Wood preservation facilities, pentachlorophenol pressure: chapter E-9

9. Waste, Process Emissions and Disposal

For general information on process emissions and disposal, consult Section 9 of Part I, Chapter A - General Recommendations for All Wood Preservatives.

9.1 Control, Treatment and Disposal

The PCP oil-borne pressure treatment process generates liquid and solid wastes and emissions to air. Numerous approaches are used or can be used by the industry to control, treat and/or dispose of the process wastes and emissions. Potential sources of chemical releases from PCP pressure treatment facilities are described in Section 5.2 and in Figure 1. Table 23 identifies the main categories of process wastes or emissions that can be generated at PCPP facilities, and summarizes recommended control, treatment and/or disposal methods.

The processes used for waste disposal fall under provincial jurisdiction and may vary from province to province.

Federal and provincial regimes address hazardous waste and hazardous recyclable material in different manners. Provincial requirements may also differ from province to province. Consult your provincial authority for more information.

Control Requirements

Control specifications will depend on factors such as the volume and frequency of the discharge, and the sensitivity of the receiving environment. The discharge of chlorophenol-contaminated effluent into waters inhabited by fish is subject to the federal Fisheries Act. Refer to Table 3 for CCME water quality guidelines.

9.2 Waste Liquids Containing PCP

Liquid Process Wastes

Leaks and drips of oil solutions are contained and reused in the treatment process. Liquids such as condensates, washwaters and infiltrating waters, which cannot be reused, should be treated to remove oil and PCP prior to discharge (32, 23, 24). The treatment techniques include one or a combination of the following:

• gravity separation
• oil/water API separation, plate separation
• activated sludge treatment
• activated carbon treatment
• physical-chemical treatment (i.e. flocculation)
• evaporation/condensation

A regulatory discharge permit must be obtained for disposal of the treated aqueous wastes.

Contaminated Storm Runoff

Because PCP wood preservation facility sites are generally large, considerable volumes of storm runoff waters originate from these sites. Every precaution should be taken to avoid contamination of storm runoff water. See Section 7 for more details on design and equipment recommendations.

If contamination occurs, refer to Section 12 - Environmental Emergency Notification and Contingency Planning for more direction.

9.3 Solids with Potentially High PCP Concentrations

For the purposes of this document, solids with potentially high levels of PCP are defined as:

• sludges from sumps, concentrate and work solution tanks, and pressure cylinders
• sludges from wastewater treatment processes (e.g. flocculated materials)
• unwashed containers or wrappings for PCP blocks
• filters from cleaning vacuum

Guidelines for the Disposal of Solid Wastes

While awaiting disposal, the contaminated solids should be in leakproof containers in a specially designed area that is curbed with a paved or concrete sealed surface. The area should be roofed to protect the wastes from precipitation. Any seepage or leachate generated at the site should be contained. Refer to Chapter A, Section 9, Table 23 - Recommended Practices for Handling Liquid & Solid Wastes and Sludge for complete details.

The most feasible disposal option for chlorophenol wastes appears to be high-temperature thermal destruction by an approved facility. Refer to your local and provincial authorities for the best potential disposal options.

9.4 Disposal of Miscellaneous Solid Wastes

Refer to Chapter A, Section 9.4 - Miscellaneous Solid Wastes for complete details.

• Make the empty container unsuitable for further use
• Do not use PCP-treated wood as a compost or mulch.
• Incineration of PCP-contaminated materials is not permitted except in facilities authorized for disposal of such products because of the formation of toxic combustion by-products

9.5 Air Emissions

Air emissions at oil-borne PCP pressure treatment facilities are generally localized; effects, if any, would be restricted to workers at the facilities. Such emissions may include the following:

• dust and vapours from manual unwrapping of PCP blocks
• vapours from tank vents
• vapours from opening of retort cylinder doors
• vapours from freshly treated charges
• vapours from vacuum system outlets