Ageing Infrastructure

What do you think is the most likely reason for a water grid shutdown?  It isn’t terrorism and it isn’t pollution. The answer is, the age of the infrastructure used to deliver the water or collect the sewage. Think about the city you live in. Chances are it has existed for hundreds of years, if not longer. Most cities water systems grow in phases. They keep adding to the network every year as the population grows. The end result is most cities have infrastructure that range from less than a year to hundreds of years and with many different materials. I have seen water mains made of wood in service as late as 2011. Like any piece of equipment it all has a useful lifespan, beyond that lifespan failures become increasingly more likely to be catastrophic. The result is a large volume and dollar amount of material and equipment that needs repairs or to be replaced.

Wooden Water Main circa 1909 source www.nytimes.com

Wooden Water Main circa 1909 source http://www.nytimes.com

Normally the stress on water systems comes from population growth.  A water main that was ok in the 1980’s may not be large enough for today’s population.  As cities infill and build higher density buildings they frequently overburden the water systems.  Either causing contamination or total failure of the system.

Older equipment is also more susceptible to natural disasters, terrorism and human accidents. These three things can break a new system too, however they don`t have to try as hard with the older systems.

Climate change is having an affect too.  As severe weather events are on the rise, storm sewers might be found lacking, as was the case in Calgary, Alberta and Toronto, Ontario recently.  The system was grossly undersized for the amount of rain that fell.  They said things like “it was a month’s worth of rain in one day” on the news.  When the fact is, it once was a months worth of rain, and is now something more frequent, lets say a weeks worth of rain.    I’m not suggesting we build our systems to meet a 1000 year storm, but I am suggesting that our current idea of a 100 year storm may be an underestimation and that the error is getting worse.  To bring it back to infrastructure, if we are built to the current 100 year storm levels, what happens if the 100 year storms are getting worse?  We will find out in the not too distant future.

Calgary, Flood, Floods, Water

Flooding In Calgary AB 2013 source: http://www.newinfills.ca

What are the options for people to take? The first and most important thing to do is to plan ahead and replace older parts of the system before they fail.  A $50,000 job to replace an old section of pipe at a time you choose is a lot cheaper than waiting for it to fail at the time you are least prepared.  If you are connected to a public utility, ask them about their equipment replacement plan.  If they are not looking 25 years into the future or longer then ask them why not? If you have private systems, you need to ask the same questions.  Can you afford to replace the septic system when it fails? Or can you afford to dig/drill a new well when the casing cracks?

As you can probably surmise the addition of more people + more rain + more water and more sewage means system failures will become more frequent and probably for longer periods of time.  What does this mean to the average person?  Plan for system failure.  Have a backup system ready to go when it does.  Know the age of your equipment and it`s expected lifetime. That way you wont be caught off guard.

Septic Tank Problems

Septic systems range from the very simple to the extremely complex. Even on the simplest septic systems there are still many things that can go wrong. If you believe that septic systems are something you bury and forget about, then I guarantee that you will come across many of these problems. There are simple things anyone can do to keep their septic system running properly for decades.

First a general description of a septic system. The system starts where the common drain leaves the house. This drain can go to a municipal sewer or to an individual septic system. The water flows by gravity into the septic system. The inlet to the septic tank is protected by a T shaped baffle. It is open on the top and bottom. It is designed to contain floating debris in a small area and to direct solids to settle down towards the bottom. The water is contained here where solids settle out to form a sludge layer and floating objects form a scum layer. In between there is a clear zone where the water has very few solids. The water in the tank is treated by anaerobic bacteria. The bacteria break down organic compounds in the water until there is almost nothing left.
The water leaves the tank through another T shaped baffle on the other side of the tank. This one goes down to the clear zone and allows clear zone water to exit the tank without coming into contact with the scum layer. Some tanks have a septic pump, the pump is installed on the opposite side of the inlet and at the expected height of the clear zone. Larger tanks might have a dividing wall to keep sludge and scum on one side and clear water on the other side.

Septic Tank, Septage, scum, sludge, clear, zone

Basic Septic Tank Design (source: biozoneseptoc.com)

The sludge layer if not removed every three to five years can cause a major failure of the entire system. Not everything can be broken down completely.  There are always things that either never breakdown or breakdown too slowly and they accumulate.  The sludge layer will eventually reduce the capacity of the tank and the solids will block the inlet or the outlet of the tank.  The sludge layer will be a rapid problem if the people using the system treat the toilet as a garbage can.

