Bioaerosols in Waste Management Facilities Dr Ikpe Ibanga - - PowerPoint PPT Presentation

Bioaerosols in Waste Management Facilities

Dr Ikpe Ibanga I.E.Ibanga@greenwich.ac.uk 05 August 2020

Outline

• Background
• The Sniffer Project
• Research Aim & Objectives
• Methods – Biofilter construction, bioaerosol sampling
• Results
• Conclusions
• References
• Acknowledgements

• Aerosols, aeroallergens, or particulate matter of microbiological, plant or animal origin

(Defra, 2009).

• Can interact with living systems through infective, allergenic and/or toxic mechanisms.
• Aerosolised as clumps, aggregates and attached to larger mineral particles.
• Weather conditions and process parameters can affect generation and aerosolisation.
• Viability can deteriorate according to temperature, humidity and sunlight.
• Die off is generally exponential, although non-viable microorganisms may still be able to

cause health effects e.g. allergenic/toxic effects in sufficient concentrations

What are bioaerosols?

• Increase in composting activities
• They have received increased media attention over the past few years
• The risk of exposure to bioaerosols is a growing research area
• Increasing number of complaints regarding health effects and odour problems from

residents living close to composting facilities

• July 2009 – waste workers warned of the potential health impacts of bioaerosols – Dr

Alison Searl – Institute of Occupational Health “Time bomb of major respiratory health problems in the future”

• July 2009 – Waste and Resources Action Programme (WRAP) said the issue required more

investigation – relating to a study done on the impact of fortnightly bin collection.

Why are we interested in bioaerosols?

Bioaerosols from waste facilities

Bioaerosols Bacteria Fungi Viruses Spores Endotoxins Peptidoglycans Mycotoxins

Bioaerosols from waste facilities

Bioaerosols Bacteria Fungi Viruses Spores Endotoxins Peptidoglycans Mycotoxins

Viable and non- viable

Bioaerosols from waste facilities

Bioaerosols Bacteria Fungi Viruses Spores Endotoxins Peptidoglycans Mycotoxins

Pathogenic or non- pathogenic

Bioaerosols from waste facilities

Bioaerosols Bacteria Fungi Viruses Spores Endotoxins Peptidoglycans Mycotoxins

Cell wall components with toxicological properties

Bioaerosols from waste facilities

Bioaerosols Bacteria Fungi Viruses Spores Endotoxins Peptidoglycans Mycotoxins

Secondary metabolites

Bioaerosols from waste facilities

Bioaerosols Bacteria Fungi Viruses Spores Endotoxins Peptidoglycans Mycotoxins

May also find algal fragments, protozoa and nematodes but these are not routinely encountered in emissions at waste management sites

What are the potential health effects?

Direct health effects – little research carried out to establish:

• Safe levels
• Dose-response relationships

Why?

• Many different species of viable bioaerosols
• Many components (glycans, endotoxins, mycotoxins)
• Whole range of potential health effects that may have other unconnected

causes

• Human response - varied and complex

Allergic type reactions

Mucous membrane irritation Respiratory complaints Chronic bronchitis Asthma Skin irritation

Systemic Toxic Effects

Organic Dust Toxic Syndrome Fever Chills Headaches Excessive tiredness Flu-like symptoms

Invasive aspergillosis

Aspergillus us f fum umigatus us

 A rapid growing mould which survives over a wide range of conditions.  Propagated via airborne spores 2-3mm in diameter.  Opportunist pathogen – spores can enter the lungs very easily – spores may be inhaled frequently but infection is uncommon.  Wide spectrum of human illness ranging from mild respiratory tract irritation, colonisation of the bronchial tree through to rapidly invasive and disseminated disease.  Of particular concern regarding IC individuals such as bone marrow transplant, heart and lung transplants and cystic fibrosis patents.  Healthy individuals - spores are dealt with by the innate defences of the URT or if they penetrate the LRT by macrophages which ingest and kill the spores before they can go on to cause infection.

Aspergillus us f fum umigatus us

 One of the prime concerns in composting and waste management generally.  Survives over a wide range of temperature, moisture content, pH,

• xygen concentrations and on a range of substrates.

 Optimum conditions are temperatures between 37 – 43oC and substrates with high carbon content.  Spores are very small and can be carried long distances – from a few 100m up to several km.

How and why are bioaerosols generated?

Raw wastes contain high concentrations of microorganisms Microorganism growth is associated with the breakdown of organic matter Some are potentially pathogenic and can be released as bioaerosols:

• Handling of waste materials on site –

shredding, turning, screening

• Storage and movement of waste
• Material characteristics – source material,

moisture content

• Meteorological conditions – rain, wind,

humidity

Current Guidelines

• Workers in the vicinity of an activity involving material agitation – should be at least 30m

away

• 250m trigger limit – Environment Agency – Wheeler et al (2001) based on dispersal

monitoring in 1999-2000 – found background concentrations were reached within 200m

• Site specific bioaerosol risk assessment (SSBRA) must be carried out if there are sensitive

receptors within that distance from the site

• Environment Agency Acceptable Limits at 250m or Sensitive receptors:
• 500 cfu m-3 for A. fumigatus
• 1000 cfu m-3 for Total bacteria
• 300 cfu m-3 for Gram negative bacteria

Odour & Bioaerosols concerns

Measures for Odour Control

• Incineration
• Adsorption
• Misting and deodorisers
• Biofilters

What are biofilters?

