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[Çؿܺ¸°í¼­] Á¤¼öÀå ¼Òµ¶Á¦ ¡®Â÷¾Æ¿°¼Ò»ê³ªÆ®·ý¡¯ °ø±Þ, OSG ½Ã½ºÅÛÀÌ ¹úÅ© ÀÌ¼Û ¹æ¹ýº¸´Ù ¾ÈÀü
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Global Issue Technology


¡°Á¤¼öÀå ¼Òµ¶Á¦¡®Â÷¾Æ¿°¼Ò»ê³ªÆ®·ý¡¯°ø±Þ
OSG ½Ã½ºÅÛÀÌ ¹úÅ© ÀÌ¼Û ¹æ¹ýº¸´Ù ¾ÈÀü¡±
                                                                                                                

À¯Áöº¸¼ö ¿ëÀÌ ¡¦ 1¡­2³â ³» ÅõÀÚ±Ý¾× È¸¼ö °¡´ÉÇÑ °æÁ¦Àû È¿°ú ÀÖ¾î
»ó¾÷¿ë Â÷¾Æ¿°¼Ò»ê³ªÆ®·ýÀÇ ³ôÀº pH´Â ź»êÄ®½· ½ºÄÉÀÏ ¹ß»ý ¿øÀÎ

 

 

¿°¼Ò°¡½º¸¦ ´Ù¸¥ ÇüÅÂÀÇ Á¦Ç°À¸·Î ´ëüÇÏ´Â °úÁ¤¿¡¼­ Èñ¼® »óÅÂÀÇ Â÷¾Æ¿°¼Ò»ê³ªÆ®·ý(ÀÌÇÏ Â÷¾Æ¿°¼Ò»ê) ¿ë¾×À» Ç÷£Æ® ÇöÀå¿¡¼­ Á÷Á¢ Á¦Á¶ÇÏ´Â °ÍÀ» OSG(On-Site Generation) ±â¼úÀ̶ó°í ÇÑ´Ù. ¹Ì±¹ Ķ¸®Æ÷´Ï¾ÆÀÇ ÄÁ¼³Æà ±â¾÷ Ä«·Ñ·Î ¿£Áö´Ï¾î(Carollo Engineers) ¼Ò¼Ó Ä«¸¦¸® Ä«ÀÌ·ÎÁî(Khalil Kairouz)¿Í UDECM»ç ´ëÇ¥ ¾Ë¹öÆ® ¶ó¿ì(Albert Rau), ÀÌÅ»¸®¾Æ ¿£Áö´Ï¾î¸µ ÄÁ¼³ÅÏÆ®ÀÎ À©ÇÁ·¹µå ÄÚÆ÷µµ(Winfred Kpodo)´Â ¡ºWater Technology¡» 2016³â 6¿ùÈ£¿¡¼­ ´ë¿ë·® ¹úÅ© À̼ۿ¡ ´ëÇÑ OSG ¹æ½ÄÀÇ À塤´ÜÁ¡À» ¼Ò°³Çß´Ù. ±× ³»¿ëÀ» ¹ø¿ªÇß´Ù.  [ÀÚ·áÁ¦°ø¡¤¹ø¿ª = ±è´ö¿¬ º»Áö ÆíÁýÀ§¿ø]

¿°¼Ò´Â ¿°¼Ò°¡½º, Â÷¾Æ¿°¼Ò»ê(¾×»ó), Â÷¾Æ¿°¼Ò»êÄ®½·(°í»ó) µîÀÇ Á¦Ç°À¸·Î ÆǸŵǰí ÀÖ´Ù. °¡Àå ÀϹÝÀûÀÎ ¼Òµ¶Á¦·Î »ç¿ëµÇ´Â ¿°¼Ò°¡½º´Â Å×·¯¸®½ºÆ®ÀÇ °ø°Ý¸ñÇ¥ ¹× ¾ÈÀü»ó ¹®Á¦°¡ ÀÖ´Â Á¦Ç°À¸·Î Àνĵǰí ÀÖÀ¸¸ç, µû¶ó¼­ »ç¿ë»ó ±ÔÁ¦°¡ ¸Å¿ì ±î´Ù·Ó´Ù. ±× °á°ú ¸¹Àº »ç¿ëÀÚµéÀÌ º¸´Ù ¾ÈÀü¼ºÀÌ ÀÖ´Â ¼Òµ¶Á¦ ´ëü°¡ °¡´ÉÇÑ Á¦Ç°À¸·Î ÀüȯÀ» °í·ÁÇÏ°í ÀÖÀ¸¸ç, ¹Ì±¹ Á¤ºÎ¿¡¼­µµ ÀÌ·¯ÇÑ ÀüȯÀ» Áö¿øÇÏ°í ÀÖ´Ù.

¿°¼Ò°¡½º ´ëü¿ëÀ¸·Î °¡Àå ÀϹÝÀûÀÎ ¼±ÅÃÀº Â÷¾Æ¿°¼Ò»ê(¾×»ó) Á¦Ç°À̸ç, ÀÌ´Â ¿°¼Ò³óµµ°¡ 10¡­15%ÀÎ À¯¸®À¯È¿¿°¼Ò(Free Available Chlorine, FAC) »óÅ·Πº¸Åë ´ë¿ë·® ¹úÅ©(bulk)·Î ¿î¼Û ¹× °ø±ÞµÈ´Ù. ÇÑÆí, ¼Ò±Ý ÀÚü¸¦ Ư¼ö Àü±â¼¿ ÀåÄ¡¿¡ Åë°ú½ÃÄÑ 1% ÀÌÇÏÀÇ FAC »óÅÂÀÎ Àú³óµµ Â÷¾Æ¿°¼Ò»êÀ» ÇöÀå¿¡¼­ Á÷Á¢ »ý»êÇϱ⵵ ÇÑ´Ù.

´ë¿ë·® ¹úÅ©·Î Ãë±ÞµÇ´Â Â÷¾Æ¿°¼Ò»êÀº ¿ø¾× Â÷¾Æ¿°¼Ò»ê(delivered hypochlorite), »ó¾÷¿ë Â÷¾Æ¿°¼Ò»ê(commercial hypochlorite), ³óÃà Â÷¾Æ¿°¼Ò»ê(concentrated hypochlorite) ¹× ´ë¿ë·® Ç¥¹éÁ¦(bulk bleach) µî ´Ù¾çÇÑ ÇüÅ·Π°ø±ÞµÈ´Ù. ÀÌ¿¡ ¹ÝÇØ Èñ¼® »óÅÂÀÇ Â÷¾Æ¿°¼Ò»ê ¿ë¾×À» Ç÷£Æ® ÇöÀå¿¡¼­ Á÷Á¢ Á¦Á¶ÇÏ´Â °ÍÀº OSG(On-Site Generation) ±â¼úÀ̶ó ºÎ¸¥´Ù.

¿°¼Ò°¡½º¸¦ ´Ù¸¥ Á¦Ç°À¸·Î ´ëüÇÏ´Â °úÁ¤¿¡¼­ ¼±Åà °áÁ¤ÀÇ ÁßÁ¡ »çÇ×Àº Á¦Ç° ¾ÈÀü¼º, À¯Áöº¸¼ö ¿ä±¸ ¼öÁØ ¹× ±¸ÀÔ °¡°ÝÀÌ´Ù. ÀϺδ Â÷¾Æ¿°¼Ò»êÀÇ ´ë¿ë·® ¹úÅ© À̼ÛÀ» °¡Àå ¾ÈÀüÇÏ°í ºñ¿ëÀÌ Àû°Ô µå´Â ¹æ¹ýÀ¸·Î ¾Ë°í ÀÖÀ¸³ª, ±×µ¿¾ÈÀÇ ºñ±³ Æò°¡¿¡ ÀÇÇϸé ÇöÀå »ý»ê¿¡ ÀÇÇÑ OSG ¹æ½ÄÀÌ º¸´Ù ¾ÈÀüÇÒ »Ó¸¸ ¾Æ´Ï¶ó À¯Áöº¸¼ö°¡ ´õ¿í ¿ëÀÌÇϸç 1¡­2³â ³»¿¡ ÅõÀÚ È¸¼ö°¡ °¡´ÉÇÑ °æÁ¦Àû È¿°ú°¡ ÀÖ´Â °ÍÀ¸·Î µå·¯³µ´Ù.

À̹ø ¼Ò°³´Â ±âÁ¸ ´ë¿ë·® ¹úÅ© À̼ۿ¡ ´ëÇØ OSG ¹æ½ÄÀÇ À塤´ÜÁ¡À» °ËÅäÇÏ°íÀÚ ÇÏ´Â °ÍÀ¸·Î, ÀÌ´Â ÄÁ¼³Æà ¾÷ü, ¿£Áö´Ï¾î, Á¤Ã¥ÃßÁøÀÚ ¹× ¼³ºñ´ã´çÀÚµéÀÌ ´ëü¿ë Á¦Ç°ÀÇ ºñ¿ëÀ» »êÃâÇÏ°í °æÁ¦Àû È¿°ú¸¦ Æò°¡ÇÏ´Â µ¥ ÈǸ¢ÇÑ ÁöħÀÌ µÉ °ÍÀÌ´Ù. ¶ÇÇÑ ´ëü¿ë Á¦Ç°À¸·ÎÀÇ ÀüȯÀ» À§ÇÑ Á¤ºÎ ¹× ÁöÀÚüÀÇ Æݵù È®º¸ ¹× ¼ö¸³¿¡µµ À¯¿ëÇÑ ¼ö´ÜÀÌ µÉ °ÍÀÌ´Ù.

 

Chlorine is purchased commercially as gaseous chlorine, liquid sodium hypochlorite or calcium hypochlorite(solid). Chlorine gas, still the most common form of disinfectant, has been recognized as a potential terrorist target and safety problem and is heavily regulated. As a result, many facilities have switched or are considering switching to safer disinfection alternatives, and federal actions are encouraging this conversion.

The most common choice for those converting away from chlorine gas is sodium hypochlorite, which is available delivered in bulk at a free available chlorine(FAC) concentration ranging from 10 to 15 percent. It is also possible to generate hypochlorite on-site at a low concentration(less than 1 percent FAC) by passing a brine solution through an electrolytic cell. Hypochlorite as a bulk chemical is referred to by various descriptors, including delivered hypochlorite, commercial hypochlorite, concentrated hypochlorite and bulk bleach. On-site generation of a dilute hypochlorite solution(less than 1 percent) is abbreviated as OSG.

