Recycling Treated Municipal Wastewater for Industrial Water Use

TM3: Recycled Wastewater System Components and Costs
Recycling Treated Municipal Wastewater for Industrial Water Use
3.4 Selection of Water Reuse Treatment Technologies for
Specific Industrial Water Uses
3.4.1 Factors to Consider
There are a host of factors to consider in selecting a treatment process train for water
reuse applications. The main factors have been discussed in this document and were
used to define the base level water quality and base WWTP processes, including:
Water reuse quality goals
Effluent wastewater characteristics
Type of water reuse application (purpose of water supply)
The other factors to consider for specific applications are those typical of any planning
study:
Integration with existing facility processes, hydraulics, and site conditions
Future facility or other service area expansions and proximity and treatment
requirements for water reuse applications
Process flexibility (for new and existing processes)
Environmental issues
Operation and maintenance (O&M) requirements including energy, chemicals,
labor, automation, laboratory, and general maintenance.
3.4.2 Technologies by Target Constituents
Section 3.2.1 presented the treatment processes typically used to produce different
levels of quality for water reuse applications. Table 7 lists these processes and
identifies the specific categories of constituents they remove. The base WWTP defined
for this study removes suspended solids, dissolved organic matter, ammonianitrogen,
phosphorus, and pathogens (advanced secondary treatment). This supply
may be adequate for some industries without additional treatment.
The next level of treatment is usually filtration for consistent disinfection practices
and/or additional particulate removal. Filtration is required by Title 22 for water used
in cooling towers, or other applications with the potential for human contact.
Particulate matter includes: suspended solids, colloidal, and/or organic matter and
the related phosphorus (cell content). Filtration reduces particulates, including
pathogens (bacteria, protozoan cysts, and oocysts), and also improves the disinfection
process by removing particles that shield pathogens from the disinfectant (chlorine,
UV, ozone).
The next level of treatment will typically require some degree of dissolved constituent
removal or additional nutrient removal. Hardness, related salts, metals, silica, and
color were some of the constituents identified in Table 2 that required limited
concentrations for various industrial uses. The treatment technology selected will
depend on the exact constituents and amount to be removed, as well as the other
processes used for the main WWTP and reclamation-specific processes.
22 Craddock Consulting Engineers
In Association with CDM & James Crook
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