scholarly journals Improving the performance of waste stabilization ponds in an arid climate

Author(s):  
Badre Achag ◽  
Hind Mouhanni ◽  
Abdelaziz Bendou

Abstract In many parts of the world, waste stabilization ponds (WSPs) are currently the preferred wastewater treatment method for municipal wastewater. The objective of this research is to examine the performance of a WSP in an arid climate region and to identify ways to improve its purification efficiency so that it can meet the criteria for reuse. The results attributed the poor performance to both improper process and physical design after 12 months of physicochemical and bacteriological analyses, as well as monitoring of operation, maintenance and loading rates. In tertiary treatment, maturation ponds are added, an increase in the capacity of the station, and management of the flow rate and retention time for each pond. By simulating the new WSP with GPS-X, the best pond area ratio obtained is 2.5 m2/capita, with a retention time of 4 days for anaerobic ponds, 20 days for facultative ponds and 3 days for two maturation ponds in series, which is suitable and provides reduction rates of BOD and fecal coliforms of 95 and 99%, respectively, with an average effluent concentration of 20 mg/L and 195 CFU. According to the results, well-maintained WSPs provide a viable, self-sufficient and environmentally friendly wastewater treatment solution for irrigation water supply in dry areas.

1986 ◽  
Vol 18 (10) ◽  
pp. 31-35 ◽  
Author(s):  
J. I. Oragui ◽  
T. P. Curtis ◽  
S. A. Silva ◽  
D. D. Mara

The removal of excreted bacteria (faecal coliforms, faecal streptococci, Clostridium perfringens, total and sorbitol-fermenting bifidobacteria, salmonellae and thermophilic campylobacters) and viruses (enterovirus and rotavirus) in a series of deep anaerobic, facultative and maturation ponds (depth range: 2.8 - 3.4 m), with an overall retention time of 21 days and a mean mid-depth temperature of 27°C, was studied. Thermophilic campylobacters, bifidobacteria and salmonellae were not detected after 11, 16 and 21 days' retention respectively. Faecal coliforms, faecal streptcocci and Cl. perfringens were reduced by 4, 4 and 2 orders of magnitude respectively, and enteroviruses and rotaviruses both by 3 orders. The results indicate that pathogen removal in deep ponds is similar to that in ponds of normal depth.


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.


1987 ◽  
Vol 19 (3-4) ◽  
pp. 569-573 ◽  
Author(s):  
J. I. Oragui ◽  
T. P. Curtis ◽  
S. A. Silva ◽  
D. D. Mara

The removal of excreted bacteria (faecal coliforms, faecal streptococci, Clostridium perfringens, total and sorbitol-fermenting bifidobacteria, salmonellae and thermophilic campylobacters) and viruses (enterovirus and rotavirus) in a series of deep anaerobic, facultative and maturation ponds (depth range: 2.8 - 3.4 m), with an overall retention time of 21 days and a mean mid-depth temperature of 27°C, was studied. Thermophilic campylobacters, bifidobacteria and salmonellae were not detected after 11, 16 and 21 days' retention respectively. Faecal coliforms, faecal streptcocci and Cl. perfringens were reduced by 4, 4 and 2 orders of magnitude respectively, and enteroviruses arid rotaviruses both by 3 orders. The results indicate that pathogen removal in deep ponds is similar to that in ponds of normal depth.


2007 ◽  
pp. 419-428
Author(s):  
R.M. Al-Sa 'ed ◽  
N. Mahmoud ◽  
A. Abu-Madi ◽  
O.R. Zimmo

This paper evaluates the feasibility of using local rock filter as natural media in waste stabilization ponds, A pilot-scale algae-rock filter ponds (ARPs) system was investigated, in parallel with algae-based ponds (ABPs) over a period of 6 months to evaluate the treatment efficacy of both systems. Each system entailed 4 equal ponds in series and was continuously fed with domestic wastewater from Birzeit University. The removal rates of organic matter, nutrients and faecal coliforms were monitored within each treatment system. The results obtained revealed that ARPs system was more efficient in the removal of organic matter (TSS and COD; 86% and 84%, respectively) and fecal coliforms (4 log10) than ABPs (81%, 81%, 3 log10, respectively). Nitrogen was reduced in the ARPs to an average of24 mg N/1; in contrast the ABPs effluent contained 32 mg N/1. Compared to ABP system, passive aerated ARPs option is an efficient, a low-cost and land-saving alternative with effluent quality suitable for restricted agricultural use in rural areas.


