odours: planning and nuisance
TRANSCRIPT
Topic Areas
•Agricultural Odour Nuisance – BPM
•Agric. Planning & Modelling Impacts
•Composting & A.D. Plant Odours
•“Fugitive” Odour Emissions
•Biofilters & Carbon Filters
Key Issues – Beef Farm
Demonstrating not BPM can be a
challenge for existing units.
Planning – Buildings had been extended
Lagoon was built instead of landscaping
Slurry system not straw (as applied for)
Pollution incident (collaboration with EA)
Waste gypsum bedding – “illegal” &
unsuitable
Lagoon “gassing” almost certainly an
issue
Scope of notice?
NORTH
SOUTH
WEST EAST
5%
10%
15%
20%
25%
WIND SPEED
(Knots)
>= 22
17 - 21
11 - 17
7 - 11
4 - 7
1 - 4
Calms: 0.00%
NORTH
SOUTH
WEST EAST
4%
8%
12%
16%
20%
WIND SPEED
(Knots)
>= 22
17 - 21
11 - 17
7 - 11
4 - 7
1 - 4
Calms: 0.00%
NORTH
SOUTH
WEST EAST
5%
10%
15%
20%
25%
WIND SPEED
(Knots)
>= 22
17 - 21
11 - 17
7 - 11
4 - 7
1 - 4
Calms: 0.00%
Durham Leeming
Bradford
Example Wind Roses
in UK
98th Percentile Odour Concentrations - H4
Indicative Values
More Offensive (sludges)
Moderately Offensive (manure)
Less Offensive (cooking)
1.5 ouE/m3 3 ouE/m3 6 ouE/m3
Modify thresholds, up or down, depending on local
factors
Planning Appeal precedents 3 to 5 ouE/m3
Key Issues – Poultry (& Pigs)
Demonstrating not BPM – is a challenge
for existing units.
Planning – modelling is a routine
requirement & essential if <400m
Cleaning-out odours need careful
consideration in OMP: 1 shed at a time?
Roof mounted fans make a significant
improvement (open-topped stacks)
Broilers – cyclical (every 6-7 weeks)
Layers – more constant, clean-out <1/year
Composting & AD Odours Can be modelled for planning purposes
Composting
External windrow composting (and
external maturation) are the highest
risks.
More consideration should be given to
ventilated windrows to avoid turning
In-Vessel Composting - Waste Reception
buildings & biofilters represent the
highest risks
Measuring Odour Emissions
Composting & AD Odours Can be modelled for planning purposes
AD Plants
AD Plants – highest risks are waste
reception and digestate storage.
Agricultural AD plants probably no higher
risk that a dairy farm
Food wastes are much more odorous so that
odour control of reception buildings critical.
A NEW AD PLANT – WILL ODOUR BE AN ISSUE ?Extraction from reception buildings and waste tanks to an
open biofilter
Woodchip Biofilter
New AD Plant – Risk factors
Proximity of local / sensitive receptors
Odour potential/risk of process
“Prevailing wind”
OTHER KEY ISSUES
Fugitive emissions from building/tanks
Dispersion/downwash effects
Waste Type – Agricultural low risk, food
wastes higher
A NEW AD PLANT – WILL ODOUR BE AN ISSUE ?Extraction from reception buildings and waste tanks to an
open biofilter
“Fugitive” Odour Emissions from
Reception Buildings
Wind Driven Currents Warm Air Rising
IS THERE A HIGH RISK FROM FUGITIVE
EMISSIONS?
Odour Concentrations
AD Food Waste Reception Buildings 2,000 –20,000 ouE/m3
Suggests a Low to Medium Risk
Extraction Rate vs Fugitive Risk
Proposed extraction rate – 30,000m3/hour
Building Dimensions – 36m x 20m x 8m
Compare with SEPA guidance of 3 air changes hour?
= 5.2 air changes per hour
Suggests a Low to Medium Risk
Time 11:48:20 Smoke test - extract fan on all doors closed
Time 11:48:33
Time 11:48:40 Smoke test - extract fan on pedestrian door open
Woodchip Biofilter
Building Downwash
Biofilter (ground level open)
Biofilter (10m stack)
Fan
Bio-Filters : >45-60 seconds air residence,
Irrigation, pH control, good air distribution.
Air at <40-45C?
Cover & a stack?
90+% Abatement is a realistic
target for long term performance
Media
Odour
Golden Acres Pet Food Partners - Modular
DIY Woodchip Biofilters (vs One Large Unit)
Media can be changed in rotation while
keeping 2/3rd capacity in use
Activated Carbon Filters for Abatement
Widely Used for Cooking OdoursTypically ≤0.4 second residence time
Carbon Filters for Waste Odours
Wae Excellent for “organics”/VOCs
(incl. none odorous ones)
Residence Times >2 sec
Main effect is to Adsorb, NOT to oxidise odours
Primary or Polishing Abatement
More effective with relative humidity ≤75% (moisture resistant claims for some grades of carbon.
Air may need heating/drying (better inside buildings?)
Not suitable for hot air streams (≤40C)Condensate
Drain
Carbon Filters for Waste Odours Adsorbs c 10-25+% of own weight
Carbon alone should not trap H2S,
NH3 and CH4
Commonly doped or impregnated
with 5-10% Caustic Soda for H2S
(or acid for ammonia) - this is
oxidation
Can “blind” with particulates
Can corrode filter housings (esp.
caustic)
Carbon density c500kg/m3
Can be re-generated (or waste)
Simple/reliable
How to detect saturation??
Distribution of n-butanol
detection thresholds across the population
0%
5%
10%
15%
20%
25%
30%
35%1
0
20
40
80
16
0
32
0
64
0
12
80
25
12
50
12
10
24
0
n-butanol threshold concentration, ppb
% i
n g
rou
p
Qualifying
FACTORS AFFECTING SENSITIVITY TO ODOURS
Age - Maximum acuity after puberty, a marked decrease after 70
Sex - Females generally more accurate in identifying odours
Smoking habits - Can decrease, or sometimes increase, the sensitivity
Disease - Colds, flu, infections, Alzheimer’s disease
Psychological condition –E.g. Schizophrenia changes sensitivity and perception of smell, the emotional mood also affects performance
Anosmia
Fatigue - Extended exposure to an odour