The present invention discloses a filtration system for treating untreated liquid such as greywater or any liquid that is contaminated with impurity and is required to be treated before use. The filtration system is a gravity fed liquid treatment system and includes components such as a top liquid tank for holding untreated liquid and a bottom liquid tank for holding treated liquid. The filtration system further includes one or more filtration media containers and filtration columns. Each filtration column is a composition of the stacked filtration media containers. The filtration system may be used for cleaning the contaminated water or keeping clear the surface of open water from oil or the like floating materials by separating or removing these materials from the water. The filtration system may include portable or detachable small-scale multistage treatment devices and may be implemented using household-type filters for producing potable filtration system.

Method and apparatus for filtration of polluted liquid in a single upright filtration tank, comprising feeding of fresh filter material via a fresh filter material inlet in a lower part of the filtration tank, feeding of polluted liquid via a liquid inlet in an upper part of the filtration tank, mixing of the filter material and the polluted liquid in the single upright filtration tank to filter the polluted liquid by conveying filter material from the lower part of the filtration tank to the upper part of the filtration tank, and discharge of used filter material through an upper used filter material outlet in the upper part of the filtration tank, and discharge of clean liquid from the filtration tank through a lower clean liquid outlet in the lower part of the filtration tank.

A water filtration and disinfection device comprises a water basin having an inlet for receiving water from a source. A sidestream treatment device is provided for treating water from the water basin, and the sidestream treatment device comprises a plurality of filtration or disinfection mechanisms for acting on water within the sidestream treatment device. A feed conduit extends between the water basin and the sidestream treatment device for feeding water from the water basin to the sidestream and a return conduit extends from the sidestream treatment device to the water basin for returning at least a part of the water to the water basin.

Systems and methods for treating wastewater are disclosed. Zero valent iron media may be used in a moving packed bed reactor. A media recovery system may return media to the reactor.