Sequential treatment of organics and heavy metal ions wastewater, comprises initializing fenton process by adding ferrous salt and hydrogen peroxide into continuously mixing wastewater, and adding iron salt to re-adjust molar ratio

摘要

Sequential treatment of organics and heavy metal ions wastewater, comprises initializing fenton process by adding ferrous salt and hydrogen peroxide into continuously mixing wastewater to adjust molar ratio of organics:hydrogen peroxide:ferrous ions in proper molar ratio; and adding iron salt to re-adjust the molar ratio of organics:hydrogen peroxide:ferrous ions to control a molar ratio of ferrous ions:heavy metal ions greater than 4. Sequential treatment of organics and heavy metal ions wastewater, comprises: (1) initializing a fenton process by adding proper amount of ferrous (Fe) salt and hydrogen peroxide (H 2O2) into continuously mixing wastewater to adjust a molar ratio of organics:H 2O 2:ferrous ions (Fe 2 +)) in proper molar ratio, where reactive environment is controlled under 20-100[deg]C and pH of 2-5, and where a mixing rate is adjusted properly, and then monitoring variance of pH and oxidation-reduction potential (ORP) during the fenton process in determining the terminal time of the fenton process as pH and ORP both reach a steady state; (2) adding proper amount of Fe salt to re-adjust the molar ratio of organics:H 2O 2:Fe 2 + to control a molar ratio of Fe 2 +:heavy metal ions greater than 4; (3) heating to 20-100[deg]C, and adding proper amount of Fe salt and alkali to adjust pH ranging from 8 to 12 for conducting a concentration for heavy metal ions; (4) sequentially aerating air with a proper aerating rate to initialize a ferrite process, and then monitoring variance of pH and ORP during the ferrite process in determining the terminal time of the ferrite process as pH and ORP both reach a steady state, by which ferrite products are capable of being formed; (5) delivering slurry out of an outlet of a reactor tank and into a sedimentation tank for solid/liquid separation and filtration, by which solid sediment of the ferrite products may be further examined with a toxicity characteristic leaching procedure (TCLP), and filtrate that is filtered and separated from the slurry may be recirculated to the step (3) for reuse or directly drained away after an aqueous analysis and a pH adjustment. The above steps may sequentially treat the organics and the heavy metal ions contained the mixed wastewater by using the fenton process to reduce the effect of the organics on the magnetism of the ferrite products so as to enhance the quality of the ferrite products. Fe ions taken as catalysts in the fenton process may be turned into a reactant in the recyclable ferrite process to solve a color problem of the wastewater caused by ferric ion (Fe 3 +) and reduce iron sludge caused by coagulation after the fenton process.