Why Shall We Recycle Water ?

kishan

Emmanuel TROUVE Patrick HOFFMANN
Board of Directors General Manager
NOVA-VIA S.A. NOVA VIA LLC
  Email: p.hoffmann@novavia.lu

Bottom-line

Every economy needs energy and water.

Fact The management of water resources in the Middle East and North Africa region is likely to become far more challenging because of irregular periods of rainfall and rapidly growing economies and populations.

Consequence
A lack of natural water resources especially in populated and arid regions with a high demand of fresh water.

Opportunity

Recycling and reusing water for planned beneficial uses is particularly attractive as it can limit or eliminate sewage discharges whilst generating alternative resources.


Total Renewable Water Resources in m3 per Capita, by Country



Source: Aquastat, 2011

Other possible reasons motivating water recycling are:

  • A low quality of available fresh water: citizens & industries need to secure not only the quantity but also the quality of water for their various needs and applications.
  • A better cost-efficiency of on-site (decentralized) water recycling solutions compared to conventional (centralized) treatment plants: public strategies increasingly focus on solutions to decrease costs related to water infrastructures. On site recycling could reduce both, Capital Expenditures (CapEx) as well as Operating Expenses (OpEx).
  • Can you imagine a city without water? Decentralized solutions are the most efficient protection against hostile threats on water on a city or a state level.


It’s Time To Reduce Weaknesses Of Conventional Centralized Systems

Conventional centralized systems produce and distribute drinking water through a vast water network. The resulting waste water is ideally transferred through waste water networks and treated in centralized treatment plants. This conventional system has a number of disadvantages such as:

1. The need for an overproduction of drinking water to compensate significant losses in fresh water networks (due to leakages). Solution: Recycling 70% of water at the point of use reduces water stress by more than 50% without reducing the users’ comfort & usage.

2. The need for high amounts of disinfectant (usually chlorine) against microbial contamination in networks. Disinfection ensures an adequate quality of water at the point of use but impacts on health and environment have to be considered. Solution: Recycling of water with membrane technology - an absolute physical barrier to particles that are larger than the membrane pore size – to considerably reduce the amounts of chemicals.

2. A) Operation & maintenance costs - O&M - of water networks amount to 65 – 80% of the total O&M costs of centralized systems.



B) High CapEx of large water pipelines to distribute water to major consumers such as hotels & industries (located far from the centralized water production plant). In general, CapEx of water & waste water networks amount to 60% - 75% of the total CapEx of water & waste water infrastructures. This negatively impacts the environmental footprint of water management of a region.

Solution: Recycling up to 80% of water on site reduces CapEx and O&M of water & waste water infrastructures.



Certainly, some disadvantages of conventional water and wastewater systems could be reduced by repairing water network leakages, implementing monitoring programs of chemicals, or incorporating semi-centralized systems (”satellites”) – if a limitation of damages is the strategy.

However, with increasing restrictions on conventional water resources and wastewater discharges as well as availability of fresh & clean water, recycling and reuse has become an essential tool in terms of an integrated & efficient water management scheme. As a result, this growing dependence on reuse makes it critical to integrate water recycling & water reuse programs.

Are Existing Water Recycling Systems Good Enough?

In Japan, USA and some other countries, it is common practice to recycle greywater (waste water from wash hand basins, showers and baths) on site. Despite the fact that water prices in MENA region tend not to reflect its scarcity value, some Arab countries such as UAE, Israel, Jordan, and Tunisia have moved aggressively to promote wastewater reuse.

Although most recycling devices are producing high quality recycled water, the energy requirements remain high; i.e. more than 5 kWh per m3 – a hidden cost. But what does that actually mean?

I. Lower water bills but higher energy bills. Recycling 200 m3 per day of water in Dubai translates into additional AED 146,000 per year in electricity expenses; i.e. additional AED 1.5 Mio over 10 years.

II. Lower water footprint - a better resource management - but increasing CO2 emissions.

As a result, conventional recycling technologies translate into only a minor improvement in the overall environmental footprint.



High Quality Recycled Water Is Now Available With Low Energy

Doubtless, new policies, Government strategies and public awareness campaigns will promote on site water recycling. New innovative low energy solutions – a key factor in water recycling - will thereby increase the number of decentralized recycling units – an ecological and profitable investment. This also translates into lower Government expenses related to water management whilst developing new markets on a national level. In summary, the benefits of recycling water with low energy are multiple:

  • Reducing the pressure on water resources.
  • More intensive and efficient use of water.
  • Producing highest water quality whilst minimizing OpEx.
  • Lowering Government expenses on water management whilst developing new markets.
  • Self-sufficient because recycled water is produced on site.
  • Use of internal energy of waste water to achieve recycling rates > 70%.
  • Optimized water flow and energy consumption due to an advanced process monitoring & control.
Thus, managing the precious resource of water efficiently means recycling water into high quality with low energy delivering greater value with less input!
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