초록 ▼

This invention discloses a cost-effective process for separating contaminants and a wide-range of fouling material from surface water, ground water and from industrial effluents. Having undergone effective pre-treatment, the water can be purified further by using high-surface area spirally wound mic

This invention discloses a cost-effective process for separating contaminants and a wide-range of fouling material from surface water, ground water and from industrial effluents. Having undergone effective pre-treatment, the water can be purified further by using high-surface area spirally wound micro-filtration (MF), ultra-filtration (UF), nano-filtration (NF) or reverse osmosis (RO) membranes. High-quality potable water free from pathogen and other contaminants is thus produced at low-cost from the pre-treated surface water and ground-water. Conversely, pre-treated industrial effluents are further purified at a relatively low-cost using NF or RO membranes, thus producing water suitable for recycle or surface discharge. The process of this invention uses cationic inorganic and/or polymeric flocculants to coagulate and flocculate the water-borne colloidal matter (e.g. clays, iron hydroxides, naturally occurring matter (NOM's), etc.), followed by filtration using a multi-media filter, charge neutralization and reversal and final filtration using a 5-micron cartridge filter. These pre-treatment steps provides a good quality water having a low Silt Density Index and a significant negative zeta potential, thereby ensuring against irreversible chemical fouling of the spirally-wound membranes.

대표청구항 ▼

1. A membrane process for the economical treatment and purification of surface water containing colloidal suspended solids, natural organic matter (NOM) and biological contaminants which separates contaminants and produces safe drinking water while eliminating irreversible chemical fouling of the me

1. A membrane process for the economical treatment and purification of surface water containing colloidal suspended solids, natural organic matter (NOM) and biological contaminants which separates contaminants and produces safe drinking water while eliminating irreversible chemical fouling of the membrane surface, comprising:a) Adding a multi-valent metal coagulant and a cationic flocculant and mixing the chemicals in said surface water to form a stable floc containing all the colloidal suspended solids, natural organic matter (NOM) and biological contaminants; b) Filtration of said surface water to separate the flocculated solids using a multi-media filter (MMF) bed providing pre-filtered water which contains a slight excess of the flocculating cationic flocculant which comprises a polymer and a positive charge associated with the polymer and residual unfiltered particles; c) Neutralization and reversal of the excess positive charge in said pre-filtered water to produce a slightly negatively charged pre-filtered water; d) Fine Filtration of said slightly negatively charged pre-filtered water using a filter selected from a group consisting of woven fabric depth filters, bag filters membrane cartridge filters and combinations thereof and having a nominal pore size equal to or less than 5 .mu.m, producing pre-treated water having a Silt Density Index (SDI)<5; e) Pressurizing and introducing said pre-treated water into the high pressure side of a membrane system to produce a purified membrane permeate as drinking water on the low pressure side of said membrane system which is free from colloidal and microbial contaminants and a membrane concentrate on the high pressure side of said membrane system which contains all residual contaminants and to discharge said membrane concentrate safely to receiving waters or to sanitary sewers; and f) Disinfection of said drinking water before distribution.