HomeMy WebLinkAboutA001 - Council Action Form dated February 28, 2023 ITEM #: 32
DATE: 02-28-23
DEPT: W&PC
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COUNCIL ACTION FORM
SUBJECT: INDUSTRIAL PRETREATMENT PROGAM— LOCAL LIMITS
BACKGROUND:
On March 1, 2022, the Water Pollution Control Facility (WPC) was issued a new National
Pollutant Discharge Elimination System (NPDES) permit from the Iowa Department of
Natural Resources (DNR). A requirement of the NPDES permit is to evaluate the
adequacy of the Local Limits that are established as part of the Industrial Pretreatment
Program (IPP). The goals of the IPP include protection of the Publicly Owned
Treatment Works (POTW) are: preventing discharge of pollutants to the POTW that
will inhibit treatment plant operations or pass through untreated, protecting worker
safety, and improving the ability to recycle and reclaim wastewater and biosolids.
A full reevaluation of the Local Limits was last performed in 2011 as part of the previous
NPDES permit cycle.
Staff have completed the required Local Limit evaluation using data collected from
industrial users, the WPC Facility, Iowa DNR, and the Environmental Protection Agency.
The evaluation considers several parameters for each pollutant and the parameter that
results in the Local Limit that is most protective of the POTW, worker safety, and
wastewater/biosolids quality is identified.
The table below shows the currently adopted Local Limit for each pollutant along with the
proposed Local Limit identified during the evaluation. Also noted in the table is the relative
change to the Local Limit for those pollutants with proposed changes. The proposed
Local Limits that are less restrictive are expected to allow the IPP to continue to
achieve the goals stated above. Alternatively, the proposed Local Limits that are
more restrictive are not expected to cause any industrial user to suddenly become
non-compliant with the IPP. The proposed Local Limits have been compared to past
sampling data and no exceedances by Ames' industries of the new Local Limits were
noted for the past several years.
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On February 17, 2023, staff notified all industrial users of the proposed Local Limits
revisions. Included in the letter was the plan for formally revising the Local Limits in
Chapter 28 of the Municipal Code. No responses were received.
Following Council approval, staff will submit the proposed Local Limits to the Iowa DNR
for their review in order to comply with the requirements of the NPDES permit.
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!� Current Local Proposed Local Pollutant Relative Change
Limit (mg/L) Limit (mg/L)
Ammonia 225 225 No Change
Total Kjeldahl Nitrogen 280 280 No Change
i cB0D5 1,800 1,800 No Change
COD 2,700 2,700 No Change
TSS 1,600 1,600 No Change
Acetone 14.9 16.4 Less Restrictive
Arsenic 0.02 0.03 Less Restrictive
Cadmium 0.04 0.04 No Change
i Chromium 0.93 0.95 Less.Restrictive
Copper 0.57 0.57 No Change
Cyanide 0.88 0.84 More Restrictive
Lead 0.89 0.94 Less Restrictive
j Mercury 0.01 0.01 No Change
Molybdenum 0.29 0.31 Less Restrictive
j Nickel 11.0 9.6 More Restrictive
Phenol 2.6 1.8 More Restrictive
Selenium 0.09 0.09 No Change
Silver 0.05 0.07 Less Restrictive
j Zinc 4.3 3.8 More Restrictive
j Benzene 0.05 0.05 No Change
BTEX 0.75 0.7S No Change
Total Petroleum Hydrocarbons 10.0 10.0 No Change
Sulfide 2.0 2.0 No Change
Oil & Grease 300 300 No Change
6.0-10.0 6.0-10.0
pH Standard Units Standard Units No Change
Temperature No Limit Set <.65,5 °C More Restrictive
i` Acronyms:
cBOD5 - 5-Day Carbonaceous Biochemical Oxygen Demand
COD - Chemical Oxygen Demand
TSS - Total Suspended Solids
BTEX -- Benzene, Toluene, Ethylbenzene, and Xylene
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ALTERNATIVES:
1. Approve on first reading the attached ordinance revising Chapter 28 of the
Municipal Code to amend the Industrial Pretreatment Program Local Limits.
2. Direct staff to modify the attached ordinance.
3. Do not approve the ordinance.
CITY MANAGER'S RECOMMENDED ACTION:
A full evaluation of the Local Limits is required by the Iowa Department of Natural
Resources as part of the National Pollutant Discharge Elimination System permit received
on March 1, 2022. Staff has completed the evaluation. The proposed Local Limits are
expected to allow the Industrial Pretreatment Program to meet its goals and are not
expected to cause negative consequences for industrial users. Therefore, it is the
recommendation of the City Manager that the City Council adopt Alternative No. 1, as
described above.
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ORDINANCE NO.
AN ORDINANCE TO AMEND THE MUNICIPAL CODE OF
THE CITY OF AMES,IOWA,BY AMEDNING SECTION
28.309 THEREOF,FOR THE PURPOSE OF AMENDING
PRETREATMENT LOCAL LIMITS ESTABLISHED
REPEALING ANY AND ALL ORDINANCES OR PARTS OF
ORDINANCES IN CONFLICT TO THE EXTENT OF SUCH
CONFLICT; AND ESTABLISHING AN EFFECTIVE DATE.
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BE IT ENACTED, by the City Council for the City of Ames, Iowa,that:
Section One. The Municipal Code of the City of Ames, Iowa shall be and the
same is hereby amended by amending Section 28.309, Pretreatment Local Limits
Established, as follows:
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"Sec. 28.309 Pretreatment Local Limits Established.
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Pollutant Local Limit
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(mg/L,Unless Otherwise Noted)
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Acetone 16.4 4 .-9
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i Ammonia 225
Arsenic 0.03 r,
Benzene 0.05
BTEX 0.75
Cadmium 0.04
cBODs 1,800
Copper 0.57
Chemical Oxygen Demand (COD) 2,700
Cyanide 0.84049
Lead 0.94 4.8-9
Mercury 0.01
Molybdenum 0.310,9
Nickel 9.6 44-:0
Oil & Grease 300
pH 6.0-10.0 Standard Units
Phenol 1_8 2 6
Selenium 0.09
Silver 0.07 0-.0-5
Sulfide 2.0
Temperature <65.5°C"
Total Chromium 0.95 0:9-3
Total Kjeldahl Nitrogen 280
Total Petroleum Hydrocarbons 10.0
Total Suspended Solids 1,600
Zinc 3.8473
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f Section Two. All ordinances, or parts of ordinances, in conflict herewith are
fhereby repealed to the extent of such conflict, if any.
i Section Three. This ordinance shall be in full force and effect from and after its
passage and publication as required by law.
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Passed this day of
Renee Hall, City Clerk John A. Haifa,Mayor
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