This is especially important if treatment is by slow sand filters.

This removal showed to be comparable to that of the slow sand filter.

Slow sand filters, due to their simple design, may be created diy.

Slow sand filters do not require chemicals or electricity to operate.

The purification system was a slow sand filter design that became obsolete by the late 20th century.

Slow sand filters require relatively low turbidity levels to operate efficiently.

Due to the low filtration rate, slow sand filters require extensive land area for a large municipal system.

Requires greater maintenance than a slow sand filter.

It soon became apparent that slow sand filters could remove typhoid germs.

The system was developed from the slow sand filter, a technology used for drinking water purification for almost 200 years.

Slow sand filters have a number of unique qualities:

Slow sand filters can produce very high quality water free from pathogens, taste and odour without the need for chemical aids.

The Paisley filter began operation in 1804 and was an early type of slow sand filter.

The rapid filters and the slow sand filters engaged in competition as to which technology was superior.

The water produced from a well-managed slow sand filter can be of exceptionally good quality with 90-99% bacterial reduction.

Slow sand filters or carbon filters are used to provide a place on which these micro-organisms grow.

In La Fortuna, the group utilized a slow sand filter in its system.

Unlike other filtration methods, slow sand filters use biological processes to clean the water, and are non-pressurized systems.

Slow sand filters may be used where there is sufficient land and space, as the water must be passed very slowly through the filters.

Slow sand filters rely on biofilm development in the same way to filter surface water from lake, spring or river sources for drinking purposes.

Slow sand filters are used in water purification for treating raw water to produce a potable product.

The plant was the first continuously operated slow sand filter plant in the U.S.

Throughout the 1800s, hundreds of slow sand filters were constructed in the UK and on the European continent.

In water purification works, the hypogeal (or Schmutzdecke) layer is a biological film just below the surface of slow sand filters.

Its products include slow sand filters, iron-removing filters, and roughing filters.