The scum layer is all the floating solids the get flushed into the system. Grease and oils cause a large part of the scum problem. But they are far from the only culprits. Cooking oils and grease coat the walls of the pipes and tanks and slowly reduce the size of the of the inlet and outlet eventually blocking them, and you can see how that is a problem.

The drain field is where the treated effluent gets released back to the environment. It may be called something else like a tile bed or weeping tile. They are usually subterranean but can sometimes be on the surface. Regardless there are still buried pipes and they are easy to collapse if you drive a vehicle over them. Lawn tractors are OK but even compact cars are too heavy for the shallow plastic piping. If the piping becomes cracked or even a section collapses then pipe will become blocked with dirt and your waste water will have nowhere to go except back into the house.

Hydraulic overloading is the technical name for putting too much sewage into your septic tank.  This can happen if you have a party and there are more people using the system or if the sludge layer reduces the capacity of the tank.  The end result of overloading is that poorly or untreated sewage leaves the system negatively impacting the surrounding area.

Leaks are bound to occur with age.  You can also create leaks by driving over the tank and excavating too close to the tank.  Leaks are a huge problem once they occur.  The groundwater and soil contamination is extremely expensive to clean up.  You may also be liable for damage to the neighbor’s water supply depending on the riparian laws where you live.  A leaking tank needs to be replaced immediately.

Proper maintenance will prevent most problems.  The worst thing anyone can do is to bury the septic system and forget about it.

Why is my water that color?

As someone who works in water treatment I fequently receive questions about red, black, pink or cloudy appearances in drinking water. Contrary to what might be expected none of these colors are inherently dangerous to human health. They do however make the water look unappetizing. They are called asethetic water quality indicators. Well the colors themselves isn’t the indicator, what causes the water is. I will outline the causes below.

Red water is usually caused by the oxydation of iron and iron bacteria. To be a little more accurate the color is a reddish brown, if you see a red that belongs in a paint can then I highly recommend NOT drinking it. Iron oxydation (rust) is not dangerous at all. Many water sources contain iron naturally. Iron is prevalent in groundwater. The red color comes from iron particles rusting when they come into contact with oxygen in the water. The rusting is accelerated when the iron is introduced to chlorine. As you know chlorine is very commonly used as a disinfectant. When there is a lot of iron and a lot of chlorine then there can be a visible particles of rusted iron in the water. This looks really bad when you turn on the faucet but iron is something they add to mineralized bottled water and iron is a necessary element in proper nutrition.
Iron bacteria can enter the water at the source or if the water is stored in a metal container or watermain. Wells can become contaminated with iron bacteria. When they do, read this to know what to do about it.

Black colored water is not to be confused with black water which is a term used for sewage. Sewage is often a yellowish brown, unless it has gone septic and then it is very black and very smelly. An odorless black tint to water is usually due to manganese. Manganese behaves a lot like iron does except it oxidizes a lot slower. Water stored for a couple days or more will turn black if there are high levels of manganese in the water. Manganese is more often found in groundwater than in surface water. Sometimes it wont be noticeable in the water. It will however be noticable as a black stain on appliances and reservoir walls.

Pink water comes from potassium permanganate (KMnO4). Permanganate is a treatment chemical used to help oxidize iron and manganese. When too much is added the water turns pink. When a lot is added then the water turns purple. The pink isn’t dangerous to human health. It is hower alarming to see pink coming out of a faucet. To read how to use potassium permanganate as a disinfectant read this.

To remove iron, manganese and permanganate is accompolished with greensand filtration. Don’t let the name fool you, greensand is black in color. Greensand is chemically activated to remove oxidized minerals from water.

A yellowish tint (sometimes brown) to the water IS potentially dangerous. Yellow tea colored water is indicative of organic material in the water. Organic material is mostly non living particles but it also includes bacteria, viruses, and other pathogens. Sewage is also this color. So beware of yellowish water.

