Refinar búsqueda
Resultados 1-10 de 11
Electrochemical removal of Terbuthylazine:Boron-Doped Diamond anode coupled with solid polymer electrolyte
2019
Tasca, Andrea Luca | Puccini, Monica | Clematis, Davide | Panizza, Marco
Terbuthylazine (TBA) has replaced atrazine in many EU countries, becoming one of the most frequently detected pesticides in natural waters. TBA is a compound of emerging concern, due to its persistence, toxicity and proven endocrine disruption activity to wildlife and humans. Techniques applied in water treatment plants remove only partially this herbicide and poor attention is given to the generation and fate of by-products, although some of them have demonstrated an estrogenic activity comparable to atrazine. This paper summarizes the environmental occurrence of TBA and its main metabolite desethylterbuthylazine and reports the performance of an innovative electrochemical cell equipped with a solid polymer electrolyte (SPE) sandwiched between a Ti/RuO₂ cathode and a Boron-Doped Diamond anode, operating at constant current, in the treatment of an aqueous solution of TBA. The herbicide removal in the first 30 min of treatment increases from 42% to 92% as the applied current is increased from 100 to 500 mA. The rate of degradation at 500 mA decreases between 30 and 60 min, with a final abatement of 97%. An 89% removal was reached at 100 mA when the initial TBA concentration was raised from 0.1 to 4 mg L⁻¹ and less than 1% of the herbicide was converted in desethylterbuthylazine and minor metabolites. No chemicals are needed, no sludge is produced. Further research is encouraged, as this technology may be promising for the achievement of a zero-discharge removal of different emerging pollutants as pesticides, pharmaceuticals and personal care products.
Mostrar más [+] Menos [-]Reconditioning of food processing brines
1970
Mercer, Walter A.
Phosphorus removal by ferrous iron and lime
1971
Alvord, E. Thomas
Spent pickle liquor, as a source of ferric ion, was added to primary treatment facilities and found to be effective in removing more than 60% of the phosphorus contained in the sewage. When advanced means for more complete removal of the insolubilized phosphates are available, removals in excess of 90% are indicated. In addition, overall suspended solids removals averaged 61.5% and BOD and COD removals averaged 61.6 and 55.3 percent during a 23 month test period. Required iron dosage ranged from the theoretical minimum of 2.7 to a maximum of approximately 3.1 weights of ferrous iron per weight of phosphorus. The weight increase in sludge solids due to chemical precipitation of phosphorus was 100 lbs/million gallons/mg/liter of phosphorus in the influent. Total costs for treating a raw sewage containing 13 mg/l phosphorus are given.
Mostrar más [+] Menos [-]Pollution abatement and by-product recovery in shellfish and fisheries processing
1971
Peniston, Quintin P. | Braun, F. W. | Johnson, Edwin Lee
Seventy million pounds of seafood wastes, mainly from crab, salmon, and shrimp fishing, containing 22.1 million pounds of COD were discharged to Kodiak Harbor, Alaska in 1970. A private firm was engaged to develop a plan to permit development of beneficial uses for the wastes while concurrently reducing the pollutional load on the harbor. The plan included collection and transportation of the waste to a central processing site on Near Island for by-product recovery. Shellfish wastes would be extracted with dilute alkali to yield a high quality protein and a chitin-calcium carbonate residue, the former to be used as pet food aditives or for industrial applications, and the latter to be exported for conversion to chitin and derived products or used in Alaska as a soil liming and fertilizer material. Fish wastes would also be extracted to yield a concentrated protein product similar to fish solubles oil and bone meal.
Mostrar más [+] Menos [-]Development of phosphate removal processes
1970
Treatment of citrus processing wastes
1970
Goodson, James B. | Smith, Jack J.
Environmental control in the organic and petrochemical industries, 1971
1971
Jones, H. R. (Harold R)
Polymeric materials for treatment and recovery of petrochemical wastes
1971
Klein, Elias | Desai, Shyamkant V. | Smith, James K. | Weaver, Robert E. C.
Phosphorus removal with pickle liquor in an activated sludge plant
1971
Leary, Raymond D.
Hot waste pickle liquor (ferrous sulfate) as an iron source was successful in precipitating phosphorus from solution in a 115 mgd East Plant of Milwaukee's Jones Island Activated Sludge Wastewater Treatment Plant. An 85 mgd section of the plant receiving the same influent was operated as a control. The East Plant with iron addition, achieved 91.3% removals (0.70 mg/1 P effluent residual), while the control West Plant removed 83.1% (1.4 mg/1 P residual). Comparison of efficiencies of purification, pH, alkalinity, and microscopic examinations of the sludge microorganism indicated that the addition of unneutralized waste pickle liquor did not adversely affect purification processes.
Mostrar más [+] Menos [-]