تاثير رژيم آبياري و كاربرد هيدروژل بر گياه پالايي خاك هاي آلوده به مواد نفتي

چكيده انگليسي :

The Effects of Irrigation Regime and Hydrogel Application on Phytoremediation of Petroleum Contaminated Soil Elham Ghaheri e ghaheri@ag iut ac ir March 9 2009 Department of Water Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiJ Abedi Koupai koupai@cc iut ac irS S Eslamian saeid@cc iut ac irAbstractThe industrial revolution of the past century has resulted in significant damage to environmental resourcessuch as air water and soil Petroleum contamination of soil is a serious problem throughout the oil producercountries Total petroleum hydrocarbons TPHs are one of the most common groups of persistent organiccontaminants in the environment and are important sources of soil and environmental pollution in ourcountry especially around oil refineries such as Tehran or Ahvaz oil refinery plant There are many sourcesof TPH contamination in soils including petroleum extraction transportation and consumption Remediation of petroleum contamination of soils is generally a slow and expensive process Phytoremediation is defined as the use of plants to remove contain or render harmless environmentalcontaminants Phytoremediation is a potentially less damaging cost effective but needs longer termmethod for remediation of contaminated land compared to the alternative method such as soil washing incineration or disposal to landfill In this research at the first stage topsoil were collected from the crude oil contaminated area around Ahvaz refinery plant in the south of Iran Ryegrass Lolium perenne plantedin 1 to 2 cm of depth in the pots The plants were irrigated during the growth period so that soil moisturewas kept near field capacity Soil samples were collected at 0 40 50 60 70 80 90 100 110 and 120 daysafter the start of the experiments TPHs was extracted from soil sub samples by Soxhlet using a 1 1 v vdichloromethane and n hexane 150 ml mixture The results of TPH concentration was fitted with zero order kinetic first order kinetic and Higuchi model The result indicated that degradation of TPHs withpresence of plants as a function of time was well fitted with the first order kinetic model The first orderrate constants K and half lives T1 2 for TPHs degradation were 0 0098 1 day and 71 day The results ofphytoremediation showed that there were 65 decreases in TPH concentration with Ryegrass during the 17weeks At the second stage soils were taken from the crude oil contaminated area around Tehran oilrefinery Soils were air dried and passed through a 4 mm sieve The soils were land farmed and were mixedat intervals every 3 days by a garden hoe to ensure a homogenous distribution of the petroleum pollutantsand were irrigated twice a week to maintain moisture Then about 2 kg of soil samples was added to plasticpots with 180 mm diameter and 170 mm height Two grass species Tall Fescue Festuca arundinacea andRyegrass Lolium perenne were selected for phytoremediation and pots were placed in the greenhouse andthe plants were grown for 15 weeks The effect of irrigation regimes was evaluated Therefore treatments ofirrigation were 3 irrigation regimes consisting 50 75 and 100 field capacity FC Leached water wasaccumulated at the bottom of pots and was used for watering to avoid loss of TPH The hydrogel Superabsorb A200 and Zeolite were added to soil samples 6gr kg Each treatment was replicated three times and the experimental layout in the greenhouse was completely randomized At the end of growing trial theplants shoot plus root were harvested washed and dried in an oven at 60 C for 48 h and then weighed Also microbial respiration and TPH concentration in soil samples were determined The results showed thatTall Fescue had higher mean shoot and root biomass than Ryegrass The results indicated the positive effectof using hydrogel and Zeolit on increasing dry biomass of shoot and root There was significant differencein microbial respiration and TPH concentration in soil between vegetated soil and nonvegetated so

قاهري، الهام

تاثير رژيم آبياري و كاربرد هيدروژل بر گياه پالايي خاك هاي آلوده به مواد نفتي

آلودگي نفتي خاك , مواد جاذب رطوبت , زئوليت