Home Sustainable Land Development Today February 2005

Sustainable Technology Paying Off

Written by Greg Yoko

Wednesday, 02 February 2005

Mississippi State: Practicing what they preach One thing is certain—Mississippi State University’s Landscape Architecture Department is putting their mission statement into practice. The primary goal of the program is to incorporate sustainable design through applied technology, which they have certainly accomplished through the planning and construction of their own sustainable facility. It is just over two years since the students and staff of the Landscape Architecture Department first occupied the single-story 20,800 square-foot academic building in January 2003. Two members of a MSU faculty team that participated in making decisions affecting the building’s location, shape, layout, and construction were Pete Melby, a landscape architecture professor, and Tom Cathcart, a biological engineer. The Big Questions The result of careful planning and cooperative efforts focused on creating a facility with conservation as its nucleus is now the subject of scrutiny. Skeptics that question the practicality and promises of sustainable design in a financially-based economy want to measure the results. Are the results positive enough for the project to serve as a model for others? Will the shortand long-term paybacks, or life-cycle costs, be beneficial for the owner of the site and building? As the saying goes, numbers don’t lie. Speaking from his office, Pete Melby states, “This building is using 40-70 percent less energy than the regional average for office buildings.” Last year, the energy costs were about $16,200, compared to an estimate of $27,600 for the same-sized building using Southeastern energy use-rate averages. Melby and Cathcart estimate that use rates for larger adjacent buildings would approach $47,000. One energy cost projection made by the Center for Sustainable Design represents the difference in 30-year energy costs for the facility and for a building having an energy use of 45 kWh/sq.ft. (the average of the other two campus buildings). Based on those figures, a 12,000 square-foot building using current energy saving technologies would save over $600,000 over 30 years if energy costs remained at the current SE average. “This building is proof that new structures can be built without requiring significant energy for heating and cooling. There are compelling reasons to take more control of energy consumption in this nation,” points out Cathcart. “Renewable energy resources will be depleted within 100 years, particularly petroleum and natural gas. That is why we must be forwardlooking.” The building is designed to meet the life support needs for its 250 users. Human life support systems require the provision of food, water, shelter, energy, waste processing, and landscape management in order to sustain life. Specific support systems include an energy efficient shelter design for a Deep South location, water harvesting for irrigation, and treatment of harvested water for drinking, provisions to treat sewage using biological systems, harvesting of wild energy, and thrifty use of energy. Also included are management of the landscape consistent with a site’s natural systems and cycles, and food production. In the Beginning Even though the project is a proven success, its innovation became a twoedged sword in the beginning, prompting both excitement and skepticism as people contemplated its goals. “Initially, of course, there was apprehension when we started this,” reveals Pete Melby, who is also a cofounder and current codirector of Mississippi State’s Center for Sustainable Design, a cooperative project between the Department of Landscape Architecture and the Department of Ag and Bio Engineering. “Nearly everything we suggested at first was suspect. People would say it was not cost effective and the payback would be too long. But, with resources expected to decline and future energy costs expected to soar, we designed this facility to the future.” Built at a cost of $3.5 million, the facility complies with the State of Mississippi mandate that all new state buildings be sustainable. The project manager for this three-acre site, located in the heart of the MSU campus, is landscape architect Ron Hartley, ASLA, of Dale and Associates Architects, P.A. in Jackson, Mississippi. “This is probably the most advanced ecologically-designed project in the state,” claims Hartley, a 1974 MSU graduate. “There was a certain amount of pressure as a graduate of the school and from the Landscape Architecture Department, but it was certainly an exciting project.” Hartley notes that seven members of his firm worked on the project and at least 35 individuals from other businesses served as resources or contractors on the project. Melby says that up to 30 individuals from MSU were routinely involved as well. “The LA Department’s concept called for a diverse building in a unique setting,” explains Hartley. “We utilized a number of consultants and partners. The whole process has resulted in a facility that relates well to the site and is very imaginative. We were able to accommodate virtually everything that was asked of us, including a