In view of maintaining the safety of farmland use in the County by preventing the source pollution from entering the irrigation waters and subsequently tackling the problem of using such water to irrigate farmland and causing pollution thereto, the existing audit and control work on water polluting sources will continue in addition to the setup of water automatic continuous monitoring stations in the concentrated areas of farmland pollution to expand the waters control areas, and the review of the executive results in the heavy metal total amount control areas set in 2016 by the County. An assessment was also made in amending the scope of total amount control areas or expanding the overall planning on the definition to address the issue of relocation of polluting sources in recent years after the control areas were defined. Since 2006 additionalwater automatic continuous monitoring stations were set up, and in 2013 audit on the water polluting sources was reinforced, employing scientific checking methods complemented by scientific instruments as well as a joint investigative mechanism formed by the environmental, prosecutor, police and investigative departments, to strengthen law enforcement. Also, since the announcement of defined heavy metal total amount control areas in 2016, till date effectiveness has been seen in deterring illegal discharge of business wastewater (and polluting water). in order to continue the improvement on the waters and farmland heavy metal pollution in Northern Changhua, the effective management of the waters in this regions became very important to the sustainable use of the controlled farmland and the maintenance of the whole environment quality in the County. The execution of this project is hoped to serve to crack down the water polluting sources, reduce and prevent the monitored waters from being further polluted, and ensure the environmental quality and water in the irrigating waters within the County’s jurisdiction.
The executive period of this project was from the day (Sept. 24, 2021) following the government bid awarding date to Mar. 23, 2023. As of Mar. 23, 2023, the tasks under this project were all completed according to the tender specifications and the contractual schedule of this project, a 100% execution rate. Current achievements of this project are summarized as follows:
1.Flow survey in total amount control areas and analysis of heavy metal changes contained in receiving waters
To have an understanding of the executive results in the Dongxi 2nd and 3rd Ditches and Babao 1st Ditch total amount control areas published by the County, this project will analyze the executive results after that announcement and assess the outcomes of pollution reduction in respect of the reduction of heavy metal polluting load in receiving waters and the rate of meeting water quality standard for heavy metals in irrigation water, to facilitate the submission of the assessment report of executive outcomes to EPB. In addition, in line with the review of executive outcomes in total amount control areas by EPA’s toal amount control evaluation mechanism, an outcomes assessment report will be submitted before the project ends. As of Mar. 17, 2022, the survey on cross-sectional flow in receiving waters in 15 total amount control areas was completed, and two reports on heavy metal water changes in receiving wtaers, irrigation water standard compliance, and total amount changes in waters before and after the announcement of total amount control areas were submitted.
As of Mar. 2023, the statistics showed that in 2022, of all 36 monitoring stations in Dongxi 2nd and 3rd Ditches and Yangzicuo River, a total of 32 stations met the irrigation water standard for heavy metals, all reaching a 100% achieving rate, with only Fanya Ditch Drain, Niuchouzi Drain, Yangzicuo Bridge and Jiali Replanned 29th Area failing to reach 100%. In terms of achieving the environmental standards for human health protection, a total of 29 stations reached 100%, with only Fanya Ditch Drain, Niuchouzi Drain, Yangzicuo Bridge, the intake in Dabian Branch, Jiali Replanned 29th Area, Sanjiachun Drain and the unnamed bridge on Sec.6 of Xiandong Rd. failing to meet the standards. The achievement rate in terms of concentration of heavy metal pollutant conce was improving at most stations during 2011 to 2023, meaning total heavy metal amount in receiving waters were decreasing each year, which in turn increased the reduction of heavy metal pollutants at the stations, making it possible to reduce heavy metal pollutants entering receiving waters and successfully decrease their discharge into drains and ditches. Otherwise, when the water was used by farmers for irrigation, the farmland would have been polluted by heavy metals; thus, the decrease in hazards of heavy metals to biology was expected. in the future strengthened audit will continue on the businesses upstream of a small number of stations that failed to continually make the achievement rate; water improving measures will also be driven in view of continually achieving the goal of water quality improvement.
According to Guidelines for total amount control evaluation and explanations on criteria for evaluation under EPA’s “2022 program of evaluation of water pollution control”, the points earned in the key items of evaluation added to 25, which resulted in 20 points by the scoring method of the evaluation program, which entitled the County to 1.5 points for water pollution control evaluation program.