The decision process when evaluating alternatives to chlorine gas focuses on safety, maintenance requirements and costs. Delivered hypochlorite is often perceived as safe, easy and cheap. However, a proper evaluation shows that on-site generation is not only safer than bulk bleach, but also offers significant maintenance advantages and presents a return on investment within one to three years.

This article outlines the benefits and drawbacks of delivered sodium hypochlorite versus OSG. It will help consultants, engineers, city planners and utility personnel evaluate the potential costs and benefits of each disinfection alternative prior to conversion. This type of analysis will also provide the water utility with a valuable tool to secure conversion funding at the federal or state level.

 

¾ÈÀü¼º(Safety)

 

´ë¿ë·® ¹úÅ© À̼ۿ¡ ÀÇÇÑ Â÷¾Æ¿°¼Ò»êÀÇ ¾ÈÀü¼º »çÇ×Àº ¡â¾ÏÀ» À¯¹ß½ÃÅ°´Â ºÎ»ê¹°Áú Çü¼º ¡âÂ÷¾Æ¿°¼Ò»ê ¿ë¾×ÀÇ ³óÃà Çö»ó ¡âÀ¯Çع°ÁúÀÇ ÀÌ¼Û ¹× ¿î¹Ý ¡âÁö¿ª»çȸÀÇ ¾ÈÀü¿¡ ´ëÇÑ ºñÆÇ ¿©·Ð ¡âÀúÀå ¹× ¿îÀü °úÁ¤¿¡¼­ ¹ß»ýµÇ´Â ¾ÈÀü»óÀÇ ¹®Á¦ µîÀ¸·Î ºÐ·ùµÈ´Ù. ÇÑÆí, OSG ¹æ½ÄÀ¸·Î ¹ß»ýÇÏ´Â ¾ÈÀü Ç׸ñÀº ¼ö¼Ò°¡½º ¹ß»ý ¹× Àü±â Ãë±Þ½Ã ¾ÈÀü»ó ¹®Á¦°¡ ÀÖ´Ù. ÀÌ µÎ °¡Áö ¹æ½ÄÀ» ºñ±³ÇÑ °á°ú¿¡ µû¸£¸é OSG ¹æ½ÄÀº ¹úÅ© ÀÌ¼Û ¹æ½Äº¸´Ù ÈξÀ ¾ÈÀüÇÑ °ÍÀ¸·Î µå·¯³µ´Ù.

 

Relevant safety topics for delivered hypochlorite include the potential formation of cancerous by-products, the concentration of the hypochlorite solution, shipping and transfer of hazardous materials, community safety concerns, and storage and operational safety. Relevant safety topics for OSG include hydrogen and electrical safety. Comparison of the two alternatives shows that OSG is a much safer alternative than delivered hypochlorite.

 

¾Ï À¯¹ß ºÎ»ê¹°ÁúÀÇ Çü¼º(Cancerous Byproducts)

 

ÀÏ¹Ý »ó¾÷¿ë Â÷¾Æ¿°¼Ò»êÀ» »ý»êÇÏ´Â °øÁ¤Àº ´Ù´Ü°è °øÁ¤À¸·Î ±¸¼ºµÈ´Ù. ¼Ò±Ý¹°À» Àü±âºÐÇØÇÏ¿© ¿°¼Ò¹°ÁúÀ» ¹ß»ý½ÃÅ°´Â °øÁ¤À¸·Î ½ÃÀÛÇϸç, ÀÌ´Â OSG ¹æ½Ä¿¡¼­µµ µ¿ÀÏÇÑ °øÁ¤À¸·Î »ý»êµÈ´Ù. ¹ß»ýµÈ ¿°¼Ò¹°ÁúÀº °¡¼º¼Ò´Ù(sodium hydroxide)¿Í ¹ÝÀÀÇÏ¿© Â÷¾Æ¿°¼Ò»êÀÌ µÈ´Ù.

°£È¤ ¹Ù´å¹° ÀÚü°¡ Â÷¾Æ¿°¼Ò»ê »ý»êÀ» À§ÇÑ ¼Ò±Ý¿ë¾×À¸·Î »ç¿ëµÇ´Âµ¥ ÀÌ´Â ÀÚ¿ø ÃëµæÀÌ Ç³ºÎÇÏ°í ºñ¿ëÀÌ Àú·ÅÇϱ⠶§¹®ÀÌ´Ù. ±×·¯³ª ¹Ù´å¹°¿¡´Â ºê·ÒÈ­¹°(bromide)ÀÌ ¸¹ÀÌ ÇÔÀ¯µÇ¾î ÀÖ¾î Àü±âºÐÇØ °úÁ¤¿¡¼­ ºê·Ð»ê¿°(bromate)À¸·Î º¯È¯µÈ´Ù. µû¶ó¼­ ÀϺΠ»ó¾÷¿ë Ç¥¹éÁ¦ Á¦Ç°¿¡¼­´Â ºê·Ð»ê¿° ¹°Áú ÇÔÀ¯À²ÀÌ EPAÀÇ ¸Ô´Â¹° ±âÁØÀ» ÃÊ°úÇÏ¿© ¾Ï À¯¹ß¼º Á¦Ç°À¸·Î ºÐ·ùµÇ°í ÀÖ´Ù.

¹Ý¸é, OSG ¹æ½ÄÀÇ Àü±âºÐÇØ °úÁ¤¿¡¼­ »ç¿ëµÇ´Â ¼Ò±ÝÀº ÀûÀýÇÏ°Ô Á¶ÀýÇÏ´Â °ÍÀÌ °¡´ÉÇÏ´Ù. OSG ½Ã½ºÅÛ¿¡¼­ ¸Ô´Â¹° 󸮿ëÀ¸·Î »ç¿ëµÇ´Â õ¿¬ ¼Ò±ÝÀº ºê·Ð»ê¿° ¹ß»ý À§Ç輺À» ´ëÆø ÁÙÀÎ ¼öÁØÀÇ ºê·ÒÈ­¹°ÀÌ ÇÔÀ¯µÇ¾î ÀÖ´Ù.

¹úÅ© ÀÌ¼Û ¹× OSG ¹æ½Ä ¸ðµÎ ¹ß¾Ï¼º Àü±¸¹°ÁúÀ» °¡Áø ÃÑÆ®¸®ÇҷθÞź(Total Trihalomethanes, TTHMs)À» ¹ß»ý½ÃÅ°³ª, ½ÇÇè °á°ú OSG ¹æ½ÄÀÌ TTHMs ¹ß»ýÀ» ÁÙÀÌ´Â °ÍÀÌ È®ÀεÆÀ¸¸ç, ÀÌ´Â OSG ½Ã½ºÅÛ¿¡¼­ ¿ø¼ö °ø±Þ°ú ÇÔ²² ÁÖÀԵǴ ¿°¼Ò·®À» ÁÙÀÏ ¼ö Àֱ⠶§¹®À¸·Î ÁüÀ۵ȴÙ.

   
¡ã ¿°¼Ò°¡½º¸¦ ´Ù¸¥ ÇüÅÂÀÇ Á¦Ç°À¸·Î ´ëüÇÏ´Â °úÁ¤¿¡¼­ Èñ¼® »óÅÂÀÇ Â÷¾Æ¿°¼Ò»ê³ªÆ®·ý ¿ë¾×À» Ç÷£Æ® ÇöÀå¿¡¼­ Á÷Á¢ Á¦Á¶ÇÏ´Â °ÍÀ» OSG ±â¼úÀ̶ó°í ÇÑ´Ù.

 

The production of commercial strength hypochlorite is a multistep process, starting with electrolysis of a brine solution to form chlorine that is similar to the process utilized by OSG. This chlorine is then reacted with sodium hydroxide to create sodium hypochlorite.

Often, seawater is used as the brine source for production of hypochlorite because of its availability and low cost. However, seawater is high in bromide concentration, which ultimately converts to bromate during the electrolytic process.

Thus, some commercial bleaches may exceed the EPA drinking water limits for bromate, which has been classified as a cancer-causing agent. In contrast, the salt used during the electrolytic process of OSG can be carefully controlled. The food grade and solar salts more commonly used with OSG systems for potable water treatment have bromide levels that are far below the levels of concern for bromate formation.

Delivered hypochlorite and OSG will form total trihalomethanes(TTHMs) in water with organic precursors. However, evidence shows that OSG reduces the formation of TTHMs, most likely due to the ability to reduce the chlorine added to the water supply with OSG while maintaining an adequate disinfectant residual.

 

¿°¼Ò³óµµ(Chlorine Concentration) 
 
»ó¾÷¿ëÀÇ Â÷¾Æ¿°¼Ò»êÀº °í³óÃà »óÅÂÀ̸ç pH°¡ ³ô´Ù. ÀϹÝÀûÀÎ ¿°¼Ò³óµµ´Â 10¡­15%, Áï 10¸¸¡­15¸¸§·/L ¼öÁØÀ̸ç pH°ªÀº ÀϹÝÀûÀ¸·Î 12¡­13 ¼öÁØÀÌ´Ù. ¹Ý¸é¿¡ OSG Á¶°Ç¿¡¼­´Â 0.25¡­0.8% ¼öÁØÀÎ 2õ500¡­8õ§·/L ³óµµ·Î ¸¸µé¾îÁö¸ç, ÀÌ´Â À§Çؼº¹°Áú ¾ÈÀü ±âÁØÀÎ 1% º¸´Ù ÀûÀº °ªÀÌ´Ù. ½ÇÁ¦·Î ³·Àº ³óµµ·Î ÇöÀå¿¡¼­ Á÷Á¢ »ý»êµÇ´Â Â÷¾Æ¿°¼Ò»ê¿¡ ´ëÇÑ Á¦ÇÑ ±ÔÁ¤Àº ¾ø´Ù. ÇÑÆí, OSG ¹æ½ÄÀÇ pH´Â 9 ¼öÁØÀ¸·Î, »ó¾÷¿ë Ç¥¹éÁ¦º¸´Ù 5¡­6 Á¤µµ ³·Àº ¼öÄ¡¸¦ º¸¿©ÁØ´Ù.

Commercial hypochlorite is highly concentrated and high in pH. Typical chlorine concentrations range from 10 to 15 percent, or 100,000 to 150,000 milligrams/liter(mg/L), and pH values of 12 to 13 are common. In contrast, OSG is generated at a concentration ranging from 0.25 to 0.8 percent, or 2,500 to 8,000 mg/L, far below the 1 percent safety threshold of the Hazardous Communications Standard. In fact, no regulatory requirements are associated with hypochlorite generated on-site at low chlorine concentrations. In addition, the pH value of OSG is around 9, only two orders of magnitude away from a neutral pH, rather than 5 to 6 orders of magnitude as with commercial bleach.