very unique and different studio setting for the department’s classroom area.” Overall, six regenerative technologies are responsible for making this a sustainable facility: shelter, water, waste processing, energy, landscape management, and food. The shelter technologies deal primarily with materials and design. The objective was to select materials that do not require excessive energy to produce or high transportation costs to get to the point of use. Materials were chosen that do not emit volatile organic compounds. Water Resource and Waste Management In the area of water management, most of the water (about 58 inches per year) that falls on the site is reused on the site. A natural model for filtering and soaking up runoff water is the natural leaf litter layer on the forest and prairie floor. This sponge-like medium cleans the runoff water and stores it for future use. For areas of the site not covered by shelters, paving, or water, filtration of rainfall is carried out by a combination of a thick layer of leaves (detritus layer), native plants in natural plant community arrangements, and plant roots. Drainage from the watershed north of the site flows through a filtration wetland and three pools of water before draining eastward to Catalpa Creek and off the site. Toxic substances from vehicles deposited onto parking lots and roadways need to be filtered and removed before progressing into the natural stream system. A bioswale filters runoff from the asphaltic concrete 19-space parking lot where water is detained for two days for settling and treatment. During heavy rains, only the first flush from the parking lot is detained, and water beyond the first flush drains off the site. Runoff generated by impervious materials is harvested for reuse on the site for drinking and irrigation use. Water that falls on roofs is channeled to the three pools for detention. Runoff stored on the site is slowly released at the same rate that water ran off the site when it was in a wooded and untouched natural state. Water for irrigation is pumped from the pools using solar powered, low-pressure pumps. Irrigation is delivered by waterconserving drip emitters to trees, shrubs, flowers, and vegetables. Some water is collected in 200-1000 gallon (757-3785 L) cisterns, and that stored water is accessed by old-time hand pumps. Water drawn from the second pool is treated for drinking through the use of a series of filters and ultraviolet light treatment. Water is stored in an 80 gal (303 L) pressurized tank that supplies drinking fountains and restroom facilities in the Design Studio and the Gallery/Office facility. The waste processing and sanitary sewage treatment for the facility may be the most interesting and could have been controversial. “We needed to hide our cards on this area until we knew that it could be done,” explains Melby. “We expected that some people would be against it - even before they knew the facts. When we were able to illustrate the entire plan of the facility, with this as a component, it was accepted.” “For instance,” Melby continues, “Other administrators saw that the university was already spending $30,000 a month on sewage treatment and said why not give this a shot and see if sewage could be treated in an inconspicuous and safe manner and eventually begin to lower those costs.” Traditional means of sewage treatment are chemical and energy intensive. Biological treatment methods can save large amounts of energy and chemicals. As a demonstration, liquid sewage effluent from the men’s room in the Office/Gallery facility flows to plant filters in two nearby offices. The combination of urine and water from the men’s restroom flows to the office planters for treatment by microbes. The microbes on the expanded clay gravel media consume nutrients and pathogens suspended in the wastewater. Wastewater is detained for 14 days for maximum treatment before flowing into the outdoor rock reed treatment beds. Plants in the filter planter supply oxygen to anaerobic bacteria in the gravel filter. They also effectively remove airborne microbes through their normal transpiration process, and they add humidity to the air in the office spaces. Sewage from the Design Studio and the Gallery/Offices facility flows first to a septic tank. Solids settle to the bottom of the tank to be decomposed (consumed) by anaerobic bacteria. Liquids flow from the tank to the rock reed treatment beds for a 14-day retention time for thorough treatment. Microbes colonized on the rocks consume nutrients and pathogens within the liquid effluent. Outflow from the rock reed is treated with ultraviolet light for final disinfecting of all living organisms. Treated effluent flows through a subsurface, perforated pipe beneath a shrub bed. Excess water, if there is any, flows to a sump. The rock reed is divided into two lined cells. The first cell is planted with canna lilies and the second cell with warm season experimental plantings. Emphasis is placed on cultivation of plants for the cut-flower market. More common waste management practices such as recycling and composting are also practiced. Landscape management is an important aspect of this facility. As for plant selection, native plants