AUES

To	Mr. Tang Hiu Yeung	Fax No	By email
Company	CRBC and Kaden Joint Venture
cc
From	T.W. Tam	Date	9 October 2015
Our Ref	TCS00670/13/300/F0134a	No of Pages	7	(Incl. cover sheet)
RE	Contract No. HY/2013/12 Tuen Mun - Chek Lap Kok Link

Northern Connection Toll Plaza and Associated Works Environmental Permit No.: EP-354/2009/D Investigation Report for Complaint of Milky Water from Drainage Outlet near Butterfly Beach, Tuen Mun on 2 September 2015

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Dear Sir, Enclosed please find the investigation report for the captioned for your follow up action. Should you have any queries or need further information, please do not hesitate to contact us or the

undersigned at Tel: 2959-6059 or Fax: 2959-6079.

Yours Faithfully, For and on Behalf of

Encl.

c.c. AECOM (ER) Mr. Roger Man By email ENVIRON (IEC) Dr. F.C. Tsang By email

Contract No. HY/2013/12 Tuen Mun - Chek Lap Kok Link - Northern Connection Toll Plaza and Associated Works

Investigation Report on Action or Limit Level Non-compliance

Complaint Log No.	TCS00670/13/300/F0134
Received Date by ET	7 September 2015
Complaint Details	The complainant complained that milky water was observed from drainage outlet to Butterfly Beach.
Complaint Location	Drainage outfall near the Butterfly Beach, Tuen Mun
Date of Complaint	2 September 2015
Environmental Aspect	Milky water
Complainant	Unknown
Complaint Route	via LCSD
Investigation Result	1 A complaint was received from the LCSD on 2 September 2015 regarding milky water discharged from the drainage outlet near the Butterfly Beach, Tuen Mun. It was suspected that the milky water was come from the site under the Contract. 2 According to the information provided by the CKJV, the relevant works areas adjacent to the concerned drainage pipes are proposed Manhole 5 (MH5) and proposed East Portal of underpass. On 2 September 2015, excavation of underpass by mechanical breaking was carried out at East Portal whilst and MH5 was idled. Construction water recycle system has been established for operation at underpass and no discharge of untreated water into the public drainage system is required. 3 Joint inspection has been carried out by EPD, AECOM and CKJV immediately receipt the complaint on 4 September 2015. During the inspection, no milky/ muddy water discharge was found at the potential works area. However, slightly leaking out of white water discharge was found at the concerned drainage outfall. Based on the investigation by CKJV, the incident may due to overload of WetSep after heavy rain on 2 September morning and the wastewater was not sufficiently treated before leaking out. 4 As remedial measures, CKJV proposed that all treatment wastewater generated from East Portal and associated areas will be diverted to TD2 area and discharge and all the natural stream water from upstream of the site would be bypassed so that it would not be contaminated by site activities. Moreover, sufficient sandbags and concrete bund has been enhanced around the cascade to prevent surface runoff from entering the cascade at East Portal. This remedial measures was implemented by the Contractor since 7 September 2015. 5 In effective from 8 September 2015, daily inspection of wastewater treatment facilities, concerned discharge points, drainage inlets and outlets would be carried out during typhoon or wet season. Moreover, a log which included cleaning records of wastewater treatment facilities would be maintained and incorporated into the EM&A reports.

Prepared By : T.W. Tam

Designation : Environmental Team Leader

Signature :

Date : 9 October 2015

Photo Record for mitigation measure