The performance of a high-rate algal pond in the Moroccan climate

1995 ◽  
Vol 31 (12) ◽  
pp. 67-74 ◽  
Author(s):  
B. El Hamouri ◽  
J. Jellal ◽  
K. Khallayoune ◽  
A. Benkerroum ◽  
A. Hajli ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Hydraulic Retention Time ◽  
Climatic Conditions ◽  
High Rate ◽  
Biological Processes ◽  
Faecal Coliforms ◽  
First Order ◽  
Helminth Eggs ◽  
Bod Removal

The performance of a wastewater treatment system consisting of an anaerobic pond followed by a high-rate algal pond (HRAP) is presented. The results allowed establishment of a statistical model for HRAP design in similar climatic conditions. The results also allowed the determination of the first-order constant of faecal coliforms (FC) die-off. This constant was found to be 24.7 and 0.97 d-1, respectively, in the hot and the cold seasons. Also, some results are presented on the comprehension of the biological processes which take place in a homogeneous HRAP. They indicate that BOD and FC removals are separated in the time and that BOD removal always precedes FC die-off. Finally the results show that the helminth eggs were completely removed within an overall hydraulic retention time of 8.2 days.

Viability of nematode eggs in high rate algal ponds: the effect of physico-chemical conditions

2000 ◽  
Vol 42 (10-11) ◽  
pp. 371-374 ◽  
Author(s):  
S. Araki ◽  
J. M. González ◽  
E. de Luis ◽  
E. Bécares
Keyword(s):  
Hydraulic Retention Time ◽  
Pilot Scale ◽  
High Rate ◽  
Sterile Water ◽  
Egg Viability ◽  
High Rate Algal Ponds ◽  
Helminth Eggs ◽  
Physico Chemical ◽  
Nematode Eggs ◽  
Chemical Conditions

The viability of Parascaris equorum eggs was studied in two experimental pilot-scale high-rate algal ponds (HRAPs) working in parallel with 4 and 10 days hydraulic retention time respectively. Semi-permeable bags of cellulose (15000 daltons pore size) were used to study the effect of physico-chemical conditions on the survival of these helminth eggs. Three thousand eggs were used in each bag. Replicates of these bags were submerged for 4 and 10 days in the HRAPs and egg viability was compared with that in control bags submerged in sterile water. After 4 days exposure, 60% reduction in viability was achieved, reaching 90% after 10 days, much higher than the 16% and 25% found in the control bags for 4 and 10 days respectively. Ionic conditions of the HRAP may have been responsible for up to 50–60% of the egg mortality, suggesting that mortality due to the ionic environment could be more important than physical retention and other potential removal factors.

Algal biofuels from wastewater treatment high rate algal ponds

2011 ◽  
Vol 63 (4) ◽  
pp. 660-665 ◽  
Author(s):  
R. J. Craggs ◽  
S. Heubeck ◽  
T. J. Lundquist ◽  
J. R. Benemann
Keyword(s):  
Wastewater Treatment ◽  
Nutrient Removal ◽  
Large Scale ◽  
Low Cost ◽  
Algal Species ◽  
Climatic Conditions ◽  
Biofuel Production ◽  
High Rate ◽  
Algal Production ◽  
High Rate Algal Ponds

This paper examines the potential of algae biofuel production in conjunction with wastewater treatment. Current technology for algal wastewater treatment uses facultative ponds, however, these ponds have low productivity (∼10 tonnes/ha.y), are not amenable to cultivating single algal species, require chemical flocculation or other expensive processes for algal harvest, and do not provide consistent nutrient removal. Shallow, paddlewheel-mixed high rate algal ponds (HRAPs) have much higher productivities (∼30 tonnes/ha.y) and promote bioflocculation settling which may provide low-cost algal harvest. Moreover, HRAP algae are carbon-limited and daytime addition of CO2 has, under suitable climatic conditions, the potential to double production (to ∼60 tonnes/ha.y), improve bioflocculation algal harvest, and enhance wastewater nutrient removal. Algae biofuels (e.g. biogas, ethanol, biodiesel and crude bio-oil), could be produced from the algae harvested from wastewater HRAPs, The wastewater treatment function would cover the capital and operation costs of algal production, with biofuel and recovered nutrient fertilizer being by-products. Greenhouse gas abatement results from both the production of the biofuels and the savings in energy consumption compared to electromechanical treatment processes. However, to achieve these benefits, further research is required, particularly the large-scale demonstration of wastewater treatment HRAP algal production and harvest.