Not many different things can cause a truely cloudy appearance to water. Turbidity is sometime said to be “cloudy” but it is caused by suspended particles blocking light from passing through. Usually turbidity is also colored at the same time. Unless the particles are white in color, then turbidity isn’t cloudy, it is dirty.
Cloudy water is caused from dissolved gasses (usually oxygen) in the water getting released. This happens when the temperature in the water is significantly different than the temperature of surrounding environment. Since large bodies of water are slower to heat up and slower to cool down, this difference happens every spring and fall. It is called reservoir turnover. The way to test if it is just dissolved gasses in the water is to let a glass sit for five minutes. All bubbles of gasses will disappear and the water will look and taste normal. If the water is still cloudy after five minutes, then the problem is caused by turbidity and it must be removed by filtration.

Not everything that can happen to drinking water is dangerous. Reddish tints from iron and blackish tints from manganese are natural and harmless. This article should help you determine when visual changes to the water are cause for alarm and when they can be ignored safely.

Down the Drain: Persistent Chemical Contamination

What do you do with your unused and expired medications? How do you get rid of used motor oil and solvents? Your painting is done but you have some paint left over, what do you do with it?
Many people will say “I pour it down the sink or flush it down the toilet”. Even more people will lie when they say they don’t put it down the drain. Your drains are not garbage disposals for all our waste. Doctors usually recommend that expired medications get flushed down the toilet. This line of reasoning is to prevent children and pets from consuming the drugs. Maybe a doctor can expand on their reasoning more, the purpose of this article is to make a case for why using the toilet to dispose of medication is a bad idea.

Why is dumping things down the drain such a bad idea? The answer is both simple and complicated at the same time. The simple answer is that everything that goes down the drain in whole or in part survives long enough to make it back into drinking water supplies. The long answer is that contaminates survive the sewer and waste water treatment and are released back into the environment with the treated water. Then the lakes and rivers are used for drinking water. The contaminants survive the drinking water treatment and enter our drinking water. Most of these contaminants survive because the largest part of waste water treatment is biological. Therefore, anything non organic will either pass through the treatment or disrupt the treatment process or become part of the biological organisms that are there to break down waste.

In either scenario, and really all scenarios happen all the time, contamination enters the environment. In 2011, a shipment of municipal biosolids from Ottawa, Ontario, Canada was refused at the American border. The biosolids are supposed to cross the border for disposal. This shipment was refused due to radioactivity. The radioactivity came from cancer patients as the chemicals from chemotherapy pass through the body and the wastewater plant all while remaining radioactive. Radioactivity is easy to detect and in this example the chemicals came from people’s bodily waste which is supposed to go down the drain. I only mention this example because it so clearly outlines how persistent many chemicals can be.

Some chemicals mimic our hormones and disrupt our natural body systems. They have been found to cause feminization of fish and are believed to cause early onset of puberty in humans. These chemicals can come from people’s medication and from all our waste. BPA is the most famous hormone mimic. It come from the breakdown of plastics and mimics estrogen in humans. Other pharmaceuticals tend to do what they are designed to do, just now they are affecting the wrong people. Most other chemicals just cause cancer.

This contamination isn’t limited to water. Earlier I mentioned that the chemicals can enter organisms. This is especially true of plants. Plants will absorb these chemicals and then they enter the food chain. I won’t describe the food chain here, all you need to know is that the concentration increased the higher up the chain. This is called biomagnification. The apex predators get poisoned first. The main problem with biomagnification is, we are the species that eat the most other animals.

There was a study in Scanadnavia that found flame retardants in cancer patients. They traced the chemical back to the bread they had all eaten. Then back to the wheat in the field where biosolids were spread. The flame retardants were found in the municipal wastewater facility and the municipal sewers. It was traced back to one manufacturer who was putting flame retardants down the drain as part of their process. I can tell you this happens everywhere. Even if you live on a remote septic system, there is always someone upstream. Hardly seems worth it for dumping chemicals down the drain.

You might be wondering why this matters to you. Simply, it matters because we all have a part in what we put down the drain. This is true whether you live in a large metropolitan area or a remote cabin on a well and septic system. What we release into the environment comes back at us in many different directions. Detecting these chemicals is difficult because there are so many different chemicals out there that nobody can check for them all or even most of them. A lot of these chemicals pass through store bought filters. Many of these molecules are smaller than the water molecule. That means every filter is ineffective against them. To put is simply, this problem affects everyone.

