33For large surfaces of over 1,500 square meters and more,
ride-on sweepers equipped with large-volume containers
and hydraulic high dumps are used.
If stubborn dirt such as mosses, lichens, bird droppings or chewing
gum and food waste must also be removed, cold-water high
cleaners are normally used. In this case, care should be taken that
sufficient water is available to dissolve the dirt effortlessly
wash it away (starting at 600 liters per hour and more). Hot-water
high-pressure cleaners dissolve greasy dirt more easily. In addition,
the cleaned area dries faster. For preventive cleaning, a dirt
pick-up system adapted to its surroundings
is also important. Large
mats are laid both inside and outside of doors; these catch dirt from
shoes and bind it so that it isn’t carried further (at least four steps
long). In the case of external
mats, a slightly more abrasive bristle
surface is recommended
to reach dirt even on shoes with deep profiles.
In inside areas, the bristles can be softer and finer to pick up
the last bits of residue and moisture. Dirty mats must also be regularly
replaced by clean ones, or they must be thoroughly cleaned.
Gentle weed removal
Effectively fighting weeds is a great challenge. Although there are
chemical products for this, they tend to pollute the environment.
Since early 2015, their use in public spaces is very limited.
weeping or solutions with hot water as well as mechanical
brooms are alternatives. Prevention is the best medicine for stopping
weeds. Regular sweeping is the only antidote for combating
weeds that are trying to grow in the so-called bitumen layer
between the asphalt and curb of roads, for example. Sweeping
removes the dust and dirt that mixes with rainwater to offer a good
breeding ground for weeds; it also gets rid of their seeds.
In places where higher weed growth is not particularly disturbing,
removal can begin later in the year. In this case, the most effective
method is hot water. The water is heated to around 99 degrees
Celsius and reaches the plant roots – in contrast to hot air, which
only reaches the plant – with a temperature of 92 degrees Celsius.
When confronted by temperatures of over 65 degrees Celsius,
plant roots build a surplus of ascorbic acid and send back to the
leaves, thus destroying the plant. After the hot water treatment,
the weeds look like blanched spinach; two to three days later, they
This method can also be used on water-bound paths such as gravel
or on red clay courts where sweepers cannot be used. N
Gerd Heidrich, Kärcher | Alexandra Lachner, freelance journalist |
STEAMBEAST New technology for the fast,
gentle and efficient cleaning of
highly soiled and sensitive
ZAUGG AG EGGIWIL, Tel. +41 (0)34 491 81 11, email@example.com
GLOBAL CLEANING | ISSUE 2018 47