There are more than 23, different chemicals and substances that are used in consumer goods and industrial processes in Canada, and more continue to be developed.
Some of these substances are difficult to remove, and can cause significant pollution problems. For more information about emerging contaminants, see Emerging Contaminants or read the article from The Canadian Press called Look at everyday chemicals in water, Ontario told. For more information about pollution sources, including ways in which you can minimize water pollution, see the fact sheet titled Water Pollution.
The Safe Drinking Water Foundation has educational programs that can supplement the information found in this fact sheet. Operation Water Drop looks at the chemical contaminants that are found in water; it is designed for a science class. Operation Water Flow looks at how water is used, where it comes from and how much it costs; it has lessons that are designed for Social Studies, Math, Biology, Chemistry and Science classes.
Operation Water Spirit presents a First Nations perspective of water and the surrounding issues; it is designed for Native Studies or Social Studies classes. Operation Water Health looks at common health issues surrounding drinking water in Canada and around the world and is designed for a Health, Science and Social Studies collaboration.
Operation Water Pollution focuses on how water pollution occurs and how it is cleaned up and has been designed for a Science and Social Studies collaboration. To access more information on these and other educational activities, as well as additional fact sheets, visit the Safe Drinking Water Foundation website at www. Did you know that we have dozens of fact sheets available on our website?
Please help us to continue to provide this vital information for the leaders of today and the leaders of the future! Canadian Council of Ministers of the Environment. February Centers for Disease Control and Prevention. City of Saskatoon.
Drinking Water. Environment Canada. Clean Water - Life Depends on It! Sierra Legal Defence Fund. September November Francy, Donna S. Government of Canada. Water pollution: causes and effects. January Water pollution: erosion and sedimentation. United States Environmental Protection Agency. May Septic Technologies: Background and Technology.
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How do septic systems work? Here are a few things that you can do to care for your septic system: Do not use your drain or toilet as a garbage disposal; avoid putting dental floss, diapers, coffee grounds and paper towel down the drain, as they can clog up your septic system. If wastewater treatment processes can remove nearly all of the harmful substances in wastewater, then how can wastewater pollute drinking water sources?
What about industrial waste? Can public wastewater treatment plants really remove all of those toxic chemicals? Wastewater from commercial and industrial processes is usually divided into the following four categories and dealt with accordingly: 1. I would like to help educate the leaders of today and the leaders of the future! Resources: Canadian Council of Ministers of the Environment. Newer Post Viruses. Older Post Water and Human Health.
Follow us. Email Address. Sign Up. Thank you for signing up to receive Safe Drinking Water Foundation email messages! Send us jokes related to water or science for our Funny Friday posts on Facebook. For example, plants can culture a mass of microbes and pass the waste material over the biofilm. Other plants mix the biomass with waste material, creating activated sludge that can be recycled for reuse. The resulting biological floc removes carbon and nitrogen from organic wastes.
Oxidation can occur on the surface—in lagoons—or in filter beds containing coked coal and limestone. Some facilities construct wetlands and reed beds that decompose organic materials.
Other technologies used include membrane bioreactors and biological aerated filters. The resulting waste water collects and settles in a secondary clarifier tank. The final phase is to treat the remaining water and biosolids, or sludge. Gravity separates organic waste from heavier grit, which can be deposited in a landfill. The remaining primary sludge passes to a thickener, where it is centrifuged and fed to digesting tanks containing anaerobic bacteria.
These tanks produce methane that can be used to power the plant. The final solid product, stabilized sludge, can be partially deodorized and plowed into soil as fertilizer. The remaining waste water is treated to remove phosphorus, nitrogen and other nutrients, disinfected with chlorine, ozone or ultraviolet light and then returned to the water supply. All discharge from and equipment used by waste water treatment plants must meet U.
Environmental Protection Agency standards. He holds an M. The department logs its maintenance in feet per day, and it likes to reach , feet per month if it can, meaning that every pipe in the system gets a look-see once every few years. GIS keeps the maps updated, of course, but Stanley's system has been working since they were using nothing more than blueprints and as-built surveys; finding that what's an 8-inch pipe on the map is really a 6-inch is just part of keeping on top of things.
