טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentSchreiber Joseph
SubjectWastewater Purification by Aquatic Plants
DepartmentDepartment of Civil and Environmental Engineering
Supervisor Mr. Yoram Zimmels (Deceased)
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Abstract

The potential of floating and emergent aquatic macrophytes and electro coagulation (EC) process, to reduce high organic loads that characterize winery wastewater (WWW), is demonstrated in this work

Winery wastewater (WWW) effluents are characterized by pH 4 to 5, high biochemical oxygen demand (BOD) and chemical oxygen demand (COD) that falls outside the limits set by local authorities.

The aquatic plants selected for this study included: floating plants - Water Hyacinth and Pennywort, emergent plants - Cattail, Giant reed, and a mixture of two herbaceous plants.

Two sets of batch experiments of EC (electro coagulation ) were performed in the laboratory in order to examine the EC process as a prelimenary treatment of row WWW.  A 40% - 50% decrease of BOD and COD was observed from initial value of 5,000 and 10,000 mgL-1 , respectively.

Two sets of batch experiments with aquatic floating plants were performed in the laboratory and two in the field. In raw WWW, (COD, 5.6 gL-1), growth inhibition of both plants was observed. In terms of reductions of BOD, COD and TSS, both plants performed better in diluted than in raw WWW. At 1:1 and 1:3 dilution WWW and applied aeration, 95.9 - 97 % of the COD was removed after 23 days, in the presence of both plants. A clear effect of circulation and aeration on contaminants removal was observed.

Five sets of experiments with emergent plants were performed. Three containers were used to represent the process occurring in constructed wetlands consisting of vertical subsurface-flow root zone systems with emergent plants. Three containers that were filled with bed medium without plants were used as control.

 The capacity of the emergent plants to remove high organic loads from WWW, at enhanced kinetics, was demonstrated. In the presence of Reed and a mixture of two herbaceous plants, 83 - 99 % of the COD were removed within a period of 24-29 days. The emergent plants proved to be effective even at record high levels of COD. At initial level of 16,460 mgL-1 the COD was brought down to 2,870 mgL-1 after 24 days, while 12,230 mgL-1 was lowered to 106 mgL-1, giving 99.1 % removal from the highly contaminated WWW. A daily removal rates as high as 2000 mgL-1 in the first treatment days was observed. 

The capacity of emergent and floating plants to purify WWW to levels required by national guidelines was demonstrated in this research.