Background

The most common wastewater treatment system used in rural areas is the septic tank-soil absorption system. The septic tank removes solids from the wastewater, and the soil absorption field (drain field) filters, treats and disposes of the septic tank effluent.

You can find more information on our web, so please take a look.

Removing the solids from the wastewater protects the drain field from clogging and early failure. The septic tank also stores the settled solids and allows biological digestion of some of these solids.

How Does a Septic Tank Work?

1. The septic tank removes solids by holding wastewater in the tank, which allows the solids to settle and scum to rise to the top. Incoming water should be held in the tank for at least 24 hours in order to improve settling. Up to 50% of the solids will decompose into liquids and gases. The remaining solids accumulate in the tank.
2. Biological and chemical additives are not needed to aid or accelerate settling or decomposition. As a general rule, no solids other than human wastes and white toilet paper should be flushed.
3. As the septic system is used, sludge continues to accumulate in the bottom of the septic tank. Properly designed tanks have enough capacity for three to eight years use before needing service. The tank should be checked each year starting with the third year to determine how much sludge is there. It is important to understand that septic tanks always appear full because both the inlet and the outlet are at the top of the tank. The homeowner needs to determine how much of the tank's volume is being taken up by solids, scum and sludge. 
4. When sludge and scum take up more than 35% of the tank volume, these solids need to be removed by pumping.

Servicing a Septic Tank

When too much sludge and scum are allowed to accumulate, the incoming sewage will not have enough time in the septic tank for solids to settle. Solids may flow to the drainfield and clog the drainfield, causing the sewage to overflow to the ground surface, where it exposes humans and animals to the disease-causing organisms in sewage. To prevent this from happening, it is very important to check the tank and have it serviced when needed.

The drainfield may not fail immediately when a full tank is not pumped. However, the septic tank is no longer protecting the drainfield from solids. This creates inefficiencies in the drainfield and may allow contamination of the groundwater. Continued neglect will result in failure of the drainfield, and it may need to be replaced. The frequency of pumping depends on the size of the tank and what and how much goes down your drains. Use of a garbage disposal and excessive water use can increase pumping frequency.

In Oregon, a 1,000 gallon septic tank is used for homes with up to four bedrooms. If four people live in a four-bedroom house, a 1,000 gallon tank may need to be pumped approximately every three years. If the same system serves a family of two, the tank would be ready for pumping every six years. Systems installed before the current rules and regulations may have smaller septic tanks and may need to be pumped more often.

Cleaning the Tank

1. A septic tank pumper licensed by the Department of Environmental Quality (DEQ) can pump and clean your tank. It is a good idea to supervise the cleaning to ensure that is done properly. The material pumped out is known as "septage".
2. To get all of the material from the tank, the scum layer must be broken up and the sludge layers stirred up into the liquid portion of the tank. This is usually done by pumping liquid from the tank and reinjecting it into the bottom of the tank. The septic tank should be pumped out through the large central service hole, not the sanitary tee or baffle inspection ports. Pumping out a tank through the inspection ports can cause damage.
3. Before closing the tank, check the condition of the tees or baffles. If they are missing or deteriorated, replace them with sanitary tees. Never enter a septic tank. Any work to replace the baffles or repair the tank should be made from the outside. The septic tank produces toxic gases which can kill a person in a matter of minutes. 
4. When working on a tank from the outside, make sure the area is well ventilated and someone is standing by. Never go into a septic tank to retrieve someone who was overcome by toxic gases or the lack of oxygen without a self-contained breathing apparatus. In the event someone falls into a septic tank the best thing to do is call for emergency service and put a fan at the top of the tank to blow in fresh air.
5. To facilitate cleaning and inspection, install a watertight riser and a gasketed cover from the central service hole at least one inch above the surface before burying the tank. Do not bury the riser cover.

How to Get Further Information

Many counties administer the septic system program for DEQ. For further information on who to contact in a specific county or on DEQ's program, please contact the DEQ office nearest you or call toll free in Oregon 800-452-. People with hearing impairments may call DEQ's TTY at 503-229-.

Information in this handout was partially obtained through the Oregon State University Extension Service Circular, , January .

Septic Tanks That Don't Need Emptying

There are many myths surrounding septic tanks and sewage treatment plants. Being a subject that people don't necessarily want to talk about, confusion can often set in and misconceptions arise. We have put together a few myths and facts to keep you in the know about your septic tank.

1. You don't really need to do anything with your septic tank once it is installed.

Unfortunately this is not true - Your septic tank needs emptying regularly to remove the settled solids, preventing them from moving through the system. Bacterial treatment also helps to improve and maintain the levels of bacteria within the tank.

If you are looking for more details, kindly visit zhaoyang.

2. You aren't allowed to use any chemicals or cleaning products in your septic tank.

The thought here is that chemicals will kill the bacteria however certain chemicals and detergents can be used safely. Try to use laundry and dishwasher soaps that have low or no phosphate in them. Bleach and disinfectants can kill the bacteria in the tank so use sparingly and in small amounts. Or, septic treatment like our Biotreat365 microbial formula, can help to replenish bacteria lost through overuse of chemicals.

3. I only need to empty my tank when it is full

Again this is incorrect - The rate at which your septic tank needs emptying can vary depending on how many people live in your household, and the size of your tank, but The Environment Agency recommends that household septic tanks are emptied at least once per year.

The tank fills to working level within a few days after the emptying takes place and once it has reached its working level, it works by displacement &#; catching the solids as they enter the tank and allowing the dirty water to move through the system into the outlet &#; usually a soak-away or drainage field. The tank needs emptying regularly to remove the solids and prevent them from moving through into the outlet.

4. Some people never empty their septic tank and their system is fine

You might not be able to see the damage you are causing if you don't empty your septic tank but that doesn't mean it's not happening.

If the tank is not emptied the drain field or soak-away is likely to fill with sludge, which can reduce its effectiveness and can lead to a system failure. It can take several years for the effects of the damage to be seen, but the ultimate cost of repairs usually far outweighs the cost of the regular emptying, not to mention the disruption of having ground works carried out in the garden.

5. I have a sewage treatment plant so I don't need to empty it, as it digests all the solids by itself

All sewage treatment plants need emptying and servicing at regular intervals although the interval will depend on the size of the plant, and the usage.

Treatment plants rely upon settled solids being removed periodically. They then treat the dirty water that moves through the system, normally by means of aeration. Leaving a treatment plant without emptying for too long allows the sludge to move through into parts of the plant that it shouldn't reach, and even beyond into the outlet. This can cause damage to the component parts of the treatment plant and cause pollution to the area where the plant discharges.

Now that you know what's true and what's not, you need to ensure that you take care of your septic tank and have it regularly maintained and emptied. If you require any help with your waste management then give our team a call now on 455.

If you are looking for more details, kindly visit Wastewater Treatment Tanks.