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sewage and wastewater treatment

Chlorococcum humicola, Chlorella conglomerata, Chroococcus turgidus and Desmococcus olivaceus were inoculated into sewage samples collected from coovum river at Koyambedu, Chennai. Growth and biochemical composition of micro algae and physico- chemical parameters of sewage samples were monitored. There was a significant reduction in major physico chemical parameters of sewage. Bio-diesel potentials of algal biomass produced were also determined. Chlorella sp grew very well followed by Desmococcus sp.

The results obtained for certain critical parameters which indicate the level of pollution such as total solids, total dissolved solids, total suspended solids, electrical conductivity, calcium, magnesium, sodium, potassium, iron, BOD,COD,nitrogen, phosphorus  and heavy metals cobalt  and chromium have shown a significant reduction after Phycoremediation, for  both the treatment methodologies employed. Figure 1 Depicts the results of the Algae treated sewage method showing a significant reduction in Total suspended solids ( 90% on average).
Total hardness, Ca, Mg, Na and K:
Algae grown sewage showed a better reduction in total hardness than algae treated sewage. There was 65 to 75 % reduction in total hardness in algae grown sewage (Fig 4 and 5). Both the treatment  methodologies  resulted in a reduction in Ca, Mg, Na and K. (Figures  6, 7 and 8).
Fig 9 shows that there is a significant reduction in chlorides (70 to 95 %) by the Algae treated sewage method. Figure 10 shows an appreciable reduction in the iron  content with all the species employed. Figures 11 and 12 show that both the treatment methodologies have shown an excellent reduction in  BOD and COD (90 to 95 % on an average). Algal treatment also resulted in a significant removal of nitrogen and phosphates (70 to 90%). The Algae Grown Sewage method is effective in reduction of nitrogen content of the sewage  as shown in figure 13.
An appreciable reduction in phosphate and nitrate after subjecting to phycoremediation, by the Algae treated Sewage Method is represented in figures 14 and 15. Figure 16 has shown that heavy metals such as Co and Cr were removed effectively by micro algae from sewage ( 50 to 95% on an average).
Figure 20 shows the increase in the fatty acid content of the Chlorococcum sp , which is converted to fatty acid methyl ester in order to prove its  fuel potentiality, as well evidenced during stress condition for the microalgal species by various researchers(Chisti, 1981; Nagle and Lemke, 1990; Sawayama et al., 1995). Figure 18 shows that there had been the removal of oil and grease by algal treatment (70 to 90 % on an average)



Fig.1 Algae grown Sewage  Method (TS,TDS,TSS)

Fig.2 Algae treated Sewage Method (TS,TDS,EC)


Fig.3 Algae treated Sewage Method (TSS)

Fig.4 Algae grown Sewage  Method (Total Hardness)


Fig.5 Algae treated Sewage Method  (Total Hardness)

Fig.6 Algae treated Sewage Method

Fig.7 Algae grown Sewage  Method

Fig.8 Algae treated Sewage Method

Fig.9 Algae grown Sewage  Method

Fig.10 Algae treated Sewage Method

Fig.11 Algae grown Sewage  Method

Fig.12 Algae treated Sewage Method

Fig.13 Algae grown Sewage  Method

Fig.14 Algae treated Sewage Method

Fig.15 Algae treated Sewage Method

Fig.16 Algae grown Sewage  Method


Fig.17 Algae treated Sewage Method

Fig.18 Algae grown Sewage  Method


Fig.19 Algae treated Sewage Method

Fig 20. Changes in Fatty acid methyl esters before and after Phycoremediation (FAME %) by Algae treated Sewage Method

Conclusion
From the current study it is evident that the following species Chlorococcum humicola, Chlorella conglomerata, Chroococcus turgidus and Desmococcus olivaceus have an effective phycoremediation potential and  their biomass can be used to explore their biofuel potentiality which requires future research. The present investigation reports successful treatment of sewage from Coovum river, at  Koyambedu, Chennai using certain selected micro algae and a simultaneous  possibility of using biomass generated as a potential source of biodiesel.

Benefits of Phycoremediation

The following are the benefits of Phycoremediation:
1. Phycoremediation is a cost- effective, ecofriendly and a safe process.
2. The micro algae employed are non-pathogenic photosynthetic organisms and they do not produce any toxic substances.
3. Phycoremediation effectively reduces nutrient load thereby reducing TDS.
4. Phycoremediation reduces sludge formation to a very large extent.
5. Phycoremediation increases dissolved oxygen levels thorough photosynthetic activity.
6. Phycoremediation keeps bacterial population under control.
7. Algal growth in the effluent also removes waste CO2 from air there by contributing to the reduction of green house gases.
8. The algal biomass has high nutrient value and can be suitable as a live feed for aquaculture.
9. The algal biomass could also be used as a Bio-fertilizer and in EM (Effective Microbes) preparations.
10. Conventional chemical treatment of effluents results in concentrating the toxic waste in the form of sludge and requires landfill. Whereas
phycoremediation detoxifies and removes it for ever
11. Minimal odour compared to conventional methods of treatment.
12. Simple operation and maintenance
13. Construction and Operation Costs are typically less than half those of mechanical treatment plants (e.g. activated sludge, sequencing batch
reactors)
14. Sustainable treatment solution with significant potential for energy and nutrient recovery.

Industrial projects

Dr V Sivasubramanian and his team has implemented algae based treatment technology in industries in India and abroad. pH correction, sludge reduction/removal, BOD and COD reduction have been achieved through Phycoremediation. MORE 

 
 

WORLD'S FIRST PHYCOREMEDIATION PLANT

World's First Phycoremediation plant: Dr V Sivasubramanian, has set up the First Phycoremediation plant at SNAP Industry. Algal remediation technology helps in pH correction of the acidic effluent and complete reduction of sludge formation. SNAP is now a zero disposal company. The phycoremediation plant has been in operation from September 2006. The effluent generated by the industry is highly acidic and of very high TDS (40000 mg/L). The entire effluent is evaporated using slope tank with zero sludge formation. The algal biomass produced is used in Biofertilizer preparation and sold by the Company. .......(.more )

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Contact Us

For consultancy on algae based remediation, bio-fuels and CO2 mitigation and algal biomass production

Dr V Sivasubramanian, Director

Phyco Spectrum, 132 (52 A) A K Block, 7th Main road, (click here for location map), Anna Nagar, Chennai 600040, India. Email to: vsivasubramanian@gmail.com. Phone: 91 044 42122699. Mobile: 91 9677144453 ;

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