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| |  Posted 1/16/2006 6:56:01 PM | |
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| Recently my wastewater plant coducted a series of air analyses from our on site scrubber units. The results indicated a combination of both mercaptans and hydrogen sulfide. I have been trying to collect information on the effects of hydrogen peroxide addition to belt filter press influent however this seems to be an infrequently used chemical. Can anyone give me an idea of what I might be looking at as far as dewatering interferance with Polymers and lime stabilization?  |
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| | | Posted 5/31/2006 10:42:22 AM | |
| Supreme Being
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| The use of peroxide probably would not adversely impact the sludge thickening operation. It is used sparingly (not very often) because cheaper options are available - ie, chlorine, lime, etc.
Jeff Naumann
(310) 540-0045
FAX (310) 540-0337
http://www.jeffnaumannassociates.com/ |
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| | | Posted 6/5/2006 4:18:09 PM | |
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| H2O2 is one of the five primary chemicals used for sulfide control in the municipal wastewater industry (the others being iron salts, chlorine/hypochlorite, nitrates, and permanganates). As a result of e.g., chlorine replacement in pulp bleaching, H2O2 use has grown over the past 25 years as its production capacity has grown > 5x and its (inflation adjusted) price has decreased 70-80% while those of iron salts have more than doubled. That said, H2O2 use for solids odor control is not as widespread as permanganate and iron salts, for the following reasons:
1) The H2O2-Sulfide reaction in solids slurries typically takes 3-10 minutes to reach 90% completion (after complete mixing). Such holding times are not always available before a dewatering process;
2) H2O2 reactivity toward mercaptans is much less than e.g., permanganate or chlorite, and so 'organic' odors typically remain even though H2S levels are lowered. These organic odors can be 'bioremediated' by adding the H2O2 to a sludge holding tank within 15 - 45 minutes prior to dewatering - the H2O2 provides D.O. for biomediated oxidation of the mercaptan odors - though again this is not always practical;
3) H2O2 provides little in the way of durational control of sulfide. This is in contrast to iron salts that can be added to digester influents, with sulfide control extending to the dewatering operation. To a lesser extent than sulfide, iron salts will bind to mercaptans to reduce their emission.
There are, however, situations where these constraints are not limiting in which cases H2O2 addition is cost-effective. I can provide you with a list of several such reference facilities if you wish, as well as a test procedure to compare / estimate chemical use. Please e-mail me directly.
Regarding interference with dewatering polymers (there’s no impact on lime stabilization), gross overdosing (e.g., by > 5x the H2O2 requirement) may impact dewatering by supersaturating the solids slurry with entrained oxygen, but there’s no significant chemical reaction between H2O2 and traditional polyacrylamides under normal circumstances. On the contrary, if significant levels of Fe2+ are present (from e.g., Fe addition to digesters) then the sulfide oxidation reaction can take place much faster and in the process hydrous ferric oxide can be produced, resulting in improved coagulation and/or reduced polymer demands.
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| | | Posted 1/13/2007 8:28:47 PM | |
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| | My hometown plant has a bad odor problem. They blame it on industry. Hydrogen Sulfide is their reasons given. They are thinking of using peroxide at three of the industries. I think they are wrong. I found a town here in Ohio that uses Calcium Nitrate in their collection system, mainly at the lift stations. If anyone has information regarding this method let me know. Our main problem is the odor from the plant bothering a retail establishment that is about 300 yards downwind from the plant. There are approx. 30 stores and eating establishments inthis downwind area(Walmart, Loews, Appelbees, Burger King, IHOP, just to name a few). We recently completed a $35 million expansion/upgrade. The odors started after it was completed. |
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| | | Posted 1/14/2007 4:43:47 PM | |
| Supreme Being
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| | I assume you have an Activated Sludge type treatment plant. If you do, submerge your influent pipe outlet to about one, or one and a half feet from the bottom of your aeration basin. In most cases it will eliminate or reduce the odors to acceptable levels. The activated sludge will absorb all or most of the H2S and other odourous chemicals in suspension. As a polisher, you can cover the aeration basins. If your odors are coming from your sludge handling facilities, then this is a different animal. |
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| | | Posted 1/14/2007 5:08:10 PM | |
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| | Ron: There was an article entitled "Hydrogen Sulfide Odor Control in Wastewater Collection Systems", by Peter Churchill and David Elmer, Vol. 33, No. 1, pp 57-63, and published in the May 1999 issue of NEWEA Journal. You can probably still download it for free from New England Water Environment Association website newea.org and download it using the following link: http://www.newea.org/download.htm The PDF is about 2.28 Megs in size. It is an excellent FREE journal and it packed with a lot of excellent information. Thanks to NEWEA for providing this excellent free resource!
E. coli happens! Database Central 
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| | | Posted 1/14/2007 9:26:47 PM | |
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| | I work at an 15 mgd activated sludge plant and we use a chemical (VX456 trade name) sodium nitrate/sodium chlorite solution to control H2S in our gravity belt building. We inject it about 30 feet before it sludge hits the belt. VX456 is designed to attack sulfide compounds, and does not oxidize ammonium nitrogen which is a concern if you land apply the sludge. The draw back is that the chemical is very expensive. I am interested if anyone uses sodium hypochlorite for am application similar to mine. Nick |
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| | | Posted 1/16/2007 5:56:32 PM | |
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| | Hypochlorite could potentially oxidize some of your ammonium and also decreases the dewaterability of the sludge. It breaks down the sticky coating on the cells which decreases its dewatering characteristics and could cause you to increase your polymer to account for it. VX 456 is sodium chlorite, which works well since it will not oxidize ammonium. If you can find a cheaper source of this chemical you could save some money. I would try iron salts, since they react with sulfide well (down to about 0.1 mg/l) and increase the dewaterability of the sludge. If you do this, I would sent the filtrate back to the head of the plant to get some benefit from the residual iron. Permanganate also generally improves the dewaterability of the sludge but is expensive, difficult to handle/mix and will oxidize ammonium. |
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| | | Posted 1/16/2007 6:25:17 PM | |
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| | We use a product called Bioxide. It is like a nitrate fertilizer. It is very concentrated and will burn vegetation at full strength. Anyways it works very well for us. We introduce it at a station in the collection system and by the time it reaches our headworks the smell is reduced significantly. It is made by US filter. We use about 65 gallons per day in the summer and 25 per day in the winter. We've used as much as 100 gallons per day. It just depends. |
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| | | Posted 5/10/2007 2:23:40 PM | |
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| Does it cost-effective applies H2O2 directly to an effluent with a high organic charge content and very high grease content (because of here is important the fishery industry) to achieve odor control in the collection system? or you should applies it after a primary treatment in the treatment plant and use another technologies for the collection system odor control? The effluent just before entering to the plat is about 300mg/L:BOD and total flow about 3m3/seg)
Paula |
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