The effect of baffles on algal-bacterial biofilm structure and composition of zooplankton in wastewater stabilization ponds

2011 ◽  
pp. 31-58
Keyword(s):  
Bacterial Biofilm ◽  
Stabilization Ponds ◽  
Biofilm Structure ◽  
Wastewater Stabilization Ponds

scholarly journals Influence of Rhamnolipids and Ionic Cross-Linking Conditions on the Mechanical Properties of Alginate Hydrogels as a Model Bacterial Biofilm

2021 ◽  
Vol 22 (13) ◽  
pp. 6840
Author(s):  
Natalia Czaplicka ◽  
Szymon Mania ◽  
Donata Konopacka-Łyskawa
Keyword(s):  
Mechanical Properties ◽  
Pure Water ◽  
Testing Machine ◽  
Bacterial Biofilm ◽  
Ion Trapping ◽  
Cross Linking ◽  
Box Behnken Design ◽  
Compression Load ◽  
Alginate Hydrogels ◽  
Biofilm Structure

The literature indicates the existence of a relationship between rhamnolipids and bacterial biofilm, as well as the ability of selected bacteria to produce rhamnolipids and alginate. However, the influence of biosurfactant molecules on the mechanical properties of biofilms are still not fully understood. The aim of this research is to determine the effect of rhamnolipids concentration, CaCl2 concentration, and ionic cross-linking time on the mechanical properties of alginate hydrogels using a Box–Behnken design. The mechanical properties of cross-linked alginate hydrogels were characterized using a universal testing machine. It was assumed that the addition of rhamnolipids mainly affects the compression load, and the value of this parameter is lower for hydrogels produced with biosurfactant concentration below CMC than for hydrogels obtained in pure water. In contrast, the addition of rhamnolipids in an amount exceeding CMC causes an increase in compression load. In bacterial biofilms, the presence of rhamnolipid molecules does not exceed the CMC value, which may confirm the influence of this biosurfactant on the formation of the biofilm structure. Moreover, rhamnolipids interact with the hydrophobic part of the alginate copolymer chains, and then the hydrophilic groups of adsorbed biosurfactant molecules create additional calcium ion trapping sites.

Nitrification in bulk water and biofilms of algae wastewater stabilization ponds

2007 ◽  
Vol 55 (11) ◽  
pp. 93-101 ◽  
Author(s):  
M.A. Babu ◽  
M.M. Mushi ◽  
N.P. van der Steen ◽  
C.M. Hooijmans ◽  
H.J. Gijzen
Keyword(s):  
Model Equation ◽  
Bulk Water ◽  
Balance Model ◽  
Nitrification Rate ◽  
Relative Contribution ◽  
Activity Test ◽  
Stabilization Ponds ◽  
Wide Range ◽  
Water Columns ◽  
Wastewater Stabilization Ponds

Nitrogen removal in wastewater stabilization ponds is poorly understood and effluent monitoring data show a wide range of differences in ammonium. For effluent discharge into the environment, low levels of nitrogen are recommended. Nitrification is limiting in facultative wastewater stabilization ponds. The reason why nitrification is considered to be limiting is attributed to low growth rate and wash out of the nitrifiers. Therefore to maintain a population, attached growth is required. The aim of this research is to study the relative contribution of bulk water and biofilms with respect to nitrification. The hypothesis is that nitrification can be enhanced in stabilization ponds by increasing the surface area for nitrifier attachment. In order to achieve this, transparent pond reactors representing water columns in algae WSP have been used. To discriminate between bulk and biofilm activity, 5-day batch activity tests were carried out with bulk water and biofilm sampled. The observed value for Rnitrbulk was 2.7 × 10−1 mg-N L−1 d−1 and for Rbiofilm was 1,495 mg-N m−2 d −1. During the 5 days of experiment with the biofilm, ammonia reduction was rapid on the first day. Therefore, a short-term biofilm activity test was performed to confirm this rapid decrease. Results revealed a nitrification rate, Rbiofilm, of 2,125 mg-N m−2 d−1 for the first 5 hours of the test, which is higher than the 1,495 mg-N m−2 d−1, observed on the first day of the 7-day biofilm activity test. Rbiofilm and Rnitrbulk values obtained in the batch activity tests were used as parameters in a mass balance model equation. The model was calibrated by adjusting the fraction of the pond volume and biofilm area that is active (i.e. aerobic). When assuming a depth of 0.08 m active upper layer, the model could describe well the measured effluent values for the pond reactors. The calibrated model was validated by predicting effluent Kjeldahl nitrogen of algae ponds in Palestine and Colombia. The model equation predicted well the effluent concentrations of ponds in Palestine.

