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Laminar height variation on pathogen removal and nitrogen in subsurface vertical flow
constructed wetlands
M. González, D. Paredes
Facultad de Ciencias Ambientales, Universidad Tecnológica de Pereira.
Carrera 27 #10-02 Barrio
Álamos, Pereira, Risaralda-Colombia. AA: 97 – Código postal: 660003.
Abstract
Contamination of water sources caused by a variety of human activities, is one of the biggest
environmental problems that are involved countries around the world, especially in areas like
Latin America, where improper disposal of spills is presented as the water domestic and
industrial wastes, mining, deforestation and erosion processes related pollution by surface runoff
and little or no management of solid waste and leachate (Galvis, 2009).
Constructed wetlands have become a viable alternative for treating liquid waste, trying to
"emulate" the complex relationships and reactions that occur in these ecosystems (Arias and Brix,
2003). Vertical Subsurface Flow (VSSF – CW) systems are a type of constructed wetlands whose
units can be affected by different hydraulic parameters, including water level, because it plays an
important role in the ecological functions and can harm livelihoods associated vegetation, and the
impact on the hydraulic residence time (HRT), one of the main operational parameters.
These systems are characterized by a short retention time, where the wastewater is filtered
through a pad and contact microbial communities in the roots and associated vegetation in the
filter media to maximize the depth of the unit. In VSSF – CW systems can occurs different
physical, chemical and biological processes which seek to promote the removal of organic matter,
nutrients and pathogens, through the presence and / or absence of oxygen facilitated by changes
in the level of residual water within the wetlands.
In order to evaluate the effect of water level the removal efficiency of contaminants and
pathogens in VSSF – CW full-scale systems with different levels of residual water (0 – 40 – 65
cm) were operated. The importance of this research is based on the natural systems such as
constructed wetlands, are presented as one, both environmentally and economically effective and
sustainable eco-technological choice within the local context. In addition, there are few
experiences full scale on the efficiency of constructed wetlands.
This research was developed in Domestic Wastewater Treatment Plant (WWTP) of the
Magnetron Electromechanical Company where it was determined that their performance as to
ammonia transformation achieved through vertical constructed wetland, 0 cm water level, was 14
g/m
2
d. This parameter showed significant differences between the treatments applied
(p=0.00<0.05). In contrast, total nitrogen, no significant differences were seen in the average of
the data obtained (p=0.66>0.05).
On removal of organic matter, in terms of BOD, it was found that significant differences occurred
(p=0.03<0.05), whereas for COD and TSS showed no significant differences (p=0.07>0.05 –
