Wastewater Treatment for Small Communities€¦ · Wastewater Treatment for Small Communities...

Environment EnvironnementCanada Canada

Wastewater Treatment for Small Wastewater Treatment for Small CommunitiesCommunities

Summary of the 2003 Workshop sponsored by Canadian Council of Ministers of the

Environment (CCME)


Presentation FormatPresentation Format

DefinitionsTechnology OptionsCost Comparison

Centralized vs. Decentralized Systems

Elements for Program Success


DefinitionsDefinitions• Small Community

• no clear cut• suggest 2000 people

• Type of Community• rural• cottage• fringe• semi-urban

• Treatment Systems• Centralized• De-centralized

- on-site- clusters

Centralized SystemCentralized System


Centralized System Cost

Population

Cos

t Per

Cap

ita

Collection = 70%

Treatment = 30%

OnOn--Site SystemSite System

Decentralized SystemDecentralized System

Population10,0002,000

Centralized Treatment

Lagoons / MechanicalDe-centralized Treatment

On-site / Clusters


Presentation FormatPresentation FormatDefinitions

≤ 2000 populationcentralized/decentralizedno clear cut solution

Technology OptionsCost Comparison

Centralized vs. Decentralized SystemElements for Program Success


Technology Options for Centralized Technology Options for Centralized SystemSystem

MechanicalLagoon


Activated Sludge PlantActivated Sludge Plant

RBC discs

drive

permeate

influent

aeration

Membrane AS plant Membrane AS plant (hollow fiber)(hollow fiber)

SBR process SBR process (Sequencing (Sequencing Batch Batch Reactor):Reactor):

------------------------Biol. processBiol. processand and sedimentationsedimentationin the samein the sametank:tank:

influent

filleffluent

excesssludge

cycle

aerationdecantation

sedimentation

Lagoon PerformanceLagoon PerformanceEffluent BODEffluent BOD

LAGOON FALL DISCHARGES

STORAGEMECHANICAL6 MONTHPLANTSSTORAGE

12 MONTH

0

10

20

30

BO

D m

g/L upper 95%

meanlower 95%

0S,1L 0S,1L AS EA4S,2L 4S,2L AL RBC(7 ,1 9) (1 5, 43 ) (5 ,7 ) (1 7, 39 ) (9 ,6 97 ) (2 5, 39 1) (1 0, 17 3) (1 0, 25 7)

AlkylphenolicsAlkylphenolics in STPsin STPs

0

100

200

300

400

500

600

700

800

900

A B C D E F G H I J K L M N O P G R S T U V W X Y Z A A A B

Site

Con

cent

ratio

n ( µ

g/L )

InfluentEffluent

G H J K L M

Median Per Cent Reduction of Acidic DrugsMedian Per Cent Reduction of Acidic DrugsThames River, Grand River and Highland Creek plantsThames River, Grand River and Highland Creek plants

-100

-75

-50

-25

0

25

50

75

100

Lagoon (4) Secondary (12) Tertiary (3)

Treatment Type

% Re

ducti

on

IbuprofenGemfibrozilNaproxenTriclosanKetoprofenDiclofenacIndomethacin


Technology Options for Technology Options for Decentralized SystemDecentralized System

soil-basedpackage plants

19th Century19th CenturyEnglandEngland

SoilSoil--based Systembased System

Examples of Dispersal Technologies

Drip IrrigationDrip Irrigation Chamber SystemChamber System

Mound SystemMound SystemContour TrenchContour Trench

Peat Filter + WetlandPeat Filter + Wetland

Sand Filter

Splitter Box

Effluent

InfluentDosing TankSeptic Tank

Recirculating Sand Filter Schematic

Waterloo Waterloo BiofilterBiofilter

AirAir--tight 5000 L/d Polyethylene Tankstight 5000 L/d Polyethylene Tanks

modules installed as needednew or existing garage-type structurestandard plumbing & electricalno confined space problem

Waterloo 30Waterloo 30--40 m40 m33/d ISO Container/d ISO Container

30-40 m3/d ISO container combines building & Biofiltershipped as standard container; ideal for off-shoreSt. Louis & Paddockwood, Saskatchewan


Presentation FormatPresentation FormatDefinitionsTechnology Options

centralized/decentralized systemsno clear cut

Cost ComparisonCentralized vs. Decentralized System

Elements for Program Success

Scenario 1 Scenario 1 –– Rural CommunityRural Community

450 people135 homes1 acre lots50% on-site systems failed

Scenario 1 Scenario 1 –– Centralized SystemCentralized System

collectiongravity sewers

treatmentfacultative lagoondisinfection

Scenario 1 Scenario 1 –– Cluster SystemCluster System

collectionsmall diameter gravity sewers

treatmentseptic tanksand filterleach field

Scenario 1 Scenario 1 –– OnOn--Site SystemSite System

failing on-site systemsseptic tank and leach field

new on-site systemsseptic tanksand filterleach field


Summary of Rural Community System Summary of Rural Community System Costs (1995 $)Costs (1995 $)

System Option Capital Cost Annual O & M Cost

Total Annual Cost

Centralized System $ 2,321,840 $ 29,740 $ 216, 850

Small Cluster System $ 598,100 $ 7,290 $ 55,500

On-site System $ 510,000 $ 13,400 $ 54,500

Rural community consists of 450 people in 135 homes


Scenario 2 Scenario 2 –– Fringe CommunityFringe Community

770 people → 1550 people

220 homes → 443 homes

½ acre lots50% (110 homes) failed on-site systems


Summary of Fringe Community System Summary of Fringe Community System Costs (1995 $)Costs (1995 $)

