Littleton, MA –Smart Sewering Strategy: Affordable Green ... Knowles... · Operations Repair &...

Littleton, MA Littleton, MA –– Smart Sewering Strategy:Smart Sewering Strategy:

Affordable Green Sewering, FitAffordable Green Sewering, Fit--ForFor--PurposePurpose

Paul KnowlesPaul Knowles

Green First:

December 8, 2011 Falmouth MA

Introduction

• Intro to Littleton challenge and principles of

smart sewering

• The six steps of smart sewering analysis

• Opportunities for green decentralized

solutions for the cape, provided by a

Responsible Management Entity

Motivation for sewer in Littleton

• Affordable at

small-scale

• Concentrate

growth in the

commercial

center

• Consider social

and ecological

benefits

Anticipated Wastewater Flows – 20 year build-out

Use Flow (gpd) Yr. 0 Yr. 5 Yr. 10 Yr. 15 Yr. 20

Park & Co. Retail 10,000 - 7,000 3,000 - -

Restaurant 28,000 - 19,600 8,400 - -

Hotel 11,000 - 7,700 3,300 - -

Medical

Office

4,800 - 3,360 1,440 - -

VCB Retail 7,500 1,000 - 3,275 - 3,225

Restaurant 20,000 500 - 10,900 - 8,600

Residential 38,500 11,000 - 10,945 - 16,555

Office 20,000 11,000 - 400 - 8,600

VOD Industrial 14,400 - - 7,200 3,312 3,888

Office

Commercial

7,500 - - 3,750 1,725 2,025

Wells/IBM Office

Commercial

47,000 25,000 12,500 4,500 - 5,000

KIMBALL* Commercial 15,000 15,000 - - - -

TOTAL 63,500 50,160 57,110 5,037 47,893

CUMULATIVE 63,500 113,660 170,770 175,807 223,700

Smart Sewering Case Study: Littleton, MA

Q) How do we keep a 185,000 gpd system affordable

without requiring a larger sewer disctrict?

A) Perform a Smart Sewering Study which considers:

1. Community values

2. Environmental issues

3. Minimizing risk to tax base

4. Appropriate technology

5. Improving affordability for users

6. Economic Feasibility Analysis

Community Values

20 Parameters: Environmental, Economic and Social

Community Values

232 responses: top 4 parameters by score

Environmental Issues

3 town wells in Merrimack River Watershed

CONCORD

RIVER

WATERSHED

MERRIMACK

RIVER

WATERSHED

I-495

STUDY

AREA


• Water distribution in Littleton

• Recharges are on-lot septic system

• Net transfer of water from Merrimack to Concord

The Massachusetts Executive Office of Environmental Affairs (EOEA) and the Charles River Watershed

Association/ESS Group (2007), Community Water Budget Report, Town of Littleton

CONCORD

RIVER

WATERSHE

D

MERRIMACK

RIVER

WATERSHED


APRIL (HIGH FLOW) SEPTEMBER (LOW FLOW)

Sub-basin

NameArea (Mi²)

Natural

Stream Flow

(MGD)

Human Total

Vol Impact

(MGD)

Human

Relative

Impact

(%)

Natural

Stream

Flow

(MGD)

Human

Total Vol

Impact

(MGD)

Human

Relative

Impact

(%)

