Nanofiltration/reverse osmosis for treatment of coproduced waters

Reaction kinetic model for a recent co-produced water treatment technology

With the increasing demand for fossil based energy and implementation of progressively strict environmental pollution control standards, treatment of a large amount of co-produced waters (CPWs) from fossil based energy production has become increasingly important. Removal of bicarbonate with H2SO4 has been recently studied as a simple and cost-effective method to decrease the alkalinity of CPWs. The present work investigates the kinetics of the reaction between H2SO4 and NaHCO3, which could provide the base for scaling-up the CPW treatment technology. Based on the measured quantity change of the CO2 gas generated from the reaction between H2SO4 and NaHCO3 with time under specified initial reaction conditions, the reaction orders with respect to H2SO4 and NaHCO3 were determined. Experiments were also conducted within the temperature of 15-30 degrees C to find various global rate coefficients of the reaction to calculate the activation energy and the pre-exponential factor of the empirical Arrhenius form of the bicarbonate removal reaction, which are 197.7 kJ/mol and 3.13 x 10(34) (mol(-3.7) x L(3.7) x sec(-1)), respectively.

Coal is a potential source of naphthenic acids in groundwater

Naphthenic acids, with the general formula C(n)H(2n+Z)O(2), are found in conventional petroleums and oil sands ores. These acids are toxic to aquatic life, so their discharge from petroleum processing into receiving waters must be avoided. In a previous study, naphthenic acids were putatively identified in groundwaters from two domestic wells that were distant from petroleum sources. However, coal deposits were near these wells. In this study, waters from the two wells were extracted and analyzed by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry to unequivocally confirm the presence of naphthenic acids and other organic acids. In addition, distilled water was percolated through three crushed coal samples and the leachates were shown to contain a variety of organic acids, including naphthenic acids. These results clearly demonstrate that coal is a source of naphthenic acids and that the naphthenic acids can leach into groundwaters. Thus, the presence of naphthenic acids in waters cannot be solely attributed to petroleum or petroleum industry activities.