Two serial waterway tests, one with aeration and one without aeration, were conducted using three water tanks containing zeolite rocks, shell-bearing clastic rocks and woody biomass chips. The zeolite rocks in the first water tank (No.1) originated from Tan-no Town, Kitami City in Hokkaido, and the shell-bearing clastic rocks in the second water tank (No.2) were collected from Akan Town, Kushiro City in Hokkaido. The woody biomass chips in the third water tank (No.3) were produced from driftwood sourced from the Tokorogawa River and also disused building wood.
The results of these serial waterway tests with and without aeration can be summarized as follows:
(1) Both methods were well suited for the removal of PO₄-P, NH₄-N, NO₂-N, NO₃-N, T-N, BOD, COD and E. coli from river water.
(2) Average purification percentages for PO₄-P, NH₄-N and NO₂-N in tank No.1 of aeration tests were lower than those observed in non-aeration tests.
(3) Average purification percentages for NH₄-N, NO₂-N, NO₃-N and T-N in tank No.2 of aeration tests were higher than those observed in non-aeration tests.
(4) Average purification percentages for PO₄-P, NH₄-N, NO₃-N and T-N in tank No.3 of aeration tests were lower than those observed in non-aeration tests.
(5) Average purification percentages for NO₂-N, NO₃-N, T-N and COD in aeration tests were higher than those observed in non-aeration tests.
(6) Average purification percentages for PO₄-P, NH₄-N, BOD and E.coli in non-aeration tests were higher than those observed in aeration tests.

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REE-bearing accessory minerals of representative leucogranites of the ilmenite series were examined in the Naegi granite of the Sanyo Belt and Busetsu granite of the Ryoke Belt. Major REE-carriers appear to be rim of zircon, then monazite, xenotime and fluorite in the Naegi biotite granite, but monazite, zircon and xenotime in the Busetsu muscovite-biotite granite. Vein dikes cutting the Naegi granite (main phase) contain ferugsonite and zircon as major REE-carrier, then small amounts of thorite, rutile and fluorite. Thus, the dikes are enriched in HREE, which is due to LREE consumed to form monazite in the main phase. U and Th as well as HREE are enriched in rim of the zircon, which implies that these components were added to the host zircon crystals during the deuteric stage. Yamaguchilite and Naegite from pegmatite localities, which have been known traditionally as varieties of zircon, were also examined by EPMA. The Yamaguchilite contains up to 20.94 wt.% Σ REE₂O₃, 3.87 wt.% ThO₂ and 2.46 wt.% UO₂, while the Naegite reveals up to 3.31 wt.% Σ REE₂O₃, 12.63 wt.% ThO₂ and 6.19 wt.% UO₂. Formerly reported anomalous Nb and Ta contents in the Naegite fall below the detection limit in this study. It is thus proposed that these elements came from micro-inclusions of the Naegite in the previous analyses, which were done by wet-methods on the mineral separates.

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Chemical characteristics of apatites from S-type and I-type granites, and some igneous apatite deposits are reviewed. REE compositions of the apatites in granites are much dependent upon original composition of the granitic rocks, oxidation-redox state and fractionation degree of the granitic magmas. Highly phosphorous melts are necessary to concentrate in the El Laco-type magnetite deposits. Together with the conventionally known apatite deposits associated with some carbonatites and ultra-alkaline plutonic rocks, these rock-and-ore apatites need to be re-evaluated as a source for REE, including extraction technology.

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Geological and chemical characteristics of alkaline layered intrusions are reviewed in referring recent works from the southernmost Greenland. The Ilimaussaq alkaline complex, the Gardar Province, consists of agpaitic nepheline syenite, and is anticipated as deposits of uranium, zirconium, rare earth elements, etc. Importance of the eudialyte-bearing rocks is emphasized for the relatively high contents of HREE but low contents of radioactive elements.

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The Baerzhe Granites, best known to reveal the tetrad-effect on their REE patterns, are evaluated, on a resource basis. The granites can be significant source for heavy and intermediate REE in future. This mineralization can be comparable to the HREE-mineralized Thor Lake deposits in Canada and leuco-microgranite at Ghurayyah, Saudi Arabia.

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