km
500
400
300
200
100 J---'
- - 0 +---,-----,-----.-----.----.-----,----r--1945
1950 1955
1960 1965 1970
1975 1979
Fig. 9. In 1945 the homes of only half of the 80,000 Bremerhaven inhabitants were connected
via drainage channels with the Weser River, the other half used septic tanks or other techniques
of sewage disposal which are now regarded as health risks. From 1950 to 1979 400 km of drainage
channels have been added to the original about 100 km, and in 1979 the homes of 134,000
Bremerhaven inhabitants (97% of 137,000) were connected with the Weser River. This explains
the poor water quality in the Weser. Improvement may be expected when the sewage treatment
plant now under construction starts to operate in 1982. The figure represents the length of drainage channels in Bremerhaven, Germany. (From newspaper information)
Since then, numerous treatment plants have been put into operation and conditions
have improved.
Originally, in the Federal Republic of Germany no more than 20% of the samples
were permitted to have Escherichia coli counts higher than 10,000 per 100 ml if a
coastal water area was to pass the normal swimming standard. In 1975 the European
Community issued guidelines for the quality of bathing waters which have been binding for member countries since 1978 (see Chap. 10). According to these, at least 95%
of all analyzed samples must contain less than 2,000 fecal-coliform bacteria, and less
than 10,000 total-coliform bacteria per 100 mI. Amounts under 100 fecal-coliform
germs per 100 ml in at least 80% of the samples are desirable. The samples should
normally be taken every two weeks during the swimming season.
These rules apply to Great Britain as well. The British are calculating 100 million £
for the construction of new treatment plants which they will need in order to come
up to the European water standards for swimming. This has given rise to the question
whether funds of this magnitude might not be better applied more effectively in
other areas of public health (Moore 1977). By the way, chlorination of untreated
domestic sewage reduces Escherichia coli in coastal areas to European Community
swimming standard at minimal costs compared with waste water treatment plants
(Jenkins 1981).
2.3 Eutrophication
When domestic effluents are biodegraded by bacteria, not only carbon dioxide and
water, but also nitrogen and phosphorus are released as inorganic compounds which
were originally contained in the protein component of plants and animals. Nitrates,
phosphates, and other salts are nutrients essential for the growth of plants. The circu16
500
400
300
200
100 J---'
- - 0 +---,-----,-----.-----.----.-----,----r--1945
1950 1955
1960 1965 1970
1975 1979
Fig. 9. In 1945 the homes of only half of the 80,000 Bremerhaven inhabitants were connected
via drainage channels with the Weser River, the other half used septic tanks or other techniques
of sewage disposal which are now regarded as health risks. From 1950 to 1979 400 km of drainage
channels have been added to the original about 100 km, and in 1979 the homes of 134,000
Bremerhaven inhabitants (97% of 137,000) were connected with the Weser River. This explains
the poor water quality in the Weser. Improvement may be expected when the sewage treatment
plant now under construction starts to operate in 1982. The figure represents the length of drainage channels in Bremerhaven, Germany. (From newspaper information)
Since then, numerous treatment plants have been put into operation and conditions
have improved.
Originally, in the Federal Republic of Germany no more than 20% of the samples
were permitted to have Escherichia coli counts higher than 10,000 per 100 ml if a
coastal water area was to pass the normal swimming standard. In 1975 the European
Community issued guidelines for the quality of bathing waters which have been binding for member countries since 1978 (see Chap. 10). According to these, at least 95%
of all analyzed samples must contain less than 2,000 fecal-coliform bacteria, and less
than 10,000 total-coliform bacteria per 100 mI. Amounts under 100 fecal-coliform
germs per 100 ml in at least 80% of the samples are desirable. The samples should
normally be taken every two weeks during the swimming season.
These rules apply to Great Britain as well. The British are calculating 100 million £
for the construction of new treatment plants which they will need in order to come
up to the European water standards for swimming. This has given rise to the question
whether funds of this magnitude might not be better applied more effectively in
other areas of public health (Moore 1977). By the way, chlorination of untreated
domestic sewage reduces Escherichia coli in coastal areas to European Community
swimming standard at minimal costs compared with waste water treatment plants
(Jenkins 1981).
2.3 Eutrophication
When domestic effluents are biodegraded by bacteria, not only carbon dioxide and
water, but also nitrogen and phosphorus are released as inorganic compounds which
were originally contained in the protein component of plants and animals. Nitrates,
phosphates, and other salts are nutrients essential for the growth of plants. The circu16