No abstract

A SHARON® system has been constructed at the Utrecht WWTP and at the Rotterdam Dokhaven WWTP. In the SHARON® process rejection water from dewatering of digested sludge is treated for N-removal. It concerns a high active process operating without sludge retention. Due to differences in growth rate nitrite oxidisers can be washed out of the system while ammonia oxidisers are maintained, resulting in N-removal over nitrite. The SHARON® process was selected in competition with several other techniques. The feed of a SHARON® system is concentrated, with ammonia concentrations ranging from 0.5 to 1.5 g N/l. The results show that conversion rates of 90% are well possible with N-removal mainly via the nitrite route. The process was shown to be stable. Due to the high ammonium influent concentrations pH control is of great importance, preventing process inhibitions. The acidifying effect of nitrification can be compensated completely by CO2 stripping during aeration and by denitrification. Heat production by biological conversions is significant, due to the high inlet concentrations, and contributes to the optimal operating temperature of 30-40°C.

At the Rotterdam Dokhaven WWTP the first full-scale application of the SHARON process has been constructed. In the SHARON process, rejection water from dewatering of digested sludge is treated for N-removal. It concerns a highly active process operating without sludge retention. The single tank reactor is intermittently aerated. Due to differences in growth rate nitrite oxidisers are washed out of the system while ammonia oxidisers can be maintained, resulting in N-removal over nitrite. The SHARON process has been selected after comparison with several other techniques. The feed of the SHARON tank is concentrated, with ammonia concentrations over 1 g N/l. The first results show that conversion rates of 90% are quite possible with N-removal mainly via the nitrite route. The process was shown to be stable. Due to the high inlet concentrations pH control is of great importance, preventing process inhibitions. The acidifying effect of nitrification can be compensated completely by CO2 stripping during aeration and by denitrification. Heat production by biological conversions appeared to be significant, due to the high inlet concentrations, and contributes to the optimal operating temperature of 30-40 degrees C.

The knowledge of being infected with the human immunodeficiency virus type 1 (HIV-1) brings about psychological distress and social problems including anxiety, depression, and social isolation. Participating in psychosocial intervention programs can help to reduce these problems. To date, however, very little is known about the efficacy of different intervention strategies. We implemented a study with a randomized experimental design to investigate the effectiveness of a cognitive-behavioral group psychotherapy (CBT) and an experiential group psychotherapy (ET) program for 39 asymptomatic HIV-infected homosexual men. Both therapies consisted of 17 sessions over a 15-week period. The major finding of this study was that psychosocial intervention, independent of the therapeutic orientation, decreased distress significantly, as compared with a waiting-list control group (WCG). There were no significant changes in the intervention groups as compared with the WCG in coping styles, social support, and emotional expression. Finally, CBT and ET did not differ in their effects on psychological distress or on the other psychosocial variables measured in this study.

Aims/hypothesis. Our study investigated the prognosis of Type 2 diabetic patients with silent myocardial infarction in a community-based cohort. Methods. We analysed data from 1269 patients with Type 2 diabetes mellitus from a community-based observational study of diabetes care, control and complications. Silent myocardial infarction was defined as Q waves (Minnesota codes 1.1, 1.2) on a baseline electrocardiogram in the absence of a history or symptoms of CHD. Results. Silent myocardial infarction was present in 3.9% of patients, or 44% of all Q-wave myocardial infarctions. The patients were subdivided into those with (i) no clinical or Q-wave evidence of myocardial infarction (Group 1), (ii) silent myocardial infarction (Group 2), (iii) self-reported CHD but no Q waves (Group 3), and (iv) self-reported CHD and Q waves (Group 4). Compared to Groups 3 and 4, Group 2 patients were more likely to be women, less likely to have smoked, and had higher serum HDL-cholesterol concentrations and higher blood pressure. Over an average of seven years, and after adjusting for other independent predictors of death, all-cause and CHD mortality were similar in Groups 1 and 2 and greater (twofold for all-cause and fourfold for CHD mortality) in Groups 3 and 4. Conclusions/interpretation. Silent myocardial infarction is common in Type 2 diabetes and has a prognosis similar to that in patients without a history of CHD or Q waves. [Diabetologia (2004) 47:395-399]