Bennet's 7.1 14.67 -2.32 -15.83 2.25 -1.5 -66.57

Beaver 13.1 27.49 -0.9 -3.28 4.27 -1.15 -26.87

Gilson 3.4 6.73 -0.19 -2.77 0.11 0 2.33

Vine 9.9 19.62 -0.37 -1.9 2.95 0.09 2.93

Fort Pond 7.2 14.27 -0.08 -0.58 1.3 0.05 3.72

Nagog Pond 0.6 1.16 0 0.18 1.05 0.05 4.87

Resulting change in natural stream flow during high

and low seasonal flow – green are Merrimack sub-

basins, pink are Concord sub-basins


Considered when locating recharge facilities

MERRIMACK

WATERSHED

Alternative

recharge area

1.5 miles away

Suitable

recharge area

within study

area

72 acres within

Zone III. Mix of

I-495 DOT and

developer land

Minimizing Financial Risk - Phasing

Reducing carrying costs by using technologies that are

affordable at small scale and then installing capacity in

phases to match growth

Large carrying

costs – higher

risk of tax

increase to

subsidize user

rate

Small carrying

costs – reduced

risk to tax base

and user

Minimizing Financial Risk - Phasing

Phase 1 2 3 4 5 TOTAL

Year 0 5 10 15 20

Flow (gpd) 30,000 38,000 61,000 23,500 29,500 182,000

Anticipated Connections 100 127 203 78 98 607

Capital Cost ($) 4,182,400 3,610,302 6,718,555 3,000,544 4,366,569 21,878,371

Sewer Length Required (LF) 18,200 6,333 10,167 3,917 4,917 43,550

Area Required (acres) 1.67 2.11 3.39 1.31 1.64 10.12

TOTAL

Year 0

Flow (gpd) 182,000

Anticipated Connections 607

Capital Cost ($) 17,024,590

Sewer Length Required (LF) 43,550

Area Required (acres) 9

Smart Phasing

Conventional Phasing Assumptions:

•Includes cost of: onsite appurtenance, collection, secondary treatment and groundwater dispersal

•Does not include cost of land

•In both scenarios the majority of land is required for dispersal

•Treatment costs based on the ability to achieve secondary treatment at $20/gpd installed between scale of 23,500 and 182,000 gpd by using available technologies

Minimizing Risk – Private ownership

Design-Bid-Build

Conventional Approach

(implementation through

public ownership)

Design-Build-Operate-

Finance

(implementation through

private ownership)

Design Build

Design Build Cost Town Private Entity

Schedule Completion Town Private Entity

Construction Warranty Town Private Entity

Asset Management

Compliance Guarantee Town Private Entity

Capital Replacement Town Private Entity

O&M Cost Town Private Entity

Residual Disposal Cost Town Private Entity

Life Cycle Cost Town Private Entity

FinanceLong-Term Financing Town Private Entity

Interest Rate Risk Town Private Entity

Risk Allocation Table: Private vs. Public Ownership

Cost of private debt will result in higher user rates but will remove

the risk to the tax base

Minimizing Risk – Private Ownership

Conventional WW Ownership Options in MA:

• Governmental - Municipal/County

• Quasi-Governmental Authority, Special District, Public Nonprofit

• Private Nonprofit Cooperative or Association

Alternative WW Ownership Options in MA:

• Private For-Profit Utility

• Public Private Partnerships – P3

Minimizing Risk – Private ownership

Private For-Profit Utility:In MA Private wastewater entities are not regulated by the

Department of Public Utilities. MassDEP regulates Privately

Owned Wastewater Treatment Facilities (PWTF) under 314 CMR

5.15 based on conditions which are aimed towards Homeowners

Associations etc.

Public Private Partnerships (P3):The town retains ownership and transfers operation and financial

obligations to a private entity under a long term contract,

generally 20 years or longer. It appears that special state

legislation would be required for a municipality to procure a

design-build-operate type contract.

Responsible Management of Infrastructure

17

Ownership/Financing-Debt/Equity

Design Construction

Existing Utility/ Govt EntityAssociation/Co-Op/etc

IPP WWTP – Co-Owned by SPV

Responsible Management Entity

(RME) $

ServicesFees $

GroundLease/SiteServices

Design Build

Operations Repair & Replace

Own/Operate

Regulators

RME Assets

$

Water/Energy/Nutrient

Services

RME – Decentralized water reuse in MA

MA Case Study: Gillette

Stadium

• MBR technology with design flow of 1.3 MGD. Capital cost in

2005 was $5.2M

• Recycles flush water from 69,000 football fans on game day.

