advantages<\/strong><\/h3>\nwell, it’s a well-established technology, and quite honestly, i have great faith in its ability to do the work. even when your plant isn’t running very well and your effluent looks terrible, and uv could never do the job. chlorine can do the job. normally you might feed two milligrams per liter, but if it won’t make the requirement at two, okay, we can feed 10, whatever it takes.<\/p>\n
it’s a very effective disinfectant. it’s easy to maintain, and most of us know how to do that because we do it on the waterside as well. we could make a combined chlorine residual if we want. there are just a lot of advantages to that method.<\/p>\n
the availability of the chemical system for other uses, such as we talked about earlier, odor control, that’s also a nice advantage if you already have chloride on the site.<\/p>\n
in addition to this, the advantage of chlorine we set is relatively inexpensive. well, sort of. the cost of the chlorine is inexpensive, the cost of the equipment is inexpensive, and the cost of the concrete tank is quite expensive. you have multiple options, too, with chlorine. you can get calcium, hypochlorite sodium, hypochlorite chlorine gas on and on and on.<\/p>\n
disadvantages<\/strong><\/h3>\nnow, most people would say, well, yeah, but there are some disadvantages to this too, and they’re correct. chlorine is a hazardous chemical, and it can be a threat to plant workers and the 世界杯足球比赛预选赛
. so that is a problem. it takes a relatively long contact time to be effective, as you can see by the size of those concrete tanks. the important part also is the formation potentially of trihalomethanes and other disinfection byproducts. it also tends to release volatile organic compounds from chlorine contact basins.<\/p>\n
back to the iron, magnesium, manganese, and things like that. the chlorine will tend to oxidize these chemicals, and when that happens, it does consume your disinfectant. and again, we talked about how everyone probably has iron in their water in some form. the tds of the effluent treated is often increased by chlorine systems. the chloride content is also often increased, and that is a problem for a number of people who have chloride limits in their affluent permit. so, things aren’t always perfect.<\/p>\n
dechlorination wastewater disinfection systems (30:09)<\/strong><\/h2>\ngenerally, if a chlorine system is used, you’re always going to have to do dechlorination. dechlorination must be provided to make sure that we’re not putting chlorine out into the receiving stream. decloric chemicals have to be rapidly mixed with the effluent in order to be effective. sulfur dioxide dechlorination systems shall be designed with the same equipment as the chlorine systems for maximum interchangeability. i always found that one to be kind of interesting, and most states have that. oftentimes we need effluent reiteration after dechlor because we’ve taken apart the dissolved oxygen in some cases and need to ensure that it has been returned. we also need to monitor the effluent residual to make sure that we meet the discharge permit requirements.<\/p>\n
dechlor is required by most all npds permits, which are ultimately overseen by the epa, so it really doesn’t matter which state you’re in. generally speaking, dechlor can be easily accomplished with the addition of sulfur chemicals like sodium bisulfite, sodium metabisulfite, and sulfur dioxide.<\/p>\n
ozone wastewater disinfection systems (31:12)<\/strong><\/h2>\nso a much less popular chemical disinfection system is ozone. there are a few ozone systems around. it seems like oftentimes, they were much more popular back in the 1970s than they are today. although that’s a pretty generalized statement, i think that’s fairly true. so key iowa design requirements, again, common with many other states, the ozone is not that different from chlorine gas. it’s produced on-site. and then it’s put in solution on that site. and you’re going to note a lot of things here that are very similar. you notice that it takes a long and large concrete contact tank. again, the baffled length is a 40-1 ratio. remember that from the chlorine side? same thing. duplicate tanks are required, same as chlorine. so, we really didn’t change anything between those two chemicals.<\/p>\n