6 Sewerage and Sewage Treatment Implications

6.1 Introduction

6.1.1.1 This section presents an assessment on identification of the potential sewerage impact of the increase in visitors in Lei Yue Mun waterfront area arising from the completion of the waterfront enhancement works for Lei Yue Mun. The assessment of local sewerage networks and treatment capacity of sewage treatment plant are also carried out and relevant mitigation measures are proposed to mitigate any identified adverse sewerage impact.

6.1.1.2 The Study Area is located at the Lei Yue Mun waterfront area which includes substantial areas of Lei Yue Mun Village, Ma Wan Tsuen, Che Ting Tsuen, Ma Pui Tsuen, On Li Sai Tsuen and up to Lei Yue Mun Praya Road.

6.2 Description of the Environment

6.2.1.1 Lei Yue Mun is located within the catchment of Kwun Tong Preliminary Treatment Works (KTPTW). The KTPTW sewerage catchment has an approximate area of 1,810ha and an existing population of approximately 930,000. The proposed Project is located at the waterfront of Lei Yue Mun. The land uses within the Study Area are mainly residential uses, restaurants and shops in village houses and squatters.

6.2.1.2 According to the latest public sewerage record plan, there is only limited public sewerage system laid up to the end of Lei Yue Mun Praya Road outside Lei Yue Mun Village. The existing villages including substantial areas of Lei Yue Mun Village, Ma Wan Tsuen, Che Ting Tsuen, Ma Pui Tsuen, On Li Sai Tsuen and etc. with a population of about 2,419 which are within the unsewered area. With the new sewerage system and dry weather flow interceptor, the polluted flow from the existing stormwater system will be intercepted and hence the water quality and hygiene conditions of the area would be improved. The existing sewerage network at Lei Yue Mun is shown in Figure 6.1.

6.2.1.3 Lei Yue Mun Ma Wan Public Toilet cum Bathhouse is located adjacent to the basketball court near Ma Wan Tsuen as shown in Figure 6.2. According to the as-constructed drawings, the existing public toilet is equipped with a sewage treatment system to treat the sewage of the public toilet and bath house before discharging to the sea.

6.2.1.4 Other existing public toileting facilities are located outside the Study Area. They are summarized below:

i) Ling Nam Sun Tsuen Public Toilet located near the roundabout of Lei Yue Mun Path.

ii) Public Toilet at Lei Yue Mun Market inside the Lei Yue Mun Municipal Services Building at Lei Yue Mun Path.

iii) Public Toilet at Lei Yue Mun Sports Centre inside the Lei Yue Mun Municipal Services Building at Lei Yue Mun Path.

iv) Public Toilet at Lei Yue Mun Library inside the Lei Yue Mun Municipal Services Building at Lei Yue Mun Path.

6.2.1.5 Based on site inspection, some seafood restaurants and shops have constructed their own septic tanks and grease traps to treat the oily or greasy food wastes.

6.3 Design Guidelines and Standards

6.3.1 General

6.3.1.1 The design guidelines and standards adopted in this assessment are:

(a) DSD Sewerage Manual Part 1 (2013 Version);

(b) DSD Sewerage Manual Part 2 (2013 Version);

(d) EPD Guideline for Estimating Sewage Flows for Sewage Infrastructure Planning Version 1.0 (Report No. EPD/TP 1/05);

(e) Environmental Impact Assessment Ordinance (EIAO), Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM), Annex 14 Section 6.5.

6.4 Sewage Estimation and Impact Assessment

6.4.1 Estimation of Existing Sewage Flow

6.4.1.1 According to the visitor counting surveys conducted in August 2016 and the overseas visitor figures by sea provided by the Tourism Commission (TC), the average monthly visitation to Lei Yue Mun waterfront area is estimated to be 39,970 visitor/month.

6.4.1.2 The existing units and population figures in the Study Area are adopted with reference to the latest site investigation, desktop study of flow monitoring survey and walk around survey of con-current project in the Study Area which are summarized in Table 6.1.

Table 6.1 Existing Developments and Population Figures in the Study Area

Description of Unit	Total No. of the Unit / Flat	Population per Unit / Flat	Population / Employee
Squatter or Village House	691	3.5⁽¹⁾	2,419
Seafood Restaurant	18	12⁽²⁾	216
Seafood Shop	33	2⁽³⁾	66
Retailed Shop	43	2⁽³⁾	86
Visitor	-	-	1,332⁽⁴⁾

(1) According to the traditional village houses in Kwun Tong District in Table 5.2 of Census and Statistics Department (CSD)’s latest Population By-census.

