Project Title : Harbour Area Treatment Scheme (HATS) – Provision of Disinfection Facilities at Stonecutters Island Sewage Treatment Works


Reference of the Approved EIA Report in the Register : AEIAR-113/2007

Conditions of Approval under Section 8(3) of the EIA Ordinance (the Ordinance)



1.      The Applicant shall put in place a control mechanism on the dosage of sodium hypochlorite and sodium bisulphite in the disinfection process to avoid over-dosage and adverse environmental impacts on water quality and marine ecology.


2.      The Applicant shall conduct a close to real time on-line monitoring on the dosage of sodium hypochlorite and sodium bisulphite as well as total residual chlorine (TRC) concentration at the inlet chamber to the submarine outfall and marine water quality.


3.      The quality of the effluent discharging (including but not limiting to pH, biochemical oxygen demand, suspended solids, E. coli, TRC and Chlorination by-products (CBPs)) into the inlet of the submarine outfall shall meet the discharge limits to be established by the EPD.


4.      The monitoring programme during the operation phase should be enhanced on the marine water quality for chemical parameters on TRC and CBPs as well as the whole effluent toxicity tests having regard to international best practices for similar large-scale disinfection facilities.  The monitoring schedule shall be enhanced by increasing the frequency of tests and subject to a period of review.  The monitoring reports shall be put on a designated website.


5.      The Applicant shall report the results of the monitoring to the Advisory Council on the Environment on a quarterly basis.


6.      The Applicant shall put in place an emergency response plan to deal with deviation of monitoring results from the predictions in respect of water quality and marine ecological risk.


7.      The set of further information submitted by the Applicant on 31 October 2007 under Section 8(1) of the Ordinance shall form part of the approved EIA report, and shall be placed on the Ordinance Register and the Ordinance website (



Environmental Protection Department

November 2007