2.2. Therapeutic hormones

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

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 persis-

These refractory emerging contaminants (RECs) (analgesics, anti-inflammatories, antiepileptics, and antibiotics) fall into the class of endocrine-disrupting compounds, which continually

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 phar-

In recent years, global consumption and the use of antibiotics increase to >30% [18]. Antibiotics are generally treated as pseudo-persistent compound because of its continuous introduction in environment. The existence and release of antibiotics are inclined to be of specific concern since

Domestic wastewater (from

Domestic wastewater (from bathing, shaving, spraying,

Runoff from CAFOs and

Industrial wastewater (from industrial cleaning discharges) Domestic wastewater (by leaching

out of the material) Domestic wastewater (from improper cleaning, runoff from gardens, lawns, roadways, etc.)

Agricultural runoff

bathing, laundry, dishwashing, etc.)

CAFOs and

Sources that are not exclusive to individual categories

industrial wastewater (from product manufacturing

Landfill leachate (from improper disposal of used, defective, or expired items)

include

discharges)

Category Important subclasses Major sources Nonexclusive

Estrogens Domestic wastewater (from

excretion) Hospital effluents Runoff from <sup>b</sup>

aquaculture

swimming, etc.)

excretion)

aquaculture

categories of micropollutants in the aquatic environment.

tence and potential harmful impact on the aquatic ecosystem.

enters into the aquatic environment in small concentration.

NSAIDs, lipid regulator, anticonvulsants, antibiotics, β-blockers, and stimulants

Fragrances, disinfectants, UV filters, and insect repellents

Plasticizers, fire retardants Insecticides, herbicides, and

Table 1. Sources of micropollutants in the aquatic environment.

fungicides

NSAIDs, Nonsteroidal anti-inflammatory drugs.

CAFOs, concentrated animal feeding operations.

Surfactants Nonionic surfactants Domestic wastewater (from

2.1. Antibiotics

44 Wastewater and Water Quality

Pharmaceuticals <sup>a</sup>

Personal care products

Steroid hormones

Industrial chemicals Pesticides

a

b

maceutical products in the aquatic environment are summarized below.

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

## 2.3. Analgesic pharmaceuticals

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].

### 2.4. By-product and metabolites

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

the WWTP. These metabolites are persistent due to their weaker sorption potential and high mobility and, thus, detected in environmental samples [26].

Literature reported that the concentration of the metabolite in influent and effluent of WWTP is often higher than their parental compounds, and their fate depends on the environmental conditions such as salinity, temperature, pH, and microbial diversity [19, 27].

Many studies on removal of pharmaceutical compounds from wastewater have been conducted, and many treatment technologies of hospital wastewater treatment have been developed.

Treatment of pharmaceutical residues using MBR processes was discussed in the following sections.

> Since submerged MBRs operate at lower operating fluxes, they have greater hydraulic efficiency due to greater permeability. Working with low flux is important in submerged MBR because this application minimizes membrane contamination or plugging. Membrane blockage is one of the major disadvantages of MBRs and requires cleaning mechanisms that increase cost and make operation difficult. While submerged MBRs require lower pumping costs than external MBRs, they require more aeration. The reason is that the aeration is the main method to prevent membrane clogging. In addition, low flux studies in submerged MBRs require more membrane surface area (and hence greater initial investment cost) when based on constant permeate flux production. Despite these disadvantages, however, the selected and implemented configuration for medium- and large-scale municipal wastewater

> Figure 1. Configuration of MBR systems: (a) submerged (immersed) MBR and (b) sidestream (external) MBR configura-

Efficient Removal Approach of Micropollutants in Wastewater Using Membrane Bioreactor

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

47

By the year 1990s, this existing accumulation has been rapidly increased by the MBR applications which are made as academic and field studies. MBR producers are Kubota from Japan,

Rayon

Polymer PVDF PE PVDF PE PVDF Filtration type UF MF MF MF MF Module Hollow fiber Hollow fiber Hollow fiber Flat sheet Flat sheet Hydrophilic Yes Yes Yes Yes Yes Outside diameter (mm) 1.95 — 1.00 490 (width) 460 (width) Inside diameter (mm) 0.92 — 0.65 1000 (height) 1010 (height) Fiber length (mm) 1650 663.5 1010 6 (thickness) 7 (thickness)

Pore size (μm) 0.04 0.4 0.2 0.4 0.2

) 23/module 105/module 20/module 0.8/panel 0.7/panel

h) 25.5 10.3–16.7 15 25.5 20–30

Tianjin Motimo Kubota<sup>b</sup> Shanghai

Zizheng

Zenon from Canada, Mitsubishi Rayon, and US Filtration [36, 39, 40] (Table 2).

treatment is the internal submerged MBR [38].

Items Zenon Mitsubishi

tion (adapted from [32, 37]).

(1) Membrane module properties

Surface area (m<sup>2</sup>

Normal flux (L/(m<sup>2</sup>
