Application of catalytic ozonation using Y zeolite in the elimination of pharmaceuticals in effluents from municipal wastewater treatment plants.

Catalytic ozonation using faujasite-type Y zeolite with two different SiO2/Al2O3 molar ratios (60 and 12) was evaluated for the first time in the removal of 25 pharmaceutical compounds (PhCs) present in real effluents from two municipal wastewater treatment plants both located in the Mediterranean coast of Spain. Additionally, control experiments including adsorption and direct ozonation, were conducted to better understand the fundamental aspects of the different individual systems in wastewater samples. Commercial zeolites were used in sodium form (NaY). The results showed that the simultaneous use of ozone and NaY zeolites significantly improved the micropollutants degradation rate, able to degrade 95 % of the total mixture of PhCs within the early 9 min using the zeolite NaY-12 (24.4 mg O3 L-1 consumed), while 12 min of reaction with the zeolite NaY-60 (31 mg O3 L-1 consumed). In the case of individual experiments, ozonation removed 95 % of the total mixture of PhCs after 25 min (46.2 mg O3 L-1 consumed), while the direct adsorption, after 60 min of contact time, eliminated 30 % and 44 % using the NaY-12 and NaY-60 zeolites, respectively. Results showed that the Brønsted acid sites seemed to play an important role in the effectiveness of the treatment with ozone. Finally, the environmental assessment showed that the total risk quotients of pharmaceuticals were reduced between 87 %-99 % after ozonation in the presence of NaY-60 and NaY-12 zeolites. The results of this study demonstrate that catalytic ozonation using NaY zeolites as catalysts is a promising alternative for micropollutant elimination in real-world wastewater matrices.

Ozonation using a stainless-steel membrane contactor: Gas-liquid mass transfer and pharmaceuticals removal from secondary-treated municipal wastewater.

A tubular porous stainless steel membrane contactor was characterized in terms of ozone-water mass transport, as well as its application in removing 23 pharmaceuticals (PhACs) detected in the secondary-treated municipal wastewater, under continuous mode operation. The volumetric mass transfer coefficient (KLa) was evaluated based on liquid flow rate, gas flow rate, and ozone gas concentration. The KLa values were substantially improved with an increment in liquid flow rate (1.6 times from 30 to 70 dm3 h-1) and gas flow rate (3.6 times from 0.30 to 0.85 Ndm3 min-1) due to the improved mixing in the gas-liquid interface. For the lowest liquid flow rate (30 dm3 h-1), the water phase boundary layer (82%) exhibited the major ozone transfer resistance, but it became almost comparable with membrane resistance for the highest liquid flow rate (70 dm3 h-1). Additionally, the influence of the specific ozone dose (0.39, 0.53, and 0.69 g O3 g DOC-1) and ozone inlet gas concentration ( [Formula: see text]  = 27, 80, and 134 g Nm-3) were investigated in the elimination of 23 PhACs found in secondary-treated municipal wastewater. An ozone dose of 0.69 g O3 g DOC-1 and residence time of 60 s resulted in the removal of 12 out of the 23 compounds over 80%, while 17 compounds were abated above 60%. The elimination of PhACs was strongly correlated with kinetic reaction constants values with ozone and hydroxyl radicals (kO3 and kHO•), leading to a characteristic elimination pattern for each group of contaminants. This study demonstrates the high potential of membrane contactors as an appealing alternative for ozone-driven wastewater treatment.

Cemetery Relocations in Hidroituango: An Interdisciplinary Study.

This study realized the exhumation and transfer of human remains buried in the cemeteries at Orobajo, Barbacoas and La Fortuna (Municipality of Sabanalarga, Peque and Buriticá respectively) within the framework of "Social Management" of the Ituango Hydroelectric Project and the program Integral Restitution of Living Conditions for communities. Methods and techniques from bioanthropology, forensic sciences, archeology and Soil Sciences were used. Cemeteries were characterized by unconventional burials; moreover, documentation of tombs and burial practices were not generalized, nor did they show patterns. In the field assessment, 2,883 pit tests and soil probes using a penetrometer were carried out over a total area of 2,288 square meters. A total of 349 skeletonized human remains were exhumed, almost double of what was expected; of these, 180 were from Orabajo, 151 from Barbacoas, and 18 from La Fortuna. Though the remains showed a great deal of deterioration, age at death was determined for 59% of cases, and sex identified in 49%. Personal artifacts and clothing items were recovered along with the bones in many cases. Remains from Barbacoas and La Fortuna were given over to communities, and final dispositions were made in sites previously agreed upon (cemeteries in Peque, Buriticá and Sabanalarga respectively).

Oil Bioremediation in a Tropical Contaminated Soil Using a Reactor.

This research was implemented in the Colombian Amazon forest area; to assess the effect of Tween-80® surfactant in the degradation of the Total Petroleum Hydrocarbons (TPH) in bioremediation treatments under aerobic conditions in the laboratory and pilot-scale. One control treatment, Natural Attenuation (AT) and four biostimulation treatments with leonardite with four different dosages of Tween-80® were proposed. The efficacy of organic stimulators and nonionic surfactant in soil microbiota was studied at laboratory and pilot scales, the latter in a passive aeration reactor. The test that presented a better performance was carried out with a Convective Flow Reactor (CFR) at pilot-scale. The results showed that bioremediation strategies improved the natural degradation process; the best outcomes were obtained in a treatment that includes Leonardite and Tween-80® (1.5 g/L) with 52% TPH degradation in 80 days (d).Tween-80® produced an effect in TPH solubility, and increased the production of CO2 in distinctive bioremediation treatments in both periods. The kinetics of CO2 production showed that the system required a periodic addition of a co-substrate as well as an increase of soil microbiota through the addition of compost (pilot scale). In this stage more than 76% of contaminant was degraded in 60d.