Feasibility and Implementation Assessment of Zero Liquid Discharge Systems in Petrochemical Facilities in Rivers State

Escalating regulatory pressure on liquid effluent discharge from petrochemical facilities in Rivers State, South South Nigeria, has intensified industry interest in zero liquid discharge technology adoption. This study assesses the technical and economic feasibility of zero liquid discharge implementation at three petrochemical facilities in the Port Harcourt refinery industrial complex, based on current effluent characterisation, available treatment technology options, and Nigerian regulatory requirements. Effluent characterisation was conducted over three months, capturing seasonal variability in wastewater generation rates, chemical oxygen demand, total dissolved solids, hydrocarbon content, and heavy metal loading. Technology option modelling included combinations of biological treatment, membrane bioreactors, nanofiltration, reverse osmosis, mechanical vapour recompression evaporators, and spray dryers. Capital and operating cost estimates were developed using equipment cost correlations adjusted for Nigerian construction and energy cost indices. Technical feasibility analysis confirmed that zero liquid discharge is achievable at all three facilities with existing plot space and utility infrastructure. Capital cost estimates ranged from 4.8 billion to 12.3 billion Naira depending on facility scale and effluent complexity. Operating costs were 3.4 to 6.8 times higher than conventional effluent treatment, primarily driven by electrical energy for evaporation. The study recommends phased zero liquid discharge adoption starting with water recovery to meet cooling tower makeup demands. Keywords: zero liquid discharge, petrochemical, feasibility, Rivers State, wastewater treatment