The New-Indy air monitors are stationary instruments that provide data that is averaged over 30-minute periods of time. The onsite instruments measure hydrogen sulfide (H2S) down to four-tenths parts per billion (0.4 ppb). The offsite instruments measure hydrogen sulfide (H2S) down to two-tenths parts per billion (0.20 ppb). The purpose of the stationary monitors is to provide quantitative information regarding H2S concentrations at New-Indy and in the community. The red line in the graphs is set at 70 ppb, which is the 14-day Minimum Risk Level (MRL) for H2S exposure developed by the Agency for Toxic Substances and Disease Registry (ATSDR). An MRL is defined as an estimate of daily exposure to a substance (H2S) that poses a minimal risk of adverse effects to humans over a specified duration of exposure (14 days).

No. The South Carolina Department of Health and Environmental Control (SC DHEC) routinely monitors public drinking water as well as the water quality of the rivers in South Carolina. The intake for drinking water systems supplying the neighborhoods in the area are UPSTREAM from the New-Indy discharge. The nearest downstream intake is 9 miles downriver. No issues related to New-Indy have been identified that are affecting drinking water quality. SC DHEC, in coordination with the Catawba Riverkeeper, conducted a special study on the river, looking at upstream and downstream locations relevant to New-Indy. The study found there were no significant impacts to the Catawba River from the New-Indy wastewater discharge. The report can be found at https://scdhec.gov/sites/default/files/media/document/CatawbaRiverStudy_Final.pdf.

The Community Engagement Group (CEG) provides a way for New-Indy and its neighbors to communicate directly, to form relationships with each other, and to work together to identify concerns and develop solutions. New-Indy Catawba created the CEG to improve dialogue with residents in the communities surrounding the facility and to build respect, trust and confidence with local citizens. We hope that this will help identify and resolve any concerns. New-Indy Catawba remains firmly committed to operating in a safe and sustainable manner, which will have a positive impact on the local community and South Carolina.

The stripper treats foul condensate (foul in this instance denoting “dirty” condensate discharge) generated during the manufacture of pulp to strip hydrogen sulfide (H2S) and other non-condensable gases (NCG’s) from such condensate. The stripped H2S and NCG’s are then burned in one of the combustion boilers at the mill. At present, the stripper is not sized to treat all foul condensate generated by the mill. New-Indy is investigating several modifications that it may make to the stripper and related equipment to increase the volume of foul condensate that the stripper can process.

The layer of fiber on the ASB was the result of initial startup operations following the conversion from bleached paper to unbleached containerboard. The fiber interfered with the proper operation of the ASB and made it difficult for mill personnel to conduct preventive maintenance and repairs. As a result, several aerators in the ASB became inoperable. The situation was exacerbated by the inclement weather in January and February which prevented timely access to the ASB for heavy equipment contractors to begin the solids removal process. Beginning on March 1, 2021, New-Indy began removing fiber from the surface of the ASB. This effort has continued using various methods, including using a barge to dredge and push fiber toward the edge of the ASB. Fiber that is removed is hauled to the No. 4 sludge pond where it is processed with other similar waste. These continuing remedial measures to remove fiber have allowed personnel to reach the aerators, conduct maintenance and repairs on those aerators and return them to service, which has improved performance of the ASB and reduced related air emissions and odors.

A stack test, also referred to in EPA regulations as a performance or source test, measures the amount of a specific regulated pollutant, pollutants, or surrogates being emitted from an air emissions source, such as a stack or vent. Testing is required by a facility’s Title V Air Permit on a periodic basis. Testing the air emissions from these devices (stacks/vents) requires highly sophisticated protocols and techniques to ensure that the air quality is accurately measured and characterized. All of the stack tests required by EPA and SC DHEC have been performed, and the sampling and testing results are being analyzed to ensure data quality. This data has been submitted to SC DHEC for review and evaluation. Once approved by SC DHEC, the data will be used to generate air dispersion models to evaluate any potential offsite impact from New-Indy’s emissions.

A large amount of data has been generated by the EPA monitors, which has been helpful in pin-pointing locations where H2S levels might be elevated. As such, SC DHEC has concurred in the placement of New-Indy monitors in the areas most likely to experience elevated levels of H2S and at locations where permission was granted to install a monitor.