 

À¯Çؼº È­Çй°ÁúÀÇ ¿î¼Û°ú À̵¿(Shipping and Transfer of Hazardous Chemicals)

 

¹úÅ© ÀÌ¼Û È­Çй°ÁúÀÇ °ø±Þ ½Ã ´ë·® À¯Çع°ÁúÀÇ ÀÌ¼Û ¹× ÀúÀåÀ» À§ÇÑ ½Ã¼³ÀÌ ÇÊ¿äÇϸç, ÀÌ¿¡ µû¸¥ »ç°í À§Ç輺ÀÌ Å©´Ù. ¿°¼Ò¿¬±¸Çùȸ(Chlorine Institute Inc.)´Â ÀÌ ¹°ÁúÀ» Ãë±ÞÇÏ°í Èñ¼®½ÃÅ°´Â ÀýÂ÷¿¡ ´ëÇÑ °¡À̵å¶óÀÎÀ» ¾ö°ÝÈ÷ ÁؼöÇϵµ·Ï ±ÇÀåÇÏ°í ÀÖÀ¸¸ç, °ü·Ã ³»¿ëÀ» À¥»çÀÌÆ®(www.chlorineinstitute.org) »ó¿¡ °ÔÀçÇÏ°í ÀÖ´Ù.

¹Ý¸é, OSG ½Ã½ºÅÛ¿¡¼­´Â ¹úÅ© À̼ۿë Á¦Ç°º¸´Ù 15¹è ÀÌ»ó Èñ¼®µÈ ³óµµ·Î Â÷¾Æ¿°¼Ò»ê ¿ë¾×À» »ý»êÇÏ°í ÀÖ´Ù. ÀϹÝÀûÀ¸·Î OSG ½Ã½ºÅÛ¿¡¼­´Â 24½Ã°£ À̳»ÀÇ ÀúÀåÀ» ¸í½ÃÇÏ°í ÀÖÀ¸¸ç, ÀÌ·Î½á ´ë·® À¯Ãâ¿¡ ´ëÇÑ À§Ç輺ÀÌ ÁÙ¾îµé°Ô µÈ´Ù.

¹úÅ© ÀÌ¼Û ¹æ½ÄÀÇ Â÷¾Æ¿°¼Ò»ê¿¡ ÀÇÇÑ »ç°í´Â »ê¼º È­ÇоàÇ°ÀÌ ÀûÀçµÈ ÅÊÅ© Æ®·°À¸·ÎºÎÅÍ Â÷¾Æ¿°¼Ò»ê ÀúÀå ÅÊÅ© ³»¿¡ ÁÖÀԵǴ °æ¿ì, ȤÀº ±× ¹Ý´ë·Î Â÷¾Æ¿°¼Ò»êÀÌ ÀûÀçµÈ Æ®·¹ÀÏ·¯·ÎºÎÅÍ »ê¼º È­ÇоàÇ°ÀÌ µé¾îÀÖ´Â ÅÊÅ© ³»¿¡ ÁÖÀԵǴ °æ¿ì¿¡ ¹ß»ýÇÑ´Ù. ÀÌ °úÁ¤¿¡¼­ ¿°¼Ò°¡½ºÀÇ ´ë·® À¯ÃâÀÌ ÀϾ´Âµ¥, ÀϹÝÀûÀ¸·Î ¿°¼Ò°¡½º´Â pH°¡ ³·¾ÆÁú ¶§ Â÷¾Æ¿°¼Ò»êÀÌ »ê°ú Á¢ÃËÇÏ¸ç ¹ß»ýÇÑ´Ù.

º¸´Ù ¾ÈÀüÇÏ´Ù´Â Åë³ä¿¡µµ ³óÃàµÈ Â÷¾Æ¿°¼Ò»êÀº ¿©ÀüÈ÷ À¯ÇØÇÑ È­Çй°ÁúÀ̶ó´Â °ÍÀ» º¸¿©ÁÖ´Â ¸î °¡Áö »ç·Ê°¡ ÀÖ´Ù. Á¶Áö Ŭ¸®Æ÷µå È­ÀÌÆ®(George Clifford White)´Â ±×ÀÇ Àú¼­¿¡¼­ Á¤¼öÀå¿¡¼­ ¹ß»ýÇÑ °¡Àå Å« ¿°¼Ò°¡½º ´©Ãâ »ç°í´Â ¿°¼Ò°¡½º »ç¿ë¿¡ ÀÇÇÑ °ÍÀÌ ¾Æ´Ï¶ó Â÷¾Æ¿°¼Ò»ê ³ªÆ®·ý »ç¿ë¿¡ ÀÇÇÑ °ÍÀ̶ó°í ÁÖÀåÇÏ°í ÀÖ´Ù. ÀÌ »ç°í´Â ¹Ì±¹ µ¿ºÎÁö¿ª ´ë±Ô¸ð Á¤¼öÀå¿¡¼­ ¹ß»ýÇÑ »ç°íÀÌ´Ù. ¿°È­Á¦2ö(ferric chloride, pH4)ÀÇ ÅÊÄ¿ Æ®·°ÀÌ ½Ç¼ö·Î Â÷¾Æ¿°¼Ò»ê ÅÊÅ©¿¡ ºÎ¾îÁ³´Âµ¥ ÀÌ·Î ÀÎÇØ Â÷¾Æ¿°¼Ò»êÀÇ pH°¡ 12¿¡¼­ 5·Î ±Þ°ÝÈ÷ ³·¾ÆÁ® 5õ455§¸ÀÇ Â÷¾Æ¿°¼Ò»êÀÌ ¿°¼Ò°¡½º·Î ´ë·® ´©ÃâµÇ´Â »ç°í°¡ ¹ß»ýÇß´Ù.

ÀÌ ¿Ü¿¡µµ ¹Ì±¹ ³» °øÀå¿¡¼­ ¿°¼ÒÁ¦°Å¿ë È­ÇÐÁ¦ÀÎ ¾ÆȲ»ê ¼ö¼Ò³ªÆ®·ý(sodium bisulfite) ¹°ÁúÀÌ Â÷¾Æ¿°¼Ò»ê ÅÊÅ©¿¡ À߸ø ÅõÀÔµÇ¾î ¾à 50¸¸ ´Þ·¯ÀÇ ¼ÕÇØ°¡ ¹ß»ýÇÑ »ç°Çµµ ÀÖ¾ú´Ù. 2003³â¿¡´Â ¿ÀÇÏÀÌ¿ÀÁÖ¿¡¼­ ÇÑ ÀÛ¾÷ÀÚ°¡ ½Ç¼ö·Î 5°¶·±ÀÇ Â÷¾Æ¿°¼Ò»êÀ» 15°¶·±ÀÇ ÇÏÀ̵å·ÎÇ÷οÀ·Î±Ô»ê(hydrofluorosilicic)°ú È¥ÇÕ½ÃÄÑ À¯µ¶¼º ¿°¼Ò°¡½º°¡ ¹ß»ý, ÀÛ¾÷ÀÚ´Â Ä¡·á¸¦ À§ÇØ º´¿ø¿¡ ÀÔ¿øÇÏ´Â Àϵµ ÀÖ¾ú´Ù.

ÀÌ¿¡ ÀϺΠÇ÷£Æ® ÀÛ¾÷ÀÚµéÀº º°µµ·Î 2°³ÀÇ ÀÚ¹°¼è¸¦ ÁغñÇÏ¿© Ãë±Þ»óÀÇ »ç°í À§ÇèÀ» ÃÖ¼ÒÈ­ÇÏ°í ÀÖ´Ù. ¿°¼Ò¿¬±¸Çùȸ´Â ¶ÇÇÑ ¡âÀÛ¾÷ÀÚ¿¡ ´ëÇÑ ±³À° °­È­ ¡âº°µµ ÀÛ¾÷ÀÚ¿¡°Ô ºñ»ó¿ë ÀÚ¹°¼è¸¦ ÁÖ¾î ÅÊÅ© ÁÖÀÔ ½Ã ¾ÈÀüÀåÄ¡ È®º¸ ¡âÀ̼ۿë Æ®·°À̳ª ÅÊÅ© ³»¿ë¹° È®ÀÎÀ» À§ÇÑ ¼ÛÀåÀ̳ª ¸Þ¸ðÆÇ °Ë»ç¸¦ ½Ç½ÃÇϴ üũ¸®½ºÆ® Áغñ µîÀ» ±ÇÀåÇÏ°í ÀÖ´Ù.

¹Ý¸é OSG ½Ã½ºÅÛ¿¡¼­ »ç¿ëµÇ´Â ¼Ò±ÝÀº À¯ÇØÈ­Çй°Áú·Î ±ÔÁ¤µÇ¾î ÀÖÁö ¾ÊÀ¸¸ç ÀÌ ¹°Áú¿¡ ´ëÇÑ »ç°í »ç·Ê´Â ÀÌÁ¦²¯ º¸µµµÈ ¹Ù ¾ø´Ù. Áï OSG ½Ã½ºÅÛ¿¡¼­ »ç¿ëµÇ´Â ¼Ò±ÝÀº ¹úÅ©¿¡ ÀÇÇÑ Â÷¾Æ¿°¼Ò»êÀÇ ¿î¼Û ¹× À̵¿¿¡ °ü·ÃµÈ ¾ÈÀü»óÀÇ »ç°í¹ß»ý À§Çè°ú ÀüÇô °ü·Ã¼ºÀÌ ¾ø´Ù.

   
¡ã ¿°¼Ò°¡½º ´ëü¿ëÀ¸·Î °¡Àå ÀϹÝÀûÀÎ ¼±ÅÃÀº Â÷¾Æ¿°¼Ò»ê³ªÆ®·ý(¾×»ó) Á¦Ç°À̸ç, ÀÌ´Â ¿°¼Ò³óµµ°¡ 10¡­15%ÀÎ À¯¸®À¯È¿¿°¼Ò »óÅ·Πº¸Åë ´ë¿ë·® ¹úÅ©(bulk)·Î ¿î¼Û¡¤°ø±ÞµÈ´Ù.

 

Ordering a chemical in bulk necessitates the transfer and storage of large quantities of hazardous material, increasing the likelihood of an accident. The Chlorine Institute Inc., a nonprofit trade association of companies created to support the chlor alkali industry and public safety, recommends developing procedures for handling and diluting sodium hypochlorite and provides guidelines on its website. In contrast, OSG produces a hypochlorite solution at a concentration that is at least 15 times more dilute than delivered hypochlorite. Typically, OSG systems specify less than 24 hours¡¯ worth of storage, reducing the likelihood of a large spill.