Wastewater Treatment by Infiltration Basins: Usefulness and Limits – Sewage Plant in Creances (France)

1991 ◽  
Vol 24 (9) ◽  
pp. 287-293 ◽  
Author(s):  
J. Carré ◽  
J. Dufils
Keyword(s):  
Wastewater Treatment ◽  
Ground Water ◽  
Surface Waters ◽  
Suspended Solid ◽  
Climatic Conditions ◽  
Faecal Coliforms ◽  
Total Removal ◽  
Dry Out ◽  
P Removal

The wastewater treatment by infiltration basins used in Créances (France) allows for the protection of the quality of surface waters. The infiltration leads to a total removal of suspended solid and of 80 to 85 % of COD initially present in the effluent. In summer N and P removal corresponds to two-thirds of the concentration of NH4+ and PO43− but in winter no removal is observed for these elements. Whatever the season removal of total coliforms, faecal coliforms and faecal streptococci is high and reaches 6 logs. A part of the contamination is transferred by renovated water into the unconfined ground water which lies at a depth of 6 m below the bottom of the basins. The effect of infiltration on the ground water quality includes an increase in overall mineralisation of the water and especially as regards nitrogen, anionic detergent and boron levels. Otherwise, difficulties of managing the plant result from the fast clogging of the basins because of a low removal of suspended solids in the pretreatment stage and from the climatic conditions which increase the time to dry out the cake.

Removal of pathogens from wastewaters by the root zone method (RZM)

1995 ◽  
Vol 32 (3) ◽  
pp. 211-218 ◽  
Author(s):  
Fermin Rivera ◽  
Alan Warren ◽  
Elizabeth Ramirez ◽  
Olivier Decamp ◽  
Patricia Bonilla ◽  
...  
Keyword(s):  
Root Zone ◽  
Climatic Conditions ◽  
Pathogenic Microorganisms ◽  
Faecal Coliforms ◽  
Treatment Efficiency ◽  
Zone Method ◽  
Free Living ◽  
Gravel Beds ◽  
Helminth Eggs ◽  
Better Than

Full-scale and laboratory-scale artificially constructed reed beds utilising the root zone method (RZM) of wastewater treatment were investigated for their removal efficiencies of a range of pathogenic microorganisms. Performances were compared for RZMs employing different hydrophytes, planting substrates and climatic conditions. All pathogens were removed by the RZM to some extent. Planted beds generally performed better than unplanted beds although the type of hydrophyte used was not significant. Gravel beds were more efficient than soil beds in the removal of protozoan pathogens and of helminth eggs; numbers of these pathogens were below levels of detection in gravel bed effluents. For faecal coliforms the type of planting substrate was not significant, providing hydrophytes were present. Climatic conditions made little difference to treatment efficiency although seasonal variation was observed in temperature climates, where the removal of faecal coliforms declined in the winter months, and in subtropical climates where higher numbers of free-living amoebae were recorded during the summer. It was concluded that the RZM is a suitable method for the treatment of domestic wastewaters in tropical and subtropical regions of Mexico.

scholarly journals Determine the Required Log Reductions of Human Intestinal Helminth Eggs by Waste Stabilization Pond: A Simulation for Wastewater Recycling in Agriculture

2019 ◽  
Vol 15 (1) ◽  
pp. 11-25
Author(s):  
Adel S. Faskol ◽  
Gabriel Racoviteanu
Keyword(s):  
Treatment Process ◽  
Hydraulic Retention Time ◽  
Climatic Conditions ◽  
Intestinal Helminth ◽  
Waste Stabilization Ponds ◽  
Waste Stabilization Pond ◽  
Helminth Eggs ◽  
Stabilization Ponds ◽  
Waste Stabilization ◽  
Wastewater Recycling

Abstract This paper investigates the determined the required log reductions for human intestinal helminth eggs by waste stabilization ponds as simulation as assessing of mitigating health risk to satisfy practice WHO, 2006 guidelines for the safe use of wastewater in agriculture (≤ 0.1 helminth egg/L) to protect the health of children under 15 years was the development of MATLAB, a computer program based waste stabilization ponds design based on parameter uncertainty and 10,000-trial Monte Carlo simulations were developed for a series of anaerobic, facultative and maturation ponds based on 95%-ile of effluent (≤ 0.1 helminth egg/L) which the result in a health-based target. Whereas the influent of the helminth eggs (Nematode) was (932.500 eggs/L). While the treatment provided (100 % reduction/removal) for the overall treatment process with total hydraulic retention time in climatic conditions of Libya it took 36.207 days in the anaerobic pond, facultative pond, first maturation pond and one of the subsequent maturation pond.

