Process treats waste water, produces algae Waste water treatment, renovation of water for recycling, and protein production-all at the same time with one treatment process. That's the promise held out for the advanced photosynthetic system (APS) following a year's work with the process in a pilot plant at Hebrew University of Jerusalem, Israel. The work was carried out under an R&D contract from Ecology Development Corp., Washington, D.C. Dr. Gedalyahu Shelef, head of the project in Jerusalem, explains that the particular benefit for which a commercial plant would be optimized depends on the location. Water renovation for recycle might be the primary aim for a plant in a water-short area such as the southwestern U.S. Food-short areas might be primarily interested in protein production for animal feed. Results of the pilot plant work have been promising enough, according to EDC board chairman Stanley Z. Siegel, that E D C expects to have a marketable, fully engineered waste water treatment plant for medium and small communities ready by the summer of 1971. The company hopes to install a full-scale demonstration plant in the U.S. or Puerto Rico. Grow algae. The APS process, Dr. Shelef explains, is an intensified form of the high-rate algal pond system originally developed by Dr. William Oswald of the University of California, Berkeley. Basically, it involves growing algae at the same time that the water is undergoing activated sludge treatment. In tests at the Jerusalem pilot plant, the process has been able to remove about 907c of biochemical oxygen demand (BOD) and chemical oxygen demand ( C O D ) , Dr. Shelef says. At the same time it removes about 807c of total nitrogen and about 507c of dissolved phosphorus. The pilot plant operates on part of the Jerusalem sewage system equivalent to a system for about 1000 persons. The stream, Dr. Shelef says, has a high BOD loading. Further development, Dr. Shelef believes, will lead to even higher removal performance. At present, filtration is used to remove algae. The developed process will use lime treatment, however. Lime precipitates the algae, which can then be collected by precipitation, filtration, or flotation. Dr. Shelef figures flotation will be best, since there is a natural degree of flotation resulting from agitation caused by reaction of the lime with oxygen in the water. Meanwhile, since a retention period of some 48 hours is required, the sludge precipitates and,
Scientists sample water at Jerusalem treatment pilot plant
under the advanced aeration used, selfdigests. The Jerusalem pilot plant covers an area of 3000 sq. ft. and has a treatment capacity of 15,000 gallons per day. The area requirement, Dr. Shelef says, is only one fifth that of conventional oxidation ponds. EDC considers the process not only in terms of waste water treatment but also as a source of water through renovation and recycle. The algae are
absorbent, so that product water contains less refractory (taste and odor causing) substances than with most tertiary treatment processes, Mr. Siegel says. Thus a final treatment with activated carbon should provide water pure enough for recycle. As for protein value, Dr. Shelef points out that bioassay work carried out at the University of California shows that algae have a nutritional value in animal feed better than that of soybean meal.
A New Dimethyl Ester
Dimethyl Succinate I am interested in evaluating dimethyl succinate for one of these application areas, Q surface active agents Q plasticizers Qchemicalintermediate •
solvent • other
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NAME COMPANY
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STREET CITY
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ZIP
EL PASO PRODUCTS COMPANY Box 3986, Odessa; Texas 79760 "Processing the past into your future"
AUG. 3, 1970 C&EN 47
