WE Credit 4.1 – Chemical Management
Prior to 2003 Johnson & Johnson Headquarters employed a conventional chemical system for cooling tower water treatment that consisted of on-site chemical drums, chemical pumps and a bromine feeder. The liquid chemical was stored in chemical drums and dispensed from the basement chiller room. Bromine was also stored in this location and dispensed by the maintenance staff. There was no side-stream filtration on the cooling tower loop.
Initiatives and Implementation
In February 2003 an ELECTROchem Water Treatment System was installed in the headquarters facility.
This system consisted of:
• ELECTROchem’s electrostatic probes on the inlets to the condenser heat exchanger on each chiller (3). The electrostatic probes replaced all chemicals that were being used for scale control (dispersants).
• A skid-mounted water treatment system in the Penthouse adjacent to the cooling towers (locked mechanical room). The water treatment skid is comprised of a side-stream filter with conductivity controller, corrosion coupon rack, a copper/silver electrode for bio control with back-up bromine feeder, and flow totalizers for filter, bleed and make-up. This system also incorporates a solid green chemical (organophosphonate) dispenser for corrosion control. The organophosphonate is a 12-pound jug of chemical that is replaced as needed by ELECTROchem as part of their annual service agreement (no chemicals stored on site).
Johnson & Johnson Headquarters installed a mechanical flow meter on the make-up to the cooling towers prior to the installation of the ELECTROchem water treatment system to validate monthly water savings over the prior year’s use (2002) (see attached savings reports). Since installation of the ELECTROchem system average monthly water use has been 25% less than that used in the base year, representing over 100,000 gallons saved each month, even though the conductivity setpoint was increased.
The ELECTROchem water treatment system eliminated 95% of all chemicals used and 100% of all chemicals stored on site.
Monthly biological bacterial counts have consistently been below industry standards (less than 1000ppm), and Legionella testing has been performed each summer with no traceable Legionella detected.
Corrosion rates have been under 1.5mils per year on mild steel and 0.14mils on copper.
The ELECTROchem side-stream filter does not use a media for filtration so there is no backwash required (considerable water waste). The particle precipitator puts equal amounts of positive and negative charges on suspended solids and drops them out in a cyclone separator. When the conductivity setpoint is activated the system purges itself.
ELECTROchem’s system will remove particles down to one micron. The electrostatic probes are designed to impart a negative charge on dissolved particles keeping them in suspension until they are bled out. The entire system is monitored through ELECTROchem’s onboard processor, which can be accessed locally through the chiller control room or remotely through a modem. The operators can monitor conductivity, filter flow, make-up flow and bleed flow. All flow meters are also totalizers, which provide an accurate reading of use each day.
The Johnson & Johnson Headquarters staff has been trained on the functions of the ELECTROchem system but does not get involved with the overall maintenance of the system, which is covered by ELECTROchem through their service agreement. The staff does clean the tower each spring and the system is laid up in late November (towers drained) each year. The staff also records monthly water readings for both bleed and make-up use, and these numbers are used in water the monthly savings calculations.
In 2005 three new high-efficient chillers were installed to replace the original building construction chillers. These chillers have enhanced tube exchangers and a high efficiency kw-to-tonnage ratio (three 500-ton Carrier chillers). At the same time the cooling towers were rebuilt with new distribution pans and fill, as well as an overall upgrade. Year-round cooling tower use was reduced to a seasonal April-November use. This also significantly decreased water use.
• 25% reduction in cooling tower water use
• 95% reduction in chemical use
• Scale-free heat exchangers
• High energy efficiency (no fouling)
• No chemicals stored on site
• 95% reduction in suspended solids
• Bio counts under 103 (below industry standards)
• Legionella testing results negative for Legionella
• Corrosion rates below industry standards
• Yearly cooling tower cleaning
• Monthly water chemistry analysis (cooling tower basin and make-up water)