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A SERIES OF TRIALS WAS THEREFORE UNDERTAKEN, USING TIL:: A COMMON POND FISH, AS THE EXPERIMENTAL SPECIES.
CHOSEN FOR ITS HARDINESS AND ABILITY TO THRIVE IN ADVERSE ENVIRONMENTS, THE TILAPIA IS CAPABLE OF UTILISING THE PLANKTON IN THE TREATED SEWAGE AS A MAIN FOOD SOURCE.
THE TRIAL WAS EXTENDED OVER A PERIOD OF 190 DAYS WITH TILAPIAS CULTURED IN TWO OXIDATION PONDS -- ONE RECEIVING SECONDARY EFFLUENTS FROM THE ACTIVATED SLUDGE SYSTEM WHILE THE OTHER RECEIVED A MIXTURE OF SECONDARY EFFLUENTS FROM THE ACTIVATED SLUDGE AND THE HIGH RATE BIOLOGICAL FILTER SYSTEMS.
RESULTS SHOWED THAT TILAPIAS IN BOTH PONDS GREW AND SURVIVED WELL WITHOUT FEEDING. THOSE IN THE SECOND POND WERE MORE PRODUCTIVE AS A RESULT OF THE HIGHER NUTRIENT CONTENTS.
+ THE BACTERIA AND HEAVY METAL CONTENTS DETECTED IN THE FISH WERE FOUND TO BE SIMILAR TO THOSE IN COMMERCIAL SPECIES AND WERE WITHIN SAFETY LIMITS FOR HUMAN CONSUMPTION, MR SIN SAID.
EXPERIMENTS WERE ALSO CONDUCTED TO ASSESS THE FEASIBILITY OF CULTURING TRADITIONAL CHINESE CARPS SUCH AS SILVER CARP, BIGHEAD, GRASS CARP AND COMMON CARP,
+THE SILVER CARP AND BIGHEAD GREW BETTER IN THE OXIDATION PONDS THAN IN COMMERCIAL PONDS UNDER NORMAL SITUATION WHILE THE GROWTH OF THE COMMON CARP WAS SATISFACTORY.
+ HOWEVER, THE SURVIVAL AND GROWTH RATES OF THE GRASS CARP IN BOTH PONDS WERE CONSIDERED POOR PROBABLY BECAUSE THE WATER QUALITY WAS NOT SUITABLE FOR ITS GROWTH,+ MR SIN SAID.
FURTHER STUDIES WOULD BE REQUIRED BEFORE LARGESCALE PRODUCTION COULD BE INTRODUCED, HE ADDED.
WAN CHAI CONTEST TO FOCUS ON CONCERN FOR ELDERLY
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A COMPETITION ON CREATIVE SCRIPT-WRITING FOR SLIDE-SHOWS WITH THEMES RELATING TO THE ELDERLY WILL BE ORGANISED BY THE WAN CHAI DISTRICT BOARD TO PROMOTE RESPECT AND CARE FOR SENIOR CITIZENS AMONG YOUTHS IN THE DISTRICT.
THE BEST SCRIPT WILL BE USED TO PRODUCE A SET OF SLIDES WITH THE ASSISTANCE OF VOLUNTEERS FROM THE METHODIST CENTRE, AND WILL BE ON LOAN TO VARIOUS ORGANISATIONS TO FURTHER PROMOTE CONCERN FOR THE ELDERLY.
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/DETAILS F