Presentation is loading. Please wait.

Presentation is loading. Please wait.

Engineering Assessment of Hydrogen Sulfide Issues Emission Inventory State Survey of Ambient Air Standards Regulatory Practice in Other States H 2 S from.

Similar presentations


Presentation on theme: "Engineering Assessment of Hydrogen Sulfide Issues Emission Inventory State Survey of Ambient Air Standards Regulatory Practice in Other States H 2 S from."— Presentation transcript:

1 Engineering Assessment of Hydrogen Sulfide Issues Emission Inventory State Survey of Ambient Air Standards Regulatory Practice in Other States H 2 S from Hog Farms Dispersion Modeling Study H 2 S Stability Proposed Control Technologies

2 Emission Inventory Initial records based on 1999 NC-DAQ Inventory Revised in 2002 to include paper mill wastewater treatment, 89% of paper industry emissions Soft WWT estimates; high variability data base Fertilizer and paper are most emissive industries Hog farms excluded due to poor data quality - Data overstates NC hog emissions by more than 10-fold

3 Figure 1. 1999 Emissions Inventory Total = 4.2 Million lb H 2 S/yr

4 Figure 2. Revised 2002 Inventory Total = 11.9 Million lb H 2 S/yr

5 Table 1. H 2 S Emissions Inventories Affected Industries 1999 Emission Inventory (lb) 2002 Revised Inventory (lb) Fertilizer3,500,00082%6,617,30456% Pulp + Paper672,28116%5,226,22744% Mineral Wool51,5621%51,5620% Asphalt7,0440%7,0440% Other19,2630%12,6210% (a) (a) = Potential emissions, max hour repeated all year.

6 Table 2. Pulp Mill Emission Sources Percent WWTS WWTS (lb/yr) PLANT PROPER (lb/yr) Blue Ridge51%110,989107,990 Wey-Plymouth97%3,524,823107,152 Wey-New Bern93%558,45039,858 IP-Riegelwood80%582,540141,912 IP-Roanoke Rpd47%210,280236,914 TOTAL4,987,082633,826 Weighted Avg.89%

7 State Survey of Ambient Air Standards No federal ambient air standards 35 states set their own standards - 13 with 1-hr from 14-280 ug/m 3 (10 – 200 ppb) - 13 with 24-hr from 8.4-280 ug/m 3 (0.6 – 200 ppb) - 26 other standards - Several states have more than 1 standard

8 Figure 3. All states with H 2 S Standards

9 Figure 4. States with 1-hr H 2 S Standards

10 Figure 5. States with 24-hr H 2 S Standards

11 H 2 S Regulatory Practice in Other States Contacted 4 similar states - South Carolina - Georgia - Minnesota - Wisconsin

12 South Carolina H 2 S Program Effective in 1991; 100 ppb 24-hr standard Compliance by modeling or monitoring Existing facilities 2 yrs to demonstrate Modeled parameters included in permit MACT compliant facilities are exempt 3 of 7 paper mills modeled for H2S - Only 1 included WWTS: 1.6 Million lb/yr

13 Georgia H 2 S Program Guidelines for assessment Facility derives acceptable ambient level Use EPA, OSHA, ACGIH or NIOSH limits Model with 5 yrs met data to determine maximum ground level concentration If max concentration more than AAL, then reduce max concentration responsibly All subject to agency review & approval

14 Minnesota H 2 S Program Effective in 1969; - 30 ppb 30-min standard - 50 ppb 30-min std w/2 exceedances/yr In ~1988 paper mills exceeded H 2 S standard - Installed activated sludge units initially - Then added covers and oxygenation Mills meet 30 and 50 ppb standards

15 Minnesota H 2 S Program (cond) Recently found hog farm H 2 S problem Trend of fewer, but larger farms State colleges do much research State agency responds to odor complaints - Uses ambient monitors to measure - Encourages voluntary compliance - Serves as source of helpful information

16 Wisconsin H 2 S Program Effective in 1988; 240 ppb 24-hr std Structured similar to NC toxics - Conservative screening emission rates - Model if more than screening emission rates No reqts for paper mill WWTS Considering hog lagoon solutions

17 H 2 S from NC Hog Farms NC focused on ammonia and nitrogen issues - No official NC hog farm H 2 S emission data Draft EPA emission data based only on midwest farms from unpublished test - National Academy of Science criticizes EPA data as incomplete and too general - Midwest farms have dissimilar design, operations, climate and bacteria from NC farms that directly affect emissions and odors - Likely overstate NC hog H 2 S by more than 10-fold

18 DAQ Dispersion Modeling Study Modeled phosphate fertilizer and paper mill plants Assess impact area & health benefits relative to 33 ug/m 3 24-hr & 56 ug/m 3 24-hr proposed AALs Determined impact radius, i.e., distance from plant where levels more than proposed AALs Determined avg number of exceedances, i.e., typical locations within impact radius with levels more than proposed AALs

19 Table 3. Paper Mill Modeling Results Averaging period Average No. of Exceedances per year Impact Radius (km) Maximum impact (ug/m 3 ) 1-hr 56 ug/m 3 (40 ppb) 304015,311 24-hr 33 ug/m 3 (23 ppb) 22152,565

20 Table 4. Fertilizer Plant Modeling Results Averaging period Average No. of Exceedances per year Impact Radius (km) Maximum impact (ug/m 3 ) 1-hr 56 ug/m 3 (40 ppb) 45201,940 24-hr 33 ug/m 3 (23 ppb) 173054

21 H 2 S Stability in Ambient Air Generally stable 18 hrs – 3 days Extreme conditions 2 hrs – 42 days H 2 S not photochemically reactive Changes to sulfur dioxide or sulfuric acid

22 Proposed Control Technologies - Paper industry Activated sludge – biological process without chemicals to reduce H 2 S Add covers, collect and incinerate off gas Decommission settling and aeration ponds Blue Ridge Paper has activated sludge Few activated sludge units at mills

23 Figure 6. Aerial Photograph Weyerhaeuser-Plymouth

24 Figure 7. Aerial Photograph International Paper Roanoke Rapids

25

26 Proposed Control Technologies - Fertilizer industry Currently no controls Install packed bed scrubber on phosphoric acid plant point sources Use special solution to absorb H 2 S 99 + % required to marginally meet 33 ug/m 3 and 56 ug/m 3 AALs New technology for this industry


Download ppt "Engineering Assessment of Hydrogen Sulfide Issues Emission Inventory State Survey of Ambient Air Standards Regulatory Practice in Other States H 2 S from."

Similar presentations


Ads by Google