• Sewer enabled economic expansion around the stadium –

multi-user private for-profit utility operation

• 20 year DBO contract with performance risk – reduces

recharge by reuse

Appropriate Technology

Subsurface Flow

Treatment WetlandsPackaged Activated

Sludge Process systems

Relationship between capacity in gallons per day (gpd) and unit capital cost ($/gpd capacity) for five small-

scale wastewater treatment technologies: Activated Sludge Plant (ASP), Sequencing Batch Reactor (SBR),

Oxidation Dith (Oxi-Ditch), Membrane Bioreactor (MBR) and Subsurface Flow Treatment Wetland (SSF TW).

Capital costs for small-scale treatment technologies


Relationship between capacity in gallons per day (gpd) and unit operating cost ($/1000 gallons treated) for five

small-scale wastewater treatment technologies: Activated Sludge Plant (ASP), Sequencing Batch Reactor (SBR),

Oxidation Dith (Oxi-Ditch), Membrane Bioreactor (MBR) and Subsurface Flow Treatment Wetland (SSF TW).

Subsurface

Flow

Treatment

Wetlands

Packaged

Activated Sludge

Process systems

Operating costs for small-scale treatment technologies


“The system is not an unsightly eyesore, does not emit

odors and emits no loud noise”

Subsurface technologies Open surface technologies


Landscape architecture - Flower and the Butterfly

Constructed Wetland at Ko Phi Phi, Thailand

http://mit.biology.au.dk


Courtesy of Worrell Water

Indoor natural systems that achieve reuse

Advanced Treatment with Natural Systems

Living Machine by Worrell Water TechnologiesPort of Portland building, OR


Cost and carbon metrics for different collection

systems COLLECTION SYSTEM SUMMARY

(based on a full build out 182,000 gpd system)

Type of

Collection

Capital

Cost ($)

Operating Cost

($/yr)

Pot. Energy

Production

($/yr)

Pot. Tipping

Revenue

($/yr)

Net

Operating

Cost ($/yr)

Net Carbon

Footprint

(T CO2Eq/yr)

STEP $9.1M $87,360 $5,232 $19,700 $62,428 1,540

GRINDER $11.2 M $222,768 $20,614 $0 $202,154 469

GRAVITY $9.4 M $102,757 $20,156 $0 $82,601 379

STEP SEWER PREFERENCE - 56 points. “The cost to build the system has no impact on your current property tax rates or existing utility bills”. Lower net operating costs will reduce risk by improving ability to cover cost of debt

GRAVITY SEWER PREFERENCE - 26 points. The system does not produce large amounts of solid, liquid or gaseous waste that requires disposal in landfills or subsequent treatment systems. Anaerobic digestion in septic tanks releases methane which has a high global warming potential.

Centralized vs. decentralized?

Costs of decentralized

and centralized can be

comparable. Available

locations for

discharge governs

economic feasibility.

Flow

(gpd)Users

Total Cost ($

2010)$/gpd inst $/User

Fraction of cost

in collection

Typical user

rate ($/gal)*

MN Decentralized

System20,770 38 1,476,364 $ 72.83 $ 38,851 23% $ 60

Littleton

Proposed182,000 607 12,245,188 $ 67.28 $ 20,173 28% $ 70

Ph 1 and Ph 2

Proposed1,800,000 8400 262,000,000 $ 169 $ 36,190 66% $ 63

Cape: Feasible locations for decentralized

discharge

Zone II recharge requires less than 3 mg/L TOC. Needs advanced tech not affordable at decentralized scale… get out of Zone II if possibleFrom Sterns and Wheler CWMP

Improving Affordability

Integrate infrastructure to turn waste into resources which can

provide a source of revenue to offset sewer costs

WATER

POWER

FOOD

COLLECTION

TREATMENT

DISPOSAL

RESOURCE

SUPPLYWASTE

PROCESSING

FROM

OUTSIDETO OUTSIDE

CARBON

DOLLARS

WATER

NUTRIENTS

Improving Affordability

2.0 Dry Ton

ANAEROBIC

DIGESTER

WETLAND

TREATMENT

STEP

COLLECTION

SYSTEM

REUSE WATER

DISCHARGE

POWER

607 EDU

COMMUNITY

FERTILIZER

2.74 Tons

food waste

4,100 gpd

sludge 182,000 gpd

85,000 gpd

97,000 gpd

-$16/EDU month-$14/EDU month-$6/EDU month

2,600 kWh

Integrate infrastructure to turn waste into resources which can provide a

source of revenue to offset sewer costs

Improving Affordability – water reuse

Can reduce potable water needs by 40% and save on utility costs

REUSE NETWORK NATURAL TREATMENT SYSTEM

Improving Affordability – Energy Integration

Dry COD

(tons/day)Capital Cost ($)

