APPLICATION OF WATER RECIRCULATING TECHNIQUES IN AQUACULTURE Pham Thanh Liem College of Aquaculture and Fisheries, Can Tho University 1 Content 1. Aquaculture systems 2. Waste creation in culture system 3. Introduction about Recirculating Aquaculture System (RAS) in aquaculture 5. Operation of Recirculating Aquaculture System (RAS) 2 1
1. Aquaculture systems Integrated Aquaculture Fish/ Shrimp (Freshwater Prawn, Black Tiger Shrimp) Rice Shrimp Forest Fish/ Shrimp in garden canal 3 In tanks 1. Aquaculture systems Snakehead culture in plastic lining tank Walking catfish, swamp eel culture Ell, white leg shrimp culture 4 2
1. Aquaculture systems Cage culture Rivers: tilapia, common carp, catfish, mastacembelidae. Sea: cobia, Barramundi, black pomfret. 5 1. Aquaculture systems Intensive culture in ponds Freshwater: catfish, snakehead, climbing perch, giant freshwater prawn Brackish water, marine: black tiger shrimp, white leg shrimp, Barramundi, Pseudapocryptes elongatus. 6 3
1. Aquaculture systems 120000 100000 Diện tích (ha) 80000 60000 40000 20000 0 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Fluctuation of aquaculture area in the Mekong Delta 7 2. Waste Origin O 2 ENVIRONMENT D M G Leftovers Excretion and Respiration Defecation D: Digestion; M: Metabolism; G: Growth 8 4
2. Waste Origin Food Absorption Digestion Metabolism Leftovers Defecation (Fecal Loss) Excretion (Non-Fecal Loss) Respiration CO 2 Growth 9 2. Waste Origin Food (100%) Nitrogen Accumulation (21-30%) Suspended (15-30%) Dissolved (49-60%)? Releasing from the bottom Settlement 10 5
3. Introduction about RAS General principles Water in tanks is cleaned continuity and reused (more than 90%) Removing suspended matter following by mechanical principle Providing oxygen Removing dissolved organic matter by heterotrophic bacteria Removing nitrate and phosphate by plants or anti nitrate bacteria 11 The components of the system 1. Culture tank 2. TSS removable tank 3. Holding tank 4. Biological filter tank 5. Overflowing tank 6. Weed tank 7. Periphyton tank 8. Anti nitrate tank Basic Recirculating Aquaculture System has 5 main components (1-5). 12 6
The components of the system Basic RAS combining with anti nitrate tank 13 The components of the system Basic RAS combining with weed tank or aquaponics 14 7
The components of the system 15 1. Nursing with aquatic species: fish, crustacean. 16 8
Recirculating filter in black tiger shrimp larvae nursery (VN) 17 Recirculating in Clarias hatchery 18 9
2. Growout stage with aquatic species: fish, crustacean and others. 19 African catfish culture system (Yield 500 kg/m 3 /crop) 20 10
Eel Recirculating Culture System 21 Lọc trống Pseudorhombus arsius culture system 22 11
Salmon culture system 23 Tilapia culture system (140 kg/m 3 /crop) 24 12
Biological filter Fecal settlement Culture tank Experimental striped catfish culture system in RIA2 2 25 Experimental system in College of Aquaculture and Fisheries - CTU 26 13
3. Broodstock culture and domestication with other aquatic speices: fish, crustacean or others. 27 Bể nuôi tôm Bể lọc sinh học (chìm) Hệ thống sục khí kéo nước Domestic black tiger shrimp culture system (RIA2) 28 14
