| (Water Pollution Control Ordinance, Cap 358 section 21) [30 November 1990] (Special Gazette Supplement No. 5 dated 30.11.1990) Cap 358AK Part 1 PRELIMINARY PART I PRELIMINARY 1. Citation and commencement 1.1 This technical memorandum is issued under section 21 of the Water Pollution Control Ordinance. It may be cited as the Technical Memorandum on Effluent Standards. 2. Application and scope 2.1 The Technical Memorandum on Effluent Standards is a guide to the Authority under the Ordinance. It sets the limits that make effluents acceptable into foul sewers, storm water drains, inland and coastal waters. The limits control the physical, chemical and microbial quality of effluents. 2.2 The standards apply to effluents through licences, which the Authority issues under sections 15, 16 and 20 of the Ordinance. The Authority is the Director of Environmental Protection. He will consult this memorandum when fixing the conditions that he will include in a licence. He will not normally impose conditions that are more stringent than those in the memorandum. To do so, he must have good reason. 2.3 Where a user takes water from a nature water course or water body, and then returns it after use, different standards may apply. The Authority will not impose standards requiring the effluent to be cleaner than the water that the user takes. 2.4 This memorandum does not apply to discharges or deposits of wastes that are controlled by the Waste Disposal (Livestock Waste) Regulations (Cap 354 sub. leg.). Nor does it apply to dredging, dumping for land formation or solid waste disposal. Other laws and standards control them. The memorandum does apply to all other discharges and deposits. 2.5 This memorandum sets standards for effluents that differ in different areas and between surface waters and sewers. The standards also vary with the rate of effluent flow, which the Authority may also limit. 2.6 The flow rates the memorandum covers appear in Tables 1 to 10b. The Authority will set standards for effluents outside the listed flow ranges case by case. Standards for effluents above the highest flow band will be more stringent than those in the tables. 2.7 Some effluents may have characteristics or components that are not listed and could be harmful. In these cases, the Authority may set limits case by case. There are certain general prohibitions that apply besides the tables, which are listed in paragraphs 6.2, 8.4 and 9.2. 2.8 At present, the Government Chemist is the only analyst designated by the Ordinance. He alone certifies the quality of an effluent sample in a prosecution. The effluent standards refer to his analytical methods, which appear for reference only in Annex I. 3. Interpretation 3.1 This memorandum uses standard scientific terms. Where the Ordinance defines a term, that definition applies. 3.2 In this memorandum the following definitions also apply. "Effluent" (流出物) means any discharge or deposit subject to control under the Ordinance. "Coastal waters" (海岸水域) means the waters of Hong Kong except inland waters and storm water drains. "Inshore waters" (沿岸水域) means all coastal waters where the water depth is less than 6m at mean low tide, or that are within 200m of the mean low water mark, whichever position is further from the shore. "Marine waters" (海洋水域) means all coastal waters except inshore waters. "Flow rate" (流量率) means the measured volume per unit time of effluent from a premises, averaged over the period of operation in any day accepted by the Authority. Where the flow cannot by measured, it is determined by a method the Authority approves. "Foul sewer" (脏水渠) means a sewer built for the carriage of foul or waste water or so designated by the Authority. "Storm water drain" (雨水渠) means a man made conduit built for natural surface drainage or so designated by the Authority. "Toxic metals" (有毒金属) includes antimony, arsenic, beryllium, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, thallium, vanadium and any other metals that the Authority specifies. 4. Determining the acceptable characteristics of effluents 4.1 The Ordinance allows the Government to declare water control zones and to set water quality objectives. The objectives describe the water quality that will promote the conservation and best use of the waters in the public interest. 4.2 In deciding whether to grant a licence for an effluent, the Authority's purpose is to meet the relevant objectives. The same purpose governs the conditions that the Authority attaches to the licence. He also must consider the need to protect the drainage or sewerage system, including disposal works, treatment processes, and the health and safety of workers in them. 4.3 Each control zone contains four systems into which wastes may be discharged. They are foul sewers, storm water drains, inland waters (which include water in the ground) and coastal waters. |
