Ceramsite Facilitated Microbial Degradation of Pollutants in Domestic Wastewater

Although constructed wetlands (CWs) are widely used around the world with various substrates, the mechanisms of how these modified substrates affect wastewater treatment are still unknown. In this study, CW microcosms were established with and without ceramsite as a substrate, and the wastewater treatment efficiencies were evaluated during 71 days of incubation. Using the 16S rRNA high-through sequencing, the mechanisms of how CW substrate changed the microbial community was quantified. The results showed that compared to soil as substrate, the use of ceramsite as substrate material enhanced the removal of pollutants from CW systems, particularly under a short retention time (1.5-day) condition. There were more beneficial microorganism groups (nitrogen, sulfur, phosphate) in the ceramsite CW system than the non-ceramsite CW system, particularly in the bottom layers. Moreover, the CW with ceramsite substrate had more nitrification function. All of these results suggested that the ceramsite CW system enhanced the removal of pollutants because it increased the concentration of key microbes that are necessarily for nutrient cycles.

Fate of selected pharmaceuticals and their metabolites in soil aquifer treatment

Through a series of long-term column experiments, the fate of three common pharmaceuticals (carbamazepine (CBZ), diclofenac, and indomethacin) and their major phase I metabolites in soil aquifer treatment (SAT) were monitored. CBZ concentration increased by a factor of two (from 37 to ca. 70 ng/L) regardless of the treatment conditions, and its metabolites, 10,11-dihydro-10-hydroxycarbamazepine (approximately 500 ng/L after SAT) and CBZ-10,11-epoxide (12–42 ng/L after SAT) were not effectively removed after SAT. Our results indicated that some metabolites of pharmaceuticals are present at much higher concentration than the original forms in the SAT effluent, and that some metabolites are more persistent during SAT with a relatively short retention time (i.e., 30 days). The study indicated that more attention should be paid to the formation and fate of metabolites in the water quality management of SAT effluent.

A novel porphyrin-containing polyimide for memory devices

A novel porphyrin-based polyimide ZnPor-t-DSDA was synthesized for memory applications and exhibits symmetric biswitching characteristic with a short retention time due to the coplanar structure between donor and acceptor units.

Prevention of bromate formation by adsorption phase ozonation using high silica zeolites

The objectives of this work are to propose a novel ozonation process in adsorption phase using high silica zeolites and elucidate its advantages for simultaneous achievement of prevention of bromate formation and sufficiently high ozonation performance. Bromate is formed from bromide during ozonation under conventional conditions and needs to be reduced at least below a regulated concentration because of its considerable carcinogenicity. The ozonation of 2-methylisoborneol (2-MIB), a model Taste and Odor (T&O) chemical, has been studied in our process. It was known that 2-MIB is adsorbed onto high silica zeolite and oxidized with ozone rapidly in micropores. An adsorbent, named US-Y, in which the SiO2/Al2O3 ratio is 70, was the best candidate in this study in terms of adsorption of 2-MIB, decomposition of 2-MIB and prevention of bromate formation. Actually, bromate formation was not detected, while about seventy five percent of 2-MIB was decomposed with extremely low ozone concentration of 0.07 ppm and short retention time of 0.2 min in the presence of US-Y. Its applicability for the treatment of natural water containing natural organic matters (NOMs) was also demonstrated.

Studies on the Contact Biofilter as a Compact Process in Domestic Sewage Treatment

This paper describes the treatment performance of a newly developed compact treatment process, named the “contact biofilter”. It is composed of a submerged biofilter and a granular medium filter. The research experiments on the process were conducted using domestic sewage. It was clearly shown that this process could reduce SS and total BOD in effluent to below 10 and 20 mg/l, respectively, in a short retention time, and it can be used as a secondary treatment process. The organic substances in sewage are effectively recovered as sludge without extensive mineralization.