FREQUENTLY ASKED QUESTIONS

These are general statements, which refer to the entire Hybrid Toilet System range

1. HOW DOES THE SYSTEM WORK?
2. IS THIS SYSTEM LIKE A DRY COMPOSTING TOILET?
3. CAN GREY WATER BE ADDED TO THE UNIT?
4. WHAT WILL HAPPEN IF THE SYSTEM IS UNUSED?
5. DETAILED SYSTEM DESCRIPTION
6. CAN ANYONE TOUCH THE WASTE OR CAN ANYTHING GET IN?
7. WHAT WOULD HAPPEN IF THE UNIT WAS FLOODED?
8. DO THE UNITS SMELL?
9. CAN THE TOILET BE INSTALLED IN A NEW OR EXISTING DWELLING?
10. HOW DO I REMOVE RUBBISH FROM THE SYSTEM?
11. CAN I COMPLETELY BURY THE TANKS?
12. CAN THE SYSTEM BE INSTALLED ABOVE GROUND?
13. HOW DO I SIZE A UNIT?
14. HOW MUCH SLUDGE IS GENERATED BY ONE PERSON?
15. HOW IS THE SLUDGE REMOVED FROM THE UNIT?
16. DO I NEED A PLUMBER TO INSTALL THE UNIT?
17. CAN ADDITIVES BE INTRODUCED TO THE SYSTEM TO IMPROVE THE DIGESTION PROCESS?
18. CAN THE HYBRID TOILET SYSTEM HANDLE AN OVERLOAD?
19. HOW WILL THE HYBRID UNIT HANDLE HIGH HYDRAULIC LOADINGS?
20. WHAT WILL HAPPEN IF THE SYSTEM IS OVERLOADED CONTINUOUSLY?

1. HOW DOES THE SYSTEM WORK?

Simple system description.
In simple terms the system consists of a MicroFlushing or a non-flushing, drop toilet, feeding directly into a primary treatment tank filled with water, which then delivers via displacement, clarified effluent to the secondary treatment unit. On completion of treatment the effluent is then dispersed to ground via a gravel bed.

2. IS THIS SYSTEM LIKE A DRY COMPOSTING TOILET?

No, this is a wet system.
Upon installation the tanks are totally filled with water. The constant addition of waste to the system will result in a flow of treated effluent through and out of the system by displacement. If 10 litres went in, approx. 10 litres will be displaced through the unit.

3. CAN GREY WATER BE ADDED TO THE UNIT?

No, additional waste water.
The addition of extra loading from other sources into the hybrid unit is not recommended. The system is designed to operate around the volumes generated by the population using the system as a toilet only. Waste from hand washing facilities may be introduced at the effluent exit point of the unit. This would require an extension of the gravel bed to cope with the extra volume of water generated. This would be subject to approval by your local authority.

4. WHAT WILL HAPPEN IF THE SYSTEM IS UNUSED?

Evaporation.
Dependent upon certain environmental conditions a certain percentage of water could be evaporated out of the system. In periods of very low or no use, the level of evaporation may exceed the incoming volume.

Should the unit sit unused for a period of, for example three months, the liquid volume in the unit would drop. The amount of evaporation that will occur is entirely dependent upon the climatic conditions. Once the unit is in service again, the liquid level in the primary tank will rise until the tank is full and then flow through to fill the secondary tank over time, displacing well treated effluent into the gravel bed.

If the unit was unused for even longer periods, some water could be added to the system but would not be required unless the water level was extremely low. It is not necessary for the unit to always be entirely full, because treatment will still occur while there is waste to be digested. After a long no use period the system will restart upon the introduction of fresh waste.

5. DETAILED SYSTEM DESCRIPTION

Primary Tank (refer general arrangement drawing).
The process begins when the waste drops down the dropper tube into the primary tank. Due to the very small volumes entering the primary tank the detention time in the system is as long as 83 days or longer dependent upon usage.

This extended period of detention allows for very effective breakdown of the solids and very efficient settling and clarification to occur. The remaining undigested solids settle out to the bottom of the unit to form the sludge layer. As use continues, the sludge volume will increase until it begins to impact on the detention time of the effluent.

Dependent upon usage, it will normally be years for this level to be reached. This volume requirement and sludge level is established and controlled through the use of a sludge gauge, which is supplied with the unit. The management of the sludge is discussed in more detail in subsequent paragraphs. As in a normal septic tank this sludge is acted on and broken down by anaerobic bacteria.

Parasites
Another benefit of the long detention time is the containment of parasites in the primary sludge. Parasitic eggs have a settling rate in a column of water and these settling rates have been established by studies conducted by the World Bank. The detention time in the primary tank is long enough to capture the majority of these parasites thus creating a very efficient barrier against re-infestation.

