HomeMy WebLinkAbout3070 Ordinance, V
i
ORDINANCE NO 3o70
AN ORDINANCE concerning the carrying out of a system or plan for
additions and betterments to and extensions of the water works utility of the
City, the modification of effluent flow characteristics as identified in the
facility plan, amending the facility plan, and amending Ordinance No 3040
WHEREAS, on August 15, 1994 the City Council approved Ordinance
No 3040, an Ordinance relating to the water works utility of the City,
specifying, adopting and ordering the carrying out of a system or plan for
additions and betterments to the extensions of the water works utility of the
City, authorizing the issuance of water and sewer revenue bonds in the
amount of up to eight million five hundred twenty thousand dollars
($8,520,000 00) to obtain a part of the funds with which to pay the costs of
carrying out a portion of that system or plan, authorizing the issuance of a
three million dollar ($3,000,000 00) par value water and sewer revenue bond
anticipation note pending the issuance of the bond, fixing the date, interest
rates, form, maturity, terms, covenants and uses of the proceeds of those
bonds, creating a special note redemption fund and a construction fund, and
providing for the sale and delivery of the note to West One Bank,
Washington, of Seattle, Washington, and
WHEREAS, in order to settle an existing dispute with the Washington
State Department of Ecology over the conditions required in a National
Pollution Discharge Elimination System (NPDES) permit for the City and its
Wastewater Treatment Facilities, the City has agreed to amend the plan of
additions and betterments to and extensions of the waterworks utility of the
City described in Exhibit "A" to Ordinance No 3040, which exhibit in part
provides for the modification of effluent flow characteristics of the City's
Wastewater Treatment Facilities, now, therefore,
THE CITY COUNCIL OF THE CITY OF PASCO, WASHINGTON DO
ORDAIN AS FOLLOWS:
§1. That Ordinance No 3040 adopted by the City Council on August 15,
1994 is hereby amended only to the extent that the system or plan of additions
and betterments to and extensions of the waterworks utility of the City
described in Exhibit "A" attached thereto and adopted by Section 1 of said
Ordinance, is hereby amended by the exhibit attached hereto titled CITY OF
PASCO, WASTEWATER FACILITIES PROJECT, DESIGN MEMORANDUM
NO 1, MODIFICATION OF EFFLUENT CHARACTERISTICS AS IDENTIFIED
IN THE FACILITY PLAN by HDR Engineering, Inc , December, 1994
Ordinance No 5 6‘761Page 1 of 2
Appr ved As To
§2. This Ordinance shall take effect five (5) days after passage and
publication
Passed by the City Council of the City of Pasco, at a regular meeting this
19th day of December, 1994
City of Pasco.
Attest.
Catherine D Seaman
Deputy City Clerk
G eg A Rubstello
Ci torney
Ordinance No 30-2c9 Page 2 of 2
-
CITY OF PASCO
WASTEWATER FACILITIES PROJECT
DESIGN MEMORANDUM NO. 1
MODIFICATION OF EFFLUENT
FLOW CHARACTERISTICS
AS IDENTIFIED lay
THE FACILITY PLAN
1 EXPIRES 5 / 31 / CX0 I
HDR ENGINEERING, INC.
DECEMBER, 1994
This Design Memorandum No 1 dated December 1994 has been prepared by, or under the direct
supervision of, Anthony H Krutsch, Professional Engineer, WA #0024807
i
DESIGN MEMORANDUM NO. 1
CITY OF PASCO WASTEWATER FACILITIES PROJECT
SUMMARY
The purpose of this Design Memorandum is to identify and clarify the effluent wastewater
characteristics to be expected at the City of Pasco Wastewater Treatment Plant in the design year
2005, and to amend certain provisions of the City's adopted Facility Plan
FINDINGS
1 The influent design conditions for the year 2005 included in the Facility Plan were
conservative and resulted in higher influent concentrations of BOD and TSS than is
characteristic of the City's current influent conditions
2 In calculation of total poundage effluent limits for BOD and TSS in the City's NPDES
permit, the WDOE applied a flow discharge standard in combination with the conservative
influent concentrations m the Facility Plan resulting m exceedingly high efficiency
standards for BOD and TSS removal (89 8 percent BOD, 87 5 percent TSS) for the City's
proposed improvements at their wastewater treatment plant
3 To resolve the appeal of the City of Pasco regarding the issuance of the NPDES and the
total poundage limits for BOD and TSS, the City has proposed that the effluent limits for
the design year 2005 be based -on the characteristics of the City's current influent
conditions Further, the City has agreed that in calculation of a total poundage limit for
BOD and TSS, the WDOE may use the revised influent flow for the design year 2005 of
4 52 mgd for maximum month average daily conditions
4 In adopting total poundage effluent limits for BOD and TSS, the City of Pasco recognizes
these limits as design limitations and not total maximum daily loads as may be calculated
by WDOE based on a water quality assessment and water quality basin plan for the
Columbia River
