The constructed closed recycling system discussed in this report will be economically viable in future for the production of fish and vegetable in earth, space station and space colony, further, it will contribute a lot in prevention of pollution in the world's ecological system.
Using the equations, the expected nutrient characteristics of waste water were determined and it was found that the resulting nutrient balance was almost same as that in hydroculture solution when KOH was added to maintain pH level. However the resulting concentration of nutrient was quite low for plant production. This problem was solved by using reverse osmosis (RO) system whereby the low concentration of waste water was made higher by separation. The advantage of RO system are low energy cost, simple equipment, no effect composition of water components. After testing five separation membranes, the permeated water rate of SU-710 was larger than SC-3100, hence it was found that SU-710 membrane was the best for this waste water. By using reverse osmosis four levels of concentration were produced from fish waste water and used plant growing experiment, it was found that plant grow well at a level about above EC1.6 sector. This plant consumption of ions were measured during the growth period.
RO system could combine fish and plant production through the advantageous use of separated high concentration water for plant and permeated water for fish in the integrated combined system.
