Utilizing Sustainable Energy for Water Management in Semi-intensive Aquaculture Report

Transcription

1 Utilizing Sustainable Energy for Water Management in Semi-intensive Aquaculture Report Call For Report Call for final report Africa-Brazil Projects funded in the 2012/13 Report Status Submitted Title Utilizing Sustainable Energy for Water Management in Semi-intensive Aquaculture ID 411 Thematic Area Productivity Enhancing Technologies Reporting period 25 Jun Dec 2016 Co-leader Institutions National Agricultural Research Organisation & Embrapa Mid-North Project Co-leaders Mr. Lawrence Obeti & Mr. Luiz Guilherme Type of African Co-leader Institution NARO Summary The overall objective was to develop semi-intensive aquaculture production systems for peri-urban fish farmers. The specific objectives: (1). Carry out socioeconomic survey on the status of semi-intensive peri-urban fish farming. (2) Design and construct fish ponds/tanks utilizing small horsepower solar pumps for water recirculation. (3). Design and construct a wastewater (fish effluent) treatment facility utilizing indigenous vegetables (vegetable based bio-filter). (4). Assess fish effluent quality in vegetable based with respect to ammonia and nitrate. (5). Assess vegetable biomass development and safety for human consumption. Socio-economic status of semi-intensive peri-urban fish farming in the lake victoria basin Prototype of peri-urban fish tank and fish effluent treatment facility (vegetable based bio-filter) vegetable based bio-filter showed 93.4% and 99.3% ammonia and nitrate removal efficiency The levels of heavy metals obtained from the vegetables grown in the treatment facility were: Cadmium 0.2; Chromium not detected; Copper 14.6; Zinc 19.7; Lead 1.6 and Iron mg/kg Vegetable based bio-filter has higth potential to reduce ammonia and nitrate levels in fish effluent, with additional benefit from vegetables. However further ammonia removal beyond 93.4% requires use of aerators to increase dissolved oxygen levels and also applying agricultural lime in the effluent to keep the ph within the required range (7-8) for effective nitrification Country(ies) of Implementation Uganda and Brazil Project Results Socio-economic status of semi-intensive peri-urban fish farming. Key findings were: 51% farmers experienced water shortage of fresh water; 40% had poor water quality at the source; 95.3% did not treat wastewater (fish effluent) for recirculation and 87.2% farmers showed willingness to take up effluent treatment technology. Some of the key challenged experienced were: expensive feeds; poor feed management practices leading to high feed conversion ratios, poor quality fish seeds and low aquaculture extension service delivery affecting profit maximization of the enterprises Prototype of peri-urban fish tank and fish effluent treatment facility (vegetable based bio-filter) established. Ammonia levels in the vegetable based bio-filter were reduced significantly (p 0.05) beyond day 35..The levels of heavy metals obtained from the vegetables grown in the bio-filter were: Cadmium 0.2; Chromium not detected; Copper 14.6; Zinc 19.7; Lead 1.6 and Iron mg/kg. Iron and Lead levels were found higher than FAO/WHO safe limits of 425 and 0.3 mg/kg respectively. These high levels were absorbed from the underground water used for fish farming. One fish farmer and two neighboring households where the experiment was set were trained on construction, operation and maintenance of the treatment facility. One masters student capacity built by taking his masters research from the project..the growing of vegetables (collards) in soil less media as well as using them in treating fish effluent for recirculation was the innovative component in the study.. Scalability and replicability The proven fish effluent treatment technology could be scaled up using famer field school approach. This approach could involve setting up treatment technologies which would be used as a training material. Extension staff at local levels could be used to mobilize individual fish farmers and fish farmer communities to have hands on training at the established sites of treatment technologies. The key content of the training could include construction, operation and maintenance of vegetable based bio-filter and solar powered water recirculation system. This approach could enable fish farmers understand the entire system so as to own it, hence easy to scale up the technology

