Drinking Water in Germany: A Case Study of High Quality Drinking Water - Global Drinking Water Management and Conservation - page 259

12.5 Micropollutants in Three Countries

As mentioned above, the presence of pharmaceuticals and personal care products
(PPCPs) in wastewater has become a global issue. From 1996 to 1998, a com-
prehensive study in Germany was undertaken by Ternes ( 1998 , 2000 ). He detected
32 of 55 pharmaceuticals, 4 of 6 hormones, 5 of 9 metabolites, and 5 of 6 biocides
in the out the

receiving water bodies contained concentrations of beta-blockers and antiepileptic
agents in excess of 1

ow of 49 wastewater treatment plants. He further found that “

g/L ” (Ternes 2000 ). However, Ternes et al. ( 2004 ) pointed

μ

these comprehensive monitoring studies 3 and the many subsequent individual
studies (Heberer 2002 ; McArdell et al. 2003 ; Huang; Sedlak 2001 , Metcalfe et al.
2003 ; Boxall et al. 2004 ; Jones et al. 2001 ) included only a small subset (less than
15 percent) of the pharmaceuticals and personal care products (PPCPs) predicted to
potentially enter the environment.

out “

” They further noted that “ studies were launched

to investigate the effects of individual PPCPs on biota (Huggett et al. 2002 ; Ferrari

et al. 2003 ; Wollenberger et al. 2000 ). However, because of incomplete data,
researchers still lack a complete understanding of the environmental effects of most
PPCPs. Thus, no one knows whether the relatively low environmental concentra-
tions of PPCPs produce adverse effects on aquatic and terrestrial biota or whether
the toxicity of complex mixtures might be totally different from that of individual
compounds (Altenburger et al. 2000 ). Therefore, Ternes et al. ( 2004 ) recommended
that

”

for precautionary reasons, we can be proactive and reduce the inputs of
micropollutants to the environment as completely as possible through the intro-
duction of cost-effective control options

“

.
One very cost-effective way of neutralizing PPCPs is through a process of
biological degradation, which usually requires a few days of

”

of the
sludge. The process of biological degradation of the contaminants can be described
as follows (Ternes et al. 2004). In wastewater, PPCPs occur primarily at concen-
trations of less than 10 − 4 g/L. At these levels, biological transformation or degra-
dation of the trace pollutants occurs only if a primary substrate is available so that
the bacteria can grow on it. In this way, cometabolism occurs, in which case the
bacteria break down or partially convert the trace pollutant. Alternatively, mixed-
substrate growth takes place and the bacteria use the trace pollutant as a carbon and
energy source and may mineralize it totally. Thus biological degradation is of
crucial importance and adequate time must be allowed for the degradation to take
place.
Moreover, in order to comply with the requirements of the EU Urban Waste
Water Treatment Directive 4 for discharges of wastewater treatment plants to water
bodies such as the coastal waters of the North Sea, Ternes et al. ( 2004 ) proposed a
time period of 12 to 15 days of retention time for adequate degradation of pollutants

“ retention time ”

3 These studies were carried out in the UK, Canada, and USA.
4 For example, as we referred in Sect. 12.2.1, the EU Urban Waste Water Treatment Directive
requires a reduction of 75 percent for nitrogen; Germany exceeds this reduction requirement.