Treatment of mixed municipal and winery wastewaters in a conventional activated sludge process: a case study.

The possibility of co-treating municipal and winery wastewaters in a conventional activated sludge process was studied at full scale. The wastewater treatment plant considered in this paper operated an extended-oxidation process during vintage (four month per year) and a pre-denitrification/ oxidation process during the rest of the year. The experimentation showed that good performances, in terms of COD and nitrogen removal, could be obtained in both cases: 90% and 60%, for COD and nitrogen removal, respectively. Thanks to the high solid retention times applied to the system (up to 48 days) the waste activated sludge production was low (0.20 kgMLVSS/kgCODremoved) and respiration was the main process for carbon removal. Nitrification was always satisfactory while the behaviour of the denitrification process during vintage was not totally understood and further studies are going on.

Regulation of intraocular pressure after water drinking.

PURPOSE: Acute oral water loading transiently elevates intraocular pressure (IOP) via mechanisms that remain unexplained. We tested the possibilities that water drinking might elevate IOP by creating a blood-aqueous osmotic gradient, or that it might instead alter active ion pumping and the formation of aqueous humor. METHODS: In the first series, 16 young, healthy individuals were studied during dehydration and for 1 hour after rehydration (14 mL H2O/kg body weight). Hematocrit, total plasma osmolality, and plasma colloid osmotic pressure were determined simultaneously with measurements of IOP. In a second series (N = 16), rehydration occurred after pretreatment with either placebo or a topical carbonic anhydrase inhibitor (1 drop 2% dorzolamide in each eye, 12 and 2 hours before oral water loading). RESULTS: In both series, mean IOP increased significantly 15 minutes after water ingestion and remained elevated above baseline for 45 minutes. In contrast, colloid osmotic pressure and hematocrit were unaltered by water drinking, and neither these variables nor total plasma osmolality correlated with IOP. In the second series, pretreatment with dorzolamide reduced baseline IOP, but failed to alter the magnitude or time course of IOP elevations induced by water drinking. CONCLUSION: Because water drinking failed to create a blood-ocular osmotic pressure gradient, neither vitreous hydration nor increased aqueous ultrafiltration can explain increases in IOP after acute hydration. Because the increase in ocular tension apparently also is independent of active bicarbonate pumping, factors affecting aqueous drainage must explain the water drinking effect.