Physico-chemical and cementitious properties of sludge from oil field effluent treatment plant

Sludge generated in the effluent treatment plants (ETPs) of oil fields cont ain calcite, clay and other inorganic materials as well as hydrocarbon oil. The amount of the latter is often more than the permissible level for safe disposal by landfilling. The thermoanalytical characteristics of the sludg e generated in the ETP of Lakwa oil field, Assam, India were investigated b y using TG, DTG, DTA, XRD, FTIR techniques and chemical methods. The lime r eactivities of the sludge ash and the physical properties of blended cement containing the ash were evaluated. Decomposition of calcite starts from ab ove 550 degreesC and it is succeeded by several solid state reactions invol ving CaO and aluminosilicates forming now phases. Gehlenite (Ca2Al2SiO7) ha s been identified as one of the products and it forms above 750 degreesC. S ludge ash prepared at 750 degreesC consumes considerable amount of lime but it is not suitable for preparation of blended cement. (C) 2001 Elsevier Sc ience Ltd. All rights reserved.