Saad Jasim

Endocrine disrupting compounds (EDCs) and pharmaceuticals and personal care products (PPCPs) in the aquatic environment: implications for the drinking water industry and global environmental health

Endocrine disrupting compounds (EDCs) and pharmaceuticals and personal care products (PPCPs) are a group of chemical compounds with diverse physical and chemical properties. Recent studies have indicated undesired effects of EDCs and PPCPs at their reported trace concentrations (ng l(-1) to microg l(-1)). This paper reviews the current knowledge on the sources, properties, occurrence and health impacts of EDCs and PPCPs, and their removal from drinking water using ozonation and ozone/hydrogen peroxide-based advanced oxidation. The paper also examines the potential threats posed by these chemicals to drinking water and public health. While these compounds are known to have adverse effects on ecosystem health, notably in the fish population, a similar link is yet to be established between ingestion of these compounds through drinking water and human health. In addition, data on the effectiveness of existing methods for the removal of these compounds are not conclusive. Further studies are required to characterize risks, and also to evaluate and optimize existing removal processes. Also concerted international effort is urgent to cut down the risk of exposure and restrain the production and marketing of toxic chemicals.

Presence of Pharmaceuticals and Pesticides in Detroit River Water and the Effect of Ozone on Removal

Reports by different scientific groups indicate concern about traces of drugs that could make their way into tap water. Studies indicate that activated carbon and ozone are promising treatment methods to remove traces of pharmaceuticals and pesticides. The Windsor Utilities Commission (WUC), Windsor, Ontario, Canada, evaluated the occurrence of pharmaceuticals and endocrine disrupting chemicals in its raw water supply, and the effectiveness of ozone in removing these compounds. The analysis indicated that trace levels of compounds such as carbamazepine, caffeine, cotinine, and atrazine were detected in raw water and that treatment with ozone resulted in a greater removal versus conventional treatment.

Advanced Oxidation Treatment of Drinking Water: Part I. Occurrence and Removal of Pharmaceuticals and Endocrine-Disrupting Compounds from Lake Huron Water

The current study focuses on the occurrence of selected endocrine disrupting compounds, pharmaceuticals and personal care products in Lake Huron Water and their removal using ozone/hydrogen peroxide based pre-coagulation, advanced oxidation process (AOP). Raw Lake Huron water spiked with nine target compounds was treated in a dual train pilot scale treatment plant. None of the target chemicals showed any significant removals following conventional treatment processes (coagulation, sedimentation and filtration). Five of the nine target pollutants plummeted to concentrations below the method detection limits following AOP. For all the target compounds AOP treatment provided higher removal compared to conventional treatment.

A Survey of Occurrence and Risk Assessment of Pharmaceutical Substances in the Great Lakes Basin

The present study is an overview of the literature on the occurrence and potential risks of pharmaceutical substances in the wastewater treatment plants (WWTP), natural waters and drinking water treatment plants served by the Great Lakes Basin (Canada and the USA) between the years of 2007–2012. Large number of pharmaceutical substances, including anti-inflammatories, lipid regulators, antidepressants, antibiotics, beta blockers, anti-epileptics, anti-hypertensions and stimulants, in high ng/L concentrations, has been reported in the WWTP influents. Most of these compounds have also been detected in the WWTP effluents at comparable concentrations with the exception of caffeine, cotinine and salicylic acid suggesting the inefficiency of conventional treatment processes in the degradation of pharmaceutical compounds. Decreasing surface water concentrations have been observed with the distance downstream of the discharge point due to the dilution effect. Surface waters located around septic systems and agricultural areas have also been found to be contaminated with pharmaceutical substances. Carbamazepine, caffeine, its metabolite paraxanthine, ibuprofen, gemfibrozil and sulfamethoxazole have been frequently detected in the surface waters. The number of occurrences of carbamazepine, ibuprofen, naproxen, gemfibrozil, bezafibrate, sulfamethoxazole and macrolide antibiotics in drinking water sources, at ng/L concentration ranges, has been quite high. Although the detection frequencies in treated drinking waters were relatively low, the concentrations of the above mentioned pharmaceutical substances were at the same range as the source water concentrations. Six of the detected pharmaceutical substances, namely, fluoxetine, sulfamethoxazole, clarithromycin, erythromycin, carbamazepine and esterone exhibit a high environmental risk in Great Lakes WWTP effluents and surface waters, while none of the pharmaceutical substances seem to pose a risk for human health at their highest reported concentrations in the drinking water sources from the Great Lakes.

