scholarly journals Modelling PAHs removal in activated sludge process: effect of disintegration

2019 ◽  
Vol 80 (4) ◽  
pp. 794-805
Author(s):  
I. Mozo ◽  
M. Bounouba ◽  
E. Mengelle ◽  
N. Lesage ◽  
M. Sperandio ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Activated Sludge ◽  
Aromatic Hydrocarbons ◽  
Suspended Matter ◽  
Activated Sludge Process ◽  
Mass Balances ◽  
Colloidal Matter ◽  
Main Driver ◽  
Polycyclic Aromatic

Abstract The removal of polycyclic aromatic hydrocarbons (PAHs) in activated sludge was evaluated using two laboratory-scale bioreactors, coupled or not with a disintegration system (sonication). Mass balances performed on each system underlined that PAHs removal was significantly improved after sludge disintegration, especially for the higher molecular weight PAHs studied, which tended to adsorb to suspended matter. A model was developed in order to study the effect of sludge disintegration on the content of dissolved and colloidal matter (DCM), and to predict the potential impacts on PAHs availability and degradation. Results showed that this new model was efficient for capturing apparent degradation improvement trends and for discriminating between the involved mechanisms. This study showed that DCM content increased after sludge disintegration, and proved to be the main driver for improving PAHs apparent degradation.

scholarly journals Comparison of ΣLMW Utilization Rate from Saline Wastewater in SBR Reactors with Granular and Flocked Activated Sludge

Proceedings ◽  
2019 ◽  
Vol 16 (1) ◽  
pp. 17
Author(s):  
Ofman ◽  
Skoczko
Keyword(s):  
Molecular Weight ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Activated Sludge ◽  
Aromatic Hydrocarbons ◽  
Oxygen Demand ◽  
Biological Oxygen Demand ◽  
Utilization Rate ◽  
Low Molecular Weight ◽  
Saline Wastewater ◽  
Polycyclic Aromatic

Paper discuses changes in utilization rate of Low Molecular Weight polycyclic aromatic hydrocarbons PAHs in sequencing bath reactors (SBR) operating with flocked and aerobic granular activated sludge. Studies were carried out in laboratory scale SBR reactors filled with model wastewater characterized by salinity at level 4.00 g·dm−3. Wastewater inflowing to laboratory reactors was characterized by varying biological oxygen demand (BOD) load in the range of 0.05–1.60 kg BOD·kg−1·d−1.

scholarly journals Polycyclic Aromatic Hydrocarbons in Indoor Dust Collected during the COVID-19 Pandemic Lockdown in Saudi Arabia: Status, Sources and Human Health Risks

2021 ◽  
Vol 18 (5) ◽  
pp. 2743
Author(s):  
Sultan Hassan Alamri ◽  
Nadeem Ali ◽  
Hussain Mohammed Salem Ali Albar ◽  
Muhammad Imtiaz Rashid ◽  
Nisreen Rajeh ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Saudi Arabia ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Human Health ◽  
Aromatic Hydrocarbons ◽  
Indoor Environment ◽  
Indoor Dust ◽  
Environment Quality ◽  
Indoor Environment Quality ◽  
Polycyclic Aromatic

To control the spread of coronavirus disease (COVID-19), Saudi Arabia’s government imposed a strict lockdown during March–July 2020. As a result, the public was confined to indoors, and most of their daily activities were happening in their indoor places, which might have resulted in lower indoor environment quality. Polycyclic aromatic hydrocarbons (PAHs) were analyzed in household dust (n = 40) collected from different residential districts of Jeddah, Saudi Arabia, during the lockdown period. PAHs’ levels were two folds higher than the previously reported PAHs in indoor dust from this region. We detected low molecular weight (LMW) with two to four aromatic ring PAHs in all the samples with a significant contribution from Phenanthrene (Phe), present at an average concentration of 1590 ng/g of dust. Although high molecular weight (HMW) (5–6 aromatic ring) PAHs were detected at lower concentrations than LMW PAHs, however, they contributed >90% in the carcinogenic index of PAHs. The estimated daily intake (EDI) of specific PAHs was above the reference dose (RfD) for young children in high-end exposure and the calculated Incremental Lifetime Cancer Risk (ILCR) was >1.00 × 10−4 for both Saudi adults and young children. The study highlighted that indoor pollution has increased significantly during lockdown due to the increased indoor activities and inversely affect human health. This study also warrants to conduct more studies involving different chemicals to understand the indoor environment quality during strict lockdown conditions.

scholarly journals The Most Important Methods for Depollution of Hydrocarbons Polluted Soils

1970 ◽  
Vol 66 (1) ◽  
Author(s):  
Laura DOBOS ◽  
Carmen PUIA
Keyword(s):  
Molecular Weight ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Heterocyclic Compounds ◽  
Chemical Structure ◽  
Complex Mixture ◽  
Naphthenic Acids ◽  
International Agency ◽  
Polluted Soils ◽  
Polycyclic Aromatic

Crude oil is a highly complex mixture of hydrocarbons amounting to hundreds of individual compounds with different chemical structure and molecular weight plus a series of lower molecular weight compounds other than hydrocarbons (phenols, thiols, naphthenic acids, heterocyclic compounds with N (pyridines, pyrrole, indole, s.o.) compounds S (alkyl thiols, thiophene, etc.) (Zarnea, 1994). Mineral oil and polycyclic aromatic hydrocarbons (PAHs) creates larger environmental problems. They are considered particularly dangerous. In this regard, EPA Agency from U.S.A. includes a number of polycyclic aromatic hydrocarbons under 16 priority pollutants, which require special attention. IARC (International Agency for Research on Cancer) has identified 15 types of polycyclic aromatic hydrocarbons including six of the 16 types of PAHs, identifiable by the USEPA as having carcinogenic properties (Chauhan Archana et al., 2008).

