Wastewater woes

This 48-acre lagoon at the Clovis wastewater treatment plant started receiving water in November. The city agreed in May to accept water from Southwest Cheese, but nitrogen levels in the water have hindered the process. (CNJ staff photo:Andy DeLisle)

Nitrogen levels up to double the city standard have stalled plans for Clovis to handle Southwest Cheese’s wastewater.

In the meantime, Southwest Cheese has been applying 1 million gallons of treated wastewater daily over about 1,000 acres of cropland for about a year, Southwest Cheese President Maurice Keane said.

New Mexico Environment Department spokeswoman Marissa Stone said public health has not been compromised by Southwest Cheese’s irrigation practices, although the practices do not follow the cheese plant’s permit with the state.

In May 2006 the city agreed to accept the cheese plant’s wastewater. A permit NMED issued to Southwest Cheese reiterates the company must send a portion of its treated wastewater to the city.

City and Southwest Cheese officials assured the Environment Department in a Feb. 27 meeting they are striving to fulfill the agreement, Stone said.

“We believe (both parties) are doing everything possible to rectify the situation,” Stone said.

Engineering and treatment practices are being reviewed by Southwest Cheese to lower nitrogen in its wastewater, according to Robert George of the NMED Ground Water Quality Bureau.

The city limits Southwest Cheese to 10 milligrams of nitrogen per liter of treated wastewater, Stone said. That limit was set to comply with the state’s limit for nitrate, a form of nitrogen, in groundwater, according to Clovis Public Works Director Harry Wang.

Nitrogen content in Southwest Cheese’s wastewater hovers around 15 to 20 milligrams per liter, Keane said.

Every day, Southwest Cheese uses about 500,000 gallons of groundwater; recovers 500,000 to 600,000 gallons of water from milk; and treats about 1 million gallons of wastewater, Keane said.

Southwest uses its treated wastewater for operations, as well as irrigation of cropland it owns near the cheese plant, Keane said.

Keane said the treated wastewater is safe for irrigation purposes. The nitrate limit for Southwest Cheese wastewater is “as low as anybody has in the country,” he said, and nitrogen is natural fertilizer.

NMED does not have a uniform limit for nitrogen in wastewater discharges. Limits vary from 10 to 20 milligrams per liter depending on the depth of groundwater near wastewater discharge and other management factors. Crops soak up nitrogen, but as it filters through the ground, it can be converted into nitrate, a form of nitrogen that can be dangerous to health, according to George of the NMED Ground Water Quality Bureau.

The New Mexico Environment Department regulates nitrate in groundwater because excessive amounts can compromise the health of the young and elderly. Nitrate consumed in significant levels is tied to Blue Baby Syndrome, a condition that can lead to asphyxiation in infants, according to George.

The city sells its treated wastewater to a farmer, and the farmer uses it to irrigate his fields. If the treatment plant exceeds state limits for nitrate, excessive amounts of nitrate could seep into groundwater, which New Mexicans drink.

Southwest Cheese is regulated by NMED, as well.

“Any liquid discharge that has the potential to affect groundwater is required to be permitted,” George said.

The NMED permit issued to Southwest Cheese allows the company to discharge treated wastewater over 90 acres of cropland daily, and over another 679 acres in emergency cases for no more than 90 days per year when the Clovis Wastewater Treatment Plant cannot accept its water.

Passing Southwest Cheese wastewater to the city’s wastewater treatment plant benefits the company and the city, and protects water quality in the region, officials said.

Some contaminants remain in Southwest Cheese wastewater after treatment; by mixing it with city wastewater, which is treated to a higher quality, the wastewater rises to state standards, according to Clovis City Manager Joe Thomas.

The deal also gives Southwest Cheese an outlet for disposal of its wastewater and provides an arid region with water for irrigation and industrial purposes, according to officials.

Wang said the city is working with Southwest Cheese to bring its treated wastewater to city standards, and Keane estimated kinks will be smoothed out within a few months.

“It’s a matter of matching our needs with theirs,” Keane said.

But meeting the city standard for wastewater may be even more difficult for the company in the future. The city has made an agreement with NMED to lower nitrate in its wastewater below the state standard of 10 milligrams per liter, George said. That new standard will go into effect soon, officials said.

The 2006 agreement that forged the yet-to-be partnership between Clovis and Southwest Cheese simultaneously paved the way for almost $10 million in improvements at the Clovis Wastewater Treatment Plant. Those improvements were made possible through grants and low-cost financing from the New Mexico Environment Department. Southwest Cheese and the city are responsible for paying back NMED, Thomas said.

Improvements at the wastewater plant are under way, with 25 acres of new lagoons expected to be ready for storage soon, Wang said.

The city currently handles about 3 million gallons of wastewater daily.

Southwest Cheese officially opened in Curry County in October 2006. The company processes 2.4 billion pounds of milk each year, producing more than 250 million pounds of American-style cheese annually, according to its Web site.

The company employs approximately 225 people, its Web site reads.

By the numbers

3

Million gallons of water are treated per day at the plant on average

25

Acres of lagoons being added to water storage capacity

90

Acres in water storage capacity at plant before expansion

1987

Year the wastewater system was built