Iranian Journal of

Backgrounds and Objectives: Formaldehyde and phenol are key precursors in the industrial manufacture of resins. Toxicity of these compounds prevents function of microbial populations, so they affect the biological treatments. The aim of this study was investigation of TOC removal from phenol-formaldehyde resin manufacturing wastewater by electrocoagulation using Al- electrodes.
Materials and Methods: This study is the laboratory scale experiment was conducted as a pilot. Wastewater sample was adjusted in the desired pH, electrical conductivity and current density, then it was placed in to the reactor contains four electrodes in aluminum. The electrodes were connected to a DC power supply (0-40V, 0-3A). Samples were collected for TOC determination in the middle of cell at regular time intervals. Collected samples were analyzed using TOC analyzer.
Results:The results indicated that the optimum conditions for the removal of TOC were current density 75 A/m2, solution pH 4 and Conductivity 3 mS/cm. In this condition energy consumption was found 22.5 kWh m-3 after 60 min reaction.
Conclusion: This study shows that electrocoagulation of wastewater from phenol-formaldehyde resin manufacturing can be used as a pretreatment process.

Background and Objectives: Soil polluted with total petroleum hydrocarbon (TPHs) is a great threat to human health. Phytoremediation, the use of vegetation for treatment of contaminated soils, is an attractive and cost-effective alternative to reduce pollutant from soil. This paper evaluates the effects of the plant and nutrients on the removal of TPHs from soil. Material and methods: Soils were collected at depth of 0-30 cm, and then polluted with 1 and 2.5 % w/w of crude oil. After preparing the experimental pots, Rhizosphere microbial number, plant biomass, and residual TPHs were determined. TPHs and heterotrophic bacterial number were measured by GC and HPC method respectively. Data were analyzed using the Statistical Package for Social Sciences (SPSS 17 for Windows) software and Excel. Results: It was found that the average percent of TPH removal in planted soil (28.42%) was higher than that in unplanted soil (12.2%) (p<0.05). Moreover, the average percent of TPH removal in treatments received nutrient and free nutrient treatments was 35.5and 17.7% respectively. Conclusion: Generally compared with the other studies, high clay and salinity of the experimental soil had a negative effect on phytoremediation efficiency. Finally, regarding to the high clay and salinity of the experimental soil, the phytoremediation efficiency was relatively desirable.