How and when to empty your septic tank or sewage treatment plant

If you live in an area where there is no public main sewerage system then you will most likely have a house served by an off mains drainage systems. This is typically a septic tank, a low energy electric sewage treatment system or a non-electric sewage treatment plant.

With any type of septic tank or sewage treatment system you will eventually have to get it emptied. Getting a tank emptied only means removing the sludge that gradually builds up in the system over time, not all of the water. This sludge is formed by any large solids materials flushed down the toilet. We wont go into detail here but I am sure you get the general idea!

Sludge levels in your tank

When the sludge level builds up in a tank it reduces the available volume and space in the tank for the wastewater treatment process. So as the sludge builds up the system becomes less effective, and if a system is never desludged it will ultimately fail and cause problems.

Regardless of your location, there are septic tank emptying companies in every locality who will visit your site with a vacuum tanker truck. They will remove the sludge from your septic tank and take it away for disposal.

How often should I get my septic tank emptied

Sludge build up varies between systems. Many old fashioned three chamber systems or BAF systems produce very large amounts of sludge and require desludging as frequently as every 12 months. In contrast, systems like the Biocell QuickOne use an amazing treatment process that causes the sludge to break down. This results in tiny sludge volumes being generated with desludging intervals of >5 years being possible. Longer desludging intervals will save you money.

The only way to accurately determine the sludge level in your tank is to manually check the level. This can be done by dipping a piece of timber or a stick into the tank to see how deep the sludge blanket is. If the sludge blanket is >20% of the depth of the tank then you need to get it desludged.

Keeping a septic tank emptying log

If you are getting your tank emptied every few years then it is a very good idea to keep a log or record of the septic tank emptying intervals. This log, along with copies of receipts from the licensed waste collection company serves two purposes. Firstly, if you ever have a septic tank inspection then this will show the inspector that you are actively maintaining your system. Secondly, if you are ever selling your house then you can show this information to a potential purchaser and they will then know that you have properly maintained the tank.

Who to call to get your septic tank emptied?

When getting your septic tank emptied it is always a very good idea to ensure that you use a registered and licensed waste collection company. This means that the company is fully licensed and insured to handle the sludge. This sludge contains dangerous bacteria and must be properly handled and disposed of or it can cause a public health hazard.

You should never get a local farmer to collect this waste. If you get a local farmer to do this then there is a risk of large penalties and fines, as they are not trained to collect septic tank waste. Also, they will just end up mixing this with their other farm waste and slurry and then spreading it onĀ  their land posing a possible risk of groundwater pollution.

What happens to the sludge

Normally the septic tank emptying company will transport the sludge they have collected to the closest town or village wastewater treatment plant. The sludge will then be stored with the sludge generated from this large wastewater treatment plant. The local town or city council will then have a sludge management plan in place with the sludge being treated and processed and made safe prior to disposal or further use. Additional information on emptying for a homeowner can be found here.