A wastewater treatment system includes a first lagoon having an inlet for receiving wastewater to be treated and a first vertical flow marsh cell having a bottom outlet. Water can be transported from the first lagoon to the first marsh cell. A second lagoon has an inlet for receiving water from the first marsh cell outlet and a second vertical flow marsh cell having a bottom outlet. Water can be transported from the second lagoon to the second marsh cell. At least a portion of the water exiting the second marsh cell outlet can be recycled to the first lagoon. The first and the second lagoon are adapted to function essentially aerobically and to contain plants having roots positioned to contact water flowing thereinto. The first and the second marsh cell are adapted to contain plants having roots positioned to contact water flowing thereinto.