Go or no go for gel entrapped nitrifiers? A Belgian case study.

In the coming years, as stricter environmental requirements are imposed, many European Union wastewater treatment plants (WWTP) need to be expanded and/or upgraded. This requires considerable investments. Optimising the renovation recourses can lead to significant savings. The use of entrapped nitrifying bacteria for upgrading of WWTP towards nutrient removal may be benificial. Long term pilot tests were performed to evaluate a so-called pellet reactor. Differences in performance and microbiological composition of classical activated sludge and the pellet reactor were investigated. FISH analyses showed (i) absence of Nitrobacter cells and (ii) high abundance of Nitrospira in the pilot reactors. Two Belgian WWTP make use of fine bubble aeration and could--theoretically--easily be renovated towards nitrogen removal using encapsulated nitrifiers. Financial aspects are commented on.

Combined ozone-activated sludge treatment of landfill leachate.

Biological treatment is widely preferred by many landfill owners to remove the bulk of the pollutants in leachate. Specific problems due to toxicity and nutrient deficiencies are however frequently reported. This study investigates the possibility of pre-treating leachate to decrease its toxicity and increase its biodegradability, using ozonation. Lab-scale and pilot testing has shown that nitrification toxicity was minimised by ozone pre-treatment. A decrease of the COD/BOD-ratio from 16 to 6 was achieved, making the pre-treated leachate co-treatable in municipal sewage treatment. The operational cost for the pre-treatment was estimated at 1.34 Euro/kg COD.

HACCP (Hazard Analysis and Critical Control Points) to guarantee safe water reuse and drinking water production--a case study.

To obtain a sustainable water catchment in the dune area of the Flemish west coast, the integration of treated domestic wastewater in the existing potable water production process is planned. The hygienic hazards associated with the introduction of treated domestic wastewater into the water cycle are well recognised. Therefore, the concept of HACCP (Hazard Analysis and Critical Control Points) was used to guarantee hygienically safe drinking water production. Taking into account the literature data on the removal efficiencies of the proposed advanced treatment steps with regard to enteric viruses and protozoa and after setting high quality limits based on the recent progress in quantitative risk assessment, the critical control points (CCPs) and points of attention (POAs) were identified. Based on the HACCP analysis a specific monitoring strategy was developed which focused on the control of these CCPs and POAs.

Motor activity and severity of depression in hospitalized prepubertal children.

OBJECTIVE: To determine whether there is an association between activity levels and the severity and nature of depressive symptoms. METHOD: Locomotor activity was quantified in 27 consecutively selected hospitalized prepubertal children. Activity was measured in 5-minute epochs over a period of 72 hours using belt-worn monitors. Depressive symptoms were rated using the Children's Depression Rating Scale-Revised, the Children's Depression Inventory, and an observer rating scale for nursing staff. RESULTS: Measures of reduced daytime activity correlated with scores on the Children's Depression Rating Scale and the observer rating scale, but not the Children's Depression Inventory. Stepwise regression indicated that the strongest association occurred between a composite measure of severity, age, and percentage of low-level diurnal activity periods (r = .724, p < .0005). Activity measures correlated with clinical ratings of sadness, low self-esteem, anhedonia, and physical complaints, and to a lesser degree with ratings of hypoactivity, fatigue, and slow speech. CONCLUSIONS: Reduced levels of activity correlated significantly with clinical ratings of depressive severity across diagnostic groups. The development of objective measures of depressive severity may have prognostic and therapeutic implications.

Shifts in diagnostic frequencies of schizophrenia and major affective disorders at six North American psychiatric hospitals, 1972-1988.

OBJECTIVE: This study tested the impression that there have been significant shifts in the relative diagnostic frequencies of schizophrenia and major affective disorders. METHOD: Data on discharge diagnoses from 1972 to 1988 were gathered from six North American psychiatric teaching hospitals (data from one extended through 1991), and rates for schizophrenia and major mood disorders were evaluated. RESULTS: Total annual discharges increased by 6.6% during the study period. Large reciprocal shifts in the frequencies of diagnoses of schizophrenia and major affective disorders were found; schizoaffective disorder was a minor diagnosis. Beginning in the early 1970s, a gradual increase in the frequency of diagnoses of major affective disorders at all sites was accompanied by a corresponding decrease in diagnoses of schizophrenia at five of the six centers. Schizophrenia diagnoses decreased from a peak of 27% in 1976 to 9% in 1989 (a threefold decrease), and diagnoses of major affective disorders rose from a low of 10% in 1972 to 44% in 1990 (a fourfold increase). CONCLUSIONS: Several forces may have influenced these changes. 1) DSM-III narrowed the definition of schizophrenia and broadened the category of major affective disorders. 2) Treatment-oriented diagnostic bias associated with the availability of lithium and other mood-altering agents may have encouraged consideration of affective disorders. 3) Economic and social forces, including better third-party reimbursement rates, may have favored affective diagnoses. 4) True increases in the incidence of affective disorders may have occurred. 5) Although a real decrease in new cases of schizophrenia may have occurred, this effect was probably minor and dominated by a larger shift of such diagnoses to affective categories.