(2) Assumed 8 waiters and 4 cooks per restaurant on average by Review of Provision of Sewerage System in Lei Yue Mun Village – Feasibility Study.

(3) Assumed 2 employees per shop on average by Review of Provision of Sewerage System in Lei Yue Mun Village – Feasibility Study.

(4) Existing monthly visitation to the Study Area is taken to be 39,970 head/month (i.e. 1,332 head/day).

6.4.1.3 In accordance with Table T-1 and T-2 of EPD’s Technical Paper (Report No. EPD/TP 1/05), unit flow factor of squatter or villager is taken to be 0.15m³/person/day. Unit flow factor of employee in seafood restaurant is taken to be 0.08 + 1.5 = 1.58m³/person/day and unit flow factor of employee in seafood shop and retail shop is taken to be 0.08 + 0.20 = 0.28m³/person/day. It is also assumed that unit flow factor of visitors is taken to be 0.02m³/person/day. Therefore, the average dry weather flow of the Study Area is summarized in Table 6.2

Table 6.2 Existing Total Average Dry Weather Flow in the Study Area

Description of Unit	Population / Employee (person)	Unit Flow Factor (m³/person/day)	Average Dry Weather Flow (m³/day)
Squatter or Village House	2,419	0.15	362.9
Seafood Restaurant	216	1.58	341.3
Seafood Shop	66	0.28	18.5
Retailed Shop	86	0.28	24.1
Visitor	1,332	0.02	26.6
		Total	773.4

6.4.1.4 As shown in Table 6.2, the existing total average dry weather flow generated from the Study Area is 773.4 m³/day. The sewage contribution from the visitors is approximately 3.4% of the total average dry weather flow.

6.4.2 Ultimate Sewage Flow Estimate

6.4.2.1 PlanD’s 2011 – based TPEDM planning data was referenced to for forecasting the population in Lei Yue Mun area in 2036. It is noted that the total population in Lei Yue Mun area in 2011 (including residents in LYM Estate) is 14,050 heads and the total population in 2036 is projected to 17,950 heads. The growth rate is reckoned to be 27.8%.

6.4.2.2 Referring to the employment trend in Lei Yue Mun area from 2011 to 2036, there is a decrease in employee in accordance with the TPEDM. This may be due to the redevelopment of industrial building to residential building in Yau Tong areas. However, it is known that with the increase in visitors in Lei Yue Mun, the commercial and food & beverage activities will be enhanced with additional workforce. Therefore, on the conservative side, the growth rate of employee is assumed to be the same as the growth rate of residents in Lei Yue Mun area (i.e. 27.8%) in the assessment.

6.4.2.3 The number of visitation to Lei Yue Mun waterfront area in 2036 is projected based on natural growth of the tourist and tourist figure provided by TC which is estimated to be 53,470 visitors/month. The ultimate total daily flow is shown in Table 6.3.

Table 6.3 Ultimate Total Daily Flow in the Study Area

Description of Unit	Ultimate Population / Employee (person)	Unit Flow Factor (m³/person/day)	Base Flow Factor*	Ultimate ADWF (m³/day)
Squatter or Village House	3,092	0.15	1.34	621.5
Seafood Restaurant	277	1.58	1.00	437.7
Seafood Shop	84	0.28	1.34	31.5
Retailed Shop	110	0.28	1.34	41.3
Visitor	1,782	0.02	1.00	35.6
		Total		1,167.6

* Base flow factor of 1.34 is adopted to account for stormwater flow into the sewerage networks at the DWF interceptors to be constructed in by DSD under Lei Yue Mun Village Sewerage project.

6.4.2.4 With ultimate development scenario after completion of the waterfront enhancement works, it is reckoned that the ultimate total average dry weather flow of Lei Yue Mun area is 1,167.6 m³/day. The sewage contribution from the visitors is approximately 3.0% of the total average dry weather flow. The sewage flow generated from the additional visitors can be handled by the upgraded Kwun Tong Preliminary Treatment Works. The upgrading works of Kwun Tong Preliminary Treatment Works is discussed in Section 6.4.4.