2. Assessment of potentially heavy metal polluted areas and expanded total amount control areas in Northern Changhua
To assess potential heavy metal pollution areas and expanded total amount control areas in Northern Changhua, surveys were conducted on the heavy metal s discharge by the highly potential polluting businesses in the vicinity of the published total amount control areas. there were 51 businesses under survey, of which 49 were in operation in respect to on-site operation, and another 2 were applying for change in wastewater producing processes in on-site process and no heavy metal wastewater was produced. of the 49 with process operation, 24 (10 metal surface treatment operators and 14 electroplators) were found with the concentration of specific heavy metals tested in original wastewater reached 90% of the effluent standard; the survey result on these 49 businesses was taken as reference basis for assessment of explanded total amount control areas. in addition, under this project, based on the synthesized data and the 2018 survey results with time-lapse resin capsules (hereinafter called the Capsule), 123 sets of Capsule were deployed at appropriate locations selected in the areas near Fanya Ditch Drain and Yangzicuo River; the results indicated that the locations with higher content of heavy metals were mostly the water resources taskforces of Lugang work station in Xiaoxin Ditch, Xin Ditch, Xinpi Old Ditch and Gouliao Ditch, which were scattered mainly in the areas south of Fanya Ditch Drain and near Toulun Drain and Yangzicuo River. furthermore, given that the water in irrigation channels within the published total amount control all met the standard for irrigation water in recent years and that there was a tendency of decrease in both the number of businesses with heavy metals and the amount of pollution discharge, this project proposed to modify the ways of total amount control based on environmental background data and Capsule analysis results: to modify the way of control of businesses upstream of Grade-1 total amount control areas for those new and existed businesses and to maintain the way of control of Grade-2 total amount control areas. as to the areas outside otal amount control areas, because the polluted farmland still accounts for a certain proportion of the entire County while concentrating in Lugang work station, as well as there is still concern about exceeding standards by the irrigating sources, in order to let the control effectiveness sustain, this project proposed to assess the expanded total amount control; that is to bring on new ways of Grade-1 total amount control for new and existed businesses in the expanded total amount control areas, to effectively control the farmland pollution. in addition to that, to adjust, in a rolling manner, the grades of potential of canal heavy metal pollution, whereby to decide the locations for prioritized water automatic continuous monitoring stations; and finally, three locations were selected: Gouliao Ditch, Shuzijiao Drain and Pitou Drain, with invitation given to the land owners to join the site survy meeting. The operation of setting up 3 water automatic continuous monitoring stations was completed on Mar. 21, 2022. After an initial survey, under this project, on the 3 new monitoring stations on Apr. 19, 2022, as of Mar. 2023, 144 instances of maintenance ＆ service and 36 calibrations were performed at these 3 stations, in addition to the submission of monitored data (pH, EC and T) from a total of 12 instances and a comprehensive analytic report on abnormal times throughout the period of operation maintenance to EPB to maintain the accuracy of station data and continue upload to the real-time monitoring platform steadily for EPB to keep updated on the changes in the water in highly polluting potential canals.
3. Survey on heavy metal discharge of the unlisted businesses
The purpose of the survey on heavy metal discharge by unlisted businesses was to ensure of the consistence with the classification and scope of definition for factories and business under water pollution control act. in case any one that was confirmed by checking within the definition of business under water pollution control act, we assisted in preserving the evidence on site and notified EPB personnel to deal with on site, where any one suspected to pollute nearby or downstream farmland was put in a list for submission, along with the checking results, to the agencies governing soil remediation for further disposal. The execution of this project covered 50 instances; as of Mar. 17, 2023, these were all completed (a 100% achievement rate). The checking results showed 10 businesses met the definition of business under water pollution control act, which were all diposed by EPB, and of which 8 were fully disposed as stopping operation, and 2 being disposed; the total amount of disposal was NT$666,000. Of the 10 businesses, 2 were established with approval by the competent authority of business, of which 1 situated in Grade A total amount control area has been ordered to stop operation by EPB, and the other 1 outside total amount control area had changed its process to dry operation without wastewater produced when EPB made a follow-up check on site. The EPB will make follow-up check on these 2 businesses from time to time to see if they really stopped wastewater-producing operations as stipulated. Of the 8 businesses not approved by the competent authority of business, 4 were situated within Grade A total amount control area, of which 3 have been ordered to stop operation and 1 being disposed; of the remaining 4 businesses outside total amount control area, 3 were ordered to stop operation, and 1 has currently applid for the issuance of relevant evidencing documents.
4. multiple Graded audits on controlled businesses in potentially highly heavy metal polluted areas
(1) Grading of the subjects of checking
In order to cause the controlled businesses in the County to increase the efficiency in the handling of pollution discharge and the operation quality, checks of different intensities were conducted on 72 controlled businesses situated in highly heavy metal pollution potential areas: case-specific check on 12 businesses of grade-1 targeted polluting sources and check with flaw counseling on 60 businesses of grade-2 potential polluting sources, where the checks of different strengths served to effectively manage and improve the pollution to waters in the County.
