Evaluation of Constructed Wetland as Secondary Wastewater Treatment, Source for Tertiary Wastewater Treatment, and Reuse System

This paper describes an investigation into the treatment effectiveness and feasibility of constructed wetland (CW) system as a secondary wastewater treatment system, as an economic agricultural producer, and as a pretreatment phase for an ultrafitration/reverse osmosis UF/RO tertiary treatment plant. The treatment system consists of one vertical-flow infiltration CW cell (150 m² in surface area, 112.5 m³ in volume) and two settling basins (one before and one after the CW); gravel, coastal sand, and almond shells were used as CW media. The CW was vegetated with various plants including spineless cactus. Samples were analyzed for total plate count, turbidity, total nitrogen, total phosphorus, total suspended solids, biochemical oxygen demand, chemical oxygen demand, temperature, conductivity, and pH. The CW operation indicated a significant reduction in influent water quality and proved to be of suitable for smooth operation of the UF/RO pilot plant. High biomass growth was observed on the spineless cactus and banana and little or negative growth was obtained on other planted crops.