6 Waste management implications

6.2 Environmental Legislation and Standards

6.2.1 The following legislation relates to the handling, treatment and disposal of wastes in the Hong Kong SAR and was used in assessing potential impacts:

· Waste Disposal Ordinance (Cap. 354);

· Waste Disposal (Chemical Waste) (General) Regulation (Cap. 354);

· Land (Miscellaneous Provisions) Ordinance (Cap. 28);

· Public Health and Municipal Services Ordinance (Cap. 132) - Public Cleansing and Prevention of Nuisances Regulation; and

· Dumping At Sea Ordinance (Cap. 466).

Waste Management

6.2.2 The Waste Disposal Ordinance (WDO) prohibits the unauthorised disposal of wastes. Construction waste is not directly defined in the WDO but is considered to fall within the category of “trade waste”. Trade waste is defined as waste from any trade, manufacturer or business, or any waste building, or civil engineering materials, but does not include animal waste. Under the WDO, wastes can be disposed of at sites licensed by the Environmental Protection Department (EPD).

6.2.3 Under the regulation of WDO, the Chemical Waste (General) Regulation 1992 provides regulations for chemical waste control, and administers the possession, storage, collection, transport and disposal of chemical wastes. The EPD has also issued a ‘guideline’ document, the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes (1992), which details how the Contractor should comply with the regulations on chemical wastes.

6.2.4 The Public Cleansing and Prevention of Nuisances Regulation provides control on illegal tipping of wastes on unauthorised (unlicensed) sites.

Construction and Demolition (C&D) Materials

6.2.5 The current policy related to the dumping of C&D material^([1]) is documented in the Works Branch Technical Circular No. 2/93, ‘Public Dump’. Construction and demolition materials that are wholly inert, namely public fill, should not be disposed of to landfill, but taken to public filling areas which usually form part of reclamation schemes. The Land (Miscellaneous Provisions) Ordinance requires that dumping licences are obtained by individual or companies who deliver public fill to public filling areas. The licences are issued by the Civil Engineering and Development Department (CEDD) under delegated powers from the Director of Lands.

6.2.6 In addition to the Works Branch Technical Circular (WBTC), EPD and CEDD have produced a leaflet titled ‘New Disposal Arrangements for Construction Waste’ (1992) which states that C&D material with less than 30% by weight of inert material (that is, public fill) will be accepted at landfill. If the material contains more than 30% inert material, the waste must be sorted with suitable material and sent to public filling area and the non-inert material (that is, C&D waste) sent to landfill for final disposal.

6.2.7 Measures have been introduced under Environment, Transport and Works Bureau (ETWB) TCW No. 33/2002 to enhance the management of C&D material including rock, and to minimize its generation at source. The enhancement measures include: (i) drawing up a Construction and Demolition Material Management Plan (C&DMMP) at an early design stage to minimize C&D material generation; (ii) vetting of the C&DMMP prior to upgrading of the project to Category A in the Public Works Programme; and (iii) providing the contractor with information from the C&DMMP in order to facilitate him in the preparation of the Waste Management Plan (WMP) and to minimize C&D material generation during construction. Projects generating less than 50,000m³ C&D material or importing less than 50,000m³fill materialare exempt from the C&DMMP. A new technical circular ETWB TCW 15/2003 was recently issued to introduce additional measures to enhance waste management on construction sites. The circular sets out the policy and procedures requiring contractors to prepare and implement an enhanced WMP to encourage on-site sorting of C&D material and to minimize their generation during the course of construction.

6.2.8 The ETWB TCW No. 34/2002 sets out the management framework for dredged/excavated sediment. This Technical Circular outlines the procedures to be followed in assessing and classifying sediment and explains the marine disposal arrangement for the classified material. The sediment quality criteria for the classification of sediment are presented in Table 6.1. Dumping permits from EPD are required for marine disposal of dredged/excavated materials.

6.3 Assessment Methodology

General

6.3.1 The methodology for assessing potential waste management impacts during the construction phase of the Project included the following tasks:

· estimation of the types and quantities of wastes to be generated as a result of construction activities;

· assessment of potential impacts from the management of solid wastes with respect to potential hazards, air and odour emissions, noise and wastewater discharges;

· evaluation of the opportunities for reducing waste generation;

· identification of disposal options for each type of waste; and

· assessment of impacts on the capacity of waste collection, transfer and disposal facilities.

Excavated Riverbed Material

6.3.2 A sediment quality characterization survey was carried out in December 2003 to characterize the level of contamination in the riverbed material of Pak Ngan Heung River, Tai Tei Tong River, Luk Tei Tong River and Luk Tei Tong (2) River for the purpose of this EIA. The works comprised collecting samples at a total of seven locations within the three river channels for chemical testing (Figure 6.1). The methodology for the sampling and laboratory testing of the riverbed samples was agreed with EPD prior to the commencement of the survey.

