BIOFILM START-UP ON DIFFERENT FILTER MEDIA Min Jiang, Weiwei Miao, Chunfang Luo Shanghai Ocean University 10-Jan-16

AquaFish CRSP USAID Travel funding for this presentation was provided by AquaFish Collaborative Research Support Program The Aquaculture CRSP is funded in part by United States Agency for International Development (USAID) Grant No. EPP-A The opinions expressed herein are those of the authors and do not necessarily reflect the views of the US Agency for International Development.

Introduction Materials and methods Results and discussion Conclusions

Filter media Introduction Aquaculture industry Environmentally friendly technologies Recirculating system Water quality diseases Environmental impacts Bio-filter system

Materials and methods Aquaculture waste water

pH8.12 TAN-N (mg/L)32.95 NO 2 -N (mg/L)6.69 NO 3 -N (mg/L)2.81 PO 4 -P (mg/L)5.60 COD Mn (mg/L)82.37 Alk (mmol/L)2.62 H T (mmol/L)4.92 General conditions of the recirculating system Volume of Waste water: 10L Volume of Filter: 220mL Velocity of flow: 63.3L/h DO: 7.5±0.23mg/L Water quality of the initial aquaculture waste water for biofilm start-up

Bio-fiber fill Netlike plastic fillplastic ball coral sandporcelain ring Five kinds of filter media

During the first 108h, water samples for quality analyses were collected from the tank every 12h. (8:30 & 20:30) After that, samples were collected every 24h. (8:30) The whole experiment lasted for 22days. pH Environmental quality standards for surface water GB 3838—2002 People’s Republic of China TAN-N NO 2 -N NO 3 -N PO 4 -P COD Mn Alk HTHT

Results and discussion Nitrite increased corresponding to the rapidly decreasing of TAN during the first phase of start-up and kept growing up for 6 days after TAN had reached a steadily low level. While nitrate increased during all the experimental period. Concentrations of TAN, NO 2 -N and NO 3 -N in the biofilter with coral sand media changed regularly.

Same situation happened in biofilters with the other four media while the days needed to reach the stable low concentration of NO 2 -N were different.

During the start-up period, coral sand media showed the best efficiency of turning TAN to NO 2 -N and then NO 3 -N. NO 2 -N was less than 1.0 mg/L after 12 days. Netlike plastic fill and porcelain ring were the worst. The intervenient were plastic ball and bio-fibre fill. Bio-fiber Netlike plastic plastic ball coral sand porcelain ring

pH and Total alkalinity decreased rapidly during first several days and then increased slowly to stable values. The biofilter with coral sand media had higher pH and alkalinity than others.

Hardness in five filters nearly doubled after 22 days. Hardness in filters with coral sand, bio-fibre fill and porcelain ring were higher than the other two.

Phosphate-P was consumed. Biofilters with coral sand and porcelain ring had less phosphate-P than others.

Different ability of COD removal was approved in 5 biofilters.

conclusions Change of water quality: regularity Biofilm start-up: coral sand media> plastic ball≈ bio-fibre fill > Netlike ≈ porcelain ring Advantage (1)Biofilm forming rapidly (2)Alkalinity and pH buffer (3)Higher consumption of phosphate (4)Relatively higher COD removal Disadvantage (1)Increasing hardness (2)Heavy coral sand

Thanks for your attention