Accidents with delivered hypochlorite have occurred when a tank truck of acid or acidic chemical was unloaded into a sodium hypochlorite solution storage tank, or, conversely, when a trailer of sodium hypochlorite solution was unloaded into a tank containing acidic chemicals. The result of this scenario is a massive chlorine gas plume. Chlorine gas is produced from hypochlorite when the pH is reduced, which occurs with the introduction of acid. The following examples demonstrate that concentrated hypochlorite is still a hazardous chemical, despite its perception as a safer alternative.

According to George Clifford White in his Handbook of Chlorination and Alternative Disinfectants, one of the largest chlorine gas leaks that ever occurred at a water treatment plant was due to the use of sodium hypochlorite, not chlorine gas. The accident occurred at a large treatment plant in the East, when a tanker truck load of ferric chloride(pH = 4.0) was dumped into the hypo tank by mistake. This lowered the hypo pH from about 12 to 5 almost instantly, releasing approximately 5455 kilograms (12,000 pounds) of hypochlorite as chlorine gas in one great mass.

At a facility in the U.S., approximately $500,000 in damages occurred when sodium bisulfite, a dechlorination chemical, was accidentally delivered into a hypochlorite tank.

In 2003 in Ohio, an employee mistakenly mixed 5 gallons of sodium hypochlorite with 3.96 liters(15 gallons) of hydrofluorosilicic acid, causing a toxic fume(chlorine gas release). He was taken to the hospital for treatment while a hazardous materials (hazmat) crew secured the chemicals.

Some operators minimize the risk of operator error by requiring two separate keys for delivery. Other recommendations from the Chlorine Institute Inc. include extensive operator training, secured devices on tank loading lines with a controlled key given to specified operators and checklists requiring the confirmation of the chemical name by examination of the shipping papers and the placarding of the truck or tank car.

By contrast, salt, the feedstock for OSG equipment, is not classified as a hazardous chemical, and no industrial accidents involving salt have been reported to date. Salt has none of the safety concerns associated with the shipping and transfer of bulk hypochlorite. 
 

ÀÌ¼Û ½Ã½ºÅÛ¼­ °¡½º¹ß»ý ÆßÇÁ¡¤¹ëºê¡¤ÅÊÅ©¡¤¹è°üÀç °íÀ塤°áÇÔ ¿øÀÎ
ÀÌ¼Û °ø±Þ ¶óÀÎ, ºñ±Ý¼Ó¼º ¶óÀÌ´× È£½º »ç¿ë Á¦Ç° ¾ÈÀü¼º À¯Áö ÇʼöÀû
OSG, ¹úÅ© À̼ۺ¸´Ù TTHMs ¹ß»ý·® Àû¾î¡¦¿°¼ÒÁÖÀÔ·® ÁÙÀÏ ¼ö ÀÖ¾î 

  

Áö¿ª»çȸÀÇ °ÆÁ¤(Community Concerns)

 

Áö¿ª»çȸ ÁֹΠ¹× Áö¿ª °ø¹«¿øµéÀº ÀϹÝÀûÀ¸·Î ¿°¼Ò È­Çй°ÁúÀÇ ¿î¼Û ¹× º¸°ü¿¡ ´ëÇÏ¿© ¹Ý´ëÇÏ´Â ÀÔÀåÀ» ÃëÇÑ´Ù. ³ª¾Æ°¡ ó¸®Àå¿¡¼­ÀÇ »ç°í À§Ç輺 Áõ°¡¿¡ ´õÇØ ¹úÅ© ÀÌ¼ÛµÈ È­Çй°Áú »ç¿ëÀº Áö¿ª»çȸÀÇ ºÒ¾È°¨À» ´õ¿í ÁõÆø½ÃÅ°°í ÀÖ´Ù.

¿¹¸¦ µé¾î 2006³â 5¿ù Åػ罺ÁÖ ¿À½ºÆ¾¿¡¼­´Â °í¼Óµµ·Î¿¡¼­ ÅÊÄ¿ Æ®·°ÀÌ Àüº¹µÈ »ç°í°¡ ¹ß»ý, ÅÊÅ©·ÎºÎÅÍ À¯ÃâµÈ ¾×»ó ¿°¼Ò¹°Áú 󸮸¦ À§ÇØ À§Çè¹°Áú Ãë±ÞÆÀÀÌ ¿ÀÈÄ ´ëºÎºÐÀÇ ½Ã°£À» ½ñ¾Æ ó¸®ÇÑ ÀûÀÌ ÀÖ´Ù. ´ç½Ã Æ®·°±â»ç´Â º´¿ø¿¡ Èļ۵Ǿî È£Èí±â°ü Ä¡·á¸¦ ¹Þ¾ÒÀ¸¸ç ÀÌ·¯ÇÑ Àå½Ã°£ ³ëÃâ·Î ÁÖÀ§°¡ ¸ðµÎ ¿µÇâÀ» ¹Þ°Ô µÇ¾î ÀαÙÀÇ ÁֹΠ¹× ÇлýµéÀÌ ¸ðµÎ ´ëÇÇÇÏ´Â ¼Òµ¿ÀÌ ÀϾ´Ù.

 

Community members and prominent citizens are typically against the transport and storage of chlorine chemicals. Besides increasing the potential for accidents at the treatment plant, use of a bulk chemical presents an increased risk for the larger community.

For example, on May 26, 2006, in Austin, Texas, a hazmat team worked most of the afternoon to contain a liquid chlorine leak from a tanker truck that closed down U.S. Highway 290. The truck driver himself was taken to the hospital and treated for breathing problems. Residents and students had to be evacuated since the leak impacted an elementary school, middle school and high school.

 

ÀúÀå ¹× ¿îÀü»óÀÇ ¾ÈÀü¼º(Storage and Operational Safety)

 

¿°¼Ò°¡½º ¹èÃâÀº »ê¼º¹°ÁúÀÌ Ã·°¡µÇ´Â °æ¿ì»Ó¸¸ ¾Æ´Ï¶ó Â÷¾Æ¿°¼Ò»ê ¹°Áú¿¡ ¹°ÀÌ °ø±ÞµÇ´Â °æ¿ì¿¡µµ ¹ß»ýÇÑ´Ù. Ķ¸®Æ÷´Ï¾Æ Æ÷¸ð³ª¿¡¼­´Â 1997³â ÅÊÅ©¿¡ Å©·¢ÀÌ ¹ß»ýÇÏ¿© Â÷¾Æ¿°¼Ò»ê³ªÆ®·ýÀÌ ´ë·® ¹èÃâµÇ¾úÀ¸¸ç, Ç÷£Æ® ÀÛ¾÷ÀÚµéÀº ¹èÃâÀ» ¸·À¸·Á ½ÃµµÇßÀ¸³ª °á±¹ ¿°¼Ò°¡½º°¡ ÀÚ¿íÇÏ°Ô ÆÛÁ® ÀαÙÀÇ ¼³ºñµé¿¡ ¿µÇâÀ» ¹ÌÄ£ »ç°í°¡ ¹ß»ýÇß´Ù.

ÇÑÆí, Â÷¾Æ¿°¼Ò»êÀº Èñ¼® °úÁ¤¿¡¼­ Æø¹ß¼ºÀÌ ÀÖÀ¸¸ç °£È¤ ¹ß¿­¹ÝÀÀÀÌ ÀϾ´Ù. 1999³â ´º¸ß½ÃÄÚÀÇ ¾Ë¶ó¸ð°í¸£µµ¿¡¼­ Ç¥¹éÁ¦ È­ÇоàÇ° À̼۰úÁ¤¿¡¼­ÀÇ Æø¹ß·Î 5¸íÀÇ ÀÛ¾÷ÀÚ°¡ ºÎ»ó´çÇßÀ¸¸ç 1¸íÀÌ »ç¸ÁÇÑ »ç°í°¡ ÀÖ¾ú´Ù. ¹úÅ© À̼ÛÀÇ Â÷¾Æ¿°¼Ò»êÀº ¿­¿ø¿¡ ´ëÇÑ ³ëÃâ·Î Æø¹ßÀÌ ÀϾ ¼ö ÀÖÀ¸¸ç, ¼¶À¯ÁúÀÇ ´©´õ±â ¹°ÁúÀÌ Â÷¾Æ¿°¼Ò»ê¿¡ ħÀûµÇ¾î ÀÖ´Â °æ¿ì ÀÚ¿¬¹ßÈ­°¡ ¹ß»ýÇÒ ¼öµµ ÀÖ´Ù.

Â÷¾Æ¿°¼Ò»ê³ªÆ®·ýÀÇ ÀÚ¿¬ÀûÀÎ ¿­È­·Î ¹ß»ýÇÏ´Â ¿°¼Ò°¡½º ȤÀº ÀÌ¼Û¿ë ½Ã½ºÅÛ¿¡¼­ÀÇ ´©¼³·Î ¹ß»ýÇÏ´Â °¡½º´Â ȯ±â½Ã¼³ÀÌ ¾ø´Â Àå¼Ò¿¡ ³ëÃâµÈ ÀÛ¾÷Àڵ鿡°Ô °Ç°­»ó À§Çظ¦ ÁØ´Ù. ÆßÇÁÀå ȤÀº ¿©°úÇ÷£Æ®ÀÇ ÅͳΠ³» ¼³ºñ µî Â÷´ÜµÈ Áö¿ªÀÌ ½ÇÁ¦ À§Çè Àå¼Ò°¡ µÇ¹Ç·Î ¿°¼Ò°¡½º ¹èÃâ¿¡ ´ëÇÑ ÀûÀýÇÑ ¾ÈÀüÀåÄ¡°¡ ¿ä±¸µÈ´Ù. ÀÌ¿¡ ¸¹Àº ÁöÀÚüµéÀº Â÷¾Æ¿°¼Ò»ê¿¡ ´ëÇÑ º¸È£ÀåÄ¡·Î º°µµ °Ý³³ ¼³ºñ ¼³Ä¡¸¦ ¿ä±¸ÇÏ°í ÀÖ´Ù.