The Role of Protozoa in High Rate Wastewater Treatment Systems

1980 ◽  
Vol 15 (2) ◽  
pp. 187-201
Author(s):  
R. Booth ◽  
J.G. Henry ◽  
D. Prasad
Keyword(s):  
Wastewater Treatment ◽  
Hydraulic Retention Time ◽  
Mixed Population ◽  
High Rate ◽  
Ciliated Protozoa ◽  
Effluent Quality ◽  
The Poor ◽  
In Series ◽  
Wastewater Treatment Systems ◽  
Sludge Settleability

Abstract Three continuous, laboratory scale, high rate biological wastewater treatment systems operating in a similar mode were evaluated. The feed was a synthetic sewage with a COD and BOD of approximately 300 mg/l and 200 mg/l, respectively. The total hydraulic retention time in each system was 2-1/4 hours - 40 minutes aeration, 95 minutes sedimentation. The applied food to microorganism ratios (F/M) were equal to or greater than one. Systems I and II employed a single aerobic reactor whereas System III employed two aerobic reactors in series each with a hydraulic retention time of 20 minutes. Sludge was returned to the second reactor only, thus establishing dispersed growth in the first reactor and a mixed microbial population in the second. System I was strictly a bacterial system isolated from atmospheric contamination. System II employed a mixed population of ciliated protozoa and bacteria. Tests performed included soluble COD reduction, effluent, mixed liquor and return sludge suspended solids, SVI, pH, polysacharides, bacteria count, and protozoan count. Comparison of System I (bacterial) and System II (mixed population) revealed an improvement in effluent quality (SS, Total COD) as a result of the presence of ciliated protozoa. The higher effluent SS in System I was a result of the poor settleability of dispersed growth. Based on the knowledge of the effects of protozoa on dispersed growth, System III (bacterial reactor and mixed population reactor in series) was established to determine if such a series arrangement would further improve treatment efficiency. Several different two stage reactor system configurations were investigated including sedimentation after the first reactor with the effluent passing to the second reactor. Such an arrangement proved impractical due to the poor settleability of the dispersed growth associated with a predominantly bacterial system. System III resulted in a vast improvement in sludge settleability while maintaining an effluent quality equal to that of System II. This improvement in sludge settleability indicates improved system stability and reduced handling costs.

High-Rate Algae Ponds for Wastewater Treatment and Protein Production

1982 ◽  
Vol 14 (1-2) ◽  
pp. 439-452 ◽  
Author(s):  
G Shelef
Keyword(s):  
Wastewater Treatment ◽  
Protein Production ◽  
Chemical Separation ◽  
Climatic Conditions ◽  
High Rate ◽  
High Quality ◽  
High Rate Algal Ponds ◽  
Physico Chemical ◽  
Dry Biomass ◽  
Suspended Biomass

High-rate algal ponds (HRAP) under proper climatic conditions can produce annually over 150 tonnes of dry biomass per hectare of which 60 percent is photoautotrophic algae. This result in production of approximately 150 ton/ha-yr of oxygen, in addition 15 ton/ha-yr of nitrogen and 3 ton/ha-hr of phosphorus are removed by incorporation into the biomass which contain between 45 to 50 percent proteins. High quality effluent is produced following physico-chemical separation of the suspended biomass by alum flocculation and flotation.

