Zero Waste Logo The Zero Wate Network the University of Texas at Arlington Center for Environmental Excellence Environmental Training Institute Logo  

Join Us on:

Social Network Nav Bar

Lean and P2 Workshops

Nov, 14-16, 2017,

Dec. 5-7, 2017




Environmental Management Systems Workshops

Lake Charles
Sep. 26-29, 2017

Dec. 12-15, 2017



Case Study Database

           Add Story    |    Search Case Studies    |   



Year Submitted: 2003

Process: Stack Gas Cleaning

Industry: Chemical Manufacturing

Wastes Reduced: Stack Emissions

Substance: SO3

Equipment: Scrubbers

Location: Houston, Harris County TX

No. of employees: 189

Contact: Gavin S. Floyd


The Rhone-Poulenc Houston plant produces various grades of Sulfuric Acid, some of which are saturated in sulfur trioxide (SO3) to the point that they fume continuously in atmospheric storage tanks. The plant had a vent scrubber on its storage tanks but the water (3 to 5 gpm) used to scrub the vent gases was very acidic and required 0.5 to 1.0 tons caustic per day to neutralize it before discharge into the plant treatment system.

P2 Application:

A new system was designed with waste minimization and cost reductions in mind. It utilizes surplus equipment from Rhone- Poulenc's Seattle, Washington plant that was shutdown in 1991. The Investment Recovery Department published a booklet of all equipment that was available. Houston plant personnel quickly acquired a Carpenter 20 tower, acid pumps and a small 1,200 gallon tank. These components evolved into a new scrubber system that utilizes circulating sulfuric acid as the scrubbing fluid. The new system completely eliminates the acidic water as well as neutralization costs. Additionally, 0.5 to 1.0 tons sulfuric acid are produced daily.

Environmental Benefits:

The amount of sodium sulfate discharged to Buffalo Bayou was reduced by 400 tons per year.

Details of Reductions

Additional Information :

The annual savings of this project are $99,000 and the payback period is 1.6 years. The caustic cost was reduced by $82,000 per year and the recovered sulfuric acid is worth $17,000 per year. The project cost $160,000.

Source: TCEQ

SHEP Shield
Health and

ERP Shield

ESP Shield

EMP Shield

Attend a workshop and
earn credits toward a
Professional Certification



The Zero Waste Network is one of eight Pollution Prevention Resource Exchange P2RxCenters , serving as a national network of regional information centers: NEWMOA (Northeast), WRRC (Southeast), GLRPPR (Great Lakes), ZeroWasteNet (Southwest), P2RIC (Plains), Peaks to Prairies (Mountain), WSPPN (Pacific Southwest), PPRC (Northwest). We are a proud member of the National Pollution Prevention Roundtable.

National P2 Roundtable Logo