7 WASTE MANAGEMENT IMPLICATIONS

Transcription

1 80 7 WASTE MANAGEMENT IMPLICATIONS This section presents the management and disposal strategy of the wastes generated from the construction and operational phases of the proposed Wholesale Fish Market at Tuen Mun Area 44. It is based upon the waste management principle of reducing the amount of waste requiring final disposal through the development. 7.1 Generation of Waste (i) Construction Phase The construc tion works of the subject development mainly include foundation work and superstructure construction. The estimated periods for the foundation work and superstructure construction are 9 months and 17 months respectively Since the existing land uses at the subject site are mainly open area and temporary car parks, the demolition waste is limited. The majority of solid waste originates from the soil excavation and removal from piling activities of the foundation works. The estimated quantity of soil to be removed is approximately 3,000 to 5,000 cubic meters A few cubic meters of chemical waste such as lubricants and thinners will be generated throughout the whole construction period. Wooden boards for moulding and spent concrete during concreting of piles or pilecap and superstructures is a possible source of solid waste generation, reusable steel hoarding and covered walkways will be employed, minimal amount of solid waste generation from hoarding works is anticipated The types, quantities and time period of wastes generated during the construction phase are estimated in Table 7.1. Table 7.1 Details of Waste Generation during Construction Phase Construction Period Type of Waste Quantity Foundation work Excavated soil 3,000 5,000 m 3 Foundation work & superstructure construction Wooden board Spent concrete Steel Chemical waste (lubricants and thinners) 900m 3 1,200m 3 900m 3 ~ 5m The disposal options and quantities of construction waste to be disposed of off-site or reused/recycled are estimated in Table 7.2. It is assumed that 25% of the excavated soil, spent concrete, steel and timber can be reused or recycled.

2 81 Table 7.2 Quantity of Construction Waste for Off-Site Disposal or Reuse/Recycle Disposal Options Type of Waste Quantities Off-site disposal at landfills Timber, steel 1,350 m 3 Off-site disposal at public Excavated soil, spent 3,900 m 3 fill concrete Chemical Waste Treatment Centre Lubricants, thinners ~5m 3 Reuse/recycle Excavated soil, spent 1,750 m 3 concrete, steel and timber (i) Operational Phase The details of waste generation during the operation of the proposed development, are shown in Table 7.3. Trade waste and municipal waste are generally generated. No hazardous waste is anticipated during the operational phase. Table 7.3 Details of Waste Generation during Operational Phase Proposed Facilities Type of Waste Quantity Wholesale Fish Market - Paper/newspaper and dead m 3 /day* fish contained in foam boxes - Sewage discharge m 3 /day a Community Hall General domestic waste 1.6kg/capita/day 1 Other Possible Paper and clear plastic bottles 10 kg/day* Community Uses RCP Municipal solid waste 13,200 litres/day* Marine RCP Polyfoam, timber and plastic bags 3 tonnes/day* a Assume 70% of total water consumption (7.7m 3 /day) will be discharged. *Information provided by relevant Government Departments. The details of the waste handling of the RCP and MRCP are shown in Table 4. Table 7.4 Details of Waste Handling of the RCP and MRCP Facilities Type of Waste Operation Period Quantity RCP Newspaper, plastic 07:00 08:00 80kg/day bag and foam box MRCP Polyfoam, timber 08:00 18:00 3 tonnes/day and plastic bag Information provided by relevant Government Departments. 7.2 Waste Management The general approach of the waste management includes elimination, reduction, reuse, treatment and disposal of waste. In this section, waste management practices are introduced in order to minimise the amount of waste to be generated and maximise the reuse of materials. 1 Howard S. Peavy, Donald R. Rowe & George Tchobanoglous, Environmental Engineering, Table 11-2, McGraw Hill Book Company, 1985

