Industrial Stormwater

General Permit

ARR000000

Katherine Yarberry, PE

General Permits Engineer

Industrial Stormwater General

Permit (IGP) Stormwater discharges associated with an industrial activity

as defined in 40 CFR 122.26(b)(14)(i) – (xi) are required to

obtain coverage

Based on Standard Industrial Classification (SIC) Code

IGP Sampling Requirements All facilities required to sample under 2009 permit for basic 4

parameters: Chemical Oxygen Demand (COD), Total

Suspended Solids (TSS), Oil & Grease (O&G), and pH

IGP Sampling Requirements All facilities required to sample under 2009 permit for basic 4

parameters: Chemical Oxygen Demand (COD), Total

Suspended Solids (TSS), Oil & Grease (O&G), and pH

Some facilities have additional sampling requirements

2009 Renewal All facilities required to sample in 2009 renewal, many had

not previously had to sample (Category 0)

Due to confusion with new requirements and appeal, the

quality of the 2011 and 2012 data is higher than earlier permit

years

2014 Renewal Current IGP expires 6/30/2014

ADEQ required to issue general NPDES permits at least 6

months prior to their expiration date

Currently analyzing 2011/2012 DMR data and taking industry

commentary on the permit

Discussed Changes to Permit

DMR Data Analysis Approximately 1,946 Permittees

28 Industrial Sectors

Only 2 Unused Sectors: H (Coal Mines), Z (Leather Tanning)

406 No Exposure Exclusions

Percent within Benchmarks

For all basic 4 parameters,

the percentage of samples

complying with the

benchmarks increased from

2011 to 2012!

COD

2011 2012

86.0% 87.7%

TSS

2011 2012

76.5% 80.0%

O&G

2011 2012

98.1% 98.4%

pH

2011 2012

89.4% 92.8%

Percent within Benchmarks

The percentage of

samples meeting the

benchmarks in the

extra parameters is

high in most

categories

Percentage of permittees meeting extra parameter benchmarks in 2012

# of Samples Reported Aluminum 64.8% 426 Ammonia 100% 25 Arsenic 94.9% 78 Cadmium 100% 28 Copper 76.5% 243 Cyanide 100% 11 Iron 59.6% 627 Lead 94.9% 273 Magnesium 0% 8 Mercury 100% 8 Nitrate + Nitrite Nitrogen 60.5% 294 Phosphorus 82.8% 99 Selenium 100% 8 Silver 100% 10 Zinc 88.0% 465

Number of Exceedances

In basic 4 parameters:

Similar number of

exceedances for TSS &

O&G between 2011 & 2012

Slightly higher number of

COD exceedances in 2012

Significantly fewer pH

exceedances in 2012

COD TSS O&G pH

2011 335 560 46 254

2012 344 559 46 202

Number of Exceedances Totals

2011 2012

177 155 Aluminum

0 0 Ammonia

3 4 Arsenic

0 0 Cadmium

64 50 Copper

0 0 Cyanide

265 247 Iron

13 14 Lead

8 8 Magnesium

0 0 Mercury

95 112 Nitrate + Nitrite Nitrogen

12 10 Phosphorus

0 0 Selenium

0 0 Silver

61 58 Zinc

In additional parameters:

Lower number of

exceedances in 2012 for

Aluminum, Copper, Iron,

Phosphorus, Zinc

About the same number of

exceedances for Arsenic,

Lead, Magnesium

Higher number of

exceedances in 2012 for

Nitrate + Nitrite Nitrogen

Sampling Period Comparison

Jan-June 2012 COD TSS O&G pH

Averages 85.89 122.18 5.50 7.37

July-Dec 2012 COD TSS O&G pH

Averages 70.55 114.24 58.34 7.14

COD TSS O&G pH

z= 2.82 0.52 -0.98 1.56

Critical Z = ±1.96

95% Confidence Level

Statistical test: Are the

averages between the two

sampling periods

significantly different?

COD values are significantly

different between the two

periods

TSS, O&G, and pH values

are NOT significantly

different between the two

periods

Median Values Medians are better at

showing how the group is

doing as a whole than

averages, as they take out

the influence of outliers

2011 and 2012 median

values are all within the

benchmarks when all data is

considered

COD TSS O&G pH

2011 Median 46 31 2.8 7.07

COD TSS O&G pH

2012 Median 42 27 3.0 7.10

Median Values Only 1 Industrial Sector had

a median higher than the

benchmark for the basic 4

parameters in 2011 and

2012

Sector I is Oil & Gas

Extraction and Refining

18 permittees

2011 Medians

COD Top 5 TSS Top 5 O&G Top 5 pH Top 5

N 114 I 193 N 5.4 X 7.62

G 111 N 91 A 5 T 7.5

T 90.25 Q 89 F 5 E 7.4

A 90 K 66.5 I 5 D 7.355

K 75.95 A 60 L 5 I 7.35

2012 Medians

COD Top 5 TSS Top 5 O&G Top 5 pH Top 5

A 80 I 120 A 5 Q 8.55

T 72.5 Q 78 F 5 S 7.675

U 71 L 67 I 5 E 7.4

L 65.5 A 55.5 L 5 D 7.3

Q 61.4 R 53 Q 5 C 7.2

S 5 J 7.2

T 5 P 7.2

W 5

General Permits Contacts

Jessica Temple, EI – Engineer

501-682-0621 templej@adeq.state.ar.us

Jamal Solaimanian, PhD, PE – Engineer Supervisor

501-682-0620 jamal@adeq.state.ar.us

Submitting Applications or Reports:

water.permit.application@adeq.state.ar.us Water Division, General Permits

5301 Northshore Drive

North Little Rock, AR 72218-5317

Questions?