Newsletter and Technical Publications
<International Source Book On Environmentally Sound Technologies
for Wastewater and Stormwater Management>
A sensitive area must be identified if the body of water falls into one of the following groups:
- Natural fresh-water lakes, other fresh-water
bodies, estuaries and costal waters which are found to be eutrophic or may become eutrophic.
- Surface fresh-waster intended for the abstraction of drinking water which contain more the concentration
of nitrate laid down in the Councilīs nitrate Directive 75/440.
- Any other area where further treatment is necessary to fulfill the purpose of the directive.
A less sensitive area is:
- A marine body of water if the discharge does not
adversely affect the environment provided that there is no risk that the
discharged load may be transferred to adjacent areas.
- Open bays, estuaries and other costal waters
with a good water exchange and not subject to eutrophication or oxygen
depletion or not likely to be so.
Figure 6.8 shows the sensitive and the less
sensitive areas which have been identified by the Member States as of 1998, and
Tables 6.13 and 6.14, respectively, indicate the removal rates for BOD5, nitrogen and phosphorous.
Figure 6.8: Sensitive and less sensitive areas
Table 6.13: Requirements for discharges into normal areas
(values for concentration or for percentage reduction)
|Reference method of measurement
|BOD5, without nitrification
40 in high mountain
|Addition on a
60 in high mountain regions and 2000 to 10000 pe
90 in high mountain regions and 2000 to 10000 pe
|Filtering through 0,45 um filter membrane
Centrifuging at least 5 minutes at mean acceleration of 2800 to 3200
Table 6.14: Additional
requirements for discharges into sensitive areas (one or both parameters may be
applied depending on the local situation)
|Reference method of measurement
|2 mg/l P (10000 to|
1 mg/l P (more than
||15 mg/l N (10000 to|
10 mg/l N (more than
|*The sum of total Kjeldahl-nitrogen.
Source: EEC, 1991
The European Commission is responsible to monitor and report upon the
implementation of Directive 91/271. A first report was due in June 1994 but has
been published in 1998 only due to delays in national reporting (CEE 1998). The
report includes information on implementation as of July 1998, viz. coverage
attained and projections concerning with wastewater collection systems and
treatment plants, meeting the obligation concerning industrial waste discharge
respectively via urban collection systems and treatment plants and by direct
discharge into receiving waters, quantity and methods of disposal of sewage
sludge, and projected investment needed to meet the requirement both with
respect to collection systems and treatment plants up to the year 2005.
Additional up-to-date information is contained
in the report on Environment in the European Union at the turn of the Century
(EEA 1999). The report states that after implementation of the Directive, the population
not connected to sewers will be halved compared to the present situation;
around 30 million persons or 5% of the total waste water will not be connected
to sewers (see Table 6.15 and Figure 6.9). It has been assumed that no
untreated wastewater will be discharged. The majority will either be treated by
secondary treatment or secondary treatment plus nutrient removal. In Spain,
Italy, Portugal and the United Kingdom the majority of wastewater will receive
secondary treatment, while in Germany, France, Greece, Luxembourg, The
Netherlands, and Finland the wastewater will also be treated in plants with
nutrient removal. In the countries with no specific information on treatment
after implementation of the UWWT Directive more than 80% in Sweden and Denmark
today receive treatment with nutrient removal and only small changes due to the
Directive can be foreseen. In Austria it is assumed that secondary treatment
plus nutrient removal will be provided whereas in Belgium and Ireland there
will be at least secondary treatment.
Table 6.15: Wastewater treatment of the combined load from
household and indirect industrial discharges in EU10* countries (in pe as of end 1994)
|* EU10 countries include Germany (DE), Spain
(ES), France (FR), Greece (GR), Italy (IT), Luxembourg (LU), Netherlands
(NL), Portugal (OT), Finland (FI), and the UK (UK). Source: EEA, 1999