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June 1997 An Economically and Environmentally Sustainable Phosphorus Removal Engine By Kyle Jensen Attached algae, termed Periphyton by scientists, grows faster than any plant community on Earth. This may not seem very notable or important until you grasp how little food periphyton takes to achieve this tremendous growth rate. Periphyton forms an important part of the food chain in many water systems. They developed millions of years ago in water systems where food was scarce. Periphyton can find food when it is present in 10-20 parts per billion and lower. This is analogous to eating a quart of ice cream spread over Interstate 95 from Jacksonville to Miami! No wonder algae is the first thing to overpopulate waters receiving nutrient laden runoff. We can now use the abilities of periphyton to clean our runoff from farm, industrial and urban areas through a process called Periphyton Filtration. Periphyton Filtration is essentially farming algae and in this light it is easy to understand that once the nutrients and other pollutants have "eaten" or assimilated the nutrients, they can be removed from the water stream by harvesting. Managed periphyton or Periphyton Filtration (TM) is a term describing an artificial culture surface, which is harvested on a 7 to 14 day interval or longer under certain conditions. This culture system is specifically designed to allow efficient harvesting of the algae. Optimized culture systems for periphyton have been designed and built using recycled materials with a focus on simplicity and economical construction. While some systems are utilitarian others are meticulously designed and ornately crafted into peaceful shore side water gardens. Harvesting of the microalgae is analogous to mowing a lawn in that the roots are left behind and quickly regrow. The harvested algae have consumed the nitrogen, phosphorus and other contaminants and are removed from the water system. Superintendent of the Everglades National Park, Dr. Richard Ring said "We need to go beyond removing pollutants such as phosphorus in the Everglades, we need to be thinking about the ultimate fate of the pollutants. What do we do with them once we get them out of the water?" Periphyton Filtration actually exports nutrients and pollutants from a water system unlike other systems which sequester them within the water shed. Periphyton is widely known to remove many elements and compounds from water and they can be exported from the basin when harvested. Carbon is a prime nutrient and uptake by the periphyton causes temporary pH rise over long culture surfaces inducing enhanced precipitation of a wide range of metals and degradation of some pesticides and other xenobiotics (herbicides and pesticides etc.). Nitrogen and phosphorus are also primary nutrients and can be stripped to very low ranges. Concentrations are very low in the periphyton but the quantity of periphyton is large. Periphyton Water Gardens are shore side filters for urban lakes and ponds. One is currently being built in Orlando Florida, sponsored by the St. Johns River Water management District and The City of Orlando. Periphyton Water Gardens incorporate aesthetically coordinated design elements, which appeal to the human desires for place making. Periphyton culture surfaces are artistically deployed in a park like setting amongst sculpture, a sundial, and other art with a philosophical and scientific organization. Educationally descriptive plaques round out a facility, which has a lake oriented natural remediation function, as well as social and educational benefits. Floway Systems are large-scale utilitarian facilities for mass removal from very large flows. Floways are sloped culture surfaces roughly 10-50 times longer than wide. Curbs at the long sides provide for a deployable harvester to service the culture surface. Floways are designed to be constructed on virtually any consistent low moisture soil. Phosphorus removal correlated to large scale ranged 380-800 Kg/ha/yr. in lake systems and up to 1800 Kg/ha/yr. (1628 lbs./acre/yr.) in tertiary waste water systems. This is 100 to 1,000 times greater yield than wetland systems with a totally natural process using plants already in the water system. Periphyton Filters are most economically designed to operate with an associated basin to even out storm surges. Systems can be oversized to handle storm surges and operate off lake water in between storm events. Simulated hydrologic modeling was studied with the SFWMD 10-year historic data set. Flows for EAA basins 6,7 and 8 were used to select the most optimal match of retention basin and treatment area for inflow outflow reduction from 200 PPB to 50 PPB. 900 acres of treatment area and 12,000-acre wetland storage completely treated all but 10% of storm flows. Estimates for this Periphyton Culture Area are under $200 million. The system would require $1.8 million per year to harvest on a 7-day interval with 30 harvesters and provide 200 skilled jobs. This is higher treatment at a fraction of the land area and cost of the planed wetlands. Many technologies including Periphyton can clean water for sure but sustainability goes beyond that. Sustainability means we can do it forever with no byproducts or sludge. Periphyton Filtration can pay its own way without generating byproducts. In fact the process consumes other byproducts and this is the key to true sustainability. We looked to our society, it's needs, desires, natural characteristics and economical strategies in the quest for true sustainability and found a simple methodology that wins on all accounts. A process was developed that combines the wet harvested algae with dry shredded recycled newsprint or paperboard. The algae newsprint pulp has demonstrated superior characteristics for molding into many packaging products in prototype trials. The favorite is a loose fill or packing peanut to replace the polystyrene ones which are so hard to control and dispose of. The algal/newsprint peanut is shaped like the letter E and will be marketed under the trade name"E-Pieces" (TM). We all have used molded pulp products, such as the 4-drink holder at fast food restaurants, egg cartons, corner protectors and many other products. The social evolution of marketing and mail order have created the need to ship products and this packing out of the water basin where the nutrient pollution was taken from. With them the nutrients are removed and most importantly when the packing has served its purpose the "E-Pieces" don't go to the land fill, they are dumped into ones garden or house plants where the nutrients enrich the soil and enhance the tilth and moisture carrying capacity. Based on the current sales in the loose fill industry "E-Pieces" can make a healthy profit which can cover both the cost to harvest the periphyton, providing jobs, with enough left over to completely pay off the cost of the Periphyton Filtration System through a municipal bond. This is "Sustainability by Nature", an economically viable method to improve our environment on multiple levels with out the burden of taxes. Kyle Jensen is a Project Manager at SAIC. For more information, contact him at 407/843-3655 or e-mail:ALGAEKYLEJ@AOL.COM |