Colorado produces about99,000 dry tons of sludge annually.

Colorado imports about 34,000dry tons of sludge annually.

After processing, Colorado uses about 102,000 dry tons of sludge beneficially each year.

Colorado Biosolid Use: 2007

land application

reclamationrangeland

transfer

landfill

stored

composting

57%

17%

9%

8%7%

1.5%0.5%

productive uses of wastewater sludge

N

Denver

Boulder

Greeley

Fort Collins

productive usesdesign prototype

regional networkparameters

Composted biosolids go through a cycle of three stages; mixing, composting, and curing. Once the composted biosolids are curated, the soil is ready for sale and distribution. From star t the finish, a single load of sludge takes approximately six weeks to complete the composting cycle.

Denver ’s wastewater reclamation facility processes up to 140 million gallons of water daily, resulting in the production of 68 dry tons of sludge. The current sludge pro-cessing procedure, anaerobic di-gestion, of biosolids at the Denver facility requires large amounts of energy resulting in annual produc-tion costs of over a million dollars. With increasing population in the South Platte River Basin, energy use at wastewater facilities is ex-pected to increase.

Composting sludge is one of the most productive ways to cut on

down on energy use in wastewater treatment processes. By switching from the conventional anaerobic process to a composting system, thousands of dollars can be saved every year. Not only does com-posting reduce energy use and costs, but composted biosolids are productive in a variety of ways. Composting facilities help to reduce greenhouse gas emis-sions that are produced during the anaerobic digestion process. Com-monly, composted biosolids can be applied to agricultural land to restore eroded soils and degraded crops, yet compost can be used to

fer tilize household lawns, remedi-ate brownfields, restore wetland habitats, and cap landfills.

KrapPARK is a project that pro-poses a system of composting facilities to create a more energy efficient wastewater treatment process. The compost web follows sludge from the beginning until final distribution to productive uses focusing in the Boulder, CO area. The network is easily replicable and can be linked to other waste-water facilities creating an energy efficient and productive landscape.

Metro Wastewater Reclamation District, Denver, CO

210,000,000 gallons of water distributed daily by Denver Water

140,000,000 gallons of wastewater treated daily by Metro Wastewater Reclamation District

350 gallons of water used daily by a single family home

Energy Use

29 kWh dailyaverage home consumption

24189 kWh dailysecondary wastewater process 834 homes

KrapPARK Regional Compost Center is located ten miles east of downtown Boulder and is the first phase of the proposed composting network. KrapPARK mixes sludge from Boulder Wastewater Treatment

Facility on site, as well as green waste delivered by the public. The mixture is composted and con-ver ted into nutrient rich soil that is later sold for use by both public and private entities. KrapPARK is a

unique facility because it involves members of the community which facilitates sustainable solutions for waste disposal and productive uses for wastewater byproducts.

Boulder Wastewater Treatment Facility

Boulder Composting Network

Captain Jack Mine Reclamation Site

Waldon Ponds Wildlife Habitat

Denver Regional Landfill

Boulder Regional Compost Center

ParkPark

TOILET SEWER PRODUCTIVE USESWASTEWATER FACILITY COMPOST FACILITY

Landfill CappingComposted biosolids have the most suitable structure for landfill capping projects.

- The soil structure allows for appropriate root penetration to help prevent leachate problems

- Composted soils have the richest amount of nitrogen and other nutrients to provide optimal growing conditions

- Capping with compost in evapotranspiration caps allows for the waste and garbage to decompose below the sur face

methane uses

LANDFILL CAPPING::composted sludgerestoring landfills with municipal wastewater byproducts

methane collectionlandfill gas contains 50% methane and 50% CO2 allowing energy collection and production

1 acre of capped landfill = 712 kWh daily

powers 10 lightbulbs for 712 hours

electricity

heating

pipeline qualitysynfuel

uncovered full landfill

landfill capped with composted soils

GARBAGE

GARBAGEGGEE

opportunities for public open space

Fresh Kills ParkStaten Island, New Jersey

Hiriya ParkTel Aviv, Isreal

Hassell Millenium ParklandsSydney, Australia

2200a c r e s

2000a c r e s

1100a c r e s

capped landfill

ONE acre of capping methane

emissionsplanting 11,667 acres of trees

removing 8,334 cars from the road

preventing the use of 101,331 barrels of oil

=

or

environmental impactsGREENHOUSE EMISSIONS

or

garbage

foundation

composted soils

Evapotranspiration Cap

Composting WebAt a regional scale, the project consists of a rhizomatous

web of linkages between existing wastewater treatment facilities and proposed composting facilities. The composting

facilities are strategically placed near transportation infrastructure and agricultural lands, as well as centralized among existing

wastewater treatment facilities state-wide. The composting nodes facilitate the collection, distribution, and productive uses of wastewater

byproducts for both public and private entities.

Biosolids are treated sewage sludge that meets the EPA pollutant and pathogen requirements for land application and sur face disposal.

Composted BiosolidsComposted biosolids are organically rich soils that contain a well-balanced array of micronutirents that are capable of conditioning degraded soils through land application.

