Category Archives: water

The straight flush

I’m not the wildest libertarian, but I’d like to see states rights extended to Michigan’s toilets and showers. Some twenty years ago, the federal government mandated that the maximum toilet flush volume could be only 1.6 gallons, the same as Canada. They also mandated a maximum shower-flow law, memorialized in this Seinfeld episode. Like the characters in those shows, I think this is government over-reach of states rights covered by the 10th amendment. As I understand it, the only powers of the federal government over states are in areas specifically in the constitution, in areas of civil rights (the 13th Amendment), or in areas of restraint of trade (the 14th Amendment). None of that applies here, IMHO. It seems to me that the states should be able to determine their own flush and shower volumes.

If your toilet clogs often, you might want to use more flush water, or at least a different brand of toilet paper.

There is a good reason for allowing larger flushes, too in a state with lots of water. People whose toilets have long, older pipe runs find that there is insufficient flow to carry their stuff to the city mains. Their older pipes were designed to work with 3.5 gallon flushes. When you flush with only 1.6 gallons, the waste only goes part way down and eventually you get a clog. It’s an issue known to every plumber – one that goes away with more flush volume.

Given my choice, I’d like to change the flush law through the legislature, perhaps following a test case in the Supreme court. Similar legislation is in progress with marijuana decriminalization, but perhaps it’s too much to ask folks to risk imprisonment for a better shower or flush. Unless one of my readers feels like violating the federal law to become the test case, I can suggest some things you can do immediately. When it comes to your shower, you’ll find you can modify the flow by buying a model with a flow restrictor and “ahem” accidentally losing the restrictor. When it comes to your toilet, I don’t recommend buying an older, larger tank. Those old tanks look old. A simpler method is to find a new flush cistern with a larger drain hole and flapper. The drain hole and flapper in most toilet tanks is only 2″ in diameter, but some have a full 3″ hole and valve. Bigger hole, more flush power. Perfectly legal. And then there’s the poor-man solution: keep a bucket or washing cup nearby. If the flush looks problematic, pour the extra water in to help the stuff go down. It works.

A washing cup. An extra liter for those difficult flushes.

Aside from these suggestions, if you have clog trouble, you should make sure to use only toilet paper, and not facial tissues or flushable wipes. If you do use these alternatives, only use one sheet at a flush, and the rest TP, and make sure your brand of wipe is really flushable. Given my choice, I would like see folks in Michigan have freedom of the flush. Let them install a larger tank if they like: 2 gallons, or 2.5; and I’d like to see them able to use Newman’s Serbian shower heads too, if it suits them. What do you folks think?

Dr. Robert E. Buxbaum, November 3, 2016. I’m running for Oakland county MI water resources commissioner. I’m for protecting our water supply, for better sewage treatment, and small wetlands for flood control. Among my less-normative views, I’ve also suggested changing the state bird to the turkey, and ending daylight savings time.

Most flushable wipes aren’t flushable.

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I’m a chemical engineer running for Oakland county water resources commissioner, and as the main job of the office is sewage, and as I’ve already written on the chemistry, I thought I might write about an aspect of the engineering. Specifically about toilet paper. Toilet paper is a remarkable product: it’s paper, compact and low in cost; strong enough to clean you, smooth on your bum, and beyond that, it will disintegrate in turbulent water so it doesn’t clog pipes. The trick to TP’s dry strength and wet-weakness, is that the paper pulp, wood cellulose, is pounded very thin, yet cast fluffy. For extra softness, the paper is typically coated with aloe or similar. Sorry to say, the same recipe does not work for wet-wipes, paper towels or kleenex (facial tissues); all of these products must have wet-strength, and this can cause problems with sewer clogs.

Patent 117355 for perforated toilet paper claimed it as an improved wrapping paper.

Patent 117,355 for perforated toilet paper on a roll. It’s claimed as an improved wrapping paper.