2 Impacts of project results The cost of drawing fresh water from urban water treatment system was significantly reduced by 61% since fish effluent could be treated using vegetable based bio-filter and recycled through solar powered recirculation pump. Enhancement of food security and nutrition all year round from the fish and vegetables grown in the treatment facility Sustainability of project The setup of the experiment to prove the concept of fish effluent treatment using vegetable based bio-filter was at a fish farmer s farm to enable the farmer own the technology and be a learning site to other farmers. The establishment of the vegetable based bio-filter and solar powered recirculating system was by using locally available materials e.g. wood, tarpaulin, gravel, solar panels etc. which could be cheaply obtained from the local markets Issues in project implementation Bureaucratic procurement process. NARO uses public procurement and disposal of assets Act of government which is lengthy (6-7 weeks), this caused delays in procurement of materials for constructing fish effluent treatment facility. Delay in the importation of water quality test equipment, Multi-Parameter Meter (DZB-712) and Ammonia nitrogen meter (DWS-296) by local equipment suppliers delayed the construction and performance assessment of the treatment technology. The high increase in prices of research equipment due to rise in exchange rates. Sudden death of fish or fish mortality in the fish tank due to feeding fish on contaminated feeds obtained from local open market by the fish farmer. This finally interrupted the objective to determine fish growth rate while using the treated water and energy demand by the solar pump when recirculating treated water Lessons Learned Vegetables (collards) have high potential to extract nitrogen for healthy growth from fish effluent after ammonia been converted into nitrate by nitrifying bacteria. Significant growth of vegetables in the treatment facility was achieved when algae concentration in fish effluent was yet low. High algae concentration in the effluent resulted into high competition for nutrients depriving vegetables of nutrients hence stunted growth. When the levels of heavy metals in the water to be used for fish farming higher than safe limits recommended by FAO/WHO for irrigation, the vegetables used in the treatment of fish effluent would absorb the metals. Such vegetables would be a health hazard to humans if consumed Suggestions for improvement In order to reduce the delay in the importation of water quality test equipment by local equipment suppliers, there is need to get direct links with the equipment manufacturers. There is great need to sensitize fish farmers about recognized feed manufacturing companies from which safe feeds without any contamination by aflatoxin and other toxic foreign matter could be obtained Publications A scientific paper titled Assessment of performance of vegetable based bio-filtration system for treating fish effluent for reuse in peri-urban areas is at the last stage of refinement for publication. High levels of ammonia (>0.3 mg/l) in fish tanks/ponds renders water toxic to fish, thus limiting reuse of fish effluent. Periurban fish farms with limited access to fresh natural water bodies draw water from urban water supply system which is costly. The main objective was to assess performance of vegetable based bio-filter in reducing ammonia levels in fish effluent for reuse. specific objectives: (1) to assess fish effluent quality along biofilter length with respect to ammonia and nitrate and (2) to assess vegetable biomass development and safety for human consumption. Ammonia and nitrate levels were measured using LaMotte reagent kits. Vegetable biomass development determined by measuring plant height and counting number of leaves. Measurements were taken in the field to minimize errors.the levels heavy metals in vegetables were measured using Atomic absorption spectrophotometer. prototype of vegetable based bio-filter for reducing ammonia and nitrate levels in the fish effluent for reuse. Significant reductions in ammonia and nitrate levels were obtained in the vegetable based bio-filter. This resulted into 93.4% (ammonia) and 99.3% (nitrate) removal efficiency at the exit. Significant increase in the vegetable height and number of leaves observed over the first 35 days. The levels of Cadmium (not detected), Chromium (not detected), Copper (14.6), and Zinc (19.7) mg/kg were below FAO/WHO safe limits. except Lead (1.6) and Iron (1631.8) mg/kg which had higher levels than FAO/WHO safe levels of 0.3 and 425 mg/kg respectively. these high levels were absorbed from the underground dug well used for fish farming. Vegetable based bio-filter has high potential to reduce ammonia and nitrate levels in fish effluent, with additional benefit from vegetables

3 Quantitative Project Results Quantitative - Project Results Knowledge Generated (A relevant discovery or new information made by the project) Technologies (Innovation developed through the application of information in the design, production, utilization of goods and services) Products (Usage of technology, goods, method or information transformed into an object or tool) Services (Use of a specific technology or a product to favor a community) Key Project Outputs Appropriate size of vegetable based bio-filtration system for treating fish effluent in periurban areas is 3:1 (length to width ratio). Performance of vegetable based bio-filttration is 93.4% ammonia removal and 99.3% nitrate removal Vegetable based biofiltration system Treated water from fish effluent. Fresh vegetables produced (2.3kg/square meter area) from the treatment technology. Reduced costs of drawing fresh water from urban water supply. Environmental degradation due to open disposal of fish effluent minimized. Vegetables are source of food/income for the fish farmer. Name Country/City Number of Days Gender Technical visit to Embrapa mid north by Obeti Grism Lawrence (co-leader) where knowledge and skills obtained on fish farming integrated with poultry, crops and animals (called systemiah) Brazil-Embrapa mid north 6 male Individual Training and Technical Visits Technical visit to Uganda- NARO by Luiz Carlos Guilharme (co-leader) to carry out technical evaluation of project activities and provide technical back-up service on the project implementation Uganda-Kampala 8 male The fish farmer (Mr. Kamulegaya Wilfred) where the project experiment was set was trained on construction, operation and maintenance of vegetable based bio-filtration system. Uganda-Kampala 4 male Events Organized Germplasm Exchange (Living genetic w w w w Event Name Country/City Event Type (workshop, forum, symposium, etc.) Number of participants/people trainned x x x x y y y y z z z z w w w w Species Number of Accessions Recipient Country x x x

4 resources: seeds, tissue, etc, that is maintained for the purpose of animal and plant breeding, preservation, and other research uses) Number of Participating Professionals (in the project team as a whole - Foreing instuition and Embrapa center) y y y z z z w w w Female Male 2 12

5 Attachments (photos and other documents)