(2) Case-specific checks on grade-1 (targeted polluting sources)
In case-specific on-site check on the 12 businesses of targeted polluting source, we found 9 in violation of the water pollution control act, which were all subjected to completed disposal, with fines totaling NT$3,755,800. A majority of the administrative faults found in on-site check was “fault of water meter records”, found in 6 businesses (a 50% fault rate); that was because some of them failed to keep daily records properly, or failed to save the records at the site, and made mistakes in conversion of the records of water flow which led to inconsistence between reported value and the records kept on site, or changed water meters (without making records) which led to incorrect input when reporting the data. In terms of legal fault, the most businesses, 8 of them, were found with the fault of failure of “measured operation parameters” to match the permitted value, (a 66.7% fault rate). Of the 12 targeted businesses, 10 were found with pollutant concentration in original wastewater exceeding the maximum permitted log (an 83.3% fault rate); 11 with faults in wastewater treatment facilities and operation (a 91.6% fault rate); and 6 with effluent (pond) water quality failing to meet effluent standard (a 50% fault rate). Counsel was given to them for improving the faults, with timelines given for submitting their improvement plans. Presently the improvement plans of 12 businesses have all been reviewed. Considering every method of improvement, 11 were to improve on site, 6 were allowed to propose changes, 5 were to improve the engineering, and 1 stopped operation; the fund committed to improvement totaled NT$960,130. The personnel of this project conducted on-site follow-up on the details of fault improvement on 12 businesses, of which 1 metal surface treatmer operator autonomously reported operation stoppage and was applying for control delisting. Of the remaining 11 undergone follow-up on improvement, 3 have not yet completed their improvement. The improvement yet to complete included legal compliance in 1 business, and wastewater treatment facility operation in 3; the remaining 8 businesses have completed their improment of the faults. it is recommended to take the 3 bussinesses failing to complete their improvement as subjects of future check on high heavy metal risk for reference basis.
(3)Check on fault counsel on grade-2 potential polluting sources
On-site checks on 60 businesses (93 instances) of potential polluting source found 6 in violation of the water pollution control act, of which 5 were completely disposed, with fines totaling NT$681,000. In term of fault of records inspected on site, sludge production/clearance/deposition records “imcomplete” in 8 businesses was the most (a 13.3% fault rate); in terms of fault of non-material pollution, “reservoir ＆ pipeline marking” was the most, found in 25 businesses ( a 41.6% fault rate). In terms of wastewater treatment facility operation, the “measurement operation parameters” of pretreatment units and non-matching to permission was the most, in 10 businesses (a 21.3% fault rate); failure of effluent (pond) water to meet effluent standard in 21 businesses (a 40.3% fault rate); in terms of non-compliance, the largest number of businesses with the common items (pH, suspended solids, COD) was 19. Targeting the faults found on site, counsel was given on site to the businesses in improvement, with timelines given for submitting the improvement plans. A total of 50 bussinesses should submit improvement plans, which have all been reviewed the the project’s personnel. the number of businesses promising to improve on site was 48, and that to file permit changes was 11. The 60 potential polluting sources, which this project’s personnel have inspected the wastewater treatment facilities (visual faults, operation parameters), and quality of effluent (or the last unit), together with an analysis of on-site fault of legal compliance, were divided in four grades for follow-up. As of Mar. 17, 2023, counsel was given to 50 businesses to present improvent plans on the faults found by the check on potential polluting sources, of which 15 should only be confirmed with their improvement plans. these 15 businesses have all been confirmed by our coworkers in this project to have completed the improvement (a 100% improvement rate), with the remaining 35 businesses that should be re-checked on site. follow-up check found 1 metal surface treatment operator still failing to complete the improvement on the effluent (exceeding effluent standard).
5. Execution of tasks on responding mechanism for water anomaly in northern Changhua water monitoring network
To protect the water quality of the irrigating waters in the County and avoid the farmland from heavy metal pollution, the EPB set up 16 water automatic continuous monitoring stations in potential heavy metal polluting areas in northern Changhua. That works by monitoring water quality in canals of high polluting risks with 24-hour instant monitoring operation and low-power data recording units and Big Data analysis, more effectively zeroing in the time when polluting sources are caused and the characteristics of water quality. Thus, EPB can effectively deter illegal discharges by the businesses that result in pollution to waters, and decrease and prevent the monitored waters from being re-polluted, as well as ensure the environmental quality and the water quality in irrigiating waters in the County.
