Water management plans that avoid intake of turbid water

ENTRY DATE: 15.11.2013 | LAST UPDATE: 15.11.2013

CATEGORIES:

  • Water Resources
  • Water intake, Purification

TECHNOLOGIES MATURITY:

Ready to be introduced

Technology Owners:

Hitachi Corporation

Needs Address

The need to mitigate the impacts of increased turbidity in water bodies in areas where rainfall patterns could change due to climate change (particularly, from extreme rainfall events). 

Adaptation effects

  • Control the lengthening of periods of water turbidity due to an increase in flooding, and control increases in water treatment costs. 
  • Improved wastewater treatment capacity to handle extreme events. 
  • Securing water resources to deal with water shortages resulting from climate change

Overview and Features

Rivers and streams fed by surface water can undergo a significant increase in turbidity under various rainfall conditions. Higher turbidity makes it necessary to increase the quantity of flocculants injected into water treatment processes.  By controlling the quantity of water intake during periods of high turbidity, it is possible to reduce the quantity of chemicals used and the amount of sludge produced in water treatment processes, thereby reducing environmental impacts and operating costs. But because the demand for water is unrelated to the variations in turbidity, however, it is preferable to reduce water intake during periods of high turbidity to the lowest level necessary to satisfy water demand.

There are two basic strategies underlying this approach. The first is to implement time-based strategies for water intake, drawing more water before and after periods of high turbidity. The second is to coordinate water intake among multiple water source systems. 

Avoiding water intake during times of high turbidity by timing water intake and linking watersheds by using distribution reservoir, control intake during times of high water turbidity, and compensate for reduced water availability by linking with other watersheds.

Source: Water Environment Simulations for Total Optimization of Water Management
Hitachi Group Solutions, Vol.91 No.08 634-635 (in Japanese)

Water volume strategies for timed water intake make use of the Quasi-optimal Routing System (QRS) method, utilizing water distribution ponds, and also incorporating strategies to control flow volume variations in order to minimize impact on water treatment processes. The QRS method converts flow volume calculations to a curve on a graph representing a defined region, and by making use of water stored in water distribution ponds, levels out pump operation, resulting in a simple yet effective method that allows operators to carefully plan the release of water flows volumes at the point of optimal efficiency. 

Cost

Energy source

Electricity

Ease of maintenance

This system must be operated in accordance with an operating manual.

Contact the manufacturer in the event of any problem. 

Technology performance

The case indicated below achieved a reduction in electricity costs of 2.89 million US dollars per year. 

Considerations

  • The coordination of water from different watersheds to avoid times of high turbidity can lead to an increase in electricity consumption in some cases.
  • Maximizing the reduction in environmental impacts can lead to significant imbalances in the rate of dependency on individual watersheds, and on facility operating ratios, potentially reducing stability of water supply.

Co-benefit, suitability for developing countries

This technology can also have the benefit of improving water quality. 

Information Resources

Water Environment Simulations for Total Optimization of Water Management (Hitachi Group Solutions, Vol.91 No.08 634-635 (in Japanese)).

http://digital.hitachihyoron.com/pdf/2009/08/2009_08_03.pdf