Thomas & Hutton provided engineering design services for Mount Pleasant Waterworks’ Reverse Osmosis Water Treatment Plant No. 4. Thomas & Hutton’s responsibilities included building and process design, permitting, bidding, construction, and start up services of a 1.4 mgd (expandable to 2.1 mgd) reverse osmosis water treatment plant and 4,100-square foot building. Raw water comes from a cretaceous aquifer deep well with a feedwater TDS of 1,600 mg/L. Two reverse osmosis trains were designed with a 10:5-7 element array using Hydraulic ESPA 2 membranes.

The water treatment plant boasts the following features:

• Antiscalant pre-treatment system and calcium chloride post-treatment system
• Calcium chloride bulk storage tank
• Chloramines disinfection system
• Instrumentation and controls with fully integrated programmable logic controller
• 600kW auxiliary generator
• Incorporated into existing plant site to use ground storage tank and HSPs
• Harn reverse osmosis systems was the ROEM