Sludge refers to the residual solid or semi-solid material separated from wastewater during wastewater treatment processes.

Sludge Biosolids

Composted biosolids are an effective method of remediating toxic soils contaminated by industrial pollution because they:

- Increase soil fer tility

- Correct soil pH levels

- Improve physical proper ties of soil

Oxygen

K Mg Na SFeP,NCa

C

Al

Si

Mg AlSK

Oxygen

Carbon

Na FeP

N

H

Ca

Si

Carbon

Oxygen

K Mg Na SFeP,NCaAl

Si

Mg AlSK

Oxygen

Na FeP

N

H

Ca

Si

Average Soil Composted Biosolids

Brownfield Reclamation

evapotranspiration

Polishing Wetland

microbes(biofilm)

benthic layer

south platteriver

treatedwastewater

compostedbiosolids

Composted biosolids can be used in the production of floating wetland islands that are used to restore wetlands.

- Islands act as a water purifier, collecting toxins from the polluted wetland

- Wildlife habitats are restored through the addition of floating islands

Composted Biosolid Island

Wetland Restoration

Transportation Network

Denver

Boulder

For t Collins

Greeley

Composting facilities are located nearby transpor tation infrastructure to ensure efficiency and convenience in the collection of wastewater byproducts and the distribution of composted biosolids throughout Colorado.

N

Highways

Railroads

Soil Water Capacities

Because the application of composted biosolids to a soil increases the available water capacity, which helps plants survive longer in droughty conditions, the composting facilities are strategically located on or near soils with low available water capacities.

N

0.00-0.020.03-0.090.10-0.140.15-0.170.18-0.20

Crop Nitrogen Requirements

Agricultural crops require varying amounts of nitrogen in their soils. Because additional micronutrients can be added into the biosolid mixture, composted biosolids are an effective method of providing nitrogen to crops. For this reason, the composting facilities are located near agricultural lands.

Low High

N

Composting Web

The proposed composting facilities are also located near existing wastewater treatment plants to facilitate the exchange of wastewater byproducts to be conver ted into useful products by the composting facilities.

Existing Wastewater Treatment Facilities

Proposed Composting Facilities

N

Captain Jack Mine Reclamation Site Denver Regional Landfill Waldon Ponds Wildlife Habitat

grit basin

wastewater

aeration basinsprimary clarifier

secondary clarifier

chlorination/dechlorination

anearobic digestion

river water

biosolid fertilizer

biosolid fertilizerbiosolid composting pile

biosolid soil

river water

wetland dechlorination

dewatering clarifier

Wastewater Treatment Cycle

Conventional Sludge Treatment Process

Proposed Sludge Treatment Process

Benefits of Sludge CompostingAs Compared to Conventional Anaerobic Digestion Processes

68.50

1,253.55$100.28

$36,602.00

dry tons dailydaily kWhdaily expensesyearly expenses

Proposed ProcessAerated Pile Composting18.3 kWh per dry ton

68.5038,360

$3,038.80$1,120,112.00

dry tons dailydaily kWhdaily expensesyearly expenses

Current ProcessAnaerobic Digestion560 kWh per dry ton

daily electrical savingsdaily monetary savingsyearly monetary savings

37,106 kWh$2,938.52

$1,072,370.00

Savings

Sludge Processing

Colorado produces about99,000 dry tons of sludge annually.

Colorado imports about 34,000dry tons of sludge annually.

After processing, Colorado uses about 102,000 dry tons of sludge beneficially each year.

Colorado Biosolid Use: 2007

land application

reclamationrangeland

transfer

landfill

stored

composting

57%

17%

9%

8%7%

1.5%0.5%

Colorado impor ts about 34,000 dry tons of sludge annually.

After processing, Colorado uses about 102,000 dry tons of sludge beneficially each year.

Sludge Importing 2007 Biosolid Use in Colorado

ParkPark

IncentivesAffiliate with Trash Tax in Boulder to support entities transitioning to zero waste

Establishing a program that trades compost for public waste

Create grants to support research at compost facilities

Government tax breaks for reducing greenhouse gas emissions

Weeks 4-7

Weeks 8-11

Weeks 12-15

Weeks 1-3

Composting CycleRaw Sludge MixCuring of CompostFinal Composted Biosolids

Goals & ObjectivesReduce energy requirements through alternative sludge processing

Reduce greenhouse emissions and landfill disposal of sludge and biosolids

Reduce imports of biosolids to the South Platte River Basin

Engage community through interactive green waste sorting and composting processes

Utilize productive uses for composted sludge -Agricultural Application -Brownfield Reclamation -Landfill Capping -Wetland Restoration -Residential application

N

CirculationPublicDelivery TrucksComposting Equipment

Public CompostCenter

Sludge MixingCenter

Aerated Blower

Per forated Pipe

Air Circulation from Blower

Raw Compost Mixture

Finished Compost

Compost Distribution

Center

Recycling Center

ParkParkComposting Center Prototype

Aerated Static Pile

Aerated StaticComposting Piles

Rachel Barth & Kylie Harper | LAR 648 Mile High Water: Design Strategies for Denver’s Drylands | Professor Canfield | Kansas State University | Fall 2011