RECOMMENDATIONS
1 The Facility Plan is modified to revise effluent wastewater characteristics for the design
year 2005 as set forth in this Design Memorandum to reflect actual existing influent
wastewater characteristics
2 The NPDES effluent limitations will be revised to conform with the revised influent
wastewater characteristics for the design year 2005 as set forth in the following Table A
pasco\desgnmem rpt 1
TABLE A
CITY OF PASCO
REVISED NPDES PERMIT LIMITATIONS
DECEMBER 1994
EFFLUENT LIMITATIONS'
Parameter Monthly Average Weekly Average
Biochemical Oxygen
Demand b (5-day) 30 mg/1 1130 lbs/dayc 45 mg/1 1695 lbs/day`
Total Suspended Solids" 30 mg/1 1130 lbs/dayc 45 mg/I 1695 lbs/dayc
Fecal Conform Bacteria 200/100 ml 400/100 ml
pH shall not be outside the range 6 0 to 9 0
Monthly Average Daily Maximum
Total Ammonia (as NH 3 -N) 8 3 mg/1 19 0 mg/1
aThe monthly and weekly averages are based on the arithmetic mean of the samples taken with the exception of fecal
conform, which is based on the geometric mean
b The monthly average effluent concentration for BOD, and Total Suspended Solids shall not exceed 30 mg/1 or 85
percent removal of the respective monthly average influent concentrations, whichever is more stringent
'Total poundage limits are based on a design flow rate for maximum monthly average daily flow of 4 52 mgd
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DESIGN MEMORANDUM NO 1
CITY OF PASCO WASTEWATER FACILITIES PROJECT
INTRODUCTION
The City of Pasco is undertaking a major expansion of its wastewater treatment facilities,
interceptor sewer system, and pumping stations HDR Engineering, Inc has been selected by the
City to guide the wastewater treatment facilities project through the final planrung stages, detailed
design, and construction This Design Memorandum No 1 describes and clarifies certain issues
relating to the proposed wastewater treatment plant improvements and the City's adoption of the
Wastewater Facilities Plan dated June 1993 and the Supplemental Facility Plan dated February
1994
STATEMENT OF PROBLEM
In February 1994, the City of Pasco received a new NPDES permit from the Washington
Department of Ecology (WDOE) Following it's issuance, the City appealed certain provisions
of the permit and particularly the provision regarding total poundage limits for monthly average
and weekly average discharge of Biochemical Oxygen Demand (BUD) and Total Suspended
Solids (TSS) for the new wastewater treatment plant, as proposed by the City of Pasco in their
Facility Plan Table 1-1 identifies the Effluent Limitations as contained in the NPDES permit
in February 1994
i
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TABLE 1-1
CITY OF PASCO
NPDES PERMIT LIMITATIONS
FEBRUARY 1994
EFFLUENT LIMITATIONS'
Parameter Monthly Average Weekly Average
Biochemical Oxygen
Demand') (5-day) 30 mg/I 916 lbs/day 45 mg/I 1374 lbs/day
Total Suspended Solids b 30 mg/1 916 lbs/day 45 mg/1 1374 lbs/day
Fecal Conform Bacteria _ 200/100 ml 400/100 ml
pH shall not be outside the range 6 0 to 9 0
Monthly Average Daily Maximum
Total Ammonia (as NH 3 -N) 8 3 mg/L 19 0 mg/L
aThe monthly and weekly averages are based on the arithmetic mean of the samples taken with the exception of fecal
coliform, which is based on the geometric mean
b The monthly average effluent concentration for BOD, and Total Suspended Solids shall not exceed 30 mg/I or 85
percent removal of the respective monthly average influent concentrations, whichever is more stringent
WDOE had calculated the total pound limits for BOD and TSS based on information contained
in the City's Facility Plan relating to the expected wastewater influent flow and loadings (le
influent wastewater characteristics) Table 1-2 is taken from Chapter 5 of the Facility Plan and
identifies the expected population to be served and the expected wastewater loadings as contained
therein
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TABLE 1-2
CITY OF PASCO
WASTEWATER TREATMENT PLANT
PROJECTED POPULATIONS SERVED AND WASTEWATER LOADINGS
Criteria 1990' 1995 2000 2005 2010 N/A 2
Population 20,340 23,750 28,200 33,500 39,800 55,770
Population Equivalent 26,410 30,840 36,620 43,500 51,680 72,420
Population @ Mm Flow 18,470 - 21,530 25,580 30,370 36,090 50,600
Avg Annual Flow, MGD 2 30 2 68 3 19 3 79 4 50 6 30
Max Month Flow, MGD 2 64 3 09 3 66 4 35 5 17 724
Max Mo
@Min Flow,MGD
222 258 307 364 433 607
,
Max Day Flow,MGD 2 99 3 49 4 14 4 92 5 85 8 19
Max Hour Flow,MGD 5 06 5 90 7 01 8 33 9 89 13 86
Avg Annual BOD,ppd 4,480 5,230 6,200 7,370 8,760 12,170
Max Month BOD,ppd 6,500 7,580 9,000 10,690 12,700 17,790
Max Mo @Min Flow,ppd 6,500 7,580 9,000 10,690 12,700 17,790
Winter Avg BOD,ppd 4,070 4,750 5,64-0 6,700 7,900 11,150
Winter Max Mo BOD,ppd 5,300 6,180 7,330 8,710 10,350 14,500
Win Max Mo @Mm Flow
BOD,ppd 5,300 6,180 7,330 8,710 10,350 14,500
Avg Annual TSS,ppd 3,870 4,510 5,360 6,370 7,560 10,600
Max Month TSS,ppd 5,300 6,180 7,340 8,720 10,360 14,520
Max Mo @Min Flow,ppd 5,300 6,180 7,340 8,720 10,360 14,520
