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14. 16:00 16 :15 Phan Công Hoàng, Lê Bảo & Hoàng Tùng
MH2 MH3A MH3B
■ : :W Wmit
Methanosarcina sp .->
tethanosarcina sp
Methanosarcina sp.
Hình 2. Phán tích thành phần methanogen trong các mô hình thí nghiệm bằng phương pháp điện di biến tính gen 16S rDNA (DGGE)
Rong biển Ulva sp. cùng với bùn đáy đầm nuôi tôm và chất thải chăn nuôi được dùng làm nguồn cơ chất cho quá trình
lẽn men kỵ khí sinh methane ở điều kiện nước mặn. Quá trình phân hủy diễn ra tích cực ở môi trường có hàm lượng
muối 1 7 % 0 nhưng rất kém ờ 26 %0. Sau 90 ngày, trên 98% COD đã được loại vả thành phần methane trong tổng thể tích
khí tạo thành đạt mức cao nhất là 81,8% trong mô hình có bổ sung Na-molybdate (1 mM) để ức chế vi khuẩn khử sulfate. Phân tích thành phần methanogen trong các mô hình bằng phương pháp điện di biến tính (DGGE) gen 16S
rDNA cho thấy Methanosarcina spp. đóng vai trò chủ đạo cho quá trình sinh methane ờ đây. Kết quả thu được trong
nghiên cứu này là cơ sờ để phát triển công nghệ biogas sử dụng rong biển kết hợp xử lý chất thải hữu cơ để tận thu năng lượng, góp phần giải quyết vấn đề ô nhiễm đồng thời tạo thêm nguồn năng lượng cho các vùng ven biển và hải đảo.
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ENERGY RETRIEVAL FROM ORGARIC WASTES VIA ANAEROBIC DIGESTION IN SALTWATER CONDITIONS
Nẹuyen Thu Hoai1, Duong Chi Cong2, Dinh Thuy Hang2
Vietnam-Russia Tropical Center, Vietnam Defence Ministry
2Institute of Microbiology and Biotechnology - Vietnam National University, Hanoi
SUMMARY
Organic contamination along coastal lines in Vietnam is of concern for the scientific community. Anaerobic fermentation with
methane production has been proven as an effective technology for the treatment of organic wastes. In Vietnam, biogas technology
presently has not yet been demonstrated with variable organic substrates, as well has not been efficiently operated under salt water condition where the digestion processes generally are not active.Jn the present study, anaerobic fermentation was established in the
laboratory models using seaweed U l v a sp. in co-digestion with some other organic wastes such as shrimp pond sludge and waste from a pig farm as organic substrates. The models were operated under salt water condition, using natural seawater from Nhatrang
and Catba. The obtained results showed that the anaerobic fermentation was active at the salinity of 17 %0 NaCI (seawater from
Catba). The process was more efficient when shrimp pond sludge and pig farm waste were co-digested with the seaweed. After 60 day operation, more than 60% o f the soluble COD was removed and after 90 days, almost all (over 98%) COD was removed. To
minimize the competition of sulfate reducing bacteria (SRB) in the seawater environment, sodium molybdate (I mM) was added in one experimental model and as the result, the methane ratio in the produced gas increased from 51.8% to 81.8%. Analyses of
m e l h a n o g e n s in the experimental models by using PCR-DGGE for the 16S rDNA gene showed that Methanosarcina spp. were the key methanogens in the models. This study would provide neccesary informations for the development o f biogas technology in the treatment oi'organic wastes with energy retrieval, giving a solution for the pollution problems in shoreline and island areas.