Water plants and pumping stations in Ho Chi Minh City need constant monitoring to ensure tap water for resident consumption is contaminant-free.

Approximately 90 percent of the Ho Chi Minh City population use tap water supplied by local water plants, including the Tan Hiep and Thu Duc water facilities.

To get a better understanding of the water monitoring process, Tuoi Tre (Youth) newspaper reporters paid a visit in May to Hoa Phu Pumping Station, a facility situated in Cu Chi responsible for pumping raw water from the Saigon River into Tan Hiep Water Plant.

Tan Hiep Water Plant, located in suburban Hoc Mon District, has a capacity to process 300,000 cubic meters of water each day and night.

In the plant, sophisticated gauging devices continuously monitor the water’s levels of opaqueness, pH, Manganese, and Ammonia, a colorless gas with a characteristic pungent smell.

Staff members keep a 24/7 watch on the monitors, being sure to catch any abnormalities and promptly notifying competent divisions for timely solutions when safety parameters exceed the allowed limit.

“We cannot afford to let our guard down. If abnormal parameters are left untreated, it could seriously affect the quality of raw water pumped into Tan Hiep Water Plant,” Vu Duy Hung, deputy head of Hoa Phu Pumping Station, said.

Recent water monitoring results revealed that the density of contaminants in the Dong Nai River, the country’s longest, was not a cause for concern, while contamination parameters taken from the Saigon River, particularly near Hoa Phu Pumping Station, oscillated unpredictably and showed worrying signs of escalation.

According to Tran Kim Thach, head of the water quality management division of the Saigon Water Corporation (SAWACO), organic pollutants, such as Ammonia and pesticide residues, pose the gravest concern.

Monitoring indices have indicated that the concentration of Ammonia in source water amounts to nearly 1 mg/liter at times, while clean water supplied to city-dwellers is supposed to be free of the chemical, he noted.

“Without proper treatment, Ammonia in clean water can combine with other substances and wreak havoc on consumer health,” Thach explained.

More chlorine must be added properly to treat Ammonia, or Ammonia may absorb most of the chlorine.

Apart from operating the water quality monitoring systems at the plants, staff members manually sample water from the Dong Nai and Saigon Rivers on a monthly and quarterly basis.

“Samples must be taken at a depth similar to that of the water plants’ water inlets, as samples of surface water do not truly reflect the quality of water pumped into the plants due to the presence of oil spills and other pollutants,” a water sampling officer explained.

The SAWACO water quality management division also collects samples from water near wastewater discharging factories along the Saigon and Dong Nai Rivers for analysis.

Salinity a major headache

Salinity is among the greatest problems faced by water quality monitoring teams.

Recently, salinity brought water plants in several provinces to a standstill, leaving locals in dire need of clean water for both themselves and their crops and cattle.

Seawater intrusion on the Saigon River also creates problems for the pumping station, causing the Hoa Phu facility to cease supplying raw water to Tan Hiep Water Plant about 10 times during this year’s dry season.

Saltwater also encroached on the Dong Nai River, temporarily disrupting production activity of Binh An Water Plant, located in Binh Duong Province, approximately 30 kilometers from Ho Chi Minh City.

A staff member at Hoa Phu Pump Station revealed that this year’s salinity level is unprecedentedly high and the bout is also worryingly lengthy compared to previous years.

To cope with the situation, water plant personnel have had to test salinity rates with manually operated devices to ensure maximal precision.

As the rate exceeded 250 mg/liter, the Hoa Phu station ceased operations altogether, leaving the Tan Hiep water plant in short supply of raw water.

Ho Thanh Binh, head of the plant’s technical department, recalled that they then turned to Kenh Dong Water Plant in Cu Chi District for a replacement supply of raw water.

There were times, however, that the Hoa Phu station and Tan Hiep water plant managed to circumvent the salinity bout to maintain the provision of clean water for city-dwellers.

“When the salinity rate exceeded 250 mg/liter but coincided with the tide peak, it would decline shortly after,” Hung, deputy head of Hoa Phu Pumping Station, said.

“We cut down on our pumping volume to maintain supply of water and made sure the salt water was diluted as regulated.”

Meanwhile, the Thu Duc Water Plant cluster, which feeds on water from the Dong Nai River and supplies 60-70 percent of the city’s entire volume of clean water, sought help from the Tri An hydroelectricity reservoir in Dong Nai Province, which discharged water to keep sea water at bay when the salinity rate in the Dong Nai River went beyond the permitted level.

Thach, head of SAWACO’s water quality management department, revealed that the salinity level in the Saigon River was on a continual rise from late December 2015 to late April this year, reaching up to 600 mg/liter at times.

To cope with salinity and other issues, SAWACO has proposed constructing a raw water reservoir capable of supplying water to the Tan Hiep water plant for two days whenever saline levels in the Saigon River rise above safety parameters.

The proposed reservoir is expected to boast a capacity of approximately two million cubic meters, and can be expanded to maintain supplies for between 10 and 15 days, Thach added.

The municipal People’s Committee has directed that SAWACO quickly conduct research on the project.

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