| 5.2d |
Better
Water Quality |
Our Responsibilities
Water Quality in 2004
Achievements in 2004
Our
Responsibilities
We aim to
ensure that the quality of our marine and freshwater is such that
the various conservation goals for them can be met, and that plans
are formulated and implemented to ensure Hong Kong's sewage systems
can operate safely and effectively both now and with future urban
development.
Water
Quality in 2004
Water quality
is monitored in rivers, beaches and marine waters to measure compliance
with Water Quality Objectives (WQOs) and protect the health of the
public and the environment. Over the past 15 years, there has been
much improvement in overall water quality, although some problem
areas still need addressing, such as western Victoria Harbour.
|
| Overall
water quality has been much improved over the past 15 years. |
In 2004:
| • |
87% of
marine water samples met WQOs, similar to that in 2003. |
| • |
82% of
river and stream samples met WQOs, similar to that in 2003. |
| • |
34 of 41
gazetted beaches (83%) met WQOs for bathing beaches, the same
as that in 2003. A breakdown of results in 2004 can be seen
at Table 1. The beach water guidelines are health-based. |
| Table
1 - Beach Water Quality in 2004 |
| Beach
rank |
Number
of beaches |
| Good |
25
(61%) |
| Fair |
9 (22%) |
| Poor |
5
(12%) |
| Very
Poor |
2
(5%) |
Achievements
in 2004
Harbour Area Treatment Scheme (HATS)
Regional Issues
Toxic Pollution
Other Water Issues
Some 6.2 million
Hong Kong people currently are served by public sewage treatment
systems, as seen in Figure 1.
Figure
1 - Areas served by public sewage treatment systems.
|
Harbour
Area Treatment Scheme (HATS)
Stage 1 of HATS
began operating in 2001 and significantly improved the water quality
in eastern and central Victoria Harbour. The next stage has been
widely debated. An
International Review Panel (IRP) of experts recommended several
options in 2000 (see Figure 2).
Figure
2 - Schematic map of HATS options. |
Detailed studies
of these options were completed in 2004 and the public was consulted
on the government's proposal as follows, with option A as
the prefered option:
| 1. |
|
Divide
the second stage into two phases.
In Stage 2A, the remaining 450 000 tonnes of untreated sewage
from Hong Kong Island would be given chemically-enhanced
treatment
(CEPT) plus disinfection at the existing treatment plant
on Stonecutters Island. Disinfection would also be applied
to the
Stage 1 sewage. In Stage 2B, a biological treatment plant
would be built, with the commencement date dependent on
trends in
water quality in the harbour and future sewage loads. Cost
is a consideration in this approach because it staggers
the $19.5
billion outlay required for all of Stage 2 (see Figure 3
- Breakdown of Costs). In any case, sewage charges will
have to increase. |
| Figure
3 – Breakdown of Costs. |
|
|
Capital
Cost
(HK$billion) |
Recurrent
Cost
(HK$billion per year) |
| Stage
2A |
8.4 |
0.44 |
| Stage
2B |
11.1 |
0.72 |
| Total |
19.5 |
1.16 |
| 2. |
|
Disinfect
sewage in Stage 2A.
The beaches at Tsuen Wan are strongly influenced by effluent
from Stage 1 of HATS. Bacteria in the effluent will need to
be adequately removed if these beaches are to be reopened. The
government proposes to do this through chlorination after the
CEPT process, but the treated effluent would need de-chlorination
before being discharged. An EIA will assess the effects of this
technique. |
| |
|
|
| 3. |
|
Build the
biological treatment plant underground, next to Stonecutters
Island.
The IRP recommended biological aerated filter treatment because
of its compactness. Studies found this technology could apply
in Hong Kong. |
| |
|
|
| 4. |
|
Keep sewage
treatment at one site.
Some people in the community have suggested using two or more
sites, but this was considered impracticable and costly. |
| |
|
|
| 5. |
|
Use
conventional contractual arrangements.
A design-build-operate contract could be suitable for treatment
plants, as it would expedite the delivery of the project. But
since the Drainage Services Department already operates the
Stonecutters Island plant, any application of the DBO approach
to Stage 2A would need more careful consideration of the interfaces
involved. The approach may be considered for Stage 2B. |
Consulting
the public
A five-month public consultation on HATS ended on 20 November 2004.
District Councils, green groups, academics, professional bodies,
business and industry groups, and legislators were consulted, and
an extensive community education programme was launched to encourage
the public to express their views.
Most comments
focused on the phasing proposal. Some concerns were expressed about
chlorination, others about the timing of Stage 2B. The government
will address chlorination in an EIA of the project, and will build
Stage 2B based on water quality trends after 2A is commissioned.
The government is now reviewing comments from the public and will
report to the Legislative Council in the first half of 2005.
Regional
Issues
The EPD is working
with the Shenzhen Environmental Protection Bureau on a programme
to review the Deep Bay Water Pollution Control Joint Implementation
Programme, aiming to complete the review in 2006.
The EPD is liaising
with the Guangdong Environmental Protection Bureau to develop a
water quality model for the Pearl River estuary. Data has been collected
and fieldwork completed, and the modelling contractor is now constructing
the model. The model should be ready by early 2006.
Toxic Pollution
A programme
to sample and test for toxic substances in the marine environment
was begun mid-2004 and will be conducted once a year. At the same
time, a biological indicator monitoring programme was begun to assess
the effects of pollution on the ecological health of the marine
environment.
China ratified
the Stockholm Convention on the reduction of persistent organic
pollutants in 2004 and this was extended to Hong Kong. Signatories
are required to draft an implementation plan. Hong Kong is now drafting
its plan, which will be included in China's National Implementation
Plan for submission to the Stockholm Convention Secretariat by November
2006.
| 
Trawling
for marine biota to obtain tissue for toxic substances analysis.
|
 |
The
Stockholm Convention is a global commitment to rid the world
of persistent organic pollutants.
|
Other
Water Issues
Funding approval
is being sought for a $14.5 million pilot effluent re-use scheme
at Shek Wu Hui. A high-level treatment unit will be added to the
existing secondary sewage treatment plant to produce high quality
reclaimed water for flushing, irrigation and water features in the
Sheung Shui area. The project is expected to begin operating in
2006 for a two-year trial.
An
in-house study on storm water pollution was completed. The study
focused on Mongkok and estimated that BOD loading equivalent to
12% of the sewage generated from the area ended up in storm water
drains. The pollution came from sewage from defective sewers, expedient
connections, and non-point source pollution such as street washing.
The findings indicate the need for a comprehensive approach to control
this problem.
Re-using
treated effluent wherever possible forms an essential component
of a holistic water management strategy. |
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