Polychlorinated Terphenyls (PCTs): Backbone Angle of ortho and nonortho Chlorination

Polychorinated Terphenyls is considered as one of persistent organic pollutants (POPs) and have been banned in the use mostly in United State and Europe countries. A study of the ortho chlorination toward backbone angle has been done in order to obtain the information of –C-C- angle of between aromatic groups of terphenyls. Five hexachlorinated terphenyl standards have been deployed for the purpose. Firstly, five terphenyl standards of 2,2",3,3",5,5"-hexachlorinated-meta-, 2',3,3",5,5',5"-hexachlorinated- para-, 2',3,3",4,4",5'-hexachlorinated-para-, 2,2”,3,3”,5,5”-hexachlorinaated-para-, 3,3´,3”,5,5´,5”-hexachlorinated-para- have been measured by GC-FTIR. From the data obtained, IR spectra of each standard were then compared to the theoretical calculation with Gaussian Program. The result showed that IR spectra of all five standard congeners were fit to the each spectra of the theoretical calculation. Based on the theoretical IR spectra obtained, furthermore, backbone angle of each five standards were able to be obtained related to the position of the chlorination pattern of the backbone. The angle between aromatics groups because of ortho chlorination or without ortho chlorination was clearly different. The ortho chlorination contributed to angle resulted in the lowest structure energy level around 51°-58°. Without ortho chlorination, the angle is around 36°

Life Cycle Assessment (LCA) Comparing Disinfection Options for Drinking Water Treatment

Drinking water treatment is essential to obtain a healthy source of water that can be distributed throughout a community. There are various methods to disinfect water, and all have trade-offs regarding public health and the environment. For example, chemical disinfectants that use chlorine can produce disinfection by-products within treated drinking water. The Environmental Protection Agency regulates these disinfection by-products because of their potential to cause cancer. Ultraviolet (UV) light is a physical disinfection method that does not produce these disinfection by-products, which is why it is becoming a preferred method for water treatment. For this research, I conducted a comparative life cycle assessment (LCA) for chemical and physical disinfection methods. The main factors considered within this LCA were energy consumption and human toxicity risk. The results from my research support my original hypothesis that the assessed chemical disinfection method had less energy consumption and a higher human toxicity risk compared to the assessed physical disinfection method. The results show that each method has trade-offs and that this LCA can provide extensive knowledge on which disinfection method would work best for the Bethlehem, New Hampshire community based on the stakeholders’ priorities

Investigating the removal of some pharmaceutical compounds in hospital wastewater treatment plants operating in Saudi Arabia

The concentrations of 12 pharmaceutical compounds (atenolol, erythromycin, cyclophosphamide, paracetamol, bezafibrate, carbamazepine, ciprofloxacin, caffeine, clarithromycin, lidocaine, sulfamethoxazole and Nacetylsulfamethoxazol (NACS)) were investigated in the influents and effluents of two hospital wastewater treatment plants (HWWTPs) in Saudi Arabia. The majority of the target analytes were detected in the influent samples apart from bezafibrate, cyclophosphamide, and erythromycin. Caffeine and paracetamol were detected in the influent at particularly high concentrations up to 75 and 12 ug/L, respectively. High removal efficiencies of the pharmaceutical compounds were observed in both HWWTPs, with greater than 90 % removal on average. Paracetamol, sulfamethoxazole, NACS, ciprofloxacin, and caffeine were eliminated by between >95 and >99 % on average. Atenolol, carbamazepine, and clarithromycin were eliminated by >86 % on average. Of particular interest were the high removal efficiencies of carbamazepine and antibiotics that were achieved by the HWWTPs; these compounds have been reported to be relatively recalcitrant to biological treatment and are generally only partially removed. Elevated temperatures and high levels of sunlight were considered to be the main factors that enhanced the removal of these compounds

Pilot scale study of chlorination-induced transport property changes of a seawater reverse osmosis membrane

A pilot-scale study was performed to assess variations of reverse osmosis (RO) membrane water permeance (A) and salt retention (Robs) induced by chlorination and to compare them with those observed at the lab-scale. A chlorination protocol was adapted to expose only the surface active layer (an aromatic polyamide)of a composite RO membrane to consecutive free chlorine doses ranging from 40 to 4000 ppm h, at pH 6.9. Along the long-term filtration of seawater, performed with a 4" spiral wound RO module, we monitored the variations of A, the decrease of Robs and the rate of increase of A with time, and found themquantitatively similar to those reported in previous studies performed at the lab-scale under accelerated exposure conditions. The elemental analysis of the feed and permeate streams revealed that the rejection of divalent ions remained constant (ca. 100%), irrespective of the free chlorine dose reached, whereas the rejection of monovalent ions of the seawater (mainly sodium, chloride and bromide ions) decreased as the exposure dose increased. Overall, transposing the characterization procedure to the pilot-scale further supports that chlorination of PA, under pH conditions usually found in desalination plants (6.9 to 8.0), is controlled by the concentration of HOCl, as observed from elemental analysis of the surface by XPS

