CENTRALIZED CENTRALIZED vsvs

DECENTRALIZED DECENTRALIZED

WASTEWATER WASTEWATER

MANAGEMENT FOR CAPE MANAGEMENT FOR CAPE

CODCOD

Jim Jim KreisslKreissl

USEPA ORD, retiredUSEPA ORD, retired

TYPICAL CHARACTERISTICSTYPICAL CHARACTERISTICS�� CENTRALIZEDCENTRALIZED

–– Conventional gravity sewers (deeply placed Conventional gravity sewers (deeply placed

with manholes & lift stations)with manholes & lift stations)

–– One treatment facility (normally activated One treatment facility (normally activated

sludge variation)sludge variation)

–– Effluent discharge directly to surface waterEffluent discharge directly to surface water

�� DECENTRALIZEDDECENTRALIZED

–– Onsite or cluster systemsOnsite or cluster systems

–– Multiple treatment and soil dispersal or reuse Multiple treatment and soil dispersal or reuse

facilitiesfacilities

–– LowLow--cost, shallow sewer systems for clusterscost, shallow sewer systems for clusters

GENERAL COMPARISONSGENERAL COMPARISONS

�� CENTRALIZEDCENTRALIZED�� Old and taught in Old and taught in engineering schoolsengineering schools

�� High capital costHigh capital cost

�� Transfers water away Transfers water away from source basinfrom source basin

�� Long, disruptive Long, disruptive constructionconstruction

�� Highly trained operator Highly trained operator neededneeded

�� Potential for catastrophic Potential for catastrophic failurefailure

�� DECENTRALIZEDDECENTRALIZED

�� New and not taught New and not taught in engineering schoolsin engineering schools

�� Lower capital costsLower capital costs

�� Keeps water closeKeeps water close

�� Short, lessShort, less--disruptive disruptive constructionconstruction

�� Basic operation skills Basic operation skills requiredrequired

�� Failure consequences Failure consequences felt in smaller areafelt in smaller area

VISUAL COMPARISONVISUAL COMPARISON

Centralized wastewater treatment Decentralized approach

WHY IS DECENTRALIZED WHY IS DECENTRALIZED

VALUABLE?VALUABLE?�� Existing CommunitiesExisting Communities

�� Minimal investment and maximum flexibility to solve Minimal investment and maximum flexibility to solve wastewater and other waterwastewater and other water--related problems.related problems.

�� Water stays in original watershed Water stays in original watershed

�� Minimal disruption to communityMinimal disruption to community

�� DevelopersDevelopers

�� Allows more lots and greater open space.Allows more lots and greater open space.

�� Open and common areas can serve as soil Open and common areas can serve as soil dispersal and/or reuse facility locations and dispersal and/or reuse facility locations and social amenities.social amenities.

�� Increased developer profits and resident Increased developer profits and resident aesthetics.aesthetics.

WHY IS IT BEING IGNORED ON WHY IS IT BEING IGNORED ON

THE CAPE?THE CAPE?

““Too expensive to buildToo expensive to build””

““Too many systems to operateToo many systems to operate’’

““Too much land needed for satellite systemsToo much land needed for satellite systems””

““Cannot meet Cannot meet TMDLTMDL’’ss 100% nitrogen reduction 100% nitrogen reduction

like sewerslike sewers””

““Cannot put soil dispersal under roadsCannot put soil dispersal under roads””

““Not enough data on smallNot enough data on small--diameter sewersdiameter sewers””

““Users and developers dislike these systemsUsers and developers dislike these systems””

WHAT IS A CONVENTIONAL WHAT IS A CONVENTIONAL

SOLUTION?SOLUTION?

Collection System Collection System –– Deep (8 to 25 feet) pipes, Deep (8 to 25 feet) pipes, with frequent manholes, and lift stations as with frequent manholes, and lift stations as needed to maintain gravity flow at minimum needed to maintain gravity flow at minimum velocityvelocity

Treatment System Treatment System –– A single large treatment A single large treatment facility, usually some form of activated sludge, facility, usually some form of activated sludge, with additional processes as necessarywith additional processes as necessary

Discharge Discharge -- Usually, surface water discharge, Usually, surface water discharge, extracting waters from several upstream extracting waters from several upstream basins to one downstream location; however, basins to one downstream location; however, on the Cape discharge must be to soilon the Cape discharge must be to soil