Before there was toilet paper, the world was a much sadder, and smellier place. Much of the world used sticks, stones, leaves, or corn cobs, and none of these did a particularly thorough job. Besides, none of these is particularly smooth, or particularly disposable, nor did it fall apart — not that most folks had indoor plumbing. Some rich Romans had plumbing, and these cleaned themselves with a small sponge on the end of a stick. They dipped the sponge end in water for each use. It was disgusting, but didn’t clog the pipes. I’ve seen this in use on a trip to Turkey 25 years ago — not in actual use, but the stick and sponge was there in a smelly bucket next to the hole in the ground that served as the commode.

The first reasonably modern toilet was invented in 1775 by Alexander Cummings, and by 1852 the first public flush toilets were available. The design looked pretty much like it looks today and the cost was 1¢. You got a towel and a shoe-shine too for that penny, but there was no toilet paper as such. Presumably one used a Roman sponge or some ordinary, standard paper. A popular wipe, back in the day was the Sears-Roebuck catalog. It came free to most homes and included a convenient hole in the corner allowing one to hang it in and outhouse or near the commode. It was rough on the bum, and didn’t fall apart. My guess is that it clogged the pipes too, for those who used it with flush toilets. The first toilet-specific paper wasn’t invented till 1859. Joseph Gayetty, an American, patented a product from pulverized hemp, a relatively soft fiber, softened further with aloe. This paper was softer than standard, and had less tendency to clog pipes.

Toilet paper is either touted to be soft or strong; Modern Charmin touts wet strength, while Cottonelle touts completeness of wipe: ‘go commando.”

The next great innovation was to make toilet paper as a perforated product on a roll. These novelties appear as US Patent #117,355 awarded to Seth Wheeler of Albany, NY 25 July 1871 (Wheeler also invented the classic roll toilet paper dispenser). Much of the sales pitch was that a cleaner bum would prevent the spread of cholera, typhoid, and other plagues and that is a legitimate claim. As the market expanded, advertising followed. Some early brands touted their softness, others their strength. Facial tissues, e.g. Kleenex, were sold specifically as a soft TP-like product that does not fall apart when wet. Sorry to say, this tends to go along with clogged toilets; do not flush more than one kleenex down at a flush. Kleenex is made with the same short fibers and aloe as toilet paper, but it contains binders (glue) to give it wet-strength. My guess is that Charmin is made the same way and that it isn’t great on your plumbing.

Paper towels and most baby wipes are worse to flush than Kleenex. They are made with lots of binder and they really don’t fall apart in water. Paper towels should never be flushed, and neither should most baby wipes, even brands that claim to be ‘flushable.” When flushed, these items tend to soak up fat and become fat bergs – the bane of sewer workers everywhere. There is a class action law suit against flushable wipe companies, and New York City is pursuing legislation to prevent them from claiming to be flushable. Still, as with everything, there are better and worse moist-wipe options. “Cottonelle” brand by Kleenex, and Scott flushable wipes are the best currently. In a day or less they will dissolve in water. These products are made with binders like kleenex, but the binder glue is a type that dissolves in any significant amount of water. As a result, these brands fall apart eventually. For now, these are the only flushable brands I’d recommend flushing, and even then I suggest you only flush one at a time. In tests by Consumer Reports, other brands, e.g. Charmin and Equate flushable wipes do not dissolve. These manufacturers either have not quite figured out how to make dissolvable binders, or they can’t get around Kleenex’s patents.

Robert Buxbaum. October 10, 2016. If you live in Oakland County, MI, vote for me for water commissioner. Here’s my web-site with other useful essays. I should mention Thomas Crapper, too. He invented the push-button flush and made some innovations in the water cistern, and he manufactured high-end commodes for Parliament and the royal family, but he’s irrelevant to the story here.

just water over the dam

The chemistry of sewage treatment

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The first thing to know about sewage is that it’s mostly water and only about 250 ppm solids. That is, if you boiled down a pot of sewage, only about 1/40 of 1% of it would remain as solids at the bottom of the pot. There would be some dried poop, some bits of lint and soap, the remains of potato peelings… Mostly, the sewage is water, and mostly it would have boiled away. The second thing to know, is that the solids, the bio-solids, are a lot like soil but better: more valuable, brown gold if used right. While our county mostly burns and landfills the solids remnant of our treated sewage, the wiser choice would be to convert it to fertilizer. Here is a comparison between the composition of soil and bio-solids.

