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Technology and Engineering
- ISSN: 2333-2581
- Modern Environmental Science and Engineering
Effective Removal of Nitrogen and Phosphorus from SalineSewage by Dunaliella tertiolecta through Acclimated Cultivation
Kam-Chau Wu, Kin-Chung Ho and Yiu-Hung Yau
Centerfor Research in Envirnomental Science, The Open University of Hong Kong, Hong Kong, China
Abstract: Conventional activated sludge processes used for biological treatment of saline sewage usually have low removal of nutrient especially at high salt concentrations. In meanwhile, saline sewage provides an opportunity for applying microalgal based sewage treatment by marine algal species. D. tertiolecta isolated from algal blooming sample in local costal water was grown in non-sterile saline and nutrient rich sewage effluent for a bioremediation study. To promote better growth and nutrient removal of D. tertiolecta in saline preliminary effluent (PE), acclimated cultivation was also investigated in this study. With high nutrient removal efficiencies (i.e., orthophosphate, nitrate-nitrogen and ammonia-nitrogen), overall removal percentage of acclimated D. tertiolecta in PE was above 65% after 8d. The performance was relatively good concerning orthophosphate, which reached 70% ±13.5% after 6d and 80±1.3% after 8d. With respect to nitrogen sources, the removal of nitrate reached 60 ±5.4% after 6d and 74±0.1% after 8d. The performance of acclimated cultures was improved significantly in comparison to un-acclimated cultures. Overall, acclimated D. tertiolecta was successfully cultivated in unsterilized saline PE. While having a high potential for nutrient removal (particularly for orthophosphate and nitrate) from sewage, microalgal sewage treatment is also believed to a useful tool for biomass production.
Key words: algal biomass, acclimated cultivation, Dunaliella tertiolecta, nutrient removal, saline sewage