6.3.3 The riverbed samples were tested in the laboratory for the following parameters:

(i) Metals concentrations including chromium (Cr), copper (Cu), mercury (Hg), lead (Pb), cadmium (Cd), nickel (Ni), zinc (Zn), silver (Ag) and arsenic (As).

(ii) Concentrations of organic compounds: total polychlorinated biphenyls (PCBs) and polyaromatic hydrocarbons (PAHs).

6.3.4 The chemical contaminant criteria under the management and classification system for excavated material destined for marine disposal are listed in Table 6.1 below.

Table 6.1 Sediment Quality Classification Criteria

Contaminants	LCEL	UCEL
*Heavy Metal (mg/kg dry weight)*
Cadmium (Cd)	1.5	4
Chromium (Cr)	80	160
Copper (Cu)	65	110
Mercury (Hg)	0.5	1
Nickel (Ni)	40	40
Lead (Pb)	75	110
Silver (Ag)	1	2
Zinc (Zn)	200	270
*Metalloid (mg/kg dry weight)*
Arsenic	12	42
*Organic-PAHs (µg/kg dry weight)*
PAHs (Low Molecular Weight)	550	3160
PAHs (High Molecular Weight)	1700	9600
*Organic-non-PAHs (µg/kg dry weight)*
Total PCBs	23	180

Source: Appendix A of ETWB TCW No. 34/2002 Management of Dredged / Excavated Sediment

Note: LCEL – Lower Chemical Exceedance Level

UCEL – Upper Chemical Exceedance Level

6.3.5 Sediments are categorised with reference to the LCEL and UCEL, as follows:

Category L Sediment with all contaminant levels not exceeding the LCEL. The material must be dredged, transported and disposed of in a manner that minimises the loss of contaminants either into solution or by suspension.

Category M Sediment with any one or more contaminant levels exceeding the LCEL and none exceeding the UCEL. The material must be dredged and transported with care, and must be effectively isolated from the environment upon final disposal unless appropriate biological tests demonstrate that the material will not adversely affect the marine environment.

Category H Sediment with any one or more contaminant levels exceeding the UCEL. The material must be dredged and transported with great care, and must be effectively isolated from the environment upon final disposal.

6.3.6 For projects with disposal requirements of less than 50,000 m³Category L sediment, the allocation of sediment disposal space had been delegated to Director of Environmental Protection (DEP) in accordance with ETWB TCW No. 34/2002.

6.3.7 The chemical testing results of the riverbed samples as compared with the classification criteria are presented in Table 6.2. The chemical testing results indicate that Category L material was found at all sampling locations.

Table 6.2 Contaminant Levels of Riverbed Soil Samples and Their Categories

Sampling Station No.	LMW	HMW	Total PCBs	Metals									Overall Category
	PAHs	PAHs	Total PCBs	mg/kg
	ug/kg	ug/kg	Ug/kg	Ag	As	Cd	Cr	Cu	Ni	Pb	Zn	Hg
S1	<550	<1700	<23	<0.1	1.1	0.1	<1	1.8	<1	22	37	0.09	L
S2	<550	<1700	<23	0.4	1.8	<0.1	2.1	4.0	1.2	23	47	0.2	L
S3	<550	<1700	<23	0.2	11	0.1	2.7	2.3	<1	10	55	0.1	L
S4	<550	<1700	<23	<0.1	6.5	<0.1	2.2	4.5	1.2	18	42	0.09	L
S5	<550	<1700	<23	0.4	<1	<0.1	2.2	2.0	1.1	22	44	0.2	L
S6	<550	<1700	<23	0.3	1.7	0.1	3.9	2.7	1.2	34	31	0.1	L
S7	<550	<1700	<23	0.5	2.4	<0.1	1.5	1.7	<1	7.6	22	0.3	L

Notes:

1. LMW = Low molecular weight PAHs, that is, acenaphthene, acenaphthylene, anthracene, fluorene, naphthalene and phenanthrene.

2. HMW = High molecular weight PAHs, that is, benzo[a]anthracene, benzo[a]pyrene, chrysene, dibenzo[a,h]anthracene, fluoranthene, pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, indeno[1,2,3-c,d]pyrene and benzo[g,h,i]perylene.

6.4 Identification of Evaluation of Environmental Impacts

6.4.1 The construction activities to be carried out for the proposed Project would generate a variety of wastes that can be divided into distinct categories based on their composition and ultimate method of disposal. The identified waste types include:

· construction and demolition (C&D) materials;

· chemical waste; and

· general refuse.

