Ottawa River Ottawa River Public Meeting #2 –Public Meeting #2 –

OptionsOptionsLong Term Combined Sewer Overflow Control Plan Input

March 2, 2005

Discussion AgendaDiscussion Agenda

• Long Term Control Plan Recap

• Control Alternatives• Common Elements• Alternative Differentials

• Alternative Descriptions

• Opportunity for Input

CSO Control PlanningCSO Control Planning

• The City must control CSO discharges according to the consent decree

• Alternatives are being evaluated with respect to their feasibility, associated benefits and costs

• Public input on alternatives considered is sought in tonight’s meeting

Project TimelineProject Timeline

• The Long Term Control Plan Document is scheduled to be submitted to USEPA in July 2005

• A review and modification period will follow the plan submittal

• The work identified in the plan is to be completed by August 31, 2015

Ottawa River Ottawa River Combined AreaCombined Area

Ottawa River Ottawa River Overflow FrequencyOverflow Frequency

Outfall Annual Frequency

61 12

62 25

63 2

64 21

65 14

67 13

Ottawa River Ottawa River Overflow VolumeOverflow Volume

Outfall Annual Volume (MG)

61 3

62 52

63 <1

64 40

65 5

67 6

Total 107

Alternative EvaluationAlternative Evaluation

• Alternative evaluation is based on reducing the frequency of overflow to 0 – 12 times a year

• Total elimination of overflows would only occur in the most costly alternatives

CSO Control OptionsCSO Control Options

• Three basic control options were considered:• Storage – holds excess flow until capacity is

available• Treatment – cleans flow before it is discharged;

disinfects and removes pollutants• Separation – provides new sanitary or storm sewers

so that combined sewers are eliminated

• Flow reduction / rerouting can enhance the above options

Measurable Benefits of Measurable Benefits of CSO ControlCSO Control

• Reduced frequency of CSO discharge

• Reduced volume of discharge

• Reduction in pollutants discharged

• Better water quality in rivers

Alternative DefinitionAlternative Definition

• General alternatives have been identified for the Ottawa River Area

• The following are common aspects of the defined alternatives

Alternative Common Alternative Common ElementsElements• The number of overflow locations would be reduced

from the existing 6 to 2

Alternative Common Alternative Common ElementsElements

• Remaining overflow would have less pollutant concentration

Oxygen Demand (CBOD)

0

20

40

60

80

100

120

Before Low Control High Control Separation

co

nc

en

tra

tio

n (

mg

/l)

Bacteria (Fecal Coliform)

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

Before Low Control High Control Separation

co

nc

en

tra

tio

n (

cfu

/10

0m

l)

Alternative Common Alternative Common ElementsElements

• 1 of the overflow locations would be relatively rare (occurring approximately once a year)

Alternative Common Alternative Common ElementsElements

• The frequency of overflow from the primary discharge location would be reduced

CSO Frequency

0

5

10

15

20

25

30

Current Future Max Future Min

#/ y

ea

r

Alternative Common Alternative Common ElementsElements

• The total volume of untreated combined sewer overflow would be reduced

CSO Untreated Overflow Volume

0

20

40

60

80

100

120

Current Future Max Future Min

MG

/ ye

ar

Alternative Common Alternative Common ElementsElements

• Some partially separated areas would be completely separated

Alternative Common Alternative Common ElementsElements

• A number of outfalls would be consolidated

Ottawa River Ottawa River Overall AlternativeOverall Alternative

Alternative OptionsAlternative Options

• There are several different options that must be considered prior to determining the final alternatives

• These options include: • Location of facilities• Use of treatment technology• Degree of control• Cost

• Siting location – several potential sites have been identified

Alternative OptionsAlternative Options

Alternative OptionsAlternative Options

• Treatment technology• The level of treatment technology may vary

Treatment Type

050

100150200250300350400

Storage Disinfection PrimaryTreatment +Disinfection

AdvancedTreatment

Co

mp

lex

ity

an

d C

os

t;

Eff

lue

nt

Qu

alit

y

Alternative Options – Alternative Options – Level of ControlLevel of Control

• Total frequency of untreated discharge vs. cost of various alternatives

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

Re

lati

ve

Co

st

0 Overflows / Year

1-3 Overflows / Year

4-7 Overflows / Year

8-12 Overflows / year

Selection of AlternativeSelection of Alternative• Siting Options

• Windemere Blvd. – would abandon existing street and use for storage or treatment

• Advantage: lowest cost, low public disruption.

• Disadvantage: small site – limits level of control

• Joe E. Brown Park – would use portion of park for facility siting

• Advantage: large open area

• Disadvantage: impacts on public use

• Old Jeep Plant parking area

• Advantage: industrial area – minimal public impact

• Disadvantage: not city-owned property, high cost for sewers

Selection of AlternativeSelection of Alternative

• Technology Selection• Storage is high cost to build, but easiest to operate;

largest use of site • Higher level treatment technology would produce

better quality effluent, but would be more complex to operate; overall lower cost than storage; treated discharges would occur from these facilities

• Separation can accomplish control of CSO discharges; in some locations it can be cost-competitive with other options

Selection of AlternativeSelection of Alternative

• Level of Control Selection• The range of level of control is between 0 – 12

overflows per year• Most approved plans have overflow frequencies of 2

– 6 per year • Water quality benefits are limited if frequency is

reduced to 8 per year or less• Costs increase exponentially as level of control goes

to zero

Selection of AlternativeSelection of Alternative

• Cost• The range of cost is large • Every decision on level and type of control has a

cost implication• There tend to be diminishing returns for larger

facilities

How you can helpHow you can help

• Provide input on the following alternative elements:• Site Selection• Technology Preferences• Frequency of Overflow • Cost

• Provide other comments and ask questions