Frequently Asked Questions

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At Harmor Waste Solutions we pride ouselves on being able to offer a range of services across a variety of industries. Should you need more information about any of our Services, read on to find questions and answers to the most popular Frequently Asked Questions. 

Frequently Asked Questions


Grease Trap Cleaning

What is grease trap cleaning?

A grease trap separates, and stores, the oils, fats and grease from the wastewater that comes from a kitchen. It filters the wastewater and prevents the oils and grease from entering a wastewater treatment plant.

How does grease trap cleaning work?

Waste water from your kitchen (drains, dishwashers and basins) enters the grease trap. As the wastewater cools, the fat, oil, and grease (FOG) hardens and the food solids settle. The FOG, being lighter than water, floats to the top of the grease trap. The wastewater then exits the grease trap and flows into the wastewater treatment plant. 

Why is grease trap cleaning needed?

Every restaurant serving any type of greasy food or baked goods (baked on premises) requires a grease trap to prevent blockages in sewer pipes, due to accumulated fat, oil, and grease (FOG) discharged from the kitchens of food facilities. If you don’t remove the FOG from your wastewater, you will, in effect, destroy the natural biological process that breaks down the solids in your sewage treatment plant.

Businesses that are on town sewage (ie. those that discharge to sewer instead of wastewater treatment plants), MUST have an agreement and a license with their local water authority to discharge their grease traps (trade waste) into the sewer network. The water authorities enforce the regular cleaning of grease traps by issuing harsh fines if businesses don’t comply, because it costs the authorities a lot of money to keep their pipes and treatment plants working effectively. 

So it doesn’t matter if your food business is connected to sewer, or not… it costs to maintain your grease trap, but the cost is well worth it in the long run.  

How do I know if my grease trap is the right size for my business?

Seating Capacity

Standard Grease Interceptor Sizes


600 Litre Grease Interceptor


1,100 Litre Grease Interceptor


2,000 Litre Grease Interceptor


3,000 Litre Grease Interceptor


4,000 Litre Grease Interceptor


5,000 Litre Grease Interceptor

How often should I empty my grease trap?

This varies from business to business and really depends on how much fat, oil, and grease (FOG) you put down your kitchen drains, together with how big your grease trap is. On average, grease traps are emptied between every 1 - 3 months. A helpful rule to live by is that a desludge (pump out) is due when one quarter (1/4) of your grease trap is filled with FOG. The technician cleaning your tank out will be able to provide the best advice on frequency of desludging. 

Regular cleaning of your grease trap is critically important as the FOG will destroy the natural biological process by killing off the good bacteria in your sewage treatment plant, therefore increasing the cost of repairs.

Do grease traps smell?

Yes, they do! They smell really bad! The primary cause of most grease trap odour is the decomposition of organic waste as it passes through your system. To help manage strong odours, you could try the following:

  • Increase the frequency of desludging your grease trap
  • Use bacterial additives that dose your drain lines
  • Check your lids to make sure they are sealed properly

What can I do to reduce the amount of fats, oils and grease going down the drain?

This is the most important question and can save you a lot of money if you stop the FOG from going down the drain in the first place. Please try and implement the following in your workplace:

  • Allow the grease to solidify and then throw in the bin
  • Clean dishes as much of as possible with a paper towel or cloth and dispose into the bin before washing in the sink or dishwasher (it’s often the little bits that build up and cause problems)
  • Ensure that all coffee cups are cleaned with a cloth prior to washing and NEVER pour milk down the drain.
  • Avoid pouring alcohol down the drain! It also has an adverse effect on the performance of the grease trap and sewage treatment plant.

What will happen if I don't desludge (pump out) my grease trap regularly?

If the FOG from your grease trap enters your wastewater treatment plant, it will not only destroy the natural biological process that breaks down the solids in your sewage treatment plant, but it may result in costly repairs to blocked sewer pipes, filters, irrigation pipes and failed pumps. 

