کاهش BOD5 از آب‌های‌آلوده با استفاده از گیاه وتیور در تالاب‌مصنوعی جریان‌سطحی
محورهای موضوعی : مدیریت آب در مزرعه با هدف بهبود شاخص های مدیریتی آبیاری
1 - استادیار دانشگاه آزاداسلامی، واحد شوشتر، گروه علوم آب، شوشتر، ایران
کلید واژه: وتیور, کاهش BOD5, تالاب مصنوعی,
چکیده مقاله :
در تالاب‌های مصنوعی از نوع جریان سطحی، حجم گسترده میکروارگانیزم‌های اطراف ریشه گیاه، محیط مناسبی برای تصفیه فاضلاب فراهم می‌نمایند. به‌منظور بررسی اثر گیاه وتیور و زمان ماند فاضلاب، در کارآیی تصفیه این نوع سامانه‌ها، نه حوضچه در شرکت کشت و صنعت نیشکر کارون واقع در شهرستان شوشتر ساخته‌شد. واحدها، به‌صورت موازی در کنارهم قرارگرفته و طول هر واحد 3 متر، عرض 1 متر و ارتفاع 8/0 متر بود. جریان پیوسته فاضلاب کشاورزی حاصل از شستشوی نی، از اواسط آذرماه 1392 تا خردادماه سال 1393 برقرار شد. سه سامانه، با کشت ریشه گیاه درخاک (S)، سه سامانه با کشت گیاه روی صفحات شناور (F) و سه سامانه بدون گیاه و بستر متخلل به عنوان شاهد (C) در نظر گرفته شدند. متوسط غلظت BOD5 فاضلاب ورودی به هر واحد 69/15±115 میلی‌گرم بر لیتر و زمان‌های ماند مورد آزمایش 3، 5 و 7 روز بودند. در طی دوره آزمایش، غلظت BOD5 ورودی و خروجی هر واحد، اندازه‌گیری و با استفاده از نرم‌افزار آماری SAS آنالیز شد. نتایج حاصل از آنالیز نشان داد، اختلاف معنی‌داری بین سامانه‌های حاوی گیاه و فاقد گیاه (شاهد) در زمان‌های ماند وجود دارد. سامانه حاوی گیاه و زمان ماند 7 روز در ماه خرداد، دارای بیش‌ترین مقدار بازده حذف، با میانگین 48/68 درصد بود. به‌عبارت دیگر، شرایط بهینه برای حصول حداکثر بازده حذف BOD5 از فاضلاب کشت و صنعت نیشکر کارون، در سامانه تالاب مصنوعی شناور با کشت گیاه وتیور و در زمان ماند 7 روز به‌دست آمد.
In the free water surface flow (FW-SF) constructed wetlands, a large number of micro organisms that live around the roots of plants create a suitable environment for wastewater treatment. To study the effect of Vetiver plant and sewage retention time in treatment efficiency of such systems, nine ponds in the Karoun sugarcane Agro-industrial located in the city of Shushtar was built. Units, in parallel with each other and each unit with length 3m, width 1m and height 0.8 meters. Continuously, agricultural wastewater from the washing process of sugarcane from December 2013 until May 2014 was established. Three of the units filled with soil and were transplanted with vetiver (S), three units were cultivated with vetiver on the floating platform (F) and three units were kept unplanted as control (C). The average BOD5 concentration of the wastewater entering the unit was 115±15.69 mg/l and retention times of experiments were 3, 5 and 7 days. During the experiment, the concentration of BOD5 per unit of input and output measurements was analyzed using SAS software. The results of the analysis showed significant differences between plant and non-plant systems, including retention times. The constructed wetland system with plant cultivated and the retention time of 7 days in May had highest value of the average removal rate equal to 68.48 percent. In other words, optimum conditions for maximum BOD5 removal rate of Karoun sugarcane Agro-industrial wastewater in floating constructed wetlands systems was with vetiver cultivated and in the retention time of 7 days.
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