Secondary Tank
The effluent that has entered from the primary tank is now directed along a very specific flow path. The design of the flow path is such that it eliminates the possibility of short-circuiting. The majority of the secondary tank and its in-built baffling system is filled with a polyethylene media which supplies an extremely high surface area to volume ratio.

This media has been designed specifically for this process and has a high void space design to prevent clogging. Loadings entering the secondary system are well below the anti-clogging maximums for gravel bed wetlands. It is designed to easily cater for the loading delivered from the primary tank with a high built in safety margin. This is of extreme importance, so as to ensure absolute minimum maintenance, if at all.

Secondary Tank Flow Documentation
Another feature of this area is the unique flow path that the effluent must follow. Upon entering the secondary tank, the effluent is introduced into a series of descending, ascending and circular flow paths. The effluent must also travel through the extremely intricate flow path created by the plastic media, which guarantees maximum diffusion and mixing. This intricate and very specific flow path ensures that the effluent is in maximum contact with the bio-film at all times. This large contact area and long contact time allows for attacking of the remaining pathogens in the system by the bio-film bacteria.

As the effluent flows up and down through these zones it is also subjected to aerobic, facultative, and anaerobic treatment zones on four separate occasions which will also contribute to the kill rate of the pathogens. When the treated effluent completes this process it then exits the system and is sent to ground via a gravel bed. Because of the very small volumes of liquid and the quality of the effluent exiting the unit there is minimal impact on the surrounding environment. This then completes the treatment process.

6. CAN ANYONE TOUCH THE WASTE OR CAN ANYTHING GET IN?

No, this is a closed system.
At no stage during the process is the effluent exposed to human contact. The system is sealed with the only access being the waste delivery point and the vent. The system is designed to function in a high water table area with the secondary tank outlet above ground level. The system is not designed to be buried, as this would allow entry of unwanted extra water into the treatment zone. The closed system also prevents clogging from occurring by plant root intrusion, excessive algae growth, and insect infestation.

7. WHAT WOULD HAPPEN IF THE UNIT WAS FLOODED?

Flooding.
Should the unit become inundated by water the air space of the tanks will completely fill. As the flood waters recede below the outlet point and presuming the unit is still intact, the extra liquid will drain out and the unit would be immediately useable.

8. DO THE UNITS SMELL?

The MicroFlush unit has an inbuilt 5mm deep waterseal created by a counterweighted Stainless Steel flap.
This effectively stops any air flow coming back into the toilet bowl. A rotary ventilator is installed on the vent pipe to create a small negative pressure.
The NonFlush unit is also a closed system that allows for very specific control of air movement. Fresh air is continuously drawn down the toilet opening ensuring that any odor generated is expelled out the vent pipe. Remote applications are supplied with a solar panel, 12 volt fan and battery backup arrangement. For installations in domestic dwellings, we supply a small low voltage fan which is designed for continuous operation. This could be either mains powered or solar with battery back up.
Strong odor emanating from the vent pipe is an indicator of an imbalance in the system. See the information on additives in section 18.

9. CAN THE TOILET BE INSTALLED IN A NEW OR EXISTING DWELLING?

Yes.
As long as there is sufficient height under the floor of the building the unit can be retrofitted to an existing building. For actual height requirements, please contact your nearest agent and ask for General Arrangement Drawings for the system size your require. Excavation depth and width requirements will also be needed for correct assembly of the unit.
For new dwellings, please contact your nearest agent for General Arrangement Drawings for the appropriate system size.

10. HOW DO I REMOVE RUBBISH FROM THE SYSTEM?

Maintenance Access.
Access is provided in both the primary and the secondary tanks. The main access points are in the primary tank. These hatches are where the removal of the sludge takes place and removal of any foreign objects that have been placed in the unit. Flooding of the primary tank, due to a blockage is nearly impossible due to the design of the outlet junction and baffle. See drawings for details.
The MicroFlush option limits the introduction of foreign waste into the units.

11. CAN I COMPLETELY BURY THE TANKS?

No, refer to tank installation.
We do not recommend burial of the tanks to a greater depth than shown on the general arrangement drawings. Burial of the tanks will allow intrusion of ground water into the unit. Consult the manufacturer for special circumstances.

12. CAN THE SYSTEM BE INSTALLED ABOVE GROUND?

Yes.
The primary tank may be placed on top of the ground or elevated on a platform, but as shown the secondary tank must be installed lower than the primary tank to allow for gravitational flow to occur from tank to tank.

13. How do I size a unit?

Unit Sizing.
When sizing a hybrid toilet unit refer primarily to the Hybrid Unit size calculator
This is the most accurate method of calculating unit sizing.  All unit sizing should be done in conjunction with trained Hybrid Toilet Representatives. The average person is not qualified to size waste treatment units.  Each individual site must be assessed on its on merits looking closely at the circumstances that surround that particular site only. There is no such thing as a generic sized unit.

Never under any circumstances take a yearly average figure and size the unit based on that information alone.