Winter Avg TSS,ppd 3,050 3,560 4,230 5,030 5,970 8,370
Winter Max Mo TSS,ppd 3,970 4,630 5,500 6,530 7,760 10,880
Win Max Mo @Min Flow
TSS,ppd 3,970 4,630 5,500 _ 6,530 7,760 10,880
'Column added for clarity
2 Column identifies desired design conditions upon completion of Phase II construction (Approx 2018)
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The projected population and influent wastewater loadings were taken directly from the
Comprehensive Sewer Plan prepared by Rust Engineering, Inc in October 1993 The
Comprehensive Sewer Plan had analyzed wastewater flow and loadings from 1985 through 1990
to develop existing influent wastewater characteristics
In appealing the NPDES permit, the City's initial position was that a total pound effluent limit
for BOD and TSS need not be included in the permit as the wastewater effluent was already
limited to total pounds by provisions of the Washington Administrative Code (WAC 173-221)
which establishes "Discharge Standards and Effluent Limitations for Domestic Wastewater
Facilities" Under WAC 173-221-040(1), wastewater facility discharge standards are defined as
follows
" shall not exceed a thirty-day average of 30 milligrams per liter (30 mg/L) BOD, 30
mg/L TSS Seven-day averages shall not exceed 45 mg/L BUD, 45 mg/L TSS
Additionally, the thirty-day average percent removals of BUD and TSS shall not be less
than eighty-five percent of influent concentrations"
In this case, it was the City's position that the total poundage effluent limit for BUD and TSS
was an operational parameter under the discharge standards rather than a fixed limit As neither
influent or effluent flow is descnbed as a regulated discharge standard in WAC 173-221-040, the
City further contended that flow rate should not be regulated
The WDOE insisted that a total poundage effluent limit should be included in the permit and
contended that the effluent flow must be included in the calculation of total poundage limits for
BOD and TSS In using flow in the calculation of a_total poundage limit, WDOE would
therefore add flow as a regulated discharge standard
The City further contended that if a total poundage effluent limit were to be included in the
NPDES permit, it should be set based on the parameters which were regulated In this case, the
total poundage limit would be based on 15 percent of expected influent BUD and TSS loadings
as regulated under WAC 173-221
Table 1-3 identifies the difference between the total poundage effluent limits for BUD and TSS
based on the wastewater flows and loadings set forth in Table 1-2, and using the WDOE and City
methods of calculation of poundage limits
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TABLE 1-3
CITY OF PASCO
POUNDAGE LIMITS FOR BOD AND TSS
WDOE AND CITY METHODS
Parameter WAC 173-221 WDOE 1 City'
BOD 30 mg/L
85% removal
1088 2
1604'
TSS 30 mg/L
85% removal
1088 2
1308 3
'Based on 2005 design conditions in Table 1-2
2 30 mWL (mass limit) x 4 35 mgd (flow rate)
3 15 percent of influent parameter
With the total poundage effluent limits proposed by WDOE, the City's new wastewater treatment
facilities would be required to remove 89 8 percent of influent BOD concentration, and 87 5
percent of influent TSS concentration
After nearly 9 months of working with WDOE, the City has been successful in resolving many
of the issues included in the appeal The total pound effluent limits for BOD and TSS appeared
to be the last remaining item to full resolution of this issue
PROPOSED RESOLUTION OF THE PROBLEM
The City requested that the influent wastewater loading rates for the existing wastewater treatment
plant be reviewed in a effort to find an equitable solution to this matter A copy of a November
16, 1994 letter report to Ms Lisa Olson, WDOE, is included in Appendix A to this report which
analyzes influent wastewater parameters for the existing wastewater plant from January 1990
through December 1993
Based on this review of existing influent wastewater loading rates, it is apparent that the
Comprehensive Sewer Plan utilized a generally pessimistic approach to the identification of
influent BOD wastewater characteristics for the Pasco facility A pessimistic approach is
appropriate when looking at the design of a facility to meet an unsure future condition When
the numbers generated in the pessimistic approach are used by the WDOE to develop effluent
limits however, the piggy-backing of the pessimistic approach and application of the WDOE
conservative factors leads to ultra-conservative NPDES permit provisions
Based on the current evaluation of the influent wastewater loading conditions, the following
modifications to the Facility Plan are proposed
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Chapter 5, Page V-3, Table V-2
This table is revised as follows Numbers shown in parentheses are those in the Comprehensive
Sewer Plan and Facility Plan
TABLE V-2
CITY OF PASCO
WASTEWATER TREATMENT PLANT
EXISTING PER CAPITA LOADING