Contribution of the antibiotic chloramphenicol and its analogues as precursors of dichloroacetamide and other disinfection byproducts in drinking water

Dichloroacetamide (DCAcAm), a disinfection byproduct, has been detected in drinking water. Previous research showed that amino acids may be DCAcAm precursors. However, other precursors may be present. This study explored the contribution of the antibiotic chloramphenicol (CAP) and two of its analogues (thiamphenicol, TAP; florfenicol, FF) (referred to collectively as CAPs), which occur in wastewater-impacted source waters, to the formation of DCAcAm. Their formation yields were compared to free and combined amino acids, and they were investigated in filtered waters from drinking-water-treatment plants, heavily wastewater-impacted natural waters, and secondary effluents from wastewater treatment plants. CAPs had greater DCAcAm formation potential than two representative amino acid precursors. However, in drinking waters with ng/L levels of CAPs, they will not contribute as much to DCAcAm formation as the μg/L levels of amino acids. Also, the effect of advanced oxidation processes (AOPs) on DCAcAm formation from CAPs in real water samples during subsequent chlorination was evaluated. Preoxidation of CAPs with AOPs reduced the formation of DCAcAm during postchlorination. The results of this study suggest that CAPs should be considered as possible precursors of DCAcAm, especially in heavily wastewater-impacted waters

Recovery of actinides from actinide-aluminium alloys by chlorination: Part I

Pyrochemical processes in molten LiCl–KCl are being developed in ITU for recovery of actinides from spent nuclear fuel. The fuel is anodically dissolved to the molten salt electrolyte and actinides are electrochemically reduced on solid aluminium cathodes forming solid actinide–aluminium alloys. A chlorination route is being investigated for recovery of actinides from the alloys. This route consists in three steps: Vacuum distillation for removal of the salt adhered on the electrode, chlorination of the actinide– aluminium alloys by chlorine gas and sublimation of the formed AlCl3. A thermochemical study showed thermodynamic feasibility of all three steps. On the basis of the conditions identified by the calculations, experiments using pure UAl3 alloy were carried out to evaluate and optimise the chlorination step. The work was focused on determination of the optimal temperature and Cl2/UAl3 molar ratio, providing complete chlorination of the alloy without formation of volatile UCl5 and UCl6. The results showed high efficient chlorination at a temperature of 150 °C

Heterogeneity in the Relationship between Disinfection By-Products in Drinking Water and Cancer: A Systematic Review.

The epidemiological evidence demonstrating the effect of disinfection by-products (DBPs) from drinking water on colon and rectal cancers is well documented. However, no systematic assessment has been conducted to assess the potential effect measure modification (EMM) in the relationship between DBPs and cancer. The objective of this paper is to conduct a systematic literature review to determine the extent to which EMM has been assessed in the relationship between DBPs in drinking water in past epidemiological studies. Selected articles (n = 19) were reviewed, and effect estimates and covariates that could have been used in an EMM assessment were gathered. Approximately half of the studies assess EMM (n = 10), but the majority of studies only estimate it relative to sex subgroups (n = 6 for bladder cancer and n = 2 both for rectal and colon cancers). Although EMM is rarely assessed, several variables that could have a potential modification effect are routinely collected in these studies, such as socioeconomic status or age. The role of environmental exposures through drinking water can play an important role and contribute to cancer disparities. We encourage a systematic use of subgroup analysis to understand which populations or territories are more vulnerable to the health impacts of DBPs

A Systematic Review of the Evidence for the Sustainability of Household Water Treatment Interventions

This systematic review assesses the quantity and quality of evidence for the sustainability of household water treatment (HWT) since the World Health Organization (WHO) recently endorsed HWT based on growing evidence of HWT's ability to improve microbial water quality, effectiveness at reducing diarrheal disease, cost-effectiveness, and rapid application and acceptance. A large portion of the world population still relies on unsafe sources of drinking water, but whether HWT can support scaling-up efforts and be considered sustainable, it remains to be seen. Ultimately this systematic review found limited evidence of a sustained uptake and usage of HWT interventions, and results from studies that found high levels of confirmed usage after one year must be considered alongside their methodological quality