Evaluation of wetland system with macrophyte Sagittaria montevidensis Cham. & Schltdl. for polluted urban water treatment

Abstract

This work aimed to evaluate a bed cultivated water treatment system, designed for the treatment of water polluted by urban wastewater, such as Ribeirão dos Müller (Curitiba – PR). The system used the macrophyte Sagittaria montevidensis for both organic matter and coliforms removal. An initial evaluation of the water from the Ribeirão dos Müller, who currently presents similar characteristics to domestic wastewater, with average COD equal 250.82 ±186.48 mg.L-1, OD of 1.14± 0.94 mg.L-1 and average number of 16.106 for total coli forms (CT) and 10.106 for thermo-tolerant coli forms (CF), with Escherichia coli. The system was monitored and operated during two different periods of time. The main components of the system are water intake, transfer pump, distribution reservoir and the vegetated (cultivated) bed. The filter, that constitutes the cultivated bed, was composed by layers of 5-crushed stone, 2-crushed stone, porcelain and medium sand, and was also used to support the plants. The system hydraulic detention time (HDT) resulted about 10 hours for a 3.600 L.d-1 flow. The pH values ranged from 5.8 to 8.9 with stability for alkalinity and volatile acids. The average COD removal efficiency was 63.76 ± 14.30% for the first monitoring period and 62.93 ± 15.57% for the second one. In short, the results indicated for the polluted urban water treatment for presenting characteristics of a natural environment, beyond being considered a system with low cost of implantation and operation.