Mechanism for odour control

This research project was commissioned by Sniffer on behalf of the UK environmental agencies and was carried out by a team from the University of Leeds and Odournet UK.

Key Findings

Odour up to 94% Removal (200 – 5000 OUE m-3) Bioaerosols

• performance variable with time and site; and

removal mechanism not same for odour To determine the criticality of design and

• perating parameters on biofilter performance

Study Aim & Objectives

• Evaluation of the removal efficiencies.
• Evaluation of the net bioaerosol-emitting potential
• f biofilters.
• Assessment of the impact on bioaerosol particle

size distribution between inlet and outlet samples. Biofilter Performance Assessment for Bioaerosols control

Methods

Methods

Methods

Operating Parameter Value Media type Wood chips Media porosity 61% Media density 225 Kg/m3 Media conductivity 248 µS/cm Media moisture content 40 – 70% Media height 0.5 m Surface loading 149 m3/m2/hr Volumetric loading 298 m3/m3/hr Inlet air temperature 15 – 30°C Outlet air temperature 15 – 30°C Inlet air relative humidity 70 - 95% Media pH 5.5 - 8 Gas residence time 9 – 109 s Air distribution Through a plenum, up-flow configuration

Methods

MRF – 2nd in odour complaints with ~ 5000 reports between 10/13 – 10/15 (Environment Agency, 2016)

Methods

Methods

Methods

Methods

Methods - surrogate indicator species

Aspergillus fumigatus 500 cfu m-3 Total mesophilic bacteria 1000 cfu m-3 Gram negative bacteria 300 cfu m-3

Methods - Concentration of bioaerosols in the process air reported in literature & current study

System Waste Bioaerosols Concentration (cfu m-3) Authors Various Various

• A. fumigatus

Mesophilic bacteria 102 – 105 103 – 105 Sanchez-Monedero et al. (2003)

• Mesophilic bacteria

105 - 106 Fischer et al. (2008)

• A. fumigatus

102 – 105 Kummer and Thiel (2008) Various GW/FW Bacteria Gram negative bacteria Fungi 103 – 105 104 – 105 0 – 104 Frederickson et al. (2013) Various Various

• A. fumigatus

Total bacteria Gram negative bacteria 9 – 103 103 – 104 102 – 103 Fletcher et al. (2014) MRF MSW

• A. fumigatus

Total fungi Total mesophilic bacteria Gram negative bacteria 103 – 104 103 – 104 103 – 105 103 – 105 This study

FW – Food waste, GW – Green waste, MSW – Municipal Solid Waste

Results – Operated inside the waste hall

86 78 60 77 88 72 97 49 59 35 85 78 65 76 85 72 96 61 53 35 1 2 3 4 5 6 13 14 15 16 1E+01 1E+02 1E+03 1E+04 1E+05 1E+06

(b)

Aspergillus fumigatus concentration (cfu m-3)

Visits

Background concentration Inlet concentration Outlet concentration

• 400
• 350
• 300
• 250
• 200
• 150
• 100
• 50

50 100

Removal Efficiency (%)

1 2 3 4 5 6 13 14 15 16 1E+01 1E+02 1E+03 1E+04 1E+05 1E+06

Total fungi concentration (cfu m-3)

Visits

• 400
• 350
• 300
• 250
• 200
• 150
• 100
• 50

50 100

Removal Efficiency (%)

70% (35 – 97%) 71% (35 – 94%)

67 85 52 80 86 75 83 50 53 47 80

• 4

85 46 68 21 65 71 18 52

(b)

1 2 3 4 5 6 13 14 15 16 1E+01 1E+02 1E+03 1E+04 1E+05 1E+06

Total mesophilic bacteria concentration (cfu m-3)

Visits

• 400
• 350
• 300
• 250
• 200
• 150
• 100
• 50

50 100

Removal Efficiency (%)

1 2 3 4 5 6 13 14 15 16 1E+01 1E+02 1E+03 1E+04 1E+05 1E+06

Gram negative bacteria concentration (cfu m-3)

Visits

• 400
• 350
• 300
• 250
• 200
• 150
• 100
• 50

50 100

(a)

Removal Efficiency (%)

Background concentration Inlet concentration Outlet concentration

Results – Operated inside the waste hall

68% (47 – 86%) 50% (-4 – 85%)