±×·¯³ª ¸ð¼øÀûÀÌ°Ôµµ Â÷¾Æ¿°¼Ò»êÀº ¿°¼Ò°¡½ºº¸´Ù ´õ ¾È ÁÁÀº ¾ÈÀü»ç°í ÀÌ·ÂÀ» °¡Áö°í ÀÖ´Ù. È£ÁÖ¿¡¼­ 1996³âºÎÅÍ 1998³â±îÁö ¿°¼Ò°¡½º ¹× Â÷¾Æ¿°¼Ò»ê¿¡ ´ëÇÑ ¾ÈÀü»ç°í ±â·ÏÀ» ¼öÁý, ¿¬±¸¡¤°ËÅäÇÑ °á°ú¿¡ µû¸£¸é ¹úÅ© À̼ÛÀÇ Â÷¾Æ¿°¼Ò»ê ¹ß»ý »ç°íÀÇ 90% ÀÌ»óÀº Á¦Á¶»çÀÇ À߸øº¸´Ù´Â »ç¿ëÀÚÀÇ ÀúÀå ¼ÒȦ ȤÀº »ç¿ëÀÚÀÇ °øÁ¤»ó ½Ç¼ö¿¡ ±âÀÎÇß´Ù.

¹Ý¸é ¿°¼Ò°¡½º¿Í ¿¬°üµÈ »ç°í Áß »ç¿ëÀÚÀÇ ½Ç¼ö¿¡ ÀÇÇÑ »ç°í´Â ´Ü 25%¿¡ ±×ÃÆ´Ù. ÀÌ´Â ¹úÅ© À̼ÛÀÇ Â÷¾Æ¿°¼Ò»êÀÌ ¾ÈÀüÇÒ °ÍÀ̶ó´Â À߸øµÈ ÀνÄÀ¸·Î ÀÌ¿¡ ´ëÇÑ ÀÛ¾÷ÀÚÀÇ ±³À°ÀÌ ºÎÁ·Ç߱⠶§¹®À¸·Î »ý°¢ÇÏ°í ÀÖ´Ù. ±ÔÁ¦ ±âÁØÀº ¿°¼Ò°¡½ºº¸´Ù Â÷¾Æ¿°¼Ò»êÀÌ ¾ö°ÝÇÏÁö ¾Ê±â ¶§¹®¿¡ Â÷¾Æ¿°¼Ò»êÀÇ À߸øµÈ Ãë±ÞÀ¸·Î ÀÛ¾÷ÀÚ¸¦ º¸È£Çϱ⿡´Â °£È¤ ºÎÀûÀýÇÑ ±ÔÁ¦¶ó´Â ÁÖÀåµµ ÀÖ´Ù.

   
¡ã ¹úÅ© ÀÌ¼Û ¹× OSG ¹æ½Ä ¸ðµÎ ¹ß¾Ï¼º Àü±¸¹°ÁúÀ» °¡Áø ÃÑÆ®¸®ÇҷθÞź(TTHMs)À» ¹ß»ý½ÃÅ°³ª ½ÇÇè °á°ú OSG ¹æ½ÄÀÌ TTHMs ¹ß»ýÀ» ÁÙÀÌ´Â °ÍÀ¸·Î È®ÀεƴÙ. »çÁøÀº ¹Ì±¹ Wharton-Smith»ç¿¡¼­ Á¦Á¶ÇÑ Â÷¾Æ¿°¼Ò»ê³ªÆ®·ý OSG.


Chlorine gas can be formed not only with the addition of acids, but also by introducing water to commercial strength hypochlorite. In Pomona, California, in 1997, a tank cracked and caused a massive leak of sodium hypochlorite. Plant personnel attempted to wash down the leak and inadvertently caused a chlorine gas cloud, which overcame two auto mechanics next door.

Sodium hypochlorite has been involved in explosions and exothermic reactions during dilution. In 1999 in Alamogordo, New Mexico, a chemical transfer of bleach injured five workers in an explosion and killed one man who died from burn injuries. Exposure of delivered hypochlorite to a heat source can provoke an explosion, and spontaneous ignition can occur when materials such as rags are soaked with commercial strength sodium hypochlorite.
Enclosed areas may also be cause for concern since chlorine gas generated during the natural degradation of sodium hypochlorite or as a result of leaks in the delivery system can overwhelm people in places with inadequate ventilation. ¡°Enclosed areas such as a pump house or a filter plant tunnel are a real hazard, requiring the same safety gear as that required for Cl2 gas.¡±

Many states now require secondary containment for sodium hypochlorite users as an added measure of protection. Ironically, commercial strength hypochlorite has a worse safety record than chlorine gas. Studies reflect an increasing rate of sodium hypochlorite safety incidents over several years.

A study performed in Australia compiled safety incident data on chlorine gas and sodium hypochlorite from 1996 to 1998 via the Emergency Response System. More than 90 percent of delivered sodium hypochlorite accidents involved customer storage or the customer process error, rather than manufacturer error. Conversely, only 25 percent of the incidents associated with chlorine gas were a result of customer errors.

The authors attribute this trend to a lack of operator training compounded by the false perception that delivered sodium hypochlorite is safe. Because regulatory guidelines are less stringent for liquid sodium hypo than chlorine gas, standard risk management practices are often inadequate to protect the operator from the potential mishandling of hypochlorite.

 

¼ö¼Ò°¡½ºÀÇ ¾ÈÀü¼º(Hydrogen Safety)

 

OSG ¹æ½ÄÀÇ Àü±âºÐÇØ °úÁ¤¿¡¼­ ÀϾ´Â ¾ÈÀü»óÀÇ ¹®Á¦´Â ¹Ì¼¼ÇÑ ¾çÀÇ ¼ö¼Ò°¡½º°¡ ¹ß»ýÇÒ ¼ö ÀÖ´Ù´Â Á¡ÀÌ´Ù. ¼ö¼Ò°¡½º´Â ƯÁ¤ ȯ°æ¿¡¼­ Æø¹ß¼ºÀÌ ÀÖ´Ù. ¼ö¼ÒÀÇ Æø¹ßÇÏÇѼ±(LEL)Àº °ø±â ¼Ó ÇÔÀ¯ ±âÁØÀ¸·Î 4.1%À̸ç, Æø¹ß»óÇѼ±Àº(UEL)Àº °ø±â ¼Ó ÇÔÀ¯ ±âÁØÀ¸·Î 74.2%´Ù. ÀÌ´Â °ø±â Áß ¼ö¼ÒÇÔÀ¯·®ÀÌ 4.1%º¸´Ù ÀûÀ¸¸é Æø¹ß¼ºÀÌ ¾øÀ¸¸ç, °ø±â Áß ¼ö¼ÒÇÔÀ¯·®ÀÌ 74.2% ÀÌ»óÀ̸é Æø¹ßÀÌ ÀϾÁö ¾Ê´Â´Ù´Â ÀǹÌÀÌ´Ù. Áï, ¼ö¼Ò ÇÔÀ¯·®ÀÌ 4.1%¡­74.2% »çÀÌÀÏ °æ¿ì ¼ö¼Ò´Â »ê¼Ò°¡ Á¸ÀçÇϴ ȯ°æ¿¡¼­ Æø¹ßÇÏ´Â °æÇâÀÌ ÀÖ´Ù.

¼ö¼Ò°¡½º´Â ¹Ðµµ°¡ 0.069ÀÎ °¡Àå °¡º­¿î ±âü ¿ø¼Ò·Î, ÇÑÁ¤µÈ °ø°£¿¡¼­ »óºÎ·Î ºÎ»óÇÑ´Ù. ¿¬·á¿ë ÀÚ¿øÀ¸·Îµµ »ç¿ëµÇ´Â ¼ö¼Ò´Â OSG ½Ã½ºÅÛÀÇ Àü±âºÐÇØ °úÁ¤¿¡¼­ ¹ß»ýµÇ¹Ç·Î ¾ÈÀüÇÑ ¿îÀüÀ» À§ÇÏ¿© ¹ß»ý ¼ö¼Ò¿¡ ´ëÇÑ ÀûÀýÇÑ ¹èÃâÀåÄ¡ ¼³Ä¡°¡ ÇÊ¿äÇÏ´Ù. ¹èÃâÀåÄ¡°¡ ÀûÀýÇÏ°Ô ¼³Ä¡µÈ ȯ°æ¿¡¼­ ¼ö¼Ò´Â °¨Áö°¡ ¾È µÉ Á¤µµ·Î Èñ¼®µÇ¾î ´ë±â ÁßÀ¸·Î ¹èÃâµÈ´Ù.

µû¶ó¼­ OSG ½Ã½ºÅÛ¿¡¼­ ¼ö¼Ò°¡½º ¹èÃâÀÌ ÀûÀýÇÏ°Ô ÃøÁ¤¡¤¹èÃâµÇ´ÂÁö OSG ½Ã½ºÅÛ Á¦Á¶»ç¿¡ ´ëÇÑ ¹èÃâÀåÄ¡ ¼³°è °Ë»ç°¡ ÀÌ·ç¾îÁ®¾ß ÇÑ´Ù. ±âÁ¸ÀÇ ½ÂÀÎµÈ ¹èÃâÀåÄ¡ ¼³°è·Î´Â ¾×»ó󸮽ýºÅÛ(liquid barrier mechanism) ¹× ÆÒ¹æ½Ä ȯ±â½Ã½ºÅÛ(fan-driven dilution air system)ÀÌ ÀÖ´Ù. ¾×»óó¸® ½Ã½ºÅÛÀº ¾ÆÁÖ ¼Õ½¬¿î ÇØ°á¹æ¾ÈÀ¸·Î ±â¼úÀûÀ¸·Î »ó´çÈ÷ ¼º¼÷µÇ¾î ÀÖ´Ù.

µå·ÓÆ©ºê(drop tube)¿¡¼­ »ê¼ÒÈ帧ÀÇ ¼Óµµ°¡ »êÈ­Æ©ºê(oxidant tube)¿¡¼­ÀÇ ¹öºí »ó½Â·üº¸´Ù ³·°Ô µÇ¸é ¸ðµç ¼ö¼Ò°¡½º´Â Çѵ¥ ¸ð¾ÆÁ®¼­(trapped) ¼ö¼Ò¹èÃâ¿ë ÆÄÀÌÇÁ¸¦ ÅëÇÏ¿© ¿ÜºÎ·Î ¹èÃâµÈ´Ù. ÀÌ·¯ÇÑ ¹èÃâÀåÄ¡ ½Ã½ºÅÛÀÇ ¿ë·®Àº ´Ù¾çÇÑ ´öÆ® ÆÄÀÌÇÁ °ü°æ¿¡ µû¶ó ÀûÀýÈ÷ ¼³Ä¡°¡ °¡´ÉÇϸç Àüü ½Ã½ºÅÛ Å©±â´Â ¼ö¼Ò ¹ß»ý·®°ú ÀÏÄ¡ÇÑ´Ù. ÀûÀýÇÑ ¼³°è°¡ ÀÌ·ç¾îÁø ½Ã½ºÅÛ¿¡¼­ ¹ß»ýÇÏ´Â ¼ö¼Ò ³óµµ´Â ¼ö¼Ò Æø¹ßÇÏÇѼ±º¸´Ù 25% ³·Àº ¼öÁØÀ» À¯ÁöÇÑ´Ù.