Advanced Oxidation Treatment of Drinking Water: Part II. Turbidity, Particles and Organics Removal from Lake Huron Water

Pre-coagulation ozonation has been reported to be effective in drinking water treatment processes. Limited data are available on the impact of advanced oxidation processes (AOPs) on Lake Huron water which serves as a primary source of drinking water for many communities around the Great Lakes region. Impact of ozone/hydrogen peroxide based AOP on Lake Huron water was studied. The results show that AOPs can achieve higher particles removal in finished water and deliver improved filtered water turbidity compared to the conventional treatment process. Sharp decline in ultraviolet absorbance at 254 nm (UV254) was observed immediately following AOP treatment while only minimal overall decrease in dissolved organic carbon (DOC) was achieved.

The Effect of Ozone on Cold Water Coagulation

The application of pre-coagulation ozone in drinking water treatment to provide primary disinfection, has an impact on coagulation and flocculation, and needs to be evaluated further for cold water temperatures, especially when accompanied by episodes of high alkalinity and dissolved organic carbon (DOC). Ozone application to raw water, prior to the addition of coagulants and coagulant aides, was shown to reduce coagulant and coagulant aide doses, and improve settled and filtered water turbidity. The impact on particle count was also noticeable, filtered water particle count was reduced after the application of pre-coagulation ozonation. Pilot-scale experiments were conducted at the Walkerton Clean Water Centre, Walkerton, Ontario, Canada, to investigate the effect of pre-coagulation ozonation, on filtered water turbidity, particle count, and filter performance, during periods when water temperatures could be lower than 5°C.

Bromate Formation in Ozone and Advanced Oxidation Processes

Both the direct ozone reaction and the indirect hydroxyl radical reaction are important in ozonation of drinking water. This article investigates the effectiveness of ozone versus the advanced oxidation process of ozone coupled with hydrogen peroxide in the formation of bromate. The investigation was conducted on a pilot scale at various H2O2:O3 dose ratios of 0.1, 0.2, and 0.35 at different times of the year. The results of this study show a reduction in bromate with the addition of hydrogen peroxide to an ozone system versus ozone alone. It was also observed that bromate increased with increased H2O2:O3 ratios; however, concentrations were still lower than those in the ozone only system.

Impact of Ozone and Hydrogen Peroxide vs. UV and Hydrogen Peroxide on Chlorine Residual

The current study undertaken by the Walkerton Clean Water Centre (WCWC) is to evaluate the application of Advanced Oxidation Processes (AOPs) involving Ozone and UV with the addition of hydrogen peroxide, as one of the methods used in the process of the removal of PPCPs and EDCs, or taste and odor. The amount of hydrogen peroxide used with UV is much higher than that used with the ozone application. The concern is the impact of the hydrogen peroxide on the chlorine residual in the water that is pumped to the distribution system. One of the methods used to deal with this problem is to increase the chlorine addition to maintain the required residual. That could increase the disinfectant by-products (DBPs), namely Trihalomethanes (THMs), in addition to increase to the cost of operation. The findings of these experiments would provide useful information regarding the AOPs application using ozone vs. UV with hydrogen peroxide.

Improvement and Optimization of the A. H. Weeks Water Treatment Plant Processes, Windsor, ON, Canada

ABSTRACT After the ozone system was implemented at the A.H.Weeks Water Treatment Plant in June 2001, the plant was monitored to evaluate the effects that ozone had on the plant operation and filtered water quality. Filter performance showed an improvement since ozone was applied. Longer filter run time and lower filtered water turbidity and particle count were achieved. Average treated water turbidity was 0.07 NTU for the year before ozone was applied and 0.05 NTU for the year after ozone was applied. An optimization process was conducted to improve the operation. The benefits of the ozone system optimization resulted in more consistency in meeting performance objectives. Ozone generator power requirement was decreased while ozone generator efficiency was increased. Overdosing of ozone quenching agent was less frequent. Reduction in total operational cost was also observed for the year ozone was applied.

Reaction Kinetics of Ozone with Selected Pharmaceuticals and Their Removal Potential from a Secondary Treated Municipal Wastewater Effluent in the Great Lakes Basin

Oxidation kinetics of selected pharmaceutical compounds and their degradation during ozonation of secondary treated municipal wastewater effluent (MWWE) was investigated. The apparent second-order rate constants for the reaction between chlorotetracycline (CTC), enrofloxacin (ENR), gemfibrozil (GEM) and ozone ranged between 6.82 – 52.7 × 104 M−1s−1. The measured second-order hydroxyl radical rate constants were several orders of magnitude higher at 8.4 × 109 – 13.1 × 109 M−1s−1 with a reactivity sequence of GEM > CTC > ENR. Overall degradation of CTC, ENR and GEM in secondary treated municipal wastewater effluent was >76 % at ozone doses of 0.33 mg O3/mg DOC or higher.