Page 22 - Industrial Wastewater Treatment, Recycling and Reuse

Industrial Wastewater Treatment, Recycling, and Reuse: An Overview 5

Figure 1.3 Water demand worldwide.

(Amarasinghe et al., 2007), the present industrial water consumption
accounts for 6%, which will increase to 8.5% in 2025 and >10%
( 18%) in 2050. Thus, in India, the major water consuming sector, as of
today and in the near future, is the agricultural sector. It is believed that
the production of most water-consuming crops, such as sugar cane, will
increase by 80% from 2000 to 2050 (water-intensive crops such as sugar
cane, rice, and food grains constituted 90% of India’s crop output in
2008). In a way, this can be advantageous for water recycling and reuse
because treated wastewater can be made suitable for agricultural use. This
is in contrast to the general view, discussed as part of this water recycling
and reuse theme, where the recycled water is intended to be used in the same
industry, either as processed water or for other utilities. Where water recy-
cling and reuse is practiced in Indian industry, the preference is for using
treated wastewaters for horticulture and gardening, while some industries,
such as the thermal power sector, use treated waters for ash handling. In
the mining industry, treated wastewaters can be used for washing ore. Apart
from pollution control, one of the main reasons for wastewater treatment is
the scarcity of water. In view of the growing water requirements for the agri-
cultural sector, a major water-consuming area, water for industry is going to
become scarcer and scarcer in the future. Just as in the rest of the world, the
major source of water for industry is surface water. In India, nearly 41% of
industries depend on surface water. Other sources of water include ground-
water ( 35%) and municipal water ( 24%) (see Figure 1.4).