CONVENTIONAL GRAVITY SEWERSCONVENTIONAL GRAVITY SEWERS

CONVENTIONAL SEWERCONVENTIONAL SEWER

�� Above orAbove or

Below WaterBelow Water

Table (WT)Table (WT)

�� When sewer is When sewer is

below WT, nitrobelow WT, nitro--

gen contaminatesgen contaminates

ground waterground water

CONVENTIONAL SEWER CONVENTIONAL SEWER

COLLECTIONCOLLECTION�� COST ~83% of COST ~83% of

$52,000/edu + hookup $52,000/edu + hookup

fee (Chatham)fee (Chatham)

�� Construction will cause Construction will cause

major town disruption for major town disruption for

long periodlong period

�� Potentially could lower Potentially could lower

water table & increase water table & increase

salt water intrusionsalt water intrusion

�� O/M $3,100/edu/yr O/M $3,100/edu/yr

(Chatham)(Chatham)

Effluent Sewers (STEG and STEP)

LOWLOW--COST COLLECTION SYSTEMSCOST COLLECTION SYSTEMS

Effluent Sewer

(STEG)

Composed of:

�interceptor tanks (with

pumps for STEP)

�building sewers and service

lines

�small diameter

collection mains

Cost <$10,000/edu

O/M $230-260/edu/yr

Vacuum System is

composed of:

�holding tanks with

vacuum valves

�collection mains

�a central vacuum

collection station

COST $10-15,000/edu

O/M $130-160/edu/yr

LOWLOW--COST COLLECTION SYSTEMSCOST COLLECTION SYSTEMS

Vacuum System

Vacuum Sewers

LOWLOW--COST COLLECTION SYSTEMSCOST COLLECTION SYSTEMS

Composed of:

�small-diameter

pressurized

collection system

�Grinder/pump with

controls

COST $9,500

O/M $280/edu/yr

Grinder Pump

To TreatmentGrinder Pump System

Grinder Pump System

LOWLOW--COST COLLECTION SYSTEMSCOST COLLECTION SYSTEMS

�� Over a thousand alternative collection systems Over a thousand alternative collection systems (ACS) exist, and always have significantly lower (ACS) exist, and always have significantly lower capital costs than conventional (~50%)capital costs than conventional (~50%)

�� ACS reduces infiltration and inflow (I/I) owing to ACS reduces infiltration and inflow (I/I) owing to shallow placement in the soil profile (2.5 ft shallow placement in the soil profile (2.5 ft vsvs up up to 25 ft), fewer and tighter joints, and absence to 25 ft), fewer and tighter joints, and absence of manholes and few if any lift stationsof manholes and few if any lift stations

�� Require less community disruption (not under Require less community disruption (not under roads), shorter construction duration (shallow), roads), shorter construction duration (shallow), and much lower O/M personnel demand than a and much lower O/M personnel demand than a conventional system with multiple lift stationsconventional system with multiple lift stations

CONVENTIONAL TREATMENT = CONVENTIONAL TREATMENT =

ACTIVATED SLUDGE PROCESSACTIVATED SLUDGE PROCESS

CENTRALIZED TREATMENT MAY CENTRALIZED TREATMENT MAY

NOT BE THE BEST CHOICENOT BE THE BEST CHOICE

�� Activated sludge was developed to reduce size Activated sludge was developed to reduce size of treatment facilities in large cities (NY, of treatment facilities in large cities (NY, BOSTON) by intensifying biological action with BOSTON) by intensifying biological action with skilled operators and added energy and airskilled operators and added energy and air

�� Activated sludge is the highest energy user, Activated sludge is the highest energy user, most sensitive to upset, and the most operatormost sensitive to upset, and the most operator--intensive treatment system used todayintensive treatment system used today

�� More modern activated sludge systems More modern activated sludge systems incorporate membranes in place of large incorporate membranes in place of large clarifiers, but are best suited to larger flows clarifiers, but are best suited to larger flows

WHAT KINDS OF TECHNOLOGY ARE WHAT KINDS OF TECHNOLOGY ARE

TYPICALLY EMPLOYED IN CLUSTER TYPICALLY EMPLOYED IN CLUSTER

TREATMENT SYSTEMS?TREATMENT SYSTEMS?

