Performance evaluation and kinetic modeling of an upflow anaerobic sludge blanket septic tank for domestic wastewater treatment.

This work evaluated the UASB-septic tank performance using different kinetic models that correlated process efficiency and methane production with hydraulic and organic loading rates through experiments with five different HRT (48 h, 36 h, 24 h, 18 h, and 12 h) using synthetic domestic wastewater. The modified Stover-Kincannon model provided the best fitting to calculate kinetics constants, with an R above 98% for linear regression, and predicted the effluent COD more accurately than the other models. Methane yield was 0.

Toxic atmospheric pollutants from crematoria ovens: characterization, emission factors, and modeling.

Human remains and corpses' cremation is an increasing practice worldwide alternative to burials, which have increased their cost and reduced spaces in cemeteries. Alike to other combustion processes, cremation produces pollutant emissions that contribute to worsen air quality in modern cities. A 6-month sampling campaign was performed in order to characterize emissions from corpse cremation in three different crematorium ovens and develop emission factors which were used to determine the population exposure to those pollutants during cremation activities applying a dispersion model.

Effect of platform subway depth on the presence of Airborne PM, metals, and toxic organic species.

PM that have been related to public health risks, were collected during two seasons with High-Vol samplers in platforms of a Mexican subway station, which interconnects through transfers three lines having different depths. The objective was to study the influence of depth on the PM concentrations and their species. PM concentrations in cold-dry and warm-dry seasons presented statistical differences, being in average 57 and 66 μgm respectively, in the shallower line 9; 90 μgm and 111 μgm in line 1; and 104 and 122 μgmin the deepest line 7.

Emission factors of atmospheric and climatic pollutants from crop residues burning.

Unlabelled: Biomass burning is a common agricultural practice, because it allows elimination of postharvesting residues; nevertheless, it involves an inefficient combustion process that generates atmospheric pollutants emission, which has implications on health and climate change. This work focuses on the estimation of emission factors (EFs) of PM, PM, organic carbon (OC), elemental carbon (EC), carbon monoxide (CO), carbon dioxide (CO), and methane (CH) of residues from burning alfalfa, barley, beans, cotton, maize, rice, sorghum, and wheat in Mexico. Chemical characteristics of the residues were determined to establish their relationship with EFs, as well as with the modified combustion efficiency (MCE).

Emission factors from different burning stages of agriculture wastes in Mexico.

Open-air burning of agricultural wastes from crops like corn, rice, sorghum, sugar cane, and wheat is common practice in Mexico, which in spite limiting regulations, is the method to eliminate such wastes, to clear the land for further harvesting, to control grasses, weeds, insects, and pests, and to facilitate nutrient absorption. However, this practice generates air pollution and contributes to the greenhouse effect. Burning of straws derived from the said crops was emulated in a controlled combustion chamber, hence determining emission factors for particles, black carbon, carbon dioxide, carbon monoxide, and nitric oxide throughout the process, which comprised three apparent stages: pre-ignition, flaming, and smoldering.