O+M cost

($/yr)kWh/yr

Revenue

Tipping Fees

($/yr)

Revenue

REC sales

($/yr)

Revenue

Power sales*

($/yr)

Net

Operating

Profit ($/yr)

0.5 1,801,584 7,500 238,710 36,875 3,581 17,903 50,859

1 2,362,095 15,000 477,419 73,750 7,161 35,806 101,718

2 3,016,601 30,000 954,838 147,500 14,323 71,613 203,435

3 3,832,880 45,000 1,432,257 221,250 21,484 107,419 305,153

5 5,192,057 75,000 2,387,095 368,750 35,806 179,032 508,589

Survey priority number 3: “Reduce waste disposal”:

Anaerobic digester to produce electricity from organic waste.

•Multiple revenue sources

•Economic feasibility depends on local availability of waste

•Littleton has Rate 71 to enable purchase from micro-generators

Assumes power is sold to Littleton Electric Light Department at 0.07 $/kWh and REC value is 0.015 $kWh

Source Type of Source Tons per year Chemical

Oxygen Demand

Smart sewer network Projected Wastewater Solids 112*

Littleton Septage Residential Septic Systems 438

Littleton Food Waste Residential Food Waste 218

Nashoba Valley Life Care Center Institutional Health Facility 12

Tre Amici Restaurant 9

Yangtze River Restaurant Restaurant 8

Donelan’s Supermarket Grocery Store 27

TOTAL 711

Data for non-residential sources from Draper/Lennon, Inc., 2002, Identification, Characterization, and Mapping of Food Waste

and Food Waste Generators in Massachusetts.

Additional sources exist in town not accounted for in this table include schools and Veryfine Sunny Delight Food Processing.

Veryfine produces 6,000 tons per year of Chemical Oxygen Demand but this is not readily available. There are 235 food waste

generators within a 10 mile radius of the study area that produce 16,000 Tons per year of food waste

Survey performed to identify realistic local availability of organic

material (approximately 2 dry tons COD per day).

Improving Affordability – Energy Integration

Economic Feasibility Analysis – Public

Ownership

SCENARIO PHASING

PRIVATE

DEVELOPER

CONT.

SOURCE OF

FINANCING

COST OF

LAND

($/SF)

HOOK

UP FEE

($)

SUBSIDY

FRACTION OF

BUILD-OUT

ACHIEVED

PHASE 1 CAP

REQ FROM

FINANCING

($)

TYPICAL

USER RATE

($/MON)

RISK OF

TAX

INCREASE

Baseline Smart $2M Municipal 0 5,000 BG+TF+WR 100% 7,078,381 37 LOW

Conv. Conv. $0 Municipal 2 13,000 None 100% 11,578,240 101 HIGH

1 Conv. $2M Municipal 0 5,000 BG+TF+WR 100% 14,239,768 78 HIGH

2 Smart $0 Municipal 0 5,000 BG+TF+WR 100% 9,078,381 43 LOW

3 Smart $2M Municipal 2 5,000 BG+TF+WR 100% 7,193,581 38 LOW



6 Smart $2M Municipal 0 5,000 None 100% 2,182,400 70 LOW

7 Smart $2M Municipal 0 5,000 WR 100% 3,869,438 56 LOW

8 Smart $2M Municipal 0 5,000 BG + TF 100% 5,391,344 51 LOW


10 Conv. $2M Municipal 0 5,000 BG+TF+WR 50% 13,883,221 127 V HIGH

Economic Feasibility Analysis – Private Ownership

SCENARIO PHASING

PRIVATE

DEVELOPER

CONT.

