Greywater Treatment by High Rate Algal Pond under Sahelian Conditions for Reuse in Irrigation

High Rate Algal Pond (HRAP) was constructed and operated using a mixer device to investigate its capability in treating greywater for reuse in gardening. Physico-chemical and microbiological parameters were monitored. With a hydraulic retention time of 7.5 days and a solid retention time of 20 days, the average removal efficiencies (ARE) were 69% and 62% for BOD5 and COD respectively. The ARE for , and were 23%, 52% and 43% respectively. The removal of suspended solids (SS) was unsatisfactory, which could be attributed to the low average algal settling efficiencies of 9.3% and 16.0% achieved after 30 and 60 minutes respectively. The ARE of fecal coliforms, Escherichia coli and enterococci were 2.65, 3.14 and 3.17 log units respectively. In view of the results, the HRAP technology could be adapted for greywater treatment in sahelian regions. However, further studies on the diversity of the algal species growing in the HRAP unit are necessary in order to increase the removal of SS. Hazards of a reuse of the effluents are discussed on the basis of the various qualitative parameters. The residual content of E. coli was varying from 4 CFU per 100 mL. Based on WHO guidelines for greywater reuse in irrigation, the effluents could be used for restricted irrigation (E. coli < 105 CFU per 100 mL). Furthermore, the reuse potential is discussed on the basis of FAO guidelines using SAR (3.03 to 4.11), electrical conductivity (482 to 4500 μS/cm) and pH values (6.45 to 8.6).

Cochlear Implantation in Patients with Eosinophilic Otitis Media

It is known that cochlear implantation for deaf patients with eosinophilic otitis media (EOM) is safe and can provide good speech perception. However, the best timing of implant surgery in patients with EOM is not yet known. The aim of this case report is to suggest the appropriate timing of the surgery in EOM patients with deaf. Cochlear implantation was indicated in two patients with EOM. One underwent cochlear implantation in the absence of any ear discharge. In the other case, implant surgery was delayed for three years due to persistent ear discharge. No complications related to implant device or skin flap were observed in either case. The speech recognition score after implantation was good in the first case and poor in the second case. Perioperative complications were manageable even in the patient with persistent ear discharge. However, the delay in implant surgery due to the persistent ear discharge resulted in a poor speech recognition score. Early implantation should be considered even in EOM patients with ear discharge, although the presence of active middle ear inflammation is regarded as one of the contraindications for implantation according to the current Japanese guidelines.

A Postimplant Cholesteatoma after Modified Radical Mastoidectomy

A postimplant cholesteatoma is one of surgical complications of cochlear implantation. Hoffman and Cohen (1995) reported that only one out of 172 (0.58%) patients developed a postimplant cholesteatoma. We experienced a case of postimplant cholesteatoma after the modified radical mastoidectomy. Case: A 61-year-old man underwent left modified radical tympanoplasty with mastoidectomy for middle ear cholesteatoma at another hospital 40 years ago. We performed right open type tympanoplasty for right cholesteatoma, and at that time there was no recurrent cholesteatoma on the left side. He had already lost the sensorineural hearing in both ears. After three-year-observation with no recurrence of cholesteatoma in both ears, the patient underwent a left cochlear implantation with a Nucleus-24 channel device. After 1 year, we found new lesion of cholesteatoma in the left attic, and removed it by transcanal approach. There has been no recurrence of cholesteatoma for 12 years. Conclusion: In long-standing middle ear problems, when we perform cochlear implantation, even though there is good aeration of the middle ear and an intact tympanic membrane, we need to adequately reflect on the area which should be obliterated.

Catalyst-free growth of ZnO nanowires on various-oriented sapphire substrates by pulsed-laser deposition

Catalyst-free growth of one-dimensional zinc oxide （ZnO） nanowires is reported. ZnO nanowires were synthesized on ZnO buffer layers deposited on various-oriented sapphire substrates. Syntheses of ZnO buffer layers and nanowires were performed by ultraviolet pulsed-laser deposition. ZnO nanowire＇s number density was the lowest in the case of using m-cut sapphire substrates. ZnO nanowires grown on a-cut sapphire substrates had vertical alignment with distances of tens to hundreds of nanometers. On the other hand, ZnO nanowires grown on c-cut sapphire substrates had the biggest nucleation rate. The dependence of crystalline orientation of ZnO buffer layers on the orientation of sapphire substrates were investigated by electron back scatter diffraction measurement. From their results, the growth models of ZnO buffer layers were suggested and the variations in morphological properties ofZnO nanowires were discussed.