   
¡ã OSG ½Ã½ºÅÛ¿¡¼­ ¼ö¼Ò°¡½º ¹èÃâÀÌ ÀûÀýÇÏ°Ô ÃøÁ¤¡¤¹èÃâµÇ´ÂÁö OSG ½Ã½ºÅÛ Á¦Á¶»ç¿¡ ´ëÇÑ ¹èÃâÀåÄ¡ ¼³°è °Ë»ç°¡ ÀÌ·ç¾îÁ®¾ß ÇÑ´Ù.

     

The main safety concern associated with the electrolytic process of OSG is the production of small amounts of hydrogen gas. Hydrogen gas (H2) can be explosive under certain conditions. The lower explosive limit(LEL) of hydrogen is 4.1 percent by volume in air and the upper explosive limit is 74.2 percent by volume in air. This means that any concentration of hydrogen in air less than 4.1 percent will not explode (too ¡°lean¡± in fuel) and that air containing greater than 74.2 percent hydrogen will not be explosive(too ¡°rich¡± in fuel). Therefore, at concentrations of 4.1 to 74.2 percent, hydrogen is explosive in an oxygen environment.

H2 is the lightest gas with a vapor density of 0.069(relative to that of air taken to be 1.0) and the smallest in molecular size, causing it to seek the highest point in a room or container in a normal room atmosphere. Because this potential fuel source is produced in any electrolytic process, proper venting of hydrogen is mandatory for the safe operation of OSG equipment.

In a proper installation, hydrogen is diluted to nondetectable levels and vented to the atmosphere. Consultants should investigate the hydrogen venting design of OSG manufacturers to verify that the design has been properly tested and verified. Acceptable designs include liquid barrier mechanisms and fan-driven dilution air systems. The liquid barrier system is elegantly designed to provide a simple solution.

As long as the velocity of the oxidant stream in the drop tube is lower than the rate of bubble rise in the oxidant tube, all of the hydrogen gas will be trapped and vented out of the system through the hydrogen vent piping that discharges external to the building. Sizes for the liquid barrier system and the dilution air vent systems are available in a variety of ductwork pipe diameters, and the system size is matched to the H2 generation rates for the selected system. When designed properly, the systems will bring the H2 concentration to less than 25 percent of the lower explosive limit. Manufacturers can provide complete engineering parameters.

 

Àü±âÀû ¾ÈÀü¼º(Electrical Safety)

 

OSG ½Ã½ºÅÛÀ» ¼³Ä¡ÇÒ ¶§ Àü±â·Î ÀÎÇÑ À§Ç輺ÀÌ ÃÖ¼ÒÈ­µÇµµ·Ï Àü±â ¾ÈÀü¼ºÀÌ °ËÅäµÇ¾î¾ß ÇÑ´Ù. »ç¿ëµÇ´Â Àü¾ÐÀº ½Ã½ºÅÛ Å©±â ¹× Á¦Á¶»çº°·Î ¼­·Î ´Ù¸£´Ù. ¿¹¸¦ µé¾î ´ëºÎºÐÀÇ ¼Ò±Ô¸ð OSG ½Ã½ºÅÛÀº Àü¾Ð »óÇÑ°ªÀÌ 40VDC º¸´Ù Àû´Ù. ÀÌ´Â ÀÛ¾÷ÀÚ°¡ ¿ëÀÌÇÏ°Ô Àü±â¼¿ ÀÚü¸¦ Á÷Á¢ ¸¸Áö´Â °ÍÀÌ °¡´ÉÇÏ¸ç ¼ö¸® ½Ã¿¡µµ Àü±â¼îÅ© ¾øÀÌ ¼Õ½±°Ô ÇÒ ¼ö ÀÖ´Ù´Â ÀǹÌÀÌ´Ù.

´ëÇü ½Ã½ºÅÛ¿¡¼­´Â 40VDC ÀÌ»ó Àü¾ÐÀ» °¡Áö´Âµ¥ ÀÌ °æ¿ì ÀϹÝÀûÀ¸·Î Àü±â ÀÎÅÍ·Ï(interlock)À» °¡Áöµµ·Ï ¼³°èµÇ¸ç ¼¿ ¹Ú½º¸¦ °³¹æÇϸé Àü¿øÀÌ ²¨Áö´Â ¹æ½ÄÀÌ´Ù. ´ëºÎºÐÀÇ °íÀü¾Ð¿ë ºÎÇ°µéÀº Â÷ÆóµÇ¾î ÀÖÀ¸¸ç ÀÌµé ºÎÇ°ÀÇ Æ¯º°ÇÑ º¸¼ö¡¤¼ö¸®´Â °ÅÀÇ ÇÊ¿äÇÏÁö ¾Ê´Ù.

 

Basic electrical safety must be followed when working with on-site generators. This is true of all electrical equipment. On-site generators are designed to minimize electrical hazards. The voltage varies depending upon the size and manufacturer of on-site equipment. For example, most small OSG systems are far below the upper limit of 40 volts direct current (VDC). This means that operators can touch the cell, work on the system and perform basic maintenance without the risk of electrical shock. Larger systems may have voltages in excess of 40 VDC, but they are typically designed with an electrical interlock that shuts down the cell when the cell enclosure is opened. All high voltage components are isolated and rarely require maintenance.

 

¾ÈÀü¼º °ËÅä¿¡ ´ëÇÑ Á¾ÇÕ(Safety Summary)

 

ÀûÀýÇÑ ¼ö¼Ò°¡½º ¹èÃâÀåÄ¡ ¹× Àü±â¾ÈÀü ÀåÄ¡¿¡ ´ëÇÑ È¿À²¼ºÀº OSG ½Ã½ºÅÛÀÇ ¾ÈÀü»ç°í À̷¿¡ ÃæºÐÈ÷ ¹Ý¿µµÇ¾î ÀÖÀ¸¸ç, ¿©·¯ Á¦Á¶»ç·ÎºÎÅÍ ¹Ì±¹ ³»¿¡ 6õ¿© °³ ÀÌ»ó ¼³Ä¡µÇ¾î ÀÖ´Ù. ¹Ý¸é¿¡ ¹úÅ© À̼ÛÀÇ Â÷¾Æ¿°¼Ò»êÀº ÀÌ·¯ÇÑ ÃæºÐÇÑ ¾ÈÀü»ó ÀÌ·ÂÀ» °®Áö ¸øÇÏ°í ÀÖ´Ù.

Áï, ÇöÀåÀ¸·Î À̵¿ÇÏ´Â µ¿¾È ¿¹»óÄ¡ ¸øÇÑ ¿°¼Ò ´©Ãâ ¹× Æø¹ßÀÇ °¡´É¼º, ÀúÀåÅÊÅ©·ÎÀÇ ÅõÀÔ, ÀúÀåÅÊÅ© ÀÚüȯ°æ, ÀúÀåµÈ È­Çй°ÁúÀÇ ¼º´ÉÀúÇÏ ¹× ºÐ¹èÀåÄ¡·ÎÀÇ ÀÌ¼Û µî °úÁ¤¿¡¼­ ¹ß»ýµÇ´Â ¿°¼Ò´©Ãâ ¹× Æø¹ß À§Ç輺ÀÌ Ç×»ó Á¸ÀçÇÏ°í ÀÖ´Ù.

¹úÅ© À̼ÛÀÇ Â÷¾Æ¿°¼Ò»êÀº À¯Çع°Áú·Î ºÐ·ùµÇ´Â °í³óµµÀÇ È­Çй°Áú·Î OSG ½Ã½ºÅÛ¿¡¼­º¸´Ù ¾Ï¹ß»ý À¯¹ß¹°ÁúÀÇ Çü¼ºÀÌ ¸¹À¸¸ç ¿°¼Ò°¡½ºº¸´Ùµµ ´õ ¿­¾ÇÇÑ ¾ÈÀü»óÀÇ »ç°íÀÌ·ÂÀ» °¡Áö°í ÀÖ´Ù.

The effectiveness of adequate hydrogen venting systems and electrical safety is reflected in the strong safety record of the OSG industry, with more than 6,000 installed units in the U.S. from many manufacturers.

Delivered hypochlorite cannot claim the same safety record, with the potential for an accidental chlorine release or explosion occurring during transport to the site, transfer to storage tanks, storage, degradation, and delivery to the distribution system.

Delivered sodium hypochlorite is a concentrated chemical with a hazardous classification, a higher potential for formation of cancerous byproducts than OSG, and a worse safety record than chlorine gas, the substance it is replacing.

 

¿îÀü ¹× Á¤ºñº¸¼ö(Operation and Maintenance)

 

¹úÅ© À̼ÛÀÇ Â÷¾Æ¿°¼Ò»ê°ú °ü·ÃµÈ ¿îÀü ¹× Á¤ºñº¸¼ö »çÇ×Àº ¡âpH ¡â¿ë¾×ÀÇ ¾ÈÁ¤¼º ¡â¿°¼Ò»ê¿° ¹ß»ý(chlorate formation) ¡â½ºÄÉÀÏ ¹× ´©Ãâ ¡âÅ»±â(gasification)·Î ºÐ·ùµÈ´Ù. ÇÑÆí, OSG ½Ã½ºÅÛ°ú °ü·ÃµÈ ¿îÀü ¹× Á¤ºñº¸¼ö »çÇ×Àº ¡â¼¿ û¼Ò(cell cleaning) ¡â¼Ò±ÝÀÇ Ç°Áú(salt quality) ¡â½Ã½ºÅÛ ¿î¿µÀÇ ¿ø°Ý ¸ð´ÏÅ͸µÀ¸·Î ºÐ·ùµÈ´Ù. ÀÌ 2°¡Áö ½Ã½ºÅÛÀ» ºñ±³Çϸé OSG ½Ã½ºÅÛÀÇ Á¤ºñº¸¼ö ÀÛ¾÷ÀÌ ¹úÅ© À̼ÛÀÇ ÀÛ¾÷·®º¸´Ù ÀûÀ½À» º¸¿©ÁØ´Ù.

 

Operation and maintenance issues relevant for delivered hypochlorite include pH, solution stability and chlorate formation, scaling and leakage, and gasification. Operation and maintenance topics relevant for OSG include cell cleaning, salt quality and remote monitoring of system operations. Comparison of the two alternatives reflects much less maintenance required with OSG than with delivered hypochlorite.

