## 4 Discussion
The basic mechanism of DOC and inorganic solute accumulation in the residual fluid during ice formation in the reactor is simply a physically induced increase in their concentration  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{**Freezing WSL + F WSL + BZT (Insulant + No Insulant)**} & \multicolumn{6}{c}{**Thawing WSL + F WSL + BZT**} \\ \hline  & **DOC** & **Na** & **Al** & **Ca** & **Fe** & & **DOC** & **Na** & **Al** & **Ca** & **Fe** \\ \hline DOC & 1 & \(-\)0.4156 & 0.5072 & 0.0843 & 0.5100 & DOC & 1 & \(-\)0.3016 & 0.5712 & 0.1688 & 0.6304 \\ Li & \(-\)0.1530 & 0.7967 \({}^{*}\) & 0.4767 & 0.7761 \({}^{*}\) & 0.4696 & Li & 0.2761 & \(-\)0.0676 & 0.4645 & 0.3155 & 0.3766 \\ B & \(-\)0.0739 & 0.6382 & 0.0415 & 0.6214 & 0.1158 & B & \(-\)0.0679 & 0.9436 \({}^{*}\) & \(-\)0.0395 & 0.7411 \({}^{*}\) & 0.1240 \\ Na & \(-\)0.4156 & 1 & 0.1041 & 0.7425 \({}^{*}\) & 0.1953 & Na & \(-\)0.3016 & 1 & \(-\)0.1697 & 0.5711 \({}^{*}\) & 0.0609 \\ Mg & \(-\)0.2679 & 0.8074 \({}^{*}\) & 0.1838 & 0.7995 \({}^{*}\) & 0.1953 & Mg & \(-\)0.2314 & \(-\)0.0126 & \(-\)0.1526 & \(-\)0.7061 & \(-\)0.2045 \\ Al & 0.5072 & 0.1041 & 1 & 0.2329 & 0.7560 \({}^{*}\) & Al & 0.5712 & \(-\)0.1697 & 1 & 0.2742 & 0.9317 \({}^{*}\) \\ Si & 0.1082 & 0.4472 & 0.5676 & 0.3854 & 0.8156 \({}^{*}\) & Si & 0.2021 & \(-\)0.1342 & 0.4378 & \(-\)0.4496 & 0.3752 \\ P & 0.1482 & 0.4320 & 0.2525 & 0.7756 \({}^{*}\) & 0.5143 & P & 0.7269 \({}^{*}\) & \(-\)0.3039 & 0.4626 & 0.2122 & 0.4140 \\ K & \(-\)0.0056 & 0.3047 & 0.6187 & 0.2150 & 0.4870 & K & \(-\)0.2479 & \(-\)0.0247 & 0.3868 & \(-\)0.2146 & 0.2404 \\ Ca & 0.0843 & 0.7425 \({}^{*}\) & 0.2329 & 1 & 0.3776 & Ca & 0.1688 & 0.5711 & 0.2742 & 1 & 0.4163 \\ Ti & 0.5325 & 0.1927 & 0.7393 \({}^{*}\) & 0.3701 & 0.8923 \({}^{*}\) & Ti & 0.4915 & \(-\)0.0464 & 0.7842 \({}^{*}\) & 0.4037 & 0.8648 \({}^{*}\) \\ V & 0.7352 \({}^{*}\) & \(-\)0.1233 & 0.4677 & 0.3208 & 0.7364 \({}^{*}\) & V & 0.5676 & 0.0204 & 0.8124 \({}^{*}\) & 0.6671 & 0.9248 \({}^{*}\) \\ Cr & 0.3214 & \(-\)0.2685 & 0.3539 & \(-\)0.1761 & \(-\)0.1111 & Cr & 0.1342 & 0.0799 & 0.0982 & 0.2944 & 0.0721 \\ Mn & \(-\)0.0527 & \(-\)0.1320 & 0.4663 & \(-\)0.3944 & 0.1574 & Mn & \(-\)0.2300 & 0.4363 & 0.4854 & 0.2417 & 0.5073 \\ Fe & 0.5100 & 0.1953 & 0.7560 \({}^{*}\) & 0.3776 & 1 & Fe & 0.6304 & \(-\)0.0609 & 0.9317 \({}^{*}\) & 0.4163 & 1 \\ Co & 0.0272 & 0.4662 & 0.7655 \({}^{*}\) & 0.2426 & 0.5674 & Co & \(-\)0.1855 & 0.0481 & 0.5476 & \(-\)0.0876 & 0.4929 \\ Ni & 0.0342 & \(-\)0.3260 & \(-\)0.2851 & \(-\)0.2410 & \(-\)0.0968 & Ni & 0.6660 & \(-\)0.0068 & 0.6953 & 0.3143 & 0.8425 \({}^{*}\) \\ Cu & \(-\)0.1651 & 0.3935 & 0.5024 & 0.1072 & 0.6297 & Cu & 0.2010 & \(-\)0.1413 & 0.2787 & 0.1113 & 0.1933 \\ Zn & \(-\)0.1390 & 0.0970 & 0.2811 & \(-\)0.2016 & 0.1828 & Zn & \(-\)0.4330 & 0.1063 & \(-\)0.1833 & \(-\)0.6541 & \(-\)0.2768 \\ Ga & 0.5550 & \(-\)0.2729 & 0.4173 & 0.0082 & 0.0492 & Ga & 0.5962 & \(-\)0.2789 & 0.5572 & \(-\)0.0347 & 0.4060 \\ As & 0.7066 \({}^{*}\) & \(-\)0.0685 & 0.3519 & 0.3874 & 0.6971 & As & 0.5922 & \(-\)0.0274 & 0.8507 \({}^{*}\) & 0.5036 & 0.8904 \({}^{*}\) \\ Rb & 0.2731 & \(-\)0.1322 & 0.6126 & \(-\)0.0054 & 0.3259 & Rb & 0.5634 & \(-\)0.3121 & 0.9508 \({}^{*}\) & 0.1782 & 0.8402 \({}^{*}\) \\ Sr & \(-\)0.1735 & 0.7653 \({}^{*}\) & 0.2376 & 0.8512 \({}^{*}\) & 0.2824 & Sr & \(-\)0.2950 & \(-\)0.0756 & 0.1700 & \(-\)0.3811 & \(-\)0.0417 \\ Y & 0.1877 & 0.1517 & 0.5959 & 0.1345 & 0.6976 & Y & 0.5229 & 0.0566 & 0.9368 \({}^{*}\) & 0.3604 & 0.9358 \({}^{*}\) \\ Zr & 0.33388 & \(-\)0.0874 & 0.4281 & 0.0913 & 0.3792 & Zr & 0.6300 & \(-\)0.0906 & 0.9480 \({}^{*}\) & 0.4148 & 0.9705 \({}^{*}\) \\ Nb & 0.0318 & 0.5789 & 0.7029 \({}^{*}\) & 0.4167 & 0.7073 \({}^{*}\) & Nb & 0.0933 & 0.1119 & 0.6551 & 0.0888 & 0.7199 \({}^{*}\) \\ Mo & 0.5238 & 0.2488 & 0.9165 \({}^{*}\) & 0.4235 & 0.8317 \({}  
at the freezing front propagation [58; 59].