Parameter
Annual
Capita
Maximum
Month
Capita
Maximum
Day
Capita
Maximum
Hour
Capita
Flow, gpd _ 115 (113) 135 (130) 165 (147) 260 (249)
BOD, ppd _ 020 (022) 0 24 (0 32)
Winter BOD, ppd 0 20 (0 20) 0 24 (0 26)
TSS, ppd 0 20(0 19) 025 (026)
Winter TSS, ppd 0 17 (0 15) 0 23 (0 20)
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Chapter 5, Page V-7, Table V-5
This table is revised as follows Numbers shown in parentheses are those in the Facility Plan
TABLE V-5
CITY OF PASCO
WASTEWATER TREATMENT PLANT
PROJECTED POPULATION AND WASTEWATER LOADINGS
Criteria 1990 1 2000 2005 2010 2018
Population 20,340 28,200 33,500 39,800 55,770
Avg Annual Flow, MGD 2 34 (2 30) 3 24 (3 19) 3 85 (3 79) 4 58 (4 50) 641 (6 30)
Max Month Flow, MGD 275 (264) 3 81(3 66) 452 (435) 5 37 (5 17) 753 (724)
Max Daily Flow, MOD 3 36 (299) 465 (4 14) 5 53 (492) 6 57 (5 85) 920 (8 19)
Max Hour Flow, MOD 5 29 (5 06) 733 (701) 8 71 (8 33) 10 35 (9 89) 14 50 (13 86)
Avg Annual BOD, ppd 4068 (4480) 5640 (6200) , 6700 (7370) 7960 (8760) 11,154 (12,170)
Max Month BOD, ppd 4882 (6500) 6768 (9000) 8040 (10,690) 9552 (12,700) 13,385 (17,790)
Winter Avg BOD, ppd 4068 (4070) 5640 (5640) 6700 (6700) 7960 (7960) 11,154 (11,150)
Winter Max Mo BOD, ppd 4882 (5300) 6768 (7330) 8040 (8710) 9552 (10,350) 13,385 (14,500)
Avg Annual TSS, ppd 4068 (3870) 5640 (5360) 6700 (6370) 7960 (7560) 11,154 (10,600)
Max Month TSS, ppd 5085 (5300) 7050 (7340) 8375 (8720) 9950 (10,360) 13,943 (14,520)
Winter Avg TSS, ppd 3458 (3050) 4794 (4230) 5695 (5030) 6766 (5970) 9481 (8370)
Winter Max Mo TSS, ppd 4678 (3970) 6486 (5500) 7705 (6530) 9154 (7760) 12,827 (10,880)
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Chapter 5, Page V-9, Table V-6
This table is revised as follows
TABLE V-6
CITY OF PASCO
WASTEWATER TREATMENT PLANT
ANTICIPATED PERMIT LIMITS
Parameter
2005 Effluent 2018 Effluent
Monthly Avg Weekly Avg Monthly Avg Weekly Avg
Wastewater
Flow'
452 MGD 753 MGD
BOD (5 day)
concentration
30 mg/L 45 mg/L 30 mg/L 45 mg/L
BOD, mass
emissions 2
1206 ppd 1809 ppd 2008 ppd 3012 ppd
BOD, mass
emission ] _
1130 ppd4 1695 ppd 1884 ppd4 2826 ppd
TSS
concentration
30 mg/L 45 meL 30 meL 45 mg/L
TSS, mass
emissions 7
1256 ppd 1884 ppd 2091 ppd 3137 ppd
TSS, mass
emissions 8
1130 ppd7 1695 ppd 1884 ppd9 2826 ppd
Fecal Coliforrn 200/100 mL 400/100 mL 200/100 mL 400/100 rnL
pH 6 0 - 9 0 6 0 - 9 0 6 0 - 9 0 6 0 - 9 0
i Based on Max Month Flow
2 Based on 85% removal of Max Month BOD
3 Based on 30 mg/L in effluent at Max Month Flow
4 Translates to 89 4% removal dunng Max Month Flow
5 Based on 85% removal of Max Month TSS
6 Based on 30 mg/L in effluent at Max Month Flow
7 Translates to 87 0% removal during Max Month Flow
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IMPACTS OF MODIFICATIONS OF INFLUENT WASTEWATER CHARACTERISTICS
ON THE PROPOSED WASTEWATER TREATMENT FACILITIES
The following impacts to the proposed wastewater treatment facilities have been identified as the
result of the modifications to the Facility Plan— -
1 The hydraulic capacity of the treatment facilities will be increased by approximately 10
percent
2 The trickling filter will be loaded at a lower rate than previously anticipated The need
to replace the rock media with plastic media can be delayed until after the year 2005
Modifications to the trickling filter pumping station and trickling filter mechanism are
required
3 The BOD and ammonia loading to the activated sludge system will remain approximately
as stated in the Facility Plan BOD loading to the activated sludge system is based on
the removal efficiency of the trickling filter which is reduced with rock versus plastic
media Ammonia loading to the activated sludge system is based on population served
which is unaffected by this revision to the Facility Plan
4 Aeration basin sizing and blower capacity for the activated sludge system is unchanged
by this modification
5 The RAS pumping equipment will be slightly increased to meet the increased hydraulic
capacity of the treatment facilities .. _
6 The overflow rate of the secondary clarifiers will be slightly higher than previously
anticipated No increase in size of the secondary clarifiers is anticipated
7 The UV disinfection equipment will be increased to meet the increased hydraulic capacity
of the treatment facilities
With respect to capital and operations and maintenance costs of the wastewater treatment plant
resulting from this modification to the Facility Plan, the following impacts have been identified
1 Delaying replacement of the rock media until after the year 2005 will reduce initial
construction costs by $403,000
2 The hydraulic capacity_increase of approximately 10 percent will result in slightly higher
costs associated with electrical usage and chemical consumption at the treatment plant
The increased costs for design year 2005 are estimated at $1000 per year
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APPENDIX A
CITY OF PASCO
WASTEWATER FACILITIES PROJECT
HDR ENGINEERING, INC.
