Cd'A Wastewater Treatment Plant Tour

hello everyone and welcome to the city of quarter lane waste starter utility department today we're going to be taking a tour of our treatment plant wastewater treatment all begins in our screenings building the first thing we need to do with the incoming wastewater is to screen it for items such as hair toilet paper what we refer to as rags in front of you are two bar screens these bar screens have vertical bars that extend down into the wastewater their purpose is to grab onto any of those long items that you can imagine like the hair or the toilet paper you can see these flights going rising up and down they're actually cleaning those bars we'll take a look on the back side to see what that looks like below the screens you can see a horizontal chute that captures those rags that are screened out once enough rags pile up water will flush the rags down the chute there's some now to our washer and compactor the washer and compactor will actually grind wash and then dry those rags the other item we remove in screenings building is grid grit is all the inorganic rocks and things like that that get into the wastewater stream these are terrible for the process and must be removed before treatment begins the grit is separated and then pumped through these cyclones which helps to dry it sending more water one direction and more of that grit the other inside here is a pretty thick slurry of grit this inclined auger actually helps to dry out the grit and then we deposit it into one of these dumpsters we'll fill up about two of these dumpsters every week of this inorganic grit material after screening the wastewater continues through a flow measuring device and our first sampler we have several of these samplers throughout the plant that sample 24 hours a day so we know everything that's coming into our facility after that is our influence pump station our entire collection system is mostly gravity but at this point we need to begin pumping that upstairs is all of our motor control items including our scada computer downstairs are three influent pumps each one of these pumps can pump about seven million gallons every day we get in approximately three and a half million gallons every day which means we have some redundancy here our peak flows at about 10 am are about 6 million gallons to maybe 7 million gallons whereas at 2 in the morning we're down to about 1 million gallons these pumps will pump that flow down this pipe to our next stage which is here this is our aerated grit removal station the flow gets pumped through this chamber where air is added the air lowers the specific gravity and allows that grit to be separated and then pumped back to where we saw in the screenings building where it gets washed and dried and sent out to the landfill after aerated grit our next station is primary clarifiers this is our first real stage of treatment up until this point we keep the flow moving to keep all solids suspended within it but in the primary clarifiers we actually slow that flow down our influent solids is about 300 milligrams of solids per liter of water once the flow goes through this primary clarifier that effluent water you see around the outside is about 100 milligrams per liter we've settled out about two-thirds of the pollution simply by slowing down the flow but that's all we could get at that point we're going to need to use these pumps to pump the flow up to our trickling filters our trickling filters provide biological treatment and that's the secret sauce that really gets the job done let's have a look inside the trickling filters the arm is being pushed around hydraulically that's actually our waste water it's trickling down through the media plinko style living on that media is our biology as the wastewater trickles pass it it has both oxygen and food which we call it at this point which is the pollution within the wastewater it's going to help get rid of that last remaining 100 milligrams per liter but it's not enough our bugs actually need more contact time than just a trickling filter can provide so we pump it over to here our solids contact tank the solids contact tank consists mostly of bugs at this point coming down towards us they're getting tons of air but no food as begins to leave it circles back wherein we introduce food what do these bugs look like hey john you mind if we take a look thanks these bugs are where they're doing the bulk of the work this is a crawling ciliate it's a single-celled organism that's actually walking on that carbon and phosphorus that we're trying to get rid of these little guys are actually eating and digesting and breaking down all of that pollution up next we've got a stalked ciliate these little guys are quite different in that they physically attach themselves to the mass [Music] you can also see the rotating cilia around its mouth or the bulb he's actually using that to bring the food into his mouth these will quite often grow together in what resembles a bouquet of flowers up next a crowd favorite the rotifer this guy's quite a bit bigger than the others you can see the cilia swirling that mass bringing it closer to its mouth as well as the two spurs that are it's using to anchor itself to that biomass on the left of the screen you can even see what are its intestines about halfway through the body even bigger still the round worm you can see on the front those two false eyes that help it with predation you can also see the undulation of the body as it's moving the material through its intestines and breaking it down you may have noticed some of these guys outside of our treatment plant the artist affectionately referred to them as the cleaning crew back to our solids contact tank all those bugs are in here with the air breaking down those last little bits of food at the end of this chamber we'll split it off into our secondary clarifiers our secondary clarifiers work much like the primary clarifiers only this time we've had biological treatment and can get much better removal this is secondary clarifier number three our newest one the flow from the solids contact tank comes out here in the middle where you can see it's quite a bit darker in color from here it spreads out to the perimeter of the clarifier and in that time it has a chance to settle down to the bottom this clarifier is about 12 feet deep and at the bottom of it is what we call a blanket that blanket consists of all those bugs it's about two or three feet deep the top what's going to go over the edge of the weir is now down to about 5 milligrams per liter of solids so we've removed virtually all the solids at this point although the carbon has been removed we're still not quite done we'll need to remove phosphorus and nitrogen and that happens here at our tertiary membrane facility our tertiary stage of treatment that secondary effluent water is pumped up here where we use biology to remove the ammonia and membranes to remove phosphorus and that last little bit of solids let's have a look inside one of our trains here one of our trains is undergoing maintenance for cleaning gives us an