Electricity-free water purification installation with a membrane filter and a system of automatic backwashing of the filter

An electricity-free water treatment plant, comprising:

• a membrane filter;
• and
• a supply pump configured to be operated physically to extract water to be treated from a water source, and to push the water source with a pressure from a water entrance through the membrane filter to an outlet to produce filtrate, in a filtering process;
• a rinsing water container, comprising a counter pressure generator;
• a non-electric secondary pump configured to divert, during the filtering process, a part of the filtrate through a one-way valve into the rinsing water container;
• and
• a pressure limiting seal configured to be opened and closed, which seal is not electronically controlled, the seal sealing off the rinsing water container at a certain pressure from a feedback to the membrane filter, wherein the seal is configured to be non-electronically opened by overpressure, to substantially simultaneously interrupt the inflow of filtrate from the membrane filter, to close the drain to the outlet, and to open a drain on the wastewater entrance of the membrane filter, thereby allowing rinsing water from the rinsing water container to be discharged after backwashing through the membrane filter.