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Please see below FAQs that can start to go on the site. We are speaking to our servicing department to come up with a good list of questions to then upload.

1. Do I need to empty it? If so, how often and who does it? How do I know when it needs emptying?

Yes, wastewater treatment needs to be emptied. The specific frequency will depend on the size of the treatment plant and the amount of wastewater entering it. If the wastewater treatment is sized correctly we would expect the system to be emptied between 6 to 18 months.

To know when it is the time to empty your treatment plant, you can use our maintenance kit or alternative methods. The kit contains a probe which will help you tell what the level of sludge is (deposit that needs to be pumped out). You can use the maintenance kit yourself (you will be provided with an instructions manual), or we can provide maintenance services. Once you have determined that it is time to empty your treatment plant, you can contract the services of a wastewater treatment specialist. Normally the treatment plant is emptied by a sucking or vacuum tanker that “sucks” out the content of your plant. The tank should then be refilled with clean water.

2. Does the system need maintenance/servicing? How often and who?

We recommend running a service/maintenance check for your wastewater treatment plant every 12 months. We are offering a maintenance kit that comes with an instruction manual, so you can do it yourself. However, we are offering maintenance services ourselves and we strongly recommend having a wastewater treatment specialist maintaining your system.

3. Who installs it? How is it installed?

The wastewater treatment systems that we offer, can be installed by anyone since complete installation instructions are provided upon purchase. However, we are generally doing the installation ourselves and we strongly recommend having a third party with the proper expertise doing it for you.

The wastewater treatment systems that we offer has two main parts: a tank and a compressor with a control unit.

To install the tank, you will need to dig a hole, fill the bottom of the hole with compacted and levelled pea shingle, lower the tank in, gradually fill the tank with water, while at the same time adding the backfill around the tank, until all the tank is covered. The water and the backfill should be kept at the same level.

The compressor and control unit are fitted together into a cabinet that can be placed next to the tank or in a shed or basement nearby. The unit will require access to a 230 V power source (normal 13 Amp power socket in a house).

There is also an inlet pipe that will be connected to your existing sewage network and an outlet pipe that will let the cleaned water flow into a drainage field or into a ditch or watercourse. Both pipes will be buried underground, except for the end of the outlet pipe if you are discharging the cleaned water into a ditch or watercourse.
The control unit and the tank are connected via 2-4 flexible PVC hoses which are housed into a plastic pipe that is buried underground. The system does not contain any moving parts inside the tank.

4. What is the warranty period?

The wastewater treatment systems that we provide have several components. The Carat tank has a 10 years warranty, while the cabinet (compressor and control panel) has a 3-year warranty. The warranty is and stays valid only if the system is installed, used and maintained properly, as specified in the provided manuals.

5. Does it need commissioning? By who?

We provide complete installation manuals with our wastewater systems that we provide. So, there is no specific need to get the installation commissioned by anyone if you install the systems yourself, according to the specifications provided. However, we strongly recommend having your system commissioned by one of our specialists to make sure the wastewater treatment plant will perform as specified in the certification.

6. How do I access the tank?

The tank can be accessed by the manhole situated on top of the tank. The green manhole cover that we provide will require a 17mm torque wrench or similar alternative to open the hatch. The cast iron lid provided for manholes installed under driveways will require a pair of lifting keys/hooks.

7. Who can install it? My plumber/builder/DIY?

If an installation is required, Graf can supply installation services. However, a third party (another company or even yourself) can be commissioned to install the systems. Upon purchase, we provide a full set of installation specifications and instructions for each component supplied.