The option to discharge the foul condensate to the wastewater treatment system instead of through the steam stripper is allowed under the federal air regulations (40 CFR Subpart S). SC DHEC approved the hard piping of the foul condensate in a revised construction permit issued on May 13, 2020. When the odor issue arose, New-Indy voluntarily decided (with SC DHEC approval) to restart the stripper on May 3, 2021.

The production of pulp and paper is a water intensive process. Converting wood into paper requires a combination of physical, chemical, and thermal steps that produce fiber stock, recoverable energy, and process water that contains impurities that must be removed before it can be discharged. Fully integrated pulp and paper mills, such as NICB, employ systems that treat as much wastewater each day as a medium-sized city of over 100,000 people.

The U.S. pulp and paper industry is a highly sustainable industry and has made great environmental strides over the past 20-30 years in terms of reduction in amount of water consumed per ton of paper produced, quantity of permitted components discharged, such as biochemical oxygen demand (BOD) and total suspended solids (TSS), and air emissions of hazardous air pollutants (HAPs) from wastewater collection and treatment systems. Most mills recycle significant quantities of process water, recover/refine chemicals from the wood (turpentine, soaps, and tall oil), and produce steam and electricity from such wood lignin burned in the mill’s recovery boilers.

The reality is that water can be recycled only to a certain point, after which it must be purged, collected, treated, and discharged to a receiving stream. No recovery or refining process is 100% efficient. There are practical limitations in recovering or removing all of byproducts and impurities that leave the mill, which necessitates the existence and operation of a wastewater treatment system that employs biological and physical treatment technologies.

Sludge is the term for the biological solids generated when microbes (bacteria) degrade organic matter. As the microbes convert the organic material (BOD) into carbon dioxide and energy, they reproduce, creating additional bacterial cells. When all, or most, of the BOD is converted, the bacteria run out of “food” and the solids settle to the bottom of the ASB or #1 Holding Pond creating a layer of solids referred to as sludge. It is important that these solid particles settle somewhere in the system to avoid being discharged.

The short answer is “maybe”. The limitations are the variability of the nutrient content in the sludge, permitting considerations, and the costs of handling, hauling, and application. NICB is continually exploring beneficial reuse opportunities for the various solid byproducts produced in their process.

The NICB wastewater is treated in a system referred to as an Aerated Stabilization Basin (ASB) and is the most common type of wastewater treatment system used by pulp and paper mills in the Southeastern United States. The term ASB generally is assigned to both the specific basin that contains the bulk of the aeration and the entire system including the settling and holding ponds. There are five steps involved in the NICB treatment process:

1. Collection and transfer of the wastewater from the many locations throughout the mill to the wastewater treatment system via a network of sumps, pumps, and lift stations.
2. Primary treatment – Settling of insoluble material in a primary clarifier, which removes fugitive solids such as wood fiber, boiler ash, lime mud, and general silt and sand.
3. Reduction of BOD and other specific compounds that can be detrimental to aquatic life in the Catawba River. This occurs primarily in the ASB. The soluble BOD is converted to additional bacteria (biomass) resulting in an effluent that contains an acceptable BOD concentration under the National Pollutant Discharge Elimination System (NPDES) permit and the newly formed biomass, which must be removed by settling before discharge.
4. Settling of solids created by the conversion of soluble organic matter (BOD) into additional bacteria (bugs) to avoid discharging solids to the river. This occurs in the #1 Holding Pond, which also serves as an equalization pond to hold water and discharge in a manner that ensures permit compliance and provides an additional layer of protection to the Catawba River.
5. Discharge to receiving stream is monitored for numerous parameters that are listed in the NICB’s NPDES permit.

BOD is the abbreviation for biochemical oxygen demand and is a measure of the biodegradable organic material that is in the wastewater. The bacteria in a wastewater treatment system function identically to the naturally occurring bacteria in a stream, lake, or river. The bacteria utilize available dissolved oxygen (DO) to metabolize organic matter to create additional bacteria and carbon dioxide. As related to humans, the way we measure the “strength” of our food is in calories, which is analogous to BOD for the bacteria. In both cases, the organic material is aerobically metabolized to produce energy, new cells, and carbon dioxide.