That's why you carry different-size saw blades in your truck. Stanley says a sewer is a simple thing: The pipe needs to drop about half a foot per feet of length, a slope of 0. Bigger pipes inches or larger--can slope even less. But they all must flow downhill, powered by gravity, which is why sewer pipes so commonly crisscross the stormwater drainages: Raleigh Public Utilities Department director Dale Crisp calls all the sewers that run in a particular drainage a "sewershed," which for a while became my favorite new word.
Of course, if wastewater pipes followed only natural gullies, the mains would eventually have to parallel the river, and for many reasons, from aesthetics to the catastrophic results of a spill, nobody wants that.
The system generally moves downhill, but pipes sometimes need to cross rises. So the city has more than lift stations, where the contents of pipes are pumped to join other flows or where wastewater from lowlying areas collects in sumps. When the water gets high enough, it trips a float valve and a pump clicks on and lifts it up a hill--kind of like your toilet, only this float valve starts the flush instead of stopping it. I visited one lift station, a by foot rectangle of electrical boxes that look like a central air-conditioning system behind chain-link fences between two houses, controlling an underground sump; even when it's pumping, if you were more than 10 feet away you wouldn't hear it.
The station has a backup pump and a generator to power it, plus a little antenna to send information back and forth to the supervisory control and data acquisition SCADA system at the treatment plant; that's plenty of equipment, but just the same, if you weren't looking for it you wouldn't know it was there.
A much larger station sits on the trunk line, giving a lift to pretty much all of Raleigh's waste on its way to the plant. It's underneath a highway on-ramp, and though some people suggested I could find it by following my nose, it didn't smell when I went out to visit it. Stanley hands over a laudatory profile of Raleigh's sewer maintenance department in a recent issue of Municipal Sewer and Water magazine, then hands me off to Robert Smith, a sewer monitoring supervisor and asks him to show me around.
First things first: We walk the yard, checking out trucks. Sewer guys basically do three things: They perform maintenance, they respond to crises, and they "TV" pipes, sending tiny little vehicles with cameras on them up the pipes to check both their condition as part of general maintenance and whether the crews who claim to have recently maintained them have actually done so.
Smith shows off the department's various trucks. Rodder trucks have a spool of linked rods, a sort of long chain that the workers feed into a manhole and then rotate, just like someone cleaning roots or a clog out of your drain at home.
Some rodders have cutting blades or spiral grabbing implements to clear roots or debris. Flushing trucks carry enormous water tanks to feed high-pressure hoses with spinning heads on the end: Workers feed the hose into the system, usually past the next manhole, and then turn on a pump.
Water pressure starts the head spinning, spraying water at thousands of pounds of pressure per square inch back toward the truck as the truck pulls back the hose, scouring the pipes along the way. Standard now is the combination truck, which carries tanks of water for flushing and a garbage-truck-size tank for postflush water, which the truck vacuums up with a huge tube that hangs from a derrick over the cab like an elephant's trunk. The driver eventually empties that tank onto a pad in the parking area, Smith explains; water drains off into the sewer system and the cleaned-out debris--tampons, bricks, gravel, roots, supposedly flushable materials--gets loaded into a dump truck once a week and sent to the landfill.
Smith marshals those vacuum trucks when Raleigh has a sewage overflow, too. Another truck he calls a blockbuster has a water hammer--a pipe that uses water to rhythmically pound and break up large blockages.
Finally, he shows me a sort of souped-up golf cart that provides access to the many parts of the system that, because they follow ravines rather than roads, are not easily reached by regular trucks. But we're standing in a parking lot while people are out in the field, rodding sewers. Our first stop is a highway off-ramp, where two flush trucks and a pickup are parked behind orange cones. Several men wearing hard hats, green mesh vests, and rubber-palmed gloves manage a hose coming off a spool on the back of one of the trucks and running to a manhole 20 feet down a steep ravine.
