Sound water treatment delivers environmental and economic benefits

A two-year collaboration between Ashland Hercules Water Technologies (AHWT; Wilmington, Del.), a commercial unit of Ashland Inc. (Covington, Ky.; www.ashland.com), and BASF Nederland B.V. (Nijehaske, the Netherlands) has demonstrated that a combination of ultrasonic microbial control and corrosion inhibitors not only enhances environmental performance, but also leads to a dramatic reduction in total operating costs for cooling water treatment. BASF opted to replace its complete cooling-water-treatment program — a conjugated phosphate treatment requiring pH adjustment through sulfuric acid dosing — with Ashland’s Enviroplus scale-and-corrosion inhibitor, in conjunction with an Ashland Sonoxide ultrasonic water-treatment system.

Enviroplus uses natural, biodegradeable and renewable ingredients (BCA-polymers and low phosphorous PSA phosphonate), and eliminates the need for sulfuric acid. The patented Sonoxide technology works by passing water through an ultrasonic chamber where bacteria cells are exposed to a combination of low-power, high-frequency ultrasound and micro-bubble aeration. This reduces the overall bacteria levels and eliminates biofilm formation within the entire cooling water system, says Olaf Pohlmann, AHWT’s Sonoxide commercial leader EMEA.

After two years of operation, not only was microbial control demonstrated, corrosion rates (measured on steel corrosion coupons) were shown to be reduced from 0.3–0.4 mil/yr to 0.23 mil/yr. Compareing with BASF’s previous water treatment costs to those associated with the Sonoxide system, engineers found that operating costs were reduced by 80%, chemical use was reduced by 90% and feed water savings of 20% were achieved. Results also show a preliminary savings of €20,000/yr from feed water and chemical use reductions, says Pohlmann.