Projection and construction of WATER PURIFICATION MARSH
Presentation
of the method
Bergum
Water
purification marsh is a circuit cleaning alternative. By constructing
artificial wetlands to favor biological production nutrients are
transferred to biomass in food chains dispersed to the surroundings.
Frogs
The
organisms making the reduction of nutrients possible are microscopic
plants and animals giving a swarming wetland with high biological
diversity.
Summer picture, Svenseröd
A
water purification marsh is established on a slightly sloping land
and adjusts to the character of the place. Every marsh is unique
so special knowledge is needed for planning. The principle is a
number of shallow ponds placed after each other where each pond
represents an ecosystem. The water purification marsh can be used
for cleaning of wastewater from one or many houses, for cleaning
water from land runoff and agricultural runoff and as an extra cleaning
step after a sewage treatment plant. The construction cost is low
but a certain care to fulfill the function in the marsh is needed.
The attention implies that leakage is avoided, no shadowing vegetation
is allowed, the edges shall be trimmed. Specially before wintertime
it is important to take away shadowing vegetation.
Winter
picture, Svenseröd
In
the water purification marsh there is a more effective reduction
of nutrients than with traditional methods, with over 90 % cleaning
of both nitrogen and phosphorous most of the year. In summertime
and during dry periods when there is no outflow the cleaning is
100 %. The water purification marsh shall be constructed in a way
that ice do not overflow in the surroundings in extreme winter situations
when the whole marsh is totally frozen and ice is established. The
nutrients are stored in the ice and as soon as it melts the biological
production starts with the same high nutrient reduction as in the
summer. The reduction of bacteria is at the same level as in the
now often used methods for cleaning wastewater with different kinds
of infiltration.