A hundred yards away, two guys stand at another manhole looking out for the spinning head of the water jet, which Smith says is called a Warthog. Once it's past, the guys still at the truck turn on the jet and the spool to start reeling it back in. Over the roar of the truck engine Smith explains that on the way out the head sprays as a sort of presoak; "on the way back, it's like a broom. It looks like you sprayed foam on that pipe. Where the vacuum trucks can't reach a manhole, the crew flushes debris downstream to one the truck can reach.
That's sewer flushing, and the sanitation department does it all day long. Ever since the Hamburg sewers first captured tidal water and then released it all at once to flush out debris, the basic idea hasn't changed much: You use water to flush, you use rods or hooks to attack clogs, and, as Ed Norton sang, you keep things rolling along. Smith packs us back in his pickup and we drive to a parking lot and a box truck with a picture of a fish on it. The three guys in the truck are going to TV a pipe: Mike is preparing the camera and the screens in the back of the truck while Wayne and someone who introduces himself only as "the Rev" open the manhole, popping the cover off easily with a metal hook.
Wayne and the Rev then retrieve the camera from the truck. With six tiny rubber wheels and an inquisitive single eye, it looks a bit like the Mars rover vehicle, only tiny and dangling at the end of a wire. When they come back to the manhole Wayne and the Rev are shocked to find it suddenly filled with sewage.
This kind of backup indicates a block in the 6-inch pipe at the bottom of the manhole, though it drains away as fast as it backed up. A few moments of observation shows two things: The backup comes and goes rhythmically, meaning there's a pump station upstream that sends a pulse of wastewater every couple of minutes, and the blockage is a bunch of pieces of some solid substance that nobody can identify.
Out come spoons--hooked, perforated shovels on the end of foot handles. Wayne, Robert Smith, and Eddie, another supervisor who has arrived, take turns scooping, pushing things back and forth between rushes from the pump and pulling them out with an awkward hand-over-hand motion that keeps the gunk barely balanced on the edge of the spoon unless you knock the handle against an overhanging tree branch.
It's like using an iced-tea spoon to fish olive pits out of a bleach jug at the back of a cupboard. The stuff turns out to be congealed grease, and pieces of it are sufficiently solid--and sufficiently far up the 6-inch pipe--that they block the progress of the camera every time the Rev dangles it down there and tries to get it running.
The vacuum nozzle can clear the manhole but can't pull grease out of the pipe and it resists everything else they've got, so the crew finally gives up on TV-ing that pipe for the day, until they can clean the pipe--possibly by using a bucket truck which feeds a cable past the debris and drags a bucket from one manhole to the next, pulling before it the kind of grit and large debris flushing just doesn't get or possibly by sending someone down there in the hope that a simple scoop into the pipe will clear the debris.
Sending someone down a manhole, though it's only about 8 feet deep, requires confined spaces training, extra supervision, and ventilation equipment--sewer gas contains methane and hydrogen sulfide, and it has killed workers as recently as Smith shows me video footage from another TV-ing expedition that shows long traverses down shiny pipes half full of dull gray water.
The color makes sense--much more of it comes from your washing machine and shower than from your toilet. Though most blockages are caused by grease or roots, the talk naturally turns to memorable clogs, and I hear about mops, golf clubs, firewood, riprap, and even a refrigerator that have had to be pulled out of manholes. Once a carpet remnant created a block so nasty it took most of a day to clear out.
If you're on call and someone calls in a spill, especially one where the overflow is making its way toward a waterway, then it's showtime. A pump immediately starts channeling the polluted water into the nearest downstream manhole. And while a crew works on clearing the clog itself, other crews chase the spill, hosing down the sides and bottom of the stream. You can tell when untreated wastewater has hit a stream, Smith says, by the powdery-looking buildup it leaves: "It looks like gray dust in the water," coating the rocks and sticks.
The hoses clear the scum off the bottom and stir up the mud. It's pretty neat. One day I pulled over on a main highway to watch a sewer crew fix a leaky pipe using what's called cured-in-place pipe: A long liner impregnated with resin is pushed into a pipe by water, then they pump steam through the pipe to harden the resin, and presto--the pipe is, though slightly narrower, all but new.
