Water Treatment

Davis & Shirtliff undertook a project to supply a Reverse Osmosis (RO) plant

D&S undertook a project to supply a Reverse Osmosis (RO) plant i.e. DRO8/4 for use in supply treated water to the UDV/EABL spirit plant at an average rate of 15000 litres per hour. The recovery of the plant was designed at 70% recovery. (Permeate i.e. treated water to the feed water ratio).

Water to the Dayliff RO equipment is supplied pre-treated using a Ultrafiltration plant with a Silt Density Index (SDI) of not more than 2.5 i.e. SDI <2.5. The plant was designed to high specifications according to the Diageo Engineering Standards which are heavily based on the European Standards.

The scope of D&S include the supply of the low pressures booster pump, dosing systems (pH, SMBS and Antiscalant dosing), Micron pre-filter (5 micron), DRO8/4 water treatment equipment, 5000 L Clean water buffer tank, Clean water transfer pump, the CIP chemical tank and CIP pump.

System Process Flow

The Grundfos CR 20-3 low pressure pump supply’s about 20m3/hr at the feed pipe to the pre-filter that filters raw water to about 5 micron. Testing of potential Hydrogen (pH), Total dissolved solids (TDS) and the Oxidation Reduction Potential (ORP) are done before the raw water is pushed in the RO membranes using the Dayliff DIN 32-8 High Pressure pump for comparison and monitoring on permeate side after treatment.

Feed water is also dosed with an antiscalant to inhibit scaling on of the water RO membranes which are prone to scaling thereby improving the water treatment plant performance. The RO membranes are not friendly to any chlorine present in the raw water and hence sodium metabisulphite (SMBS) is dosed at the feed line to remove any chlorine that may damage the RO membranes. Pressure switches in the feed line ensures that the raw water to the High Pressure Pump achieves the design pressures before the starting of the High Pressure Pump. Treated water is then transferred to the 5000 litre clean water buffer tank.

Part of the concentrate waste water from the RO membrane is recycled back to the feed line to improve the recovery of the plant to the desired design recovery not less than 70% (permeate water to the feed water ratio). The rest of the concentrate is then drained as waste. An optional pH dosing point on the permeate line is also provided to ensure that permeate water pH is adjusted to the recommended values if need be.

A permeate auto flush line is also provided from the clean water buffer tank to the feed line for flushing out waste within the RO membrane frequently as designed/desired to avoid clogging of the RO membrane and improve its life span. The Pedrollo Al-red pump is used to facilitate the auto flushing process with the help of pneumatic valves for automation of the process.

A Grundfos CR 32-3 pump is used as the transfer pump of the clean water from the buffer tank to the 60m3 clean water storage tank, within the UDV facility for use in spirit/alcohol production. The transfer pump is controlled using the level sensors available on the buffer tank depending on water level within the tank. A flow meter, pressure gauge and sample port are provided on clean water side for monitoring and testing. A bypass valve is also included to ensure any liquid waste during cleaning of the tank and be diverted to the drain.

Cleaning in Place system is also included in the design to ensure that CIP process as desired can be performed on the DRO8/4 plant to improve the performance of the Dayliff water treatment plant and ensure longevity. A Grundfos CM 15-2A pump is used to facilitate the CIP process using all the appropriate Chemicals. A CIP chemical tank is used to hold the chemicals used for the CIP process while a flexible hose used to hook up the CIP pump to the CIP feed point on the inlet side of the RO membranes.

System Control

The Dayliff water treatment plant is fully fitted with high specification controls and instrumentation that ensure intelligent and automatic operation of the DRO8/4 plant for improved performance and operation.

The control panel is fitted with a user friendly touch screen Human Machine Interface (HMI) that displays the operation process of the Dayliff Water treatment equipment together with notable design parameters trends of the raw water quality such as the TDS and the RO inlet and Concentrate pressure trends and graphs them overtime while storing history of these parameters to inform on the health of the plant.

A PLC unit is programmed to carry out all the Dayliff Water treatment plant operation while monitoring key design parameters and may shut down the plant or run a specific operation as desired/designed. For instance, if the antiscalant chemical tank is empty the control panel will shut down the plant to avoid scaling of the RO membranes until the antiscalant chemical tank is refilled. The Dayliff Control Panel will also automatically runs a permeate auto flush after a planned shutdown to flush any debris that might have been collected anywhere on the system to waste drain.

The control panel has various User Management Rights that allow the users of the DRO8/4 plant to create usernames and passwords with different rights and abilities. The Admin Group usernames have all rights available for the control and operation of the Dayliff Water treatment plant and is suitable for the Areas Owners/Engineers within the UDV facility while the Supervisor Group usernames have the right to operate the plant and monitor various parameter logs of the plant and is suitable for Supervisors within the UDV facility. The User Group usernames only provides right to operate the plant and are suitable for the UDV operators of the plant without interfering with any other aspects of the DRO8/4 plant operation.

The control panel houses various safety controls such as fuses, surge protector and safety relay for protecting various high capital equipment on the Dayliff water treatment plant from burning in the event of any electrical faults. All the control and instrumentation items are properly spaced and located within the control panel for efficient thermal management within the control panel.

The Dayliff DRO8/4 control panels is the master control panel and controls the operation of both the Dayliff water treatment plant and an existing 10m3/hr General Electric Reverse Osmosis plant (Ge RO). The Dayliff control panel receives operation signals from the Ge RO and the buffer tank water levels and controls the operation of the transfer pump whilst managing the operation of these two plants based on water demand for UDV spirit production from the 60m3 water storage tank. The Dayliff Control panels also manages the operation of both RO plants if one of the plants is under maintenance or perhaps not operational.

One of the most notable features of the Dayliff control panel is that it houses a Variable Speed Drives that optimizes the operation of the High Pressure Pump i.e. Dayliff DIN 32-3 pump, which is a high energy consumer to the desired operation Duty Point of the High Pressure Pump thereby reducing the overall short and long term energy costs of the Dayliff Water treatment Plant.

The Dayliff Control Panel also provides various alarms with user messages of problems encountered that occur during the operation of the Dayliff Water Treatment plant providing preliminary basis for the operator of the RO to start trouble shooting. This helps improve the user friendliness of the equipment during operation and maintenance.