The composition of soil and the composition of bio-solid waste. biosolids are like soil, just better.

Most of Oakland’s sewage goes to Detroit where they mostly dry and burn it, and land fill the rest. These processes are expensive and engineering- problematic. It takes a lot of energy to dry these solids to the point where they burn (they’re like really wet wood), and even then they don’t burn nicely. As shown above, the biosolids contain lots of sulfur and that makes combustion smelly. They also contain nitrate, and that makes combustion dangerous. It’s sort of like burning natural gun powder.

The preferred solution is partial combustion (oxidation) at room temperature by bacteria followed by conversion to fertilizer. In Detroit we do this first stage of treatment, the slow partial combustion by bacteria. Consider glucose, a typical carbohydrate,

-HCOH- + O₂–> CO₂+ H₂O. ∆G°= -114.6 kcal/mol.

The value of ∆G°, is relevant as a determinate of whether the reaction will proceed. A negative value of ∆G°, as above, indicates that the reaction can progress substantially to completion at standard conditions of 25°C and 1 atm pressure. In a sewage plant, many different carbohydrates are treated by many different bacteria (amoebae, paramnesia, and lactobacilli), and the temperature is slightly cooler than room, about 10-15°C, but this value of ∆G° suggests that near total biological oxidation is possible.

The Detroit plant, like most others, do this biological oxidation treatment using either large stirred tanks, of million gallon volume or so, or in flow reactors with a large fraction of cellular-material returning as recycle. Recycle is needed also in the stirred tank process because of the low solid content. The reaction is approximately first order in oxygen, carbohydrate, and bacteria. Thus a 50% cell recycle more or less doubles the speed of the reaction. Air is typically bubbled through the reactor to provide the oxygen, but in Detroit, pure oxygen is used. About half the organic carbon is oxidized and the remainder is sent to a settling pond. The decant (top) water is sent for “polishing” and dumped in the river, while the goop (the bottom) is currently dried for burning or carted off for landfill. The Holly, MI sewage plant uses a heterogeneous reactors for the oxidation: a trickle bed followed by a rotating disk contractor. These have higher bio-content and thus lower area demands and separation costs, but there is a somewhat higher capital cost.

A major component of bio-solids is nitrogen. Much of this in enters the form of urea, NH2-CO-NH2. In an oxidizing environment, bacteria turns the urea and other nitrogen compounds into nitrate. Consider the reaction the presence of washing soda, Na2CO3. The urea is turned into nitrate, a product suitable for gun powder manufacture. The value of ∆G° is negative, and the reaction is highly favorable.

NH2-CO-NH2 + Na2CO3 + 4 O2 –> 2 Na(NO3) + 2 CO2 + 2 H2O. ∆G° = -177.5 kcal/mol

The mixture of nitrates and dry bio-solids is highly flammable, and there was recently a fire in the Detroit biosolids dryer. If we wished to make fertilizer, we’d probably want to replace the drier with a further stage of bio-treatment. In Wisconsin, and on a smaller scale in Oakland MI, biosolids are treated by higher temperature (thermophilic) bacteria in the absence of air, that is anaerobically. Anaerobic digestion produces hydrogen and methane, and produces highly useful forms of organic carbon.

2 (-HCOH-) –> CO₂+ CH₄∆G° = -33.7 Kcal/mol

3 (-HCOH-) + H2O –> -CH2COOH + CO2 + 2 1/2 H2 ∆G° = -21.9 kcal/mol

In a well-designed plant, the methane is recovered to provide heat to the plant, and sometimes to generate power. In Wisconsin, enough methane is produced to cook the fertilizer to sterilization. The product is called “Milorganite” as much of it comes from Milwaukee and much of the nitrate is bound to organics.