The crew runs an auxiliary pipe while they fix the leaky one. Workers can find leaks by stopping up pipes with sandbags, pumping smoke down a manhole, and then seeing where the smoke starts creeping out of the ground. Clearly, people have thought about this stuff a lot. I had stopped by a sewer truck to watch a couple of guys hose out a pipe, which they followed to a manhole at the backyard boundary of a few properties.
Rather than dig on several people's private property, the city decided to abandon the line running between the houses and reroute the flow to the end of the street, where it could join a larger main and head downhill. But since the flow had to go downhill, the engineers had to get wastewater to flow away from the manhole in a different direction. That meant, simply, digging a deeper trench in the direction they wanted it to go. They had to do the same thing on the line that received the new flow, so they were digging on two streets for a few weeks, and I occasionally stopped by.
I watched them carefully lower new green PVC pipes and check the slope. They use a laser to measure, with a sort of bull's-eye target at the end. The red dot right in the center means the pipe has the right slope. A lot easier. Any pipe below 12 feet has to be ductile iron, to support the weight of the earth on top; same with any pipe that crosses a creekbed, hangs under a bridge, or does anything but lie directly on the earth.
Even though sewer pipes start out low and have to keep going lower, in a city with no subway system there's not much other infrastructure in the way; 12 feet is fairly deep for Raleigh. The Neuse River Wastewater Treatment Plant, southeast of Raleigh, discharges most of the plus million gallons of water it treats every day in a state bordering on potable. Spread over acres and surrounded by 1, acres of farm fields for application of biosolids , the plant is big enough that to see it you have to tool around in a van; you can't walk it like you can the water treatment plant miles upstream.
Superintendent T. Lynch started my tour with a drive to the headworks, where screens and vortex filters remove the floating junk and grit from the outflow of the twin inch trunks flowing in from the sewer system. The floating stuff is more obvious, but Lynch emphasizes the basins that settle out grit: In a process heavy on pumps and pipes, grit is anathema. It will literally wear out your equipment. Remarkably, though the air has a certain tang, it doesn't stink.
Outside the headworks Lynch points to a concrete basin almost the exact size and shape of a baseball field, sloping downward from the outfield to a low point at home plate: a million-gallon equalization tank. The sewer system does not have water towers or storage tanks to accommodate regular fluctuations in wastewater volume flow peaks at breakfast time and again just after midnight , so it stores water in the equalization tank during periods of high flow and, especially, storms: Lynch says, "It's not uncommon for us during a heavy rain to see our flow double.
When the flow slows down again, he uses four enormous screw pumps to push the water to the top of the slope on which the plant is built--the rest of the way through the plant, gravity does the work. He shows off the pumps proudly. They're called "vertical turbine solids-handling pumps," but he notes that they use technology roughly unchanged since the time of Archimedes: turning screws to lift water.
From the headworks the water flows to primary clarifiers--tanks through which the wastewater flows extremely slowly, not unlike the settlement basins at the water plant, and with the same goal: allowing solids to settle to the bottom, creating a "primary sludge blanket," though here grease and oil also float to the top.
Scrapers make a circuit along the surface, scooping grease into a small flume, then cycling to the bottom where they shepherd the sludge to its own pumps. Water cleanliness is measured by biochemical oxygen demand BOD --the amount of oxygen the bacteria in the water use to remove its organic impurities. The lower the BOD, the smaller the next basins can be and the lower the plant's operating costs. This is a crucial point, given how much energy the next step takes.
That step is what Lynch calls "the absolute heart and soul" of his plant: the activated sludge process. So after a few hours in the clarification tank, the water flows into aeration basins, six concrete pools of several million gallons apiece, the bottoms of which are crisscrossed by air nozzles.
These enormous tanks of what looks like boiling brown sewage are just what you imagine when you think "sewage treatment. Bacteria in the basins multiply rapidly, like the starter for sourdough bread. The wastewater provides the food, the nozzles provide the oxygen, and the bacteria feel like they're on a cruise: nothing but breathing, eating, and reproducing, with free food all day long. This process removes all the harmful chemicals from the water--except nitrates, which feed algae in rivers.
These algae propagate wildly and then die.
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