Under this project, we had carried out the grading of monitoring stations and polluting sources before the response tasks to water anomalyes in northern Changua’s monitoring network; we then carried out the on-site response tasks in different ways of response and checking based on the grading results, and made rolling correction on that results with respect to monthly monitored data. By the grading results, “case-specific check on polluting sources” was performed on 9 businesses, “check on wastewater treatment facility operation at polluting sources” on 7 businesses, and “ordinary check on polluting sources” on 13 businesses. As of Mar. 17, 2923, under this project, 80 patrols were made on the 16 stations, totaling 365 instances, including the case-specific nocturne check on 3 stations on Mar. 31, 2022, which found 12 businesses with material pollution, which were disposed by EPB for fines totaling NT$3,514,336, in addition to the counsel given in 23 instances for improving on-site faults.
The statistics on the results of audit, disposal and counsel showed that in terms of effluent pollution reduction, the greatest reduction was COD at 71,378.2 Kg per annum, and in the category of heavy metals, heavy metal copper (741.8 Kg/year) was the most; the amount of effluent pollution fee shifting was estimated ato NT$2,149,910/year. A statistics under this project on the decrease in abnormal pH records at the existed 13 stations in 2021 and 2022 (the 3 new stations not taken into statistics for now) revealed that Xinzhuangzi Drain monitoring station remained with 0 records, 8 stations (Niuchouzi Drain, Shuiliougong Watergate, Citongjiao Drain, Xiabu Drain, Fanyagou Drain, Andong 2nd Drain, Toulunpu Drain and Xindongshan Drain) had increased records of abnormal pH between 46% and 100%, with other 4 stations without apparent decrease in the records of abnormal pH. We recommend for taking these 4 water monitoring stations (Jiousanjiacun Drain, Jiali Replanned 29th Area, Sec.2 of Changyuan Rd. and Hemei Drain) as reference basis for future rolling correction of grading of station and polluting source, to help in subsequent continuous control of the polluting sources upstream of the 16 water monitoring stations.
The complex drainage system and irrigation system cause the presence of potentially toxic substances and their impacts on soil. Environmental concern of a group of materials is heavy metal accumulation in soil, threatening food security and terrestrial ecosystems. This issue is a systematic problem in Changhua County due to the intervention of drainage in irrigation canals. To prevent the impact of heavy metal pollution on paddy soil, this project assessed the feasibility of pollution early warning, resolved the effect of sediment on irrigation water, and measured the accumulation of heavy metals in paddy soil, from the perspectives of the drainage basin and sediment management. Eventually, the data extraction and field experiment results feedback to ameliorate management suggestions.
Extracting information from continuous monitoring and sampling water for measuring heavy metal was performed to assess the pollution. The periods of irregular data were rapidly screened with the Intensity-Time Chart visualizing the data from 2020 to 2022 of 13 continuous water quality monitoring stations. Then, 50 water samples were collected and analyzed. By integrating the data of water samples and influential regions of the water canal, 13 stations were prioritized from strategy I, with the highest risk, to V, with the lowest risk.
To resolve the effect of sediment on irrigation water, continuous monitoring of irrigation water amount and field sampling were applied. In 12 consecutive months, the water level was monitored, and the corresponding rating curves were developed in five stations in the testing canal, where the total water flow ranged from 422,000 to 635,000 m3.
As irrigation water is the main candidate for contributing heavy metals to the paddy field, the relevant components, the inflows of suspended solid and the canal sediment, were collected and analyzed; meanwhile, the accumulation of heavy metals in paddy soil after two growing periods (February to November) also measured. Inflowed suspended solid that an interceptor, installed at the entrance of the irrigation water, collected contains high Cd, Cr, Cu, Ni, and Zn. If irrigation applies continuously, the sediment-carried heavy metal may accumulate in paddy soil and result in heavy metal pollution. Besides, the soil heavy metal measurements show a clear increase in Cr concentration in two paddy fields along the selected canal; therefore, Cr might be one of the concerned but low-profile heavy metals in the experimental zone.
Eventually, together with the initiative of protecting paddy soil, the result of this project evolved into a synthetic strategy. In the suggestion, systematically characterizing effluent from industries, inventorying the confluence of wastewater, manufacturing management map, managing or treating polluted canal sediments, apportioning source of heavy metals in suspended solids, and mitigating suspended solids by closing irrigation gate are documented. Further, paddy field management or adaptation can refer to the theoretical increments of heavy metal in paddy soil, supported by the field data and inflow estimation.