Removal of BOD prior to discharge is critical because a “receiving stream”, i.e., a river or lake, must maintain adequate dissolved oxygen (DO) levels to support desirable aquatic life, such as game fish like bream, crappie, bass, and trout. All streams have a natural ability to handle a certain amount of organic loading from agricultural, municipal, and industrial discharges. This is called the assimilative capacity of the stream. If the total amount of BOD or other contaminants does not exceed this capacity, the receiving stream can naturally metabolize the organic material, thus maintaining a healthy environment for the aquatic life. If the assimilative capacity is consistently or excessively exceeded, the bacteria in the stream will consume more oxygen than is naturally replenished resulting in stream oxygen concentrations dipping below necessary levels to sustain aquatic organisms such as fish.

No manufacturing facility, including NICB, has any incentive to create or release waste material that must be treated or hauled away for disposal. The components in a wastewater stream are comprised of impurities that adversely impact the quality of the paper produced and some desirable materials that the mill would prefer to capture in the process. Therefore, NICB has an incentive to minimize the loading to the ASB, which directly reduces the potential for odor formation.

When the bacteria utilize oxygen to degrade the BOD, the main byproduct is odorless carbon dioxide (CO₂). However, ASBs are large non-homogenous ponds with numerous competing biological reactions occurring simultaneously. One of those competing reactions is carried out by a group of bacteria known as sulfate reducers (SRBs), which also can degrade BOD. Instead of using oxygen, SRBs use sulfate (SO₄) as their “oxygen” source. The resulting byproduct is odorous H₂S instead of CO₂. Since sulfate is a very common, naturally occurring compound, H₂S formation can occur in virtually any wastewater treatment system, as well as lift stations, sewer lines, and agricultural ponds.

Formation of H₂S and other sulfides is inevitable and even desirable in an ASB, because it is the byproduct of anaerobic sludge digestion at the bottom of the basins. This reduces the volume of solids produced and is an essential component of the technology. The sulfides formed in this process are re-absorbed in the water layer of the ASB and do not leave in the air in measurable amounts. The problem occurs when the hydrogen sulfide formation rate exceeds the assimilative capacity of the water layer, resulting in H₂S emissions to the atmosphere. The situation is aggravated or complicated by the dynamic nature of the treatment system and weather conditions. Therefore, New-Indy has instituted a variety of proactive and reactive steps to minimize the formation and release of odorous compounds from its wastewater treatment system. Many of these items are listed and briefly discussed below.

Note: Hydrogen sulfide (H₂S) and its similarly odiferous cousins, such as methyl mercaptan and dimethyl sulfide, have many potential sources beyond ASBs and sewage treatment. In fact, mercaptans such as dimethyl sulfide are added to odorless natural gas for safety reasons. Hydrogen sulfide is commonly an issue for municipal wastewater collection system due to low flow, anaerobic conditions in collection systems and lift stations. Lastly, marsh gas, also known as swamp gas, is a mixture of methane, hydrogen sulfide, carbon dioxide, and trace phosphine produced naturally within some marshes, swamps, and bogs.

As discussed previously, minimizing mill losses and process upsets is the first place to start, and best management practices in pulp and paper mills generally include continually investigating and evaluating potential improvements from this perspective. This answer will focus on the wastewater treatment system, which is tasked with handling what leaves the mill and protecting the environment.

Optimizing the aerobic treatment component of the ASB is priority one. This includes:

• Maintaining sufficient aeration in the aerated portion of the ASB to ensure that undesirable H₂S formation in the ASB is minimized¹,
• Installing a unique biosensor probe technology to provide real-time data regarding the health and performance of the ASB¹,
• Strategically dredging solids¹ to maintain adequate hydraulic retention time for treatment and prevent stagnant areas that can produce H₂S, and
• Evaluating supplemental nutrient and/or bacteria addition² to further optimize BOD treatment and reduce the potential for H₂S formation in the #1 Holding Pond.

In addition to the aeration basin efforts above, the mill is taking or evaluating steps to eliminate H₂S emissions from the mill site. These include:

• Installation of additional aerators in the #1 Holding Pond to reduce stagnant locations and maintain an aerobic environment prior to discharge²,
• Using chemical additives (calcium nitrate, hydrogen peroxide, and ferric sulfate) individually or in combination to prevent/eliminate H₂S in the #1 Holding Pond¹, and
• Evaluating the applicability of in-pond monitors to better apply the above-mentioned chemical to prevent and/or remediate H₂S formation.³

¹ Currently in use
² Evaluation or installation planned
³ Under consideration