survive in the landscape without major infusions of energy and fertilizers. The site is composed of pools of water with native aquatic plantings, native prairie and meadow plantings, native trees and shrubs, and turf grass for active and intensely used areas of the site. Within the experimental and demonstration gardens, plantings include foliage, flower, and vegetable plants. There are fruit producing trees, shrubs, and vines as well. Grass that requires frequent mowing is limited to intensely used areas. The remainder of the site is thoroughly mulched, replicating the natural condition of the forest floor. The thick, natural covering on the ground shades weed seeds and keeps photosensitive seeds from germinating. The mulch layer holds moisture for best plant growth, and protects the ground from scouring due to raindrop impact and water runoff, which create runnels and channels. Plantings are native in most areas of the site, except around the shelters and in the gardens where non-native plants have been selected due to their outstanding seasonal and fruit producing characteristics. Soils are enhanced through landscape management techniques and monitored for pH levels, soil friability, and soil fertility. Water in the three pools falls 10 feet (3 m) in elevation as water moves through from the upper portion of the site to where it leaves the site. The watershed for the pools extends beyond the pools to the north and south. Runoff from outside the site, but within the watershed, is silt laden due to landscape management practices and requires a sedimentation basin above the upper pool. The basin has the capacity to hold one inch (2.5 cm) of water from rainfall in the watershed. Water velocity is slowed in the basin and water is detained and allowed to drain into the upper pool over a three-day period. Silt that builds up in the sediment basin is periodically removed and used on-site. Oxygen and water fertility levels in the pools are monitored and adjusted as necessary for ideal aquatic plant and animal growth. The facility meets minimum food sustenance requirements. “We will produce one fruit and one vegetable per day per person for five days a week to meet our site food sustainability responsibility,” boasts Melby. Based upon the site user capacity of 250 people, food yields are targeted to provide 2,500 servings per week and 650,000 servings per year. To accomplish this, shrub and tree food production includes apples and pears for fall use. Cabbage, broccoli, Brussels sprouts, leaf lettuce, and mustard greens are produced for fall and spring use. Summer crops include blueberries, okra, squash, and tomatoes. Food grown on the site is either given to site users, or sold at a produce stand. Sustainable Building Design Features When developing the initial design program for the site and facility, it was determined that a series of smaller, linear shelters connected by porches or covered walkways would best accommodate the narrow, linear site. The long sides of the shelters face south and the structures make use of significant insulation in the walls, flooring edges, and in the roofing. The windows can be opened and are equipped with screens, and wide overhangs block summer sun and allow for winter sun heating. Additionally, highly reflective roofing material was used to further improve energy efficiency. Because two-thirds of the yearly heating and cooling bills in the region are for cooling, shelter design focused on reducing the need for cooling. Ceilings in the studios, with a few exceptions, are open 16-24 feet (5-7 m) above the floor, thus allowing warm air to move up to the exposed ceiling. Creating interior spaces with high ceilings where warm air can rise leaves cooler and denser (heavier) air down at the floor and people-use level. The air temperature difference between the floor and ceiling is between 10-15° F (6-10°C). Ceilings in the Office/Gallery facility are 12 feet (3.7 m) high, allowing warm air to rise and collect at the top of the rooms. In winter, temperatures are maintained at a constant 70 degrees and in summer, 70-74 degrees. “With a shelter like this that has a lot of thermal mass, temperatures should be within a 5-to-8-degree range naturally,” Tom Cathcart explained. A state-of-the-art photovoltaic (PV) solar power production facility is located just north of the two-story Design Studio. Silicon based PV cells produce an average of 68 kilowatt-hours of electricity daily, and 25,000 kWh per year. The $300,000 PV 15 kW system is owned and maintained by the Tennessee Valley Authority. Green power from sunlight goes directly into the grid system. An interpretive interactive kiosk is located on the second floor of the Design Studio overlooking the PV array. Wild solar energy is currently being harvested at a rate of 17 kilowatts per day. After the first two years, operating costs are lower than comparable structures and the facility is producing residual environmental benefits while actually producing food. In addition, its energy consumption and negative environmental impact are drastically reduced as compared to typical structures. As a result, this project serves as a shining example of what sustainable design is intended to produce. SLDT