HYDRAULIC CONDUCTIVITY VARIABILITY IN HORIZONTAL SUBSURFACE FLOW CONSTRUCTED WETLANDS

Baptestini, Gheila C. F.; Matos, Antonio T.; Martinez, Mauro A.; Borges, Alisson C.; Matos, Mateus P.

doi:10.1590/1809-4430-Eng.Agric.v37n2p333-342/2017

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Scientific Paper, Sanitation and Ambient Control • Eng. agríc. 37 (02) • Mar-Apr 2017 • https://doi.org/10.1590/1809-4430-Eng.Agric.v37n2p333-342/2017 copy

HYDRAULIC CONDUCTIVITY VARIABILITY IN HORIZONTAL SUBSURFACE FLOW CONSTRUCTED WETLANDS

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

Many modifications in hydrodynamic conditions occur inside the bed of a horizontal subsurface flow constructed wetland (HSSF–CW) in operation. Studies on hydraulic conductivity measurement techniques in HSSF–CW are imperative since the monitoring of flow conditions is essential for understanding and controlling its clogging. This study aimed to assess the hydrodynamic behavior in HSSF–CW by means of saturated hydraulic conductivity (K_s) analysis. For this, six HSSF–CW were used: two non-cultivated (control), two cultivated with Tifton 85 (Cynodon spp.), and two cultivated with alligator weed (Alternanthera philoxeroides). Application of swine wastewater (SW) in HSSF–CW started on June 15, 2011, with K_s measurement period between September 9 and November 11, 2011, in which five measurements were performed in different positions along the system length and over experimental period in order to assess the effects of vegetation, position, and time factors on this variable. K_s values ranged from 1,392 to 2,834 m d⁻¹. Plant presence led to K_s decreasing in the systems, but cultivated species had no influence on this variable. Monitoring time of HSSF–CW was no longer enough to provide a reduction in K_s, at 10% probability level.

KEYWORDS:
hydrodynamic conditions; clogging; constructed wetlands; wastewater treatment

pH	EC	COD	BOD	TSS	TN	P	K	Na
pH	dS m⁻¹	------------------------------------------------------mg L⁻¹------------------------------------------------------
8.0 ± 0.2	3.81 ± 0.38	1.188 ± 572	818 ± 570	198 ± 64	437 ± 73	50 ± 5	79 ± 12	81 ± 27

	QA	HDT	OLR_s	OLR_T	SLR_T
	(m³ d⁻¹)	(d)	-----------------g m⁻² d⁻¹)-----------------
Average values	0.069 ± 0.014	2.9 ± 0.6	56.4 ± 11.4	3,272	792

Source of variation	DF	Mean square
Vegetation (V)	2	4,952,972.0^° *ns, , and °** not significant and significant at 5 and 10% probability level, respectively, by the F test.
Error (a)	3	1,285,998.0
Position (P)	2	31,908.2^ns *ns, , and °** not significant and significant at 5 and 10% probability level, respectively, by the F test.
P × V	4	2,515,700.0^* *ns, , and °** not significant and significant at 5 and 10% probability level, respectively, by the F test.
Error (b)	6	960,356.8
Time (T)	4	57,817.1^ns *ns, , and °** not significant and significant at 5 and 10% probability level, respectively, by the F test.
T × V	8	40,653.0^ns *ns, , and °** not significant and significant at 5 and 10% probability level, respectively, by the F test.
T × P	8	41,066.5^ns *ns, , and °** not significant and significant at 5 and 10% probability level, respectively, by the F test.
T × P × V	16	38,625.2^ns *ns, , and °** not significant and significant at 5 and 10% probability level, respectively, by the F test.
Residual	36	39,069.2
CV plot	53.93%
CV subplot	46.61%
CV sub-subplot	9.40%

Treatment	Position
Treatment	1^st third	2^nd third	3^rd third
SP	2,123 aA	2,682 aA	2,834 aA
P1	2,390 aA	2,257 aAB	1,392 aB
P2	1,824 aA	1,449 aB	1,973 aAB

Plant	Dry matter productivity (t ha⁻¹)
Plant	1^st third	2^nd third	3^rd third
Tifton 85	8.2	9.8	8.9
Alligator weed	6.0	7.4	6.7

Associação Brasileira de Engenharia Agrícola SBEA - Associação Brasileira de Engenharia Agrícola, Departamento de Engenharia e Ciências Exatas FCAV/UNESP, Prof. Paulo Donato Castellane, km 5, 14884.900 | Jaboticabal - SP, Tel./Fax: +55 16 3209 7619 - Jaboticabal - SP - Brazil
E-mail: revistasbea@sbea.org.br

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[1] * Corresponding author. Universidade Federal de Minas Gerais/ Belo Horizonte - MG, Brasil. E-mail: atmatos@desa.ufmg.br