Technical and economic analysis of real anaerobic digester centrate by means of partial nitrification and sustainable heterotrophic denitrification.

The reliability of partial nitrification coupled with heterotrophic denitrification for the treatment of real anaerobic digester centrate produced in a wastewater treatment plant was technically and economically assessed in two sequencing batch reactors. Removal efficiencies above 90% were consistently achieved at N-ammonium loads above 1.2 g N L⁻¹ d⁻¹. Ethanol, affluent from a waste water treatment plant (biological treatment inlet) and a zero-cost liquid residue from a chemical industry containing polyethylene glycol and sorbitol were employed as carbon source for denitrification. In this last case, a total organic carbon (TOC) requirement of 4.5 g TOC g⁻¹ NO2⁻-N was calculated. The denitrification rate was 0.26 g NO2⁻-N g VSS⁻¹ d⁻¹ (VSS: volatile suspended solids). These results show that a carbon-rich waste can serve as a no-cost feed for denitrifying bioreactors. An in-depth economic analysis considering the main investment and operating costs of the process was developed, showing that it can suppose yearly savings above 50% with respect to the most widely used alternative of returning anaerobic digester centrate untreated to the head of the facility.

Emergency perception and other variables associated with extra-hospital delay in stroke patients in the Maresme region (Spain).

Delay in arrival to the emergency room (ER) may negatively influence outcome of stroke patients. We aim to analyze factors that influence extra-hospital delay in stroke patients. Two hundred and ninety-two consecutive stroke patients admitted in the ER were prospectively studied. Analysis was made to identify variables associated with <1- and <3 h delays from onset. About 18.8% of patients arrived before 1 h and 57.5% before 3 h. Factors independently associated with <3 h delay were decision to go immediately to ER (OR = 8.17; 95% IC = 4.47-18.8), ambulance transportation (OR = 2.35; 1.36-4.05) and total anterior circulation syndrome (TACS) (OR = 3.74; 1.51-9.24). History of >1 vascular risk factor was associated with a greater delay (OR = 0.47; 0.26-0.86). Factors associated with a <1 h delay were: (i) immediate decision to attend the ER (OR = 3.55; 1.85-6.81), (ii) stroke on Sunday (OR = 3.46; 1.56-7.66), (iii) aphasia (OR = 2.41; 1.23-4.74), (iv) absence of stairs at home (OR = 0.37; 0.17-0.81) and (v) absence of diabetes mellitus (OR = 0.42; 0.20-0.88). In our area, nearly 60% of stroke patients arrive to ER before 3 h from onset. Immediate decision to attend the ER has the strongest association with a short delay. Patients with TACS arrived mainly before 3 h and those with isolated aphasia arrived before 1 h. Patients with vascular risk factors attended the hospital later. Ambulance transportation is associated with <3 h delay, but not with <1 h.

Esterilización endoscópica / Endoscopic sterilization

Se informa la introducción en Cuba del método endoscópico para la esterilización tubaria con una serie de 200 casos, utilizando una medificación de la técnica extranjera que sustituye la electrocoagulación por la termocauterización. Se discute la conveniencia de realizar dos cortes a cada trompa y se muestra la ausencia de morbilidad o mortalidad por este procedimiento (AU)