Egg-shaped, anaerobic biosolid digestors, Singapore.

The hydrogen could be recovered too, but typically reacts further within the anaerobic digester. Typically it will reduce the iron oxide in the biosolids from the brown, ferric form, Fe2O3, to black FeO. In a reducing atmosphere,

Fe2O3 + H2 –> 2 FeO + H2O.

Fe2O3 is the reason leaves turn brown in the fall and is the reason that most poop is brown. FeO is the reason that composted soil is typically black. You’ll notice that swamps are filled with black goo, that’s because of a lack of oxygen at the bottom. Sulphate and phosphorous can be bound to ferrous iron and this is good for fertilizer. Generally you want the reduction reactions to go no further.

Weir dam on the river dour. Used to manage floods, increase residence time, and oxygenate the flow.

Weir dam on the river Dour in Scotland. Dams of this type increase residence time, and oxygenate the flow. They’re good for fish, pollution, and flooding.

When allowed to continue, the hydrogen produced by anaerobic digestion begins to reduce sulfate to H2S.

NaSO4 + 4.5 H2 –> NaOH + 3H2O + H2S.

I’m running for Oakland county, MI water commissioner, and one of my aims is to stop wasting our biosolids. Oakland produces nearly 1000,000 pounds of dry biosolids per day. This is either a blessing or a curse depending on how we use it.

Another issue, Oakland county dumps unpasteurized, smelly black goo into Lake St. Clair every other week, whenever it rains more than one inch. I’d like to stop this by separating the storm and “sanitary” sewage. There is a capital cost, but it can save money because we’d no longer have to pay to treat our rainwater at the Detroit sewage plant. To clean the storm runoff, I’d use mini wetlands and weir dams to increase residence time and provide oxygen. Done right, it would look beautiful and would avoid the flash floods. It should also bring natural fish back to the Clinton River.

Robert Buxbaum, May 24 – Sept. 15, 2016 Thermodynamics plays a big role in my posts. You can show that, when the global ∆G is negative, there is an increase in the entropy of the universe.

Weir dams to slow the flow and save our lakes

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As part of explaining why I want to add weir dams to the Red Run drain, and some other of our Oakland county drains, I posed the following math/ engineering problem: if a weir dam is used to double the depth of water in a drain, show that this increases the residence time by a factor of 2.8 and reduces the flow speed by 1/2.8. Here is my solution.

A series of weir dams on Blackman Stream, Maine. Mine would be about as tall, but somewhat further apart.

A series of weir dams on Blackman Stream, Maine. Mine would be about as tall, but wider and further apart. The dams provide oxygenation and hold back sludge.

Let’s assume the shape of the bottom of the drain is a parabola, e.g. y = x², and that the dams are spaced far enough apart that their volume is small compared to the volume of water. We now use integral calculus to calculate how the volume of water per mile, V is affected by water height: V =2XY- ∫ y dx = 2XY- 2/3 X³ = 4/3 Y√Y. Here, capital Y is the height of water in the drain, and capital X is the horizontal distance of the water edge from the drain centerline. For a parabolic-bottomed drain, if you double the height Y, you increase the volume of water per mile by 2√2. That’s 2.83, or about 2.8 once you assume some volume to the dams.

To find how this affects residence time and velocity, note that the dam does not affect the volumetric flow rate, Q (gallons per hour). If we measure V in gallons per mile of drain, we find that the residence time per mile of drain (hours) is V/Q and that the speed (miles per hour) is Q/V. Increasing V by 2.8 increases the residence time by 2.8 and decreases the speed to 1/2.8 of its former value.

