石油および環境バイオテクノロジージャーナル

概要

Management of Produced Water from Niger-Delta Oil Fields Using a Local Material

Udeagbara SG, Isehunwa S, Okereke NU2*, Nwanwe O, Oguama I, Kerunwa A

Produced Water (PW) from petroleum reservoirs often contains heavy metals and other contaminants that are harmful to the environment. Most of the commonly used treatment techniques have been reported to be ineffective in reducing some of the contaminants’ concentrations to recommended disposal levels. This study was designed to evaluate the effectiveness of bio-adsorbent (orange peel) for treating PW from Niger Delta oil field. A 2.0 m steel adsorption column (0.4 m internal diameter) having four treatment compartments was designed and constructed using standard procedures. Orange peel was washed thoroughly with distilled water, sun-dried (4 days during harmattan period) and oven-dried at 105±5oC for 3 hours. It was ground into powder, sieved (150 and 300 microns,), and then washed with 0.4mol/L HNO3, filtered and rinsed with distilled water to remove any pigment that might interfere with the result. Sample of PW was obtained from field R in the Niger Delta and analysed for heavy metals using an Atomic Absorption Spectrophotometer (AAS). Sample was treated in adsorption column over 3 hours using 150 micron size of adsorbent. Treatment was repeated with 300 micron size. Treated sample was analysed with AAS and characterized. Adsorptions of heavy metals were evaluated using Langmuir and Freundlich models. Data were analysed using regression and ANOVA at α0.05. Concentrations of lead, nickel, cadmium, copper and Barium in PW from field R reduced by 96.2, 47.2, 78.6, 96.1and 42.1 percent, respectively after four hours of treatment with i50 micron size, and for 300 micron size, the concentrations of the same metals reduced by 3.0, 88.8, 57.1, 11.8 and 18.4 percent respectively. The concentrations of other metals were equally reduced to an acceptable limit. The finer adsorbent was more effective. Langmuir model best described the adsorption of lead with isotherm R2 of 0.97, while Freundlich isotherm described the adsorption of nickel and iron, with isotherms R2 of 0.84 and 0.93 respectively. Produced water from Niger Delta oil field was effectively treated of contaminants using orange peel with 150 micron size gave the best result.