Anaerobic treatment of wastewater with high organic content using a stirred tank reactor coupled with a membrane filtration unit.

Using a cross-flow membrane bioreactor, high anaerobic conversion rates of three different types of wastewater with varying organic content were achieved. Loading rates obtained were as follows: 20 g CODL(-1) x d(-1) for artificial wastewater, approximately 8 g CODL(-1) x d(-1) from vegetable processing industry (sauerkraut brine) and 6-8 g CODL(-1) x d(-1) for wastewater from an animal slaughterhouse. At stable conditions, COD-removal rates in all three wastewaters were higher than 90%. Methane yields from the treatment of artificial wastewater, sauerkraut brine, and animal slaughterhouse wastewater were in the range of 0.17-0.30, 0.20-0.34, and 0.12-0.32 L(n) x g(-1) COD(-1) fed, respectively. The complete retention of biomass and suspended solids is a unique feature of this treatment process, which combines a high loading capacity and at the same time, high COD removal rates even for complex wastewater containing high concentrations of particulate matter.

A comparison of Tactaid II+ and Tactaid 7 use by adults with a profound hearing impairment.

OBJECTIVE: To evaluate and compare use of the Tactaid II+ and the Tactaid 7, in terms of speech perception, by adults with a hearing impairment. DESIGN: Eight adults used one device daily for approximately 10 wk and attended seven training sessions. Performance was measured with tests of phonetic contrast perception, closed-set vowel and consonant identification, word and phoneme recognition in monosyllabic word lists, word recognition in sentences and speechtracking rate. A questionnaire was also administered. The protocol was repeated with the alternative device. RESULTS: With each device, the group discriminated most phonetic contrasts at better-than-chance levels and demonstrated somewhat enhanced visual or auditory-visual perception when measured in terms of vowel identification, monosyllabic word recognition and speechtracking rate. An increase in speechtracking rate was also demonstrated for some individuals. Subjects generally reported little subjective improvement in speech perception and production, but were satisfied with the physical attributes of each device. Five of six subjects preferred the Tactaid 7. CONCLUSIONS: The Tactaid II+ and the Tactaid 7 provided suprasegmental and segmental information, enabling the group to discriminate phonetic contrasts and improve their perception of some speech materials. No consistent advantage was found for either device, thought most subjects preferred the Tactaid 7. Alternatives likely to provide a greater benefit to communication should be considered before a Tactaid fitting.