New Developments in Water Reuse

IDE. Your Water Partners

Author & Presenter:
Dr. Boris Liberman
Membrane Technologies
View Presenter Biography


The Technology

  • Why is ultra-filtration post RO? Since the RO removes more bacteria than the ultra-filtration does, this step doesn't make sense.

Ultra-filtration is post RO in order to fulfill the log removal credit established by the health authority in the USA.

  • Why not use biological activated carbon (AC) instead of sand filters?

AC is a weak and more expensive material. It cannot be backwashed as effectively as sand. All the internal areas of the AC will be clogged, and stop taking any role in the work of the filter.

  • Don’t you get bacteria sloughing off of the sand filter into the RO?

Yes, bacteria will pass via the RO feed-brine channels, but we implement the DOHS process for bacteria dehydration.

  • Isn't there a danger of SO4-2 reduction to H2S (in the anoxic region of the biofilter)?

The filter operates in the presence of oxygen of at least 2ppm.

  • Why is anti-scalant dosed into the RO permeate, not into the RO feed?

This is a mistake in the drawing.

  • What about anaerobic fouling bacteria?

DOHS also dehydrates anaerobic bacteria.

The Results

  • Do you have data on bio fouling bacteria conc. comparing with FO+Micro pulses vs. FO only?

We have combined data at this stage. Our program includes the division of FO and Micro pulses activation, and we will publish this data.

  • Can we apply same on virus also???

I don’t know. I have not tested virus removal.

  • Boris, what is the impact of oscillation on on the life of membrane?

After one year of testing we have not seen any negative impact. We will continue to implement Micro pulses and will publish the outcome.

Overcoming Challenges

  • Dr. Liberman, I would be grateful if you could also explain about your experience in regards to high molecular weight polysaccarides/proteins removal by the IDE PROGREEN™ process upfront to the RO. I would expect your process to perhaps suffer from organic fouling due to the absence of coagulation and UF pretreatment. Thank you, Wolfgang Gernjak

There is intensive coagulation in WWRO IDE PROGREEN™, provided by the extracellular bacterial matrix that acts as a complex network that is secreted locally by, and remains closely associated with, cells. The extracellular bacterial matrix provides the adhesive for all colloidal material, as well as to that dissolved in WW organic material.

  • What is the concentration of the NaCl injected pulse to achieve enough FO effect?

The value has to be calculated according to RO train flow, pressure, and RO train configuration.

  • Hello, do these processes of forward osmosis cleaning and oscillation impact the warranty of the standard RO modules?

We tested the technological outcome of oscillation, and it does not have a negative impact on membrane performance. We will discuss the warranty issue with membrane manufacturers after presenting the pilot data from many plants to them.

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