Septic Tank Alternatives: Lagoons and Constructed Wetlands

Septic tanks and a subterranean discharge is the single largest way people rural communities treat waste water. That is, in places where the soil, topography and hydrology allow for underground discharge.
The other limitation of septic systems is the capacity, if you expect large volumes of water then you need a large tank/multiple tanks and that can be very expensive.

Constructed Wetland at the Edmonton International Airport source: watercanada.net

I have already written a fair amount about septic systems, and in this article I am going to explore some of the other options for onsite watsewater treatment. Then next two most common options are Lagoons and constructed wetlands. A sewage lagoon is a water-tight earthen berm including the bottom. The construction is not complex, but it can become land intensive depending on the size. Constructed wetlands are identical to lagoons but they are allowed to grow over with vegetation forming a complete wetland ecosystem.

Sewage Lagoon Site Plan source: elkhorn.unl.edu

Lagoons are sometimes referred to as stabilization ponds. In a basic level, they reduce organic contamination in domestic sewage down to levels suitable for release back into the environment with minimal impact. If they are operated correctly, they can have a positive effect on the receiving water way. The lagoons I operated have lower phosphate, ammonia and nitrogen levels than the river they discharge into.

Constructed Wetland Diagram source: www.civil.columbia.edu

Constructed Wetland Diagram source: http://www.civil.columbia.edu

Lagoons are best constructed with a bulldozer or front end loader because it will be easier to create even depth impermeable layers of soil. The impermeable layers are constructed by compacting clay based soils into a water tight layer. If the available soil is impractical for compaction, a layer of sand topped with a plastic/rubber liner at least 30mm thick. There are professional installers and commercial DIY options available.  Below is a table from University of Missouri outlining the size and space a lagoon requires.

NUMBER OF BEDROOMS

MINIMUM SEPTIC TANK LIQUID CAPACITY1(GALLONS)

LAGOON WATER SURFACE AREA2(SQUARE FEET)

SQUARE LAGOONS(FEET SQUARE)

ROUND LAGOONS (FEET DIAMETER)

ESTIMATED AREA NEEDED FOR ENTIRE LAGOON (SQUARE FEET)

1 TO 2

1,000

9003

30 FEET

34 FEET

5,800

3

1,000

1,320

37 FEET

41 FEET

7,050

4

1,250

1,760

42 FEET

47 FEET

7,750

5

1,500

2,200

47 FEET

53 FEET

9,200

1FOR HOMES WITH MORE THAN FIVE BEDROOMS, TANK VOLUME IN GALLONS = (1.5 X DAILY SEWAGE FLOW) + 500.
2ADD 440 SQUARE FEET OF WATER SURFACE AREA FOR EACH ADDITIONAL BEDROOM.
3MINIMUM LAGOON WATER SURFACE AREA IS 900 SQUARE FEET AT THE 3-FOOT OPERATING LEVEL.

You may be wondering how a lagoon/wetland system can handle larger volumes than a septic system. The answer is oxygen. Septic systems operate under anaerobic conditions meaning they are oxygen deprived. Lagoons and wetlands are facultative. Facultative environments are partially aerobic, and partially anaerobic. In a lagoon the surface is aerobic as oxygen from the atmosphere is added to the water and the deeper you go the more anaerobic conditions become. Aerobic conditions allow a much more efficient bacteria to break down the waste. These more efficient bacteria are surprisingly named aerobic bacteria.

Aerobic and Anaerobic Processes in a Sewage Lagoon source: elkhorn.unl.edu

If a lagoon or wetland is operating properly, there will be a musty smell.  This is the same smell produced by natural wetlands, if you have ever been to a swamp you know the smell I am referring to.  If the oxygen balance is disrupted, for any reason, either overloading or ice cover or chemical contamination the process will turn septic/anaerobic.  Then the lagoon will produce a wide bouquet of odors, most notably a rotten egg smell caused by the formation of hydrogen sulfide.  If you have ever opened a septic tank and caught a whiff, that is the smell I am referring to.  If you decide to treat your onsite waste this way, maintenance of the oxygen balance is critical to avoid the inferior treatment and smells of anaerobic conditions.  Simple things like keeping trees at least 50 feet away from the lagoon will add more oxygen to the water by allowing for more sunlinght (photosysthisis produces oxygen) and wind contact (physically transfers oxygen to the water).  In extreme cases pumping water so it circulates to the surface will also add a lot of oxygen, as will pumping air directly into the water via an air compressor and diffuser will almost guarantee you never see anaerobic conditions.