More passive treatment systems that can better More passive treatment systems that can better withstand influent variability than activated sludge, withstand influent variability than activated sludge, require lower energy & are more simply operatedrequire lower energy & are more simply operated

More reliable systems that require a minimum of O/M More reliable systems that require a minimum of O/M because of fewer electrobecause of fewer electro--mechanical components and mechanical components and process process judgementjudgement requirements, requirements, egeg, once per week , once per week visits instead of daily onesvisits instead of daily ones

Systems that can meet effluent requirements as well as Systems that can meet effluent requirements as well as conventional approaches, but require only a few O/M conventional approaches, but require only a few O/M visits per week versus 24/7 operationvisits per week versus 24/7 operation

SINGLESINGLE--PASS MEDIA FILTERSPASS MEDIA FILTERS

Inspection RiserService

Manhole

Outlet

Pipe

Inlet

Watertight

Tank

�Aerobic, fixed-film treatment system that treats septic tank effluent by filtering it through relatively fine sand or other media.�Typically removes 25 to 50% of total nitrogen

RECIRCULATING MEDIA FILTERRECIRCULATING MEDIA FILTER

CONSTRUCTED WETLANDSCONSTRUCTED WETLANDS

Subsurface

constructed

wetlands are most

commonly used for

small clusters with

lots of land

Wastewater flows

horizontally below

the media surface.

Nitrogen removal is

minimal(<20%)and

no DO is the norm. Clay Township Regional Water District, Indiana

DENITRIFICATION IS USED FOR DENITRIFICATION IS USED FOR

ALL TREATMENT SYSTEMSALL TREATMENT SYSTEMS

COMPARISON OF CENTRALIZED COMPARISON OF CENTRALIZED vsvs

DECENTRALIZED DENITRIFICATIONDECENTRALIZED DENITRIFICATION

�� Essentially they are the sameEssentially they are the same

�� Smaller systems can supply their own labile Smaller systems can supply their own labile carbon or use a different pathway so they will carbon or use a different pathway so they will not need an external source of carbonnot need an external source of carbon

�� This builtThis built--in carbon reduces O/M requirements, in carbon reduces O/M requirements, improves safety & causes less neighborhood improves safety & causes less neighborhood disturbance disturbance

�� Both the centralized and proposed decentralized Both the centralized and proposed decentralized treatment approaches should meet 3treatment approaches should meet 3--5 mg/L of 5 mg/L of total nitrogen in their effluentstotal nitrogen in their effluents

DISPERSAL/DISCHARGEDISPERSAL/DISCHARGE

CHATHAMCHATHAM’’S DENITRIFIED EFFLUENT S DENITRIFIED EFFLUENT

TREATMENT & DISPERSALTREATMENT & DISPERSAL

�� The Chatham plan jams effluent into soil at >4 The Chatham plan jams effluent into soil at >4 times the highest acceptable loading for times the highest acceptable loading for attaining significant treatment in the soil.attaining significant treatment in the soil.

�� The Chatham facility effluent will likely remain The Chatham facility effluent will likely remain high in nitrogen all the way to the high in nitrogen all the way to the sulphursulphursprings subsprings sub--embayment and will increase the embayment and will increase the nitrogen loading to 66 kg/day or 9 times the nitrogen loading to 66 kg/day or 9 times the present loading from that areapresent loading from that area

�� Based on the Cape USGS data, viruses that will Based on the Cape USGS data, viruses that will remain in the remain in the undisinfectedundisinfected Chatham effluent Chatham effluent will travel 1.7 miles will travel 1.7 miles downgradientdowngradient from the from the treatment plant to the receiving baytreatment plant to the receiving bay

DECENTRALIZED EFFLUENT DECENTRALIZED EFFLUENT

TREATMENT & DISPERSALTREATMENT & DISPERSAL

�� With some variation depending on the location With some variation depending on the location

and number of decentralized facilities, effluent and number of decentralized facilities, effluent

will be spread over most of the original basins, will be spread over most of the original basins,

reducing water quantity impacts on the ponds reducing water quantity impacts on the ponds

and and embaymentsembayments

�� The soil dispersal application rates assure that The soil dispersal application rates assure that

soil treatment will occur, in the case of nitrogen, soil treatment will occur, in the case of nitrogen,

an additional 40%+ could be removed by drip an additional 40%+ could be removed by drip

dispersal application to the soildispersal application to the soil

DECENTRALIZED TREATMENT/DISPERSAL DECENTRALIZED TREATMENT/DISPERSAL

SYSTEM REJECTION FOR LACK OF LANDSYSTEM REJECTION FOR LACK OF LAND

�� Decentralized systems are largely underground Decentralized systems are largely underground and allow public use of surface for recreationand allow public use of surface for recreation