82 93 94

• 0.4

58

• 83

72 94 94 21 50 45 7 8 9 10 11 12 1E+01 1E+02 1E+03 1E+04 1E+05 1E+06

Aspergillus fumigatus concentration (cfu m-3) Visits

Background concentration Inlet concentration Outlet concentration

• 400
• 350
• 300
• 250
• 200
• 150
• 100
• 50

50 100

Removal Efficiency (%)

7 8 9 10 11 12 1E+01 1E+02 1E+03 1E+04 1E+05 1E+06

Total fungi concentration (cfu m-3) Visits

• 400
• 350
• 300
• 250
• 200
• 150
• 100
• 50

50 100

Removal Efficiency (%)

(b) ( )

Results – Operated outside the waste hall

64 83 40

• 122
• 2

38 54 24

• 128

23

• 125

33 7 8 9 10 11 12 1E+01 1E+02 1E+03 1E+04 1E+05 1E+06

(b)

Total mesophilic bacteria concentration (cfu m-3) Visits

(a)

• 400
• 350
• 300
• 250
• 200
• 150
• 100
• 50

50 100

Removal Efficiency (%)

7 8 9 10 11 12 1E+01 1E+02 1E+03 1E+04 1E+05 1E+06

Gram negative bacteria concentration (cfu m-3) Visits

• 400
• 350
• 300
• 250
• 200
• 150
• 100
• 50

50 100

Removal Efficiency (%)

Background concentration Inlet concentration Outlet concentration

Results – Operated outside the waste hall

Results

2 3 4 5

• 300
• 200
• 100

100

2 3 4 5 2 3 4 5 2 3 4 5

Aspergillus fumigatus

Bioaerosol removal efficiency (%) log10(Bioaerosol inlet concentration) (cfu m

• 3)

y = 27.09*x - 36.35 Total fungi y = 5.24*x + 48.43 Total mesophilic bacteria y = 51.21*x - 156.31

Bioaerosol removal efficiency (%)

Gram negative bacteria y = 69.98*x - 238.42

• 300
• 200
• 100

100

Fungi Bacteria

R2 = 0.16 R2 = 0.37 R2 = 0.36 R2 = 0.02

Results

BF4 outlet BF3 outlet BF2 outlet BF1 outlet Inlet Background 20 40 60 80 100

Aspergillus fumigatus (a)

>7 µm 4.7 - 7 µm 3.3 - 4.7 µm 2.1 - 3.3 µm 1.1 - 2.1 µm 0.65 - 1.1 µm

20 40 60 80 100

Total fungi (b)

20 40 60 80 100

Total mesophilic bacteria (c)

20 40 60 80 100

Gram negative bacteria (d)

% of particles in each size range

Results – Aspergillus us f fum umigatus us

~70%: < 3.3µm ~ 35%: < 3.3µm

Results – Total Mesophilic Bacteria

~65%: < 3.3µm ~ 45%: < 3.3µm

Conclusions

• Removal Efficiencies – up to 97% (A. fumigatus), 94% (total

fungi), 86% (total mesophilic bacteria), and 85% (Gram negative bacteria).

• Differences may exist between fungi and bacteria removal,

as there is much more confidence with the performance for bacteria than fungi - may be size-related.

• Inlet concentrations is important especially for bacteria.
• Biofilters maybe net-emitters of bioaerosols at low inlet

concentration.

• Particle size distribution vary between the inlet and outlet

air – high proportion of <3µm in outlet samples.

References

• Chen, L. and Hoff, S.J. 2012. A Two-Stage Wood Chip-Based Biofilter System to Mitigate Odors

from a Deep-Pit Swine Building. Applied Engineering in Agriculture. 28(6), pp.893 - 901.

• Fischer, G., Albrecht, A., Jäckel, U. and Kämpfer, P. 2008. Analysis of airborne microorganisms,

MVOC and odour in the surrounding of composting facilities and implications for future

• investigations. International Journal of Hygiene and Environmental Health. 211(1), pp.132-142.
• Fletcher, L.A., Jones, N., Warren, L. and Stentiford, E.I. 2014. Understanding biofilter performance

and determining emission concentrations under operational conditions. Edinburgh, Scotland,: Sniffer.

• Frederickson, J., Boardman, C.P., Gladding, T.L., Simpson, A.E., Howell, G. and Sgouridis, F. 2013.

Evidence: Biofilter performance and operation as related to commercial composting. Environment Agency, Bristol.

• Kummer, V. and Thiel, W.R. 2008. Bioaerosols–sources and control measures. International

Journal of Hygiene and Environmental Health. 211(3-4), pp.299-307.

• Sanchez-Monedero, M.A., Stentiford, E.I. and Mondini, C. 2003. Biofiltration at Composting

Facilities: Effectiveness for Bioaerosol Control. Environmental Science & Technology. 37(18), pp.4299-4303.

PhD Supervisors:

Dr Louise Fletcher Prof Catherine Noakes