Grey water treatment with phytodepuration experimental plant. Test of several plants species.

Abstract

Constructed wetlands are wastewater treatment. The depuration process done is called phytodepuration, which consists on the reduction or elimination of contaminants of the waste water, where the plants of the systems participated on it. A phytodepuration pilot plant has been designed and constructed, and it consists in two parallel cells of subsurface vertical flow (VSF), and one of horizontal subsurface flow (HSF), called hybrid system. The water flows horizontally through the porous media and the plants roots in the HSF, and are permanently flowed. The constant inflow is done by a Mariotte bottle. In the VSF the water flow is vertical and intermittent. The system can work with a direct and inverse mode flow, and it is designed to be used with two different flows, the normal one of 50 l/day and the winter one of 594 l/day. The plant is designed to treat grey water to reuse it after. Grey water is defined as the urban wastewater that includes water from bats, showers, hand basins, washing machines. The hydraulic circuit has been designed and constructed, using plastic pipes, pumps, plastic barrels, etc. The electrical circuit connects every timer to each pump. To set the flow the timers have to be programmed. The system has been studied by hydraulic balances, and a simulation program has been done according to the system limitations. The timing has been set and the plant has been started up with the direct mode and the normal operation flow with tap water. In other studying line, it has been done a literature review of constructed wetlands plants species to select them for the pilot plant according to the needs of our system: by their natural habitat, their removing capacity, their shape and measure. There have been 4 species selected: Phragmites australis, Typha latifolia, Carex elata and Juncus effusus. It has been done a review of the germination tests processes and a research of the optimum conditions of germination of the selected plants. Seeds of Typha latifolia were collected from the nature on November and after germinated. There have been done 4 germination tests, each one with distillate water and grey water. The capsules were placed under the fluorescents with constant light and the room temperature of 14-25ºC. The percentage of germinated seeds has been more with distillate water than in grey water. The conclusion obtained from the tests done, it is that the best way to germinate is with constant light, with filter paper on a soil pot, and keeping them watered frequently. The germinated plants are going to be used in the future in the pilot plant.