Post-treatment of UASB reactor effluent in waste stabilization ponds and in horizontal flow constructed wetlands: a comparative study in pilot scale in Southeast Brazil

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).

1995 ◽  
Vol 31 (12) ◽  
pp. 201-210 ◽  
Author(s):  
C. Polprasert ◽  
S. Sookhanich

This study investigated the efficiency and performance of attached-growth waste stabilization ponds (AGWSP) treating a high-strength phenolic wastewater. The experiments employed 4 laboratory-scale pond units installed with an artificial attached-growth media. A control pond unit without attached-growth media (or WSP) was run in parallel for data comparison. The experimental results revealed that the AGWSP units could remove about 99, 50, 45 and 28% of phenol when operated at influent phenol concentrations of 500, 1000, 1500 and 2000 mg/l (corresponding to organic loading rates (OLR) of 180, 360, 540 and 720 kg COD/(ha.day), respectively); these removal efficiencies were consistently higher than those observed in the WSP unit. The influent phenol concentrations of 1000-2000 mg/l resulted in some toxic effects and over loading to the pond system, causing the phenol removal efficiencies to decrease. The amount of phenol loss from the pond water through volatilization was found to be approximately 10%. A relationship between phenol removal rates (excluding volatilization) and phenol dosages to the AGWSP was developed. The superior performance of the AGWSP over the WSP appeared to be due to the biofilm biomass growing on the attached-growth media surface, resulting in increased potential biomass in the pond water.


2005 ◽  
Vol 51 (12) ◽  
pp. 69-74 ◽  
Author(s):  
H.W. Pearson ◽  
S.T. Silva Athayde ◽  
G.B. Athayde ◽  
S.A. Silva

Studies on experimental primary facultative ponds showed that varying the depth from 1.25 m to 2.3 m had no effect on the rates of BOD removal. In contrast k values for FC removal rates were higher in the shallower (1.25 m) facultative ponds. The risk of odour release via H2S production was higher in the 2.2 m ponds than the 1.25 m ponds and NH3 removal was much better in the 1.25 m facultative ponds. A comparison of the efficiency of shallow 5-pond series (1.0 m and 0.61 m deep) with a 2.2 m deep series showed that the shallow systems were more efficient at FC removal, but the deeper series actually saved land area for the same FC final effluent quality under tropical conditions. However, efficient nutrient removal (N and P) only occurred in the shallow series and effluent standards for nutrient concentrations are unlikely to be met by 2.2 m deep 5-pond series in contrast to the norms for pathogen removal.


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.


2014 ◽  
Vol 13 (2) ◽  
pp. 446-458 ◽  
Author(s):  
Florentina Zurita ◽  
Alejandra Carreón-Álvarez

Three pilot-scale two-stage hybrid constructed wetlands were evaluated in order to compare their efficiency for total coliforms (TCol) and Escherichia coli removal and to analyze their performances in two 1-year periods of experimentation. System I consisted of a horizontal flow (HF) constructed wetland (CW) followed by a stabilization pond. System II was also configured with a HF CW as a first stage which was then followed by a vertical flow (VF) CW as a second stage. System III was configured with a VF CW followed by a HF CW. In the first year of evaluation, the HF–VF system was the most effective for TCol removal (p < 0.05) and achieved a reduction of 2.2 log units. With regard to E. coli removal, the HF–VF and VF–HF systems were the most effective (p < 0.05) with average reductions of 3.2 and 3.8 log units, respectively. In the second year, the most effective were those with a VF component for both TCol and E. coli which underwent average reductions of 2.34–2.44 and 3.44–3.74 log units, respectively. The reduction achieved in E. coli densities, in both years, satisfy the World Health Organization guidelines that require a 3–4 log unit pathogen reduction in wastewater treatment systems.


2003 ◽  
Vol 3 (4) ◽  
pp. 193-200 ◽  
Author(s):  
G.A. Parissopoulos ◽  
A. Papadopoulos ◽  
F. Papadopoulos ◽  
A. Karteris

The performance of three waste stabilization ponds (WSP) treatment units (lines A, B, C) for a period of two years is presented. The above units were part of a research and demonstration project in North Greece concerning wastewater treatment with natural systems and effluent reuse for irrigation. Line A consisted of a deep anaerobic pond followed by a facultative and two maturation ponds. The anaerobic pond supplied with 120 m3/d was also feeding line B at a ratio 1:3 (line A: line B). Line B had the same design features with line A but with a recirculation of effluent. The third unit fed with primary treated effluent at a rate of 50m3/d from the WWTP of Thessaloniki was consisted of a facultative and two maturation ponds. In the anaerobic pond the BOD5, COD, SS, TC and FC mean reduction was 28%, 42%, 58%, 31% and 36% for the cold period (T<10°C) and 45%, 53%, 72%, 67% and 71% for the warm period (T>10°C) respectively. In line A, the BOD5, COD, SS, TC and FC total reduction was 98%, 89%, 93%, 99.99% and 99.99% for the cold and 98%, 85%, 88%, 99.99% and 99.99% for the warm period. In line B the reduction was 92%, 86%, 88%, 98.5% and 98.82% for the cold and 96%, 88%, 83%, 99.95% and 99.97% for the warm period. In line C the reduction of the same parameters was 92%, 64%, 40%, 99.88% and 99.96% for the cold and 92%, 59%, 22%, 99.99% and 99.99% for the warm period. The effluent quality was further improved with the use of a storage reservoir and a slow sand filter and reused successfully for crop irrigation.


1995 ◽  
Vol 31 (12) ◽  
pp. 275-284 ◽  
Author(s):  
N. G. H. Dixo ◽  
M. P. Gambrill ◽  
P. F. C. Catunda ◽  
A. C. van Haandel

A series of four pilot-scale, shallow waste stabilization ponds (WSPs), comprising one facultative followed by three maturation ponds with a total design retention time of 20 days, was monitored to observe its ability to remove pathogenic organisms from the effluent of an upflow anaerobic sludge blanket (UASB) digester. The UASB reactor received strong domestic wastewater from the shanty district of a city in north-east Brazil. The raw wastewater had a very high concentration of intestinal nematode eggs of which, on average, 89.6 percent were removed in the UASB reactor. No intestinal nematode eggs were recovered in the effluent of the first maturation pond, making it suitable for restricted irrigation. The removal of eggs in the first pond exceeded predictions made using a recently published model. Faecal coliforms (FC) were reduced by 4.7 log units on average in the pond series -- the final effluent being suitable for unrestricted irrigation. pHs exceeding 10 were attained in the final maturation pond at the sunniest time of day. There was a significant correlation between levels of pH and FC in the ponds, the latter being ≤ 1000 per 100 ml when the former was ≥ 9.1. The removal of FC in the ponds was linear over the range of pH encountered. The findings are consistent with recent work by others suggesting that FC removal in ponds is multi-factorial. The UASB reactor, with a retention time of 7 h, is an efficient primary treatment alternative to an anaerobic pond in a WSP series receiving an extremely strong domestic wastewater. There are potential advantages of using the former in preference to the latter in a series of ponds.


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