بررسي كارايي سيستم هاي طبيعي و لجن فعال جهت تصفيه فاضلاب شهري

A Survey on Efficiency of Natural Wastewater Treatment Systems and Activated Sludge for Municipal Wastewater Treatment

ﭼﮑﯿﺪه زﻣﯿﻨﻪ و ﻫﺪف: ورود ﻣﻮاد آﻟﯽ ﺑﻪ ﻣﻨﺎﺑﻊ آب ﺳﺒﺐ ﻣﺼﺮف اﮐﺴﯿﮋن ﻣﺤﻠﻮل ﺷﺪه و ﺑﺮاي ﻣﻮﺟﻮدات زﯾﺴﺘﯽ ﻧﺎﻣﻄﻠﻮب ﺗﻠﻘﯽ ﻣﯽﺷﻮد. ﻟﺬا ﻫﺪف از اﯾﻦ ﺗﺤﻘﯿﻖ، ﺑﺮرﺳﯽ ﮐﺎراﯾﯽ ﺳﯿﺴﺘﻢ ﻫﺎي ﻃﺒﯿﻌﯽ ﺗﺼﻔﯿﻪ ﻓﺎﺿﻼب و ﻟﺠﻦ ﻓﻌﺎل ﺟﻬﺖ ﺗﺼﻔﯿﻪ ﻓﺎﺿﻼب ﺷﻬﺮي ﺑﻮد. روش ﺑﺮرﺳﯽ: ﭘﮋوﻫﺶ ﺣﺎﺿﺮ ﺑﻪ روش ﺗﻮﺻﯿﻔﯽ ﻣﻘﻄﻌﯽ ﺑﺮ روي ﺗﺼﻔﯿﻪﺧﺎﻧﻪﻫﺎي ﻓﺎﺿﻼب اﺳﺘﺎن ﮐﺮﻣﺎﻧﺸﺎه در ﻃﻮل ﻣﺪت ﯾﮏﺳﺎل اﻧﺠﺎم ﭘﺬﯾﺮﻓﺖ. در ﻃﻮل ﻣﺪت ﺗﺤﻘﯿﻖ ﻫﺮ ﻫﻔﺘﻪ ﻧﻤﻮﻧﻪﺑﺮداري از ﻓﺎﺿﻼب ورودي و ﭘﺴﺎب ﺧﺮوﺟﯽ از ﺗﺼﻔﯿﻪ ﺧﺎﻧﻪ اﻧﺠﺎم ﺷﺪ و ﮐﺎراﯾﯽ ﺗﺼﻔﯿﻪ ﺧﺎﻧﻪ ﺑﺎ ﺳﻨﺠﺶ ﭘﺎراﻣﺘﺮﻫﺎﯾﯽ ﻧﻈﯿﺮ BOD5 ،TSS و COD ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺖ. ﺗﻤﺎﻣﯽ ﻣﺮاﺣﻞ ﻧﻤﻮﻧﻪﺑﺮداري و اﻧﺠﺎم آزﻣﺎﯾﺶﻫﺎ ﺑﺮ اﺳﺎس روشﻫﺎي ﻣﻮﺟﻮد در اﺳﺘﺎﻧﺪارد ﻣﺘﺪ اﻧﺠﺎم ﺷﺪ. ﯾﺎﻓﺘﻪ ﻫﺎ: ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﻣﯿﺎﻧﮕﯿﻦ ﮐﻞ ﺑﺮاي ﭘﺎراﻣﺘﺮ BOD5 ﭘﺴﺎب ﺧﺮوﺟﯽ در ﺳﯿﺴﺘﻢﻫﺎي ﻣﺨﺘﻠﻒ ﻧﯿﺰار ﻣﺼﻨﻮﻋﯽ، ﺑﺮﮐﻪ ﺗﺜﺒﯿﺖ، ﻫﻮادﻫﯽ ﮔﺴﺘﺮده و ﻟﺠﻦ ﻓﻌﺎل ﻣﺘﻌﺎرف ﺑﻪﺗﺮﺗﯿﺐmg/l 21 ،25 ،55 و 23، ﺑﺮاي COD ﺑﻪﺗﺮﺗﯿﺐmg/l 40 ،43 ،143 و 40 و ﺑﺮاي TSS ﺑﻪﺗﺮﺗﯿﺐmg/l 40 ،101 ،47 و 33 ﺑﻪ دﺳﺖ آﻣﺪ. از ﺑﯿﻦ ﺳﯿﺴﺘﻢ ﻫﺎي ﻣﻮرد ﺑﺮرﺳﯽ ﺑﯿﺶ ﺗﺮﯾﻦ ﻣﯿﺰان ﺣﺬف COD ﻣﺮﺑﻮط ﺑﻪ ﺳﯿﺴﺘﻢ ﻟﺠﻦ ﻓﻌﺎل ﻣﺘﻌﺎرف)%86/97( و ﮐﻢ ﺗﺮﯾﻦ آن ﻣﺮﺑﻮط ﺑﻪ ﻧﯿﺰار ﻣﺼﻨﻮﻋﯽ)%61/6( ﺑﻮده و ﺑﺎﻻﺗﺮﯾﻦ ﻣﯿﺰان ﺣﺬفBOD5 ﻣﺮﺑﻮط ﺑﻪ ﺳﯿﺴﺘﻢ ﺑﺮﮐﻪ ﺗﺜﺒﯿﺖ)%85/18( و ﭘﺎﯾﯿﻦ ﺗﺮﯾﻦ آن ﻣﺮﺑﻮط ﺑﻪ ﻧﯿﺰار ﻣﺼﻨﻮﻋﯽ)%72/01( ﻣﯽ ﺑﺎﺷﺪ. ﻧﺴﺒﺖ BOD5/COD در ﻓﺎﺿﻼب ورودي ﺑﺮاي ﺳﯿﺴﺘﻢﻫﺎي ﻣﻮرد ﺑﺮرﺳﯽ ﺑﻪ ﺗﺮﺗﯿﺐ 0/59 ،0/62 ،0/56 و 0/55 ﺑﻪ دﺳﺖ آﻣﺪ. ﺑﺤﺚ و ﻧﺘﯿﺠﻪ ﮔﯿﺮي: در ﺑﺮرﺳﯽ اﻧﻄﺒﺎق ﮐﯿﻔﯿﺖ ﭘﺴﺎب ﺧﺮوﺟﯽ از ﺗﺼﻔﯿﻪ ﺧﺎﻧﻪﻫﺎي اﺳﺘﺎن ﮐﺮﻣﺎﻧﺸﺎه ﺑﺎ اﺳﺘﺎﻧﺪاردﻫﺎي ﺳﺎزﻣﺎن ﺣﻔﺎﻇﺖ ﻣﺤﯿﻂ زﯾﺴﺖ اﯾﺮان ﻣﯽ ﺗﻮان ﻧﺘﯿﺠﻪ ﮔﺮﻓﺖ ﮐﻪ ﭘﺴﺎب ﺗﻮﻟﯿﺪي از ﻧﻈﺮ ﭘﺎراﻣﺘﺮﻫﺎي ﻣﻮرد ﺑﺮرﺳﯽ ﺑﺎ اﺳﺘﺎﻧﺪاردﻫﺎي راﯾﺞ ﻣﻄﺎﺑﻘﺖ داﺷﺘﻪ اﺳﺖ و ﻣﯽ ﺗﻮان از آن اﺳﺘﻔﺎده ﻣﺠﺪد ﻧﻤﻮد و ﯾﺎ ﺑﻪ آب ﻫﺎي ﭘﺬﯾﺮﻧﺪه ﺗﺨﻠﯿﻪ ﮐﺮد. ﻫﻢ ﭼﻨﯿﻦ ﮐﺎراﯾﯽ ﺳﯿﺴﺘﻢ ﻫﺎي ﻃﺒﯿﻌﯽ در ﺣﺬف ﭘﺎراﻣﺘﺮﻫﺎي ﻣﻮرد ﺑﺮرﺳﯽ ﺑﯿﺶ ﺗﺮ از ﺳﯿﺴﺘﻢ ﻫﺎي ﻟﺠﻦ ﻓﻌﺎل ﺑﻮد.

