South Coast Air Quality Management District

Implementation Status of Control Measure WST-01 – Emission Reductions from Livestock Waste

SYNOPSIS: 

Proposed Rule 1127 is being developed to implement control measure WST-01 from the 1999 Amendment to the 1997 Ozone SIP. The 1999 Ozone SIP requires that PR1127 be adopted in 2002 and implemented beginning in 2004. The SIP calls for a 3.3 ton/day reduction of dairy VOC emissions by the year 2006. Control Measure WST-01 calls for reductions associated with dairy relocation and the implementation of water quality regulations to be accounted for in determining the additional control required for remaining dairies. This report documents the reductions in dairy waste VOC emissions achieved without air quality regulations and compares them to the SIP requirements.

COMMITTEE: 

Stationary Source, November 22, 2002, Reviewed

RECOMMENDED ACTION:

Receive and file.

Barry R. Wallerstein, D.Env.
Executive Officer

Background

The 1994 and 1997 Air Quality Management Plans (AQMPs) included Control Measure WST-01 – Emission Reductions from Livestock Waste. After the 1997 AQMP (which contained the 1997 Ozone SIP and 1997 PM10 SIP) was approved by the AQMD and CARB, several environmental groups sued the AQMD, CARB, and U.S. EPA for failing to implement the 1994 AQMP (Ozone SIP portion). As part of the settlement of the suit, the AQMD agreed to prepare the 1999 Amendment to the 1997 AQMP (1999 Ozone SIP). The 1999 Amendment specified that Control Measure WST-01 should be adopted by 2002, implemented beginning in 2004, and achieve 3.3 tons/day VOC emission reduction in 2010, based on the 1997/1999 AQMP baseline emissions inventory methodology.

The 1997 AQMP (PM10 SIP portion) called for a 50% reduction in ammonia and a 30% reduction in VOC. Control Measure WST-01 calls for reductions occurring from dairy cow relocation or the implementation of water quality controls with associated air quality benefits to be accounted for. Then, only those additional controls necessary to meet the emission reduction goals are to be implemented by AQMD rulemaking. VOC reductions will result from dairy cow relocation, water quality regulations and ammonia controls.

Because only the VOC portion of Control Measure WST-01 was included in the 1999 Ozone SIP commitment, this status report addresses only the VOC emissions inventory and VOC reductions. AQMD staff is in the process of preparing Proposed Rule (PR) 1127 to implement additional controls necessary to meet the ammonia emission reduction goals of Control Measure WST-01.

Urbanization pressure in the Chino Basin is causing many dairies to relocate or make plans to relocate. The land occupied by dairies and other livestock facilities in the Chino Basin were part of the Agricultural Preserve until recently. Land in the Agricultural Preserve could not be sold for non-agricultural purposes, placing a serious restriction on facilities that may prefer to relocate for other reasons. In 1997 the Agricultural Preserve designation was rescinded, allowing dairy farms to be sold for development. This is evidenced by the downward trend in the number of dairy cows, approximately 2% per year since 1997. New development in former Agricultural Preserve areas annexed by Chino and Ontario (approximately 15,600 acres) will accelerate this trend. With the reduction in dairy cows, VOC emissions from dairy waste will decrease proportionally.

In 1999, the Santa Ana Regional Water Quality Control Board (SARWQCB) adopted Order No. 99-11, "General Waste Discharge Requirements for Concentrated Animal Feeding Operations (Dairies and Related Facilities) within the Santa Ana Region." This order required, among other things, that 1) existing stockpiles on or off of dairies be removed by the end of 2002; 2) manure removed from the corrals must be removed from the dairies within 180 days and these "clean days" be reported to SARWQCB; and 3) manure can only be spread on cropland in agrometric rates and expeditiously incorporated into the soil. Dairies are also required to submit Annual Report of Animal Waste Discharge to the SARWQCB each year that includes dairy location, animal population, and manure disposal information (e.g., on-farm cropland application, manure hauled away and its destination), and any historical stockpiles that have not been removed. These water quality requirements have associated air emission reduction benefits, which are described below.

Emissions Inventory

        VOC Emission Factors for Dairy Manure
In the 1997 and 1999 AQMPs, the AQMD used an emission factor of 16 lbs VOC/head/year. There is currently controversy over the VOC emission factor used for dairy waste emissions. CARB is in the process of sponsoring additional measurement studies to resolve the controversy surrounding the dairy waste VOC emission factor, but this research will not be completed within the next year. For purposes of tracking the SIP commitment, the same emission factor of 16 lbs VOC/head/year is used.

        1997/1999 AQMP Emissions Inventory Estimates and Assumptions
The emissions estimate is calculated by multiplying the emission factor by the number of dairy cows. The emission factor discussed above is for full-grown milking cows. Unfortunately, the only cow population estimate available at that time was a total animal headcount, which included calves and heifers as well as milking cows. Some of the diary information collected by state and federal agriculture agencies was not available due to confidentiality. For the 1997 AQMP, the AQMD used a total Basin cattle count of 544,614, resulting in an emissions inventory estimate of 11.9 tons VOC/day in 1993 (a small number of cows in Coachella Valley contributed about 0.3 ton VOC/day, resulting in a district total of 12.2 tons VOC/day, as reported in the 1999 AQMP.) Growth projections in the 1997/1999 AQMP were an approximately 8% reduction in 2006 and 2010, resulting in Basin baseline emissions of 10.98 tons/day in 2006 and 2010.

        Current Emission Estimates
Recently released data by the California Department of Food and Agriculture (CDFA), shows that there were actually 285,492 milking cows in 1993 and 252,900 milking cows in 2001 (CDFA does not report heifer and calf populations). SARWQCB Annual Report data for 2001indicate that there are 68,669 heifers and 77,670 calves in 2001. (It should be noted that SARWQCB data from adult cows in 2001 was 241,000.) Thus the total animal population in 2001 is 399,239.

