Septic Tank and Inspecting

SEPTIC TANKS AND SYSTEMS

A sewage drain field and a septic tank make up a small scale sewage treatment system. A septic tank is basically a rectangular shaped underground receptacle for wastewater. It is watertight, made of concrete, and consists of tanks that are divided into chambers. The first chamber has twice the volume as the second and the majority of the organic solid matter, referred to as sludge, gets settled here. The second chamber further purifies the wastewater. The septic tank collects wastewater from toilets, showers, sinks, etc. Due to the absence of a current the sludge quickly settles down to the tank floor.

Anaerobic bacterial digestive activity on the sludge leads to the generation of methane and carbon dioxide; the sludge is stabilized and does not rot anymore. Particles of stabilized sludge stay settled, some may float to the top as scum. A septic tank should be constructed such that there is maximum contact time with the microorganisms so as to enable swifter digestion of the sludge. This is achieved by placing the inlet, overflow, and outlet diagonal to each other and by making the streams flow in vertically placed pipes. The semi-purified water moves to the second chamber via the overflows that are constructed such that the upward motion of water prevents larger particles from flowing into the second chamber. The feeding, digestion, and settlement of organic matter continues in the second chamber. The retention time in the second chamber is half that of the first chamber because of its size and the fact that the amount of organic matter to treat is less. The outlet is constructed in the diagonal corner to the overflow.

The treated wastewater is directed to a drain field, also known as a seepage field, where any impurities that still exist get decomposed naturally, the water is taken up by the plant root system or it may even become a part of the groundwater. The large sized drainage field is required if the soil is not very porous.

A septic system can be made to work entirely by using gravitational forces; at some places, however, a pump may be required to overcome topographical limitations. The rate of sludge generation in septic tanks is around 0.05 cubic yards every year for an individual.

Septic tanks need to be emptied every few years so that there is enough reaction space for the microorganisms to attack the wastewater and for the sludge to settle. The septic tank may be emptied every 5-7 years depending upon the amount of wastewater it processes. The tank is emptied using an exhauster truck manned by trained personnel. The sludge that is sucked into the exhauster truck is released into public waste water treatment plants, sanitary landfills, or sludge drying beds. Properly digested sludge can be used as a natural fertilizer; this is possible only if no fresh wastewater is added to the tank for at least one week. The design of the septic tank should be such that the wastewater always flows in its designated path and no short circuits in the water flow occur. T-pipe-connectors with inflow and outflow openings under the water level should be used for inlet, overflow, and outlet pipes. This prevents the floating scum from clogging the pipes. A grease trap should be provided for the wastewater inflow pipe.

When you buy a car, you are given an owner's manual with instructions on how to care for your car. Septic tanks can cost as much or more than a car, unfortunately nobody gives you a manual when they are installed. Some people don't even know they have a septic tank! As a result, many septic systems fail unnecessarily. The Price for Failure is Steep The price for failure is steep in two way. More than 1200 people in the US die each year from contaminated water, and failing septic systems are a leading source of waterborne disease outbreaks in the country today. In a 2000 EPA report, 31 states listed septic systems as their second greatest potential source of groundwater contamination. Septic system replacement is also very expensive, with costs often running from $5,000 to $20,000 or more. Fortunately, there are some highly effective, ineffective steps you can take to eliminate this problem. Before discussing solutions, let's look at why septic systems fail. Septic tank maintenance is actually pretty easy to understand. When a system fails, the tank itself doesn't fail - the drainfield soil fails. In most cases the soil fails when it gets plugged up with solids and won't allow liquid to pass through it. For example, it can get plugged with solids from the tank if the tank hasn't been pumped, or with lint from a washing machine. Now for your solutions:

1. Use a washing machine filter. Did you know that washing machines are a leading cause of septic system failure? The primary culprit is lint generated by washing machines, which clogs the soil in drain fields. Did you know that a typical family washing machine produces enough lint each year to carpet and entire living room floor! Lint screens and nylon traps found in hardware stores trap 5% or less of these particles. Because they are so light and small, the lint particles do not settle out in the septic tank. Instead, they stay in suspension and are flushed out to the drain field, where they plug up the pores of the soil bed. To compound the problem, much of our clothing is now manufactured with synthetic materials such as polyester and nylon. These substances are not biodegradable, and will not break down in a septic system. Instead, they accumulate and plug the soil. Once these materials enter the soil, there is no way to remove them. The good news is that lint can be prevented from entering the septic system through the use of a reusable, inline filter which attaches to your washing machine discharge hose. The filter, called the Filtrol 160, retails for $139.95.