System Option Capital Cost

Annual O & M Cost

Total Annual Cost

Centralized Systemsat 5 miles from existing sewerat 1 mile from existing sewer

$ 5,377,800$ 3,322,900

$ 95,900$ 83,800

$ 529,300$ 351,600

Small Cluster Systems $ 3,783,700 $ 18,000 $ 322,900

On-site Systems $ 2,117,100 $ 59,240 $ 229,900

Fringe community consists of 1,550 people in 43 homes(includes future growth)


ConclusionConclusion

A decentralized system is generally costeffective for:

rural communityfringe community(except when situated very close to an existing centralized system)

Each case based on site-specific considerations


Presentation FormatPresentation Format

DefinitionsTechnology OptionsCentralized vs. Decentralized Cost Comparison

decentralized system could be cost effectiveElements for Program Success


Elements for Program SuccessElements for Program Success

appropriate technologyresponsive regulationadequate financetighter management


Appropriate TechnologyAppropriate Technology

technology certification/verificationinnovative technology demonstrationeducation and training


Responsive Regulatory ControlResponsive Regulatory Control

harmonize regulation coverageperformance-based limits (vs. prescriptive codes)inspection and monitoringenforcementlicensed/certified practitioners


Adequate FinancingAdequate Financing

government grantsequitable distribution

revolving fundsamalgamation to district organizationpublic-private partnership


EPA Proposed Five Levels of System EPA Proposed Five Levels of System ManagementManagement

1. homeowner awareness2. maintenance contracts3. operating permits4. RME operation and maintenance5. RME ownership/management

* RME = Responsible Management Entity

Application of the Application of the Management LevelsManagement Levels

Envi

ron

me n

tal S

ens i

tivi

tyEn

viro

nm

e nta

l Sen

s iti

vity

Pu

b lic

Hea

lth

Pu

b lic

Hea

lth

Was

t ew

ater

Ch

arac

ter i

s tic

sW

ast e

wat

er C

har

acte

r is t

ics

Trea

tmen

t C

ompl

exit

yTr

eatm

ent

Com

plex

ity

Incr

easi

ng

Ri s

ksIn

crea

sin

g R

i sks

2

Risk FactorsRisk Factors

1

3

4

5

Inventory & maintenanceInventory & maintenanceawarenessawareness

Maintenance contractsMaintenance contracts

Operating permitsOperating permits

RME O&MRME O&M

RME ownershipRME ownership

MANAGEMENT LEVEL 1MANAGEMENT LEVEL 1Homeowner Awareness of Maintenance NeedsHomeowner Awareness of Maintenance Needs

Covers conventional septic systemsLow environmental sensitivity

i.e., adequate space, separation distance, etc.

Local agency is aware of system locationsPeriodic operation and maintenance reminders

MANAGEMENT LEVEL 2MANAGEMENT LEVEL 2Maintenance ContractsMaintenance Contracts

Complex systems given more attention

e.g., mounds, pressure dosed systems

Maintenance contracts with trained service providers

MANAGEMENT LEVEL 3MANAGEMENT LEVEL 3Operating PermitsOperating Permits

Minimum for clusters, aerobic units, large capacity systems

Sensitive siteslakes, aquifers

Renewable operating permitsPerformance requirementsRegular monitoring and reporting

MANAGEMENT LEVEL 4MANAGEMENT LEVEL 4Responsible Management EntityResponsible Management Entity

Operation and MaintenanceOperation and MaintenanceVery sensitive areas - recreational uses, wellhead protection

Responsible Management Entity for operation and maintenance

Systems still owned by homeownersRME performs routine inspections & maintenanceensures consistent performance

MANAGEMENT LEVEL 5MANAGEMENT LEVEL 5Responsible Management Entity Responsible Management Entity

Ownership and ManagementOwnership and Management

Ultra sensitive environment and public health protection

Same as Level 4, except RME is owner

Professional management of all activities

Analogous to centralized collection and treatment


Canadian Case Study Canadian Case Study –– Nova ScotiaNova Scotia

Guysborough (population 360)formed a wastewater management district

one cluster – small conventional treatment plantone cluster – aerated lagoonindividual homes – septic tank and leaching bed

all home owners paid $ 2,100 initially and have annual fees of $ 125 (in 1994)


Canadian Case Study Canadian Case Study –– Nova ScotiaNova Scotia19 communities in Nova Scotia were considered 17 were recommended decentralized system

3 formed Wastewater Management District (WMD)6 chose to centralize5 actively considering WMD5 in prolonged debate

Problemsequity costs and servicespublic perception favours centralized system


Presentation FormatPresentation FormatDefinitionsTechnology OptionsCost Comparison

Centralized vs. Decentralized SystemElements for Program Success

technologyresponsive regulationadequate financetighter management


Examples of Provincial InitiativesExamples of Provincial Initiatives

Nova Scotia – wastewater management district– centre for water resource studies– program review

Newfoundland – technology demonstration

Quebec – updated regulation• system maintenance• technology performance standards• new technology testing & certification


Examples of Provincial InitiativesExamples of Provincial Initiatives

Ontario – municipal agreement for privatesystems

– require septage treatment– Ontario rural wastewater centre

British Columbia – new regulation for on-site systems

• performance-based standards• O&M requirements• training and certification• enforcement


Future CoordinationFuture Coordinationnational body to coordinate efforts

harmonize provincial regulationsprioritize researchprotocols for technology testing/certification/selectionnational best practicefinancingcontinue dialogue among stakeholders


AcknowledgementAcknowledgementSome slides in this presentation were prepared with input from the following participants at the 2003 CCME workshop

Robert Bastian – U.S. EPAOtto Nowak – Vienna University of TechnologyKathleen Blanchard – Intervale AssociatesDaniel Smith – University of AlbertaDick Otis – Ayres AssociationJames Owen – MSA Professional ServicesCraig Jowett – Waterloo Biofilter Systems Inc.

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