Compact and efficient Danfoss pumps solve Chinese wastewater treatment rules

China’s recently-enacted ZLD laws demanded fast action from Shenhua Ningxia Coal Group managers. To be in compliance, they had to cease all wastewater discharge from their coal liquification plant, and they had to do it quickly.

To complicate matters, the wastewater treatment plant would have to consist of a range of systems for different treatment purposes and be housed within existing premises. This meant that the treatment plant had to be as small as possible in order to fit inside a building already in use.

To maximize filtration efficacy and energy efficiency, Beijing New Biolink’s engineers designed an array of four systems: two to purify NaCl wastewater, a third to purify Na₂SO₄ wastewater, and a fourth for nano-filtration. Each system had its own requirements for pump quantity, flow, and pressure.

Although engineers considered a variety of pump technologies, including plunger pumps, they chose APP pumps from Danfoss for multiple reasons.

“Since we had to fit the entire wastewater treatment system inside an existing building which was designed for something else, the footprint of plunger pumps was problematical,” says the Chief Engineer from Beijing New Biolink. “Furthermore, the low pulsation of the Danfoss pumps significantly reduces vibration, plant complexity, and costs. But delivery time and reliability were also very important. The Chinese government demands full compliance with the new ZLD legislation, so we had to make a tight deadline and ensure ongoing pump performance, without which the entire plant would have to shut down. Danfoss APP pumps were the logical choice for all of these  reasons.”

The new wastewater treatment facility went online in March 2019. As expected, it has run without incident since.

“The reliability of these APP pumps is high, and service intervals are long,” explains the Chief Engineer. “Staff at Shenhua Ningxia Coal Group were pleasantly surprised at the system’s compact footprint, and managers are happy that everything came together on time and on budget.”