Why is this important? Decreasing the flow speed by even a little decreases the soil erosion by a lot. The hydrodynamic lift pressure on rocks or soil is proportional to flow speed-squared. Also, the more residence time and the more oxygen in the water, the more bio-remediation takes place in the drain. The dams slow the flow and promote oxygenation by the splashing over the weirs. Cells, bugs and fish do the rest; e.g. -HCOH- + O₂ –> CO₂ + H₂O. Without oxygen, the fish die of suffocation, and this is a problem we’re already seeing in Lake St. Clair. Adding a dam saves the fish and turns the run into a living waterway instead of a smelly sewer. Of course, more is needed to take care of really major flood-rains. If all we provide is a weir, the water will rise far over the top, and the run will erode no better (or worse) than it did before. To reduce the speed during those major flood events, I would like to add a low bicycle path and some flood-zone picnic areas: just what you’d see on Michigan State’s campus, by the river.

Dr. Robert E. Buxbaum, May 12, 2016. I’d also like to daylight some rivers, and separate our storm and toilet sewage, but those are longer-term projects. Elect me water commissioner.

A run runs through it

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The word ‘run’ appears to be a Michigan dialect for small river. Perhaps Michigan’s most famous run is the Willow run, where the airport is. Currently, almost all of our runs are unrecognizable, they are either trapped in pipes underground, or so dredged out and poisoned that they are more properly called sewers. If I’m elected Oakland county water resources commissioner (drain commissioner) I’d like to free some of these runs, and detoxify them.

These branches of the red run flow beneath the surface of Royal Oak with the main section beneath Vinsetta Blvd.

Consider this historical map of Royal Oak. It shows two river branches, currently under ground. Back in the day, these were known as the north and south branch of the Red run. The south branch is fed by the Washington creek and the small run, now under ground, with the main branch of the run crossing Woodward ave at Catalpa st. These runs only appear above ground in Warren, MI, miles away, as a polluted sewer. But in Royal Oak they should still be clean. If they were partially freed. That is if the channel were exposed to air again to provide small wetlands along the original path — along Vinsetta Blvd, for example. Vinsetta Blvd. already has concrete bridges to show where the run originally ran. The small wetlands would provide habitat for birds and butterflies, and would provide storm relief and some bioremediation as well. After a heavy rain, most of the water would be absorbed into the ground, while the existing pipes carry away the rest.

Robert E. Buxbaum, March 21, 2016

Follow the feces; how to stop the poisoning

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In Oakland county, we regularly poison our basements and our lake St Clair beaches with feces — and potentially our water supply too. We have a combined storm and sanitary sewer system that mixes feces-laden sanitary sewage with rainwater, and our pipes are too old and small to handle the amount of storm water from our larger rains. A group called “Save Lake St. Clair” is up in arms but the current commissioner claims the fault is not his. It’s global warming, he says, and the rains are bigger now. Maybe, or maybe the fault is wealth: more and more of the county is covered by asphalt, so less rain water can soak in the ground. Whatever the cause, the Commissioner should deal with it (I’m running for water commissioner, BTW). As the chart of toxic outfalls shows, we’ve had regular toxic sewage discharges into the Red Run basically every other week, with no exceptional rainfalls: only 0.9″ to 1.42″.

Toxic outfalls into lake St Clair, Feb 20 to Mar 20, 2016. There were also two outfalls into the Rouge in this period. These are too many to claim they are once in hundred-year events.

Because we have a combined system, the liquid level rises in our sewers whenever it rains. When the level is above the level of a basement floor drain, mixed sewage comes up into the basement. A mix of storm water comes up mixed with poop and anything else you and your neighbors flush down. Mixed sewage can come up even if the sewers were separate, but far less often. Currently most of the dry outfall from our old, combined sewers is sent to Detroit’s Waste Water Treatment plant near Zug Island. When there is a heavy rain, the pipe to Zug is overwhelmed. We avoid flooding your basement every other week by diverting as much as we can of the mixed storm water and septic sewage to lake St. Clair. This is poop, barely treated, and the fishermen and environmentalists hate it.

