فهرست مطالب ali torabiyan

BOD or biochemical oxygen demand is one of the old parameters for organic contamination of wastewater that has over 100 years of oldness. It is important is to the extent that all regulation organizations use it for inspection. BOD has some limitations that defined over the time. COD or Chemical Oxygen Demand introduced and used after BOD but with improvements in technology, replacement of TOC with BOD and COD was proposed. Considering the development of precision instruments in all aspects of life and the widespread deployment of instrumentation in various areas of the environment, decision makers should look for parameters that are rapidly obtainable with modern equipment as the timing of experiments will be ineffective. In addition, a general effort is needed to conduct this kind of research in universities so that the relationships between these parameters can be accurately investigated so that academic centers can be responsive to the needs of industry and society. This review paper wants to find the advantages and disadvantages of these parameters as well as to study the current situation of regulations, inspection, design, operations, control and monitoring of wastewater treatment plants and their future.

Nanotechnology has nowadays found applications in a wide variety of fields including industrial effluent treatment. In this study, iron nanoparticles were synthesized via Ferric choloride reduction using sodium burohydrate to investigate the effects of retention time, nanoparticle concentration, BOD concentration, and pH on the efficiency of BOD removal from wastewater. To determine the optimum contact time, known quantities of the nanoparticles thus prepared were added to wastewater samples of two different concentrations with known values of BOD5 over peirods ranging from 15 to 180 minutes. In a second stage of the study, varying amounts of iron nanoparticles were added in two steps to wastewater samples with a fixed BOD5 concentration and allowed to remain over the optimum contact time to determine the BOD removal efficiency. Subsequently, fixed amounts of iron nanoparticles were added to wastewater samples with varying BOD levels and the BOD removal efficiency was determined. Finally, varying amounts of iron nanoparticles were added to wastewater samples with varing BOD levels over the optimum retention time to investigate the effects of pH variations in each stage on BOD removal efficiency and to determine the optimum pH level. Results indicated an optimum contact time of 45 minutes, an optimum iron nanoparticle content of 3 g for samples with BOD5 concentrations of 35 and 116 mg/l, and an optimum nanoparticle quantity of 5 g for samples with a BOD5 of 289 mg/l. The optimum BOD5 concentration was found to be 289 mg/l and the optimum pH was determined to be 3. At the optimum contact time and at high pollution loads, an acidid pH yields the highest contaminant removal with increasing nanoparticle additions.