Bioaerosol emissions from waste composting and recycling · HSL report . HSL: HSE’s Health and ... MRF project . HSL: HSE’s Health and Safety Laboratory © Crown Copyright, HSL

HSL: HSE’s Health and Safety Laboratory © Crown Copyright, HSL 2016 HSL: HSE’s Health and Safety Laboratory © Crown Copyright, HSL 2016

Brian Crook

IAPSC Meeting, December 2016

Bioaerosol emissions from waste composting and recycling

HSL: HSE’s Health and Safety Laboratory © Crown Copyright, HSL 2016

What this talk will cover

Bioaerosols and bioaerosol exposure;

Bioaerosols in the context of waste and recycling;

Example 1 - Occupational exposure to compost bioaerosols and downwind dispersion;

Example 2 – Materials Recycling Facilities;

Current and future HSE/L Waste & Recycling Programme.

Overview


Sources of bioaerosols

Bioaerosols always naturally present from various sources – dust, water, vegetation, animals;

Range in numbers and predominant species – seasonal, geographic, local sources;

Further influenced by human activities – agriculture, construction, vehicles.

Overview


Bioaerosols in the context of waste & recycling

Waste & recycling – economic, conservation and legal drivers;

Some areas of work automated, but some manual input;

Waste & recycling involving organic materials – energy input to processes will generate dust and bioaerosols.

Overview


Commercial composting

Compost handling – dust, bioaerosol generation; noise; physical risks; odour.

Composting


Materials Recycling Facilities (MRF)

Materials reception;

Some automatic

sorting……

MRF


Materials Recycling Facilities (MRF)

…..But a lot of manual sorting;

Some LEV but not always.

MRF


Waste & recycling bioaerosols and health – Aspergillus fumigatus and endotoxin

Workers’ exposure to bioaerosols;

Dispersion neighbours (other workplaces, passers by, residents).

Why are we concerned about Aspergillus fumigatus?

Prolific spore producer;

Spores are respirable;

Allergen, opportunist pathogen.

Why are we concerned about endotoxin?

Gram –ve bacterial cell wall;

Immunotoxic;

Cause inhalation fever.

Health risk


Dust and bioaerosol measurement in waste & recycling

• Air sampling – methods used by HSL • Seven MRF facilities once each; • Six composting facilities, fourteen site sampling visits at

different times of year; • Inhalable and respirable dust; bioaerosol exposure with

‘exposure banding’.

Measurement


Results of HSL research

Exposure levels – HSL’s recent work: http://www.hse.gov.uk/research/rrhtm/rr786.htm

Workers’ personal exposure;

Deriving source terms for modelling dispersion;

Measuring levels at different distances downwind to validate models and establish risk zones.

HSL report


Risk Zones (HSL Report data)

• Red zone – next to composting activity;

• Amber zone – within 50m

• Yellow zone –50 to 100m

• Green zone –100 to 250m

• Green box – background 50m+ upwind

HSL report


Red zone exposure data

If you are working next to composting handling machinery and not protected within a vehicle cab:

There is a 24% chance of being exposed to more than 100,000 cfu/m3 Aspergillus fumigatus fungus spores and a 4% chance of being exposed to more than 1 million cfu/m3 Aspergillus fumigatus spores.

HSL report


Green zone exposure data

Nearer the site boundary, that is, 100 to 250 metres from composting:

There is only a 2% chance that exposure to airborne Aspergillus fumigatus spores will be more than 5,000 cfu/m3 and 17% chance that exposure to airborne Aspergillus fumigatus spores will be more than 1,000 cfu/m3 .

HSL report


Background exposure data

Beyond the site boundary, at least 50 metres upwind from composting:

No samples of airborne Aspergillus fumigatus spores yielded more than 1,000 cfu/m3 .

HSL report


Protection afforded by vehicle cabs

Measured bioaerosols inside and outside cabs;

Bioaerosol levels reduced inside cabs – variable but with a median value of a four-fold reduction ;

Suggests need for further examination.