6.4.2 The nature of each type of waste arising is described in the following section, together with an evaluation of the potential environmental impacts associated with these waste arisings.

6.4.3 During the operation phase, maintenance desilting would be required for the river channels. Desilting will be carried out by excavators or labourers as described in Section 2.7. The removed silt and debris will then be loaded into covered lorries and transported to the designated landfill site for disposal.

Construction and Demolition (C&D) Materials

6.4.4 Construction of the drainage improvement works for Pak Ngan Heung River, Tai Tei Tong River, Luk Tei Tong River and Luk Tei Tong By-pass Channel (2) River would involve earthworks for the new river channels to the required profile and formation levels, and for the outlets to the Silver River. The excavated materials would comprise mostly soil, gravel and boulders from the fields and river/stream channels. Based on the preliminary design, the total volume of excavated material from the construction of the river channels was estimated by the Project Engineer to be approximately 82,24845,20045 m³.

6.4.5 The results of the sampling and laboratory testing provide information on the characteristics of the excavated material from the riverbed. The samples collected at all 7 sampling locations were described as coarse gravel. Excavated material from the river improvement works would be suitable for disposal to a public filling area.

6.4.6 It was estimated by the Project Engineer that approximately 96,400,000 m³ of the excavated material from the construction of the river channels could be reused on-site as fill material for backfilling of the box culverts and drainage pipes. Temporary stockpiles of excavated materials would be required on-site before disposal. Considering the unpolluted nature of the excavated material, reuse on-site would not result in any unacceptable environmental impact. It is proposed that small cobbles and rocks from the existing rivers be re-used in the recreated channel beds as far as possible, subject to suitable size requirements. Surplus excavated material (approx. 38,8004573,248 m³) would be transported by trucks to the designated barging point for disposal at the designated public filling area, or transported directly to the public filling area.

6.4.7 C&D material would also be generated from the demolition of existing crossings over the river channels and structures. The total volume of C&D material was estimated by the Project Engineer to be approximately 2,4363,462 m³ and would comprise mostly concrete, brick, metal and cement plaster/mortar. C&D waste would be generated during site clearance and the estimated volume of C&D waste for a contract of this size was approximately 12,47218,180 m³. These C&D wastes would comprise vegetation and top soil and would be delivered to a designated landfill site for disposal. A summary of the estimated volumes of surplus excavated material generated from earthworks for the new river channels, as well as C&D material generated from the demolition of existing crossings and structures and from site clearance is presented in Table 6.3 below.

Table 6.3 Summary of C&D Material Volumes

Location	Surplus Excavated Material (m³)		C&D Waste (m³)		C&D Material (m³)
Location	River Channel	Structures	Site Clearance	Structures
Pak Ngan Heung River Apr ‘08 – Jun ‘09	12,480	381	4,500	95	17,457
Luk Tei Tong ~~(2) River~~By-pass Channel Nov ’08 – Mar ‘09	10,172~~16,668~~	213~~126~~	4,300~~5,560~~	5331	14,739~~22,385~~
Luk Tei Tong River Apr ’07 – Jul ‘08	12,300	853	3,520	213	16,887
Tai Tei Tong River Apr ’07 – Oct ‘07 Nov ’08 – Jan ‘09	31,80093	~~588~~1,323	~~4,600~~152	~~147~~331	~~37,13~~5,699
Total	~~73,248~~38,845	2,770~~1,949~~	~~18,180~~12,472	~~487~~692	~~93,864~~54,782
*Say*	*~~75,200~~41,700*		*13,200~~18,700~~*		*~~93,900~~54,800*

Note:

1. All volumes are bulk volumes, assuming bulk volume : in-situ volume = 1 : 0.75

2. Surplus excavated material to be disposed to public filling area

3. C&D waste to be disposed to landfill

Chemical Waste

6.4.8 The maintenance and servicing of construction plant and equipment may possibly generate some chemical wastes, for instance, cleaning fluids, solvents, lubrication oil and fuel. Maintenance of vehicles may also involve the use of a variety of chemicals, oil and lubricants.

6.4.9 Since a large number of the construction activities will be carried out in close proximity to river and stream channels and residential dwellings, chemical wastes arising during the construction phase may pose environmental, health and safety hazards if not stored and disposed of in an appropriate manner as stipulated in the Waste Disposal (Chemical Waste) (General) Regulations. The potential hazards include:

· toxic effects to workers;

· adverse impacts on water quality from spills and associated adverse impacts on fresh water biota; and

· fire hazards.

6.4.10 Materials classified as chemical wastes will require special handling and storage arrangements before removal for appropriate treatment at the Chemical Waste Treatment Facility at Tsing Yi. Wherever possible opportunities should be taken to reuse and recycle materials. Mitigation and control requirements for chemical wastes are detailed in Section 6.5.10. Provided that the handling, storage and disposal of chemical wastes are in accordance with these requirements, adverse environmental impacts are not expected to result.

