Comparison of desalinated water treatment methods

If the quality of fresh water is good, with a conductivity of less than 1000 and a salt content of less than 700, it can be treated using an anion-exchange bed, a cation-exchange bed, or a mixed-bed system; this approach results in low costs, high recovery rates, and water quality that meets the required standards. If the conductivity of fresh water is greater than 1000, reverse osmosis is generally used as the pretreatment system for mixed-bed systems. Of course, the investment in reverse osmosis systems is high, and the operating costs are also high. Moreover, the water production rate is generally only around 75%, which is much lower than that of the process using resin exchange exclusively. It depends on the quality of your fresh water.

I would like to know the specific figures for the cost per ton of water, investment, and water production rate.

Well, I guess it varies from design firm to design firm, and from equipment supplier to equipment supplier. Based on a capacity of 100 t/h, if the treatment process involves reverse osmosis plus mixed-bed filtration, the investment is estimated to be around 9 million yuan; if only anion and cation exchange beds are used, the investment will not exceed 5 million yuan. As for operating costs, differences are significant due to variations in water quality and processing methods. With the reverse osmosis + mixed-bed process, the operating cost (for chemicals and electricity) is around 0.4 yuan. The efficiency of the full-bed process is roughly similar, but there is a significant difference in water production rate: the full-bed process achieves at least 90%, whereas the reverse osmosis process only reaches 75%. It still depends on the quality of fresh water; if the water quality is good, there’s no need to use reverse osmosis.

Generally, the initial investment for reverse osmosis is slightly higher, the operating costs for the anion and cation exchange beds are high, and the cost components vary depending on the quality of water; moreover, the water produced by reverse osmosis is free from pollution! Generally, it’s better to combine them, depending on your water quality requirements!

I just did a search; please refer to this post, original poster: http://bbs.hcbbs.com/viewthread.php?tid=65070

Under normal circumstances, the treatment using cationic and anionic resins is less costly; our company has conducted calculations for new projects

Keep learning*; there’s really a lot to learn about demineralized water

Ion exchange resin still has a lower treatment cost, but many new projects I’ve seen these days use reverse osmosis combined with electrodeionization to treat boiler make-up water

Our company’s desalinated water production system is designed using a process of mechanical filtration + reverse osmosis + mixed-bed filtration, with a capacity of 2*45 t/h