scholarly journals METALS, NUTRIENTS AND COD REMOVAL BY FRESH AND MARINE WATER ALGAE (SEA WEEDS)

Keyword(s):  
2010 ◽  
Vol 13 (3) ◽  
pp. 92-102
Author(s):  
Trung Duc Le

The industrial production of ethanol by fermentation using molasses as main material that generates large quantity of wastewater. This wastewater contains high levels of colour and chemical oxygen demand (COD), that may causes serious environmental pollution. Most available treatment processes in Vietnam rely on biological methods, which often fail to treat waste water up to discharge standard. As always, it was reported that quality of treated wastewater could not meet Vietnameses discharge standard. So, it is necessary to improve the treatment efficiency of whole technological process and therefore, supplemental physico-chemical treatment step before biodegradation stage should be the appropriate choice. This study was carried out to assess the effect of coagulation process on decolourization and COD removal in molasses-based ethanol production wastewater using inorganic coaglutant under laboratory conditions. The experimental results showed that the reductions of COD and colour with the utilization of Al2(SO4)3 at pH 9.5 were 83% and 70%, respectively. Mixture FeSO4 – Al2(SO4)3 at pH 8.5 reduced 82% of colour and 70% of COD. With the addition of Polyacrylamide (PAM), the reduction efficiencies of colour, COD and turbidity by FeSO4 – Al2(SO4)3 were 87%, 73.1% and 94.1% correspondingly. It was indicated that PAM significantly reduced the turbidity of wastewater, however it virtually did not increase the efficiencies of colour and COD reduction. Furthermore, the coagulation processes using PAM usually produces a mount of sludge which is hard to be deposited.


Author(s):  
SHANKAR B. UMA ◽  
Lakshmi Chandana M.V.V. ◽  
SRIDEVI V ◽  
LAKSHMI L. NEELIMA CHANDRA ◽  
◽  
...  

Author(s):  
Katya Peycheva ◽  
Katya Peycheva ◽  
Mona Stancheva ◽  
Mona Stancheva ◽  
Stanislava Georgieva ◽  
...  

In this study, the ecosystem marine water-sediment-biota was investigated and the pollution was assessed. The concentrations of eight elements were determined in marine water, sediments and four fish species collected from Black Sea (Varna), Bulgaria during 2013. Marine water recorded the highest concentrations of Zn (15-22 μg/L), As (1.1–1.2 μg/L) and Pb (0.7-0.8 μg/L) while Zn (31-52 μg/g), Pb (21-29 μg/g) and Cu (20-34 μg/g) and show the highest concentrations in sediments. Water and sediments showed similar spatial distribution patterns for the highest mean values of the different metals. In the analysed fish species, the highest concentration of the metals Cu and Zn were found in Trachurus Mediterrneus (0.42 mg/kg w.w) and in Sprattus Sprattus (12.7 mg/kg w.w), respectively while the heavy metals As and Hg were found with maximum values in Pseta Maxima (3.99 mg/kg w.w and 0.08 mg/kg w.w respectively). The results from this study were compared with our data for a previous period (2004-2006) and they show decrease in the levels of heavy metal.


1991 ◽  
Vol 23 (7-9) ◽  
pp. 1503-1507 ◽  
Author(s):  
L. M. Triet ◽  
N. T. Viet ◽  
T. V. Thinh ◽  
H. D. Cuong ◽  
J. C. L. van Buuren

The effluent from activated sludge treatment of petroleum wastewater was treated with the aid of a ponding system using aquatic plants (Water Hyacinth, Chlorella, Reed). A good result was obtained in this study. Pilot pond system shows that the purification efficiency depends on the residence time of about 14 days. The petroleum removal waa 97-98 %, the COD removal was from 88-93 %. The dissolved oxygen amount (with Chlorella) increased from 0.7 mg/l to 9.8 mg/l and the pH increased from 6.9 to 8-8.6. The application of 3 step biological pond with the use of Water Hyacinth, Chlorella, Reeds for post treatment of petroleum wastewater is appropriate in Vietnam.


1990 ◽  
Vol 22 (7-8) ◽  
pp. 153-160 ◽  
Author(s):  
Pradeep Kumar ◽  
R. J. Garde

With increasing stress on existing wastewater treatment systems, it is necessary either to upgrade the treatment unit(s) or install an entirely new treatment plant. Obviously, the upgrading is preferred over the alternative of having a new system. Keeping this in view, in the present project, an attempt has been made to explore the possibility of upgrading existing facultative ponds using water hyacinth. Bench-scale batch studies were designed to compare the performance of hyacinth treatment system with facultative ponds. Investigations were carried out with synthetic wastewater having COD in the range of 32.5-1090 mg/l. The efficiency of COD removal in water hyacinth ponds was 15-20 percent more than the facultative ponds. Based on the results, an empirical model has been proposed for COD removal kinetics. In the second phase of the project a hyacinth pond was continuously operated. BOD, COD, TS, TN, TP, pH, and DO were regularly monitored. However, the DO of the effluent from hyacinth treatment system was considerably reduced. Effluent should be aerated before it is discharged. The results indicate that the existing facultative ponds can be stalked with water hyacinth to improve their performance as well as hyacinth treatment systems can be installed to support the conventional treatment.


1987 ◽  
Vol 19 (12) ◽  
pp. 79-83
Author(s):  
K. Bartoszewski ◽  
A. Bilyk

Rettery wastewaters were treated in anaerobic and aerobic ponds. Anaerobic treatment yielded efficiencies of BOD5 and COD removal as low as 20%. The treatment process conducted under aerobic conditions in aerated and stabilizing ponds arranged in series took from 18 to 20 days and gave efficiencies of BOD5 and COD removal amounting to 90%. The experimental results were interpreted by virtue of the Eckenfelder equation. Excess activated sludge was subjected to aerobic stabilization in a separate tank. A new technology was suggested for the existing obsolete industrial treatment plant.


1995 ◽  
Vol 31 (9) ◽  
pp. 101-107 ◽  
Author(s):  
Chongchin Polprasert ◽  
Charles N. Haas

Anaerobic reactors were operated in a semi-batch mode and fed with the dual substrates glucose (G) plus acetic acid (Ac) as primary organic sources to study the effect of sulfate on COD oxidation. With glucose, COD removal by methane formation was seriously inhibited, resulting in COD accumulation in the reactor. Although acetic acid can be consumed by some sulfate-reducing species, it was not a major substrate for sulfate reduction, but was largely responsible for methane formation in the anaerobic mixed culture used in this study. With dual substrates, extreme inhibition of methanogenesis did not occur as did with glucose alone. Instead, methanogens were found to work in harmony with acid formers as well as sulfate reducers to oxidise COD. Interestingly, from 12-hour monitoring, increased G/Ac COD ratios decreased COD removal rates as well as biogas production, but resulted in higher sulfate reduction. This suggests that there should be an optimal feed G/Ac COD ratio, for which removal of both organics could be maximised.


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