The Western Wayne School District in Wayne County, Penn., needed to replace two, smaller, aging elementary schools with a new building to consolidate student and staff populations and lower operating costs. To participate in available incentives in the state funding of public school construction, the project needed LEED Silver certification or higher. Along with a pleasant, energy and water efficient building, the school district also wanted to create a learning environment fostering environmental awareness and stewardship.

The new Evergreen Elementary School, designed for up 900 students and 100 staff, is approximately 90,000 square feet including classrooms, a library, cafeteria, gymnasium and administrative space. Key design features include:

·  Design centered on energy efficiency, day lighting and inviting atmosphere.

·  Geothermal heating and cooling system

·  Living Machine System for wastewater treatment and recycling

 

Overall Project Challenges

Initially, district residents were resistant to the project due to perceived financial burdens. The project team led by, Burkavage Design Associates (BDA), developed innovative approaches to reduce construction costs and minimize operating costs. However, education of the school district, the public and some regulators was required to gain acceptance of the proposed technologies and approaches.

Overall construction cost, including site development, was $19,261,000. Due to a favorable bidding climate, final bid results were 18 percent below the cost estimates completed just months before.

Available land parcels were not served by sewer and thus required onsite wastewater management. Because area soils had low infiltration capacity, traditional land disposal of wastewater would require very large parcels. The Pennsylvania Department of Environmental Protection (DEP) suggested a wastewater system that allowed recycling and reduced disposal area making the desired parcel feasible for onsite management. A Living Machine System delivered necessary effluent quality in a modest footprint, provided educational opportunities, and fit overall design objectives.

The school district and the project civil engineering firm, Greenman Pederson Inc. (GPI) contacted Worrell Water Technologies LLC (WWT) to explore the Living Machine system approach. Owners and regulators had concerns about performance and reliability as well as odors and public contact. Dave Maciolek, PE, then senior engineer at WWT, now principal engineer at Aqua Nova Engineering, used his experience with similar projects to overcome concerns.

To meet cost and energy use objectives, the team maximized energy efficiency by employing geothermal heating/cooling, ventilation energy recovery system, superior building envelope and use of natural daylight. Design of these aspects directly affected architecture, especially floor-to-floor height, shape of classrooms, location of utility services, and plumbing throughout the building. Thus, HVAC and daylight harvesting informed the architecture rather than conforming to building design.

EvergreenSchoolDesign Details

All school wastewater (7,000 gpd maximum) flows into a primary tank to remove coarse solids and is then pumped to the Tidal Flow Wetland Living Machine System where pollutants are biologically removed. Wetland effluent is chlorinated and then flows to an effluent storage tank and is pumped to a reclaimed water system (with further UV disinfection) to flush all toilets in the school. Treated effluent beyond flushing demands overflows to an irrigation disposal system with reuse benefits.

All treatment components are located in a greenhouse except the primary and effluent tanks, located underground near the greenhouse. Housing the Living Machine System and critical components in a greenhouse, allows easy, year-round access and creates an educational tool.

School wastewater is concentrated and highly variable in flow. Tidal Flow Wetland technology utilizes attached-growth microbes that provide effective treatment with very low energy in a compact footprint. In addition, this technology handles frequent, wide variations in loading typical of schools with weekends, holidays and extended breaks.

The school site area and poor soils made it unsuitable for a conventional soil-adsorption disposal system. GPI designed the disposal system based on vegetative demand and evaporation only. The seven-acre disposal system, including some of the athletic fields and forested areas, does not rely on any infiltration of the effluent beyond the plants’ root zone.

Irrigating with treated effluent benefits the environment and school district. Most nitrogen and phosphorus in the reclaimed water are assimilated by the grass or adsorbed to the soil, minimizing both nutrient discharges to the watershed and fertilizer use.

The building was designed to be energy and cost efficient yet human and earth-friendly.  An excellent thermal building envelope is provided through permanent insulated concrete form (ICF) bearing wall construction along with high performance windows, glazing and roofing systems. The entire shell also contributes to exceptional acoustic performance, eliminating distracting exterior sounds from classrooms.

Dry-polished concrete floors throughout common spaces are easily cleaned and require no annual stripping and refinishing. Remaining flooring systems include no-glue carpet tile, recycled porcelain tile, and linoleum sheet flooring. Additionally, zero-VOC paints, recycled glass wall tile, and FSC-certified lumber were used.

Bright and friendly spaces are achieved with energy-efficient daylight harvesting, light colored material finishes, proper proportion and orientation of rooms and attention to location and size of windows. Highly reflective light shelves redirect natural light deeper into perimeter spaces and exterior sunshades reduce solar heat gain and glare in classrooms.

A geothermal system provides all heating and cooling. The closed loop system consists of a geothermal field, circulation pumps and water source heat pumps (one per classroom). Seventy-two geothermal wells (approximately 500 deep) transfer heat to/from the earth, heating the building on the coldest days without fuel-fired boilers.

Outdoor air exchange utilizes energy-recovery, dedicated outdoor air systems, allowing generous fresh air supply with minimal energy losses. Advanced building automation allows multiple subsystems to be controlled through a single computerized system, enabling easy optimization for different seasons and usage loadings.

Conclusions

The team created a friendly, efficient and cost effective school by selecting good design goals, working creatively and incorporating appropriate technology. Extra effort was required to develop these new approaches and to convince stakeholders that the innovative systems were not only sound but also cost effective.

EvergreenElementary SchoolProject Team

Project name: Western Wayne Evergreen Elementary School

Project location: Lake Ariel, Penn.

Completion date: August 2011

Architect: Burkavage Design Associates LLC, Todd Wescott

Civil Engineer: Greenman-Pederson Inc., Gary Cavill, PE

Wastewater treatment/recycling: Worrell Water Technologies LLC and Aqua Nova Engineering

Engineering, PLC: David Maciolek, PE, Aqua Nova Engineering

Owner contact: Superintendent, Andrew Falonk

Facilities operator: Paul DePrimo