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THURSDAY, JANUARY 13, 1983
POWER STATION'S POLLUTION CONTROLS EXAMINED
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THE ENVIRONMENTAL PROTECTION ADVISORY COMMITTEE (EPCOM) THIS WEEK VISITED THE HONG KONG ELECTRIC COMPANY'S COAL-FIRED POWER STATION ON LAMMA ISLAND, TO VIEW AT FIRST HAND THE POLLUTION-CONTROL ARRANGEMENTS INCORPORATED INTO THE PLANT'S DESIGN UNDER PLANS DRAWN UP BY THE COMPANY AND AGREED WITH THE GOVERNMENT.
AFTER A VERY THOROUGH TOUR OF INSPECTION THE COMMITTEE EXPRESSED THEMSELVES PLEASED WITH WHAT THEY SAW. THE PLANS LAID HAD BEEN TURNED INTO REAL CONTROLS.
POTENTIAL SOURCES OF POLLUTION FROM SUCH A POWER STATION FALL INTO FOUR MAIN CATEGORIES-EMISSIONS FROM THE CHIMNEY, AIR AND WATER POLLUTION FROM THE HANDLING OF THE COAL STOCKS, SIMILARLY, FROM THE HANDLING AND DISPOSAL OF PULVERISED FLY ASH (PFA) AND FURNACE BOTTOM ASH (FBA) EXTRACTED FROM THE CHIMNEY AND BOILERS, AND EFFLUENTS FROM THE COOLING WATER AND SEWAGE DISCHARGES FROM THE STATION. ALL THESE SOURCES HAD BEEN MADE THE SUBJECT OF ADVANCED TECHNICAL CONTROLS, OPERATED WITH PROFESSIONAL EFFICIENCY.
ELECTROSTATIC PRECIPITATORS SEPARATE THE PFA EMISSIONS SO THAT THESE ARE NOT RELEASED THROUGH THE CHIMNEY AS SMOKE AND DUST. THE PFA IS THEN SUCKED BY AIR THROUGH PIPES TO STORAGE BINS IN A TOTALLY ENCLOSED SYSTEM.
FINAL DISPOSAL IS TO THE PRODUCTION OF CEMENT ADDITIVES.
CONTINGENCY ARRANGEMENTS ARE UNDER DISCUSSION BETWEEN THE COMPANY AND THE GOVERNMENT FOR SAFE DISPOSAL AT CONTROLLED TIPS, SHOULD THESE COMMERCIAL OUTLETS AT ANY TIME BE UNABLE TO TAKE UP THE FULL OUTPUT OF PFA FROM THE STATION.
FBA IS EXTRACTED FROM THE BASE OF THE BOILERS AND SLUICED WITH WATER THROUGH PIPES TO A SETTLEMENT BASIN, IN WHICH THE MOISTURISED ASH IS SEPARATED OUT AND LOADED INTO BARGES FOR DISPOSAL TO COMMERCIAL USE IN THIS CASE AS MATERIAL FOR CEMENT BLOCKS. SIMILAR CONTINGENCY ARRANGEMENTS ARE UNDER DISCUSSION WITH THE GOVERNMENT FOR DISPOSAL OF THIS FORM OF ASH TO TIPS, SHOULD THE COMMERCIAL OUTLETS PROVE INSUFFICIENT.
EPCOM MEMBERS WERE ABLE TO WATCH THE COAL-HANDLING AND UNLOADING OPERATIONS DIRECTLY, AS THEIR VISIT COINCIDED WITH THE UNLOADING OF AN 82 000 TON SHIPMENT OF AMERICAN COAL FROM A VESSEL RECENTLY ARRIVED AT THE LAMMA STATION.
DESPITE THE WORK IN PROGRESS VERY LITTLE SPILLAGE WAS OBSERVABLE ON THE JETTY AND ARRANGEMENTS WERE IN FORCE TO SWEEP UP AND RETAIN FOR USE SUCH AMOUNTS AS DID ESCAPE IN TRANSFER FROM THE SHIP TO COVERED CONVEYOR BELTS, WHICH MOVE THE COAL EITHER DIRECTLY INTO THE POWER STATION OR TO THE STOCKPILES ADJACENT TO THE BUILDING.
/ON ARRIVAL