ISSN:0278-4491    

DOI:10.1002/ep.670110402

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670110403

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670110405

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670110406

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670110408

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

ISSN:0278-4491    

DOI:10.1002/ep.670110409

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

摘要:

AbstractFree as well as organically‐bound cyanides in a waste stream have been destroyed by alkaline hydrolysis in a simple pipeline reactor. This process has been running successfully at plant scale since 1969. Kinetic analysis shows that the hydrolysis is (pseudo) first order, but with two activation energies depending on temperature: 15.5 and 10.5 kcal/gm mole, for temperatures below and above 170°C, respectively. At lower temperatures (below 170°C), the rate limiting step is destruction of free and loosely bound cyanide, and at higher temperatures, the rate limitation is cyanide release from the more resistant organic entities. Design of plant scale reactors, based on laboratory kinetic data, requires estimation of the extent of backmixing. This has been estimated successfully using literature reported values of axial diffusion coefficients for various geometries considered. Plant performance data have been found to correlate very close to the design estimates.The pipeline hydrolysis reactor offers a novel and simple solution and should be applicable to cyanide disposal problems in a number of industr

ISSN:0278-4491    

DOI:10.1002/ep.670110410

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

摘要:

AbstractThe remediation of lead contaminated soil at Superfund sites and urban soil is a serious concern, given the grave effects of lead exposure and the prevasive nature of the threat. The lead species of interest are elemental lead, lead sulfate, basic carbonate of lead and lead dioxide. This paper describes work done to solubilize these species and recover the contaminants as salable lead sulfate. Proof of concept was done using the pure chemicals. After this, bench scale experiments were done using a soil that was dosed with varying amounts of the contaminants (total lead from 1,000 to 10,000 ppm) and better than 80% of the contaminants was recovered as lead sulfate. The treated soil passed the TCLP test with 3.0 ppm lead, showing that it could be be redeposited on site. A pilot‐plant scale‐up is being explo

ISSN:0278-4491    

DOI:10.1002/ep.670110411

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

摘要:

AbstractHydrogen peroxide (H2O2), is known in the food processing industry to reduce COD, BOD, to prevent anaerobic conditions in pipes, tanks and lagoons and to remove malodorous sulfides in effluents from anaerobic wastewater treatment. It has recently been shown to also provide effective solids removal from food processing wastewater. The wastewater of food processing plants often contains a very high loading of organic material consisting of fat, oil and grease (FOG), resulting in unacceptable BOD and COD levels. Since many wastewater treatment systems are being pushed to the limit of their capacity or are already overloaded, the high FOG loading cannot be removed well by the conventional means of treating the wastewater with dissolved air flotation or grease traps. As a result, many food processors are paying surcharges for not being in compliance with the tight discharge limits. To overcome these problems, a process has been developed using H2O2for enhanced FOG recovery and BOD removal. The process is based on the formation of microbubles which attach themselves to the FOG particles and float them to the surface where they can be easily skimmed off. In addition to meeting effluent standards, the process has been able to yield a material that is very renderable and suitable for reuse. Technical and operational data of several industrial applications in the U.S. and Canada are presented, together with process costs. H2O2treatment will generally be most applicable when improvement of solids removal is required without major investment costs, e.g. emergency situations, during seasonal peaks or increased production.

ISSN:0278-4491    

DOI:10.1002/ep.670110412

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY

摘要:

AbstractBiological slurry reactors were tested for removal of polynuclear aromatic hydrocarbons (PAHs) from creosote contaminated soil. Five bioslurry reactors, operated in parallel, kept the soil aerated, partially suspended and well mixed.The reactors were inoculated with indigenous microbes of the Genus Pseudomonas. Nutrients were added to maintain the optimum ratio of carbon, nitrogen, and phosphorus. Temperature within the reactors was approximately 25°C. The slurry consisted of approximately 30% contaminated soil.Results of pilot studies showed that approximately 90% of the total PAHs were removed in the first two weeks. Total PAH concentration in the soil was reduced from approximately 10,973 mg/kg to 1,097 mg/kg. Two and three ring PAHs, such as naphthalene, fluorene, and phenanthrene were approximately 96% removed in the first two weeks and higher ring compounds such as chrysene, benzo‐a‐pyrene, and benzo(b) fluoranthene were approximately 83% removed in the first two w

ISSN:0278-4491    

DOI:10.1002/ep.670110413

出版商:American Institute of Chemical Engineers    

年代:1992

数据来源: WILEY