LETTER TO WDOE
DATED NOVEMBER 16, 1994
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F Ps-) I t A i„, V54- 4-- (5 0")--) 45(0 - (0 1 15
1 95 cl-
November 16, 1994
07568-005-002-10
Ms Lisa Lisa M Olson
Water Quality Section
Eastern Regional Office
Washington Department of Ecology
N 4601 Monroe, Suite 100
Spokane, WA 99205-1295
Subject City of Pasco NPDES Permit
Total Pound Limits for BOD and TSS
Dear Lisa
It appears as if the City's and WDOE's attorneys have resolved the majonty of issues relating
to the City of Pasco's appeal of the NPDES permit The last remaining issue relates to the
calculation of the total poundage limits for BOD and TSS In trying to resolve this matter,
we have prepared the following re-evaluation of the wastewater flow and loadings that were
included in the Comprehensive Sewer Plan prepared by Rust Engmeenng, Inc for your
consideration
EXISTING WASTEWATER CHARACTERISTICS
The Comprehensive Sewer Plan analyzed wastewater flow and loadings from 1985 through
1990 to develop existmg wastewater charactenstics Table 1 identifies operatmg conditions
for the existing wastewater treatment plant which was updated by HDR Engmeenng, Inc in
1993 to reflect the plant operating data for 1991 and 1992
P 0 Box 808
Pasco Washington
99301 0808
HDR Engineering, Inc
TABLE 1
CITY OF PASCO
WASTEWATER TREATMENT PLANT
EXISTING WASTEWATER LOADING RATES'
Parameter Average
Annual
Maximum
Month
Maximum
Day
Maximum
Hour
Flow, MGD 2 30 2 64 2 99 5 06
BOD, ppd 4,480 6,500
Winter BOD, ppd 4,070 5,300
TSS, ppd 3,870 5,300'
Winter TSS, ppd 3,050 3,970
1 Table IV 3 1, Comprehensive Sewer Plan, October 1992
2 Based on review of 1991 and 1992 operating data Comprehensive Sewer Plan used
4640
With the current controversy concerrung the NPDES permit limitations for BOD and TSS, we
have revisited the issue of wastewater loading rates for the existing wastewater treatment plant
as shown in Table 2 and Figures 1 through 11 Generally, we have concluded that
1 The Comprehensive Sewer Plan identified a maximum month BUD loading of
6,500 ppd whereas the 1990-1993 records identified only 5,240 ppd (October
1993) The Comprehensive Sewer Plan appears to have over-estimated
maximum month BUD loading for the existing wastewater treatment plant
2 The Comprehensive Sewer Plan identified a maximum month TSS loading of
4,640 whereas the 1990-1993 records identified 5,332 ppd (April 1992) The
Comprehensive Sewer Plan appears to have under-estimated maximum month
TSS loading for the existing wastewater treatment plant
3 The Comprehensive Sewer Plan identified a maximum month winter BUD
loading of 5,300 ppd whereas the 1990-1993 records identified only 5,240 ppd
(October 1993) The Comprehensive Sewer Plan appears to have over-estimated
maximum month winter BUD
4 The Comprehensive Sewer Plan identified a maximum month winter TSS
loading of 3,970 ppd whereas the 1990-1993 records identified 4,814 ppd
(November 1991) The Comprehensive Sewer Plan appears to have under-
estimated maximum month winter TSS
5 The Comprehensive Sewer Plan identified a maximum month flow of 2 64 mgd
whereas the 1990-1993 records identified 2 862 mgd (July 1992) Maximum
month flow conditions do not necessarily correspond to maximum month BOD
and/or TSS loadings
6 The Comprehensive Sewer Plan identified the average annual flow at 2 30 mgd
whereas the 1990-1993 records identify the average annual flow at 2 474 mgd
(Increased flow factor of 1 0757 from the Comprehensive Sewer Plan)
7 The Comprehensive Sewer Plan identified the average annual BOD loading at
4,480 ppd whereas the 1990-1993 records identified only 4,088 ppd (Applying
the increased flow factor of 1 0757 from item 6 above, the BOD loading should
have been 4,819 ppd if BOD were directly tied to flow rate) The
Comprehensive Sewer Plan appears to have taken a very pessimistic approach
in identification of average annual BOD loadmg to the existing wastewater
treatment plant (ie increased influent strength over that actually observed)
8 The Comprehensive Sewer Plan identified the average winter BOD loading at
4,070 ppd whereas the 1990-1993 records identified an average of 4,201 ppd
(Applying the increased flow factor of 1 0757 from item 6 above, the winter
BOD loading should have been 4,378 ppd if BOD were directly tied to flow
rate) The Comprehensive Sewer Plan appears to have taken a slightly
