A novel method for removing nitrate in waste water which uses wood chips as a reduction agent and growth support mechanism for denitrification bacteria is studied in this report. A higher denitrification rate was obtained when a portion of the wood chips packed in a column were exposed to air than when all of the wood chips were entirely immersed in solution. Cherry tree chips were more effective than cedar chips, as almost a 100% denitirification rate was maintained for at least 69 days at an inlet concentration of 20mg-N/L and HRT of 20 hr. The denitrification rate decreased significantly when the initial nitrate concentration was increased from 21mg-N/L to 46 mg-N/L. It was possible to use wood chips exclusively as a supply source of organic compounds. An excess amount of organic compounds which is discharged from the reactor can be reduced by passing the solution through a column packed with activated carbon. Cedar chips prepared from a fresh log shortly after cutting were used as a supporting material for denitirification bacteria. A satisfactorily high degree of denitirifation was obtained at HRT of 0.76 hr by adding ethanol as a reduction agent for nitrate.

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Waste poly (vinyl chloride: PVC) resins are experimentally dehydrochlorinated by microwave irradiation. The following unique results are obtained: (1) plasticizer in PVC resin absorbs microwave power more effectively than PVC polymer. The higher the plasticizer content in PVC resin, the higher is the dehydrochlorination reaction (2) low PVC polymer content materials such as cushion floor require high microwave irradiation power to secure a high dehydrochlorination yield, (3) calcium carbonate in PVC resin reacts with released hydrochloric acid gas and results calcium chloride during microwave irradiation, (4) additives in PVC resin strongly influence dehydrochlorination yield, (5) it is evidenced that the PVC copolymer is also dehydrochlorinated by microwave irradiation.

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A series of sorbents with mean diameters no greater than φ75μm was prepared by a crosslinking reaction with β-cyclodextrin (βCyD) and diisocyanates followed by ball-milling. The sorbent synthesized with hexamethylene diisocyanate (HDI) as a crosslinker showed better phenol removal efficiency than that with toluene 2,6-diisocyanate (TDI). The greatest removal efficiency was achieved with βCyD/HDI (1/8) sorbent which was obtained by the crosslinking of βCyD with HDI in a 1 : 8 molar ratio. The removal of the phenolic compounds from the raw industrial wastewater was almost instantaneous and the sorbents were efficiently regenerated by the elution of the adsorbed phenols with methanol. The βCyD/HDI (1/8) sorbent effectively removed phenol from phenolic wastewater containing 89 g/L phenol to concentrations as low as 117 mg/L, using five times accumulated batchwise treatments. Adsorption by the use of a liquid-solid fluidized bed was also carried out.

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