Septic tanks contain a population of bacteria that breaks down and digests household wastewater. Solid waste sinks to the bottom of the tank while fats and grease float to the top. An outlet baffle prevents sludge and scum from exiting the tank with the wastewater.

The resulting liquid, known as effluent, seeps through the drain field or absorption field (also called the leach field) into groundwater. Excessive rainfall or rapid snowmelt can waterlog the drain field and prevent it from operating normally. Click the https://www.septictankarmadale.com.au/ to learn more.

A septic tank holds wastewater for a time in order to allow solid waste to sink and decompose. Bacteria in the septic tank work to break down this material, with heavier solids (like sludge) sinking to the bottom while oils and grease float to the top. When this process is complete, wastewater leaves the tank through an outlet pipe. A filter may be installed in the outlet pipe to prevent large particles from entering the drain field.

A drain field, also called an absorption field or leach field, is a network of perforated pipes buried in gravel trenches. These pipes extend to the soil below, where water is absorbed by the surrounding grass and groundwater or surface water.

In a traditional system, the partially treated wastewater moves out of the septic tank into a distribution box. From here it flows through a series of perforated pipes into the absorption field.

This system is more effective than a septic tank in areas with high water tables or poor drainage, since it allows for the natural purification of wastewater through the soil and groundwater. It is also more cost-effective for homeowners with small households, as it doesn’t require the same emptying frequency as a septic tank does.

Keeping a septic tank properly maintained is key to avoiding costly repairs. Homeowners should have their tanks pumped every 3 to 5 years, according to manufacturer instructions. In addition, they should avoid flushing non-septic-safe items down drains and toilets. This includes wipes, paper towels, pet poop and other things that are often advertised as “flushable.”

A well-maintained septic tank will have an inlet baffle wall, an outlet baffle and a filter to prevent sludge or scum from leaving the tank. This keeps these materials from clogging the outlet or drain field, which can lead to sewage backups. It’s also important to plant vegetation that is shallow-rooted, like grass, around the absorption field. Deep-rooted plants and trees can grow into or around septic tank and drain field pipes and clog them. Inspect the septic tank and drain field for cracks, leaking or damaged parts and replace any as needed.

Sludge

In the septic tank, wastewater is separated by both settling and flotation. Solids that are lighter than water (oil, grease, and soap scum) float to the top of the septic tank. Aerobic bacteria break down floating solids in this layer, resulting in a clear liquid called effluent.

In contrast, solids that are denser than water form a thicker layer called sludge along the tank bottom. Underwater anaerobic bacteria consume organic materials in the sludge layer and produce methane and carbon dioxide as a byproduct. This process creates a sludge layer that eventually sinks to the bottom of the septic tank.

The septic tank is designed to allow for a certain amount of sludge accumulation before it needs to be pumped. The actual amount of accumulated sludge depends on the number of people living in the home and the types of items being flushed down the drains.

For example, avoiding the use of chemical cleaning products or washing laundry with fabric softeners can help keep the sludge level down in your septic system. Similarly, avoiding flushing non-biodegradable materials down the toilet like plastic objects, coffee grounds, food scraps, paint, solvents, insect killers, and medicines can also help minimize sludge buildup.

To check your septic tank sludge level, wrap a white rag or old towel around the bottom three feet of a stick at least six feet long and fasten it with tape or string. Carefully lower the stick into your septic tank’s first compartment. Then, look for a distinct dark stain on the towel representing the sludge layer. Then, mark the stick at a reference point to indicate the bottom of the tank’s outlet baffle or through the septic tank’s outlet tee. With the tank’s lids removed, remove the stick carefully and lay it beside the sludge stick for comparison. A difference between the two marks indicates the sludge layer is growing in your septic tank and you need to have it pumped. If left unattended, septic tank sludge buildup can lead to reduced tank capacity, clogged drain fields, and environmental hazards. Therefore, it’s important to have your septic tank regularly inspected and pumped as recommended by your local septic system professional.

Scum

Unlike sludge, the scum layer is made of things that rise to the surface in wastewater, such as soap byproducts and grease. The scum layer can sometimes be thin and easily separated from the wastewater, but it may also become thicker than usual due to improper plumbing.

When there is a lot of scum in the septic tank, it can cause a lot of problems. It can lead to the failure of a septic system, which can result in expensive repairs or replacement parts. It can also contribute to the clogging of drainfield gravel, which will lead to poor drainage and pathogenic bacteria. It’s important to have the septic tank pumped out as soon as possible when the scum layer starts to become too thick.

The septic tank is designed to have enough volume to store sludge and scum for an extended period of time, but the rate at which solids accumulate will vary from one home to the next. As a general rule, one-half to two-thirds of the tank’s volume is reserved for sludge and scum storage.

Septic tanks work thanks to bacteria, which help dissolve and break down the solid waste in the septic tank. The bacteria then turns the wastewater into a liquid substance called effluent, which is released into the drain field. If there isn’t enough bacteria in the septic tank, it can take much longer for wastewater to be fully treated and discharged from the system.

It’s important to understand that a septic tank should always have three distinct layers, including a scum layer at the top, a sludge layer in the middle, and clarified effluent at the bottom. When there aren’t any of these layers present, it means that something is wrong with the septic tank and needs to be inspected immediately.

There are many products on the market that claim to help with septic tank maintenance, but they can actually do more harm than good. These chemical additives can kill the bacteria in your septic tank and can seep into groundwater. They can also contain protozoa, which are single-celled microorganisms that eat away at organic materials. They can also clog the tank’s drainfield and cause wastewater to back up into the house.

Gases

Septic tanks are confined environments that produce sewer gases which can poison people if inhaled in high concentrations for prolonged periods. In such cases, people can suffer hypoxic damage to the vital organs of their bodies. This is a very serious condition that can be fatal if left untreated.

These gases are produced by the decomposition of organic waste in an anaerobic environment. As a result, they are highly toxic and explosive, making septic tank handling extremely hazardous. Sewer gas poisoning may lead to death in a matter of minutes if someone is exposed to high concentrations for long periods. The toxins can also cause permanent damage to the lungs and brain, which makes it impossible for a person to breathe.

When the septic tank fills up with organic waste, it turns into an oxygen-deficient space. As a result, methane, a toxic and flammable gas, builds up inside the tank. Methane can kill a person in seconds if it is inhaled for long periods.

Other byproducts of the anaerobic digestion include hydrogen sulfide ceH2S and ammonia ceNH3, which both have pungent smells. When H2S is deposited on a moist surface, it converts to sulphuric acid. Hydrogen sulphide is also toxic when deposited on concrete surfaces. It eats away at the concrete and can render it structurally unsafe.

In addition to methane, septic tanks emit other GHGs such as carbon dioxide (CO2) and nitrous oxides. Nitrous oxides are very potent greenhouse gases with a global warming potential that is more than 100 times greater than CO2. Methane, nitrous oxides, and CO2 can also accumulate in the atmosphere and be transported to other countries, contributing to climate change.

To monitor the emission of GHGs from septic tanks, we tested the first compartment of ST1-ST10 septic tanks with a dissolved oxygen (DO) sensor and an oxidation-reduction potential (ORP) sensor. We also collected septage samples from each septic tank and analyzed them for the composition of organic pollutants. Our results showed that septic tank conditions (ORP, BOD mass, and COD mass) significantly influenced CH4 emissions from the first compartment of septic tanks.