Mahmoud Al-Hindi

Environmental risk analysis and prioritization of pharmaceuticals in a developing world context

The impact of residual pharmaceuticals on the aquatic environment has gained widespread attention over the past years. Various studies have established the occurrence of pharmaceutical compounds in different water bodies throughout the world. In view of the absence of occurrence data in a number of developing world countries, and given the limited availability of analytical resources in these countries, it is prudent to devise methodologies to prioritize pharmaceuticals for environmental monitoring purposes that are site specific. In this work, several prioritization approaches are used to rank the 88 most commonly consumed pharmaceuticals in Lebanon. A simultaneous multi-criteria decision analysis method utilizing the exposure, persistence, bioaccumulation, and toxicity (EPBT) approach is applied to a smaller subset of the original list (69 pharmaceuticals). Several base cases are investigated and sensitivity analysis is applied to one of these base case runs. The similarities and differences in the overall ranking of individual, and classes of, pharmaceuticals for the base cases and the sensitivity runs are elucidated. An environmental risk assessment (ERA), where predicted environmental concentrations (PEC) and risk quotients (RQ) are determined at different dilution factors, is performed as an alternative method of prioritization for a total of 84 pharmaceuticals. The ERA results indicate that metformin and amoxicillin have the highest PECs while 17β-estradiol, naftidrofuryl and dimenhydrinate have the highest RQs. The two approaches, EPBT prioritization and ERA, are compared and a priority list consisting of 26 pharmaceuticals of various classes is developed. Nervous system and alimentary tract and metabolism pharmaceuticals (9/26 and 5/26 respectively) constitute more than half of the numbers on the priority list with the balance consisting of anti-infective (4/26), musculo-skeletal (3/26), genito-urinary (2/26), respiratory (2/26) and cardiovascular (1/26) pharmaceuticals. This list will serve as a basis for the selection of candidate compounds to focus on for future monitoring campaigns.

Hollow fiber vs. flat sheet MBR for the treatment of high strength stabilized landfill leachate.

The Membrane Bioreactor (MBR) technology is increasingly becoming a prominent process in the treatment of high-strength wastewater such as leachate resulting from the decomposition of waste in landfills. This study presents a performance comparative assessment of flat sheet and hollow fiber membranes in bioreactors for the treatment of relatively stable landfill leachate with the objective of defining guidelines for pilot/full scale plants. For this purpose, a laboratory scale MBR system was constructed and operated to treat a leachate with Chemical Oxygen Demand (COD) (3900-7800mg/L), Biochemical Oxygen Demand (BOD5) (∼440-1537mg/L), Total Phosphorus (TP) (∼10-59mg/L), Phosphate (PO4(3)(-)) (5-58mg/L), Total Nitrogen (TN) (1500-5200mg/L), and ammonium (NH4(+)) (1770-4410mg/L). Both membranes achieved comparable BOD (92.2% vs. 93.2%) and TP (79.4% vs. 78.5%) removals. Higher PO4(3)(-) removal efficiency or percentage (87.3% vs. 81.3%) and slightly higher, but not statistically significant, COD removal efficiency were obtained with the hollow fiber membrane (71.4% vs. 68.5%). On the other hand, the flat sheet membrane achieved significantly higher TN and NH4(+) removal efficiencies (61.2% vs. 49.4% and 63.4% vs. 47.8%, respectively), which may be attributed to the less frequent addition of NaOCl compared to the hollow fiber system.

A solar still desalination system with enhanced productivity

AbstractIncreasing the productivity of solar stills has been the focus of intensive research. Many introduced developments, however, require complex components and entail notable increases in cost and land requirements. Developing a compact, productive, and easy-to-operate system is a main challenge. This paper describes a sustainable modification of the solar still that significantly enhances its productivity without forsaking its basic features. A simple amendment in the form of a slowly rotating drum is introduced allowing the formation of thin water films that evaporate rapidly and are continually renewed. The performance of this system was compared against a control without the introduced drum. Throughout the experiment, the new system gave considerably higher yield than the control with an average increase in daily productivity of 200%. Moreover, during sunshine hours, the increase in yield could surpass 6–8 times that of the control. Important parameters such as ease of handling, material availabil...