General Refuse

6.4.11 Throughout the construction stage, the workforce would generate general refuse comprising food scraps, waste paper, empty containers, etc. Release of general refuse into the river and stream channels should not be permitted as introduction of these wastes is likely to have detrimental effects on water quality in the area. Effective collection of site wastes would be required to prevent waste materials being blown around by wind, flushed or leached into the aquatic environment, and odour nuisance. The work sites may also attract pests and vermin if the waste storage area is not well maintained and cleaned regularly. Disposal of refuse at sites other than approved waste transfer or disposal facilities can also result in similar impacts.

6.4.12 With the implementation of the recommended waste management practices at the site, adverse environmental impacts would not arise from the storage, handling and transportation of refuse.

6.5 Mitigation Measures

Good Site Practices

6.5.1 Appropriate waste handling, transportation and disposal methods for all waste arisings generated during the construction works should be implemented to ensure that construction wastes do not enter the river and stream channels.

6.5.2 It is expected that adverse impacts from waste management would not arise, provided that good site practices are strictly followed. Recommendations for good site practices during construction include:

· nomination of approved personnel, such as a site manager, to be responsible for good site practices, and making arrangements for collection of all wastes generated at the site and effective disposal to an appropriate facility;

· training of site personnel in proper waste management and chemical waste handling procedures;

· provision of sufficient waste disposal points and regular collection for disposal;

· appropriate measures to minimise windblown litter and dust during transportation of waste by either covering trucks or by transporting wastes in enclosed containers;

· regular cleaning and maintenance programme for drainage systems, sumps and oil interceptors;

· a recording system for the amount of wastes generated, recycled and disposed (including the disposal sites) should be proposed; and

· a Waste Management Plan should be prepared and submitted to the Engineer for approval. One may make reference to ETWB TCW No. 15/2003 for details.

6.5.3 In order to monitor the disposal of C&D material at landfills and public filling areas, as appropriate, and to control fly tipping, a trip-ticket system should be included as one of the contractual requirements to be implemented by an Environmental Team undertaking the Environmental Monitoring and Audit work. One may make reference to WBTC No. 21/2002 for details.

Waste Reduction Measures

6.5.4 Good management and control can prevent the generation of significant amounts of waste. Waste reduction is best achieved at the planning and design stage, as well as by ensuring the implementation of good site practices. Recommendations to achieve waste reduction include:

· segregation and storage of different types of waste in different containers, skips or stockpiles to enhance reuse or recycling of materials and their proper disposal;

· separate labelled bins should be provided to segregate aluminium cans from other general refuse generated by the workforce, and to encourage collection of by individual collectors;

· any unused chemicals or those with remaining functional capacity should be recycled;

· maximising the use of reusable steel formwork to reduce the amount of C&D material;

· prior to disposal of C&D waste, it is recommended that wood, steel and other metals should be separated for re-use and / or recycling to minimise the quantity of waste to be disposed of to landfill;

· proper storage and site practices to minimise the potential for damage or contamination of construction materials;

· plan and stock construction materials carefully to minimise amount of waste generated and avoid unnecessary generation of waste; and

· minimize over ordering of concrete, mortars and cement grout by doing careful check before ordering.

6.5.5 In addition to the above good site practices and waste reduction measures, specific mitigation measures are recommended below for the identified waste arisings to minimise environmental impacts during handling, transportation and disposal of these wastes.

Construction and Demolition Material

6.5.6 The C&D material generated from the river improvement works would comprise public fill, being excavated soil, gravel and boulders. To minimise off-site disposal of public fill, the excavated material with suitable characteristics/size should be reused on-site as fill material as far as practicable, such as for backfilling of box culverts and drainage pipes, and small cobbles and rocks should be used in the construction of the recreated channel bed.

6.5.7 When disposing C&D material at a public filling area, it should be noted that the material shall only consist of soil, rock, concrete, brick, cement plaster/mortar, inert building debris, aggregates and asphalt. The material shall be free from marine mud, household refuse, plastic, metals, industrial and chemical waste, animal and vegetable matter, and other material considered to be unsuitable by the Filling Supervisor.

6.5.8 The C&D material generated from demolition of existing structures and river crossings should be sorted on-site into inert C&D material (that is, public fill) and C&D waste. Suitable areas should be designated within the works site boundaries for temporary stockpiling of C&D material. Within stockpile areas, the following measures should be taken to control potential environmental impacts or nuisance:

· covering material during heavy rainfall;

· locating stockpiles to minimize potential visual impacts; and

· minimizing land intake of stockpile areas as far as possible.