scholarly journals Degradation of Polycyclic Aromatic Hydrocarbons by Moderately Halophilic Bacteria from Luzon Salt Beds

2018 ◽  
Vol 8 (19) ◽  
Author(s):  
Carolyn L. Nanca ◽  
Kimberly D. Neri ◽  
Anna Christina R. Ngo ◽  
Reuel M. Bennett ◽  
Gina R. Dedeles
Keyword(s):  
Molecular Weight ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Halophilic Bacteria ◽  
Sole Source ◽  
The Philippines ◽  
Liquid Fuels ◽  
Gram Positive ◽  
Gram Negative ◽  
Polycyclic Aromatic

Background. Polycyclic aromatic hydrocarbons (PAHs) are common environmental contaminants which are highly toxic due to their carcinogenic and mutagenic effects. They are released into the environment by incomplete combustion of solid and liquid fuels, accidental spillage of oils and seepage from industrial activities. One of the promising processes mitigating PAHs is through biodegradation. However, conventional microbiological treatment processes do not function well at high salt concentrations. Hence, utilization of halophilic bacteria should be considered. Objectives. This study aimed to assess the ability of halophilic bacteria isolated from local salt beds in Pangasinan and Cavite, the Philippines, to degrade PAHs pyrene, fluorene and fluoranthene. Methods. Polycyclic aromatic hydrocarbon-tolerant halophilic bacteria collected from two sampling sites were phenotypically characterized, molecularly identified and tested to determine their potential to degrade the PAHs pyrene, fluorene and fluoranthene at a hypersaline condition. Best PAH degraders were then assayed to identify the optimal degradation using such parameters as pH, temperature and PAH concentration. Testing for enzyme degradation was also done to determine their baseline information. Extraction and analysis of degraded PAHs were performed using centrifugation and UV-vis spectrophotometry. Results. Twelve isolates from both collection sites tolerated and grew in culture with selected PAHs. These were identified into four genera (Halobacillus, Halomonas, Chromohalobacter, and Pontibacillus). Selected best isolates in a series of biodegradation assays with the above-mentioned parameters were Halobacillus B (Collection of Microbial Strains (CMS) 1802) (=trueperi) (Gram-positive) for pyrene and fluoranthene, and Halomonas A (CMS 1901) (Gram-negative) for fluorene. Degrader biomass and PAH degradation were invariably negatively correlated. Qualitative tests with and without peptone as a nitrogen source implied enzymatic degradation. Discussion. Polycyclic aromatic hydrocarbons utilized by these halophilic bacteria served as a sole source of carbon and energy. Implications of biodegradation of the two best isolates show that high molecular weight (HMW) (4-ring) pyrene tends to be degraded better by Gram-positive bacteria and low molecular weight (3-ring) fluorene by Gram-negative degraders. Conclusions. Halophilic bacteria constitute an untapped natural resource for biotechnology in the Philippines. The present study demonstrated their potential use in bioremediation of recalcitrant hydrocarbons in the environment. Competing Interests. The authors declare no competing financial interests.

scholarly journals Polycyclic Aromatic Hydrocarbons in PM2.5 and PM2.5–10 in Urumqi, China: Temporal Variations, Health Risk, and Sources

Atmosphere ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 412 ◽  
Author(s):  
Suwubinuer Rekefu ◽  
Dilinuer Talifu ◽  
Bo Gao ◽  
Yusan Turap ◽  
Mailikezhati Maihemuti ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Coal Combustion ◽  
Temporal Variations ◽  
Diagnostic Ratios ◽  
Positive Matrix ◽  
Increasing Trend ◽  
Polycyclic Aromatic ◽  
The Mean

PM2.5 and PM2.5–10 samples were simultaneously collected in Urumqi from January to December 2011, and 14 priority polycyclic aromatic hydrocarbons (PAHs) were determined. The mean concentrations of total PAHs in PM2.5 and PM2.5–10 were 20.90~844.22 ng m−3 and 19.65~176.5 ng m−3 respectively, with the highest in winter and the lowest in summer. Above 80% of PAHs were enriched in PM2.5, which showed remarkable seasonal variations compared to coarse particles. High molecular weight (HMW) PAHs were predominant in PM2.5 (46.61~85.13%), whereas the proportions of lower molecular weight (LMW) and HMW PAHs in PM2.5–10 showed a decreasing and an increasing trend, respectively, from spring to winter. The estimated concentrations of benzo[a]pyrene equivalent carcinogenic potency (BaPeq) in PM2.5 (10.49~84.52 ng m−3) were higher than that of in PM2.5–10 (1.15~13.33 ng m−3) except in summer. The estimated value of inhalation cancer risk in PM2.5 and PM2.5–10 were 1.63 × 10−4~7.35 × 10−3 and 9.94 × 10−5~1.16 × 10−3, respectively, far exceeding the health-based guideline level of 10−4. Diagnostic ratios and positive matrix factorization results demonstrated that PAHs in PM2.5 and PM2.5–10 were from similar sources, such as coal combustion, biomass burning, coking, and petroleum combustion, respectively. Coal combustion was the most important source for PAHs both in PM2.5 and PM2.5–10, accounting for 54.20% and 50.29%, respectively.

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