Appendix 4.4     Fixed Plant Noise Impact Assessment
The Plant Inventories of Proposed Disinfection Facilities at Stonecutters Island Sewage Treatment Work
	Treatment Units	No of item	Reference	SWL, dB(A)	Total SWL , dB(A)
Proposed Dechlorination Plant
Chemical Feed Pump		2	Ref 1	109	112
Chemical Transfer Pump (20L/s)		1	Ref 5	92	92
(from truck to tank)
Tank Transfer Pump (20L/s)		1	Ref 5	92	92
(from tank to tank)
Sampling Pump		2	Ref 1	109	112
(from chamber 15 to simulation loop)
Ventilation Fan for Plant Room		3	Ref 3	83	88
Sump Pump (2L/s)		2	Ref 5	92	95
Air Conditioner Unit for Control Room		2	Ref 4	78	81
Fume Recovery System		1	Ref 6	96	96
Proposed Chlorination Plant
Chemical Transfer Pump (10L/s)		3	Ref 5	100	105
(from truck to tank)
Chemical Transfer Pump (70L/s)		1	Ref 5	92	92
(installed on the vessel)
Tank Transfer Pumps (20L/s)		1	Ref 5	92	92
(from tank to tank)
Transfer Pump to Day Tank (20L/s)		1	Ref 5	92	92
Sump Pump (2L/s)		2	Ref 5	92	95
(sodium hypochlorite tank farm)
Effluent Transfer Pump to Mixing Tank		1	Ref 1	109	109
Chemical Dosing Pumps		2	Ref 1	109	112
Sump Pump (Barge Unloading Area) (2L/s)		1	Ref 5	92	92
Sump Pump (Day Tank Farm) (2L/s)		2	Ref 5	92	95
Air Conditioner Unit for Control Room		2	Ref 4	78	81
Existing Stonecutter Island Sewage Treatment Plant			Ref 2	112	112
	Notes:
	Ref 1: As the flow rate of the pump is subject to dosing plan which is not available at this stage, the maximum SWL of the pumpset in Good Practice on Pumping System Noise Control (GPPSNC) was used in this assessment for the worst case.
	Ref 2: The SWL for the operation of the exisitng sewage treatment plant was backward calculated based on the on-site measured noise level using the standard acoustical principles.
	Ref 3: Based on the estimated volume flowrate by DSD, the SWL of the ventilation fan was made reference to Good Practices on Ventilation
	System Noise Control.
	Ref 4:  Based on on-line searching (http://www.fujitsugeneral.co.nz/includes/heat-pumps/conventional-window-wall.pdf), the SWLs of air
	conditioner units range from 69 to 78 dB(A) depending on the cooling capacity. The maximum SWL of the air conditioner unit was used
	in this assessment for the worst case.  It should be noted that Fujitsu air-conditioner was only taken as an example for the purpose of
	this assessment.
	Ref 5: Based on the estimated horsepower and operating speed of pumpset by supplier, the appropriate SWL of the pumps was made
	reference to Good Practice on Pumping System Noise Control (GPPSNC).
	Ref 6: The estimated SWL was made reference to EIA Report on San Wai STW and Ha Tsuen Pumping Station.

Calculation of Operational Noise Levels at Representative Noise Sensitive Receiver (Unmitigated Scenario)
Calculation of Operational Noise Levels at NSR N1
	Treatment Units	No of item	Reference	SWL, dB(A)	Total SWL , dB(A)	Distance in m	Enclosure Reduction, dB(A)	Screening Reduction, dB(A)	SPL , dB(A)	Enclosed	Remark
Proposed Dechlorination Plant
Chemical Feed Pump		2	Ref 1	109	112	155	20		43	Yes	2duty+1standby
Chemical Transfer Pump (20L/s)		1	Ref 3	92	92	140			44	No	1duty+1standby
(from truck to tank)
Tank Transfer Pump (20L/s)		1	Ref 3	92	92	150			43	No	1duty+1standby
(from tank to tank)
Sampling Pump		2	Ref 1	109	112	175	20		42	Yes	2duty+2standby
(from chamber 15 to simulation loop)
Ventilation Fan for Control Room and		2	Ref 5	83	86	140			38	No
Chemical Transfer Pump Room
Ventilation Fan for Chemical Feed Pump Room		1	Ref 5	83	83	155			34	No
Sump Pump (2L/s)		2	Ref 3	92	95	140			47	No
Air Conditioner Unit for Control Room		2	Ref 2	78	81	140			33	No
Scrubber		1	Ref 4	96	96	130			49	No
								Total SPL, dB(A) at N1	53
	Notes:
	GWTM : The assumed SWL of the ventilation fan was made reference to the Techical Memorandum on Noise From Construction Work Other Than Percussive Piling.