Things to consider.
Factors that must be considered when sizing a unit is the type of the clientele using the unit, the type of use of the system (eg. day use area, camping area and combined use), fluctuations in loading and temperature. The travel distance from staging points has a bearing on use rates as well. 

Growth rate Allowance.
Something that mostly is forgotten about or is not considered is the growth rate that may occur on the unit loading. Hybrid Toilet units properly installed will last for decades. Some areas like the World Heritage area of Fraser Island in Queensland are undergoing growth rates of around 5% per year. When this is calculated out over time the effect can be substantial. It may be appropriate to allow for say 10 years of growth and plan for additional systems or upgrades as you approach that length of time.

Capped Visitor numbers.
Where circumstances allow it is ideal if visitor numbers can be capped. Controlled visitor numbers allow for more accurate unit 
Size calculations to occur. If this is the case then there is no need to build in percentage growth figures. Capped visitor numbers allow planning of minimal impact on the site. 

Door Counters.
The utilisation of door counter systems allows the tracking of unit usage rates. These figures can be recorded on data bases and analysed against unit performance.

Unknowns Allowance.      
All the above points have potentially a significant bearing on the unit’s performance. It is prudent to allow for around 25% extra capacity when calculating a rating. The Hybrid Calculator does this automatically.  This gives an allowance for unknowns.

Unit size driver.
If you have a particular period of the year where visitor numbers peak for a couple of months, work on these figures only and discount the remainder.
This is particularly important as under sizing the unit capacity at the beginning can create long-term management and environmental problems.
Large short duration spikes measured in a couple of days only will have little effect. It does become significant when the loading stretches out past this period.

Ideally with a little forward planning Porta Loos or the like should be brought in to carry significant spikes for once off events.  

Decisions on unit sizing based on cost alone initially may seem prudent, but in the longer term the cost of an under capacity system will far outweigh the presumed initial cost saving.

14. HOW MUCH SLUDGE IS GENERATED BY ONE PERSON?

This is dependent on diet, cultural considerations, temperature, and many unknowns; hence fecal volumes may vary. The introduction of Biological additives will assist in controlling sludge volumes.

15. HOW IS THE SLUDGE REMOVED FROM THE UNIT?

Guidelines for sludge removal and disposal.
There are two options available for the removal of sludge and they are subject to local Authority and or the controlling Authority's approval. Generally, if access can be gained by a licensed waste removal contractor, sludge should be removed in this manner. If this is not possible due to remoteness of location or accessibility, consult your Approving Authority for their recommendation on sludge disposal.

In all cases the relevant approvals must be sought prior to the installation of the Hybrid Toilet System. Removal of waste by other than licensed persons in some states may be prohibited.

16. DO I NEED A PLUMBER TO INSTALL THE UNIT?

Yes.
Installation should be carried out by and under the supervision of licensed persons. If a licenced person is not available please consult with your agent.

17. CAN ADDITIVES BE INTRODUCED TO THE SYSTEM TO IMPROVE THE DIGESTION PROCESS?

Yes.
Investigation has shown that the addition of products such as Bio Magic and Bio Magic (available from your nearest Tradelink store) are beneficial.

These products offer benefits in terms of odour control, cleaning of the water column and long term control of sludge volumes. A small amount of these products used as part of the general cleaning process will assist in balancing the biological process of the system.
Lysofos has also been used with success.

18. CAN THE HYBRID TOILET SYSTEM HANDLE AN OVERLOAD?

Yes, overload situations.
A major criterion of the systems design, is that the unit must be able to accept fluctuating loadings, both hydraulic and organic. The environment in which some of the units will operate can be subject to highly variable loadings. For example, National Parks which can receive substantially higher visitations over weekends and holiday periods.

The exceptionally long detention time enables the system to buffer the high loads. However there is a point where effluent quality and system performance will begin to diminish. There is no substitute for correct unit sizing in the beginning.

19. HOW WILL THE HYBRID UNIT HANDLE HIGH HYDRAULIC LOADINGS?

System comparisons.
Unlike septic systems, which will deliver very high hydraulic loadings in an overload situation, the hydraulic loadings on the Hybrid Units are very small by comparison under the same conditions.

Unlike compost systems that rely on quite controlled moisture levels the Hybrid unit is designed for high liquid loadings. Being a wet system high liquid loadings are not of great significance.

20. WHAT WILL HAPPEN IF THE SYSTEM IS OVERLOADED CONTINUOUSLY?

Extreme overload situations.
Major overloading for long periods and continuous overloading will result in three main problems.

1. There will be a significant reduction in effluent quality.
2. There will be a major buildup of floating material on the surface of the primary tank resulting in waste backing up into the dropper tube.
3. There will be strong odour emanating from the unit.
   

In light of the above it should be clear that careful consideration needs to be given to the sizing of the unit in the design stages to ensure that all the benefits of the Hybrid Toilet System can be fully appreciated.