Effects of Bleach on a Septic System

Because the key to a functioning septic system is the bacteria that lives in your septic tank, an overload of harsh chemicals, such as bleach, could potentially kill off the bacteria in your tank and cause problems in your overall system. The bacteria in the tank provides an anaerobic (meaning that oxygen is not required) breakdown of solids in the tank.     

According to a recent research study (Gross), bacteria in a septic tank can be killed if there is an overabundance of toxic substances. Research showed that 1.85 gallons of liquid bleach, 5 gallons of a liquid cleaner or 11.3g of a drain cleaner in a standard 1,000-gallon septic tank can cause a bacteria “die-off.” The study noted other substances that were harmful to the tank bacteria including anti-bacterial soaps and cleaners.

A short-term use of household cleaners should not cause a permanent die-off of septic tank bacteria, but long-term use resulting in a bacteria die-off could result in greases, oils and solids being pushed out of the tank into the drain field. If these elements get into the drain field, it can result in blockages and ultimately a failed drain field system. Symptoms of a failed drain field include slow drainage and flushing of drains and toilets in the house, as well as standing water on the grass or soil over the drain field. A completely blocked drain field will cause a backup into the house.

Discontinuing the use of harsh cleaners and chemicals is the first step. Over time, bacteria will naturally begin to reproduce in the tank, and a live colony should become established. Although many over-the-counter additives are sold, these substances can actually lead to septic tank problems as the solids and “scum layer” in the tank are often broken down and then flushed into the drainage system, causing blockages.

GROWING VEGETABLES OVER A LEACHING BED IS NOT RECOMMENDED

Growing vegetables over a drainfield is not recommended.  There are several reasons why:

• septic systems receive household wastes from toilets, sinks, showers, dishwashers, washing machines and other indoor water uses
• the leaching bed part of the septic system most commonly consits of a series of parallel perforated pipes in the grund about 12 to 18 inces deep.  The pipes are set in gravel trences that allow treated effluent from the septic tank to seep into the ground.
• the leaching bed is the most expensive and the most potentially problematic part of your entire septic system
• vegetables need watering and excess water in the soil would reduce the leaching bed's ability to treat the wastewater
• the water does not go straight down, it diffuses out first
• during heavy rain, run-off, or snow melt water can actually go up, and rise in the soil
• while nutrietns may be beneficial for the plants to a degree, excess Nitrogen also poses problems for plants and all the bacteria in the soil may not be quite so beneficial
• the deep roots of some vegetable may damage the drainfield pipes
• bed preparation, such as roto-tilling or deep digging can also damage the drainfield pipes
• the soil over the leaching bed tends to settle over time and that allows roots access to it causign plugging of the field as weall as contamination of any foods grown there
• the leaching be perforated pipes are only buried 12-18 inches under the ground so digging or roto-tilling in your garden could damage the pipes   
  

Leaching Bed Maitenance

Keep heavy things away from the septic bed

Driving cars or machinery over your septic system will crush it. The soil surrounding the pipes may become compacted, making it less able to absorb the wastewater coming out of the pipes.

Snowmobiles compress the snow cover over the septic field, reducing its natural insulating effect and increasing the risk of freezing pipes.

Be a mindful gardener

Planting trees and shrubs (especially willows and poplars) near the field is risky because their roots travel significant distances to seek water and can plug or damage the pipes.

And watering of the grass over the field, whether by in-ground systems or by hand should be eliminated or minimized. Watering interferes with the soil’s ability to absorb liquids and break down wastes.

Source:  Ontario Ministry of Environment

Septic System Setbacks

BIOMAT EXPLAINED

Biomat on bottom & sides of leaching bed trench

Biomat found in soil sample from a soil auger

Biomat is a naturally occurring tar-like substance that forms on the bottoms and sides of the leaching bed trenches.  This layer is critical in the processing of fine biological solids and pathogens which are in the effluent, and without it the septic system would not be adequately treating the septic system effluent. Inadequately-treated effluent released into the ground risks contamination of nearby ponds, wells, streams, etc. A similar layer also forms around drywells used to accept greywater from buildings.

It is made up of living anerobic (without oxygen) organisms, which feed on organic matter in septic system wastewater.  As the biomat ages it grows thicker slowing down the flow of wastewater to the surround soil.  As the wastewater passes through the biomat, pathogenic organisms and viruses are removed.  On the outside of the trench, beyond the biomat where the soil is not saturated, are living colonies of aerobic (with oxygen) bacteria.  These aerobic bacteria colonies feed on the biomat and keep it from becoming so thick that wastewater will no longer pass through.

When soil floods these aerobic colonies will die off and no  longer keep the biomat in check.  The biomat will grow too thick and drainage will stop.  As these colonies die off they leave behind sulfides, which over time will clog soil passages stopping the flow of water, when the biomat grows too thick a waterproof barrier develops and absorption stops.



 

Clogged Drain Pipes - First in a series of Four reasons why a septic system fails


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Clogged drain/leaching septic system pipe
  

One of the reasons a septic system fails is due to "biomat" build-up inside the tile bed/leaching field area.  Biomat is a build-up of a black sludge material that clogs everything it comes into contact with.  Evidence of a biomat clogged leaching bed are:

• the ground around the septic tank or over the leaching bed may be soggy or spongy to walk on
• toilets, showers and sinks may be slow to drain or even back up
• sewage odours may become noticeable especially after a rainfall or when you have company
• gray or black liquids may be surfacing in your yard or backing up through fixtures into the house/cottage
• E. coli or faecal coliform indicator bacteria may be found in nearby well water or in a surface ditch close to the leaching bed
• the water level in the septic tank is higher than the outlet pipe which indicates that the water is ponding in the distribution lines (inspection should only be conducted by a qualified person)
• sewage effluent  is ponding in the distribution lines (inspection should only be conducted by a qualified person)

Refer to Biomat Blog (July 31, 2012) for additional information

  

  

  

"YOU ASKED" What questions should I ask during a real estate transaction of a property with a septic system?

I am buying, what should I ask the vendor?
If you are buying a property with an on-site system, you should ask the following questions:

• How old is the system?
• Does the system have a permit? Ask for a copy.
• Is the septic system working properly (no sewage back-up, foul odours noticed)?
• Where is the septic tank and leaching bed?
• How often has the tank been pumped? By whom?
• Have there been any repairs? If so, what did they consist of? Who performed them? What was the cost?

I am selling a property with an on-site system, what should I tell the buyer??
If you are selling your property, you should give the buyer the following tips:

• Pump the tank every 3 - 5 years;
• Do not pour hazardous chemicals down the drain, harmful chemicals will pass through the system and may end up in the groundwater;
• Do not use septic tank additives (not proven effective, may be harmful);
• practice water conservation (less water used, the less your system has to treat);
• Don't use a garborator;
• Must have a permit to repair a system;
• Must contact local inspector if putting an addition onto the house, or adding a Jacuzzi or pool etc.;
• Divert roof drains away from the tank and drainfield (can overload >saturate= the soil in the area).

What should I look for when assessing a property?
Look for the following items when assessing a property with an on-site system:

• Presence and location of the septic tank and the leaching bed;
• Accessibility of tank for maintenance;
• Roof drains directed onto the leaching bed;
• Leaching bed has been shaped to shed water;
• Trees and bushes are planted away from the leaching bed

Source:  Ontario Rural Wastewater Centre