17 research outputs found
Assessment of Medical Waste Management in Educational Hospitals of Tehran University Medical Sciences
The management of medical waste is of great importance due to its
potential environmental hazards andpublic health risks. In the past,
medical waste was often mixed with municipal solid waste and disposed
inresidential waste landfills or improper treatment facilities in Iran.
In recent years, many efforts have beenmade by environmental regulatory
agencies and waste generators to better managing the wastes
fromhealthcare facilities. This study was carried in 12 educational
hospitals of Tehran University of MedicalSciences. The goals of this
study were to characterize solid wastes generated in healthcare
hospitals, toreport the current status of medical waste management and
to provide a framework for the safemanagement of these wastes at the
considered hospitals. The methodology was descriptive, cross-sectional
and consisted of the use of surveys and interviews with the authorities
of the healthcare facilities and with personnel involved in the
management of the wastes. The results showed that medical
wastesgenerated in hospitals were extremely heterogeneous in
composition. 42% of wastes were collected incontainers and plastic
bags. In 75% of hospitals, the stay-time in storage sites was about
12-24h. 92% ofmedical wastes of hospitals were collected by
covered-trucks. In 46% of hospitals, transferring of medicalwastes to
temporary stations was done manually. The average of waste generation
rates in the hospitalswas estimated to be 4.42kg/bed/day
Enhanced sono-photocatalysis of tetracycline antibiotic using TiO2 decorated on magnetic activated carbon (MAC@T) coupled with US and UV: A new hybrid system
A combined system including sonocatalysis and photocatalysis was applied for catalytic degradation of tetracycline (TC) antibiotic using TiO2 decorated on magnetic activated carbon (MAC@T) in coupling with ultraviolet (UV) and ultrasound (US) irradiations. MAC was fabricated via magnetization of AC using Fe3O4 nanoparticles. FESEM, EDS, TEM, BET, XRD, PL, VSM and UV�visible DRS techniques were used to characterize the catalyst features. The performance of MAC@T/UV/US system was examined under impact of different input variable such as catalyst loading, solution pH, initial TC concentration, US power, scavenging agents, chemical oxidants and co-exiting anions. The degradation rate was enhanced substantially when MAC@T coupled with US and UV irradiations. At optimal conditions, over 93 TC and 50 TOC were removed under 180 min reaction. Whereas, the complete removal of TC was obtained after 60 min treatment, when MAC@T/UV/US coupled with oxidants. Decreasing sequence of the inhibitory effect of anions was chloride > bicarbonate > phosphate > nitrate > sulfate. Both Fe leaching and loss of the decontamination were slight with reused times, indicating MAC@T has a high stability and reusability. According to trapping tests, holes, radOH and 1O2 were contributed in the degradation process. In conclusion, integration of MAC@T composite and US/UV for enhancing catalytic degradation efficiency can be introduced as a successful and promising technique, owing to excellent catalytic activity, easy recovery, good adsorption capacity and high durability and recycling potential. © 2019 Elsevier B.V
Comparative Study of SMBR and Extended Aeration Activated Sludge Processes in the Treatment of Strength Wastewaters
Background and Objectives: One of the complete treatment processes for industrial and municipal wastewater treatment is membrane bioreactor process which has dominant potential in process and operation sections. This study was conducted to compare the performance of extended aeration activated sludge (EAAS) with submerged membrane bioreactor (SMBR) systems in the treatment of strength wastewater, in the same condition. Materials and Methods: The initial activated sludge was brought from the Plascokar Saipa wastewater plant. The Plexiglas reactor with effective volume of 758 L was separated by a baffle into the aeration and secondary sedimentation parts with effective volumes of 433 L and 325 L, respectively. The chemical oxygen demand (COD) concentration of the influent wastewater of the EAAS and SMBR systems were between 500-2700 and 500-5000 mg/L, respectively.Results: Results showed that the SMBR system produced a much better quality effluent than EAAS system in terms of COD, biochemical oxygen demand (BOD5), total suspended solids (TSS) and ammonium. By increasing the COD concentration, the concentration of mixed liquor suspended solids (MLSS) and the removal efficiency of organic matter in the SMBR system, were increased regularly, however the removal efficiency of COD in the EAAS system was irregular. Conclusion: The average BOD5/COD ratio of effluent in the EAAS and SMBR systems were 0.708±0.18 and 0.537±0.106, respectively. These show that the organic matters in the effluent of the SMBR system was less degradable and thereupon more biological treatment was achieved. Nitrification process was completely done in the SMBR system while the EAAS system could not achieve to complete nitrification
Removal Of Hexavalent Chromium From Drinking Water By Granular Ferric Hydroxide
Removal of chromium can be accomplished by various methods but none of
them is cost-effective in meeting drinking water standards. For this
study, granular ferric hydroxide was used as adsorbent for removal of
hexavalent chromium. Besides, the effects of changing contact time, pH
and concentrations of competitive anions were determined for different
amounts of granular ferric hydroxide. It was found that granular ferric
hydroxide has a high capacity for adsorption of hexavalent chromium
from water at pH?7 and in 90 min contact time. Maximum adsorption
capacity was determined to be 0.788 mg Cr+6 /g granular ferric
hydroxide. Although relatively good adsorption of sulfate and chloride
had been specified in this study, the interfering effects of these two
anions had not been detected in concentrations of 200 and 400 mg/L. The
absorbability of hexavalent chromium by granular ferric hydroxide could
be expressed by Freundlich isotherm with R2 >0.968. However, the
disadvantage was that the iron concentration in water was increased by
the granular ferric hydroxide. Nevertheless, granular ferric hydroxide
is a promising adsorbent for chromium removal, even in the presence of
other interfering compounds, because granular ferric hydroxide
treatment can easily be accomplished and removal of excess iron is a
simple practice for conventional water treatment plants. Thus, this
method could be regarded as a safe and convenient solution to the
problem of chromium-polluted water resources