کارایی فرایند الکتروکواگولاسیون در حذف نیترات و فسفات از فاضلاب برکه تثبیت شهر سبزوار با رویکرد پاسخ سطح

نوع مقاله : مقاله پژوهشی

نویسندگان

1 فارغ التحصیل کارشناس ارشد مهندسی منابع طبیعی-محیط زیست، دانشکده جغرافیا و علوم محیطی، دانشگاه حکیم سبزواری، سبزوار، ایران،

2 استادیار، دانشکده جغرافیا و علوم محیطی، دانشگاه حکیم سبزواری، سبزوار، ایران

3 استادیار، گروه محیط زیست، دانشکده جغرافیا و علوم محیطی، دانشگاه حکیم سبزواری، سبزوار، ایران

چکیده

یکی از معضلات زیست محیطی پساب‌ها وجود ریز مغذی‌ها و ماکرو مغذی ها در آن است که مهمترین آن‌ها فسفر و نیترات است. در این مطالعه، حذف فسفات و نیترات از فاضلاب شهری سبزوار با استفاده از فرآیند الکتروکواگولاسیون با الکترودهای آلومینیومی مورد بررسی قرار گرفت. در مطالعه‌ی حاضر، از یک راکتور الکتروکواگولاسیون در مقیاس آزمایشگاهی با حجم تقریبی 1200 میلی‌لیتر مجهز به 3 الکترود از جنس Al در ابعاد 5×12 سانتی‌متر به منظور حذف مورد استفاده قرار گرفت. تأثیر و تداخل پارامترهای بهره‌برداری از قبیل شدت ولتاژ جریان، pH، مقدار FeCl2 و زمان تماس بر حذف فسفات و نیترات توسط نرم افزار Design Expert بررسی شد. اثر پارامترهای pH و FeCl2 در حوضچه های ورودی و اختیاری نیز مورد مطالعه قرار گرفت. هم‌چنین تغییرات pH در روند اکسیداسیون مورد بررسی قرار گرفت. در نهایت می‌توان گفت که فسفات به طور کامل در حوضچه‌های اختیاری و خروجی حذف گردید اما به دلیل غلظت اولیه‌ی پایین فسفات در حوضچه‌ی خروجی، در نهایت با ولتاژ کم‌تر (10 ولت)، زمان ماند پایین‌تر (حدود 3 دقیقه)، مقدار اندک FeCl2 (0/2 گرم بر لیتر) و pH اولیه‌ی محلول در مقایسه با حوضچه‌ی اختیاری حذف کامل فسفات انجام شد. نیترات هم در شرایط بهینه‌ی بهره‌برداری (5/5=pH، اختلاف پتانسیل 25 ولت، زمان 11/50 دقیقه و 0/65=FeCl2 گرم بر لیتر) در حوضچه‌ی خروجی به طور کامل حذف شد. فرآیند الکتروکواگولاسیون با استفاده از ورقه‌های مصرفی آلومینیوم و هم‌چنین سادگی و هزینه‌ی نسبتاً کم آن، کارایی مطلوبی در حذف فسفر و نیترات دارد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigation of Interaction of Effecting Factors in Phosphate and Nitrate Removal from Municipal Wastewater by Electrocoagulation Process with RSM Approach

نویسندگان [English]

  • Susan Khoshsima 1
  • mojtaba hadavifar 2
  • Ghasem zolfaghari 3
1 Department of environment, Hakim Sabzevari University, Sabzevar, Iran
2 Department of environment sciences, Hakim Sabzevari University, Sabzevar, Iran
3 Department of environment, Hakim Sabzevari University, Sabzevar, Iran
چکیده [English]

One of the environmental problems of wastewater is the presence of micro and macronutrients, the most important of which is phosphorus and nitrate. Hence, in this study removal of phosphate and nitrate from aqueous solution was conducted using electrocoagulation (EC) processes with Al electrodes. In the present study, an electrocoagulation reactor was used in a laboratory-scale with a volume of approximately 1200 ml equipped with 3 Al-electrode in a size of 5 × 12 cm2 to remove phosphate and nitrate. The effects of operating parameters such as applied voltage, initial pH of the solution, the value of FeCl2 and reaction times were evaluated. The effect of pH and FeCl2 parameters in inlet and facultative ponds were also studied. Also, pH changes in the oxidation process were investigated. Finally, it can be said that phosphate was completely eliminated in facultative and outflow ponds, but due to the low initial concentration of phosphate in the outlet, less voltage (10 V), less time (about 3 minutes), low FeCl2 dosage (0.2 mg/l) and original pH of the solution were applied compared to the facultative pond., 100 % of nitrate in optimum condition (pH=5.5, applied voltage=25 V, FeCl2=0.65 mg/l, time=11.50 min) in output pond has been removed. In the EC process, the electrocoagulation process using an aluminum electrode, as well as it’s relatively low cost and simplicity, has a good effect on phosphorus and nitrate removal compared to other methods.

کلیدواژه‌ها [English]

  • Phosphate removal
  • Nitrate removal
  • municipal wastewater
  • electrocoagulation
  • Response surface methodology
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