Specialists in on-site
Wastewater Treatment


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A Home Sewage Treatment Plant (HSTP) is similar to a Municipal Sewage Treatment Works, except that it is designed smaller to fit in your own back yard.

A HSTP can also be commonly referred to as an OSF, an onsite sewerage facility, aerobic wastewater treatment system (AWTS), aerobic wastewater treatment plant, wastewater treatment system, sewage treatment plant or sewage treatment system.

It uses the same proven treatment methods as the larger system to treat all the wastewater that flows from the toilets, baths and sinks. These include coarse filtration, pre-treatment, aeration, settling and disinfection. However, all the water that you use in your house is available to you to recycle and reuse, after it is treated, to irrigate your garden, not like the Municipal works where it is not. Most people would not realise that a home has its own HSTP because it is just like living in a home that has mains or Municipal sewer connected and gives you all of the advantages that this service provides.

A septic tank (system) is a method of wastewater treatment that utilises only anaerobic bacteria (bacteria not requiring oxygen to live) in the treatment or septic tank. The tank has no aeration and treats the wastewater to about 20% of the amount needed to render it harmless to the environment.

Septic tanks can be vulnerable to poor soil conditions (clay, sand etc) high water table, clogging of the drain lines, damage to the drain lines by vehicles, animals, trees etc and neglect by failure to regularly (at least every 3 years but preferably every year) pumping out the sludge and solids from the tank.

We will assess your property or existing system, and work out what is best suited at your home based on council requirement, health and safety and budget. We WILL NOT sell you something you do not need and our aim is to work together to achieve a wastewater solution for you and your family.

An activated sludge system is a form of secondary treatment that is used almost exclusively in Municipal or Commercial Sewage treatment systems because of its complex management problems, necessitating full time operation and management of various processes by positive human and mechanical intervention.

It is a process for treating sewage and industrial wastewaters using air and a biological floc composed of bacteria and protozoans.

Complex mathematical models are used to design the volume of inputs, the formation of the sludge, removal (wasting) of sludge, the maintenance of a healthy bacteria population and eradication of harmful bacteria such as filamentous bacterium. It is not a system that can be easily scaled down and successfully operated in a domestic situation.

A worm farm, when used in this form, as distinct from “worm farms” sold by hardware stores etc, is a method of sewage treatment that is carried out by the action of worms that live in the sewage treatment plant.

The homeowner is required to clean any sediment from inside the distribution pit, wearing protective gloves and bury 200mm below ground. Because the treatment method only partly removes the pollutants, the water pumped from the system must be discharged at least 200mm below ground in a trench system, a general requirement throughout Australia for Septic Tank Systems.

A sand filter is an additional treatment process fitted to a Septic Tank outlet to process the partially treated effluent from the Septic Tank.

It usually consists of up to 20 cubic metres of the correct type and grade of sand, which is placed in an excavation, usually sealed by an impervious plastic liner, that may be 2 metres wide, 10 metres long and 1 metre deep.

The effluent is fed into slotted plastic pipes laid flat in the top sand of the filter, where it percolates down through the sand media and is collected by a slotted pipe set in the base sand. Because the sand acts as a mechanical filter for non-treatable matter, the septic tank must be pumped regularly to ensure the sand media does not become blocked by solids flushed out of the septic tank.

The sand media cannot be backwashed or cleaned and must be removed and replaced by fresh sand at the end of the life of the sand media. In poorly designed or constructed systems, failure can occur in as little as 3 years or less. It is estimated that the average working life of a properly constructed septic tank sand filter system is approximately 8 to 9 years. Sand replacement costs – when they inevitably occur – are generally similar to the installation cost of the complete system some 9 or 10 years before.

The need to dig out the sand with a machine, load it into trucks, remove it to a noxious disposal site and bring back in several truckloads of fresh sand usually causes mild to severe damage to the now established property.

There are a number of factors you should take into account when choosing the right HSTP for your home. All systems must meet a standard requirement to be sold on the market. There are different levels of effluent quality that needs to be adhered to depending on the location of your property and also proximity to dams and watercourses. There are 4 recognised grades of wastewater in Australia:

  1. Primary Effluent – Septic Tanks – No real treatment of effluent
  2. Secondary Effluent
  3. Advanced Secondary Effluent
  4. Advanced Secondary with Nutrient Reduced Effluent

Numbers 2, 3 & 4 require treatment plants to achieve these higher grades of effluent. Below are the Australian and New Zealand (AS/NZS) Standards levels that are applied to the final effluent for classification of the Effluent Standard into the various categories. The lower the number, the better the quality, the less hazardous the water is and the lower the pollution risk it will be to the environment, your family, your pets and your neighbours.

We are lucky to have access to a whole range of these. Size, budget, access, space restrictions and personal preference all need to be taken into account when deciding on your HSTP. everGREEN wastewater can assist with giving you all the information you need to make this easy and trouble free. Check our testimonials to see how we have for others.

Along with a 15 year structural warranty on your HSTP, you will also receive a 2 year electrical component and pump warranty as well as a 12 month servicing warranty. With a strong, sturdy backing from our steadfast, local suppliers as well as a firm guarantee from us that we will cover all warranties fairly and honourably, you can be sure that your investment is in good hands.

YES!, All HSTP’s in Australia, as a condition of their State Accreditation Approval, are required to be serviced by a licenced service technician. The state you are in and the type of treatment system you purchase will determine the service cost and frequency.

When installing a new system your first 12 months servicing is free. You can expect to pay approximately $80.00 per service thereafter, depending on your location and the type of system you have installed.

All HSTP’s can only be serviced by registered, licensed wastewater service personnel.

Your service technician will tend and monitor your HSTP to ensure that it is always operating at peak performance, producing water that is returning to the environment as the cleanest and best quality water (effluent) that it can produce.

Most systems use the same amount of power as a standard 80 watt light bulb. A HSTP will not draw power anywhere near as significantly as a pool pump.

The systems that we recommend are amongst the most energy efficient available on the market, whilst also providing the cleanest and greenest outcome for your family.

It is a common myth that the air pump is overly noisy in a HSTP. The air pump is similar in sound to a small fish tank pump. Any vibration from the air pump can be simply mended with foam packing we have available.

A HSTP utilises naturally occurring bacteria to treat the wastewater you put into it. everGREEN wastewater recommend that you choose products that:

  1. are labelled septic tank or HSTP safe;
  2. do not contain bleach, chlorine or antibacterial agents; and
  3. contain low quantities of sodium and phosphorous.

You can still use strong bleach products and antibacterial agents (for nappy soaking, whites etc); just use them in a bucket and tip the remaining product out into an unused part of your garden. The same applies to harsh cleaning products that you may like to use to clean kitchen appliances and bench tops etc. Use paper toweling to clean up with and dispose of in the garbage.

NO! It is strongly advised that you don’t turn the system off when you are away from your home. This allows the system to run as normal and when you return, you will have a still thriving HSTP (not a smelly problem).

NO! As your technician will need access to the HSTP for servicing purposes, the top of the system shouldn’t be covered with anything. However mulch and small shrubs with a shallow non-intrusive root base can be placed around the HSTP. You are best advised to discuss this with your service technician before undertaking any landscaping directly adjacent to your HSTP!