6.4.3 Impact Review on Existing Sewerage Network and the Proposed Sewerage Improvement Works

6.4.3.1 With reference to the estimated sewage flow prepared under Lei Yue Mun Village Sewerage project, the estimated sewage flow in 2036 is at the same order to the estimated flow in Table 6.3. Therefore, the proposed additional sewerage networks under Lei Yue Mun Village Sewerage project involving installation of gravity sewers, rising mains and sewage pump sumps in Lei Yue Mun, upgrading of the existing sewers and Sam Ka Tsuen pumping chamber and etc. would be adequate to cater for the estimated ultimate flow in Lei Yue Mun even after the completion and commissioning of the Lei Yue Mun Waterfront Enhancement Project in 2036.

6.4.3.2 Options evaluation for implementation of sewerage interim measures has been conducted by DSD under Lei Yue Mun Village Sewerage project and eventually no sewerage interim measure is proposed. Therefore, it is not required to assess the impact arising from the sewerage interim measure to be constructed by DSD.

6.4.4 Impact Assessment on Treatment Capacity of KTPTW

6.4.4.1 Due to various intensive development in Kwun Tong sewerage catchment such as Kai Tak Development, Anderson Road Quarry Development, development of ex-Cha Kwo Ling Kaolin Mine Site and etc. that constituted an increase in the sewage discharge to the existing KTPTW, DSD has commenced the Investigation, Design and Construction project namely “Agreement No. CE47/2013(DS) – Upgrading of Kwun Tong Preliminary Treatment Works (KTPTW) – Investigation, Design and Construction” project to upgrade the existing KTPTW.

6.4.4.2 Under this project, the current planned design treatment capacity of KTPTW will be upgraded from 10.93m³/s (944,352m³/day) to 13.13m³/s (1,134,432m³/day) which has taken into account the planned increase in population of various development in Kwun Tong district. The increase in visitors after the completion of the waterfront enhancement works will lead to an increase of the sewage flow from 26.6m³/day to 35.6 m³/day. The increase in sewage flow generated from the visitors in Lei Yue Mun (i.e. 9 m³/day x 8(peaking factor)) is only 0.006% of the upgraded treatment capacity (1,134,432m³/day) of KTPTW. It is therefore concluded that the sewage flow at Lei Yue Mun in ultimate development scenarios after completion of the waterfront enhancement works will not pose adverse sewerage impact to the treatment capacity of KTPTW.

6.4.5 Impact Assessment on Programme Gap between this Project and Sewerage Improvement Works by DSD

6.4.5.1 The tentative construction programme of the waterfront enhancement works by CEDD, waterfront enhancement works by ArchSD and Lei Yue Mun Village Sewerage project are shown in Table 6.4. It is also noted that the construction programme of sewerage improvement by DSD under Lei Yue Mun Village Sewerage project is prepared based on the latest information given by DSD that the construction work will commence in Q3 of 2018 for completion in Q1 of 2023. The Lei Yue Mun Waterfront Enhancement Project will only be commissioned upon completion of DSD’s project in Q1 2023. Therefore, the additional sewage generated from Lei Yue Mun Waterfront Enhancement Project will be collected by the newly constructed sewage system. The proposed sewerage improvement works under Lei Yue Mun Village Sewerage project is shown in Figure 6.2.

Table 6.4 Tentative Construction Programme of Lei Yue Mun Waterfront Enhancement Works and Lei Yue Mun Village Sewerage Project

Contract

2018

2019

2020

2021

2022

2023

Waterfront Enhancement Works by CEDD

(Q3 2019-Q4 2021)

Waterfront Enhancement Works by ArchSD

(Q3 2019-Q1 2023)

Lei Yue Mun Village Sewerage project by DSD

(Q3 2018-Q1 2023)

6.4.5.2 In accordance with the latest construction programme, no programme gap is envisaged between the Lei Yue Mun Waterfront Enhancement Project by CEDD/ArchSD and the new sewerage networks by DSD. Hence, any sewerage plug-in and additional sewage arising from the increase in visitors will be discharged into the newly constructed sewerage system. Nevertheless, CEDD/ArchSD will closely coordinate with DSD in monitoring the programme of the two projects and liaise with DSD to formulate mitigation measures including but not limit to installation of chemical toilets near the restaurants to cater for the additional sewage arising from the increased visitors after commencement of the Lei Yue Mun Waterfront Enhancement project and before the commissioning of the proposed sewerage works under Lei Yue Mun Village Sewerage project should any programme gap is identified in the future.

6.4.6 Impact Assessment and Mitigation Measures to the Existing Public Toilet

6.4.6.1 As presented in Sections 6.4.3 and 6.4.4, the assessment concluded that the increase in visitors after completion of the waterfront enhancement works will not pose adverse sewerage impact to the major sewerage infrastructures. This section will carry out assessment on the adequacy of provision of toileting facilities to cater for the increase in visitors.

