بررسي عملكرد فيلتر مستغرق باهواده در حذف آترازين

Performance of Submerged Aerated Biofilter for Atrazine Removal from Aquatic Environment

با كمبود زمين‌هاي زراعي و از بين رفتن محصولات به وسيله‌ي آفات استفاده از آفت‌كش‌هايي مانند آترازين افزايش يافته است. اين علف‌كش به دليل فشار بخار كم، نيمه عمر بالا و تحرك زياد منجر به آلودگي اكوسيستم‌هاي گوناگون شده است. روش‌هاي فيزيكي و شيميايي بسياري براي حذف اين علف‌كش از محيط‌هاي آبي و خاكي پيشنهاد شده، اما اين روش‌ها داراي هزينه‌هاي بسيار و همراه با توليد محصولات جانبي سمي ديگري است. روش‌هاي بيولوژيكي به دليل داشتن سيستم آنزيمي قادر به معدني سازي كامل و استفاده از اين علف‌كش به عنوان منبع كربن، نيتروژن و انرژي مي‌باشند و از طرفي فيلترهاي مستغرق باهواده به سبب ماهيت روش تصفيه‌شان كمك شايان توجهي در پايين آوردن هزينه‌ها نموده‌اند. به همين دليل در مطالعه‌ي حاضر توانايي فيلتر بيولوژيكي مستغرق باهواده براي تجزيه آترازين از محيط‌هاي آبي در 4 سطح غلظت و 3 سطح زمان ماند هيدروليكي مورد ارزيابي قرار گرفته است. نتايج نشان دادند كه بيشينه راندمان حذف آترازين و ميزان اكسيژن مورد نياز شيميايي محلول به ترتيب برابر9/97 و 3/98 درصد بود. همچنين نتايج حاكي از اين مطلب بودند كه مدل استور-كينكنن بر بارگذاري اين بيوفيلتر با آترازين برازش بسيار خوبي دارد (99/0 > R2). مي‌توان دريافت كه فيلتر مستغرق باهواده كارآيي بسيار خوبي در حذف مواد آلي و مواد سمي پايدار از خود نشان مي‌دهد و تجزيه آترازين در فرآيند كومتابوليسم بسيار موفقيت آميز بوده و اينگونه استنباط شد كه جمعيت ميكروبي هوازي در تصفيه محيط‌هاي آبي آلوده به آترازين موثر است.

With rapid increasing of population and thereby enhancing demand for food and lack of arable land for agriculture activities, as well as destruction of a major part of crops by pests, especially weeds, use of herbicides such as Atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine) increased highly. Atrazine is a member of s-triazine group herbicides and is a probable human carcinogen (Group 2B). Atrazine is resistant in the environment and, as a result, causes serious environmental problems. Moreover, it penetrates through the surface and subsurface water bodies as well as groundwater due to its excessive usage and high persistence and mobility. In general, several mechanisms, such as oxidation-reduction, photolysis, hydrolysis, adsorption, incineration, dehalogenation, reverse osmosis, and Advanced Oxidation Processes (AOP), are available for removing Atrazine from contaminated water and wastewater; however, these mechanisms are very costly, have many performance problems, produce a lot of toxic intermediates which are very harmful and dangerous, and cannot completely mineralize Atrazine. Biodegradation is an economically viable technology which leads to complete degradation and mineralization of Atrazine and produce simple compounds, such as carbon dioxide, water, nitrogen, and organic materials. Submerged aerated filters to their treatment mechanism greatly contributed to reduce treatment cost .In this study potential of Biological Aerated Filter (BAF) in Atrazine removal from aquatic environment, at 4 concentration of Atrazine and 3 hydraulic retention times (HRTs) was evaluated. Based on the results Atrazine degradation potential of the mixed aerobic consortium was evaluated under various Atrazine concentrations and HRTs. It was shown that maximum efficiency in Atrazine and Soluble Chemical Oxygen Demand (SCOD) removal was 97.9% and 98.3%, respectively. Modeling aims to simulate or optimize a process in physical, chemical, or biological environments. In case the obtained model has desirable fitness, it will be of great help in producing the data and predicting the unknown conditions. Modeling represents a summary of the facts. Origin of modeling is achievement the best possible solution with the lowest cost. Modeling can show the ultimate impact and consequences of the absence of other species that can be occurred in a series of reactions. Scientists have interest in modeling of these reactors in recently years, that there are various theories about them. By using this theory, we can predict the behavior of these reactors. Because in this study behavior of the reactor was modeled on removal Atrazine. The results of this study showed that stover-kincannon models have very good fitness (R2 > 99%) in loading Atrazine in this biofilter