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SECTION
5 ASSIMILATIVE CAPACITY CAPITAL STOCK
| 5.3 |
Assimilative
Capacity of Freshwater Systems |
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| 5.3.2.5 |
As
well as physical schemes and programmes
for improved sewerage and sewage treatment,
a number of regulatory instruments have
been introduced by the Hong Kong SAR Government
in recent years to address water pollution
problems. The key pollution control legislation
enacted and its relevance to, and effects
on, assimilative capacity of freshwaters
to date are briefly reviewed in Box 5.3a.
| Box
5.3a Regulation in Hong Kong Affecting
Freshwater Pollution |
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The
Water Pollution Control Ordinance
(Cap 358) provides for the designation
of water control zones within which
discharges of effluent other than
domestic sewage into a foul sewer
must be licensed (by EPD). First enacted
in 1980 and subsequently amended to
tighten controls on waste water discharge
procedures, the Ordinance has allowed
for better regulation and control
of polluting activities within the
various WCZs so that EPD can work
towards achievement of the WQOs in
marine and freshwaters, through regulation,
enforcement and advice. It is estimated
that through enforcement activities
in 1997 alone, a total daily reduction
in BOD loadings of 1,330kg was achieved
(equivalent to a reduction in organic
pollution load from 112,700 people).
The
Waste Disposal Ordinance (Cap 354)
provides the framework for managing
all solid and semi-solid wastes in
Hong Kong. With regard to freshwater
pollution, it prohibits livestock
keeping in urban areas, provides for
control over the discharge or deposit
of livestock waste in designated control
areas, controls the illegal dumping
of waste and introduced a control
scheme on chemical waste. Two subsidiary
schemes of particular relevance to
freshwater pollution control are described
here.
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The
Livestock Waste Control Scheme
(LWCS) was introduced under the
Waste Disposal (Livestock Waste)
Regulations to address the problem
of organic and faecal pollution
of rivers and streams from agricultural
activities. The LWCS set up Livestock
Waste Prohibition Areas in which
the keeping of livestock was prohibited
and outside of these areas further
controls on the collection, storage,
treatment and disposal of livestock
waste was enforced. Livestock
farmers were provided with payments
to assist with developing acceptable
waste management procedures and
free waste collection systems
were set up. The scheme has been
successful in reducing livestock
waste pollution of watercourses
(up to 80% reduction in BOD loadings
to rivers in the New Territories),
although some of the changes have
resulted from widespread cessation
of farming activities: prior to
scheme implementation in 1988
there were around 10,000 livestock
farms - which reduced to less
than 800 in 1997 (see Section
3.3 for a discussion of agricultural
land use change).
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The
Chemical Waste Control Scheme
(CWCS) was brought about under
the Waste Disposal (Chemical Waste)
(General) Regulation. The scheme
has resulted in the reduction
of toxic discharges to rivers
through controls on the management,
transport, handling and disposal
of hazardous and toxic wastes.
In particular, the development
of the Chemical Waste Treatment
Centre (see Section 3.5) has provided
a secure and effective disposal
route for chemical waste arisings.
Sources:
EPD (1998c), EPD (1999c), WWF (1999).
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| 5.3.2.6 |
As
a result of the implementation of the WPCO
and WDO, significant reductions in BOD loadings
to freshwaters have been achieved. These
reductions, together with current loadings
(at the end of 1998) are shown in Table
5.3d.
| Table
5.3d Organic Pollution Load Reduction
in Freshwaters ( Point Source Discharge) |
Table
5.3d Organic Pollution Load Reduction in
Freshwaters ( Point Source Discharge)
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Pollution
Source
|
BOD
load before control (kg day-1) |
BOD
load after control (kg day-1) |
BOD
load reduction
(kg day-1) |
BOD
load reduction
Average % |
| Tolo
Harbour & Channel WCZ |
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| DICI(2) |
11,860 |
2,644 |
9,216 |
78% |
| Livestock |
2,856 |
0 |
2,856 |
100% |
| Southern
WCZ |
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| DICI |
15 |
0 |
15 |
100% |
| Livestock |
178 |
0 |
178 |
100% |
| Port
shelter WCZ |
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| DICI |
1,023 |
550 |
473 |
46% |
| Livestock |
158 |
0 |
158 |
100% |
| Junk
Bay WCZ |
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| DICI |
482 |
277 |
205 |
43% |
| Livestock |
19 |
1 |
18 |
95% |
| Deep
Bay WCZ |
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| DICI |
20,095 |
4,432 |
15,663 |
78% |
| Livestock |
67,187 |
3,208.5 |
63,978.5 |
95% |
| North
Western WCZ |
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| DICI |
7,118 |
719 |
6,399 |
90% |
| Livestock |
9,520 |
0 |
9,520 |
100% |
| Western
Buffer WCZ |
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| DICI |
4.6 |
0.2 |
4.4 |
96% |
| Livestock |
n/a |
n/a |
- |
- |
| Victorial
WCZ |
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| DICI |
81 |
35 |
46 |
57% |
| Livestock |
n/a |
n/a |
- |
- |
| DICI
total |
40,678.6 |
8,657.2 |
32,021.4 |
79% |
| Livestock
total |
79,918 |
3,209.5 |
76,708.5 |
96% |
| Overall
total |
120,596.6 |
11,866.7 |
108,729.9 |
90% |
Notes:
(1) BOD load after control is equivalent
to current (1998) BOD loading.
(2) DICI - Domestic, Industrial, Commercial
and Institutional. BOD loading reductions
in DICI sources are attributed to Water
Pollution Control Ordinance (WPCO); BOD
loading reductions in livestock waste sources
are attributed to Waste Disposal Ordinance
(WDO).
Source: EPD (1999c)
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| 5.3.2.7 |
As
well as indicating those WCZs which are
subject to the greatest organic pollution
loads to rivers and streams, the data in
the table show that particularly large reductions
in wastes from livestock sources have been
achieved as a result of the Waste Disposal
Ordinance (and LWCS). The Deep Bay WCZ has
experienced particularly large reductions
in pollutant inputs, although the current
levels of BOD loadings to rivers in this
catchment are still significant.
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| 5.3.2.8 |
Infrastructure
for the treatment of water supplied to homes,
businesses and industry in Hong Kong is indirectly
relevant to the assimilative capacity of the
natural capital. Whilst much of Hong Kong's
water is supplied from the mainland, measures
to reduce leakages, foster efficiency, manage
demand, and increase the supply network for
seawater flushing will indirectly benefit
assimilative capacity through reduced water
abstraction (see Section 3.4 - Freshwater
Resources for further discussion on freshwater
supply and demand). |
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