IN THE FIELD
key component in the system that works to reduce energy consumption, and can provide as much as 60% energy savings in an RO system. It works by harnessing the pressure energy of the high-pressure reject brine and transferring it to the incoming feed flow, thereby reducing the flow through the high-pressure pump. Five skids were equipped with the turbocharger, and one skid with two PX 70s. Turbochargers enhanced the plant’s productivity and improved energy efficiency, capable of operating at pressures of up to 45bar. The PX 70 devices were incorporated in one skid alongside disc membranes to optimise energy consumption and provide flexibility to handle variable feed chemistry. By reducing the volume of water going through the high-pressure pump, the use of a PX 70 also allowed the plant to be designed with a smaller capacity high-pressure pump, reducing capital expenditure. The Aquabold high-pressure pump is a multistage centrifugal pump that can pair seamlessly with either the turbocharger or PX to drive feed flow at a rate of up to 280m 3 /hr. This multistage approach reduced the stream volume sent to the thermal system, achieving ZLD and eliminating the need for effluent to be sent to an evaporation pond. THE RESULT The energy recovery devices were critical to address the variability and rise in total dissolved solids (TDS) and temperature. With salinity expected to fluctuate from 15,000-20,000ppm, the varying feed chemistry of the tannery waste stream posed a challenge to membrane systems and pumping equipment. During the initial commissioning in 2011, the Energy Recovery service team provided expertise on the ideal configuration and requirements of the RO system to prevent any stalling and the plant has been in operation ever since. Currently, the TDS can rise up from 15,000-20,000 parts per million (ppm) with little to no effect on the equipment.
PX 70 installed in the Ranitec CETP (Image: Energy Recovery)
enhance membrane operation even with variable operating conditions through flux balancing, resulting in higher recovery rates of the membrane system with a more concentrated effluent. The concentrated brine stream allowed for a smaller thermal evaporation process and Ranitec was able to realise a 60% capital expenditure reduction on the thermal process and other system components, and 30% operating expense savings. Due to these savings, the CETP achieved a payback period on the Energy Recovery solutions of under two years, with savings on operating expenses projected to increase as the TDS concentration rises.
PX. By integrating these products into our wastewater treatment process, we reduced our energy consumption by a significant margin,” said a managing director of the Ranipet Tannery Effluent Treatment Company. The design, construction, and continued operation of the Ranitec CETP has been recognised for its quality and efficacy. It is India’s first CETP to be certified to ISO 9001, an independent international quality rating standard. The plant is also the first in the leather manufacturing sector to be certified to ISO 14001, which measures environmental management systems. Additionally, the treated freshwater is being recycled back to the 92 member tanneries, reducing their reliance on the local water supply, operating costs, and alleviating demand in the region for a scarce resource. Finally, the efforts prevented further pollution of Ranipet by eliminating discharge of effluent. Reference 1 International Energy Agency. The changing landscape of global emissions. <https://www.iea.org/reports/co2- emissions-in-2023/the-changing-landscape-of-global- emissions>
The facility saves an estimated 1,058,500kWh annually due to the
reduction in energy consumption, which translates to annual operating expense savings of an estimated US$70,361. The reduction in energy usage also prevents an estimated 500 metric tonnes of carbon emissions from entering the atmosphere each year, which is equivalent to the emissions of 250 Indian citizens. 1 “We are delighted with the performance of Energy Recovery’s turbocharger, Aquabold high-pressure pump, and the
Energy Recovery’s solutions for this multistage RO CETP system are helping to
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