SATURDAY, MARCH 24, 1979
HOWEVER MR. WONG POINTED OUT THAT PROGRESSIVELY AFTER THE WAR INTERCEPTING SEWERS WERE CONSTRUCTED TO CONVEY ALL SEWAGE TO A CENTRAL SCREENING PLANT TO REMOVE LARGE SOLIDS AND FLOATING OBJECTS.
THE SCREENED SEWAGE WAS THEN DISCHARGED IN DEEP WATERS THROUGH LONG SUBMARINE OUTFALLS TO ACHIEVE ADEQUATE INITIAL DILUTION AND SUBSEQUENT DISPERSION.
*FOR DISCHARGES INTO STREAMS OR WHERE SEA CURRENTS ARE WEAK, FURTHER TREATMENT OTHER THAN SCREENING IS USUALLY NECESSARY, HE SAID.
IN 1974, THE FIRST SECONDARY SEWAGE TREATMENT WORKS WHICH WAS AN EXPERIMENTAL PLANT, WAS BUILT IN SHEK WU HUI.
IN THE FOLLOWING YEAR A TEMPORARY SEWAGE TREATMENT WORKS FOR SHA TIN WAS COMMISSIONED.
SINCE THEN, MORE SECONDARY TREATMENT WORKS HAVE BEEN PUT UNDER CONSTRUCTION IN THE NEW TERRITORIES. AND TWO OF THEM, THE SHA TIN INTER IM SEWAGE TREATMENT PLANT AND THE TAI PO SEWAGE TREATMENT WORKS (STAGE 1), ARE EXPECTED TO BE COMMISSIONED LATER THIS YEAR.
THESE SECONDARY TREATMENT PLANTS EMPLOY BIOCHEMICAL PROCESSES, IN ADDITION TO PHYSICAL TREATMENT, TO REMOVE THE POLLUTANTS. IN GENERAL, AT LEAST 92 PER CENT REMOVAL IS ACHIEVED,
TURNING TO THE EXPERIMENTAL PLANT IN SHEK WU HUI, MR. WONG SAID: IT HAS BEEN USED TO OBTAIN DESIGN DATA FOR VARIOUS BIOLOGICAL TREATMENT PROCESSES TO FIND THE MOST SUITABLE PROCESS FOR HONG KONG AND TO TRAIN LOCAL OPERATION PERSONNEL.
+EXPERIENCE AND FEED-BACK OF PERFORMANCE DATA FROM OPERATION OF OTHER PLANTS ARE ALSO A USEFUL SOURCE OF REFERENCE FOR THESE PURPOSES.+
TO MONITOR THE CHARACTER ISTICS OF SEWAGE AND THE QUALITY OF THE TREATED EFFLUENT AND TO ENSURE THAT THE PLANTS ARE PRODUCING EFFLUENTS OF SATISFACTORY QUALITY, MR. WONG SAID: +ABOUT 420 TESTS ARE CARRIED OUT AT THE SHEK WU HUI PILOT PLANT EACH MONTH AND 210 TESTS AT THE SHA TIN TEMPORARY PLANT.
+ALSO, TERRITORIAL WATERS ARE MONITORED TO ASSESS THE EFFECTIVENESS OF SEWAGE TREATMENT AND DISPOSAL FACILITIES TO ESTABLISH POLLUTION TREND DATA FOR DESIGN PURPOSES AND TO PROVIDE AN EARLY WARNING FOR THE TIMELY IMPLEMENTATION OF NECESSARY SEWAGE TREATMENT TO PREVENT DETERIORATION IN THE CONDITIONS OF THE RECEIVING WATER BODIES.+