GreenClips.211 03.12.03 EUROPEAN DESIGNERS KEEP POOLS CLEAN WITHOUT CHEMICALS In Germany, Switzerland, Austria and other parts of Europe, there are successful examples of natural swimming pools in every shape and size. A typical natural pool features one body of water with a below-surface wall that divides the pool into two zones -- for swimming and water cleaning. A synthetic, heavy-duty rubber pool liner seals the pool bottom. In the cleaning or regeneration zone, local water and marsh plants are based in a substrate of washed gravel, lime (to buffer pH), loamy sand, and nutrient bond. The swimming area is left without gravel for easy cleaning in the off-season. As a pool's mechanical circulation system pumps water through the regeneration zone, the substrate acts as a natural filter for any small particles in the water. The plants use nutrients from the water as food, which helps prevent algae. Microorganisms and microbes break down pollutants into basic elements. "The main water-cleaning activity takes place in the microorganisms and microbes -- not the water plants," says Rainer Grafinger, with BioNova, a German firm that specializes in natural pools. Although it costs about the same to install a residential natural pool as a traditional one, most owners find that they save on operation costs (there are no chemicals to purchase) and can do the majority of maintenance themselves. Landscape Architecture, Mar 2003, p 34, by Michelle Taute. HOUSING RISES ON TOP OF 25-STORY SLAG HEAP In Pittsburgh, people have begun moving into Summerset at Frick Park, a new luxury housing development built on top of 50 years' worth of steel byproducts. When the project is finished in 10 years, the slag heap -- a 238-acre former industrial area -- will be covered with greenery and 710 houses. The U.S. Environmental Protection Agency says that 500,000 to one million sites around the country could be considered brownfields -- abandoned industrial sites that can be cleaned up adequately to be given a second life. Laws in Michigan, New Jersey, Massachusetts and Pennsylvania guarantee that developers will be released from future liability if they clean up their sites to meet current state standards. The slag underneath Summerset is a fairly benign byproduct of steel making, but digging into it raised concerns in the surrounding communities. The developers agreed to wet down the slag as they worked, to keep down dust carrying things like chromium and manganese. The slag is now covered with 30 inches of soil, grass seed was put down two years ago and trees were planted along the roadways. Other residential brownfield developments under construction include Victoria by the Bay, on the site of a former petroleum refinery in Hercules, California, and Lakeview Bluffs in Painesville, Ohio, on the spot where a former coke and petroleum processing plant once stood. The New York Times, 6 Mar 2003, p D1, by Lynn Ermann. SETTING BENCHMARKS FOR MECHANICAL SYSTEM SUCCESS Architects can design better, more energy-efficient buildings by improving communication with mechanical engineers and working with engineers who are predisposed to innovative design. Some engineering firms talk a good green game, but have a harder time consistently delivering high-performance sustainable designs with comprehensive features rather than one or two favorite techniques. Architects should pay close attention to the engineering firm's design principles, credentials and achievements. And the design team should use quantified metrics that foster resource-efficient design. The following list compares standard practices to suggested mechanical system energy performance benchmarks. Lighting: 1.2 W/sf (standard) vs. 0.8 W/sf installed, 0.4 W/sf operating. Fan Systems: 4 inches of total static pressure drop (standard) vs. 2 inches of total static pressure drop. Chillers: 0.55 kW/ton with no variable speed drive (standard) vs. 0.45 kW/ton with variable speed drive on chiller. Package Units: 8.5 EER (standard) vs. 11 EER (1.1 kW/ton). Cooling Tower: 10 degree approach (standard) vs. 3 degree approach (10 degree approach is the difference between outdoor wet bulb temperature and the cooling tower water supply temperature). Building shell: Tinted single-pane glazing (standard) vs. low-e glazing. Environmental Design and Construction, Mar-Apr 2003, by Chris Lotspeich, Peter Rumsey and Sim Van der Ryn. [Full text: http://www.edcmag.com ] PROCEED WITH CAUTION WHEN IRRIGATING WITH RECLAIMED WATER The single greatest use for reclaimed water is irrigation, both for agriculture and landscapes. The process of treating raw sewage removes every contaminant put into the originally potable water, except for dissolved salts, which are almost impossible to remove. Applying reclaimed irrigation water with an increased dissolved salt content can damage leaves, roots and soil. While techniques to avoid foliar damage and manage rootzone concentration help in the short term, eventually the salt has to go somewhere. In fact, any irrigation water -- no matter what the source: a river, groundwater or reclaimed water -- leaves behind salt in the soil (rainwater, however, is free of dissolved salts). If the salt cannot be drained away, the soil eventually becomes poisoned. Salt accumulation is less of a problem in fast-draining soils than in clays, so it's essential to know the type of soil a project will be built on. Ultimately, drainage is as important as irrigation -- not pushing salt deeper into the soil or into the groundwater but depositing it in the oceans. However, growing legal restrictions, from international treaties brokering riverwater quality to regulations governing stormwater runoff, impede the journey. To create sustainable landscapes and preserve the soil they depend on, these regulatory obstacles must be resolved, and the salt must be sent on to its original destination, the sea. Landscape Architecture, Mar 2003, p 22, by Leah Rottke. GREEN ROOFS TAKE ROOT IN NORTH AMERICA, BUT DESIGN QUESTIONS REMAIN Although modern green roof technology was developed in Germany, today about 10 patented green-roof systems are available from about two dozen companies in North America. The main draw of green roofs is their environmental benefits: they contribute to stormwater management, alleviate the heat island effect, moderate a building's internal temperature, purify outside air, and provide habitats for plants, insects and birds. A green roof keeps water out of a building with several protective layers: waterproof membrane, drainage system, fabric filter, growing medium, and vegetation. Also, layer of insulation may be installed below the membrane, a root barrier may be added above the membrane, a wind barrier may be placed above new plants, and irrigation may be installed. Different green-roofing companies promote different membranes -- from multi-ply modified bitumen to PVC. The plants that seem to fare best are hardy, low-growing succulents. Despite advances in green-roof technology, there are still a lot of design questions, so researchers at North Carolina State University in Raleigh have set up three experimental roofs to investigate the speed at which water runs off both conventional and green roofs, measure how much nitrogen and phosphorus are absorbed by the systems, and determine the optimum roof slope, soil type and thickness, and plant species for the southeast United States. More: http://www.greenroofs.com. Architectural Record, Mar 2003, p 149, by Nancy B. Solomon. . . . . . . . . . . . . . . . . . . . . . . . . . . GreenClips is free of charge thanks to individual members and these sponsors: C&A FLOORCOVERINGS We choose not to just make carpet but to also make a difference. 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