Recycling Treated Municipal Wastewater for Industrial Water Use

Emerging Contaminants of Concern
Section 3: Recycled Wastewater System Components and Costs
Recycling Treated Municipal Wastewater for Industrial Water Use
Several emerging contaminants of concern (ECOC) are under evaluation for recycled wastewater
applications that could affect potable water supplies, such as aquifer recharge. They are likely not an issue
for industrial applications with recycled wastewater because water uses are all non-potable, but are
mentioned because it is a concern for potable water treatment and recycled wastewater practices in
general and could affect future regulations and the direction for best management practices that would
impact the entire recycled wastewater industry. The ECOCs gaining attention in recycled wastewater
practices with direct or indirect aquifer recharge include:
pharmaceutically active chemicals (PhACs)
endocrine disrupting compounds (EDCs)
disinfection by products (DBPs) such as N-nitrosodimethylamine (NDMA)
a host of ground water supply contaminants such as 1,4-dioxane and methyl tertiary-butyl ether
(MTBE)
new and reemerging pathogenic microorganisms such as Legionella pneumophilia, Cryptosporidium,
and Giardia
Several ECOCs occur in trace amounts and are of concern to humans for toxicity to the chemicals with
repeated exposure through consumption of the source water. There are also reemerging microorganisms,
thought to be essentially eliminated, linked to disease outbreaks. ECOCs, such as endocrine disruptors,
are also being evaluated for their environmental impact on aquatic communities. Endocrine disruptors and
several of the ECOCs are of domestic, commercial or industrial origins and can concentrate in a
wastewater system. These compounds are not removed with typical WWTP processes and are discharged
with the effluent. The evaluation of the risks associated with these compounds, whether discharged to
surface water, applied to the land with an irrigation recycled wastewater practice, or to aquifers with
recharge practices is just beginning. With improved laboratory analytical equipment that provides
measurement at much smaller concentrations, and increased monitoring for these compounds, the
technical base of information is growing – ECOCs are expected to be a topic for consideration of all
future water supplies, including recycled wastewater.
3.3 Recycled Wastewater Quality and Treatment Technologies
Overview
The treatment requirements and technologies selected for specific industrial reuse applications are based
on a variety of factors summarized in Table 3.3. With all these variables, the treatment process and
transmission system selected is a site and case-specific one. For the purposes of planning and assessing
the feasibility of recycled wastewater systems, some general assumptions were made to define classes of
treated wastewater to meet various industrial uses. A technology-based approach is used to establish the
treatment system and costs for each class of recycled wastewater.
Table 3.3. Treatment Requirements and Technology Selection Factors
Treatment Requirement Factors:
recycled wastewater regulations
the intended use of the water by the industry
the WWTP effluent quality, which is characterized by the
specific:
— quality of the source water used by a community
— industrial, commercial, and domestic discharges to
the WWTP
— treatment processes used at the WWTP
Technology Selection Factors:
the WWTP’s existing process train
the quantity of wastewater recycled at a given
location (there are more cost-effective
technologies for smaller or larger treatment
systems)
whether treatment is incorporated at the WWTP,
at the industry, or at a satellite facility
if storage is required because additional
treatment may be required
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