�� Parts of the decentralized treatment systems Parts of the decentralized treatment systems that must be accessed can, like centralized lift that must be accessed can, like centralized lift stations, be aesthetically improved with stations, be aesthetically improved with vegetation and architectural treatmentvegetation and architectural treatment

�� The Chatham dismissal for inadequate land was The Chatham dismissal for inadequate land was belied by (1) the search for land to discharge belied by (1) the search for land to discharge the plant influent, which turned up dozens of the plant influent, which turned up dozens of sites in 13 subsites in 13 sub--embayment basins, and (2) embayment basins, and (2) unrealistically high land requirements.unrealistically high land requirements.

WHERE ARE THESE APPROACHES WHERE ARE THESE APPROACHES

BEING USED?BEING USED?

�� There are hundreds of such distributed There are hundreds of such distributed management and decentralized technology management and decentralized technology solutions employing decentralized technologies solutions employing decentralized technologies across the US, many of which are being studied.across the US, many of which are being studied.

�� The following list includes numerous sites where The following list includes numerous sites where successful decentralized systems are in successful decentralized systems are in operation. The causes for their adoption vary operation. The causes for their adoption vary and their final designs are quite differentand their final designs are quite different

�� The listed locations provided are only examples, The listed locations provided are only examples, and many more exist than these.and many more exist than these.

DECENTRALIZED SYSTEMS WITH DECENTRALIZED SYSTEMS WITH

SIMILAR PROBLEMSSIMILAR PROBLEMS�� Block Island, Rhode Block Island, Rhode IslandIsland

�� La Pine, OregonLa Pine, Oregon

�� Willard, New MexicoWillard, New Mexico

�� 2 dozen New Jersey 2 dozen New Jersey developments served by developments served by American WaterAmerican Water

�� Otter Tail Lake, Otter Tail Lake, MinnesotaMinnesota

�� Georgetown Divide PUD, Georgetown Divide PUD, CaliforniaCalifornia

�� Stinson Beach, CaliforniaStinson Beach, California

�� Mobile County, AlabamaMobile County, Alabama

�� Loudoun County, VALoudoun County, VA

�� Bethel Heights, ArkansasBethel Heights, Arkansas

�� Pima County, ArizonaPima County, Arizona

�� Santa Fe, New MexicoSanta Fe, New Mexico

�� Cave Springs, ArkansasCave Springs, Arkansas

�� LubeckLubeck, Germany, Germany

�� WickfordWickford Village, RIVillage, RI

�� BeecroftBeecroft, NSW, Australia, NSW, Australia

ALL THESE LOCATIONS HAVE ALL THESE LOCATIONS HAVE

CENTRALIZED MANAGEMENT CENTRALIZED MANAGEMENT

PROGRAMS THAT HAVEPROGRAMS THAT HAVE……Public education and involvement through

planning, implementation and operation phases

Dynamic inventory and billing databases that are updated whenever any service is provided

Requirements to use only trained and certified/licensed service providers

All necessary powers to set/enforce rules and collect necessary fees to remain sustainable

MOST SUCCESSFUL CASE STUDIES ARE CHARACTERIZED BY…

MOST SUCCESSFUL CASE STUDIES ARE MOST SUCCESSFUL CASE STUDIES ARE

CHARACTERIZED BYCHARACTERIZED BY……

Adoption of decentralized approaches after Adoption of decentralized approaches after

rejecting cost estimates of conventional systemsrejecting cost estimates of conventional systems

Adoption of only the strongest community involvement Adoption of only the strongest community involvement processes during the selection, design, construction, and processes during the selection, design, construction, and operational phases of the project, as well as in rule operational phases of the project, as well as in rule developmentdevelopment

The most effective programsThe most effective programs……

Require signed Require signed easementseasements for access by RMEfor access by RME

Include regular Include regular inspectionsinspections of all key componentsof all key components

Include the Include the power to enforcepower to enforce needed repairs through needed repairs through liens, tax bill addliens, tax bill add--ons, or water/wastewaterons, or water/wastewater shutoffshutoff

THANKS FOR YOUR THANKS FOR YOUR

ATTENTIONATTENTION

Any Questions?Any Questions?