Control and separation of algae particles from WSP effluent by using floating aquatic plant root mats

2001 ◽  
Vol 43 (11) ◽  
pp. 315-322 ◽  
Author(s):  
Y. Kim ◽  
W.-J. Kim ◽  
P.-G. Chung ◽  
W. O. Pipes

In this paper, the potential uses of water hyacinth and its root mats for separating algae particles in the effluent from waste stabilization ponds (WSPs) were discussed. Pilot-scale integrated processes consisting of WSPs and multiple WHPs (water hyacinth ponds) were operated in order to extract effects of the root mats on the reduction of algae concentrations. Root mats in the bottom of WHPs separated significant amount of the algae cells through attachment as the effluent from WSPs passed through them. Attachment of the algae particles to the surface of live roots was found to be similar to adsorption phenomena but it lasted even at saturation, probably due to the continuous reproduction of active attachment sites by detachment and growth of the roots. Additionally, this paper discusses attachment mechanisms and other issues concerning design and polishing of the WSPs effluent by WHPs.

2002 ◽  
Vol 45 (1) ◽  
pp. 103-110 ◽  
Author(s):  
E. Giraldo ◽  
A. Garzón

The potential application of Water Hyacinth (Eichhornia crassipes) in organic matter degradation, sedimentation, nutrient and heavy metal absorption and sulfur reduction in the Muña Reservoir has been tested in experimental lagoons. The lagoons were operated at hydraulic retention times (HRT) of 6, 9 and 15 days. One lagoon was covered with Water Hyacinth, which is naturally growing in the Muña Reservoir, while another lagoon was operated as a conventional oxidation pond. The Water Hyacinth lagoon had better removal efficiencies for almost all parameters measured: BOD5, total suspended solids, COD, nitrogen, phosphorus and heavy metals. The oxidation lagoon was facultative for HRT of 9 and 15 days, and anoxic when operated at 6 days HRT. At HRT of 15 days the water quality in the effluent of the covered lagoon corresponded to 12 mg/l of BOD, 6 mg/l of suspended solids and 0.8 mg/l of hydrogen sulfide. Hydrogen sulfide levels in the Muña reservoir can be substantially reduced at HRT higher than 15 days in both lagoons. The uncovered lagoon had better hydrogen sulfide removal during the day but presents high levels at night. If the hydraulic retention time in the Muña reservoir is increased, the water quality of the Bogota river can be substantially improved for all the HRTs tested in the pilot units. HRT seems to give a better prediction of overall effluent water quality than surface loading. More research is needed in order to define the optimum water hyacinth density in the Muña reservoir to determine its influence on the water quality of the effluent. The influence is expected to be negative due to an internal increase of BOD, solids, nutrients and metals loads due to plant decay.


2010 ◽  
Vol 61 (4) ◽  
pp. 995-1002 ◽  
Author(s):  
R. K. X. Bastos ◽  
M. L. Calijuri ◽  
P. D. Bevilacqua ◽  
E. N. Rios ◽  
E. H. O. Dias ◽  
...  

The results of a 20-month period study in Brazil were analyzed to compare horizontal-flow constructed wetlands (CW) and waste stabilization pond (WSP) systems in terms of land area requirements and performance to produce effluent qualities for surface water discharge, and for wastewater use in agriculture and/or aquaculture. Nitrogen, E. coli and helminth eggs were more effectively removed in WSP than in CW. It is indicated that CW and WSP require similar land areas to achieve a bacteriological effluent quality suitable for unrestricted irrigation (103E. coli per 100 mL), but CW would require 2.6 times more land area than ponds to achieve quite relaxed ammonia effluent discharge standards (20 mg NH3 L−1), and, by far, more land than WSP to produce an effluent complying with the WHO helminth guideline for agricultural use (≤1 egg per litre).


2004 ◽  
Vol 48 (11-12) ◽  
pp. 115-123 ◽  
Author(s):  
Y. Kim ◽  
D.L. Giokas ◽  
P.-G. Chung ◽  
D.-R. Lee

In this study it was demonstrated that when water hyacinth ponds (WHPs) are used for polishing the effluent from waste stabilization ponds (WSPs), suspended solids (mostly algal particles) are efficiently separated, which also resulted in the reduction of insoluble forms of COD and nutrients. The high pH of the WSPs effluent was easily adjusted to 6-7 as it passed through the WHPs. However, the use of water hyacinth rapidly reduced dissolved oxygen at the first cell to less than three mg/L or very frequently to a level of anaerobic state. Reduction of suspended solids at the WHPs mainly depends on the detention time and pH. An empirical separation model incorporating the detention time and pH dependence was developed.


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