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Water Quality Compliance Inspection Report

Industrial Section

Facility Name & Address: WestRock, LLC 801 Portland Avenue Tacoma, Washington 98421

NPDES Permit Number: WA0000850

Date of Inspection: February 21, 2019

Ecology Representatives: Emily Toffol, Shingo Yamazaki, Lindsey Hall

WestRock Representative: Karl Schumacher

Report by: Emily Toffol Report Date: March 11, 2019

Shingo Yamazaki, Lindsey Hall and I arrived at WestRock, LLC’s Tacoma Mill (WestRock) on February 21, 2019 for a Class I (non-sampling) water inspection. We were accompanied on the inspection by Karl Schumacher, WestRock Environmental Manager. The tour of the facility included observation of the salt water cooling water intake structure, primary clarifier, UNOX reactors, secondary clarifiers, effluent piping, and laboratory. Process data for each treatment unit was also collected. Operations were normal at the time of the inspection. The facility appeared to be operating in accordance with their NPDES permit. No enforcement action is necessary based on this inspection. Suggested improvements are included in the Conclusion Section of the report.

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FACILITY DESCRIPTION The WestRock facility is located in Tacoma, Washington adjacent to the mouth of the Puyallup River on the inner Commencement Bay. The mill is an integrated pulp and paper facility equipped with conventional Kraft pulping and chemical recovery systems. Process units include pulp digesters, pulp washers, a recovery boiler, two lime kilns, two power boilers, a three stage high chlorine dioxide substitution bleach plant, and paper machines. The mill produces a mix of bleached and unbleached pulp and paper products from chips and recycled old corrugated cardboard (OCC). The wastewater treatment facility has been issued NPDES permit No. WA0000850 for the discharge of treated wastewater and stormwater into the Inner Commencement Bay. The permit was effective as of October 1, 2014 and expires on April 30, 2019. A complete permit renewal application has been received and the permit will be administratively extended until a renewal permit is issued.

PROCESS WASTEWATER TREAMENT SYSTEM DESCRIPTION The mill treatment system includes a primary clarifier, a pure oxygen activated sludge (UNOX) system, and two secondary clarifiers. Stormwater and wastewater produced from various process units is routed to the primary clarifier, which is used to separate solids from the wastewater through settling. The UNOX system further treats the wastewater through a biological process with activated sludge. The final step is separation of the remaining solids, including solids generated by the biological process, through settling in the secondary clarifiers.

SITE INSPECTION This inspection was an unannounced site visit to evaluate general compliance with the NPDES permit. The tour of the facility included observation of the salt water cooling water intake structure, primary clarifier, UNOX reactors, secondary clarifiers, effluent piping, and the laboratory. Process data for each treatment unit was also collected. Below are my observations from the inspection. Suggested improvements are included in the Conclusion Section of the report.

Salt Water Cooling Water Intake Structure WestRock uses salt water for contact cooling water in their UNOX reactors, and for non-contact cooling water in heat exchangers. WestRock operates a separate suction line and pump for each type of cooling water. The cooling water intake structure sits on a barge located on the mill property. The submerged intake piping is covered by a coarse outer screen. The end of each intake pipe is covered by a cylindrical screen made of finer mesh (“inner screen”). Roughly six inches of the outer screen were visible above the water (Figure 1). Some mollusks and vegetative growth were attached to the outer screen under the water’s surface. Karl Schumacher said that the inner screen is cleaned when low intake flows indicate blockage, typically one to two times per year.

Primary Clarifier I observed a small amount of sheen on the surface of the primary clarifier (Figure 2). A small amount of debris was present in the weir with <5% blockage (Figure 3). WestRock’s Treatment System Operating Plan (TSOP) states that weirs should be cleaned when blockage reaches 25%.

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The effluent water was tinged brown but appeared to have low turbidity. At the time of our inspection, the effluent of the primary clarifier had a pH of 9.5, within the operating target of 5.5-9.7 stated in WestRock’s TSOP dated 10/20/2014. The east drive motor of the primary clarifier rake was running at 3.9 amps (A). The west drive motor of the primary clarifier rake was at 4.3 A. Page 4-4 of the TSOP states “If the amp differential between the drives is greater than 0.2 amps, there is a problem that warrants investigation”.