SOURCE OF

FINANCING

COST OF

LAND

($/SF)

HOOK

UP FEE

($)

SUBSIDY

FRACTION OF

BUILD-OUT

ACHIEVED

PHASE 1 CAP

REQ FROM

FINANCING

($)

TYPICAL

USER RATE

($/MON)

RISK OF

TAX

INCREASE

Baseline Smart $2M Municipal 0 5,000 BG+TF+WR 100% 7,078,381 37 LOW

Conv. Conv. $0 Municipal 2 13,000 None 100% 11,578,240 101 HIGH

1 Smart. $2M SRF 0 10,000 BG+TF+WR 100%7,078,381

90 NONE

2 Smart $2 M Private 0 10,000 None 100%7,078,381

148 NONE

• High-capital cost of biogas and water reuse and low hook-up make less

sense under private financing

• Rates are 4 times higher if risk is completely removed from tax-base

and only those that are served by the system have to pay for the

system

• SRF provides an affordable way of removing risk from the town

Conclusions for Littleton

• System designed to remove risk to tax-base, minimize waste, be affordable and non-offensive

• At small scale natural systems and STEP sewer were most affordable.

• This enabled modular, low-risk expansion

• Subsidy via biogas and water reuse provides a very affordable service if public financing is secured

• These subsidies are not affordable if private finance is used to remove all risk to tax-base

• A P3 or SRF funded project will allow the best of worlds but will require special legislation

Relevance to Cape Cod

Cape Cod Commission presentation in April, 2011

Feasibility of a

green and

decentralized

treatment

network for the

Cape needs

studying.

Relevance to Cape

• Green tech (and other tech) that performs enhanced nutrient removal is affordable at scale of decentralized-utility

• Proper feasibility study of decentralized sewer costs versus disposal options should be performed – need to get out of Zone II discharge

• Mechanism for RME to provide long-term operations, risk management, ownership and financing exists in MA. An economic feasibility study would be required

• RME can configure utility to single goal of the region. DBO is key for the RME to undertake risk

Relevance to Cape

• Solution for Littleton was tailor-made to needs of the town

• Motivations in the Cape are different

• Natural systems are affordable at small-scale and can be phased according to priorities

• Decentralized sewer costs should be based on the right sewer technology and specific scenario

• Economic advantage of subsidy, alternative ownership and management should be investigated

Littleton, MA Littleton, MA –– Smart Sewering Strategy:Smart Sewering Strategy:

Affordable Green Sewering, FitAffordable Green Sewering, Fit--ForFor--PurposePurpose

Thank you for your attentionThank you for your attention

Green First:

December 8, 2011 Falmouth MA

Decentralized systems are not new

Salveson et al. report on about 240 small-scale systems.

There are many more

Map adapted from information presented in:

Salveson A., Zhou, Z., Finney B.A., Burke, M., Chan Ly, J., 2009, Low-Cost Treatment

Technologies for Small-Scale Water Reclamation Plants, Water Reuse Foundation

Advanced Treatment with Natural Systems

SAGR with patented FBA technology, by Nelson Environmental CanadaSteinbach Manitoba Aerated Lagoon nitrogen polishing

RME - Distributed utility in MN

Morrison Mille

Lacs

Pine

Kanabec

Benton

IsantiChisago

Anoka

Sherburne

Washington

Meeker

Wright

Mc Leod Carver

HennepinRamsey

Scott

Dakota

Sibley

St. Paul

Minneapolis

RME Distributed utility in MN

Typical range of monthly user fees for 21 systems

RME - Waste to energy in NJ

Ridgewood, NJ

– Retrofit

existing plant

to be carbon

neutral

• DBOF P3 with Middlesex water with buyout option. Utility

assumes all performance risk

• Optimizing Renewable Energy via Solar + Internal and

External Carbon Sources. Goal = Net Zero Energy

Littleton, MA –Smart Sewering Strategy: Affordable Green ... Knowles... · Operations Repair &...

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