The EPA subsidized the Chiayi County Government to carry out the Budai Township- Yanguan Drainage Water Purification Project, which can treat up to 460 metric tons of wastewater per day. Located near the Budai Fishing Port, which is downstream of Jianlong Borough and the Yanguan Drainage System, the project was completed on 16 May, effectively resolving a long-standing issue of odor and poor water quality caused by wastewater from pickling vegetables.

The Yanguan Drainage System in Chiayi County collects mainly household wastewater from Jianlong Borough in Budai Township, which is an area with a high concentration of dried daikon producers and the most significant pickled daikon production area in Taiwan. The pickling process generates a large amount of wastewater, and during the winter season when daikon is harvested, a significant amount of pickling wastewater flows through the Yanguan Drainage System, causing water quality deterioration and foul odors that have been troubling residents for many years. To improve the quality of the residential living environment, ameliorate the wastewater pollution and ensure the water quality of the downstream Budai Fishing Port, the EPA subsidized the Chiayi County Government to carry out the water purification project in 2020. The total budget exceeded NT$88.09 million, with the EPA subsidizing over NT$70.47 million and the Chiayi County Government bearing over NT$17.61 million.

Considering the difficulty of treating high-salinity wastewater, this project adopts a diversion method to mix and dilute household wastewater. It utilizes a two-stage contact aeration oxidation process for treatment, with a daily processing capacity of 460 metric tons. After a 3-month trial operation, the average removal rates of biochemical oxygen demand (BOD), suspended solids, and ammonia nitrogen reached 96%, 89%, and 83% respectively. The results have been excellent, successfully resolving the long-standing issue of pickled daikon wastewater pollution. The foul odor has disappeared, the unique agricultural culture of Chiayi preserved, and the residential quality of life improved. The purified water is returned to the Yanguan Drainage System, enhancing the overall water environment of the downstream Budai Fishing Port. Additionally, solar photovoltaic panels were installed on the roofs of the treatment facilities and sludge drying beds, providing a portion of the electricity needed through green energy, increasing land utilization efficiency, and reducing carbon emissions.

In addition to achieving the goals of higher water quality and sustainable green energy generation, the treatment facility also successfully showcases a win-win situation for both industry and environmental protection, while revitalizing the waterfront scenery at Budai Fishing Port.

Excerpt from Major Environmental Policies, May 2023