Online TOC of our UPW is 0.5 ppb. Where does it come from? For new FAB we target 0.1 ppb and we need this information for plant design.
All DOC (0.5 ppb) is from raw water and is classified as ”building blocks”. The anion filters (separate or part of MB) need better regeneration to prevent permanent release of building blocks.
We want to reclaim a production water. It should only contain IPA and ammonium, right?
Apart from IPA (1455 ppb C) and ammonium (45 ppb N) the water also contains traces of high-molecular weight biopolymers (45 ppb) which may reflect a bacterial issue.
After pre-concentration in a quartz rotary evaporator at 40°C (DOC-Labor) organic matter in UPWs can be characterised.
UPW 1 has a TOC-value of only 0.6 ppb. All organics can be related to NOM.
UPW 2 has a TOC-value of 5.2 ppb. Only 1.55 ppb can be related to NOM, the dominant part of TOC has to be related to synthetic organic matter (SOM). Most fractions contain organic bound nitrogen which suggests permanent leaching of anion resins.
With LC-OCD almost all water-soluble organic compounds can be quantified and characterised down to the ppb level (or sub-ppb level after pre-concentration).
TOC of polishing loop was 1310 ppt.
930 ppt was related to a leaching product (L2) and 380 ppt to urea. NOM was fully absent (elutes between 25 – 50 min).
The water was fed to an additional RO-unit. L2 was fully removed, urea in part.
TOC of this product water was only 0.077 ppb or 77 ppt.
The purest water we have measured to date. (duplicate measurements).