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

Wooden Water Main circa 1909 source

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:

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:

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.

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:

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:

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:

Constructed Wetland Diagram source:

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.







1 TO 2

























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:

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:

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

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

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

Septic Tank Management

Homeowners are responsible for maintaining their septic systems.  It not only protects the investment in your home, but also protects your water supply and those of your neighbors.  You don’t want to be the cause of major ground water or surface water contamination because of a malfunctioning septic tank.  The liabilities are potentially huge and your homeowners insurance may not cover you if you didn’t do the required maintenance.   It will also make selling your home difficult,  I personally have walked away from houses I wanted to buy because the septic system was not in proper working order.

Septic tank management can be very simple. If the tank has been properly constructed and installed very few interventions will be necessary and the interventions will primarily be inspections.  The major components of a septic system are a collection pipe from the house, the holding tank, and the drainage system (usually a field).  The collection pipe is the final pipe leaving the home that contains all the household waste water.  This part of the system is identical for people connected to a municipal sewer except for where the pipe goes. Continue reading

Self-Reliant Liquid Waste Management

I have already written about how to develop a solid waste (garbage) management plan. If you are interested in living off grid, in a long term self sustainable way, you also need a solution to your liquid waste (sewage and others). There are two generic steps to accomplish this. The first is to separate the solids from the water and the second is a biological reduction of the organic material in the water and biosolids. If you are releasing into surface water there is frequently a disinfection stage as well and a dechlorinating stage after that.

There are two key groups of liquid waste. Biological waste, and industrial/chemical waste. Continue reading