The wastewater treatment systems have a plurality of treatment modules between the inlet and the outlet, each for treating water with a selected process. Influent is directed to a covered anaerobic reactor, and then to an attached growth pretreatment filter that is at least intermittently exposed to atmospheric oxygen. Following the filter is a hydroponic reactor followed by a vertical-flow wetland. A second embodiment includes, following the filter, a tidal vertical-flow wetland and a pump for recycling water exiting the wetland upstream of the filter.