Benefit 1) Occupying less space 2) High yield, 3) Less water consumed than normal culture, 4) Biological safety, 5) No environmental pollution, 6) High quality product 29 Results of RAS Species Aquaculture system Water usage (L/kg) Yield (kg/m3/crop) Tilapia O.niloticus pond 21.000 17.4 Salmon S.gairdneri Race-way 9.000 60 Penaeid pond 11.000-21.340 4,2 11 Tilapia O.niloticus RAS 100 134 Tilapia RAS 90-120 Tilapia RAS 25 500 Striped catfish pond (4 m) 7.400 10,55 Striped catfish RAS (ao) (2.2m) 544 40 Snakehead RAS 55 144 30 15
Difficulties 1. High cost for basic building 2. High technique requirment 31 5. Operation of culture system Water quality of trout culture pond (trout) Parameters Unit Content Dissolved oxygen mg/l >7 Temperature o C 14-16 ph 6,5-7,5 Amonia NH 3 mg/l <0,01 Nitrit NO - 2 mg/l <0,2 Nitrate NO - 3 mg/l <200 Nitrogen N 2 % <100 CO 2 mg/l <15 Oxygen consumed kg/kg feed 0,4 CO 2 created kg/kg feed 0,56 Source : Coppens International BV 32 16
5. Operation of culture system Water quality of tilapia culture pond Parameters Unit Content Dissolved oxygen mg/l >6 Temperature o C 27-28 ph 7-8 TAN mg/l <5 NH 3 mg/l <0,5 Nitrit NO 2 -N mg/l <5 Nitrate NO 3 -N mg/l <100 Alkalinity mg CaCO 3 /L >150 Cloride mg/l 100 (NaCl) or 250 (CaCl 2 ) Hardness mg CaCO 3 /L >50 Source: Drennan and Malone, 1992 33 5. Operation of culture system Water quality of Striped Catfish culture pond Parameters Unit Content Dissolved oxygen mg/l >2 Temperature o C 26-33 TSS mg/l <100 ph 7-7,5 TAN mg/l <10 Nitrit NO 2 mg/l <5 Nitrate NO 3 mg/l <100 CO 2 mg/l <35 Alkalinity mg CaCO 3 /L >50 Hardness mg CaCO 3 /L >50 Nguồn: Nguyễn Nhứt, 2014 34 17
5. Operation of culture system 1. Activating System Stimulating nitrafication bacteria (Nitrosomonas and Nitrobacter), in 15-21 days. Bacteria source: Bacteria cultured from biological products (10-15 days) Nature development of bacteria in 21-28 days Fertilizing with 10-15 mg NH 4 Cl/L and 5-7 mg NaNO 2 /L Stocking fish when TAN redox ability of biological filter is equal total TAN created from everyday feed 35 5. Operation of culture system 2. System management Water quality parameters need to be followed regularly are O 2, temperature, ph, NH 3, NO 2-, NO 3-, CO 2 and alkalinity. If: Oxygen <2: increasing aeration, water exchange, increasing water filter speed, dividing amount of feed Temperature <26 o C: decreasing feed TSS>100 mg/l: exchanging water 20-30%/ day, dividing amount of feed, increasing water amount to sediment pond, releasing sediment bottom 36 18
5. Operation of culture system 2. Quản lý hệ thống ph <7: sử dụng vôi CaCO 3, NaHCO 3 để nâng ph; ph>7,5: thay nước TAN>10 mg/l: thay nước 20-30%, tăng xả cặn đáy và giảm chất lơ lững CO 2 >20mg/L: Tăng sục khí, tăng lượng nước qua lọc nhỏ giọt, hoặc phun nước Kiềm<50 mg/l: sử dụng vôi CaCO 3, NaHCO 3 NO 2 >5 mg/l: sử dụng NaCl (gấp 20 lần NO 2 ) 37 5. Operation of culture system 2. System management Fish health management: No stock disease fish, using fish from our hatchery. Fingerling: quarantine, checked before stocking Tap water or well water need to be sterilized. 38 19
5. Operation of culture system 2. System management Feed management: Feed by machine, feed as demand or manually. Combining feed by machine and manual to prevend overfeeding. 39 Recirculating tank in CTU Culture tank Filter tank Filter cultch 40 20
Experimental system Inside Recirculating Aquaculture System in CAF Lọc nhỏ giọt Lọc sinh học Đèn UV Bể nuôi 41 THANK YOU FOR YOUR LISTENING 42 21