The circular economy is an industrial system designed for recovery and regeneration to replace “end of life” with “recovery" in order to turn waste into resources and thereby achieve waste reduction. By constantly implementing the circular economy, we implement water conservation and drainage reduction through improvement programs to reclaim and recycle valuable water resources for reuse and set the annual water conservation target at “1%". The actual conservation in 2021 was 4.26%. The boundary of water resource and effluent management is the Kaohsiung Plant, with data coverage of 100%.

In terms of water stress distributions, based on the water stress by country in the ‘Aqueduct Water Risk Atlas’ published by the World Resources Institute (WRI), the water stress of Taiwan falls at the low to medium level, with water stress at 10-20%.

According to the 2020 water resources statistics published in the Water Resources Agency Register Statistical Report, MOEA, the water consumption of Kaohsiung City was 280,439 Ml, including 94,101 Ml of water for domestic use or public use, 85,677 Ml of water for industrial use, 80,177 Ml of water for agricultural use, and 20,485 Ml of water for other uses. The 2020 total water withdrawal of Kaohsiung Plant was 1,029.036 Ml, accounting for about 0.4% of Kaohsiung City’s total water consumption. USI withdraws water mainly from tap water supplied by the Pingding Waterworks and Cheng Ching Lake Waterworks for product production, equipment cooling, boiler, domestic use of employees, and other uses. Compared to 2020, water withdrawal in 2021 reduced by about 31 Ml to 998.098 Ml.

2021 Water Withdrawal, Discharge, and Consumption

★ Water conservation and reclamation

Following the rising water demand, escalating climate change impact, and expanding sustainability pressure, we keep a constant track on water shortages and endeavor to reduce water consumption or enhance water reclamation in response. When the water shortage was severe in Kaohsiung during April-May 2021, the Kaohsiung City Government rationed water supply for industrial use by 7% at phase I and 11% at phase II. In response to the government’s industrial water rationing policy and promote water conservation and consumption control, we advocated the cessation of using tap water for irrigation, washing building exterior walls, cleaning ditches, washing cars, and taking shower, which would consume more water. We also enhanced leakage inspection of pipelines and control valves to save water across the plant.

★ Water Efficiency Management System

In 2021 we implemented the ISO 46001:2019 Water Efficiency Management System and completed system certification in February 2022. By inventorying the current status and ways of water consumption across the plant, through identifying, planning, managing, and improving the risks and opportunities of water with systematic water consumption management, and thereby optimizing water demand management, we effectively achieved the goals of water conservation and discharge reduction to enhance water efficiency and reduce water costs.

In 2022, we will enhance wastewater system management and optimize operation to reduce wastewater discharge and increase wastewater reclamation up to 12,000 MT (projected). We will also implement process improvement and reduce MRT steam use to save water up to 2,880 MT/year (projected).

★ Water as a shared resource

In 2021 we planned the firewater connection project with the plants (Grand Pacific Petrochemical Corporation) in the nearby Dashe Industrial Park. Besides dispatching water to support firefighting through water as a shared resource, this also strengthened the emergency response capability. Currently, Grand Pacific Petrochemical Corporation has connected firewater with TSRC Corporation in a firewater storage tank of about 4,500 m3. Currently, the effective capacity of our firewater storage tank is 4,297 m3. After the completion of the connection project at the end of 2022, the total volume of firewater as a shared resource will be about 8,797 m3.

Wastewater from the plant is the main source of effluents from USI. According to KSEPB’s effluent runoff discharge permit, effluents that cannot be refused after treatment and comply with the environmental protection laws and regulations can be discharged to the surface water body—Houjing River. According to the data of the Soil and Water Pollution Control Division, Kaohsiung Bureau of Environmental Protection, the 2020 discharge of the effluent catchment of the Houjing River was about 77,280 CMD, including 58,832 CMD of domestic sewage, 18,341 CMD of industrial wastewater, and 107 CMD of livestock wastewater. The approved discharge of USI Kaohsiung Plant is 980 CMD, accounting for about 5.3% of the industrial wastewater at the effluent catchment of the Houjing River. The total discharge in 2021 was 305.265 Ml.

Wastewater discharge from the plant includes process wastewater and domestic wastewater from employees. Wastewater is transported to the water treatment plant for treatment via wastewater pipelines. The wastewater treatment system includes the pre-treatment and primary (physical) treatment. Through trash screening, oil removal, sedimentation, and chemical treatment, and the sludge treatment unit for wastewater solid-liquid separation, effluents meet the drainage quality before discharge.

To reduce the environmental impact of discharge and promote waster recycling and reuse, besides complying with environmental protection laws and regulations, we optimized the functions of the wastewater (sewage) treatment plant in 2020, including adding the sludge concentration tank, improving the bottom sludge removal system of the sedimentary tank, and building the sludge rinsing system for the flotation system to enhance sludge treatment and collection efficiency. In 2020-2021, we constantly added major separator valves and sampling points to effectively block and control abnormal wastewater leakage to reduce the load of the treatment system and lower the environmental impact of effluents to achieve process source control.

Every half a year, we hire environmental analysis organizations approved by the Environmental Analysis Laboratory (EAL) to examine water quality of effluents from our plants, including NH4 required for total volume control. Every year, effluent test items required for reporting are well-followed the effluent standard. According to previously amended and promulgated “ Effluent Standards ”, the water quality control of discharge from the petrochemical industry includes 22 items, including 7 general water quality items and 15 specific water quality items. In our 2020 untreated wastewater and effluent quality tests and analysis, the measurement of 11 specific water quality items were below the method detection limits (MDLs). Hence, the inspection for these 11 items was exempted after reporting to the Bureau of Environmental Protection. In 2021 we continued to enhance the operation of the wastewater treatment plant, and the all water quality items of discharge complied with the regulatory limits.

Additionally, after discharging effluents to the Houjing River in Kaohsiung, a NH4 total volume control area, the NH4 detection limit is below the regulatory requirements over the years. According to the inspection data during January-April 2021 of the Kaohsiung Bureau of Environmental Protection, the detection limit of NH4 at the Houjing River was 11.68 (mg/L). The 2021 NH4 value of the Kaohsiung Plant was far below the effluent standard, with the lowest detected value at below 3.9%.

Results of Water Quality Examination in Last 3 Years