6.4.6.2 At present, almost all arriving visitors either by land (dropping off at public transport interchange near the Municipal Services Building) or by sea (dropping off at Sam Kam Tsuen Ferry Pier or Sam Ka Tsuen Public Landing Steps – KP15) will need to walk along Lei Yue Mun Path get into the Study Area. Along their walking journey, there are two existing public toileting facilities (i.e. public toilets in Lei Yue Mun Municipal Services Building and Ling Nam Sun Tsuen Public Toilet) that could be used by the arriving visitors. It is assumed that those visitors will use these two toilets before entering the Study Area.

6.4.6.3 Upon completion of the new landing facility, as a conservative approach, visitors travelling to the Study Area by sea are assumed to utilise the new landing facility. According to the visitor count surveys conducted in August 2016 and the tourist figure provided by TC, the average monthly visitation to the Study Area by sea in 2016 is estimated to be 4,710. The projected visitation in 2036 taking into account natural growth of visitors and tourist figure provided by TC is estimated to be 10,460 indicating a net increase of 5,750 visitors/month. These visitors are assumed to use the existing Ma Wan Tsuen Public Toilet and the private toilets in restaurants and shops within the Study Area. It is assumed that 80% of the visitors will use the public toilet and 20% of the visitors will use the private toileting facilities in nearby restaurants and shops etc. The net increase of visitors using the Ma Wan Tsuen Public Toilet is estimated to be 4,600 visitors/month.

6.4.6.4 After considering the peaking factor of visitors in weekend, the maximum increase in visitors per day using Ma Wan Tsuen Public Toilet is shown below:

Assuming ratio of visitors in weekend to weekday = 2:1

Additional visitors in weekday per day after Lei Yue Mun Waterfront Enhancement Works

= 4,600 / [22 + 8(2)] (assuming there is 22 weekdays and 8 weekends in each month)

= 122 visitors /weekday (i.e. 61 male visitors/weekday and 61 female visitors/weekday)

Additional visitors in weekend per day after Lei Yue Mun Waterfront Enhancement Works

= 122 x 2

= 244 visitors/weekend (i.e. 122 male visitors/weekday and 122 female visitors/weekday)

6.4.6.5 The existing Ma Wan Tsuen Public Toilet cum Bath House was built in 1980s’. In accordance with the as-built drawings, total 12 nos. of toilets + 7 nos. of urinal + 4 nos. of sink for male and 12 nos. of toilets + 5 nos. of sink for female and 1 no. of disable toilet were constructed. A septic tank with biological filter was also constructed for treatment of sewage from the above-mentioned facilities and bath house and the treated sewage will be infiltrated away by open joint clay pipe network.

6.4.6.6 The existing toilet and bath house with the sewage treatment facilities are currently operated and maintained by FEHD. It is noted that the internal arrangement of the toilet was altered several times to enhance comfort and to fulfil the then-latest toileting layout standard. Comparison between the original as-built layout and the current layout of toilet is shown in Table 6.5. It is noted that the number of fitment for both male and female has been reduced but the sewage treatment facilities have remained unchanged. The hygiene condition of the existing toilet is considered satisfactory. Photos of the existing toilet and bath house are shown in Appendix 6.1.

Table 6.5 Existing Sanitary Fitments at Ma Wan Tsuen Public Toilet and Bath House

Gender	Toilet & Bath House Layout	No. of Water closet (WC)	No. of Urinal (U)	No. of Wash Basin (WB)	No of Bath Apartment	Sewage Treatment Facilities
Male	80’s Layout	12	7	4	10	Remain Unchanged
Male	Current Layout	8	6	6	8
Female	80’s Layout	12	0	5	10
Female	Current Layout	9	0	6	8

6.4.6.7 Two head count surveys for the public toilet at Ma Wan Tsuen were carried out on both weekday (5th Oct 2016) and weekend (9th Oct 2016). The surveys started at 6:30 am and ended at 11:30 pm (Total 17 hours). According to the survey, the peak time for both female and male toilets usage was around 4:00pm to 7:00pm. The total daily users of public toilet are shown in Table 6.6:

Table 6.6 Total Daily Users of Public Toilet in Head Count Surveys

Gender		Weekend	Weekday
Male	Total (per day)	470	90
Male	Average (per hour)	28	6
Female	Total (per day)	433	151
Female	Average (per hour)	26	9