3 82 (i) Construction Phase During construction phase, various types of construction waste in the form of wastewater, solid waste such as vegetation, soil and plywood, and chemical waste such as lubricant and thinner will be produced. The following the general good site practice and waste management: (a) Reusable materials such as metallic board for formworks can be considered to avoid the use of plywood, which is less reusable and durable. (b) Garbage from office and site workers will be segregated from construction waste and will be contained and disposed of to proper refuse collection point. Recyclable materials such as waste paper from clerical works, plastic bottles and aluminium cans can be segregated and sent to proper waste collectors for recycling. (c) The recommended construction waste management strategy is to segregate the inert and non-inert portions of waste. The inert portion, including excavated soil, will be disposed of at a public fill. The construction of the proposed WFM would require the preparation of a Waste Management Plan (WMP) prior to the commencement of the construction works. The site of the public fill should be identified when preparing the WMP. The non-inert portion of waste should be reused/recycled whenever possible. Disposal of the non-inert portion of waste to landfill site should be considered as the last resort. (d) During the construction works, one should register as chemical waste producer with EPD if chemical waste is produced and chemical waste should be collected by licensed a collector. Disposal of chemical waste such as lubricants and thinners will be handled in accordance with the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes published under the WDO Section In order to minimise the generation of construction waste, specific mitigation measures should be adopted during the design and construction stages to minimise the waste generation. Planning & Design Stages Minimise required excavation of soil and material used during the design of foundation structure & superstructure. Evaluate the potential of re-using of excavated soils for back-filling and landscaping purposes. Design and provide an area within the construction site to allow on-site sorting and segregation of waste materials. Construction Stage Segregate all reusable and recyclable waste materials and store in different containers, skips or stockpiled. Separate inert construction materials for either re-use on-site or dispose of at public fill. Provide temporary storage areas for storing and stockpiling reusable and recyclable materials.

4 83 Provide training to site staff about waste minimisation practices including waste reduction, reuse and recycling. The following mitigation measures should also be adopted for managing the disposal of construction material: Separate the inert and non-inert portions of construction material for disposal of public fill and landfill respectively. Employ approved licensed waste collectors to collect the inert construction materials to be disposed of at public fill. Maintain accurate site record throughout the construction works detailing the quantities of materials generated on site, reused on site, disposed off-site together with disposal routes/locations. Monitor the disposal of construction waste at public fills and landfills, and control free-tipping by a trip-ticket system. Reference should be made to WBTC No.5/99 Trip-ticket System for Disposal of Construction and Demolition Material. Waste Management Plan A Waste Management Plan (WMP) will be included in the building contract in accordance with the Works Bureau Technical Circular No. 29/2000 to set out the disposal strategy and waste management practice for the following: minimise potential adverse impacts associated with waste arising from the construction activities implement the aforementioned proposed mitigation measures properly and effectively. The WMP is to be submitted to the Architect for approval and proper implementation by the contractor during the construction phase. The Contractor shall review the WMP at monthly intervals and shall submit a revised and updated WMP if necessary. (ii) Operational Phase Waste generation sources originate from the operation of the wholesale fish market, community hall, public toilets, management offices and other possible community uses. Waste in the form of wastewater will be discharged to public sewer and solid waste will be gathered at the RCP. (a) Solid waste generated from the fish market includes dead fish, plastic bags and polyfoam boxes. Unlike dead fish, plastic bags are difficult to decompose in the landfill. In order to minimise the amount of waste disposal, reusable containers can be used instead of plastic bags. As advised by AFCD, fishermen and fish traders reuse the polyfoam boxes as many times as possible until they are broken. In addition, FMO has liaised with a company to collect broken polyfoam boxes for recycle, therefore, mitigation measures for polyfoam waste generation are unlikely to be required. The design should allow for separation and suitable storage of broken polyfoam casings prior to collection.

5 84 (b) Municipal solid waste generated from community hall, offices and other possible community uses will be segregated. Reuse of materials will be practised, as for example single-sided paper for rough works, as much as possible within the subject development. Any recyclable and reusable materials will be collected and sent to waste collectors for regeneration. (c) It is anticipated that the dead fish will not cause significant adverse impact since only a small amount of dead fish (0.14m 3 /day) will be generated and the dead fish will be disposed of at nearby RCP and dispatched for final disposal everyday from the RCP. The dead fish will not be kept for a long time at the WFM complex. Nevertheless, in order to minimise the potential odour and health problem, it is recommended that the dead fish should be kept in a sealed durable and reusable container before being wrapped in plastic for daily disposal at the adjacent RCP.