pessimistic approach in identification of average winter BOD loading to the
existing wastewater treatment plant (ie influent strength slightly greater than
that observed)
9 The Comprehensive Sewer Plan identified the average annual TSS loading at
3,870 ppd whereas the 1990-1993 records identified an average of 4,034 ppd
(Applying the increased flow factor of 1 0757 from item 6 above, the TSS
loading should have been 4,163 ppd if TSS were directly tied to flow rate)
The Comprehensive Sewer Plan appears to have taken a slightly pessurustic
approach in identification of average annual TSS loading to the existing
wastewater treatment plant (ie influent strength slightly greater than that
observed)
10 The Comprehensive Sewer Plan identified the average winter TSS loading at
3,050 ppd whereas the 1990-1993 records identified an average of 3,663 ppd
(Applying the increased flow factor of 1 0757 from item 6 above, the winter
TSS loading should have been 3,281 ppd if TSS were directly tied to flow
rate) The Comprehensive Sewer Plan appears to have taken a very optimistic
approach in identification of average winter TSS loading to the existing
wastewater treatment plant (ie influent strength less than that observed)
TABLE 2
PASCO WWTP MONTHLY AVERAGE PERFORMANCE
1990-1993
MONTH
FLOW
(MGD)
BOO (mg/L)
IN OUT
TSS (mg/L)
IN OUT
BOO (lbsid)
IN OUT
TSS (lbsid)
IN OUT
% Removed
BOD TSS
Jan-90 2 029 275 34 182 21 4654 575 3080 355 88 88
Feb-90 2 06 276 52 200 22 4742 893 3436 378 81 89
_
Mar-90 2 121 224 53 194 25 3962 938 3432 442 76 87 -
Apr-90 2 262 164 24 202 18 3094 453 3811 340 85 91
May-90 2 319 176 24 183 17 3404 464 3539 329 86 91
Jun-90 2 411 229 23 171 17 4605 462 3438 342 90 90
Jul-90 2 543 215 26 183 13 4560 551 3881 276 88 93
Aug-90 2 685 197 21 204 14 4411 470 4568 314 89 93
Sep-90 2 577 163 21 212 19 3503 451 4556 408 87 91
Oct-90 2 377 188 23 202 19 3727 456 4004 377 88 91
Nov-90 2 196 162 19 209 18 2967 348 3828 330 88 91
Dec-90 2 273 153 41 210 37 2900 777 3981 701 73 82
Jan-91 2 284 214 37 196 25 4076 705 3734 476 83 87
Feb-91 2 218 222 37 205 27 4107 684 3792 499 83 87 _
Mar-91 2 247 230 31 201 24 4310 581 3767 450 87 88
Apr-91 2 258 212 31 212 24 3992 584 3992 452 85 89
May-91 237 185 31 213 17 3657 613 4210 336 83 92
Jun-91 2 458 149 27 202 24 3054 553 4141 492 82 88
Jul-91 2 575 188 32 191 20 4037 687 4102 430 83 90
Aug-91 2 771 156 52 220 20 3605 1202 5084 462 67 91
Sep-91 2 672 167 35 197 20 3722 780 4390 443 79 90
Oct-91 2 542 138 21 204 19 2926 445 4325 403 85 91
Nov-91 2 395 237 52 241 26 4734 1039 4814 519 78 89
Dec-91 2 254 196 30 173 25 3684 564 3252 470 85 86
Jan-92 2 238 183 28 183 24 3416 523 3416 448 85 87
Feb-92 2 291 199 27 180 25 3802 516 3439 478 86 86
Mar-92 2 287 152 30 178 21 2899 572 3395 401 80 88
Apr-92 2 459 225 31 260 21 4614 636 5332 431 86 92
May-92 2 516 172 26 193 23 3609 546 4050 483 85 88
Jun-92 2 694 139 19 191 17 3123 427 4291 382 86 91
Jul-92 2 862 157 26 191 19 3747 621 4555 455 83 90
Aug-92 2 852 164 20 208 19 3901 476 4947 452 88 91
Sep-92 2 703 179 30 188 19 4035 676 4238 428 83 90
Oct-92 2 669 188 34 169 18 4185 757 3762 401 82 _ 89
Nov-92 2 528 215 39 159 20 4533 822 3352 422 82 87
Dec-92 2 453 196 23 190 23 4010 471 3887 471 88 — 88
Jan-93 2 593 188 28 170 21 4066 606 3676 454 85 88
Feb-93 2 453 248 65 191 25 5074 , 1330 3907 511 74 87
Mar-93 2 451 243 60 172 32 4967 1226 3516 654 75 81
Apr-93 2 504 245 51 239 24 5116 1065 4991 501 79 90
May-93 2 606 234 64 213 20 5086 1391 4629 435 73 91
Jun-93 2 669 218 38 210 19 4853 846 4674 423 83 91
Jul-93 2 664 223 34 189 14 4955 755 4199 311 85 93
Aug-93 2 831 197 32 194 15 4651 756 4580 354 84 92
Sep-93 2 763, 204 35 199 16 4701 807 4586 369 83 92
Oct-93 2 651 237 31 170 16 5240 685 3759 354 87 91
Nov-93 2 612 218 28 174 17 4749 610 3790 370 87 90
Dec-93 2 499 215 37 169 20 44.81 771 3522 417 83 88
AVERAGE 2 474 199 34 196 21 4088 691 4034 426 83 89
PASCO2 XLS
Figure 1
PASCO WWTP AVERAGE MONTHLY FLOW
1990 - 1993
MGD
2 95
1990
OMMIIND
1991
-1992
-- 1993
1 95 —
175
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Figure 2
PASCO WWTP AVERAGE INFLUENT BOO
1990 - 1993
1990
— 1991
—1992
-1993
JAN
Figure 3
PASCO WWTP AVERAGE INFLUENT BOB
1990 - 1993
1990
— 1991
1992
—1993
lbs/day
Figin e 4
PASCO WWTP AVERAGE EFFLUENT BOB
1990 - 1993
mg/L
70 — Y... G1
1990
—1991
—1992
--- 1993
60 — AO. Alf
I
50 —
,
40 —
I .
