WasteMINZ Webinar 22 February 2018

Transcription

1 WasteMINZ Webinar 22 February 2018 Dr Doug Boddy Senior Air Quality Scientist Pattle Delamore Partners Ltd Auckland Ph Mob

2 About Me Doug Boddy PhD BSc (Hons) CSci MIEnvSc MIAQM CAQP PMP Senior Air Quality Scientist Environmental Impact Assessment Atmospheric Dispersion Modelling Air Pollution & Odour Control Ambient Air Quality Monitoring Odour and Dust Assessments Environmental Management Plans

3 Introduction (1) POTENTIAL TO CAUSE SIGNIFICANT ADVERSE EFFECTS ON PEOPLE S LIVES AND WELLBING COMPLAINTS ABOUT ODOUR EMISSIONS ARE ONE OF THE MOST FREQUENT ENVIRONMENTAL POLLUTION INCIDENTS REPORTED TO REGULATORY AUTHORITIES P AT T L E D E L AM O R E P AR T N E R S L T D

4 Introduction (2) DIFFICULTY BREATHING P AT T L E D E L AM O R E P AR T N E R S L T D

5 Introduction (3) Factors 1. Odour emission rate 2. Odour source 3. Location odour perceived 4. Frequency of exposure 5. Duration of exposure 6. Site conditions 7. Meteorology 8. Operating procedures 9. Odour character 10. Hedonic tone

6 Introduction (3) odour odour odour odour odour

7 Odour complaints Introduction (4) Responding to odour complaints is fraught with difficulties Can be time consuming and lead to uncertainty and conflict Assessment techniques Subjective field odour investigations Other assessment techniques are available

8 Focus of Webinar Odour sources at landfills and their potential effects Assessment techniques Assessing odour effects a case study Mitigating odour effects

9 Odour Sources and Effects PDP Feb-18 PATTLE DELAMORE PARTNERS LTD

10 Odour Sources and Effects (1) What the nose knows The sensory perception of odour Odour detection variability Spatial and temporal variability in odour Objectionable and offensive odour effects

11 Odour Sources and Effects (2) Landfill odours typically include: Rubbish odours fresh tipping or waste awaiting tipping Odours from specific waste malodorous waste Landfill gas odours - methanogenesis Landfill odours may also arise from: Leachate control and treatment - anaerobic leachate Power generation incomplete combustion (e.g. VOC)

12 Assessment Techniques PDP Feb-18 PATTLE DELAMORE PARTNERS LTD

13 Assessment Techniques (1) Complaints data analysis Review complaint data and local meteorological data Questionnaires, interviews and community meetings Field odour investigation To identify the principal sources of odour To record the odour intensity, character, frequency and duration downwind of the principal odour emission sources To identify other sources of odour in vicinity of landfill Instantaneous surface monitoring for methane As a surrogate for odour To identify emission hotspot locations (areas of peak landfill gas concentration)

14 Assessment Techniques (2) Odour emissions monitoring Area source sampling using a flux chamber Analysis by dynamic dilution olfactometry (DDO) Atmospheric dispersion modelling To assess different emission scenarios To evaluate a number of mitigation options (odour control measures) for the site Ambient air quality monitoring (e.g. H 2 S and VOC) Odour surveys Surveys, questionnaires and interviews Odour diaries Community meetings

15 Assessing Odour Effects A Case Study PDP Feb-18 PATTLE DELAMORE PARTNERS LTD

16 Assessing Odour Effects (1) Complaints data analysis History of odour complaints Complaints record 13 Feb to 3 Sep (202 days in duration) 69 complaints Same household

17 83% of complaints occurred between 4 pm and 8 am

18 Assessing Odour Effects (2) Subjective field odour assessment A subjective field odour investigation (or sniff test) was undertaken at various locations across the landfill The principal odour emission sources at the landfill were identified at the following locations: Leachate collection sump Stage 2 intermediate cover Three emission hotspots Consistent with the results of the surface monitoring for methane

19 Leachate collection P A T T Lsump E D E L A M O R E P A R T N E R S L T D Stage 2 (intermediate cover)

20 Assessing Odour Effects (3) Subjective field odour assessment Minor odour emission sources at the landfill included: Working face and active cells Placement of fresh waste Fugitive emissions of odour permeating through daily cover Leachate pond (open storage)

21 Assessing Odour Effects (4) Odour emissions monitoring Odour concentrations and emission rates were determined by DDO at the following locations: Leachate pond Leachate collection manhole Stage 2 intermediate cover (3 hotspot locations) Working face

22 Assessing Odour Effects (5) Odour emissions monitoring The results indicate that the highest odour concentrations were found at the leachate collection manhole. The odour emissions at the working face and leachate pond were relatively low compared with the leachate collection manhole.