 

¼ö¼Ò ÀÌ¿Â ³óµµ Áö¼ö(pH)

 

»ý»ê°úÁ¤¿¡¼­ ¿°±â(caustic) ¹°ÁúÀÌ Â÷¾Æ¿°¼Ò»ê ¿ë¾×À» ¾ÈÁ¤È­½ÃÅ°´Â ¸ñÀûÀ¸·Î ÷°¡µÇ¸ç ÀÌ °á°ú ´ëºÎºÐÀÇ »ó¾÷¿ë Â÷¾Æ¿°¼Ò»êÀÇ pH°ªÀº 12¡­13 ¼öÁØÀÌ µÈ´Ù. ÀÌ·¯ÇÑ pHÀÇ ³ôÀº °ªÀº ¿°±âÀÇ È¿°ú¸¦ Áß¼ºÈ­½ÃÅ°·Á´Â ¸ñÀûÀ¸·Î À¯ÀԵǴ ¹°¿¡ »ê¹°ÁúÀÇ Ãß°¡¸¦ ÇÊ¿ä·Î ÇÑ´Ù.

¹Ý¸é OSG ½Ã½ºÅÛ¿¡¼­ Â÷¾Æ¿°¼Ò»êÀÇ pH´Â ¾à 9À̹ǷΠ³óÃàµÈ Â÷¾Æ¿°¼Ò»êº¸´Ù ¿°±â°¡ 1õ¡­1¸¸ ¹è ÀûÀº °ªÀ» °®´Â´Ù. µû¶ó¼­ Ç÷£Æ® ÀÛ¾÷ÀÚµéÀº »ê¹°ÁúÀÇ Ãß°¡ ÁÖÀÔÀ» ¾ïÁ¦ÇÒ ¼ö ÀÖÀ¸¸ç Àû¾îµµ ¸¹Àº ¾çÀ» ÁÙÀÏ ¼ö ÀÖ´Ù.

 

During production, an excess of caustic(base) is added to stabilize the hypochlorite solution, resulting in pH values 12 to 13 for most commercial hypochlorite. This high pH later requires addition of acids to the water being treated in order to neutralize the effect of the caustic.

Since on-site generated hypochlorite has a pH around 9, it is 1,000 to 10,000 times less caustic than concentrated hypochlorite. Plant operators can either eliminate the addition of acid or at least greatly reduce it when using OSG.

 

¿ë¾×ÀÇ ¾ÈÁ¤¼º ¹× ¿°¼Ò»ê¿° ¹ß»ý(Solution Stability and Chlorate Formation)

 

¿°±âÀÇ Ãß°¡¿¡µµ ºÒ±¸ÇÏ°í Â÷¾Æ¿°¼Ò»êÀº »ý»ê°ú µ¿½Ã¿¡ °ð¹Ù·Î È­ÇÐÀûÀ¸·Î ¼º´ÉÀÌ ¶³¾îÁö°Ô µÈ´Ù. ³óÃà»óÅÂÀÇ Â÷¾Æ¿°¼Ò»êÀÇ ¼º´ÉÀúÇÏ´Â »ê¼Ò°¡½º¿Í ¿°¼Ò»ê¿°À» ¹ß»ý½ÃÄÑ ¼Òµ¶ È¿´ÉÀÇ °¨¼Ò¸¦ °¡Á®¿Â´Ù.

 

3OCl- £­ -ClO3- + 2Cl-
OCl- £« OCl- £­ -O2(gas) + 2Cl-

 

Â÷¾Æ¿°¼Ò»ê ³óµµ°¡ ³ôÀ»¼ö·Ï ÀÌ·¯ÇÑ ¼º´ÉÀúÇÏ´Â ´õ »¡¸® ÀÌ·ç¾îÁö¸ç, ´ÏÄÌ ¹× ±¸¸® ¼ººÐÀÌ Á¸ÀçÇÏ¸é ¹ÝÀÀÀº ´õ¿í ´õ »¡¶óÁø´Ù. ¶ÇÇÑ ¿Âµµ°¡ ³ô¾ÆÁö¸é ºÐÇصǴ ºñÀ²ÀÌ ´õ¿í Áõ°¡ÇÑ´Ù. ÀÌ¿¡ µû¶ó ȯ±âÀåÄ¡°¡ ¼³Ä¡µÇÁö ¾ÊÀº Â÷¾Æ¿°¼Ò»ê ÀúÀå °ø°£¿¡¼­´Â ºÐÇصǴ ¹ÝÀÀÀÌ ´õ¿í È°¼ºÈ­µÈ´Ù.

Â÷¾Æ¿°¼Ò»ê ¿ë¾×ÀÇ ¼º´É ÀúÇÏ´Â Ç÷£Æ®ÀÇ ÀÛ¾÷ÀÚ¿¡°Ôµµ ³ª»Û ¿µÇâÀ» ¹ÌÄ£´Ù. µ¿ÀÏÇÑ ¼Òµ¶´É·ÂÀ» °®±â À§ÇÏ¿© ´õ ¸¹Àº Â÷¾Æ¿°¼Ò»ê ¿ë¾×À» ÁÖÀÔÇØ¾ß Çϱ⠶§¹®ÀÌ´Ù. ´ë´Ù¼ö Ç÷£Æ® ÇöÀå¿¡¼­´Â ´ë¿ë·® ¹úÅ© ÀÌ¼ÛµÈ Â÷¾Æ¿°¼Ò»ê ¿ë¾×À» ¾ÈÁ¤È­½ÃÅ°°í Â÷¾Æ¿°¼Ò»ê °ø±Þ ½Ã½ºÅÛÀÇ Á¤È®¼ºÀ» ±âÇϱâ À§ÇÏ¿© ¿ë¾×À» Èñ¼®ÇÏ¿© »ç¿ëÇϰųª ¿°¼Ò»ê¿° ¹ß»ýÀ» ÃÖ¼ÒÈ­ÇÏ´Â ¹æ¹ýÀ» ¼±ÅÃÇÏ°í ÀÖ´Ù.

Èñ¼®ÇÏ´Â °úÁ¤¿¡¼­ ¹ß¿­¹ÝÀÀÀÌ ÀϾ´Â °ÍÀ» ¹æÁöÇϱâ À§ÇØ ½ÅÁßÇÏ°Ô Ã³¸®ÇØ¾ß ÇÑ´Ù. À̸¦ À§ÇØ Â÷¾Æ¿°¼Ò»ê Á¦Á¶¿¡ ¼ø¼öÇÑ Ç°ÁúÀÇ È­ÇÐÁ¦À縦 »ç¿ëÇØ¾ß Çϸç Â÷¾Æ¿°¼Ò»êÀÇ ÀÌ¼Û °ø±Þ ¶óÀο¡ ºñ±Ý¼Ó¼º ¶óÀÌ´×ÀÇ È£½º¸¦ »ç¿ëÇÏ´Â °ÍÀÌ Á¦Ç°ÀÇ ¼ø¼ö¼º ¹× ¾ÈÀü¼º À¯Áö¿¡ ÇʼöÀûÀÌ´Ù.

°íµç(Gorden) ¹Ú»ç ÆÀÀº ¾×»óÇ¥¹éÁ¦ÀÇ ±¸¼º¹°Áú¿¡ µû¸¥ ¿°¼Ò»ê¿° ¹ß»ýºñÀ²À» ¿¬±¸Çß´Ù. 15% FAC ³óµµÀÇ Â÷¾Æ¿°¼Ò»êÀ» °¢°¢ 3ºÐÀÇ 2 ¹× 3ºÐÀÇ 1 ¼öÁØÀ¸·Î Èñ¼®ÇÏ¿© µÎ °¡Áö ´Ù¸¥ ¿ÂµµÁ¶°Ç¿¡¼­ °á°ú¸¦ ÃøÁ¤ÇßÀ¸¸ç, ÃøÁ¤°á°ú ³óµµ°¡ ³ô°í ¿Âµµ°¡ Áõ°¡ÇÒ¼ö·Ï ¿°¼Ò ¼º´ÉÀúÇÏ ºñÀ²Àº ´õ¿í µÎµå·¯ÁüÀ» ¹ß°ßÇß´Ù.

¿°¼Ò»ê¿°ÀÇ ¹ß»ýÀº ÇöÀç ¹Ì±¹ ³»¿¡¼­ ±ÔÁ¦µÇ°í ÀÖÁö´Â ¾ÊÀ¸³ª ¿¬±¸°á°ú¿¡ ÀÇÇϸé À̴ ȯ°æ¿¡ À¯ÇØÇÔÀ» º¸¿©ÁØ´Ù. ±× °á°ú ¸¹Àº ÀÛ¾÷ÀÚµéÀº ¿°¼Ò»ê¿°ÀÇ ¹ß»ýÀ» ÁÙÀÌ·Á´Â ³ë·ÂÀ» ÇÏ°í ÀÖ´Ù. ¸¸¾à Ç÷£Æ®¿¡¼­ Ç¥¹éÁ¦ ¿ë¾× ÀúÀåÀ» À§ÇÏ¿© ÇϳªÀÇ ÅÊÅ©¸¦ »ç¿ëÇÏ°í ÀÖ´Ù¸é ÀÜÁ¸ ¿°¼Ò»ê¿°ÀÇ ³óµµ´Â ÅÊÅ© ³»¿¡¼­ Á¡Â÷ Ä¿Áö°Ô µÉ °ÍÀÌ´Ù. µû¶ó¼­ ÁÖ±âÀûÀ¸·Î ÅÊÅ© ³»ÀÇ Ç÷¯½Ì(flushing) ¹× Ŭ¸®´×(cleaning) ÀÛ¾÷ÀÌ ÇÊ¿äÇÏ´Ù.

¹Ý¸é OSG ¹æ½ÄÀÇ ½Ã½ºÅÛÀº »ç¿ëÀÚ ¿ä±¸°¡ ÀÖÀ» ¶§¸¸ ³·Àº ³óµµ ¼öÁØÀ¸·Î »ý»ê¡¤ÀúÀåÇϸç ÀϹÝÀûÀ¸·Î 24½Ã°£ À̳»¿¡ Àü·® »ç¿ëµÇ¹Ç·Î ¼º´ÉÀúÇÏ Çö»óÀº ¹®Á¦°¡ µÇÁö ¾Ê´Â´Ù. ÇÑ Á¦Á¶»çÀÇ OSG ½Ã½ºÅÛÀº 1ppm(§·/L) ³óµµÀÇ ÁÖÀÔ¿¡ ±ÇÀå ±ÔÁ¦ ¼öÁغ¸´Ù ÈξÀ ³·Àº 33ppb ³óµµÀÇ ¿°¼Ò»ê¿°À» ¹ß»ý½ÃŲ´Ù.