UNOX Per WestRock’s TSOP, mixed liquor suspended solids (MLSS) are sampled twice per 12 hour shift. This sample is taken from the third stage of the East and West UNOX reactors. The samples are tested for initial dissolved oxygen (DO) content. Karl Schumacher provided a print out of wastewater process trends dated 2/21/19 9:42 AM. The values for DO for the East and West UNOX reactors at this time were 6.6 and 6.4 mg/L, respectively. This is indicated by the tags “W00-INIT-DO-EAST” and “W00-INIT-DO-WEST”. WestRock’s TSOP indicates that the target initial DO is 12-18 mg/L for the health of the biological organisms in the system. Karl Schumacher noted that DO results may be skewed due to sampling error. Sludge is recycled from the secondary clarifier to the UNOX reactor. WestRock’s TSOP states that the ideal recycle solids concentration is 10,000-12,000 ppm. The recycle return activated sludge was 13,040 ppm as indicated by the “WestRock Daily Environmental Lab Report” provided by Karl Schumacher, dated 2/19/2019.

Secondary Clarifiers Some pin floc was carrying over to the launder ring of the north secondary clarifier. Little to no blockage was observed on the weirs of the secondary clarifiers. Compared to the east side of the north secondary clarifier, the east side of the south secondary clarifier showed low flow (Figures 4 and 5). Karl Schumacher said that he was not aware of the weir ever being levelled. The walkway on top and around the secondary clarifiers only provides access to about one quarter of the perimeter of the clarifiers. Other sides of the clarifiers could not be observed. The effluent flow rate from the secondary clarifiers was 18.5 MGD, as estimated by the summation of the flow meter reading from WestRock’s intake of city fresh water and the flow meter reading of contact cooling water. The secondary effluent temperature was 95°F and had a pH of 6.4 (permitted at 5.4-9.0). The temperature in the compositor was observed to be 3°C (target 4°C). The sludge level in the north and south secondary clarifiers was 4 feet and 6 feet respectively, with a target of less than 10 feet.

Effluent Piping WestRock discovered a weep hole on their effluent piping on January 21, 2019. Repairs to the pipe were completed on January 29, 2019. The repair appeared to be in good condition.

Laboratory WestRock performs wastewater analyses at their on-site laboratory. WestRock’s lab is accredited by the Department of Ecology (Ecology) through October 31, 2019. They are accredited for analysis of chemical oxygen demand (COD), total suspended solids (TSS), pH, and carbonaceous biochemical oxygen demand (CBOD).

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CBOD and TSS values recorded in paper laboratory records were spot checked with data submitted to Ecology in the respective discharge monitoring report (DMR). Values in the paper laboratory records matched values submitted to Ecology. The TSS oven temperature was 104°C, within the target range of 103-105°C. The oven temperature is recorded daily as indicated by the “Tacoma Mill Effluent Worksheet” dated 2/20/19 provided by Paul Sponenburg, Laboratory Manager. The lab scale is tested daily against standard 50g and 2g weights. The scale is calibrated every 6 months, and was last calibrated December 2018. All pH buffer solutions stored in the laboratory were unexpired. pH meter calibration is tested daily. The pH calibration slope on the “Tacoma Mill Effluent Worksheet” dated February 20, 2019 is 99.9. Bottles of effluent are retained in the laboratory. Bottles of sample for February 15th through 20th were observed (Figure 6).

CONCLUSION I conducted a Class I inspection of WestRock on February 21, 2019. The tour of the facility included observation of the salt water cooling water intake structure, primary clarifier, UNOX reactors, secondary clarifiers, effluent piping, and laboratory. Process data for each treatment unit was also collected. The following observations and suggested improvements were noted:

- The cause of the sheen on the primary clarifier should be investigated and corrected. - Continue to monitor amp differential between drive motors on the primary clarifier rake

and investigate for potential problems if differential continues to exceed the recommended differential level.

- Sampling and analysis technique for DO should be reviewed to create more valuable process data to better inform operating decisions.

- The distribution of flow across the weir on the south secondary clarifier should be monitored and adjustments made, as necessary, to ensure proper treatment.

In general, the facility appeared to be operating in accordance with their NPDES permit. No enforcement action is necessary based on this inspection.

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Figure 1. Cooling water intake structure.

Figure 2. Sheen on the surface of the primary clarifier

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Figure 3. Primary clarifier weir and launder ring.

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Figure 4. North secondary clarifier weir and launder ring.

Figure 5. South secondary clarifier weir and launder ring, facing east.

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Figure 6. Bottles of effluent, 2/15/19-2/20/19