Weyerhaeuser Company
Summary of NESHAP Source Category
A Summary of NESHAP for Source
Category: Pulp and Paper Production
Federal Register: March 8, 1996 (Vol 61
No. 47)
pp. 0383-9399
This summary contains a brief overview of the proposed rule excluding, the subcategories of sulfite, soda, and semi-chemical mills, and section X, which covers standards for Nonchemical Pulp Mills (MACT III). The section headings in the summary correspond to those in the Federal Register notice.
SUMMARY:
- Sets forth the most significant changes EPA is considering (not inclusive of all changes)
- Announces proposed additional sources not covered by 1993 proposed standards
- Mechanical mills
- secondary fiber mills
- non-wood fiber mills
- paper machines- Proposed NESHAP for chemical recovery area combustion sources at mills will follow in separate action later this year
BACKGROUND
HISTORY CAA requires EPA to develop NESHAP for pulp and paper source by Nov '97 Goal of NESHAP: Require the implementation of MACT to reduce emissions and, therefore, reduce the public health hazard of pollutants emitted from stationary sources. EPA OW plans to issue a similar FR notice for the effluent guidelines portion of the cluster rule in about four weeks. MACT I: address air emission points in the pulping and bleaching precesses and in the associated process, wastewater collection and treatment systems
- standards being developed in phases
MACT II: combustion sources
- standards will be proposed later this year
MACT III: apply to mechanical pulping; pulping of secondary fibers by nonchemical means; non-wood pulping; and paper machine additives.
- standards discussed in section X
Data shows that pulp and paper emit high levels of HAP's that would be controlled by the proposed standards
- some pollutants are carcinogenic; all can cause toxic health effects following exposure, including nausea, headaches, respiratory distress, and possible reproductive effects
- most are classified as VOC's Proposed rules will reduce VOC emissions as well as TRS compounds (odor producers) SUMMARY OF ACTION (focusing on kraft mills and bleaching process) Changes of proposed rule include:
- revisions to emission factors
- broadening of source definition
- development of subcategories for pulping
- revisions to MACT requirements and how they are applied
- revisions to MACT compliance schedule for kraft mill emission points New approach for emission factor development: involves developing emission factors for functional mill systems as opposed to individual emissions points Plans to expand single source definition to include paper machines and the causticizing are due to relationship with pulping and bleaching areas EPA plans to subcategorize the pulping and associated wastewater components to develop different MACT requirements
- This is necessary to reflect important difference between the pulping process emissions, emission controls and control cost
- The subcategories are: kraft, sulfite, soda, and semi-chemical For existing source MACT applicable to the pulping component at kraft mills, EPA is considering specifically defining the following systems as requiring enclosure and venting to a control device
- the low volume-high concentration vent system (LVHC)
- weak black liquor storage tanks
- pre-washer knotting and screening system
- brownstock washing system
- oxygen delignification (OD) system EPA intends to define new and existing source MACT for kraft mill wastewater to be collected and treatment of certain named puling condensate streams instead of all pulping wastewater above 550 parts per million by weight (ppmw) EPA is considering changing the proposed treatment requirements for steam strippers at kraft mills to allow compliance with one of the following:
- removal of 92% of HAP or methanol content
- removal of 9.2 pounds of methanol per air-dried ton of pulp (lb/ADTP)
- treat to a steam stripper outlet HAP concentration below 330 ppmw measured as methanol Unbleached kraft mills have separate requirements, but are not listed in this summary Mills still have option of achieving these removals with an alternative control device, recycling to a controlled system, or hardpiping these condensate streams directly to the biological wastewater treatment plant instead of steam stripping EPA is considering extending the compliance time for controlling brownstock waters and OD units for kraft pulping mills by 5 years (for a total of 8 years) EPA is considering additional standards for newly created sulfite, semi-chemical, and soda mill categories: these are not discussed in this summary. A new limit of 10 ppmv of chlorinated HAPs from the outlet of the scrubber is also now being considered, as opposed to the 99% removal limit in the proposed NESHAP Paper-grade bleaching processes would be required to control chloroform air emissions by complying with the BAT economically achievable (currently under development by OW) EPA is considering recommending to State permitting agencies that mills complying to cluster rule be granted the "pollution control project" (PCP) exclusion and be allowed to conduct minor NSR only.EMISSION FACTORS
New approach involves developing emission factors based on mill systems rather than on individual emission points- mills often utilize different configurations of equipment within a system, therefore, point by point comparisons are misleading
DEFINITION OF SOURCE- averaging pieces of equipment can provide an inaccurate estimate of total system
- mill system approach makes comparison between mills possible
- mill systems approach lessens the problems associated with the nomenclature assigned to each of the components EPA still wants to use single source definition, but considers the broad source def. the best interpretation for the pulp and paper industry
- due to the interrelated nature of equipment single source most appropriate
- broad source would alleviate concerns that a small change to an existing mill that creates a small increase in emissions would trigger new source requirements in NESHAP. Inclusion of paper machines and causticizing equipment
- emissions form these sources are also interrelated
EPA intends to include the processes for treatment of condensate streamsSUBCATEGORIZATION
- removes HAP's prior to recycling which reduces emissions from equipment
- a mill could take credit for emission reduction form these processes if it chose to implement the Clean Water Alternative Would establish four separate subcategories for the pulping processes at mills based on the type of pulping process (draft, sulfite, semi-chemical, and soda) used. A difference in the result of digestion methods cause the mills to produce different emissions that result in different degrees of control at baseline and different applicable control technologies.
