A waste water treatment system including primary settling tanks. The waste water treatment system includes a trough which causes waste water to flow in a direction parallel to a bar screen placed in the trough with the base of the bar screen being at a lower elevation than the trough weir. Each primary settling tank has a fine screen box for screening waste water. Each primary settling tank has a scum and floatables trough for collecting scum and floatables which pass through or over a top edge of the bar screen. The scum and floatables troughs are in fluid communication with one another. When a scum valve is open, scum, floatables and waste water in the scum and floatables trough flow from the scum and floatables trough of the first primary setting tank to the scum and floatables trough of the second primary settling tank and into a collection container.