Comparing environmental impacts of tertiary wastewater treatment technologies for advanced phosphorus removal and disinfection with life cycle assessment.

Different technologies for tertiary wastewater treatment are compared in their environmental impacts with life cycle assessment (LCA). Targeting very low phosphorus concentration (50-120 µg/L) and seasonal disinfection of wastewater treatment plant (WWTP) secondary effluent, this LCA compares high-rate sedimentation, microsieve, dual media filtration (all with UV disinfection), and polymer ultrafiltration or ceramic microfiltration membranes for upgrading the large WWTP Berlin-Ruhleben. Results of the LCA show that mean effluent quality of membranes is highest, but at the cost of high electricity and chemical demand and associated emissions of greenhouse gases or other air pollutants. In contrast, gravity-driven treatment processes require less electricity and chemicals, but can reach significant removal of phosphorus. In fact, dual media filter or microsieve cause substantially lower specific CO2 emissions per kg P removed from the secondary effluent (180 kg CO2-eq/kg P, including UV) than the membrane schemes (275 kg CO2-eq/kg P).

Gastric dysrhythmias and delayed gastric emptying in patients with functional dyspepsia.

An association between dyspepsia, gastric motility disorders, and myoelectrical abnormalities has been noted. The objective of the present study was to investigate both antral myoelectrical activity and gastric emptying in patients with functional dyspepsia (FD). Electrogastrography (EGG) was performed in 25 adult patients with FD, which had been evaluated by score. After an overnight fast, for 1 hr in the pre- and postprandial state (370 kcal liquid-solid test meal) the following EGG parameters were determined: dominant frequency [DF (cpm)], DF (%) in the normal range (2-4 cpm), bradygastria (<2 cpm), tachygastria (4-10 cpm), dominant frequency instability coefficient (DFIC), and postprandial to fasting power ratio (PR). The data were correlated to results obtained in 20 age- and gender-matched controls. In addition, in 17 consecutive patients the EGG data were compared to the gastric retention of radionuclides after 60 min (liquid-solid phase labeled with 99mTc colloid). Patients with FD revealed a preprandial increase in tachygastria compared to controls (P < 0.001). Of 17 FD, seven patients exhibited delayed gastric emptying (t60 retention >68%). These patients showed significantly more pre- and postprandial tachygastrias than patients with normal gastric emptying (P < 0.05). The dyspeptic symptomatology and H. pylori status did not correlate with EGG and radioscintigraphy. Patients with FD frequently reveal impaired gastric emptying and increased tachygastria, which may have pathophysiological significance in some of these patients.