6.4.6.8 The peak hourly utilisation rate is shown in Table 6.7.

Table 6.7 Peak Hourly User Rate in Head Count Surveys

Gender	Weekend	Weekday
Male	66 (4pm to 5pm)	17 (10am to 11am)
Female	64 (4pm to 5pm)	19 (5pm to 6pm)

6.4.6.9 The existing toilet and bath house were basically designed for serving the local residents as well as visitors at Lei Yue Mun. Based on the head count surveys and Section 6.4.6.7, the provision of toilet facilities is sufficient to meet the existing needs. In accordance with Building Regulations (Standards of Sanitary Fitments, Plumbing, Drainage Works and Latrines) Cap. 123 sub. leg. I, Tables 17, 18 and 19, the minimum number of water closet, urinal and wash basin required to cater for the current population of head count survey is shown in Table 6.8.

Table 6.8 Estimation of Existing Usage of Public Toilet

Gender	Toilet & Bath House Layout	No. of Water closet (WC)	No. of Urinal (U)	No. of Wash Basin (WB)
Male	Provided (1)	8	6	6
	Required (Weekday)	1	1	1
	Required (2) (Weekend)	3	2	3
	Min. Surplus of Existing (1) –(2)	5	4	3
Female	Provided (3)	9	0	6
	Required (Weekday)	3	0	1
	Required (4) (Weekend)	6	0	3
	Min. Surplus of Existing (3) –(4)	3	0	3

Note: The operation hours of visitor attractions are assumed to be 9:00am to 10:00pm (total 13 hours) as the duration of head count survey conducted is 17 hours. A discount factor of 13/17 = 0.76 is adopted for estimation of WC, U and WB.

6.4.6.10 As described in Section 6.4.6.3, there is expected to be an increase in visitors using Ma Wan Tsuen Public Toilet after the completion of waterfront enhancement works. The required number of water closet, urinal and wash basin to cater for the additional visitors with the head count survey is summarized in Table 6.9.

Table 6.9 Estimation of Toileting Facilities required for Additional Visitors

Gender	Toilet & Bath House Layout	No. of Water closet (WC)	No. of Urinal (U)	No. of Wash Basin (WB)
Male	Min. Surplus of Existing	5	4	3
	Required (Weekday)	1	1	1
	Required (Weekend)	1	1	1
Female	Min. Surplus of Existing	3	0	3
	Required (Weekday)	3	0	1
	Required (Weekend)	3	0	1

Note: (1) The ratio of Male: Female of the additional visitors is assumed to be 1:1.

(2) No. of WC, U and WB required are estimated in according to Building Regulations (Standards of Sanitary Fitments, Plumbing, Drainage Works and Latrines) Cap. 123 sub. leg. I, Tables 17, 18 and 19.

6.4.6.11 It is reckoned that the facilities of existing public toilet are able to cater for the use of the additional visitors after the completion of the waterfront enhancement works. No modification works on toileting facilities of the existing Ma Wan Tsuen toilet are required. The above assessment adopted a worst-case scenario where all additional visitors by sea will only use the Ma Wan Tsuen Public Toilet and the toileting facilities of restaurants/shops in the Study Area. However, there is another public toilet namely Lei Yue Mun Ling Nam Sun Tsuen Public Toilet located adjacent to the roundabout of Lei Yue Mun Path which could be used by visitors but has not been considered when performing the above utilisation assessment. Furthermore, other toilet facilities are also provided at the Lei Yue Mun Municipal Services Building as shown in Figure 6.1. It is expected that the majority of visitors by sea will use the Ma Wan Tsuen Public Toilet as they are expected to use the new landing facility to arrive at Lei Yue Mun while the visitors by land will utilise the public toilets at Ling Nam Sun Tsuen and Lei Yue Mun Municipal Services Building.

6.4.6.12 The treatment capacity of the existing septic tank and biological filter at Ma Wan Tsuen Public Toilet are expected to be able to handle the sewage from the visitors. As described in Section 6.4.5, there is no programme gap envisaged between the Lei Yue Mun Waterfront Enhancement Works by CEDD/ArchSD and the new sewerage networks by DSD. Under the Lei Yue Mun Village Sewerage project by DSD, a sewage pump sump will be constructed adjacent to the existing public toilet and bath house such that the existing sewage treatment system constructed for the public toilet can be decommissioned and sewage from the public toilet and bath house can be discharged by gravity directly into the pump sump. Therefore, additional sewage arising from the increase in visitors after commissioning of the public landing facility can be collected by the new sewerage system. However, if the connection to the new sewerage system constructed by DSD cannot be commissioned in time due to unforeseen reasons, short-term mitigation measures such as temporary toilets will be provided. As referred to Section 6.4.6.10, a total 4 numbers of WCs (Male and Female) are required for the additional visitors. Therefore, total 4 nos. of temporary chemical toilet are proposed to be erected and these chemical toilets can be removed upon the public sewers have been in place and the existing sewage treatment facilities for the toilet have been decommissioned.