The use of activated carbon for the removal of pharmaceuticals from aqueous solutions: a review

The presence of pharmaceutically active compounds in surface and ground water is of concern due to the adverse effects they may have on human health, aquatic life, and the environment, emphasizing the importance of their removal from the water compartment. Activated carbon adsorption has proven to be effective for the removal of several types of inorganic and organic contaminants either as a stand-alone polishing step or in combination with other conventional and advanced water and wastewater treatment systems. This paper discusses the current status of the removal of pharmaceuticals from water using activated carbon derived from numerous precursors, providing an in-depth review of the multitude of factors (adsorbent properties, adsorbate properties, operating conditions) affecting the adsorption process, from the preparation of the activated carbon to its regeneration. A critical assessment of the existing literature is presented, highlighting research and development needs that may ultimately lead to a more comprehensive and sustainable use of activated carbon for the removal of pharmaceuticals from the water environment.

The effect of fast mixing conditions on the coagulation–flocculation process of highly turbid suspensions using liquid bittern coagulant

AbstractThe effect of fast mixing on floc formation and pollutant removal, using magnesium hydroxide as a coagulant, was investigated through characterization of relative strength and size of the formed flocs while operating at different mixing speeds and mixing times using a dynamic optical monitoring apparatus, and photometric dispersion analyzer (PDA2000). The parameters investigated included fast mixing speed (80, 100, and 120 rpm) and time (20, 40, and 60 s). Highly turbid kaolin clay suspensions (1213 ± 36 NTU) were alkalized using sodium hydroxide (NaOH) to pH values of 10.51 ± 0.02 at temperatures 20.7 ± 0.1°C, and liquid bittern (LB) was used as a coagulant. Fast mixing time had a clear effect on the flocs resistance to applied shear during the slow mixing phase. For all fast mixing times, 120 rpm caused the formation of largest flocs. Stronger flocs, indicated by the least change in flocculation index with time, required 60 s to form at all fast mixing speeds. Turbidity and TSS removal efficienc...

Assessment of Household Disposal of Pharmaceuticals in Lebanon: Management Options to Protect Water Quality and Public Health.

Pharmaceuticals comprise an extensive group of compounds whose release into the environment has potential adverse impacts on human health and aquatic ecosystems. In many developing countries the extent of the problem and the occurrence of pharmaceuticals in water bodies are generally unknown. While thousands of tons of pharmaceutical substances are used annually, little information is known about their final fate after their intended use. This paper focuses on better understanding the management of human-use pharmaceutical wastes generated at the residential level within the Administrative Beirut Area. A survey encompassing 300 households was conducted. Results revealed that the majority of respondents were found to dispose of their unwanted medications, mainly through the domestic solid waste stream. Willingness to participate in a future collection program was found to be a function of age, medical expenditure, and the respondents’ views towards awareness and the importance of establishing a collection system for pharmaceutical wastes. Respondents who stated a willingness to participate in a collection program and/or those who believed in the need for awareness programs on the dangers of improper medical waste disposal tended to favor more collection programs managed by the government as compared to a program run by pharmacies or to the act of re-gifting medication to people in need. Ultimately, collaboration and coordination between concerned stakeholders are essential for developing a successful national collection plan.

Removal of fouling species from brackish water reverse osmosis reject stream

ABSTRACT Brine disposal from reverse osmosis (RO) systems remains a major challenge for the desalination industry especially in inland areas where discharge options are very limited. Solutions will entail the introduction of economic treatment processes that will alleviate the brine’s negative impact on the environment and reduce its discharge volume. Such processes could act as an intermediary treatment process for the recycling of the brine through an additional RO stage which, for brackish water (BW) desalination, could lead to saving valuable water while reducing the amount of brine discharge. In this context, the study at hand attempts to evaluate the effectiveness of a one-step chemical process for the treatment of BWRO brine. This study seeks to determine optimal operating conditions relative to type, ratio, and dosage of alkalizing chemicals, pH and temperature, for substantially reducing the concentrations of scaling parameters such as calcium, magnesium, silica, and strontium. The results indicate that precipitation softening at pH = 11.5 using combined chemical dosages of NaOH and Na2CO3 in a ratio of 2:1 leads to substantial removal of calcium and magnesium (>95%) and moderately high removal of strontium and silica (>71%). GRAPHICAL ABSTRACT

The fate of selected pharmaceuticals in solar stills: Transfer, thermal degradation or photolysis?

