How Do Bio-Gills Work?
Bio-gills offer more efficient aeration of organic material in the waste stream and very efficient biomass retention. This is achieved by using a unique membrane that is folded to form a series of “gills”. Each gill comprises a pair of folded sheets with a liquid stream sandwiched between them. Wastewater trickles down between the gills which are surrounded by air. Oxygen diffuses through the gills, feeding the microbes which oxidise the nutrients and changing them into biomass. Suspended solids stick to the biofilms on the insides of the gills which provide an extra cleaning function. The biofilms peel off the gills as large sheets which settle very quickly for easy removal. This prevents the gills from ever fouling and keeps the biomass fresh and healthy. The simultaneous aeration with settling in the decant tank below allows for extremely efficient removal of suspended solids, so filtration is not needed, with effluent containing only 1.0-2.0 mg/L of suspended solids. The bio-gills are durable, reliable, ultra-porous, extremely strong and non-biodegradable. Bio-gills have a major advantage over existing wastewater treatment processes because they do not rely on large amounts of expensive energy to oxygenate the water. With this technology the water trickles along the gills, so it does not need expensive and unreliable blowers or diaphragm pumps to compress air. Bio-gill technology does not rely on filters, which can be very expensive and tend to foul with only small volumes of oil or surfactant. Bio Gill Diagram. Please install the free Flash Player to view the animated diagram.
Bio-gill Advantages:
With energy consumption being minimal, membranes last in excess of 10 years and cost a fraction of MBR membranes to replace. Our bio-gill 20 kilolitre per day grey water system offers signifi cant fi nancial savings with a real return on investment. Our larger systems pay for themselves even more quickly, as the economy of scale reduces the capital and running costs. |
Small scale reuse systems such as decentralised grey water treatment systems (20 kL/day) uses 0.60 kilowatt hours of energy per kilolitre of water treated. For larger systems, energy consumption could be reduced by a further 75 percent, resulting in energy usage of 0.15 kilowatt hours of energy per kilolitre of water treated.
In the USA about 4 percent of electricity generation is used to move and treat water and wastewater, so the bio-gill technology will be capable of making a significant reduction in carbon emissions due to its low energy requirements.
For further information: http://css.snre.umich.edu/css_doc/CSS04-14.pdf
Bio-gills are extremely reliable because the system creates a habitat that is ideal for microbes to grow, so they rapidly consume nutrients and can adapt to change without requiring ramp-up.
Our bio-gills never foul, as the water does not pass through them. Instead, the nutrients pass through them.
Fouling of existing filtration membranes (MBRs) can cost more over the life of the system than the system itself. Membrane fouling has led to the decommissioning of many water reuse systems in Australia, as the membranes often last only six months and cost as much as 25 percent of the initial capital to replace.
Very stringent testing and control of the influent to prevent contamination of the membranes by oil or surfactants is essential for MBRs to last their specified life, as well as frequent cleaning and disinfection with a variety of chemicals.
On the other hand, bio-gills effectively treat oil and surfactant. We have operated systems on grey water (BOD = 70-190 mg/L), surfactant manufacturer wastewater (BOD = 42,000-110,000 mg/L ) and grease-trap wastewater (BOD = 5,500-20,000 mg/L) without fouling.
Long system life with very low maintenance
Aeration and settling occur concurrently, so suspended solids are easily removed with water treated to class A standard without the need for filtration. Other systems cannot remove sufficient suspended solids with gravity alone, so they depend on filtration that creates a fundamental flaw, making them less reliable and very expensive to maintain.
No need for technical expertise to operate the system, as it is fully automated and nature continually optimises the system with old biomass being automatically removed and replaced with young, healthy biomass.
There are no issues with sludge age, as the sludge is disposed of quickly (average sludge age is 4 days, not 15 to 20 days), so it never develops problems such as sludge-cake build up. For example, a sludge cake from a municipal sewage treatment plant was run through a bio-gill system and it all settled within two hours.
Capital outlay for the bio-gill system is about 50 percent less than for existing MBR technology.
Safe and silent with little or no odour
Bio-gill technology emits virtually no aerosol that causes airborne biohazards. This makes our systems ideal for use in public areas and within food processing locations.
There is very low odour and, up close, the system smells earthy, not offensive.
Blowers or diaphragm pumps are not needed for aeration with the bio-gill system, resulting in reduced noise and energy use. The impeller pumps used in our systems are submersible, resulting in silent and economical running, along with increased reliability.
Bio-gills effectively turn “bad” water into “clean” water using very low energy consumption and with minimal environmental impact.
Sludge output from bio-gills can be used as an organic fertiliser and some influents can be utilised in a bio-gas system.