High Efficiency Reverse Osmosis is a reverse osmosis technology specially designed to treat high silica and difficult to treat wastewater
Hero, a Reverse Osmosis (RO) based process, is specially designed to treat aggressive feed waters. Constituents which often pose problems to conventional RO processes are handled with ease by Hero. Examples of these constituents are biological matter, oil and grease, and silica. By effectively preventing these constituents from being a root cause to membrane scaling, the Hero process offers the operator and end users Higher recoveries and operational benefits. Both of these lead to reduces cost through:
Less Water Consumption
Less Use of Anti-Scalants
Less Cleaning Required
In a R/O process, feed water of high TDS is pressurized against a semi-permeable membrane. Part of the feed water permeates through this membrane and is of low TDS (total dissolves solids or salts) due to the rejection of salts by the membranes. The remaining part of the water is designated as reject and is of high TDS. Thus, RO operation results in concentration of salts in the reject stream. Limitations of a Conventional RO Process When designing an RO system, the natural saturation limits of various salts should not be exceeded, otherwise these salts would precipitate and scale the RO membranes. Silica is the most common process limiting constituent. At most commonly found conditions of 77F and pH between 6.5 to 7.5, the solubility of silica is 120 ppm. If silica in reject water exceeds more than 120 ppm under the above conditions, scaling of membranes would occur. Thus, if feed water has Silica of 50 ppm, maximum concentration possible under normal conditions of conventional RO would be reached within just 2 cycles of concentration. This would translate into a possible permeate recovery of approximately 50% from the feed water.
The hero process (compared to a conventional RO system), is designed to increase the Silica solubility in the RO reject water to 1500 ppm and beyond. With the increased solubility, recoveries beyond 90% can be successfully achieved, under the conditions previously described.
As I have posted earlier pretreatment to keep scale forming species zero and operating at high PH makes the HERO inceases the complexity and increases the Capex and OPEX. There are new RO Technokogies like closed circuit RO , Extreme RO, Rotec RO etc. have addressed many of the scaling, fouling , operation , process control issues reliably and they are field proven. Conventional RO process is 40 years old and they have severe limitations and inefficient. The time has come to bury the conventional RO and adopt new disruptive technologies. New process technology allows inline cleaning of membranes automatically.
i used design it two times . it is a good technology .we need to treat all of the hardness to zero , and control the PH like 10~11 to make the RO system to work . now your RO usually works in 90~95 % recovery.
if you want to discuss with me more , you can sent email to : moonandbaby@163.com , i'm chinese.
RO membranes are same but pretreatment approach is a bit different. Pretreatment system is designed to remove completely all scale forming impurities dissolved in water as well the feed water pH is alkaline so that silica scaling is prevented on membrane when operating at high PH. Very careful selection of pretreatment process , operation and monitoring is critical to the sucess of the HERO process. All the advantages of high recovery with HERO process is nullified with waste water from pretreatment regeneration -ex- water softners, dealkalisers etc. HERO process is outdated. Now RO process technologies have changed with new disruptive RO process technologies it is possible to reach as high as 98% recovery .
Toray BW membranes also used, 1st step weak cation exchange, CO2 removal (MDG) pH increase to around 9,5 than 1st RO , pH correction to pH 6 to 7, 2nd pass RO, RO concentrate from 2nd pass mixed before 1st pass RO.