If your treatment plant becomes contaminated with FOG, you will need to desludge your grease trap AND your whole wastewater treatment plant.

Please contact Harmor today if you need your grease trap pumped out. Harmor can also setup reccurring reminders to let you know when your grease trap is due to be desludged.


Septic Tank Cleaning (Desludging)

Why do I need to get my septic system desludged?

The wastewater (sewage or "blackwater") that enters your septic system from your home, includes a mix of inorganic and organic substances. Over time, this effluent settles out in the primary septic tank, with the solids settling on the bottom as a layer of sludge, the grease/scum floating to the top, and a central volume of liquid effluent and dissolved solids between these two layers.

Over time, the sludge and scum layers will build up in your system. When these layers reach more than two thirds of the total capacity, your tanks need to be desludged by an accredited liquid waste contractor. 

What could happen if I don't desludge my tank/s?

  1. It may cause blockages on the inlet of your system
  2. Raw sewage can overflow from the Over Relief Gully (ORG), which is the black grate near the edge of house
  3. High sludge and scum levels may cause:
    1. Poor performance of the septic system
    2. Blockages within the septic system and/or irrigation filters
    3. Blockages within irrigation areas / trenches, causing costly repairs to the irrigation field
    4. Bad odours
    5. Blockages of pumps, causing costly repairs

On average, a family of 3-5 people should have their septic system desludged every three years. 

My tanks are buried. Can I still get my system desludged?

Yes, you can. But we will need to expose the tanks before we can empty them. Additional costs may apply if we need to dig up tank and expose lids.

My tanks are located in an area that is not easily accessible. Can I still get them emptied?

Harmor Liquid Waste Solutions utilise a number of different sized trucks to cater for site access to all systems/properties, but we need to organise the right truck ahead of time, so please let us know when you call to book this in. 

If your system is more than 40 metres from where the truck can park, we will need to bring additional hose, which may incur an additional cost. 

What should I expect after desludging of my systems?

It usually takes up to three months for the system to re-establish the good bacteria and start producing clean odourless effluent. During this period, you may experience:

  1. Strong odours, especially during peak times such as showers and after loads of washing, etc
  2. Poor quality of treated effluent
  3. Service reports stating system poor performance

What important things do I need to do after a desludge?

  1. Avoid or reduce any harsh chemicals being poured down the drain
  2. Conserve water usage
  3. Prevent oils and grease from entering your system. Put them in the rubbish bin instead.
  4. Refill the system with water immediately. The water helps to give your system a head-start by diluting the wastewater that enters your system. Refilling with water will also ensure there is sufficient weight in the system to prevent the unlikely, but possible, situation of your tank/s lifting out of the ground, due to buoyancy from groundwater pressure. This is especially the case during wet weather or in high-water table areas, and especially for plastic tank systems. Be careful to closely monitor whilst refilling the system, don’t forget to turn off the tap. You can refill the system by putting hose through the septic access lid or down the ORG (100mm black grate on the outside of your house)
  5. Advise Harmor of the date of your desludge so we can update your records for future reference.
  6. Please note: Strong medications can also affect the re-establishment of good bacteria in your septic system. Contact Harmor if you would like more information about this.


Car Wash Cleaning

Why do I need to remove the liquid waste from my car wash?

The drainage and recycling systems of a car wash are designed to separate the pollutants from the water. 

Pollutants include:

  • Car washing chemicals used
  • Solids from cars (mud, dirt and road grime)

The pollutants collect in the collection pits of car wash bays and in the triple interceptor, prior to the water being recycled or going to sewer. Over time the collection pit drainage and triple interceptor fill with heavier solids/pollutants (build up). These are required (by trade waste agreements with water boards) to be emptied and treated at an EPA licenced facility.

How often do the pits and interceptors need to be emptied?

This is determined by the trade waste agreement that you need to have in place with your local water board.

