A method of filtering water with a frame-type disc filter comprising: directing the water to be filtered into a water holding tank disposed adjacent an inlet end of a rotating drum where the water holding tank and the rotating drum form an integral part of the frame-type disc filter; directing the water to be treated from the water holding tank into the drum and through openings in the drum into a series of disc-shaped filter members mounted on the drum where the disc-shaped filter members include filter media secured on opposite sides of the disc-shaped filter members; causing the water to be filtered to pass through the filter media, producing filtrate; receiving and supporting said frame-type disc filter in an underlying support structure that includes an integral filtrate basin and a separate and integral effluent channel formed in the underlying support structure; collecting the filtrate produced by the frame-type disc filter in the underlying filtrate basin formed in the support structure; overflowing the filtrate from the basin in the support structure into the effluent channel extending adjacent the filtrate basin in the support structure; backwashing the filter media by pumping filtrate from the basin formed in the support structure to a series of nozzles disposed adjacent the filter media and spraying the filter media with the filtrate; diverting at least a portion of the water to be treated from the drum and from the disc-shaped filter members to form bypass water: directing the bypass water from the water holding tank to a bypass water collector which receives and holds bypass water and forms an integral part of the frame-type disc filter; directing the bypass water from the bypass water collector into the effluent channel formed in the support structure; mixing the bypass water with the filtrate in the effluent channel formed in the support structure; and discharging the mixture of bypass water and filtrate from the effluent channel formed in the support structure that underlies the frame-type disc filter. directing the water to be filtered into a water holding tank disposed adjacent an inlet end of a rotating drum where the water holding tank and the rotating drum form an integral part of the frame-type disc filter; directing the water to be treated from the water holding tank into the drum and through openings in the drum into a series of disc-shaped filter members mounted on the drum where the disc-shaped filter members include filter media secured on opposite sides of the disc-shaped filter members; causing the water to be filtered to pass through the filter media, producing filtrate; receiving and supporting said frame-type disc filter in an underlying support structure that includes an integral filtrate basin and a separate and integral effluent channel formed in the underlying support structure; collecting the filtrate produced by the frame-type disc filter in the underlying filtrate basin formed in the support structure; overflowing the filtrate from the basin in the support structure into the effluent channel extending adjacent the filtrate basin in the support structure; backwashing the filter media by pumping filtrate from the basin formed in the support structure to a series of nozzles disposed adjacent the filter media and spraying the filter media with the filtrate; diverting at least a portion of the water to be treated from the drum and from the disc-shaped filter members to form bypass water: directing the bypass water from the water holding tank to a bypass water collector which receives and holds bypass water and forms an integral part of the frame-type disc filter; directing the bypass water from the bypass water collector into the effluent channel formed in the support structure; mixing the bypass water with the filtrate in the effluent channel formed in the support structure; and discharging the mixture of bypass water and filtrate from the effluent channel formed in the support structure that underlies the frame-type disc filter.