opportunity to look inside to see what these look like you can see it's quite a bit browner again that's due to the biology and the ammonia removal we've just completed cleaning this membrane cassette we're gonna fly it back in place so it can do its work you can see that these membranes are really just fibers held in what we call a cassette these fibers have really small holes 0.04 microns the human hair is about 50 microns in fact bacteria are about 5 microns meaning bacteria aren't even getting past these membranes that's about fifteen thousand square feet of surface area on that one cassette we've got six cassettes in each train there's about two football fields of surface area inside each train there's a pretty stark contrast between the technology of these membranes and our trickling filters there's a whole slew of technology running in the background to make sure that this system operates efficiently we're taking a walk through the motor control center which houses on the left the scada center and on the right the control equipment strictly for this membrane system operators are able to at a glance see everything that's going on in this process outside of this door is our blower gallery there's a lot of air needed for this system the blowers in front of you are scour air blowers these actually run on magnetic bearings magnetic bearings are needed for the speed which great and greatly reduce the friction these blowers are used to provide air for the bacteria that are breaking down the ammonia simple chemicals of citric acid and a strong bleach solution are used to make sure the membranes are foul free there's more equipment downstairs so let's take a look [Music] those three red cones in front of you are strainers they're used to strain all the water that's coming into the membrane system this is important insurance due to the delicate nature of the membranes these are what we term our permeate pumps they're used to draw the water through those membranes that .04 micron sized hole on the other side of the membranes all phosphorus and solid remain and only clear water passes through you can see via turbidity on this meter just how clean the water is we utilize this clean water for processes throughout the plant that includes spraying down foam and cleaning keeping things clean for disinfection purposes we use this uv system this is an important resource for us as you can see we're using about 300 gallons per minute of this water that equals almost half a million gallons every day another key part of this system is our chem scan the chem scan measures orthophostate and ammonia coming into and out of the tmf which measures the productivity and the effectiveness of the system after the water passes through the membranes it flows downhill to our chlorine contact tank we use chlorine as a disinfectant agent recall that most of the bacteria is removed by the membranes themselves but viruses can still persist chlorination followed by a sulfur dioxide for dechlorination ensures our product is clean and safe to be placed into the river of course prior to discharge we do final sampling to make sure our process worked [Music] so now we've seen what happens to the water how clean we can get it but what about the solids that settle on the bottom of this clarifier well they head into this room [Music] the solids if you remember are microorganisms or what we call bugs we like the bugs to do more work so we send many of them back to the system to eat more of the influent wastewater that's what the pumps in front of you are doing those are return pumps those bugs circle around and around for about three days but if we get too many we have to waste it and that's what this pump does we waste to a digester an anaerobic digester which has no oxygen in it i know you're curious to see what it looks like what do these bugs look like let's have a look i'll show you and this sink is what we use to sample from so if i open this valve up a little bit it's not as thick as you might think but that's about one percent solids or 10 000 milligrams per liter these hose pumps are used to pump the solids that settled in the primary clarifier system as well all of these are heading to the anaerobic digester to save room in the digester we thicken up the sludge before it enters it left the clarifiers at about one percent solids in this tank is where it got pumped gets mixed with a polymer where it sticks together you could see it clumping in there as it exits this rotary screen thickener it's closer to about five percent solids so again we're separating the water from the solid portion of wastewater throughout the entire process after our sludge is thickened it gets pumped into this large tank anaerobic digester number five the solids will spend about 30 days inside this tank where there is no oxygen bacteria literally rips open cells to get oxygen this is an important step in the process to ensuring that the solid portion is safe for handling a byproduct of this process is what we call biogas biogas contains about 55 methane we utilize this methane gas for other parts of the process specifically heating things up these are our two boilers we can run on digester gas or natural gas heating up this water is an important process as the bugs in a digester like it at 100 degrees fahrenheit which isn't always easy to achieve when it's quite cold outside you can see the extensive network of hot water piping in this video every pipe in white is insulated hot water line in this section it's being pumped through this heat exchanger hot water goes in one channel and the sludge from the digester gets pumped through the other and maintains that toasty 100 degrees inside our digester on the other side of this wall while we're down here let's take a trip down our pipe gallery [Music] [Music] as you can see that hot water piping spreads throughout the plant we use it not just for heating anaerobic digester number five but also up here anaerobic digesters three and four it's also used to heat every building that's occupied by people this saves us a significant amount of energy have you ever been running down this trail if you have you may have noticed our flare that flare is used to burn off any excess gas because of the high methane content we burn this gas rather than releasing it after about 30 days in the anaerobic digester our solids are ready to be sent out to compost but prior to that they run through the centrifuge this centrifuge dries the solids to about 25 percent the water you can see spilling on the bottom is sent back to the plant for further treatment here's our control panel that we use to operate do you want to see what it looks like on the way out come on i'll show you we fill up about two truckloads of solids every day of the week here's what it looks like on the way out from here the next stop is compost thank you for taking this tour of the city of quarter lanes wastewater treatment plant

Channel: City of Coeur d'Alene

Views: 17,906

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Id: GUBRRXzYXpI

Length: 20min 41sec (1241 seconds)

Published: Thu Jul 09 2020