The Applied Study Of Wastewater Treatment In Marine Culture By Filter-feeding Bivalves And Algae

It is very necessary to treat marine culture wastewater. It not only can guarantee the sustainable development of marine culture itself, but also can impact the cycle-utilization of ocean resources. Research status quo and treatment methods in culture wastuwater treatment are summarized in this paper. The method of filter-feeding bivalves filtration and macroalgae absorption is put forward, "his method is suit for China national conditions. The preliminary project device of the method is been done in this paper. In the mean time, the applied outlook of the method in the future is discussed.The main results and conclusions are as fellows:The absorption and removal rate cf nitrogen and phosphorus by microalgae : Chlorellasp, phaeodactylum tricornatum and isochrysis galbana are tested in this paper. The main conclusions are: (1) The amount of nutrient absorption of these three kinds of microalgae is different. The order of nitrogen absorption is: phaeodactylum tricornatum > isochrysisgalbana >chlorellasp. The order of phosphorus absorption is: phaeodactylum tricornatum >chlorellasp >isochrysis galbana. (2) The spot experiment of microalage to marine culture wastewater: at the experimental conditions, if there is no nutrient input, dissolved inorganic nitrogen (DIN) will be depleted within 0.056-0.344 day and dissolved inorganic phosphorus (DIP) will be depleted within 1. 115-3. 384 day.The experiment of removal nutrient by macroalgae: the experimental conditions are as fellows: the density of macroalgae is 5g/L; the culturewater is immobility; the experimental time is 24h. The main results are: the order of removal P04-P efficiency is: kelp(84. 4%) >ulvapertusa(8Q%) sarganin(61. 3%) > myurus algae(Z?>. 3%) ; The order of removal N02 - N efficiency is kelp/uJva pertusa(100%) > sarganin(35.7%) > myurus algae(33. 3%); The order of removal NH4- N efficiency is kelp/ulva pertusa(100%) >sarganin($&. 8%) >myurus a7gae(43%) ; The order of removal N03-N efficiency is kelp(83%) >ulvapertusadZ. 2%) >myurus algae(33. 6%) >sarganind3. 7%). Think about all aspects, kelp and ulva pertusa are chosen to further experiment.The removal nutrient experiment with different density of kelp and ulva pertusa: In the experiment, the density of ulva pertusa respectively is 0.5, 1, 2 and 4g/L; the density of kelp respectively is 2.5, 5, 7.5 and lOg/L. 2g/L ulva pertusa and 7. 5g/L kelp are testified to the best suitable density. In the certain experimental conditions, the efficiency of removal P04-P, N02-N, NH4-N and N03-N respectively is: 73.8%, 91.8%, 87.2% and 93.2% by 2g/L ulva pertusa. The efficiency of removal P04 -P, N02-N, NH4-N and N03-N respectively is: 70%, 57.5%, 86. 5% and 63.1% by 7. 5g/L kelp. 2g/L ulva pertusa and 7. 5g/L kelp are chosen to the next experiment.The experiment of removal total suspended solid (TSS) by filter-feeding bivalves: at the same experimental conditions, the order of removal TSS efficiency is oyster(93%) >scallp(88%) >calm(85%). The removal TSS efficiency of oyster is highest. Oyster is chosen to the next experiment.The treatment wastewater of marine culture by poly-culture of macroalgae and filter-feeding bivalves: at the certain experimental conditions, during 24h, the removal P04 -P, N02-N, NH4-N, N03 - N and TSS efficiency respectively is 62.6%, 55.7%, 46.0%, 56.6% and 84.5% bypoly-culture of kelp and oyster. The removal P04 - P, N02-N, NH.,-N, NO., -N and TSS efficiency respectively is 67.8%, 60.2%, 55.8%, 59.0% and 82. 5% by poly-culture of ulva pertusa and oyster.In accordance with the experimental conclusions, an preliminary treatment marine culture wastewater system is put forward: Natural sedimentation, filter-feeding bivalve? filtration and macroalgae absorption, macoralgae absorption again. Through these treatment stages, the effluent of marineculture will can te cycle-used.