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Subpart U—Standards of Performance for the Phosphate Fertilizer 

Industry: Superphosphoric Acid Plants

§ 60.210 Applicability and designation of affected facility.

(a) The affected facility to which the provisions of this 

subpart apply is each superphosphoric acid plant having a design 

capacity of more than 15 tons of equivalent P2O5 feed per 

calendar day. For the purpose of this subpart, the affected 

facility includes any combination of: evaporators, hot wells, 

acid sumps, and cooling tanks.

(b) Any facility under paragraph (a) of this section that 

commences construction or modification after October 22, 1974, 

is subject to the requirements of this subpart.

§ 60.211 Definitions.

As used in this subpart, all terms not defined herein shall 

have the meaning given them in the Act and in subpart A of this 

part. 

(a) Superphosphoric acid plant means any facility which 

concentrates wet-process phosphoric acid to 66 percent or 

greater P2O5 content by weight for eventual consumption as a 

fertilizer. A superphosphoric acid plant includes, but is not 

limited to: evaporators, hot wells, acid sumps, oxidation 

reactors, and cooling tanks.
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(b) Total fluorides means elemental fluorine and all 

fluoride compounds as measured by reference methods specified in 

§ 60.214, or equivalent or alternative methods. 

(c) Equivalent P2O5 feed means the quantity of phosphorus, 

expressed as phosphorus pentoxide, fed to the process.

§ 60.212 Standard for fluorides.

(a) On and after the date on which the performance test 

required to be conducted by § 60.8 is completed, no owner or 

operator subject to the provisions of this subpart shall cause 

to be discharged into the atmosphere from any affected facility 

any gases which contain total fluorides in excess of 5.0 

g/megagram (Mg) of equivalent P2O5 feed (0.010 lb/ton).

§ 60.213 Monitoring of operations.

(a) The owner or operator of any superphosphoric acid plant 

subject to the provisions of this subpart shall install, 

calibrate, maintain, and operate a flow monitoring device which 

can be used to determine the mass flow of phosphorus-bearing 

feed material to the process. The flow monitoring device shall 

have an accuracy of ±5 percent over its operating range. 

(b) The owner or operator of any superphosphoric acid plant 

shall maintain a daily record of equivalent P2O5 feed by first 

determining the total mass rate in Mg/hr of phosphorus-bearing 

feed using a flow monitoring device meeting the requirements of 
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paragraph (a) of this section and then by proceeding according 

to § 60.214(b)(3). 

(c) Except as specified in paragraph (d) of this section, 

tThe owner or operator of any superphosphoric acid plant subject 

to the provisions of this part shall install, calibrate, 

maintain, and operate a monitoring device which continuously 

measures and permanently records the total pressure drop across 

the process scrubbing system absorber. The monitoring device 

shall have an accuracy of ±5 percent over its operating range.

(d) Any affected facility as defined in § 60.210(a) that 

commences construction, modification or reconstruction after 

[date of publication of the final rule in the Federal Register] 

is subject to the requirements of this paragraph instead of the 

requirements in paragraph (c) of this section. If an absorber is 

used to comply with § 60.212, then the owner or operator shall 

continuously monitor pressure drop through the absorber and meet 

the requirements specified in paragraphs (d)(1) through (d)(4) 

of this section.

(1) The owner or operator shall install, calibrate,

maintain, and operate a continuous monitoring system (CMS) that 

continuously measures and permanently records the pressure at 

the gas stream inlet and outlet of the absorber. The pressure at 

the gas stream inlet of the absorber may be measured using 
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amperage on the blower if a correlation between pressure and 

amperage is established.

(2) The CMS must have an accuracy of ± 5 percent over the 

normal range measured or 0.12 kilopascals (0.5 inches of water 

column), whichever is greater.

(3) The owner or operator shall establish an allowable 

range for the pressure drop through the absorber. The allowable 

range is ±20 percent of the arithmetic average of the three test 

runs conducted during the performance test required in § 60.8. 

The Administrator retains the right to reduce the ±20 percent 

adjustment to the baseline average values of operating ranges in 

those instances where performance test results indicate that a 

source's level of emissions is near the value of an applicable 

emissions standard. However, the adjustment must not be reduced 

to less than ±10 percent under any instance.

(4) The owner or operator shall demonstrate continuous 

compliance by maintaining the daily average pressure drop 

through the absorber to within the allowable range established 

in paragraph (d)(3) of this section. The daily average pressure 

drop through the absorber for each operating day shall be 

calculated using the data recorded by the monitoring system. If 

the emissions unit operation is continuous, the operating day is 

a 24-hour period. If the emissions unit operation is not 

continuous, the operating day is the total number of hours of 
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control device operation per 24-hour period. Valid data points 

must be available for 75 percent of the operating hours in an 

operating day to compute the daily average.

§ 60.214 Test methods and procedures.

(a) In conducting the performance tests required in § 60.8, 

the owner or operator shall use as reference methods and 

procedures the test methods in appendix A of this part or other 

methods and procedures as specified in this section, except as 

provided in § 60.8(b).

(b) The owner or operator shall determine compliance with 

the total fluorides standard in § 60.212 as follows:

(1) The emission rate (E) of total fluorides shall be 

computed for each run using the following equation:

where:

E = emission rate of total fluorides, g/Mg (lb/ton) of 

equivalent P2O5 feed.

Csi = concentration of total fluorides from emission point 

“i,” mg/dscm (gr/dscf).

Qsdi = volumetric flow rate of effluent gas from emission 

point “i,” dscm/hr (dscf/hr).

N = number of emission points associated with the 

affected facility.

P = equivalent P2O5 feed rate, Mg/hr (ton/hr).

K = conversion factor, 1000 mg/g (7,000 gr/lb).
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(2) Method 13A or 13B shall be used to determine the total 

fluorides concentration (Csi) and volumetric flow rate (Qsdi) of 

the effluent gas from each of the emission points. The sampling 

time and sample volume for each run shall be at least 60 minutes 

and 0.85 dscm (30 dscf). 

(3) The equivalent P2O5 feed rate (P) shall be computed for 

each run using the following equation:

P=Mp Rp

where:

Mp = total mass flow rate of phosphorus-bearing feed, 

Mg/hr (ton/hr).

Rp = P2O5 content, decimal fraction.

(i) The accountability system of § 60.213(a) shall be used 

to determine the mass flow rate (Mp) of the phosphorus-bearing 

feed. 

(ii) The Association of Official Analytical Chemists (AOAC) 

Method 9 (incorporated by reference—see § 60.17) shall be used 

to determine the P2O5 content (Rp) of the feed.

§ 60.215 Recordkeeping.

An affected facility as defined in § 60.210(a) that 

commences construction, modification, or reconstruction after 

[date of publication of the final rule in the Federal Register] 

is subject to the requirements of this section. You must 

maintain the records identified as specified in § 60.7(f) and in 
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paragraphs (a) and (b) of this section. All records required by 

this subpart must be maintained on site for at least 5 years.

(a) Records of the daily average pressure drop through the 

absorber.

(b) Records of deviations. A deviation is determined to 

have occurred when the monitoring data or lack of monitoring 

data result in any one of the criteria specified in paragraphs 

(b)(1) and (b)(2) of this section being met.

(1) A deviation occurs when the daily average value of a 

monitored operating parameter is less than the minimum pressure 

drop, or greater than the maximum pressure drop established in § 

60.213(d)(3).

(2) A deviation occurs when the monitoring data are not 

available for at least 75 percent of the operating hours in a 

day.