The increase in demand for, and disposal of, pharmaceuticals, positively correlated with the growing human population, has led to the emergence of contaminants with high environmental and health impacts. Several developing countries that endure problems related to water sufficiency and/or quality resort to the use solar stills as an affordable water treatment method. This research is aimed at investigating the fate of five chemically distinct pharmaceuticals that might pervade solar stills; ibuprofen (IBU), diclofenac (DCF), carbamazepine (CBZ), ampicillin (AMP) and naproxen (NPX). The experiments were conducted under three conditions. The first condition studied the combined effect of temperature and light in simulated field-test-scale solar stills. The effect of temperature as a sole variable was investigated in the second while the third condition studied the effect of light only via concentrated solar power (CSP). Results show that distillates from solar stills did not contain the parent compounds for four out of the five pharmaceuticals. IBU was the only pharmaceutical that showed a transfer via vapor into the distillate with the highest recorded transfer percentage of 2.1% at 50°C when subjected to temperature alone and 0.6% under the combined effect of temperature and light. In the case of NPX and DCF, the parent compounds did not undergo transfer into the distillate phase; however their degradation by-products did. In addition, the results also showed that in the case of NPX, IBU and CBZ both high temperatures and sunlight combined were required to attain noticeable degradation. CSP accelerated the degradation of DCF, NPX and IBU with a three-minutes-degradation percentage of 44%, 13% and 2% respectively.

Activated carbon prepared from crushed pine needles used for the removal of Ni and Cd

AbstractA new activated carbon (AC), prepared by carbonization and chemical activation of crushed pine needles, was characterized and examined for its potential in removing two heavy metals, namely Nickel (Ni) and Cadmium (Cd). Fixed-bed column testing procedure was adopted in the study. Depending on the individual metal tested, different initial solution pH values and different initial metal concentrations were used to evaluate their impacts on the AC adsorption process. Breakthrough curves were used to assess the adsorption capacities. Batch reaction tests were also conducted and the resulting data were fitted to adsorption isotherms. Furthermore tests were conducted where the two metals were combined in the test samples so as to determine their synergistic effect. The results indicated that the highest metal removals and adsorption capacities were attained at the highest pH values and concentrations tested for each of the two metals. Also, the results recorded for the batch experiments exhibited higher...

Factors influencing the reuse of reclaimed water as a management option to augment water supplies

The reuse of treated wastewater, whether direct or indirect, can raise public concerns as a result of the overall risk perception. As such, community acceptance plays a significant role in the implementation of alternative water systems. Public attitudes towards water reuse are highly influenced by perceived health risk, religious prohibition, political issues, and the degree of human contact with recycled water. In most of the Mediterranean countries, wastewater is reused to different extents either within planned or unplanned schemes. Unfortunately, there are few in-depth studies of the socio-cultural aspects of reuse projects in developing countries, and Lebanon is no exception. Accordingly, this research will comprehensively tackle the issue of public knowledge, perceptions, and acceptance from different perspectives in an effort to provide national baseline information on wastewater reuse that is needed for future regulatory and developmental projects. As such, a survey was developed, tested, and administered. Results showed an inverse relation between the degree of human contact with the treated wastewater and public acceptance. People were found to be more inclined towards reuse for purposes with minimal human contact such as landscaping and agriculture with opposition when it came to use for personal use. Moreover, the results showed a general lack of trust in governing institutions and authorities, which could explain perceived health risks and perceptions of risk resulting from system failure. Overall, the willingness to use treated wastewater was found to vary as a function of the “disgust factor,” religious beliefs, and perceptions of a high risk towards contracting waterborne diseases. The disgust towards reuse of treated wastewater was found to be a strong predictor affecting willingness to reuse whereby those who believed it is disgusting to reuse treated wastewater were found to be on average, three times less likely to reuse treated wastewater as compared to those who did not declare disgust. Similarly, a significant association was found between religious beliefs and respondents’ willingness to use treated wastewater. Interviewees who thought treated wastewater reuse is not religiously accepted were, on average, twice less likely to use treated wastewater as compared to those who did not believe that reuse contradicts with their religious beliefs. Additionally, people’s perceptions on associating the spread of water-borne diseases with reuse were found to be significant. Those who perceived that reusing treated wastewater would lead to diseases and affect the human health, were on average, twice less likely to accept reuse. Developing a comprehensive strategy that integrates increasing awareness and knowledge, setting policies related to water reuse, building public trust and communication channels, increasing public participation/engagement in decision making, and developing a sustainable management framework is thus crucial before any investments are made in reclaimed water-reuse projects.