The ion exchange process contains a polymeric resin with a chemical affinity for either cations or anions. The resin is not soluble in water and contains ion-active functional groups and swells by absorbing water into its matrix. Because of the functional groups of the ion exchange resins, the cation exchange resin is assumed to be in the H+ form and the anion exchange resin is in the OH- form. If a process solution contains positively charged cations (Mn+) and negatively charged anions (An-) and is exposed to ion exchange resins, the cation exchange resin will bind the Mn+ ion and release the H+ ion while the anion exchange resin will bind the An- ion and release the OH- ion. The ion exchange process requires an acid or base regeneration cycle.

The resins are normally contained in columns. The column consists of a resin bed with inlet and outlet screens, and service and regeneration flow distributors. Piping and valves are required to direct flow and instrumentation is required to control regeneration timing. Solutions are passed through the columns and the exchange occurs.

Waste acid streams are classified as hazardous waste. They may be treated through an acid neutralization process or filtration before disposal. The adsorption technology is an emerging alternative technology that is being considered for deployment by the Navy.

On behalf of the Navy, demonstration tests were conducted using a 1-inch diameter by 12-inch length, packed ion exchange resin column. A set of 10 experimental runs was made using concentrated sulfuric, hydrochloric, nitric, hydrofluoric, and phosphoric acids in combination with a variety of metals including iron, nickel, chromium, zinc, and aluminum. The tests represented typical conditions from anodizing, activation, cleaning, pickling, and stripping procedures. Acid recovery averaged over 80 percent for all acids that were tested. The process achieved recovery efficiencies in excess of 95 percent for acids of greatest interest such as hydrochloric, nitric, and sulfuric acids. Metal concentration appeared to have a negligible effect on acid recovery efficiency.

The use of an adsorption treatment system can help facilities meet pretreatment standards for discharges of wastewater to a publicly owned treatment plant (40 CFR 403) or meet effluent limits of a NPDES permit (40 CFR 122). In addition, this treatment process may help facilities meet the requirements of waste reduction under RCRA, 40 CFR 262, Appendix.

The Compliance Benefits listed here are only meant to be used as a general guideline and are not meant to be strictly interpreted. Actual Compliance Benefits will vary depending on the factors involved, e.g., the amount of workload involved.

Consult your local industrial health specialist, your local health and safety personnel, and the appropriate MSDS prior to implementing any of these technologies.

• Offers tremendous operational cost savings over current landfill disposal operations.
• Reduces hazardous waste generation.
• Produces more consistent, quality products.

  
  

Operational Cost Category	Dollars per Year
	Disposal	Adsorption
Material:	$4,200	$1,004
Labor & Clean-up:	$0	$31,600
Laboratory:	$0	$5,000
Utilities:	$0	$145
Secondary Treatment (@$53/1,000 gal):	$0	$12
Disposal (@$0.81/lb):	$56,700	$0
Regulatory Compliance:	$31,600	$700
Total Operational Costs:	$92,500	$38,461
Net Annual Savings:		$54,039

A summary of the financial implications for using an adsorption unit in shop activities, such as annual operating cost benefit and capital investment required, is shown in Table 2. The 15-year NPV and IRR, as well as the payback period are also listed in Table 2.

Table 2: Financial Implications of Using Adsorption vs. Conventional Disposal Practices

Category	95% Recovery Efficiencies	60% Recovery Efficiencies
Investment Required	$29,153b	$29,153b
Discounted Payback Period (year) a	0.6	0.6
NPV a	$425,177	$411.854
IRR a	182%	176%

a	This value was calculated with Pollution Prevention Financial Analysis and Cost Evaluation System (P2/FINANCE). This software is proprietary and copyrighted by Tellus Institute of Boston, Massachusetts. A 15-year analysis and 8% discount rate were assumed.
b	This number is based on the cost of the equipment, installation, and other contributing one-time fees related to the process.

Eco-Tec, Inc.
1145 Squires Beach Road
Pickering, Ontario, Canada
POC: Mr. Paul Pajunen
Phone: 905-427-0077

This vendor may not be the only supplier of this technology and there may be other suppliers of this type of equipment.