Disinfection of sludge using lime stabilisation and pasteurisation in a small wastewater treatment plant

2004 ◽  
Vol 50 (1) ◽  
pp. 13-17 ◽  
Author(s):  
R. Keller ◽  
R.F. Passamani-Franca ◽  
S.T. Cassini ◽  
F.R. Goncalves
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Uasb Reactor ◽  
Faecal Coliforms ◽  
Lime Treatment ◽  
Physical Treatment ◽  
Helminth Eggs ◽  
In Series ◽  
Liquid And Solid Phases

Removal efficiency of faecal coliforms and helminth eggs was evaluated in a small wastewater treatment plant (WWTP) serving a population of 1,000. This system was formed by the association in series of a UASB reactor and four submerged aerated biofilters. The density of faecal coliforms and the count of helminth eggs were estimated in the liquid and solid phases of the system. Two different methods of disinfecting sludge were investigated: (a) chemical treatment with lime and (b) a physical treatment by pasteurisation. As expected, the association UASB + BF was very efficient at removal of helminth eggs from the final tertiary effluent, but coliforms were still present at high densities. Lime treatment and pasteurisation of sludge were very effective methods of disinfection and produced a sludge safe for final disposal.

scholarly journals Determination of kinetic parameters in a pilot scale BNR system treating municipal wastewater

2013 ◽  
Vol 8 (1) ◽  
pp. 68-74
Keyword(s):  
Wastewater Treatment ◽  
Carbon Source ◽  
Kinetic Parameters ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Biological Processes ◽  
Process Kinetics ◽  
Half Saturation Constant

Kinetics for the biological processes of nitrification, denitrification and carbon oxidation were studied in the aerobic and anoxic phases of a pilot scale Biological Nutrient Removal (BNR) plant treating municipal wastewater. The configuration of the treating system is based on the combination of the UCT (University of Cape Town) design and the step feeding process in a cascade denitrification. In order to study the process kinetics and to obtain reliable values for the investigated kinetic parameters batch experiments were performed. For this purpose, continuous feeding of the treating system was interrupted for a given period of time and the pilot plant was turned into a batch mode of operation. Thereafter, addition of NO3 --N and NH4 +-N into the anoxic and aerobic compartments of the treating plant, respectively, followed, whereas adequate initial concentration of a carbon source (municipal wastewater or synthetic substrate) was ensured in the mixed liquor. Experimental data indicated that the examined biological processes followed saturation kinetics. The maximum specific denitrification rate, qDN,max , was found to obtain values, depending on the type of the carbon source, between 0,045 and 0,390 gNO3 --N/(gXHET·d), whereas the extremely low value of the half saturation constant for the denitrification process (Km,NO3-N << 1mgN/l) indicated its description by zero order kinetics. The maximum specific nitrification rate, qN,max, was determined to vary in a narrow frame, between 1,28 and 1,60 gNH4 +- N/(gXAO·d). The half saturation constant for the nitrification process, Km,NH4-N, was estimated graphically at 3,1 – 6,1 gNH4 +-N l-1, corresponding to 62 – 122 μgNH3-N l-1. These values are considered to be in good agreement with the literature. The determination of kinetic parameters can be considered as a useful tool for the process design, operation and improvement of wastewater treatment plants. Furthermore, the study of the biological process kinetics contributes to the better understanding and outline of the complicated biological processes that contemporarily take place within the various phases of BNR wastewater treatment plants.

Antithrombin-mediated Inhibition of Factor Vlla-Tissue Factor Complex by the Synthetic Pentasaccharide Representing the Heparin Binding Site to Antithrombin

1996 ◽  
Vol 76 (01) ◽  
pp. 005-008 ◽  
Author(s):  
Jean Claude Lormeau ◽  
Jean Pascal Herault ◽  
Jean Marc Herbert
Keyword(s):  
Binding Site ◽  
Tissue Factor ◽  
Residual Activity ◽  
Coagulation Factors ◽  
Heparin Binding ◽  
Experimental Conditions ◽  
First Order ◽  
Heparin Binding Site ◽  
Coagulant Activity

SummaryWe examined the effect of the synthetic pentasaccharide representing the minimal binding site of heparin to antithrombin on the antithrombin-mediated inactivation of factor Vila bound to tissue factor. This effect was compared to the effect of unfractionated heparin. Using purified recombinant human coagulation factors and either a clotting or an amidolytic assay for the determination of the residual activity of factor Vila, we showed that the pentasaccharide was an efficient antithrombin-dependent inhibitor of the coagulant activity of tissue factor-factor Vila complex. In our experimental conditions, assuming a mean MW of 14,000 for heparin, the molar pseudo-first order rate constants for ATIII-mediated FVIIa inhibition by ATIII-binding heparin and by the synthetic pentasaccharide were found to be similar with respective values of 104,000 ± 10,500 min-1 and 112,000 ± 12,000 min-1 (mean ± s.e.m., n = 3)

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