RO reject

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I was wondering If anyone can suggest a solution for using of Ro reject which has TDS of 12000 mg/l 

is it good for agricultural use for instance for Irrigation?

Thanks

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14 Answers

  1. In safely and continuously irrigating with saline water there are many considerations - water salinity, Sodium Adsorption Ratio, presence of contaminants e.g. Fluoride, maintaining hydraulic conductivity and structural integrity of selected soils for irrigation, capacity for adequate leaching of salts through and beyond the soil profile, adequate depth to closest aquifer to ensure nil/minimal impact on groundwater salinity. In Queensland there are coal seam gas water irrigation projects that have been safely irrigating agroecosystems involving salinity tolerant forests and grazed pastures at about 8 ML/ha/yr of 4000 uS/cm EC  / SAR 25 water for 12 year. Managing irrigation water and or soil water bicarbonate through sulphuric acid and gypsum pre-treatment of water to be pumped or regular soil application of agricultural grade gypsum and bentonite sulphur to soil surfaces, backed with regular soil monitoring, has been critical for success. These systems have involved Australian Soil Orders - Tenosols, Kandosols, Dermosols and Vertosols. Irrigating 12000 mg/L TDS water would require dilution with appropriate quantities of high quality surface or groundwater, ensuring all contaminants e.g. F fall within regulatory limits and that the proposed irrigation regime is modelled to ensure adequate leaching of applied salts through the soil profile and there will not be measurable impacts on underlying aquifer salinity. Depending on choice of crop plant foliar tolerance of irritant salinity may be less than for root uptake. This may cause preference for centre pivot drop tube  or drip irrigation versus sprinkler irrigation systems. In  Queensland flood irrigation of the above saline water would require a specific feasibility study and may be excluded under current regulatory guidelines.

  3. its not suitable for irrigation. For irrigation, TDS around 2000 mg/l is fine.

    Here you need to reduce TDS to this level to use. USe SWRO membrane and it will bring down to this. But yes it will be costly.

    If you want to reduce the cost, you can mix less TDS water with this one and try to bring TDS below 8000 mg/l. And after that, use BWRO membrane. 

    This way, you will get high recovery also.

     

     

  4. Day Hi from BKK Thailand. This is the terrible topic and still need the method to remove TDS. I have experience in Struvite which be generated after operated RO to recycle wastewater in cassava plant. There are mainly 3 ways, 

    Firstly, using this watewater for cooling tower.

    Secondly, using huge volume of treated wastewater to dilute.

    Thirdly, Create Struvite by using RO more than 3 time untill become to be crystallization.

    I would like to join this Project.

    aggasit2012@gmail.com

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  6.    Generally , only high salinity –Tolerant plants can be irrigated with concentrate of salinity higher than 2000mg/l.  Such plants  can not only tolerate high salinity but  also extract salt from the water and store it in its tissue or leaves.

     

      First of all, it is to be   ascertained whether there is a need for irrigation of water  for salinity tolerant vegetation nearby the site . It would be cost effective only if concentrate is blended with fresh water source or waste water to reduce its salinity to  levels acceptable for irrigation.

     

       There are plants can be grown using concentrate having  salinity  more than 2000mg/l ( In Middle East etc) .

     

     It also depends on site specific soil  conditions, effect on soil due to  the presence of Trace metals in the concentrate and its Toxicity if any caused by specific ion , and the impact on the  Ground water quality etc

     

     It needs a thorough  site specific study before taking a call.

     

     

  7. Not suitable for irrigation directly but with enough dilution can be used. The TDS is crude parameter for irrigation, better if you can get SAR.

  8. Is this SWRO, BWRO, Tile Water RO, what was the raw water source? This determines the quality of the reject water and its potential uses. Is the TDS salts NaCl), Se, other?

  10. Solution#1 You can reuse this water with another Sea Water RO Plant with a recovery upto 50 to 55%.

    Solution#2 You can reuse this water in combination with well / river water in this ratio (RO Reject:Well or River = 10/90). 

  12. what is the quantity of reject water per /hr and per day  ?  what is the % of system recovery ? 

    Let us know  .

  13. An indisputable and fail safe way to use the reject water is for flushing in a toilet. Have a toilet built or connect the reject water pipe to water tank of an adjacent toilet. 

    1 Comment

  14. If the reject has pressure energy,normally it is used to run energy recovery devices to reduce RO Power consumption.

    Not sure about using this high TDS water for agriculture