Author(s):  
Monica Gromala ◽  
Josh D. Neufeld ◽  
Brendan J. McConkey

Wastewater management in the Canadian Arctic is challenging due to climate extremes, small population sizes, and lack of conventional infrastructure for wastewater treatment. Although many Northern communities use waste stabilization ponds (WSPs) as their primary form of wastewater treatment, few studies have explored WSP microbial communities and assessed effluent impacts on receiving waters from a microbiological perspective. Here we used 16S rRNA gene and metagenome sequencing to characterize WSP and receiving water microbial communities for two time points bracketing the spring WSP thaw in Baker Lake (Nunavut) and compared these results to other Nunavut WSPs in Cambridge Bay and Kugluktuk. Most amplicon sequence variants (ASVs) recovered from these WSP samples belonged to the phylum Proteobacteria, with considerable variation between the three locations and only six ASVs shared among the WSPs at >0.2% relative abundance. Wastewater indicator ASVs for the Baker Lake WSP were identified and few indicator ASVs were detected in samples originating from other upstream or downstream sites. The metagenomic data revealed a strong enrichment of antibiotic resistance genes for WSP samples, relative to downstream and reference samples, especially for genes associated with macrolide resistance. Together our results provide a baseline characterization for WSP microbial communities, demonstrate how indicator ASVs can be used to monitor attenuation and dilution of effluent microorganisms, and reveal that WSPs can serve as hotspots for antibiotic resistance genes. Importance Given that the microbial communities of Arctic waste stabilization ponds (WSPs) are poorly studied to date, our characterization of multiple WSP systems and time points provides important baseline data that will assist with ongoing monitoring of effluent impacts on downstream aquatic ecosystems in the Arctic. This research also identifies indicator ASVs of WSPs that will be helpful for future monitoring for WSP effluent attenuation and demonstrates that WSP microbial communities are enriched in antibiotic resistance genes. Given operational and infrastructure changes anticipated for wastewater treatment systems in the Arctic, baseline data such as these are essential for further development of safe and effective wastewater treatment systems.


Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1410 ◽  
Author(s):  
Long Ho ◽  
Cassia Pompeu ◽  
Wout Van Echelpoel ◽  
Olivier Thas ◽  
Peter Goethals

In a way to counter criticism on low cost-effective conventional activated sludge (AS) technology, waste stabilization ponds (WSPs) offer a valid alternative for wastewater treatment due to their simple and inexpensive operation. To evaluate this alternative with respect to its robustness and resilience capacity, we perform in silico experiments of different peak-load scenarios in two mathematical models representing the two systems. A systematic process of quality assurance for these virtual experiments is implemented, including sensitivity and identifiability analysis, with non-linear error propagation. Moreover, model calibration of a 210-day real experiment with 31 days of increased load was added to the evaluation. Generally speaking, increased-load scenarios run in silico showed that WSP systems are more resilient towards intermediate disturbances, hence, are suitable to treat not only municipal wastewater, but also industrial wastewater, such as poultry wastewater, and paperboard wastewater. However, when disturbances are extreme (over 7000 mg COD·L−1), the common design of the natural system fails to perform better than AS. Besides, the application of sensitivity analysis reveals the most influential parameters on the performance of the two systems. In the AS system, parameters related to autotrophic bacteria have the highest influence on the dynamics of particulate organic matter, while nitrogen removal is largely driven by nitrification and denitrification. Conversely, with an insignificant contribution of heterotrophs, the nutrient removal in the pond system is mostly done by algal assimilation. Furthermore, this systematic model-based analysis proved to be a suitable means for investigating the maximum load of wastewater treatment systems, and from that avoiding environmental problems and high economic costs for cleaning surface waters after severe overload events.


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