Page 161 - Materials Chemistry, Second Edition

142 Life Cycle Assessment of Wastewater Treatment

of sewage sludge from WWTPs, which is used as a soil improver and known as
biosolids. Currently, no legislation exists regarding the limits of pharmaceuticals
and PhACs in biosolids. They may contain high concentrations of PhACs, which
contaminate the soil and ground water (Rodríguez-Rodríguez et al., 2011; Tilman et
al., 2002; Kinney et al., 2006). The resultant POPs, which are persistent in nature,
can remain in the soil, even long after their use, and can enter the human food cycle
directly or by percolation to the ground-water table (Gavrilescu, 2005). In addition,
large amounts of pharmaceuticals annually are used in livestock farms and fisher-
ies as well as shrimp hatcheries (Uddin and Kader, 2006). The release of veterinary
pharmaceuticals, especially antibiotics, which are used to prevent disease in ani-
mals, treat infections, and promote animal growth, is another main contributor of
pharmaceuticals to the environment (Sim et al., 2011; Kim et al., 2013).
After pharmaceutical intake, the active compounds can be excreted by animals
into water bodies as the parent compound, conjugates, or metabolites, which have
become a potential and emerging environmental issue (Marco-Urrea et al., 2010c;
Langford and Thomas, 2009). It is claimed that up to 90% of an administered dose of
antibiotics is excreted through urine and feces (Drillia, Stamatelatou, and Lyberatos,
2005). It is believed that the PhACs are spread into the environment mostly via
human or animal consumption and subsequent excretion in the feces and urine, and
by direct disposal of expired or unused pharmaceuticals by patients and custom-
ers (Halling-Sørensen et al., 1998; Cruz-Morató et al., 2013). Mass flow analysis of
PhACs has shown that the concentrations of these compounds in the environment are
in the range of nanograms to micrograms per liter; therefore, acute toxic effects are
unlikely (Ikehata et al., 2006). However, although little is known about the chronic
environmental toxic effect of PhACs, the potential risk of chronic effects cannot be
neglected (Rodarte-Morales et al., 2011; Crane et al., 2006; Boxall et al., 2003).
Hospital effluent can be considered as one of the main contributors to the pres-
ence of PhACs in the influent of WWTPs. The concentration of PhACs in hospi-
tal effluent is considerably higher (up to milligrams per liter) compared with their
concentrations in the WWTP influents (Verlicchi et al., 2012a). Currently, hospital
effluents are not treated separately before being discharged into public sewer net-
works to be treated along with urban wastewater; therefore, some researchers believe
that hospital wastewater is the main contributor to PhAC concentrations in WWTP
influent (Verlicchi et al., 2012b; Langford and Thomas, 2009). Nevertheless, some
other authors do not concur; they believe that the amount of PhACs contributed by
hospital effluent is negligible compared with the large inflow of PhACs introduced
by municipal wastewater (Le Corre et al., 2012). Compared with the effluent from
hospitals, effluent from pharmaceutical and industrial manufacturers would prob-
ably have fewer PhAC compounds, but in more significant concentrations, which
could potentially overload the aquatic environment. Therefore, it is likely that hos-
pital effluent and pharmaceutical manufacturers’ effluent contribute to some extent
to the PhAC load in WWTP influent (Langford and Thomas, 2009). Pharmaceutical
production facilities are another source of PhACs in the environment. Despite the
strict environmental standards and a different set of regulations for the manufactur-
−1
ers’ effluents, Larsson et al. reported concentrations above 1 µg L for 21 phar-
maceutical compounds out of 59 initially screened for in the wastewater effluent