mon
30
20
10
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Figure 5
PASCO WWTP AVERAGE EFFLUENT BOD
1990 - 1993
I bs Ida y
- - 1990
— 1991
— 1992
1993
Ftgure 6 1990
PASCO WWTP % REMOVAL: BOD 1991
1990 - 1993 1992
- 1993
% Removed
JAN FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT NOV DEC
Figure 7
PASCO WWTP AVERAGE INFLUENT TSS
1990 - 1993
mg/L
- 1990
....... —1991
1992
---- 1993
270
250
230
210
190
170 -
150
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Figure 8
PASCO WWTP AVERAGE INFLUENT TSS
1990 - 1993
lbs/day
5500
- 1990
1991
1992
-1993
APR MAY MAR
10
JAN FEB JUN JUL AUG SEP OCT NOV DEC
40
35
30
25
nn••••n• ••nnn•n,.,
kasvo ,asavoa ,,,..,ADIA11/414 araorte— Nam:* WOW* 20
nnn
15
Figure 9
PASCO WWTP AVERAGE EFFLUENT TSS
1990 - 1993
1990
— 1991
1992
— 1993
mg/L
••n••n
,(LF1.4
1990
1991
1992
1993
Figure 10
PASCO WWTP AVERAGE EFFLUENT TSS
1990 - 1993
lbs/day
Figure 11 1990
PASCO WWTP % REMOVAL : TSS - 1991
1990 - 1993 1992
-. 1993
% Removed
94
.... . •• '
, ,--
80
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
It is apparent that the Comprehensive Sewer Plan took a generally pessimistic approach to the
identification of BUD wastewater characteristics for the Pasco facility A pessimistic
approach is appropriate when looking at the design of a facility to meet an unsure future
condition, but has obviously led to the piggy-backing of conservative factors in the application
of effluent limits by WDOE which has resulted in an appeal of the NPDES permit
Table 3 identifies a less pessimistic estimate of the per capita BUD loading factors for the
City of Pasco wastewater treatment plant m comparison with those given in the
Comprehensive Sewer Plan (Comprehensive Sewer Plan figures given in parentheses)
TABLE 3
CITY OF PASCO
WASTEWATER TREATMENT PLANT
EXISTING PER CAPITA LOADING
Parameter _
Annual
Capita
Maximum
Month Capita
Maximum
Day
Capita
Maximum
Hour
Capita
Flow, gpcd 115 (113) 135 (130) 165 (147) 260 (249)
BUD, ppd _ 0 20 (0 22) 0 24 (0 32)
Winter BUD, ppd 0 20 (0 20) 0 24 (0 26)
- TSS, ppd 0 20 (0 19) 025 (023)
—Winter TSS, ppd 0 17 (0 15) 0 23 (0 20)
n
Utilizing these revised (not so conservative) per capita loading factors, revised projected flow
and loading conditions for the Pasco Wastewater Treatment can be calculated as shown in
Table 4 (Comprehensive Sewer Plan figures are given m parenthesis)
TABLE 4
CITY OF PASCO
WASTEWATER TREATMENT PLANT
PROJECTED POPULATION AND WASTEWATER LOADINGS
Criteria 1990' 2000 2005 2010 2018'
Population 20,340 28,200 33,500 39,800 55,770
Avg Annual Flow, MGD 234 (2 30) 3 24 (3 19) 3 85 (3 79) 4 58 (4 50) 6 41 (6 30)
Max Month Flow, MGD 275 (264) 3 81(3 66) 452 (435) 537 (5 17) 753 (724)
Max Daily Flow, MGD 336 (299) 465 (4 14) 5 53 (492) 657 (5 85) 920 (8 19)
Max Hour Flow, MGD 529 (5 06) 733 (701) 8 71 (8 33) 10 35 (9 89) 14 50 (13 86)
Avg Annual BOD, ppd 4068 (4480) 5640 (6200) 6700 (7370) 7960 (8760) 11,154 (12,170)
Max Month BOD, ppd 4882 (6500) 6768 (9000) 8040 (10,690) 9552 (12,700) 13,385 (17,790)
Winter Avg BOD, ppd 4068 (4070) 5640 (5640) 6700 (6700) 7960 (7960) 11,154 (11,150)
Winter Max Mo BOD, ppd 4882 (5300) 6768 (7330) 8040 (8710) 9552 (10,350) 13,385 (14,500)
Avg Annual TSS, ppd 4068 (3870) 5640 (5360) 6700 (6370) 7960 (7560) 11,154 (10,600)
Max Month TSS, ppd 5085 (5300) 7050 (7340) 8375 (8720) , 9950 (10,360) 13,943 (14,520)
Winter Avg TSS, ppd 3458 (3050) 4794 (4230) 5695 (5030) 6766 (5970) 9481 (8370) ,
Winter Max Mo TSS, ppd 4678 (3970) _ 6486 (5500) _ 7705 (6530) 9154 (7760) 12,827 (10,880)
I Figures in parenthesis for 1990 and 2018 come from the Facility Plan
By applying the less pessimistic per capita loading criteria, flow increases and BOD mass
loading decreases TSS mass loading is shown as increasing for the average annual condition,
but for the maximum month condition, TSS mass loading decreases It can be concluded that
the Comprehensive Sewer Plan design factors are generally overly conservative
REVISED NPDES PERMIT
Based on this evaluation of the City of Pasco's existing wastewater characteristics, we suggest
that the table included under CONDITION Si EFFLUENT LIMITATIONS of the NPDES
Permit be revised as follows for the year 2005 design condition
HDR ENGINEERING,
_ _
EFFLUENT LIMITATIONS a
Parameter Monthly Average Weekly Average
Biochemical Oxygen
Demand b (5-day) 30 mg/1 1130 lbs/day 45 mg/1 1695 lbs/day
Total Suspended Solids b 30 mg/1 1130 lbs/day 45 mg,/1 1695 lbs/day
Fecal Conform Bacteria 200/100 ml 400/100 ml
pH shall not be outside the range 6 0 to 9 0
Monthly Average Daily Maximum
Total Ammonia (as NH 3 -N) _ 83 mg,/1 190 mg/1
a The monthly and weekly averages are based on the arithmetic mean of the samples taken
with the exception of fecal conform, which is based on the geometric mean
b The monthly average effluent concentration for BOD 5 and Total Suspended Solids shall not
exceed 30 mg/1 or 85 percent removal of the respective monthly average influent