2. Avoid Excessive Water Use You can also damage your septic system by doing a large number of laundry loads in a short period of time. In standard septic systems, solid materials settle in the tank, while effluent flows out into the ground. If you put more water into the system than it is built to handle, the high volume of water will flood your system, and can also stir up and flush solids out of the tank into the drain field (in fact, septic pumpers use water from their hoses to help break up solids in your tank before pumping them out). A typical washing machine can use up to 60 gallons of water per wash load. On a heavy day you can easily put 400, 500 or 600 gallons of water through the system in a few hours. The solution is to spread out your water use. Do one or two loads of laundry per day, rather than 10-12 loads on Saturday morning. Water softeners can also damage your system by putting too much water through the septic system. These devices can put several hundred gallons of water down the drain every week, water that is not contaminated and does not need to go through the treatment process. There are a couple solutions to this problem. You can upgrade your softener with a newer efficient model that uses less water and regenerates on demand, instead of a timer system that regenerates whether you use water or not. You can also install a mini septic system for your water softener.

3. Prevent Solids from Leaving the Tank First of all, you should get your tank pumped on a regular basis to prevent excessive accumulation of solids in the tank. Under normal conditions, you should have the tank inspected and pumped every 1-3 years. Very important: tanks should be pumped and inspected through the manhole cover, not the inspection pipe. Your septic contractor should also install an effluent filter in the exit baffle of the tank. Effluent filters stop the larger solids from getting out to the drainfield. They are cleaned out every few years when you have your tank pumped. They are usually only about $80. Effluent filters are cheap insurance and along with a washing machine filter, one of the best things you can do to protect your system.

4. Use of Household Cleaning Products Excessive use of these products can contribute to septic system failure. If you do over 5 loads a week containing bleach, problems could arise. Avoid powdered detergents as they contain plastic fillers that can plug up your lines and drain field. Also, be careful with harsh automatic toilet bowl cleaners, which have put quite a few systems out of commission.

5. Should I Use a Separate System for My Washing Machine? Some people say you should use a separate system for your washing machine, called a laundry interceptor. However, this is not necessary and in fact undesirable. Washing machines should discharge into the regular system because it actually works better than discharging into its own system. In order to work, septic systems require bacteria colonies which break down biodegradable matter. These bacteria require "food" which is found in our wastewater, but not in detergent. Without "food" these bacteria colonies die out and the system fails. Many people who have installed these systems have found this out the hard way. A research project conducted in several east coast states utilized some rather high tech systems for washing machine discharge and many began failing in as little as eight months.

Septic Tank Maintenance Tips:

Do:

Divert surface runoff water from roofs, patios, driveways and other areas away from your drainfield.
Have your septic tank pumped regularly. It should also be inspected for leaks, cracks and to make sure the exit baffle is in place.
Install lint and effluent filters.
Spread out your laundry loads.
Compost your garbage or put it in the trash

Don't:

Use a garbage disposal. These appliances normally double the amount of solids added to the tank!
Flush sanitary napkins, disposable diapers or other non-biodegradable products into your system.
Dump solvents, oils, paint thinners, disinfectants, pesticides or poisons down the drain as they can disrupt the treatment process and contaminate the groundwater.
Dig in your drainfield or build anything over it.
Drive over your drainfield or compact the soil in any way.
Plant trees or shrubbery close to the septic system, because the roots can get in the lines and plug them. Grass is the only thing that should be planted on or near a drainfield.

If Your System Fails In quite a few cases, a tune-up can fix your system and you can avoid the high costs of replacing the system. This tuneup includes properly pumping the tank, cleaning (jetting) the drainfield lines, and installing washing machine and effluent filters. If these measures are not sufficient, some failed systems can be rejuvenated by fracturing the soil. This process utilizes a hollow tube inserted into the soil, then a 300 pound blast or air is injected into the soil creating thousands of tiny fissures. These fissures allow the drainfield to drain, creating an oxygen atmosphere and the aerobic bacterial colonies to repopulate. Aerobic bacteria, which require oxygen, typically live in the top 26 inches of the drainfield and process waste much more quickly than anaerobic bacteria. This process can be performed in a matter of hours with no digging or damage to the yard.

If you have a clay soil which has become plugged due to sodium from wastewater binding with the clay, Septic Seep can help. These product releases sodium bonded clays and reopens soil, restoring passages air and water. It also has the benefit of dispersing greases and scums that clog the soil.

Buying a Home with a Septic Tank

As a home inspector I always recommend that the Buyer have the Septic Tank pumped out by a Licensed Septic Tank Installer. Any experienced Septic Tank Installer can tell you and provide a written report on the condition and functioning of your septic tank by inspecting the sludge when removing. This is by the far the best method of having your septic system inspected. A local septic tank installer has probably pumped out the tank a number of times and may have originally installed it.

Barrie Home Inspector	Office Phone: (705) 795-8255
Stollar Blvd, Barrie	Inspection Scheduling: (888) 818-8608
Alliston, Barrie, Orillia, Simcoe County	Email: Click here to contact us
WETT Inspections