.53.2003.2.4 ◽

2003 ◽

Vol 53 (2) ◽

pp. 195-213 ◽

Cited By ~ 1

Author(s):

K. Majoros

Keyword(s):

Austrian Economic ◽

National Income ◽

Anglo Saxon ◽

Turbulent Times ◽

The Usa ◽

New Ideas ◽

Modern Economic ◽

The Uk ◽

Economic Thinking ◽

Lasting Influence

The study introduces a Hungarian economic thinker, István Varga*, whose valuable activity has remained unexplored up to now. He became an economic thinker during the 1920s, in a country that had not long before become independent of Austria. The role played by Austria in the modern economic thinking of that time was a form of competition with the thought adhered to by the UK and the USA. Hungarian economists mainly interpreted and commented on German and Austrian theories, reasons for this being that, for example, the majority of Hungarian economists had studied at German and Austrian universities, while at Hungarian universities principally German and Austrian economic theories were taught. István Varga was familiar not only with contemporary German economics but with the new ideas of Anglo-Saxon economics as well — and he introduced these ideas into Hungarian economic thinking. He lived and worked in turbulent times, and historians have only been able to appreciate his activity in a limited manner. The work of this excellent economist has all but been forgotten, although he was of international stature. After a brief summary of Varga’s profile the study will demonstrate the lasting influence he has had in four areas — namely, business cycle research and national income estimations, the 1946 Hungarian stabilisation program, corporate profit, and consumption economics — and will go on to summarise his most important achievements.

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