RoClean L403 is a low pH liquid cleaner designed to remove metal foulants such as iron, manganese, and aluminium as well as calcium carbonate scale deposits from spiral wound polyamide and cellulose acetate elements.
RoClean L403 has been certified by NSF International under ANSI/NSF Standard 60 for use as an off-line cleaner in drinking water systems.
RoClean L403 offers an array of performance benefits:
- Compatible with all polyamide and cellulose acetate membranes.
- NSF Certified for use in RO systems producing drinking water.
- Contains a special blend of buffers, chelants, and reducing agents, to promote the dissolution of metal deposits.
- Superior results to generic citric and hydrochloric acid solutions.
- Highly buffered to resist pH changes during the cleaning process.
- Can be used in conjunction with other applicable cleaners to remove combination foulants.
- Temperature compensated to maintain optimum pH over a wide temperature range.
Below is a summary of the RoClean L403 cleaning guidelines. For detailed procedures, please consult the Avista technical bulletin entitled “Cleaning of Spiral Wound Membrane Systems“.
- Fill the cleaning tank to the desired volume with RO permeate or DI water. Heat the solution to the maximum acceptable temperature (see membrane manufacturer guidelines, or use 50°C) as this will dramatically increase the cleaning efficiency. Add sufficient RoClean L403 to create a 2% wt/wt solution if the fouling is moderate/severe or 1% if the fouling is mild. Recycle the solution through the cleaning tank to ensure adequate mixing.
- Recirculate the cleaning solution through each RO system stage, one at a time, for a minimum of 60 minutes at the flow rate recommended by the membrane manufacturer. If that rate is not known, use the guidelines listed below:
Element Diameter Flowrate per Vessel, gpm (m3/hr) 4″ 10 (2.4) 8″ 40 (9)
- If the membranes are heavily fouled and the recirculated cleaning solution becomes discolored or turbid, discard as much as 15% of the solution volume. Heavily fouled elements may also benefit from a soak period (up to 8 hours).
- Monitor the pH of the solution during the cleaning process. If the pH remains in the desired range of 3.5 and the solution is not turbid, it may be used to clean subsequent stages. In the unlikely event that the pH rises above 3.5, prepare a new batch and repeat steps 1-4.
- When the clean is completed, rinse the membranes by recirculating RO permeate through each pressure vessel. To comply with NSF standards, the cleaner should be flushed with 5 bed/volumes of water before putting the system back on-line.