Case Study - Demonstration Plant of Water Recycling of Treated Industrial Wastewater Using Microfiltration/Reverse Osmosis and Activated Carbon Filter for Process Use in a Petrochemical Plant, Singapore

Case study – Demonstration plant of water recycling of treated industrial wastewater using Microfiltration/Reverse Osmosis and Activated Carbon Filter for process use in a petrochemical plant, Singapore

Membrane processes employing pre-treatment with micro-filtration (MF) with reverse osmosis (RO) have been proven to be reliable and economical in Industrial Water Recycling facilities. This has resulted in the conversion of existing Conventional Activated Sludge (CAS) process for treated industrial wastewater recovery for process use.

The aim of this paper is to demonstrate a phased approach of carrying out technological and economic assessment of an alternative approach of applying membrane technology, for water recycling of treated industrial waste water for process use. It has been installed at downstream of the existing CAS at a wastewater treatment plant in the Singapore Petrochemical Complex.

Due to the variability of industrial effluents, this demonstration plant was developed following a rigorous Phase 1 – Pilot Plant with different configuration of pre-treatment membrane (MF/UF) and material selection with RO. Actual treated wastewater effluent was used for the wide range of investigation, particularly on the susceptibility of membranes fouling and formulation of cleaning solutions for membrane flux recovery. The Phase 2 demonstration plant was then designed and constructed, followed by trial runs with enhanced cleaning regimes for fouling control, to validate critical parameters such as allowable flux for a pressurized pre-treatment membrane units and RO permeate quality. The permeate is then passed through an activated carbon filter, to remove any residual organics and free chlorine as the feed water to ion-exchange pure water process unit to produce boiler feed water (BFW) to generate high pressure steam.

Indeed, with the expected successful implementation of the wastewater recovery system, PCS’s uptake of fresh water can be potentially reduced by about 10% when the recycling plant operates at its full capacity.