Brine management methods: Recent innovations and current status

Assessing the efficiency of a pilot-scale GDE/BDD electrochemical system in removing phenol from high salinity waters

Ion exchange technology remains the workhorse of various chemical, petrochemical, food, power, and pharmaceutical industries. The success of ion exchange process depends literally on understanding of its basic principles and applying them in a way suiting the nature of the treated feed. This chapter reviews the basic fundamentals and key components of ion exchange process taking into consideration the latest progress taking place in the field. The variation in the ion exchange materials, their nature, forms, and functions are reviewed. The kinetics, sorption equilibrium, operating modes, and engineering configurations for ion exchange processes are also discussed. A brief encounter for the various applications utilizing ion exchange processes is also presented.

Introduction to Ion Exchange Processes

Research and technological developments are being pursued vigorously all over the world to reduce the cost of desalinated water. Thermal and membrane-based desalination processes are very well known and plants are being operated to augment the demand of fresh water essential for drinking in water-scarce countries and to sustain the industrial processes. Any further improvement in energy reduction can only be marginal considering the complexity of the desalination system. The alternative approach is to add value by recovering edible salt, rare and valuable metals, such as caesium, titanium, uranium and vanadium, from the reject brine streams. In this regard, a novel polymeric chelating resin was designed and developed in Desalination Division, BARC laboratory with significant potential for this achievement. In this paper, the characteristics and potential of the resin have been described for the recovery of valuable elements based on experimental findings.

Strategy of deriving 'wealth from waste' from concentrated brine of desalination plant

“In-House” resin Polyacrylhydroxamic acid (PHOA) has been synthesized and utilized targeting ground water remediation; recovery of uranium from low concentration aqueous solution e.g., mining activities related water, flooding of excavated or deplumed areas, nuclear plant washed effluent and process generated effluents in nuclear plant during front-end as well as back-end treatment. In the present study, treatment of field effluent containing heavy metals and radio-nuclides from contaminated mining sites reflected preference for uranium with respect to manganese. The specific complexation between the extractant and metal ion especially uranium provides high distribution co-efficient (Kd) for uranium (Kd,U = 1,450 mL/g from inlet of Effluent Treatment Plant (ETP) and Kd,U = 74,950 mL/g for synthetic solution) compared to high level impurity (1,000 times higher concentration) of manganese (Kd,Mn = 111 mL/g from inlet of ETP and Kd,Mn = 10,588 mL/g for synthetic solution). The “In-House” resin showed significant extractability (70–95% elution efficiency) and indicates a possibility of selective removal/recovery of the valuable metal ions even from secondary sources. As a specialty, resin can be regenerated and reused.

Studies on uranium recovery from inlet stream of Effluent Treatment Plant by novel “In-House” sorbent

The act of enrichment or improving the quality of product concentration, i.e. 'pre-concentration', has been studied with respect to uranium plant effluent, which contains uranium in 10?30 ppm level intermingled with a huge number of interfering ions, such as magnesium, in percent level. The effects of different operating conditions, such as concentration of uranium in the effluent, pH, the time required for uptake of uranium and the effect of the presence of other elements in the effluent, in batch experiments have been investigated. Using this in-house novel resin for preferential uranium uptake, the sorbed matrix has been eluted with different eluant concentration for further enrichment of radionuclides in the elute. High uptake values for uranium ions prove its selectivity, and fractional elution ensures further reuse of sorbent and significant improvement in uranium enrichment.

Recovery and pre-concentration of uranium from secondary effluent using novel resin

The cost of product water is a key factor in determination of acceptability of any desalination system and plant. In case of Sea Water Reverse Osmosis plants, most of the energy consumed is in the form of electricity. The High Pressure Pump (HPP) is the single major energy consuming equipment with a share of above 75%. Hence reduction in energy consumed by HPP will have a substantial effect on the overall energy consumption. The high starting torque requirement of high pressure pump results in increased acceleration time of the motor which subsequently increases the strain on the upstream electrical system from motor feeder to transformer. Provision of a Variable Frequency Drive can be a solution for both the above problems. This paper studies the techno-economic feasibility of providing variable frequency drive for HPP motor at NDDP, Kalpakkam.

Techno-economic feasibility study of providing variable frequency drive for high pressure pump, SWRO plant at NDDP, Kalpakkam

Process control is an essential part of the desalination industry that requires to be operated under optimum conditions to increase the lifetime of the plant and reduce the unit product cost. Improved process control is a cost-effective approach to energy conservation and increased process profitability. The Multi-Stage Flash (MSF) plant involves many complicated operations related to steam, chemicals and seawater. These include variable capacity, slow dynamics, deadtime characteristics due to certain load changes, significant effects of small deviations from design conditions on plant operation, effects of power plant output conditions on the desalination plant, instability due to disturbances in steam supply and water temperature variations. Keeping in view the above criticalities, the selection of an effective control system becomes inevitable. This paper aims at identifying various types of control loop available in an MSF plant, selection of control elements, type of control strategy needed for it and integrating the whole system for supervisory control.

K.L. Thalor

Papers

Strategy of deriving 'wealth from waste' from concentrated brine of desalination plant

Recovery and pre-concentration of uranium from secondary effluent using novel resin

Techno-economic feasibility study of providing variable frequency drive for high pressure pump, SWRO plant at NDDP, Kalpakkam

Process control in multi-stage flash desalination industry