Background and Objective: Consumption of dissolved oxygen by organic substances in water resources result in undesirable environment for living organisms. The aim of this study was to evaluate the efficiency of natural wastewater treatment systems and activated sludge for municipal wastewater treatment. Methods: This one year-cross-sectional study was conducted on wastewater treatment plants in Kermanshah province. During the study, sampling of raw sewage and effluent of treatment plant was carried out and the efficiency of treatment plant was evaluated by measuring TSS, BOD5 and COD. All the sampling and testing procedures were adopted from the standard method. Findings: The results showed that the annual average of BOD5 in effluent for Wetland, stabilization pond, extended aeration and conventional activated sludge was 55, 25, 21 and 23 mg/l respectively. Also the annual average was 143, 43, 40 and 40 mg/lfor COD, and 47, 101, 40 and 33 mg/l for TSS, respectively. For COD removal the conventional activated sludge (86.97%) and Wetland (61.6%) were the most efficient and least efficient systems. For BOD5 removal the stabilization pond (85.18%) and Wetland (72.01%) were the most efficient and least efficient systems. The BOD5 / COD ratio in influent were respectively 0.56, 0.62, 0.59 and 0.55 in these systems. Discussion and Conclusion: In all of the mentioned wastewater treatment systems, the effluent parameters comply with the Iran environmental protection agency standards and it can be reused or discharged to water bodies. Also it can be concluded that, for above-mentioned parameters the removal efficiency of natural systems was more than activated sludge