What happens if I don’t empty my pits and inceptors?

You may damage your existing water recycling infrastructure. You may experience blockage of drains, causing flooding, resulting in bays being unusable and a high risk to safety and environment. 

How long does it take to empty?

This depends on the capacity of your infrastructure (ie number of litres) as well as other factors, such as the frequency of prior cleans, etc. The average time this takes is approx. 4 hours, but it can take up to one full day on rare occasions.  


Drain Cleaning

When would I need to unblock drains?

You may notice your sink or your toilet draining slowly, or you might hear a gurgling sound from your toilet. This indicates that your drains may be blocked. There may be a broken drain or a foreign item stuck in your drain. 

Water may start to pool/flood around forecourt collection pits or storm water drains or in car wash bays. 

Can I continue to use the drains while they are being emptied?

No, especially when operating CCTV in drains. 

How often should I clean my drains at home?

Typically people only get their drains cleaned when there is a blockage or the water is draining slowly. 

How often should I clean my drains at work?

Often commercial and industrial businesses that have high vehicle traffic, such as petrol stations, car washes, and fast food outlets require preventative maintenance for their drains to ensure there is no downtime onsite and/or restrictions to trade. This helps to avoid costly reactive repairs.


Fuel Interceptor

Why would I need my fuel interceptor serviced/cleaned?

There is a huge amount of small debris from the fuel forecourts e.g lolly wrappers, icypole sticks, etc., that can get into the fuel interceptor and block it up. Also, a build up of fuel and oil spillages from cars and trucks will build up in the interceptor.


Industrial Wash Water

Where would I find industrial wash water?

This comes from cleaning, rinsing or washing operations, such as car and truck washes and laundries. 

How often do the pits and interceptors need to be emptied?

This is determined by the trade waste agreement that you need to have in place with your local water board.


Emergency Repairs

Help! I have an emergency. Can Harmor help?

Harmor can be contacted and can attend to emergency callouts 24/7, 24 hours, seven days a week, 365 days a year.

My system is sounding an alarm and/or flashing red lights. What do I do?

Most types of wastewater treatment systems have a warning alarm function, which may be audible and /or flashing lights. These are not to be ignored. The alarm function is alerting you to a system fault which needs to be attended to as soon as possble. Please contact Harmor Liquid Waste Solutions as soon as you are alerted, so as to avoid any unneccesary complications brought about by leaving the problem to occur for too long. 

There is a foul odour coming from my system. What does this mean?

For correct functioning, wastewater tretment systems need to operate under alkaline conditions. Some factors which can cause acid conditions and odour problems include:

  • Excessive use of cleaning products
  • Use of the wrong type of cleaning chemicals
  • Shock volumes of incoming water (eg. from several loads of washing in quick succesion or a large number of people at a party)
  • Lack of use of the system while the house has been vacant (eg. unused holiday homes)

The normal (good) bacteria may die off under acid conditions resulting in offensive odours. It is quite simple to restore the balance using hydrated lime available from hardware stores. Following instructions on product packaging, and if odours persist or you have any questions, please contact Harmor Liquid Waste Solutions. You may also need to get your wastewater treatment system pumped out (desludged). 


Fuel Forecourts Cleaning

What do I do if I'm noticing a lot of debris and fuel/oil spillage in my fuel forecourt?

There is a huge amount of small debris from the fuel forecourts e.g. lolly wrappers, icypole sticks, etc., that can get into the fuel interceptor and block it up. Also, a build up of fuel and oil spillages from cars and trucks will build up in the interceptor. Contact Harmor Liquid Waste Solutions and we'll make a plan to clean and/or service the fuel forecourt and any associated equipment for you. 


Truck Hire

Do I need to have a truck licence to hire one of your trucks?

No, no truck licence is necessary as we do not hire the truck as a dry hire for you to drive yourself. All our trucks come with our experienced operators who do the driving and operating for you.