Compost for Green Infrastructure

Compost for Green Infrastructure

Buildings in the US account for nearly 25% of all the water consumed in this country, 40% of the municipal solid waste, 50% of all greenhouse gas emissions, 30% of all virgin wood and raw materials use, and 40% of all energy use (75% if you include transportation between buildings) according to the US Green Building Council (USGBC).

LEED – Leadership in Energy and Environmental Design – is an internationally recognized green building program. It provides building owners and operators with a framework for identifying and implementing practical and measurable green building design, construction, operations, and maintenance solutions.

This program created and administered by the USGBC is a point accrual and rating system that promotes and certifies environmentally sustainable building projects to create a national standard, through third party verification, to increase the value of green buildings in the marketplace.

Higher levels of certification have been correlated to higher real estate values, lower operation and maintenance costs, higher worker productivity and attendance, and even greater rent revenues. Increasingly, municipal, and federal government agencies are requiring new public buildings be LEED Certified. The square footage registered and certified under the LEED green building program has increased from 80 million in 2002 to 8 billion in 2008. This currently represents approximately 3% of the total US building construction market. This growth rate, coupled with an even higher ceiling, and strong support from the administration has made companies of all sizes and market sectors clamor for a foot in this field.

Compost has many green benefits including preventing erosion, conserving water, and promoting healthy vegetative growth. LEED has recognized compost’s benefits and has created specifications for its application on LEED-certified buildings. These resources help builders and landscape architects to implement more green building practices, while getting the coveted LEED-seal of approval.

Compost-based products contribute to the following categories under LEED rating system: Sustainable Sites, Water Efficiency, and Materials and Resources.

Sustainable Sites (SS) is a category divided into 15 sub-categories, although only 5 provide credits where compost BMPs can contribute to a maximum of 5 credits, and 1 prerequisite.

SS Prerequisite 1 (0 credits) Construction Activity Pollution Prevention requires erosion and sediment control practices that comply with minimum requirements for NPDES Phase II and state and local regulations. Although no credits are awarded, this is a prerequisite, and compost BMPs can be applied.

SS Credit 5.1 (1 credit) Site Development: Protect and Restore Habitat awards a credit for the preservation or restoration of site wildlife habitat. If the site is a greenfield (undeveloped) the plan must preserve 50% of the undisturbed area; if the site has been previously developed the plan must restore native habitat to 50% of the site area.

Compost products have been widely used for land and ecosystem restoration projects. Compost uniquely restores above and below ground biodiversity and habitat which is essential to plant community health and ecosystem function and sustainability. Most compost-based products are 100% biodegradable and manufactured from organic materials native to the bioregion where they will be applied; making these products uniquely indigenous to the native wildlife and habitat restoration project. Additionally, these products will not disrupt wildlife migration patterns and will not trap wildlife.

SS Credit 6.1 (1 credit) Storm Water Design: Quantity Control awards a credit for reducing site storm water. Sites with less than 50% impervious surface area must maintain post-development site hydrological peak runoff rate and volume to pre-development conditions based on a 2 yr-24 hr storm; or reduce peak flows to receiving stream channels and prevent their erosion and sedimentation utilizing natural systems that include native or adapted vegetation.

For sites with greater than 50% impervious surface area a credit is awarded by reducing site storm water volume by 25% based on a 2 yr-24 hr storm event. Compost based Low Impact Development management practices have been widely used to greatly reduce site storm water volume, peak flow rates, and stabilize stream banks and channels using natural materials native to the site bioregion.

SS Credit 6.2 (1 credit) Storm Water Design: Quality Control awards a credit for on-site treatment of post-construction storm water resulting from 90% of the average annual rainfall (from historical records) or reducing 80% of the average annual TSS load. Compost technologies, such as compost storm water blankets and bioretention systems, have been used to target runoff volume reduction, which reduces TSS loads; and can be used to filter and trap TSS from storm water through the compost sock and stormwater pollutant trap applications. These compost-based Low Impact Development management practices are specifically designed for these types of applications.