The beaches along Lake St Clair are closed every other week: whenever the pipes to Detroit start getting overwhelmed, whenever there is about 1″ or rain. Worse yet, the sewage is enters the lake just upstream of the water intake on Belle Isle, see map below. Overflow sewage follows the red lines entering the Clinton River through the GW Kuhn — Red Run Drain or through the North Branch off the River. From there it flows out into Lake St. Clair near Selfridge ANG, generally hugging the Michigan shore of the lake, following the light blue line to poison the metro beaches. it enters the water intake for the majority of Oakland County at the Belle Island water intakes, lower left.

The storm water plus septic sewage mix is not dumped raw into lake St. Clair, but it’s nearly raw. The only treatment is to be spritzed with bleach in the Red Run Drain. The result is mats of black gunk with floating turds, toilet paper and tampons. This water is filtered before we drink it, and it’s sprayed with more chlorine, but that’s not OK. We can do much better than this. We don’t have to regularly dump poop into the river just upstream of our water intake. I favor a two-prong solution.

The first, quick solution is to have better pumps to send the sewage to Detroit. This is surprisingly expensive since we still have to treat the rain water. Also it doesn’t take care of the biggest rains; there is a limit to what our pipes will handle, but it stops some basement flooding, and it avoids some poisoning of our beaches and drinking water.

This is our combined sewer system showing a tunnel cistern (yuk) and the outflow into the Red Run. We can do better

A combined sewer system showing a tunnel cistern. Outflow goes into the Red Run. We can do better.

A second, longer term solution is to disentangle the septic from the storm sewers. My approach would be to do this in small steps, beginning by diverting some storm runoff into small wetlands or French drain retention. Separating the sewers this way is cheaper and more environmentally sound than trying to treat the mixed flow in Detroit, and the wetlands and drains would provide pleasant park spaces, but the project will take decades to complete. If done right, this would save quite a lot over sending so much liquid to Detroit, and it’s the real solution to worries about your floor drains back-flowing toxic sludge into your basement.

The incumbent, I fear, has little clue about drainage or bio-treatment. His solution is to build a $40MM tunnel cistern along Middlebelt road. This cistern only holds 3 MM gallons, less than 1/100 of the volume needed for even a moderate rain. Besides, at $13/gallon of storage, it is very costly solution compared to my preference — a French drain (costs about 25¢/gallon of storage). The incumbents cistern has closed off traffic for months between 12 and 13 mile, and is expected to continue for a year, until January, 2017. It doesn’t provide any bio-cleaning, unlike a French drain, and the cistern leaks. Currently groundwater is leaking in. This has caused the lowering of the water table and the closure of private wells. If the leak isn’t fixed , the cistern will leak septic sewage into the groundwater, potentially infecting people for miles around with typhus, cholera, and all sorts of 3rd world plagues.

There is also an explosion hazard to the incumbent’s approach. A tunnel cistern like this blew up near my undergraduate college sending manhole covers flying. This version has much bigger manhole covers: 15′ cement, not 2′ steel. If someone pours gasoline down the drain during a rainstorm and if a match went in later, the result could be deadly. The people building these projects are the same ones who fund the incumbent’s campaign, and I suspect they influenced him for this mis-chosen approach. They are the folks I fear he goes to for engineering advice. If you’d like to see a change for the better. Elect me, Elect an engineer.

Dr. Robert E. Buxbaum, March 26, 2016. Go here to volunteer or contribute.

How to help Flint and avoid lead here.

REB Research Blog

Random thoughts about hydrogen, engineering, business and life by Dr. Robert E. Buxbaum

Category Archives: water

The straight flush

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Most flushable wipes aren’t flushable.

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just water over the dam

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The chemistry of sewage treatment

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Weir dams to slow the flow and save our lakes

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A run runs through it

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Follow the feces; how to stop the poisoning

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How to help Flint and avoid lead here.

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