2. Sources of pharmaceutical micropollutants in the aquatic environment

Pharmaceuticals are important and indispensable elements of modern life. They are used in humans and animals, in agriculture and in water culture. The presence of pharmaceuticals in the environment first attracted the attention of the scientific community and the public in the 1970s. However, until the 1990s, little has been done about the presence, behavior, and effects of pharmaceuticals in the environment. During this time, environmental pollutants such as heavy metals, polycyclic hydrocarbons, dioxins, furans, pesticides, and detergents have been extensively studied. Endocrine system drugs and lipid-lowering drugs have been on the rise since the 1990s. After this date, many studies have been done in the USA and Europe for hormones and other pharmaceuticals [8–10].

An important reason why so much care is taken with pharmaceutical products is that they have to produce a biological effect. They are made as stable as possible so that they can be stored for a long time and easily swallowed. The membranes are lipophilic enough to cross the membranes, and in order to reach the sites of action—especially those taken orally—drugs must be resistant to enzymes and must not hydrolyze at acidic pH values. They must be stable and have high mobility in liquid phase [11–13].

1. Introduction

42 Wastewater and Water Quality

effects [3].

these regulations [4].

present in the raw wastewater [1].

treatment strategies to improve biodegradation.

hormones and other pharmaceuticals [8–10].

Pharmaceutical wastewater is one of the most important gateways of emerging pollutants (such as synthetic hormones including corticosteroids) to enter water bodies. During the last years, numerous studies have documented the presence of many of these substances at the level of microgram or nanogram per liter in raw water (i.e., stream/source water), in wastewater effluents, and even in finished drinking waters [1, 2]. As a consequence, pharmaceuticals are entering in the trophic chain and causing adverse ecological and human health

Pharmaceuticals are not regulated at the moment in the EU, but the 2013 amendment of the Environmental Quality Standards Directive (2008/105/EC) contains a mechanism to collect high-quality data on concentration of compounds of environmental concern, the so-called watchlist. This list includes diclofenac, 17-beta-estradiol (E2), and 17-alpha-ethinylestradiol (EE2). For compounds on this list, it is likely that regulations will be developed in the future. This would mean that additional treatment of wastewater will be necessary to comply with

Membrane bioreactor (MBR) technique is a promising alternative to conventional treatment, [5, 6], and its usage is increasingly for municipal wastewater treatment and reuse, and great concerns have been raised to some emerging trace pollutants found in aquatic environment in the last decade, notably the pharmaceuticals [7]. In that sense, recently a pilot MBR was innovatively applied leading to removal efficiencies over 95% of the chemical oxygen demand (COD). Furthermore, other lab-scale MBR studies have been focused not only in the removal of the bulk organic matter but also in the elimination of the specific organic micropollutants

In this study, we present a comprehensive review of the studies carried out in the literature with MBR of micropollutant residues in different wastewaters, and it is expected that these pollutants, which are highly biologically active and difficult to biodegrade, shed light on

2. Sources of pharmaceutical micropollutants in the aquatic environment

Pharmaceuticals are important and indispensable elements of modern life. They are used in humans and animals, in agriculture and in water culture. The presence of pharmaceuticals in the environment first attracted the attention of the scientific community and the public in the 1970s. However, until the 1990s, little has been done about the presence, behavior, and effects of pharmaceuticals in the environment. During this time, environmental pollutants such as heavy metals, polycyclic hydrocarbons, dioxins, furans, pesticides, and detergents have been extensively studied. Endocrine system drugs and lipid-lowering drugs have been on the rise since the 1990s. After this date, many studies have been done in the USA and Europe for Because of these properties, active pharmaceutical ingredients/conversion products can be bioaccumulated and can cause effects in aquatic or terrestrial ecosystems.

The intake of drug active substances occurs in various ways. Starting from humans and animals, the active pharmaceutical ingredients reach the wastewater, soil, and groundwater and, if adequate treatment is not done, reach our drinking water. Pharmaceutical products can be roughly divided into two: medicinal products and veterinary drugs used by humans. Veterinary medicines are used in farm animal breeding and poultry production. Medicinal products used by humans reach sewage through urea and feces and from there to wastewater treatment plant. If xenobiotics are taken as an example, there are three possible behaviors of the substance: (i) the substance is completely mineralized to water and CO2 (e.g., aspirin). (ii) The substance is lipophilic and does not easily fragment. So, some of the material is kept in clay. (iii) The substance is metabolized to a more hydrophobic than lipophilic form but becomes resistant. It cannot be removed in the treatment plant, and it is thrown away with wastewater and mixed with the receiving waters. If the metabolites are still biologically active, they also affect the aquatic organisms in the environment. Possible materials in clay, if the mud is laid on the field, may affect microorganisms and the useful ones. Medicinal substances used to support growth of animals in the stables are mostly fertile. These substances can affect soil organisms. The hydrophilic materials in the sewage sludge, which are scattered in the mouth, reach the aquatic environment by infiltrating with rain [11–13].

