City of Midlothian Raw Water Pump Station Expansion

Shrader Engineering Inc. (SEI) provided electrical, instrumentation and security systems engineering services as a sub-consultant to Schrickel, Rollins & Associates for new Pump Station 2 and Water Plant 2 to furnish raw water as part of Phase I & 2 designs for a new ultimate 36mgd water purification facility for the City of Midlothian Public Works.

SEI scope included electrical power, controls, instrumentation, SCADA, and video surveillance design for the pump station and water plant, plus MEP design for building HVAC systems. Electrical service was derived from local power company 12kv transformers for powering the series of 350hp VFD driven high service pumps. SEI performed power analysis using EasyPower software to determine fault and power conditions for the power network based on fault current data from the Power Provider. Initial electrical power to pump station and water plant was in excess of 6.6 megawatts with capacity for future expansion.

All controls are solid state with backup redundant Programmable Logic Controllers. The SCADA system design allows control of the overall water system from two water plants and the raw water pump station, linked via a new 20,000 ft. underground fiber cable to Water Plant 1 and via a new on-site Ethernet fiber link to Water Plant 2 main control room. The SCADA link was later expanded to include monitor and control of existing remote pump station 1 from any of the water facility sites.

SEI designed a SCADA link from Pump Station 2 to monitor and control new Water Plant 2 process equipment and instrumentation including main switchgear, motor control centers, VFD starters, membrane filter racks, feed pump controllers, UV disinfection reactors, chlorine dioxide and peroxide analyzers and metering pumps, VFD flocculator drive motors, recycle pumps and sludge collector equipment. Chemical tank-farm level signals are transmitted to SCADA for measuring daily chemical usage to automatically trigger order requests. Pump station flow is paced by nearby Water Plant 2 and remote Water Plant 1 process demand via the SCADA link. Over a period of 10 years, SEI has designed SCADA and controls at all City of Midlothian water facilities to form a fully integrated and automatically controlled water production system for the City. Over this period of time, SEI has performed electrical design and PLC programming services for the City by direct contract.

In addition, Shrader Engineering provided electrical design, instrumentation/controls design, SCADA programming, security design, and construction phase services for expansion of the existing raw water pump station 1 by addition of 700 horsepower, 4160 volt, VFD controlled raw water pumps.