|
Water pollution through natural processes is
insignificant in Nepal. Domestic sewage and industrial effluents are
the major contributors of water pollution. Haphazard urbanisation and
inadequate sewerage facilities have accelerated the discharge of
domestic liquid wastes without any treatment. Almost all the urban
areas have no wastewater treatment facilities. The cumulative effects
of wastewater discharge have a striking negative impact, particularly,
in the rivers flowing through the Kathmandu Valley. The holy river
Bagmati is biologically dead due to discharge of such domestic and
industrial wasters, particularly in the stretch flowing through urban
areas.
Biological contamination is generally noticed in
the supplied drinking water as well. Frequent incidence of water-borne
diseases indicates the deterioration of the drinking water quality in
both urban and rural areas.
Although the contribution of the manufacturing
industries to the gross domestic product (GDP) is estimated to be
around 10 per cent, most of them discharge the effluents and solid
wastes without any treatment. According to the latest Census
(1996//97) of industries, the number of establishments and persons
engaged in all VDCs were about 1,594 and 92,344 as against 1,963 and
1,04,364 in all Municipalities. Compared to the previous 1991/92
Census, carpet and rugs, garments, bricks, distilleries and printing
establishments have decreased in numbers during 1996/97 Census.
With a concentration of 56.76 per cent of total
manufacturing establishments, the Central Development Region (CDR) is
found to be the most busy region in manufacturing activities. The
region shares 70.54 per cent of the total employees, and 73.04 per
cent of total wages and salaries. It has also shared 76.04 per cent of
the total value added with 66.84 per cent of input and 70.5 per cent
of the total output.
In contrast to the CDR, the Far-Western Development
Region (FWDR) shares only 3.74 per cent of the total number of
manufacturing establishments.
Localised industrial pollution is also on the rise.
Wastewater is directly discharged on to the terrestrial and aquatic
systems without any treatment. The wastewater generally contains a
high load of oxygen demanding wastes, disease causing agents,
synthetic organic compounds, plant nutrients, inorganic chemical and
minerals, and sediments (Devkota and Neupane, 1994). Total industrial
wastes have been estimated at 0.076 million tons of TSP, 8.557 million
cubic meter of wastewater, 5.7 thousand tons of BOD, 9.6 thousand tons
of TSS and 22 thousand tons of solid wastes. Industrial TSP release in
the Kathmandu Valley exceeds the total load discharged in all other
development regions. A recent sample survey of 36 industries
throughout the Kingdom revealed that the population equivalent (PE) of
industrial effluent ranges from 416 to 9,540 (Devkota, 1997; Table
2.8.3). It is generally accepted that local human PE is about 50 gram
per day.
Table 2.8.3 Characteristics of Industrial
Wastewater
|
Maximum observed
values
|
| Sector/source |
Sample
size |
pH |
Conductivity
(ms/cm) |
Salinity |
Temp |
|
TDS |
BOD |
COD |
TSS |
O/G |
PE |
| |
(.
/.) |
(0C) |
|
(mg/l) |
(mg/l) |
(mg/l) |
(mg/l) |
(mg/l) |
|
| Iron
and steel galvanizing |
| Pickling
waste |
3 |
1.54 |
2.39 |
1.1 |
44.4 |
2850 |
|
n.a |
96 |
30 |
n.a. |
|
| Soap
manufacturing |
|
|
|
|
|
|
|
|
|
|
|
|
| Combine
final outlet |
3 |
14 |
153 |
220 |
43.8 |
174800 |
|
8220 |
33500 |
17400 |
90 |
822 |
| Pulp
and paper |
2 |
|
|
|
|
|
|
|
|
|
|
1713 |
| Black
liquor |
|
10.4 |
39 |
25.2 |
32.9 |
31350 |
|
32450 |
13600 |
15200 |
2200 |
|
| White
liquor |
|
9.34 |
1290* |
1.9 |
35.7 |
9000 |
|
1824 |
9833 |
2044 |
50 |
|
| Vegetable
oil/ghee |
|
|
|
|
|
|
|
|
|
|
|
|
| Neutralization
wash |
4 |
9.08 |
4.1 |
4.1 |
48.8 |
10850 |
|
4717 |
5320 |
5350 |
580 |
2000 |
| Textile |
| Combine
final outlet |
4 |
6.36 |
2210* |
0.1 |
33.4 |
2210 |
|
732 |
5750 |
140 |
9.8 |
4392 |
| Brewing |
| Combine
final outlet |
2 |
8.04 |
521* |
0.1 |
29.4 |
278 |
|
514 |
725 |
90 |
n.a |
1542 |
| Distillery
Spent wash |
1 |
4.4 |
18.13 |
10.9 |
84.5 |
18550 |
|
13040 |
54000 |
11230 |
n.a |
9540 |
| Beverage/soft
drink |
|
|
|
|
|
|
|
|
|
|
|
|
| Combine
final outlet |
3 |
9.05 |
2.7 |
1.3 |
33.2 |
1236 |
|
196 |
300 |
66 |
1.4 |
720 |
| Food
processing |
|
|
|
|
|
|
|
|
|
|
|
|
| Combine
final outlet |
3 |
4.91 |
863* |
0.2 |
36.7 |
350 |
|
2372 |
3800 |
1200 |
12.4 |
1423 |
| Leather
tanning |
| Combine
final outlet |
3 |
13.58 |
3 |
1.4 |
29 |
9900 |
|
1035 |
6500 |
8267 |
1230 |
1035 |
| Carpet
dyeing |
4 |
|
|
|
|
|
|
|
|
|
|
1142 |
| Light
spent dye bath |
|
4.71 |
2.62 |
1.4 |
84.2 |
1072 |
|
648 |
860 |
280 |
4.2 |
|
| Dark
spent dye bath |
|
4.82 |
5.08 |
2.8 |
82.1 |
3595 |
|
2208 |
2300 |
400 |
5.8 |
|
| Carpet
washing |
4 |
|
|
|
|
|
|
|
|
|
|
416 |
| Sulfuric
acid + bleaching |
1.02 |
21.6 |
13.1 |
27.1 |
1200 |
|
184 |
456 |
672 |
4 |
|
| Caustic
soda wash |
14 |
10.4 |
6 |
28.6 |
4531 |
|
230 |
540 |
320 |
8.7 |
|
| Sulfuric
acid wash |
1.07 |
19.87 |
12 |
28.1 |
4115 |
|
210 |
620 |
294 |
5.5 |
|
| Detergent
wash |
2.53 |
2.85 |
1.4 |
28.1 |
316 |
|
207 |
330 |
132 |
4.3 |
|
Source: Devkota, 1997 Note : TDS: total dissolved solid; BOD:
biological oxygen demand; COD: chemical oxygen demand; . TSS: total
suspended solid; O/G: oil and grease; PE: population equivalent. *
unit in ms/cm
Although urbanisation and industrial development is
at an infancy stage, water pollution is rapidly increasing in most of
the areas of the country, both in urban and rural areas. Water quality
is degraded through the discharge of untreated domestic wastewater and
industrial effluents. Continued efforts are required to minimise
pollution load through the enforcement of pragmatic standards for
specific types of industries, provision of incentives for use of
cleaner technologies, and effluent treatment facilities. Industries
should also be promoted to comply with the environmental regulatory
measures. Industrial operators should also be encouraged to minimise
the waste load through good house keeping practices, appropriate water
management, stocking of required raw materials, optimum use of
chemicals, and adoption of recovery and reuse process and complying
with discharge standards |
