The effects of water reclamation technologies on biological stability of industrial water

A modified Assimilable Organic Carbon (AOC) procedure was adopted in conjun ction with Heterotrophic Plate Count (HPC) method to assess the effect of S ingle Effect Distillation (SED) and Reverse Osmosis (RO) lab-scale systems on the biological stability of industrial water. Industrial water was colle cted from a local Industrial Water Works, pre-treated with alum coagulation and cartridge filtration, before being subjected to advanced water treatme nt. The, results obtained in this study indicated that AOCs in the SED prod uct water were in the range of 70-80 mug acetate-C/L, while those in the RO product water ranged from 30-40 mug acetate-C/L in the 15-min permeate to 55-65 mug acetate-C/L in the 3-hr permeate. The above findings suggested th at product water of both systems were potentially biologically unstable and would likely lead to bacteria regrowth during its distribution and storage . Removal efficiencies of lab-scale RO and SED systems on AOC were as high as 90%, dependent on the concentration of AOC-NOX in the industrial water. The RO system had much higher organic removal efficiencies in terms of AOC and DOC than the SED system. Organics removed from both feed waters were fo und to be concentrated in the brine water and rejected water in SED and RO systems respectively.