23 LFG monitoring Assessing Odour Effects (6) A portable methane monitor was used and operated in survey mode (response time of ~0.6 seconds). The instrument automatically switched to monitor mode (response time of ~1 sec) at the leachate collection manhole and the Stage 2 emission hotspots due to high CH 4 concentrations. A GPS unit was used to determine accurate geo-spatial data at a time-resolution of ~1 sec.

24 LFG monitoring on Stage 2 LFG monitoring at leachate collection sump

25 LFG monitoring Assessing Odour Effects (7) The principal sources of CH 4 were: Leachate collection manhole (maximum concentration of 380,500 ppm) 3 emission hotspots located on Stage 2 (maxima ranged from 5,827 ppm to 39,007 ppm)

26 Assessing Odour Effects (8) Atmospheric dispersion modelling Atmospheric dispersion modelling using CALPUFF. The aim was not to confirm or deny the odour complaints history but to assess the potential benefits associated with undertaking mitigation. Furthermore, there is an accepted degree of uncertainty regarding results generated by dispersion modelling, particularly for odour.

27 Assessing Odour Effects (9) Atmospheric dispersion modelling scenarios Scenario 1 Scenario 2 Scenario 3 Baseline (existing) emissions Baseline emissions except with a biofilter to control odour at the leachate collection sump Baseline emissions except with the implementation of effective capping (e.g. clay layer) across Stage 2 to reduce fugitive odour and LFG emissions Scenario 4 Combination of Scenarios 2 and 3 (i.e. biofilter + effective capping)

28 Predicted 1-hour mean (99.9%ile) groundlevel odour concentrations (OU/m 3 ) Receptor Scenario 1 Scenario 2 Scenario 3 Scenario 4 R R R R R R R R R R R R R R R R Sensitive receptors The odour assessment criterion was 2 OU/m 3

29 1-hour mean (99.9%ile) ground-level odour concentrations (OU/m 3 ) for Scenario 1 The odour assessment criterion was 2 OU/m 3

30 Assessing Odour Effects (10) Atmospheric dispersion modelling A modelling uncertainty factor of 10 was applied: Based on a review of the potential sources of modelling error Model headroom analysis The highest odour concentrations predicted: At any location beyond the site boundary for Scenario 1 was 5 OU/m 3 (as 99.9%ile 1-hour mean) At any sensitive receptor location (receptor R1 ) was 2 OU/m 3 (as 99.9%ile 1-hour mean)

31 Assessing Odour Effects (11) Atmospheric dispersion modelling The results for Scenario 3 suggest that with the application of effective cover across Stage 2 the maximum 1-hour mean concentration (as 99.9%ile) at receptor R1 would be 1 OU/m 3. Odour has the potential to be detected from time-to-time but is unlikely to be objectionable or offensive (i.e. result in an adverse effect or nuisance complaint).

32 Assessing Odour Effects (12) Atmospheric dispersion modelling The results for Scenario 2 indicate that the biofilter alone is unlikely to result in a significant reduction in odour beyond the site boundary.

33 Assessing Odour Effects (13) Ambient monitoring for hydrogen sulphide Concentrations of H 2 S were measured at sensitive receptor R1 over a period of 3 months between 17 March and 18 June. The sampling port was positioned at a height of 2 m above ground level. An ultrasonic anemometer was co-located with the sampling port to measure wind speed and direction.