Constructed Wetlands in Series source: http://www.mda.state.mn.us

Sometimes waste systems are combined and there is a septic tank that feeds into a lagoon or wetland and then into a receiving water system.  This arrangement can improve all around wastewater treatment and extend the life of the entire system.  If your local regulations and soil conditions allow for these types of waste water treatment they are definitely worth considering.  Properly maintained and properly designed they can become an attractive and functional feature to any property.

Sewage Emergency: Thunder Bay Flooding

Recently the city of Thunder Bay Ontario experienced devastating flooding. There was enough water to flood out the waste water treatment plant. This effectively shut down the sewage collection and treatment system for the entire city. This turned the entire city to a zone without sanitation.  Over 1000 houses needed to be evacuated, and some people needed to evacuate immediately.

Contaminated Water Flooding Thunder Bay (from news.nationalpost.com)

The flood hit the city at night, and people living in basement apartments woke up to furniture floating in sewage.  One lucky family woke up to their baby’s crib (and baby) floating in sewage.  The rest discovered that their house smelled horrible when they woke up.

What overloaded the system was a prolonged rainstorm above the 100 year storm levels and the normal waste water levels. Combined sewers meant that all this water was supposed to be treated at the waste water treatment plant.  When the flooding reached the facility, the pumps shorted out, as in most large facilities most of the control electronics (there are a lot) are stored in the basement.  Electronics underwater rarely fair well, this shut down the entire facility.  Large volumes of contaminated water had nowhere else to go and it started covering most of the city. People had anywhere from 4 inches to 6 feet of sewage in their homes.

Sewage Flooded Basement (from cbc.ca)

The city instructed residents not to use water, because all the flushed toilet water was ending up in basements and free flowing in the street. People didn’t stop washing and flushing. Now, when there is sewage everywhere there is a huge need to wash and keep clean. But when all you have is water for hygiene, all that waste will end up in the street or in your basement.  So there are strong reasons to use water, and strong reasons not to flush anything down the drain.  This is a good reason to have water-less cleaners available for when the waste has nowhere to go. Alternatively it is also a good reason to have short term storage for household waste.  There is no point in flushing the toilet if it just ends up in your basement.  I would personally deal with twenty feces filled buckets then one flooded basement.

When there is sewage in your house the environment becomes so toxic that even sleeping overnight can cause respiratory illnesses. Continue reading

How Big Of A Septic Tank Do I Need?

Septic systems are the most common type of sewage treatment for people living off of municipal or communal sewage systems.  The treatment of sewage is necessary even for people going “off grid”.  Most, and probably all jurisdictions in North America have some requirements for sewage treatment.  Treating sewage is also significantly better for the environment as exposure to untreated waste water is a common way to spread disease in humans and other animals.  Septic systems break down the organic components in sewage and provide water that is safe to be released into a form of biological treatment.  This is usually soil, in the form of a drain field.  I frequently get asked how large a septic tank is needed for someone installing or upgrading their waste management system. How large a tank needs to be ultimately depends on how much water will be put through it.

Predicting how much water will enter your septic tank will can be simple, or it can be very difficult but it always starts with your water use. To estimate your water usage there are some things you will need to know.
How many people are in your household? How many people are usually in your house and on your system?  This includes visitors which only visit once a year. How much water are you currently using? If you have a water bill now you can see it easily.  The water you use day to day becomes the waste water you have to deal with later.  The age of people in your household will play a factor.  Even if you are good at conserving water, children will waste a lot more water and they require more water in the form of bathing and laundry.  Both of those traits will increase the demand on your septic system when many kids are around.  Larger septic tanks are required for people not used to conserving water, when choosing your tank size, try to remember, most people are horrible at conserving water.

Ok, here are some guidelines for determining the size of the tank required.  The smallest tank size allowed in some jurisdictions is one thousand gallons.  A one thousand gallon tank can handle around 600 gallons of sewage per day.  In terms of percentages, a septic tank should he 40% larger than the flow of sewage into it, or the sewage flow should not be greater than 60% of the tank capacity.

What if you do not know how much water people are using or how much waste water you are creating?   Continue reading