Evaluation of Selected Sludge Disposal Methods

This research was undertaken to determine the feasibility of dewatering digested sludge using vacuum filters or centrifuges followed by land spreading as opposed to the present method of sludge hauling and disposal. The objectives of these experiments were to: 1 Determine whether the sludge from the Sioux Falls Wastewater Treatment Plant with the addition of a selected polymer could be dewatered by means of a vacuum filter. 2. Determine whether the sludge from the Sioux Falls Wastewater Treatment Plant with the addition of a selected polymer could be dewatered by means of a solid bowl centrifuge. 3. Establish capita costs for sludge dewatering and disposal by means of vacuum filtration, centrifugation and the existing method of lagoons and drying beds with land application.4. Establish operation and maintenance costs for sludge dewatering and disposal by means of vacuum filtration, centrifugation and the existing method of lagoons and drying beds with land application. 5. Compare the average annual costs of the three mentioned dewatering and disposal methods

Analysis of nocturnal actigraphic sleep measures in patients with COPD and their association with daytime physical activity

Background: Sleep disturbances are common in patients with chronic obstructive pulmonary disease (COPD) with a considerable negative impact on their quality of life. However, factors associated with measures of sleep in daily life have not been investigated before nor has the association between sleep and the ability to engage in physical activity on a day-to-day basis been studied. Aims: To provide insight into the relationship between actigraphic sleep measures and disease severity, exertional dyspnoea, gender and parts of the week; and to investigate the association between sleep measures and next day physical activity. Methods: Data were analysed from 932 patients with COPD (66% male, 66.4±8.3 years, FEV1% predicted=50.8±20.5). Participants had sleep and physical activity continuously monitored using a multisensor activity monitor for a median of 6 days. Linear mixed effects models were applied to investigate the factors associated with sleep impairment and the association between nocturnal sleep and patients' subsequent daytime physical activity. Results: Actigraphic estimates of sleep impairment were greater in patients with worse airflow limitation and worse exertional dyspnoea. Patients with better sleep measures (ie, non-fragmented sleep, sleeping bouts ≥225 min, sleep efficiency ≥91% and time spent awake after sleep onset < 57 min) spent significantly more time in light (p < 0.01) and moderate-to-vigorous physical activity (p < 0.01). Conclusions: There is a relationship between measures of sleep in patients with COPD and the amount of activity they undertake during the waking day. Identifying groups with specific sleep characteristics may be useful information when designing physical activity-enhancing interventions