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35 New Zealand Ambient Air Quality Guideline (AAQG) for H 2 S 7 µg/m 3 as a 1-hour mean (or 5 ppb at 20 C) based on odour nuisance rather than health Averaging Period H 2 S Concentration (ppb) 1-minute minimum 1-minute maximum Odour Detection Threshold for H 2 S ~0.5 ppb (or 0.7 µg/m 3 ) 1-hour minimum 1-hour maximum 24-hour minimum 24-hour maximum month mean 0.4

36 Assessing Odour Effects (14) Ambient monitoring for hydrogen sulphide Exceedances of the AAQG were measured on 23 separate occasions, mostly during: Westerly (W) winds (43%) West-north-westerly (WNW) winds (22%) West-south-westerly (WSW) winds (13%)

37 Assessing Odour Effects (15) Ambient monitoring for hydrogen sulphide The monitoring data also indicate that the exceedances occurred during: The evening or early morning Under calm to low wind speed conditions of between 0.2 m/s and 0.7 m/s

38 Time-series plot showing1-hour mean H 2 S (ppb) for 17 March to 18 June The AAQG for H 2 S is 7 µg/m 3 as a 1-hour mean (or 5 ppb at 20 C)

39 Wind rose showing 1-hour mean wind speed and direction (17 Mar to 18 Jun)

40 Pollution rose for 1-hour mean H 2 S (ppb) and wind direction (17 Mar - 18 Jun)

41 Polar plot for 1-hour mean H 2 S (ppb), wind speed and wind direction

42 Mitigating Odour Effects PDP Feb-18 PATTLE DELAMORE PARTNERS LTD

43 Mitigating Odour Effects (1) Implement an odour management plan (OMP) Apply effective capping over intermediate cover to reduce fugitive odour/lfg emissions Expand the existing gas collection system (GCS) Treat the LFG by combustion in a new flare Treat odorous air from the leachate collection sump in a biofilter or flare

44 Mitigating Odour Effects (2) Control odour at the leachate pond (e.g. reduce residence time, avoid certain wind conditions for planned maintenance, use mechanical aeration) Control odour at the working face (e.g. keep an adequate supply of daily cover, regularly inspect cover integrity, deep and prompt burial of malodourous waste) Undertake regular monitoring, such as field odour investigations, LFG monitoring and biofilter/flare performance testing Update and enhance the odour complaints investigation and recording procedure

45 Conclusions PDP Feb-18 PATTLE DELAMORE PARTNERS LTD

46 Conclusions The principal sources of odour emissions were: Leachate collection manhole Stage 2 emission hotspots (intermediate cover) Relatively minor odour emissions from: The working face Leachate pond Employing the recommended mitigation measures will reduce the potential for further odour nuisance effects arising in the community.

47 Further Reading 1. GPG for Odour 2. GPG for Industry 3. GPG for Modelling 4. WasteMINZ Technical Guidelines Ministry for the Ministry for the Environment, 2016, Environment, WasteMINZ, 2016, 2004, Good Practice Guide Good Technical Practice Guidelines for Assessing for for Disposal Assessing Atmospheric to Land. Discharges to Air from Dispersion Managing Modelling. Odour. Industry. PDP Feb-18 PATTLE DELAMORE PARTNERS LTD

48 Questions? PDP Feb-18 PATTLE DELAMORE PARTNERS LTD

49 WasteMINZ Webinar 22 February 2018 Dr Doug Boddy Senior Air Quality Scientist Pattle Delamore Partners Ltd Auckland Ph Mob

50 Sensory Perception of Odour The sensory perception of odour depends on: Detectability Intensity Very weak Weak Distinct Strong Very strong Extremely strong Character Hedonic tone Extremely unpleasant Neutral Extremely pleasant back PDP Feb-18 PATTLE DELAMORE PARTNERS LTD

51 Good Practice Guide for Assessing and Managing Odour (November 2016) Recommended consent condition: There shall be no noxious, offensive or objectionable odour to the extent that it causes an adverse effect at or beyond the boundary of the site. PDP Feb-18 Objectionable Open to objection, unpleasant, offensive Offensive Giving or meant to give offence, disgusting, foulsmelling, nauseous, repulsive Noxious Harmful, poisonous or unpleasant. (The Oxford English Dictionary) PATTLE DELAMORE PARTNERS LTD

52 The FIDOL Factors The factors that contribute to an odour effect include: back PDP Feb-18 PATTLE DELAMORE PARTNERS LTD

53 Odour Emissions back