Pharmaceutical substances used for animals in the field are thrown directly to the ground via urea and feces. High local concentration affects soil organisms. It is also possible that medicinal substances spread over the surface are mineralized to the ground or reach the groundwaters.

They are used in fish farms and are directly confused with the receiving waters because the best way to treat fish with antibiotics and other medicines is to use feed additives. Because most of the feed additives are not eaten by the fish, they fall from the cages and accumulate in the seabed. These substances can affect aquatic organisms. An unknown part of the medical goods sold for human use is thrown into the toilet as waste by people and reaches the treatment plant by interfering with the sewage system [14–17].

Micropollutants consist of a vast and expanding array of anthropogenic as well as natural substances. These include pharmaceuticals, personal care products, steroid hormones, industrial chemicals, pesticides, and many other emerging compounds. Micropollutants are commonly present in waters at trace concentrations, ranging from a few ng/L to several μg/L. The "low concentration" and diversity of micropollutants not only complicate the associated detection and analysis procedures but also create challenges for water and wastewater treatment processes [2].

Sources of micropollutants in the environment are diverse, and many of these originate from mass-produced materials and commodities. Table 1 summarizes the sources of the major categories of micropollutants in the aquatic environment.

they are designed to kill and inhibit the growth of microorganism; thus, they will hinder the activity of beneficial microbes in wastewater treatment plant (WWTP) operation and involved in their removal. Moreover, for constant exposure to antibiotics, microbial community stay in wastewater improves resistant mechanism more readily than the rest of another microbial world. The presence of numerous antibiotic compounds was identified in untreated wastewater in both aqueous and solid phases. Overall, occurrence and persistence of antibiotics in water bodies increase concern; almost 90% of antibiotics consumed by human body were

Efficient Removal Approach of Micropollutants in Wastewater Using Membrane Bioreactor

http://dx.doi.org/10.5772/intechopen.75183

45

Therapeutic hormones are the synthetic analog of animal or plant natural hormones, which affect the endocrine system and have impacts on human and animal health. The most frequently found hormones in the environment are estrogens. A synthetic estrogenic steroid is used as a birth control agent and in estrogen substitution therapies. Thus, estrogen and its metabolite become the abundant class of emerging pharmaceutical contaminants. The metabolite of 17bethinyl estradiol and estrone (E1) is one of the most powerful EDCs creating impacts in aquatic organisms. Their presence in the river environment causes adverse reproductive and developmental effect in nontargeted organisms [20]. Several studies confirmed that the presence of estrogen in both influent and effluent of municipal wastewater treatment plants at a concentra-

Analgesic is the widely used drug for pain relaxation and to treat fever. Drugs belonging to the class of analgesics such as naproxen acetaminophen, ibuprofen, diclofenac, and meprobamate were treated as significant environment pollutants due to their persistence in the aquatic environment [22]. Almost, 15% of ibuprofen was excreted after administration and 26% as its metabolite. The metabolite of ibuprofen is more toxic to aquatic organisms than parental compound [23]. The presence of ibuprofen, diclofenac, naproxen, gemfibrozil, and hydrochlorothiazide in the river shows a concentration range from 2 to 18 ng/L. The occurrence of these xenobiotic compounds in natural water bodies represents a significant concern for human health as little information is available on the effect of long-term ingestion of these compounds through drinking water [19].

Pharmaceutical compounds pass on a set of biochemical transformation in human and animal body and form polar, hydrophilic, and biologically active metabolites, which are discharged through urine and feces and enter WWTP. These active metabolites are accumulated in tissues of aquatic organisms. They have the potential to bind covalently to their cellular protein and may evoke an immune response or exert toxic effects [25]. These metabolites are reported to be 50% more toxic than their parental compounds. The poorly metabolized parental pharmaceutical substances undergo a transformation and affect the action of microbial community present in

tion ranges from 5 to 188 ng/L and between 0.3 and 12.6 ng/L, respectively [19, 21].

discharged via urine and feces [19].

2.2. Therapeutic hormones

2.3. Analgesic pharmaceuticals

2.4. By-product and metabolites

Pharmaceuticals are thoroughly used to cure the diseases in humans and as veterinary drugs. These biologically active chemicals are treated as emerging contaminant due to their persistence and potential harmful impact on the aquatic ecosystem.

These refractory emerging contaminants (RECs) (analgesics, anti-inflammatories, antiepileptics, and antibiotics) fall into the class of endocrine-disrupting compounds, which continually enters into the aquatic environment in small concentration.

They remain active even in low concentrations and deteriorate water quality and have an adverse impact on the ecosystem and human health. The most common and persistent pharmaceutical products in the aquatic environment are summarized below.