Model of Daphnia populations for wastewater stabilization ponds

1995 ◽  
Vol 29 (1) ◽  
pp. 195-208 ◽  
Author(s):  
Charles J. Hathaway ◽  
Heinz G. Stefan
Keyword(s):  
Stabilization Ponds ◽  
Wastewater Stabilization Ponds

scholarly journals Changes in Bacterial Communities During Treatment of Municipal Wastewater in Arctic Wastewater Stabilization Ponds

2021 ◽  
Vol 3 ◽  
Author(s):  
Yannan Huang ◽  
Colin M. Ragush ◽  
Lindsay H. Johnston ◽  
Michael W. Hall ◽  
Robert G. Beiko ◽  
...  
Keyword(s):  
Water Quality ◽  
16S Rrna ◽  
Treatment Outcomes ◽  
Bacterial Communities ◽  
Municipal Wastewater ◽  
Quality Data ◽  
Water Quality Data ◽  
Stabilization Ponds ◽  
Wastewater Stabilization Ponds ◽  
Raw Wastewater

Wastewater stabilization ponds (WSPs) are commonly used to treat municipal wastewater in the Canadian Arctic. Bacterial community structure and functionality remain mostly uncharacterized for arctic WSPs, yet are presumed important for treatment outcomes during the 3-month summer treatment season with open water in the WSPs. The objective of this study was to investigate treatment performance and related temporal and spatial changes in the structure and putative function of bacterial communities during treatment of municipal wastewater in the WSPs of Pond Inlet and Clyde River, Nunavut over two consecutive summer treatment seasons. Influent raw wastewater contained a high organic load and large bacterial communities (~9 log 16S rRNA copies/mL) belonging mainly to Proteobacteria. Although designed to be facultative ponds, both WSPs remained anaerobic with neutral pH values (7.5–7.8) throughout the summer treatment season. Water quality data showed that nutrients [measured as carbonaceous biological oxygen demand (CBOD5)], total suspended solids, and total ammonia nitrogen were progressively reduced during treatment in the ponds as the summer progressed. The pond bacterial population size and species richness depended on the pond temperature (2–18°C), with 8.5 log 16S rRNA copies/mL and the largest alpha diversities (Shannon-Wiener index of 4-4.5) observed mid-season (late July). While the phylogenetic beta diversity in raw wastewater from the two locations remained similar, pond bacterial communities underwent significant (p < 0.05) changes to dominance of Comamonadaceae, Geobacteracea, and Porphyromonadaceae. Multivariate distance based redundancy analysis and predicted gene functionalities in the microbiota agreed with water quality results that microbial removal of nutrients (e.g., CBOD5) peaked in the middle of the summer coinciding with the treatment period with the highest pond temperatures. Information from this study will be useful for further development of models to predict biological treatment outcomes, which could be used to size and assess the feasibility of WSPs in extreme climates. Higher pond temperatures resulted in optimal biological processes and nutrient removal in the middle of the summer. While it is challenging to control environmental factors in a passive wastewater treatment system there are some design considerations that could be used to optimize temperature regimes, such as the depth of the pond.

Spectroscopic Indicators for Cytotoxicity of Chlorinated and Ozonated Effluents from Wastewater Stabilization Ponds and Activated Sludge

2018 ◽  
Vol 52 (5) ◽  
pp. 3167-3174 ◽  
Author(s):  
Nedal Massalha ◽  
Shengkun Dong ◽  
Michael J. Plewa ◽  
Mikhail Borisover ◽  
Thanh H. Nguyen
Keyword(s):  
Activated Sludge ◽  
Stabilization Ponds ◽  
Wastewater Stabilization Ponds
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