- kraft: generates high quantities of TRS compounds
- sulfite: contain sulfur dioxide (SO<ICF>2)
- soda and semi-chemical: similar to be lower than kraft If two or more subcategories are located at the same mill site and share a piece of equipment, the piece with the more stringent MACT subcategory requirement would be consideredLEVEL OF STANDARDS
EPA does not currently consider subcategorizing among bleaching processes, but may distinguish between papergrade and dissolving grade bleaching processes for purposes of setting chloroform MACT requirements for bleach plants EPA is also considering naming specific vents and streams subject to the standard instead of determining affected emission points and wastewater streams based on broad groups of equipment with exclusions for small streams Requirements for control of emission form kraft pulping wastewater prior to treatment would still apply to condensate streams, however the treatment limits for them may be changed. EPA is considering adding some requirements for the control of chloroform emissions and additional ways to meet the treatment requirements of the closed vent systems from the chlorinated bleaching stages EPA is considering dropping the requirement for control of non-chlorinated HAP's in the bleaching area (i.e. methanol)KRAFT
EPA is tentatively intending to establish control applicability by specifically defining the equipment systems and associated wastewater streams subject to the MACT standard.
- EPA believes this changes will result in the same level of control at the MACT floor for both wastewater and process equipment, yet will reduce or eliminated the cost of testing that would have been required by 1993 proposal.
The following named pulping processes have new def. under consideration: (the definitions are not summarized)
- LVHC vent system
- brownstock washing
- OD system
- pre-washing screening system EPA is considering to distinguish between types (new or old) of weak black liquor storage tanks
- questions remain over what level of control represent the MACT floor for the different tanks
Concerns remain over control of pre-washer knotter and screening systems EPA is inclined to agree that naming of pulping wastewater and condensate streams better identifies the streams to be controlled at the MACT floor EPA now considers the subject wastewater streams to be foul condensates and in inclined to adapt the following definitions for equipment: (foul condensates, evaporator system, condensate segregation, segregated condensate stream) (see FR for def). New data indicates that the best performing steam strippers representing the floor level of control achieve a combination of the following (because methanol is a good indicator of total HAP removal for pulping processes and associated wastewater, any one of these parameters demonstrates that total HAP are being removed):
- high percent methanol removal
- high methanol mass removal
- low outlet methanol concentration EPA now considers that mass removal and outlet concentration are valid parameters to set control limits in addition to percent removal. The rule would allow mills to:
- Choose any wastewater treatment device as long as the device achieves one of the three parameters and as long as the wastewater is conveyed to the treatment device in an enclosed conveyance system or
- recycle the wastewater streams to a piece of equipment meeting the control requirements EPA currently intends to distinguish between bleached and unbleached mills for setting MACT level of control for pulping wastewater New industry data on steam stripping tech. indicates that the MACT floor level of control for puling wastewater at both bleached and unbleached kraft mills is treating the foul condensate wastewater streams to remove 92% of the HAP contents EPA is considering soluble BOD as a compliance parameter alternative for biological treatment compliance (see docket items).