Abstract

A study was conducted with the aim of treating and disposing of the effluent of an indigenous rubber company rich in PO₄^3- and NH₄⁺ and also determine the effect of the effluent on soil fertility. The basic method used for the biological treatment was aerobic digestion with glucose and magnesium amendments. Most naturally occurring aerobic heterotrophic bacteria in the rubber effluent were found to be capable of utilizing petroleum hydrocarbons as carbon and energy sources. Prominent among these bacteria were the genera of Micrococcus, Bacillus, Staphylococcus, Aerobacter, Proteus, Corynebacterium, Streptococcus, Aeromonas and Pseudomonas. The possibility of using the effluent as soil supplement was established. Oxidative digestion following amendment with glucose yielded only 53 and 40% reduction in levels of NH₄⁺ and PO₄^3-respectively. Addition of glucose and magnesium ions resulted in 95% reduction for NH₄⁺ and 47% for PO₄^3-, respectively. Our results indicate that rubber effluent can be disposed of (i) by controlled spread to agricultural soils as an fertilizing agent or (ii) by aerobic digestion before release in natural flowing waters.

Key words: Heterotrophic bacteria, rubber effluent, amendment, oxidative digestion.