Efficient use of water resources

The “International Conference on Water and Waste Water Management” as part of AchemAmerica will provide leaders and decision makers in governments, industries, research institutions, and other concerned organizations on how chemical engineering can help solve water-related problems in industry and municipalities.
In the past 45 years Mexico’s water resources have decreased by more than 60% down to 4500 m3 per capita and year (p.c./a). By 2020 resources are expected to decline by a further 25%. Besides the continuous rise in population (2% p.a.) and the marked trend towards urbanization, the situation has been aggravated by the extremely disparate distribution of water. While there are sufficient resources in the south, the industrialized urban areas of the interior, the north and north-west actually only have about 2000 m3 p.c./a at their disposal. In highly stressed regions like Valle de Mexico the figure is less than 200 m3 p.c./a. Thus many of Mexico’s commercial centers are already hovering between imminent and extreme (<500 m3 p.c./a.) water scarcity.

The total annual water requirement of about 78 billion m3 is mainly caused by agriculture with 73%, municipal water supply with 17% and industry with 5%. By 2025 water consumption is expected to increase by further 48%, with the lion’s share going to industry (+65%). As municipal and industrial growth will affect urban areas most, this will intensify the need for sustainable concepts for water treatment and recycling.
In urban areas the connection rate of municipal water supply is currently close to 95%, in rural areas about 68%. The most common treatment technology is sand filtration followed by chlorination. The quality of potable water often fails to meet drinking water standards. Thus in many regions there can be no guarantee of a clean water supply.
Surface water and municipal wastewater are of growing importance as water resources for the industry. Thus there is a considerable need for efficient technologies to produce process and utility water.
The volume of wastewater is mainly determined by the public sector and industry. At the municipal level, the volume is more than 7 billion m3 p.a., of which only about 18% is treated. This is due to insufficient capacity, poor maintenance and operation of sewage plants.
The amount of industrial wastewater of more than 5 billion m3 p.a. is mainly generated by sugar production (27%), chemistry & oil (12%), iron & steel (2.6%), paper & cellulose (2.6%), food & beverages (2.4%) and textiles (1.7%). Only about 15% of the industrial wastewater is treated. Only 42% of the treatment facilities have a biological step. Only very few plants are equipped with a third treatment step. Over half of the plants in operation fail to fulfill the legal requirements.
On account of this situation almost 75% of Mexico’s surface waters are polluted. The state of groundwater resources, especially in urban areas, is also critical. Excessive water consumption is accompanied by the qualitative impact of wastewater irrigation and leaking sewage systems (40%). The critical state of Mexico’s water resources in turn adversely affects municipal and industrial water consumption.
In the future, due to decreasing raw water quality and ever dwindling resources industry will be increasingly forced to boost its investments in raw water treatment and in closing process water cycles. There is a tremendous need for investment, especially in industrial wastewater treatment.
Over the next few years the Comision Nacional del Agua (CNA) has US$ 2016.5 million available for renewing water and wastewater systems, of which 15–20% have already been invested in specific programs. In line with the international trend towards privatization of the water and wastewater market Mexico is intensifying her activities to integrate commercial companies into her water services.