The contaminated water treatment system at the plant has been in operation since June 17, and it has been plagued with problems, most of which are blamed on the workers.
When they blame "worker's mistake" as the reason for system malfunction or breakage, suspect some other reasons that they want to hide. This seems to be the case for the troubles at the contaminated water treatment system.
The author of the following tweets seems to be one of the workers at Fukushima I Nuclear Power Plant, and his tweets are considered very credible by many, though a few suspect him to be a TEPCO's shill (which I doubt).
His tweets from July 1, and he talks about the contaminated water treatment system, AREVA's in particular:
続き①：今日も昼間は動いてなかったよ。作業員のミスって報道だけどオイラは管理側のミスだって思うんだけど…。特に一期工事のｱﾚﾊﾞの装置は他の現場で使用してたのを解体して持って来たんだけど施工は日本人でやってるんだ。
The system was stopped during the day today [July 1]. It was reported as "due to a worker's mistake", but I think it's the management mistake. In particular, AREVA's system [that was built] in the 1st phase of construction came from the active processing plant somewhere, which they dismantled and brought to Fukushima. But it was set up here by the Japanese.
続き②：ｱﾚﾊﾞの装置はイタリア製で図面もイタリア語とフランス語が混じって書いてあるからわかりづらいし質問しても構造や細かい所は国家機密か企業秘密かしらないが教えてくれないんだ。購入した東電でさえわかんない事多いみたい。
AREVA's system was made in Italy. The drawings are in Italian and French, so it's hard to understand. When we ask questions on the structure in detail, they don't answer, because of national security or corporate security or whatever. TEPCO, who paid for the system, doesn't seem to know much either.
二期工事も始まってますがあまりにも作業の振り分けがおかしくて現場が混乱してるのが現状なのです。
The second phase of construction has started, but the reality is that we are very confused because the jobs are not being assigned properly.
He says the system is not working as well as they thought, and that it should have been set up by the French or Italians who are the most familiar with the system.
The last I heard about the contract between TEPCO and AREVA (I also read somewhere later that there is no signed contract), even TEPCO didn't know what nuclides that AREVA's system would remove. Matsumoto of TEPCO said it was a corporate secret at AREVA and not to be disclosed.