What are the OxyMem cleaning and storage procedures?
Biofilm maintenance and control can be assisted and accomplished automatically by an optional "biofilm control" system.
Since the membrane is dense and has no pores, no special cleaning is required. Membranes are not subject to drying; they can be stored indoors, in dry conditions as long as they are protected from sunlight and physical damage.
Modules should be cleaned well prior to storage if they have already been in operational use.
If the aeration demand increases how will the oxygen transfer be maintained to prevent the system turning anaerobic?
As the load increases the oxygen supplied can be increased by increasing the airflow through the membranes. This results in an increase in overall oxygen concentration within the membranes resulting in increased performance instantaneously.
Alternatively in systems where there is a large variation in aeration demand, the Oxygen transfer rate could possibly be increased by increasing the % of oxygen in the air supplied . This may result in more kg of oxygen being transferred for a given membrane surface area.
How do you control the thickness of the biofilm?
OxyMem systems use a patented biofilm measurement technique, which determines an effective biofilm thickness on the membrane. When the control system determines that the biofilm has grown too thick for the treatment process required, the system takes steps to automatically remove the excess biofilm.
The frequency of cleaning is dependent on the growth rate of the biofilm and the nature of the treatment process, but can vary from once a day to ~10 times per day if biofilm is growing fast (eg. Industrial loads).
Self cleaning will typically last 1-5 mins in duration, so the energy burden us negligible.
How do you perform desludging?
Sludge is allowed to settle in the bottom of the tank in our OxyFILM arrangement. Removal of settled sludge from tanks is via well established engineering practices. Removal of sludge is not OxyMem's scope, though we can indeed assist with this.
Sludge is very settable with a concentration of up to 10g/l. In a Retrofit installation, the excess biofilm would form part of the MLSS and need not be removed close to the MABR unit (i.e. MLSS would travel downstream and follow existing process - no changes are required to the sludge removal system).
How do client's control sludge level within OxyFILM tanks?
The plant would need a sludge removal system built into the base of the tank, or operate with a sludge blanket and remove via pump or gravity head etc. Well established engineering practices can be used.
At what maximum temperature has the system been tested?
The system has been tested up to 30°C.
We can have the temperature up to 50°-69°C in summer, or for industrial water when the wastewater contains a high concentration of food residues.
If the temperature increases OTE may increase and activity and metabolism of bacteria changes.
Above 40°C, "typical" municipal wastewater bacteria stop working. ie. Biology will be affected before the MABR unit materials are affected by temperature.
How often is biofilm thickness measured?
Where installed, the frequency of biofilm measurement can be adjusted to site requirements.
A smart controller can be set up to maintain a desired biofilm thickness, varying rates of measurement and control based on historical data/trend data.
How do you control the amount of flow that is distributed to each process train?
For OxyFAS applications (where MLSS is present) it is best to ensure a homogeneous mix around the modules.
For OxyFILM, the flow to the unit may be sent to a splitter box which will divide the flow equally between the installed process trains.