HSL report


HSL study in MRFs –what we did

Occupational hygiene surveys at seven MRFs. Each visit aimed to measure task- related exposures to dust and bioaerosols at all stages of the recycling process mainly by personal monitoring;

In addition, exposure control strategies assessed including management systems (COSHH assessments, operator training etc.), engineering controls and the PPE regime.

MRF project


HSL study in MRFs –what we did

Data available from HSE Research Report series (http://www.hse.gov.uk/research/rrhtm/rr977.htm)

MRF project

http://www.hse.gov.uk/research/rrhtm/rr977.htm

http://www.hse.gov.uk/research/rrhtm/rr977.htm


Workers’ potential dust exposure

139 exposures measured for inhalable dust and micro-organisms during periods representative of typical working conditions;

8-hr TWA exposures to inhalable dust ranged from 0.15 to 22.63 mg/m3;

Seven (5%) of the exposures were above the 8-hr TWA inhalable dust limit set at 10 mg/m3.

MRF project


Workers’ potential endotoxin exposure

8-hr TWA exposures to endotoxin ranged from less than the LOD to 2399 EU/m3 (8hr TWA);

47 (34%) were above the 8hr TWA health based occupational exposure limit proposed by DECOS for airborne endotoxin of 90 endotoxin units (EU)/m3;

The majority of the exposures over 90 EU/m3

were measured at MRFs that used high energy sorting machinery.

MRF project


Other potential microbial exposure

Exposure to inhalable bacteria ranged from 102 to 105 cfu/m3. None was greater than 106 but 102 (73%) exposures were greater than 104;

Exposure to inhalable fungi ranged from 102 to 105. None was greater than 106 but 113 (81%) were greater than 104;

Exposure to Aspergillus fumigatus ranged from less than the LOD to 105. 17 (12%) were greater than 104 and a further 20 (14%) greater than 103.

MRF project


Occupational hygiene data

Risk assessments had either not been carried out or were in need of review at most sites;

None of the 7 sites used LEV inside the sorting stations effectively to reduce operator exposure;

One site had LEV with capturing hoods placed in areas where potential for dust generation, but exposures measured were among the highest, indicating limited effectiveness as a measure to control exposure;

Use of respiratory protection was sporadic and the protective effect of the masks used was limited.

MRF project


What this adds to current data - composting

Compost bioaerosol exposure levels – from HSL’s study:

Workers’ potential personal exposure;

Task-specific bioaerosol exposure data;

Possible protection afforded by vehicle cabs;

‘Risk zone’ approach applicable on sites;

Deriving source terms for modelling downwind dispersion;

Measuring levels downwind to validate models.

Summary


What this tells us about MRFs

Large proportion of manual work handling waste materials;

Workers’ potential personal exposure to dust and potentially allergenic bioaerosols;

Exposure controls are basic;

WHAT ABOUT OTHER WASTE AND RECYCLING FACILITIES, AND EMERGING ENERGY TECHNOLOGIES SUCH AS BIOMASS TO ENERGY?

Summary


Current and future bioaerosol research

HSL currently completing exposure study of workers in biomass handling – municipal waste transfer stations, mechanical-biological treatment plant materials handling areas;

At one, compared day shift routine cleaning with night shift cleaning and maintenance);

Daytime : endotoxin from 127 -210 EU/m3; bacteria 4.0 x 103 – 4.4 x 104 cfu/m3; fungi 8.0 x 104 – 1.0 x 105 cfu/m3;

Night-time : endotoxin from 117 -1040!! EU/m3; bacteria 2.6 x 104 – 3.6 x 105 cfu/m3; fungi 1.1 x 105 – 4.0 x 105 cfu/m3.

Summary


Summary

Long-term high level exposure to bioaerosols causes respiratory health problems – lower level chronic exposure less obvious but still detrimental effect;

Composting bioaerosols disperse quickly with distance from source, so main effect is on workforce;

Control options are limited but need to used effectively;

Some tasks, such as cleaning and maintenance, can increase exposure.

Summary

Documents

Bioaerosol emissions from waste composting and recycling · HSL report . HSL: HSE’s Health and ... MRF project . HSL: HSE’s Health and Safety Laboratory © Crown Copyright, HSL