concentrations, whichever is more stringent
It appears that the matter of total pound limits for BUD and TSS is the last remaining issue in
the City's appeal of the NPDES permit Adjustment of the total pound limits to those as set
forth above would bring this entire matter to a conclusion Please give me a call and lets
discuss
Very Truly Yours,
Anthony H Krutsch
Vice President
cc Bob Alberts, City
Harold Posthuma, City
HDR file
DATE 12 /P 5 PJ4 LEGAL NO WO(
ACCOUNT NO 1.!•..( )55a
DESCRIPTION 2254 0RD1NANCr. NO
TIMES ( )01 INCHES ---1 .ci()
TUFA& 4,
tv0
- 1/k tv P 0 BOX 2608
PASCO WASHINGTON 99302 2608
PHONE (509) 582 1500
LLADVEL7YOZAM
INVOICE
SOLD TO
FASCO, CITY OF LEGALS
F.O. BOX 2 117
FASCO WA :;:):".oi
ICE This is an Invoice for legal advertising space Please pay from this invoice as no statement will be rendered
Please detach at perforation and return with payment
RIM
JAN 0 9 fiEU
DEPT
ORDINANCE 'NO 3070
AN ORDINANC,E concern-
ing the .carryinL out of a
system or plan for additions
and betterments to the ex-
tensions of the water works
utility of the City the modi-
fication of effluent flow
characteristics as identified
in the facility plan
amending the facility plan
and amending Ordinance
No 3040
WHEREAS on August 15
1994 the City Council ap-
proved Ordinance No
3040 an Ordinance relat-
ing to the water works util-
ity of the City specifying \
adopting and ordering the
carrying out of a system or
plan for additions and bet-
terments to the extensions
of the water works utility Of
the City authorizing the is-
suance of water and sewer
revenue bonds in the
amount of up to eight mil-
lion five hundred twenty
t housand dollars
($8 520 000 00) to obtain a
part of the funds with which
to pay the costs of carrying
out a portion of that system
or plan authorizing the is-
suance of a three million
dollar ($3 000 000 00) par
value Water and sewer rev
note pending the 4 NAN CE enue bond anticipation
of the bond fixing issuancethe date '
interest rates form matu-
rity terms covenants and
uses of the proceeds of
those bonds creating a
special note redemption
fund and a construction
fund - and providing for the
sale and delivery of the
note to West One Bank
Washington of Seattle
Washington and
WHEREAS in order to set-
tle an existing dispute with
the Washington State De-
partment of Ecology over
the conditions required in a
National Pollution Dis-
charge Elimination System
(NPDES) permit for the
City and its Wastewater
Treatment Facilities the
City has agreed to amend
he plan of additions and
betterments to and exten-
sions of the waterworks
utility of the City described 1
in Exhibit A to Ordinance
No 3040 which exhibit in
part provides for the modi-
fication of effluent flow
characteristics of the Cali s
Wastewater Treatment Fa-
cilities now therefore
THE CITY COUNCIL OF
THE CITY OF PASCO
WASHINGTON DO OR-
DAIN AS FOLLOWS
§1 That Ordinance No
3040 adopted by the City
Council on August 15
1994 is hereby amended
only to the extent that the
system or plan of additions
and betterments to and ex-
tensions of the waterworks
utility of the City described
in Exhibit A' attached
thereto and adopted by
Section 1 of said Ordi-
nance is hereby amended
by the exhibit attached
hereto titled CITY OF
PASCO WASTEWATER
FACILITIES PROJECT
DESIGN MEMORANDUM
NO 1 MODIFICATION OF
EFFLUENT CHARACTER-
ISTICS AS IDENTIFIED IN
THE FACILITY PLAN by
HDR Engineering Inc De-
cember 1994
§2 This Ordinance shall
take effect five (5) days
after passage and publica-
tion
Passed by the City council
of the City of Pasco at a
regular meeting this 19th
day of December 1994
City of Pasco
-s- Joyce DeFefice Mayor
Attest
-s- Cathenne D Seaman
Deputy City Clerk
Approved As T1 Form
s- Greg A Rtlostello
City Attorney
#2254 - 12/25/94
AYFODAVYY PallE3,15DH2f11010
COUNTY OF BENTON
ss
STATE OF WASHINGTON
ARLA AL FORD , being duly sworn,
deposes and says, I am the Legal Clerk of the Tr-City Herald, a
daily newspaper That said newspaper is a legal newspaper and
has been approved as a legal newspaper by order of the superior
court in the county in which it is published and it is now and has
been for more than six months prior to the date of the publication
hereinafter referred to, published countinually as a daily newspa-
per in Benton County, Washington That the attached is a true
copy of a 2254 ORDINANCE NO. :o7rt as it
was printed in the regular and entire issue of the Tr-City Herald
itself and not in a supplement thereof, time(s),
commencing on 101L.: , and ending on 12/ 25/ 9LI , and that said newspaper was regulary
distributed to its subscribers during all of this period
C.RALt 4atuit.4(
SUBSCRIBED AND SWORN BEFORE ME THIS
DAY OF j_a41J.i 11_44 ,
Notary public in and for the State of Wash-
ington, residing at F AEA CI WA
COMMISSION EXPIRES 7— AS-- ,A
MOTO
< TRANSACTION REPORT >
12-20-1994(TUE) 09 46
C -1- 1=2 A NI SI-1 I -1- 3
NO DA1E TIME DESTINATION STATION PG DURATION MODE RESULT
5474 12-20 09 37 15095821453 20 0°09 04 NORM E OK
20 0°09 04