   
 

Even with the addition of caustic, hypochlorite starts chemically degrading shortly after its production. Degradation of concentrated hypochlorite results in the formation of oxygen gas(O2) and chlorate(ClO3-), reducing the disinfection capability of the solution as show in the equations below.

 

3OCl-- -ClO3- + 2Cl-
OCl- + OCl- - -O2(gas) + 2Cl-

 

The more concentrated the hypochlorite, the faster it degrades. The process is further accelerated by the presence of trace transition metals such as nickel and copper. It has also been shown that increasing temperature increases the rate of decomposition. For example, an unventilated hypochlorite storage shed will accelerate the rate of decomposition.

Degradation of the hypochlorite solution adversely affects plant operations since more hypochlorite has to be injected into the line to achieve the same disinfection power. Many sites choose to dilute the delivered hypochlorite to stabilize the solution and enhance accuracy in hypochlorite feed metering systems or to minimize chlorate(ClO3-) formation. The dilution process must be carefully planned and implemented to avoid an uncontrolled exothermic reaction. Using pure chemicals to make the hypochlorite and nonmetallic-lined hoses to transfer the hypochlorite is critical for maintaining product purity and safety.

Gordon et al. studied the rates of liquid bleach decomposition and chlorate(ClO3-) formation. A 15 percent full-strength hypochlorite was diluted by 2/3 and 1/3 and monitored at two different temperatures. The higher the concentration and the hotter the temperature, the more pronounced the chlorine degradation was.

While chlorate formation is not currently regulated in the U.S., studies indicate that it is harmful to the environment. As a result, or perhaps in anticipation of the introduction of a regulatory limit, many operators strive to reduce chlorate production. If a utility uses a single tank to store liquid bleach, a residual chlorate concentration is probably building in the tank. Thus, hypochlorite storage tanks should be periodically flushed and cleaned.

In contrast, on-site generated hypochlorite is produced on demand at a low concentration and is typically used within 24 hours, so degradation is a nonissue. The OSG systems of one manufacturer produce only about 33 parts per billion(ppb) of chlorate for every 1 parts per million(ppm) dose, a level far below even the proposed regulatory limits of concern.

 

½ºÄÉÀÏ ¹× ´©Ãâ(Scaling and Leakage)

 

½Ã½ºÅÛ ³» ¹èÃâ¶óÀο¡ ÀÌ»êȭź¼Ò ¹× Ä®½·ÀÌ Á¸ÀçÇÏ°í pH°¡ 9¸¦ ÃÊ°úÇϸé ÀϹÝÀûÀ¸·Î ½ºÄÉÀÏÀÌ ¹ß»ýµÈ´Ù. »ó¾÷¿ë Â÷¾Æ¿°¼Ò»êÀÇ ³ôÀº pH´Â ź»êÄ®½·(calcium carbonate) ½ºÄÉÀÏ ¹ß»ýÀÇ ¿øÀÎÀÌ µÇ¸ç ½ºÄÉÀÏ ¹ß»ýÀ¸·Î ÆßÇÁ, ¿ª¾ÐÀåÄ¡(backpressure device), ÆÄÀÌÇÎ µî¿¡¼­ À¯Ã¼ È帧ÀÌ ¹æÇظ¦ ¹Þ´Â´Ù.

Ç÷£Æ®¿¡¼­ Â÷¾Æ¿°¼Ò»ê ¿ë¾×À» Èñ¼®ÇÏ¿© »ç¿ëÇÏ´Â °æ¿ì pH°¡ ³ôÀº ±î´ß¿¡ Ä®½· ÁÖÀÔÀ» ¹æÁöÇÏ·Á´Â ¸ñÀûÀ¸·Î ¿¬¼ö ó¸®µÈ ¹°À» »ç¿ëÇØ¾ß ÇÑ´Ù. ¶ÇÇÑ Â÷¾Æ¿°¼Ò»ê ¿ë¾×ÀÇ ³ôÀº pH´Â PVC Á¢ÂøÁ¦¿¡ ÇÔÀ¯µÈ ½Ç¸®ÄÜ ¹°ÁúÀ» ¿ëÇؽÃÅ°±âµµ ÇÑ´Ù. ¹Ý¸é¿¡ OSG ¹æ½ÄÀº pH°ªÀ» 9º¸´Ù ³·Àº ¼öÁØÀ¸·Î À¯Áö½ÃÄÑ ÅºÈ­Ä®½· ½ºÄÉÀÏÀÇ ¹ß»ý, ½Ã½ºÅÛ°£ÀÇ À¯Ã¼ È帧ÀÇ ¹æÇØ ¹× PVC Á¢Âø¸éÀÇ ½Ç¸®ÄÜ ¿ëÇØ µîÀÇ ¹®Á¦°¡ ¹ß»ýµÇÁö ¾Ê´Â´Ù.

 

Scaling commonly forms when carbon dioxide and calcium are present in the system and the pH rises above 9.0. The high pH of commercial hypochlorite is sufficient to cause the formation of calcium carbonate scale, which can plug pumps, backpressure devices and piping, especially at injection points and solution diffusers.

If the facility chooses to dilute the hypochlorite solution, it must use softened water to prevent the further addition of calcium to a high pH environment, exacerbating the buildup of calcium scale. The high pH of the hypochlorite solution also gradually dissolves the silica in standard PVC glue. In contrast, hypochlorite generated on-site has a pH at or below 9, so calcium carbonate scale, clogged equipment and dissolved PVC glue are not concerns.
 
Å»±â(Gasification)
 

´ë¿ë·®À¸·Î À̼۵Ǵ Â÷¾Æ¿°¼Ò»êÀÇ ¼º´É ÀúÇÏ·Î ÀÎÇÑ »ê¼Ò ¹× ¿°¼Ò°¡½ºÀÇ Áö¼ÓÀûÀÎ ¹ß»ýÀº ½Ã½ºÅÛÀÇ ¿î¿µ»ó ¿©·¯ °¡Áö ¹®Á¦ ¹ß»ýÀÇ ¿øÀÎÀÌ µÈ´Ù. ¹Ì±¹ ¿À·¹°ïÁÖÀÇ ÅëÇÕ¿À¼öó¸®Çùȸ´Â »ó¿Â¿¡¼­ ÇÏ·ç¿¡ 1% ºñÀ²·Î »ê¼Ò°¡ ¹ß»ýÇÑ´Ù´Â »ç½ÇÀ» ¾Ë¾Æ³Â´Ù. ÀÌ´Â 100°¶·±ÀÇ Â÷¾Æ¿°¼Ò»ê¿¡¼­ ÇÏ·ç¿¡ ¾à 1°¶·±ÀÇ »ê¼Ò°¡½º°¡ ¹ß»ýÇÑ´Ù´Â °ÍÀ» ÀǹÌÇÑ´Ù.

ÇÑÆí, ´ÏÄÌÀÌ¿ÂÀÇ Á¸Àç´Â ºÐÇظ¦ ÃËÁø½ÃÅ°´Â ¹°Áú·Î ÀÛ¿ëÇÏ¿© »ê¼Ò°¡½º ¹ß»ýÀ» ´õ¿í ¾ÇÈ­½ÃŲ´Ù. °¡½º´Â ÀϹÝÀûÀ¸·Î ³ôÀº À§Ä¡¿¡¼­ ÃàÀûµÇ¸ç ƯÈ÷ ½Ã½ºÅÛÀÌ °£ÇæÀûÀ¸·Î ¿î¿µµÉ ¶§ È帧¿¡ ¹æÇظ¦ ÁØ´Ù. ÀÌ¿¡ ÀÛ¾÷ÀÚµéÀº ³ôÀº À§Ä¡¿¡ ÆÄÀÌÇÁ ¼³Ä¡¸¦ ÀÚÁ¦Çϰųª ÀÛÀº ±¸°æÀÇ ÆÄÀÌÇÁ·Î ±³Ã¼ÇØ¾ß ÇÑ´Ù.

¶ÇÇÑ Â÷¾Æ¿°¼Ò»ê ÀÌ¼Û ½Ã½ºÅÛ¿¡¼­ °¡½º ¹ß»ýÀº ÆßÇÁ, ¹ëºê, ÅÊÅ© ¹× ¹è°üÀçÀÇ °íÀå ¹× °áÇÔÀÇ ¿øÀÎÀÌ µÉ ¼ö ÀÖ´Ù. ÀϺΠÆßÇÁ¿¡¼­´Â ÇÁ¶óÀÓ ¹× °ú¿­(overheat) Ư¼ºÀ» ÀÒ°Ô µÇ¾î ÆßÇÁ ¼±Á¤¿¡ ¾î·Á¿òÀ» ÁÖ´Â °æ¿ìµµ ÀÖ´Ù. ¹ëºêµµ ºÒ·®ÀÌ ¹ß»ýÇÒ ¼ö ÀÖÀ¸¸ç ÀÌ¿¡ °üÇÏ¿© 2°¡Áö °æ¿ì°¡ º¸°íµÇ¾î ÀÖ´Ù.

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The continuous formation of oxygen and chlorine gas because of delivered hypochlorite degradation causes many operational problems. At room temperature, Unified Sewerage Agency in Hillsboro, Oregon, found hypochlorite will generate oxygen at a rate of 1 percent per day. This means that 100 gallons(378L) of hypochlorite will release approximately 1 gallon(3.7L) of oxygen daily. The presence of nickel ion, which appears to catalyze decomposition to produce O2 gas, only worsens the situation. Gas accumulates in high spots and interferes with delivery, especially when the systems are run intermittently. Operators must usually eliminate the raised portions of pipe or replace the lines with smaller diameter piping.

Gas in the hypochlorite delivery system can also cause pump, valve, tank and plumbing failures. Certain types of pumps lose prime or overheat, making it difficult for operators to find pumps that suit their needs for accuracy, capacity and dependability. Valves are also susceptible to failure. In two documented cases, hypochlorite left trapped between two closed valves caused the ball valves to explode.

Several other types of valves have cracked. Finding piping systems resistant to hypochlorite leaks is also difficult because hypochlorite exploits the weaknesses of the piping system. Hypochlorite leaks through most of the mechanical fittings, and glued plastic joints can fail within months.

When system delivery is compromised by gas accumulation, a steady drop in residual occurs. Once the air has passed, the chlorine residual can rise sharply. These inconsistencies in hypochlorite delivery make standardization of disinfection and later processes, such as dechlorination, difficult to predict and time-consuming to monitor. Employee exposure must also be considered. Staff clothing is often bleached or filled with holes due to normal chlorine off-gassing. If an accident occurs, worker consequences may be more severe.

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