	Ref 1: As the flow rate of the pump is subject to dosing plan that is not available at this stage, the maximum SWL of the pumpset in Good Practice on Pumping System Noise Control (GPPSNC) was used in this assessment for the worst case.
	Ref 2:  Based on on-line searching (http://www.fujitsugeneral.co.nz/includes/heat-pumps/conventional-window-wall.pdf), the SWLs of air conditioner units range from 69 to 78 dB(A)
	depending on the cooling capacity. The maximum SWL of the air conditioner unit was used in this assessment for the worst case. It should be noted that Fujitsu air-conditioner was only
	taken as an example for the purpose of this assessment.
	Ref 3: Based on the estimated horsepower and operating speed of pumpset by supplier, the SWL of the pumps was made reference to Good Practice on Pumping System Noise Control (GPPSNC).
	Ref 4: The estimated SWL was made reference to EIA Report on San Wai STW and Ha Tsuen Pumping Station.
	Ref 5: Based on the estimated volume flowrate by DSD, the SWL of the ventilation fan was made reference to Good Practices on Ventilation System Noise Control.
	Enclosure Reduction: Reduction of SWL due to the enclosure for the equipment
	* Standby item was not inlcuded in the noise assessment

Calculation of Operational Noise Levels at Representative Noise Sensitive Receiver (Unmitigated Scenario)
Calculation of Operational Noise Levels at NSR P1
	Treatment Units	No of item	Reference	SWL, dB(A)	Total SWL , dB(A)	Distance in m	Enclosure Reduction, dB(A)	Screening Reduction, dB(A)	SPL , dB(A)	Enclosed	Remark
Proposed Chlorination Plant
Chemical Transfer Pump (10L/s)		3	Ref 4	100	105	330		10	39	No	3duty+3standby
(from truck to tank)
Chemical Transfer Pump (70L/s)		1	Ref 4	92	92	230		10	30	No
(installed on the vessel)
Tank Transfer Pumps (20L/s)		1	Ref 4	92	92	315		10	27	No	1duty+1standby
(from tank to tank)
Transfer Pump to Day Tank (20L/s)		1	Ref 4	92	92	315		10	27	No	1duty+1standby
Sump Pump		2	Ref 4	92	95	315		10	30	No	2duty+2standby
(sodium hypochlorite tank farm)
Effluent Transfer Pump to Mixing Tank		1	Ref 1	109	109	520	20	10	20	Yes	1duty+1standby
Chemical Dosing Pumps		2	Ref 1	109	112	520	20	10	23	Yes	2duty+1standby
Sump Pump (Barge Unloading Area)		1	Ref 4	92	92	240		10	29	No
Sump Pump (Day Tank Farm)		2	Ref 4	92	95	520		10	26	No
Air Conditioner Unit for Control Room		1	Ref 3	78	78	305		10	13	No
Existing Stonecutter Island Sewage Treatment Plant			Ref 2	112	112	330		10	47
								Total SPL, dB(A) at P1	48
	Notes:
	GWTM : The assumed SWL of the ventilation fan and actuator was made reference to the Techical Memorandum on Noise From Construction Work Other Than Percussive Piling.
	Ref 1: As the flow rate of the pump is subject to dosing plan that is not available at this stage, the maximum SWL of the pumpset in Good Practice on Pumping System Noise Control (GPPSNC) was used in this assessment for the worst case.
	Ref 2: The SWL for the operation of the exisitng sewage treatment plant was backward calculated based on the on-site measured noise level using the standard acoustical principles.
	Ref 3:  Based on on-line searching (http://www.fujitsugeneral.co.nz/includes/heat-pumps/conventional-window-wall.pdf), the SWLs of air conditioner units range from 69 to 78 dB(A)
	depending on the cooling capacity. The maximum SWL of the air conditioner unit was used in this assessment for the worst case. It should be noted that Fujitsu air-conditioner was only
	taken as an example for the purpose of this assessment.
	Ref 4: Based on the estimated horsepower and operating speed of pumpset by supplier, the SWL of the pumps was made reference to Good Practice on Pumping System Noise Control (GPPSNC).
	Enclosure Reduction: Reduction of SWL due to the enclosure for the equipment
	Screening Reduction: Reduction of SWL due to the screening of line of sight by the structure of FSD diving training centre itself.
	* Standby item was not inlcuded in the noise assessment