Application of a generalized hybrid machine learning model for the prediction of H2S and VOCs removal in a compact trickle bed bioreactor (CTBB).

This study presents a generalized hybrid model for predicting H2S and VOCs removal efficiency using a machine learning model: K-NN (K - nearest neighbors) and RF (random forest). The approach adopted in this study enabled the (i) identification of odor removal efficiency (K) using a classification model, and (ii) prediction of K <100%, based on inlet concentration, time of day, pH and retention time. Global sensitivity analysis (GSA) was used to test the relationships between the inputs and outputs of the K-NN model. The results from classification model simulation showed high goodness of fit for the classification models to predict the removal of H2S and VOCs (SPEC = 0.94-0.99, SENS = 0.96-0.99). It was shown that the hybrid K-NN model applied for the "Klimzowiec" WWTP, including the pilot plant, can also be applied to the "Urbanowice" WWTP. The hybrid machine learning model enables the development of a universal system for monitoring the removal of H2S and VOCs from WWTP facilities.

Odor and volatile organic compounds biotreatment using compact trickle bed bioreactors (CTBB) in a wastewater treatment plant.

The main aim of this study was to optimize and maximize the impacts of odor and volatile organic compounds (VOCs) biodegradation in a wastewater treatment plant utilizing a pilot-scale compact trickle bed bioreactor (CTBB). A CTBB was built and tested for its long-term performance during which gases were supplied from the tank containing semi-liquid fats, oils, and fat waste. The concentrations of pollutants ranged from 0 to 140.75 mg/m3 H2S, 0 to 2500 mg/m3 VOCs, and 0 to 21.5 mg/m3 NH3. The CTBB was tested at different gas flow rates and at two pH values for the liquid phase: pH = 7.0 and 5.0. In the liquid phase, the pollutant removal efficiency was higher at pH = 7.0 than at pH = 5.0. Overall, the removal efficiency was between 81.5 % and 99.5 % for the VOCs and 87.5 % and 98.9 % for H2S, while NH3 removals were >99 %.

[Sport habits and sedentary lifestyle among elementary school children in Obuda, Hungary]. / Sportolási szokások és inaktív életmód óbudai általános iskolások körében.

UNLABELLED: Childhood obesity has become a worldwide epidemic. Declining physical activity is one of the major contributors. AIM: To obtain data on Hungarian primary school students' weight status, sport club participation and sedentary behaviors. METHODS: A cross-sectional survey was distributed to all primary schools (n=18) in Obuda, Budapest. Children (1648 boys, 1654 girls; 11.3+/-2.3 years) completed questionnaires about sedentary behaviors and sport participation. Height, weight and waist circumference were measured. RESULTS: According to the IOTF criteria, 14.5% of the children were overweight and 4.6% were obese. The rate of those children who did not attend any extracurricular sport increased parallel with age in both gender. At the lower end of the range, 15.3% of the 9-year-old boys and 21% of the 10-year old girls did not sport. These numbers increased up to 31.0% in boys and 53.8% in girls by the age of 15 years. Screening time on weekdays and on weekends was 2.2+/-1.9 and 3.6+/-2.6 hours/day, respectively. One third of participants (32.2%) spent >2 h/day in front of a screen on weekdays, whereas 61.8% did on weekends. CONCLUSIONS: The frequency of sedentary behaviors was high among urban Hungarian school children. Health promotion strategies should start in early ages.

Role of waist circumference in predicting the risk of high blood pressure in children.

OBJECTIVE: This paper was designed to evaluate the role of waist circumference (WC) in identification of children with high blood pressure. METHODS: Cross-sectional data on body mass index (BMI), WC and blood pressure (BP) were analyzed in 3 678 children (1 849 boys; 11.3 +/- 2.3 years) who participated in the LEARN study. RESULTS: Prevalence of abdominal obesity (WC >or=90th percentile) in normal weight (n = 2 982), overweight (n = 528) and obese (n = 168) children were 3.7%, 51.7% and 89.9%, respectively. Systolic BP (SBP) was higher in children with abdominal obesity compared with those with normal WC (p < 0.01) both in normal and in overweight BMI categories. Similar results were found for diastolic BP (DBP) in normal weight girls (p = 0.032) and overweight boys (p = 0.04). WC was significantly correlated with SBP and DPB in all BMI categories, even after adjustment for age and BMI. Despite these findings, no significant odds ratio (OR) of prehypertension or hypertension for abdominal obesity was found in the normal weight category. On the contrary, in overweight children, prevalence of prehypertension (OR 1.42 [1.1; 1.8]) and hypertension (OR 1.35 [1.1; 1.7]) was higher among abdominal obese children. Similarly, the prevalence of prehypertension was almost two-times higher among obese children with abdominal obesity (11.8% vs. 22.5%); however, no significant OR was found. CONCLUSIONS: The ability of WC to detect high-risk normal weight children is controversial. The additional measure of WC among overweight children seems to be relevant in identifying those at increased risk of high BP. Further research with a larger sample size is required in the obese group.

The effects of 6-week low glycemic load diet based on low glycemic index foods in overweight/obese children--pilot study.

OBJECTIVE: To evaluate the effectiveness of a 6-week low Glycemic Load (GL) diet intervention based on low Glycemic Index (GI) foods on body weight, body composition, metabolic risk factors and satiety in overweight/obese pre-pubertal children. METHODS: Following a pediatric examination 8 healthy, average age 11 year old, Caucasian, pre-pubertal overweight/obese (BMI = 24, 7 +/- 3.8 kg/m(2)) children participated in the study. The Low GL diet intervention was based on the replacement of at least 50% of the high GI foods with Low-GI foods. The children with one of their parents participated in weekly nutrition consultations. Body composition, fasting glucose, insulin, cholesterol and triglyceride were measured before and after the study. Dietary changes were made based on weekly 4-day food-diaries. RESULTS: Despite no change in body weight, there was a significant (p < 0.05) reduction in % body fat (29.4 +/- 4.2 vs. 25.4 +/- 5.3), Waist-to-Hip Ratio (WHR 0.87 +/- 0.053 vs. 0.86 +/- 0.05), decrease in self-reported hunger level (4.37 +/- 0.74 vs. 1.75 +/- 0.75) and the total number of risk factors (28 vs. 15). There was a strong negative correlation between fasting glucose and insulin levels at baseline and in the magnitude of change after the study (r = -0.93 and r = -0.85 respectively; p < 0.01). CONCLUSIONS: A 6 week study demonstrated the practicality and effectiveness of this Low GL dietary approach. Despite of the unchanged body weight, Low GL diet consultations positively modified body fat content and cardiovascular risk factors in overweight or obese children.