Case Study

Manufacturer Implements Recycling Projects, Wins Industrial Achievement Award

Projects to minimize water use, maximize water reuse, and convert scrap lead paste to recyclable filter cake helped Hawker Energy Products Inc. (HEPI; Warrensburg, MO.) win one of two 1998 Industrial Water Quality Achievement Awards from the Water Environment Federation (WEF; Alexandria, VA).

The improvements also have helped the company more than double manufacturing capacity and generate more than $50 000 per year from selling scrap lead to a secondary smelter, says John Barricklow, HEPI's environmental manager.

The 30 000-m2 (320 000-ft2) plant, which is part of the United Kingdom-based Hawker Group (the world's largest industrial battery distributor), produces sealed lead batteries.



HEPI received International Organization for Standardization (ISO) 9001 certification in 1995 for its product design, manufacturing, assembly, and customer service functions and was among the first U.S. battery companies recommended for ISO 14001 certification.

Catalysts for Change

In 1994, HEPI began a project that would nearly double the size of its existing manufacturing and warehousing facilities. In 1995, the company decided to modify and expand its 95-L/min (25-gal/inin) wastewater treatment facility, because its loading periodically approached permit limits and operators often had to work overtime to meet treatment requirements; an effluent reuse system installed in 1988 was abandoned shortly after it went on-line because sodium hydroxide, sulfuric acid, polymers, and flocculants used in the wastewater treatment process hardened water so much that it was unsuitable for reuse; and metal-grate-covered concrete trenches used to collect lead-paste-laden wastewater from equipment and floor cleaning were ineffective. Each month, operators had to shovel out lead paste that had collected in the trenched and ship it to a certified storage and disposal facility, Barricklow says. In 1994, the year before the wastewater treatment plant was upgraded, almost 227 000 kg (500 000 lb) of lead paste was shipped offsite.

Solutions

The company conducted a two phase project to solve the problems. (Water reduction projects were carried out simultaneously during both phases.) The first part of the project, which took place during a 3week planned facility shutdown, involved increasing tank capacity to keep undesirable chemicals out of potential reuse waters, replacing collection-sump mixers, and installing an additional filter press to remove particulate lead and other solids before pumping water to the reuse or lead-removal system.

"We had attempted water reuse before," Barricklow says, "but because of chemistries in the wastewater, we experienced salt buildup that was detrimental to our product. We made reuse feasible by rerouting side streams to eliminate the problem. We recycle most of our water now and currently are working on a project to collect condensate from air conditioners and use it to freshen cooling towers.

"The "core" of the plant's wastewater treatment system is the UniPure co-precipitation system from UniPure Environmental (Fullerton, Calif.). The system uses ferrous chloride to entrain lead, Barricklow says. "When the pH is adjusted, the iron precipitates out and takes the lead with it," he explains.

The first phase of improvements also included installing an automated collection system for lead-paste washdown wastewater. Sewer and water pressure lines and automatic valves were placed inside the concrete collection trenches to allow large amounts of reuse water to be pumped in to carry paste to the paste sump. The contents of the paste sump now are pumped through a plate filter press, and filtered water is pumped back to the reuse loop. Filter cake is approximately 85% solids, which exempts it from hazardous waste regulations as long as it is reclaimed.

The second phase of improvements involved installing a wastewater collection system in the company's new plant (where flat-plate batteries are manufactured). The system collects, neutralizes, and stores acidic wastewater; collects, filters and distributes lead-paste wastewater; collects and stores soapy water; and transfers wastewater to the UniPure Lead Removal System in plant No. 1 (where cylindrical batteries are manufactured).

Plant improvements have enhanced performance of the lead removal system because, by the time wastewater reaches it, lead content is in the parts per million range, Barricklow says. Lead content in effluent now is less than 10ppb, which is "less than in the city water," he adds. Because effluent is batch-discharged, the facility can test lead content before discharging it. "If we detect a problem, we just send all the water in the tank back through the system," he says. "It is virtually impossible for us to have [a lead] violation."

-Kellye Kratch, IW