SS Credit 7.2 (1 credit) Heat Island Effect: Non-Roof awards a credit for minimizing the negative effects of site and building microclimate by reducing hardscape features that increase heat, not pertaining to the roof. The site plan must provide a minimum of 50% shade to site hardscapes 5 years after occupancy. Most compost products can assist in growing rapid, healthy and sustainable site vegetation used to shade area hardscapes which can contribute to this credit.

SS Credit 7.2 (1 credit) Heat Island Effect: Roof awards a credit for minimizing the negative effects of site and building microclimate by reducing roof features that increase heat. Vegetated roof systems have been widely used to insulate buildings and to assist in minimizing contributions to the urban heat island. The building design must have 50% of the roof area utilizing a green roof system or the majority of the roof area must use a combination of a green roof and highly solar reflective materials. Using compost media in green roof systems can improve vegetation establishment, health, and sustainability.

Water Efficiency (WE) is category divided into 5 subcategories, where 3 provide credits which compost products/practices may contribute toward a maximum of 3 credits.

WE Credit 1.1 (1 credit) Water Efficient Landscape: Reduce 50% awards a credit for reducing landscape irrigation from potable water sources by 50% based on a mid-summer usage baseline. Compost has a high water holding capacity and can hold up to five times its weight in water. Increasing soil organic matter content using compost engineered soils or surface applied compost blankets may contribute to this credit. For every 1% increase in soil organic matter, plant available water is increased by 16,500 gal per acre foot of soil (compost is generally 50% organic matter, dry weight basis). If applied as a compost blanket it can hold approximately 1450 cubic feet of water and decrease water loss by reducing surface evaporation. By reducing evaporation and increasing water holding capacity through the use of these compost-based products, irrigation requirements can be greatly reduced. Agricultural research has shown minimal applications of compost can decrease irrigation requirements by 30%.

WE Credit 1.2 (1 credit) Water Efficient Landscape: Reduce 100% awards an additional credit to WE Credit 1.1 for eliminating permanent irrigation equipment (temporary irrigation can be used for 1 year post-construction for vegetation establishment). Increasing the application rate of compost blankets or the compost inclusion rate of an engineered soil system can further increase water holding capacity and reduce evaporation.

WE Credit 2 (1 credit) Innovative Wastewater Technologies awards a credit for reducing potable water use in building toilet systems or by reduction of wastewater discharge through on-site treatment. Compost has been widely used as a substrate with plant materials in water biofiltration systems and constructed wetlands used to treat wastewater, increase infiltration, adsorb/bind pollutants, and recharge aquifers and ground water systems. Composting toilet systems have been utilized to reduce potable water use to attain this credit.

Materials and Resources (MR) is a category divided into 14 sub-categories, where 5 provide credits that compost products/practices may contribute to a maximum of 5 credits.

MR Credit 4.1 (1 credit) Recycled Content: 10% awards a credit for using pre-consumer and post-consumer recycled materials in the building project. Ten percent of the materials (determined on cost basis) in the building project must be of recycled content. Higher value is given to materials made of post-consumer recycled content. Compost is 100% recycled and can be made from pre-consumer and/or post-consumer materials.

MR Credit 4.2 (1 credit) Recycled Content: 20% awards an additional credit to MR Credit 4.1 for increasing recycled materials in the building project to 20%.

MR Credit 5.1 (1 credit) Regional Materials: 10% awards a credit for using materials that are extracted, recovered, or harvested, and manufactured within 500 miles of the building project to reduce the negative impacts from transportation and support use of indigenous resources and local economies. Products that meet these criteria must account for ten percent (cost basis) of building materials. Due to the bulk and weight of compost feedstock materials and end products, these materials are rarely collected or distributed over 200 miles.

MR Credit 5.2 (1 credit) Regional Materials: 20% awards an additional credit to MR Credit 5.1 for increasing defined regional materials to 20% (cost basis) of building materials used in the project.

MR Credit 6.0 (1 credit) Rapidly Renewable Materials awards a credit for using building materials made from sources that are renewable in 10 yrs. These materials must account for 2.5% (cost basis) of the materials used in the project. Compost is a rapidly renewable resource that is continually manufactured from organic materials often harvested or collected in much less than 10 years.

For more information, visit USGBC homepage | U.S. Green Building Council


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