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What makes up a BioGill unit?Each BioGill treatment unit consists of the following components;
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BioGill capacity
The size of a standard BioGill treatment core for commercial purposes is 1300mm x 1300mm x 2300mm high. This treatment core can treat up to 20,000 litres of wastewater per day, depending on the influent composition and the level of treatment required.
How do BioGills work?
Wastewaters are transferred to the treatment tank. The gill recirculation pump then takes this wastewater to the top of the BioGill unit. The waste stream is then spread across the gill sets, via the water disperser. The nature of the gill sets allows for immediate dispersion throughout the system. Gravity moves the waste stream down through the unit and back into the treatment tank.
Along the Nano-Ceramic Membranes™, highly active and intense biomass consumes the nutrients from the waste stream during each pass of the wastewater.
The typical treatment cycle for the waste stream involves multiple passes of the liquid through the BioGills. The range of Biological Oxygen Demand (BOD) removal during a treatment cycle is between 90 - 99% depending on the makeup of the waste stream and average operating temperature.
What do BioGills treat?
BioGills house biomass cultures that effectively reduce carbon, nitrogen, sulphur, phosphorous and organic compounds. In particular, BioGills achieve high performance in the reduction of:
- Nitrogen
- BOD from high nutrient load waste streams
- FOGs (fats, oils and greases).
BioGills can also treat waste streams with wide pH parameters of between 4 and 9.5.
As BioGills are a liquid treatment system, the recommended particle size is 2mm or less in diameter. Therefore, pre-screening may be necessary on certain influent types to remove solid particles over this size. BioGills are resilient to reasonable amounts of detergents, soaps and cleaning products within the waste stream.
Important note: As with all biological treatment systems the performance of BioGills is retarded by any sanitising components within the waste stream, such as biocides (including So2 and very high conctrates of disinfectant).
In addition BioGills do not remove non-organic materials including salts, minerals and heavy metals, although such compounds do not damage the treatment cores.
Small amounts of petro-carbons, oils and grease can be effectively removed. Research is now underway to significantly improve the removal rate of petro-carbons from waste streams using BioGill technology.
Operating environments
The ideal operating range for a BioGill system is between 15 - 50 degrees Celsius. Below 15 degrees Celcius the system begins to “slow-down”. The temperature within the BioGill unit will depend on both the ambient and influent temperature.
BioGills can be effectively insulated from the outside air temperature. The internal temperature is somewhat self-regulated and depends on the nature of the influent.
Key system design features
1. Sludge removal
Sludge is created through two forms in the BioGill system, namely dead biomass and non-consumed solid particles. Sludge in a BioGill system is minimised through cannibalisation during the treatment cycle. However, sludge build up will occur over time and needs to be managed via sludge pump removals.
2. Flow rate
The flow rate of the pump to recirculate the wastewater through the gill sets is determined by:
- the treatment volume
- divided by the treatment cycle time
- multiplied by the predetermined treatment index.
3. Settling stage
Settling is an important stage of the BioGill treatment cycle. At the end of the pumping recirculation stage, high levels of oxygen and low levels of nitrogen are contained within the treatment tank. Settling of suspended solids is achieved during this period. Following this stage, treated wastewater can be transferred for disposal or reuse.
4. Treatment cycle time
Treatment time depends on the waste production cycle, the nutrient loading of the waste stream, the Nano-Ceramic Membrane™ area in use and the discharge requirements. In standard systems a treatment cycle is generally run over 24 hours. This can be significantly increased or reduced as required by the project’s specifications.
5. Control and monitoring systems
With each BioGill system the hydraulic flow rates are managed by a program logic control. This can be upgraded to include an alarm and monitoring system.
6. Disinfection system
If the discharge is to be reused and therefore involve human contact, the water will need to be passed through a disinfection stage. As BioGills are so effective at removing BOD and suspended solids, the disinfection stage is highly efficient and usually involves hypochloride dosing or UV sterilisation.
How do you start a BioGill system?
BioGills are a self-optimising system in that the microbes most suited to consuming the waste steam will be become dominant within the BioGill core. In many instances these naturally occurring microbes are within the waste stream.
However, for quick start up, systems can be seeded with inoculates.