As noted above, a USDA estimate of heifers and calves was included in the animal population used in the 1997/1999 AQMP. Although there is no established VOC emission factor for heifers and calves, for the purpose of this analysis and consistent with the 1997/1999 AQMP assumptions, it is assumed that calves and heifers have the same emission factor (16 lbs/cow/year) as adult cows. Base on these assumptions and reported animal population, the 2001 emission estimate is 8.75 tons/day VOC.

As noted in the 1997/1999 AQMP, increased urbanization is resulting in the relocation of dairies from the Chino area to outside of the Basin. With the completion of development plans for dairy areas annexed by Chino and Ontario, this trend has accelerated in recent years. Industry sources believe that ultimately 50% of the local dairies will relocate, with the rest remaining in current dairy lands that cannot be developed or in the San Jacinto area. The latest historical trend is that the dairy cow population will drop at 2% per year, starting in 2001and until it reaches a final value of approximately 50% of 1993 levels in 2020. (The Inland Empire Utilities Agency calculates a 3% per year reduction, with an overall reduction of 50% by 2015.)

Impact of New Water Quality Regulations

The new water quality regulations (SARWQCB Order No. 99-11) expedite manure removal from dairies, limits and sets manure incorporation standards for land spreading of manure, and eliminates historical stockpiles of manure in and around the dairies. Because these regulations affect manure, the VOC emissions per ton of manure must be calculated to assess the emission reductions associated with the water quality regulations. Manure productions is known from the SARWQCB’s Annual Report of Animal Waste Discharge. The VOC emissions factor per ton of manure is based on yearly VOC emissions for all adult cows divided by the overall manure production. The VOC emission factor is 0.0015 tons per ton of manure.

The estimated impact of removing historical stockpiles is calculated by multiplying the tons of historical stockpiles that have been removed (94,000 tons, according to the SARWQCB) by the VOC emissions factor per ton of manure. The net air quality impact is the removal of 0.39 tons VOC/day in 2001.

The estimated impact of the land application regulations (e.g., agrometric spreading rates, expeditious soil incorporation) is a 23% reduction in emissions multiplied by 0.5, since the reductions only occur after the manure is removed the dairies, which occurs twice a year. Thus, the overall reduction effectiveness of the new land spreading regulations in 11.5% of the manure produced that is land applied in the Basin. 812,957 tons of manure was land applied in 2001, based on SARWQB data.

Also in response to current and proposed water quality regulations, manure composting operations were begun in 1995. These operations process over 200,000 tons of manure per year. Based on flux results of the 1995 PM10 Technical Enhancement Program (PTEP) studies of dairy and open-windrow composting operations, emissions are 75% less at the composting operations compared to manure emissions at the dairy. Reductions from composting can only occur after the manure is removed from the dairy (twice a year), so again, the control effectiveness is multiplied by 0.5. Thus, the overall reduction effectiveness is 37.5% for manure that is composted in open windrows and near 50% for enclosed and controlled composting facilities. 266,379 tons of manure was composted in open windrows in 2001.

In response to the water quality regulations and the energy crises, anaerobic digesters have been constructed and are currently operating. These digesters create "biogas" used as fuel for power generation equipment. The remaining digested solids are finished or near finished compost. The digester essentially eliminates VOC emission from the manure as anaerobic bacteria convert organic matter to biogas. Also, digesters require the freshest possible manure. Current digester programs scrape the feedlanes at the dairies daily and immediately transport it to the digesters. Since all the manure emissions are gone immediately (rather than waiting the 180 days until the corral is cleared), the removal factor is 1.0. Thus, the overall control effectiveness for manure sent to a digester is 100%. Demonstration projects for anaerobic digesters began in 2002, but only small amounts of manure were digested in 2002.

Of course, any manure sent out of the Basin does not contribute emissions within the airshed. Multiplied by the 0.5 factor to account for the manure’s presence in the first 180 days, the overall effectiveness of removing manure from the Basin is 50%. 213,330 tons (about 16%) of manure was shipped out of the Basin (generally to San Joaquin Valley and Imperial County), based on 2001 SARWQCB data.

Summary of Emission Reductions – 2010 Planning

As noted above, the total dairy-related animal population used in the 1997/1999 AQMP was 544,614, resulting in 11.94 tons/day of VOC (Basin only). Based on current information, the total dairy-related animal population in 2001 was 399,239. Using the 1997/1999 AQMP emission factors for cows, heifers and calves, the current estimate of 2001 Basin emissions is 8.75 tons/day of VOC. This table summarize the calculation of Basin emissions and emission reductions using the 1997/1999 AQMP baseline methodology and current animal population information.
 

Conclusions and Recommendations

As shown above, emission reductions from animal relocation and the enhanced water quality regulations is 4.23 tons/day in 2006 and 4.82 tons/day in 2010. Thus, even in the absence of future rulemaking, the SIP commitment of 3.3 tons/day of VOC reductions will be achieved. Even if dairy relocation were to stop, analysis of the current 2001 emissions demonstrate achievement of the SIP target for all future years. (8.75 tons/day of VOC minus 1.25 ton/day of reductions from enhanced water quality regulations results in 7.5 tons/day remaining VOC emissions. Compared to the 1997/1999AQMP baseline of 10.98 tons/day, emission reductions are 3.48 tons/day.) PR1127 is expected to result in additional VOC reductions because additional controls are necessary to meet the ammonia emission reduction target in Control Measure WST-01. PR1127 is currently scheduled for Governing Board consideration on March 7, 2003.

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