Seawater Desalination vs. Direct Potable Reuse

What are the key advantages and disadvantages of direct potable reuse as compared to seawater desalination for municipal water supply?

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Taxonomy

• Treatment
• Water Reuse & Recycling
• Desalination
• Sea Water Desalinisation
• Waste Water Reclaimation
• Water Supply
• Water Utility
• Water Supply Design
• Drinking Water Managment
• Water Management
• Urban Water Supply
• Drinking Water

6 Answers

1. There are two potable water reuse options currently gaining prevalence: direct potable reuse (DPR) and indirect potable reuse (IPR).While all water is eventually reused in some sense in a conventional water treatment system, DPR and IPR both involve a proactive decision to transform treated wastewater into drinking water.

   Advantages Of DPR

   Cost savings: Drinking water treatment and wastewater treatment typically occur in the same or nearby locations in DPR systems, requiring a short pumping distance for product delivery. The close proximity of both waste and drinking water treatment may present considerable cost savings for municipalities when compared to IPR methods, according to “Drinking Water through Recycling”, a report by the Australian Academy of Technological Science and Engineering (ATSE).

   Disadvantages Of DPR

   Additional setup: Some DPR systems may require additional water quality or process performance monitoring and/or an engineered storage buffer, according to the ATSE report. These items may increase costs and would require additional time, planning, and labor to implement. The purposes of a storage buffer include balancing variability between water production and water use, balancing water quality variability, and providing time to detect and respond to any contaminants in the water, according to the ATSE report.

   Advantages Of IPR

   Environmental Purification: In IPR, treated wastewater is discharged into an environmental system such as a river, lake, or aquifer. Some wastewater industry stakeholders believe that the time treated water remains in this environment system allows any remaining contaminants to be degraded by physical or biological processes, according to the ATSE report. Dilution of the water in the environment also may minimize any potential risk by decreasing the concentration of contaminants that may be present,

   Disadvantages Of IPR

   More expensive: IPR systems typically have higher capital and operational costs, according to the ATSE report. The construction and maintenance of transfer systems to move the water from the treatment facilities to a suitable environmental buffer can also be costly. Many IPR systems rely on extensive enclosed pipelines and associated pump stations to deliver water from the water treatment facility to the environmental buffer. Additional costs come from pumping water long distances, especially

   regards,

   Prem Baboo

   
   

   
   

2. The key advantage of direct potable reuse as compared to seawater desalination for municipal water supply is Environmental Impact. As there is no brine discharge in the sea, there will not be any impact on the sensitive aquatic life. Also, direct potable reuse actually reuse the wastewater, which will have positive impact on the environment.

   However, the key disadvantage is psychological factor. People don't want to drink treated sewage, however, astronauts do.

3. Dear Nikolay,

    

   It is all about ‘Demand and Supply’; many parts of the world are devoid with fresh water resource, so whatever source available in the region has to be used to meet the drinking water needs considering the cost. If alternatives are available, cost, advantages and disadvantages can be analysed.

    

   Almost all the projects have advantages and disadvantages. If there is no other water resource available in the region to meet the drinking water needs and the only option available is desalination. With some disadvantages, the plant has to operate to meet the need; this will be the biggest advantage of the project.

    

   Regards,                                                                                                                                               

   Dr.D.Siddaramu

4. Desalination=3-4 KwhDirect potable reuse= 1,6kWh Havent got time to go into much more detail today,but important to note that DPR is becoming a reality in many cities/countries around the globe (Inc.Us,Aus,Singapur,África and growing in number as more successful experiences are observed worldwide). i can't see the future of many overcrowded cities around the globe without DPR for simple survival or in order not to annihilate their economies.Currently,up to 30%of total potable supply is expected to be with DPR in the above mentioned countries before 2025. High tech ensures high wster quality standards,and Blending takes the "yuk" factor away.

5. I would reply with a hated "it depends". Treated waste water is already there, in many cases with a discharge quality good enough to be used in general purposes. Desalination would imply new facilities and an additional spend of energy. In addition, location and proposed are needed to have a better overview of possibilities.

6. Hi, Nikolay
   

   Hard to answer. It all depends on the amount of resource and on the use of the resource. The disadvantages of desalination are quite clear: the costs. It requires an important initial investment. Also, maintenance costs are high as well. An alternative to reduce the maintenance is to desalinate brackish groundwater, as one gets rid of problems like entraintment or impingement of marine life and gains the soil's natural attenuation. The advantage is also clear: the resource is unlimited and its quality is more than acceptable, even for drinking purposes. Treating waste-water is cheaper, but the amount of treated efluents is generally smaller than that of a desalination plant. In addition, the quality of the treated fluid is generally poorer than that of desalinated water. If the purpose is to use it for irrigation, then it's fine (with some tolerance). As for drinking, I would never use treated waste water.
   

   And that's my opinion...
   

   Cheers
   

   Andres
   

   1 Comment

   1. Andres, are you sure that you never drank treated waste water? Have you heard about the water cycle? The river Rhine in Germany wich starts in switzerland and reaches the sea in the Netherlands has been drunken approx ten times on ints way.....means that the water works alongside the river are distributing "ex-waste water" to the public. anyway why would we need to drink treated waste water? there are plenty of other ways to utilize this ressource. However I generally agree with your statement. If you look at the figures about how little desalinated water is actually consumed by humans and how much is used for other purposes....Recharge the aquifer with treated effluent this is practised since decades in orange county and in Belgium at least.

      1 Comment reply

      1. Hi, Ulrich
         
         I fully agree with your post. It all depends on the definition for waste water. Is that rejected drink-water or the usually "dark" effluent of a treatment station. Thanks for the data about the Rhein. Certainly, I'm sure I'm nowadays drinking water from there :-).