The Zero Liquid Discharge ROWTP was installed at the Texas Golf Course community, commissioned and has been operating for several months. The original system design had called for three reverse osmosis trains followed by evaporators to reduce the already low quantity of concentrate water to a solid sludge. The sludge was to be hauled off to a solid waste landfill.
While the plant was still in the construction phase the facility was granted a permit to discharge the concentrate to the municipal sewer system. This was a fortunate event because it eliminated the need for the evaporator system which would have cost approximately $1M plus annual operating cost of approximately $1M.
The ROWTP has been operating satisfactorily and is producing high quality water for irrigation. Daily product water production is 911,500 gallons. Daily concentrate production is 19,728 based on 24/7 operation. Overall system recovery is 97.5%. The membrane systems are arranged in three stages. The second and third stage trains utilize concentrate water as their feed source.
Fortunately there arose only one problem which was result of the feed water well and not the process equipment. The feed water chemistry has developed some undesirable qualities that were not reported in the original analysis. These parameters include high SDI’s, high levels of BAC and higher silica, iron levels, which were reported as satisfactory or nonexistent in the original analysis. As a result the third stage cannot be operated at the present time due to membrane fouling. So currently total systems concentrate water has increased from 22 gallons to 44 gallons, thereby decreasing the total recovery from 97.3% to 94%. Recovery is still very impressive compared to the industry standard maximum of 85%. The feed water quality issues are currently being addressed and once resolved, the third train will be reinstated.
While the plant was still in the construction phase the facility was granted a permit to discharge the concentrate to the municipal sewer system. This was a fortunate event because it eliminated the need for the evaporator system which would have cost approximately $1M plus annual operating cost of approximately $1M.
The ROWTP has been operating satisfactorily and is producing high quality water for irrigation. Daily product water production is 911,500 gallons. Daily concentrate production is 19,728 based on 24/7 operation. Overall system recovery is 97.5%. The membrane systems are arranged in three stages. The second and third stage trains utilize concentrate water as their feed source.
Fortunately there arose only one problem which was result of the feed water well and not the process equipment. The feed water chemistry has developed some undesirable qualities that were not reported in the original analysis. These parameters include high SDI’s, high levels of BAC and higher silica, iron levels, which were reported as satisfactory or nonexistent in the original analysis. As a result the third stage cannot be operated at the present time due to membrane fouling. So currently total systems concentrate water has increased from 22 gallons to 44 gallons, thereby decreasing the total recovery from 97.3% to 94%. Recovery is still very impressive compared to the industry standard maximum of 85%. The feed water quality issues are currently being addressed and once resolved, the third train will be reinstated.
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