6.4.6.13 As described in Section 6.4.6.2, visitors by land are expected to use the public toileting facilities at Lei Yue Mun Municipal Services Building and Ling Nam Sun Tsuen Public Toilet. The additional visitors by land using these toileting facilities is 7,750 visitor/month and corresponding daily visitors (weekend) is therefore 408 visitors/day (i.e. 31 visitors/hour, assumed visitors will go to Lei Yue Mun from 9:00am to 10:00pm). The number of water closet, urinal and wash basin provided in the existing toileting facilities are summarized in Table 6.10. With regard to the total number of toileting facilities provided at Lei Yue Mun Municipal Services Building and Ling Nam Sun Tsuen Public Toilet, the increase in flow and utilisation rate of the existing toileting facilities arising from the additional visitors after completion of waterfront enhancement work is considered to be insignificant.

Table 6.10 Number of WC, U and WB at Lei Yue Mun Municipal Services Building (LYMMSB) and Ling Nam Sun Tsuen Public Toilet (LNSTPT)

		Gender	No. of Water closet (WC)	No. of Urinal (U)	No. of Wash Basin (WB)
LNSTPT		Male	4	8	4
LNSTPT		Female	7	0	4
LYMMSB	LYM Market	Male	3	3	3
	LYM Market	Female	4	0	4
	LYM Public Library	M/F	1	1	1
	LYM Sport Centre 2/F	Male	4	4	4
	LYM Sport Centre 2/F	Female	5	0	4
	LYM Sport Centre 4/F	Male	4	4	4
	LYM Sport Centre 4/F	Female	5	0	4
		Total	37	20	32

6.5 Conclusion

6.5.1.1 It was predicted that after the completion of Lei Yue Mun Waterfront Enhancement Works, the additional monthly visitation to the Study Area will be about 13,500 in 2036. With the existing visitors, the total number of visitors after Lei Yue Mun Waterfront Enhancement Works is estimated to be 53,470 visitors/month in 2036.

6.5.1.2 The existing total average dry weather flow of the Study Area is 773.4m³/day. The sewage contribution for the visitors is 26.6m³/day, which is approximately 3.4% of the total average dry weather flow generated in the Study Area. The ultimate total average dry weather flow of the Study Area after the completion of the waterfront enhancement works is 1,167.6 m³/day. The sewage contribution for the visitors is 35.6m³/day, which is approximately 3.0% of the total average dry weather flow.

6.5.1.3 The increase in sewage discharge arising from the increase in visitors after commissioning of the landing facility in Lei Yue Mun will not pose adverse sewerage impact in ultimate scenario upon completion of the sewerage improvement works by DSD under Lei Yue Mun Village Sewerage project.

6.5.1.4 The total sewage flow generated from the visitors in Lei Yue Mun after the completion of the waterfront enhancement works will not pose adverse sewerage impact to the treatment capacity of KTPTW.

6.5.1.5 The head count survey for the utilisation rate of the existing Ma Wan Tsuen Public Toilet cum Bath House was conducted and it is verified that the current number of water closet, urinal and washing basin are sufficient and the surplus water closet, urinal and washing basin are adequate to cater for usage of the additional visitors after waterfront enhancement works.

6.5.1.6 According to the latest construction programme, no programme gap is envisaged between the Lei Yue Mun Waterfront Enhancement Works by CEDD & ArchSD and the new sewerage networks constructed by DSD. Hence, any sewerage plug-in and additional sewage arising from the increase in visitors will be discharged into the newly constructed sewerage system. Nevertheless, CEDD/ArchSD will closely coordinate with DSD in monitoring the programme of the two projects and liaise with DSD to formulate mitigation measures including but not limit to installation of chemical toilets near the restaurants to cater for the additional sewage arising from the increased visitors after commencement of the Lei Yue Mun Waterfront Enhancement project and before the commissioning of the proposed sewerage works under DSD project should any programme gap is identified in the future.