Recycling Treated Municipal Wastewater for Industrial Water Use

Section 3: Recycled Wastewater System Components and Costs
Recycling Treated Municipal Wastewater for Industrial Water Use
3.5 Costs
Basis and Assumptions
Costs were developed as a cost of service in dollars per 1000 gallons ($/1000 gallons), assuming a 20year
debt service. Cost curves are used to provide the cost of service to supply a range of demands from
0.1 to 30 mgd for a 10-mile range from the WWTP. The financial assumptions and detailed basis of cost
are presented in Appendix II-3.
Costs were estimated for the Base and Tertiary 1 through Tertiary 4 water treatment processes described
previously. The base level quality is defined as a hard water that meets regulatory standards for noncontact
industrial water uses. The “base recycled wastewater system” includes treatment processes and
the transmission system for delivery from the WWTP to the industry. “Alternative recycled wastewater
systems” differ from the base system in the treatment processes used to produce a prescribed set of water
quality goals, presented previously in Table 3.5. The recycled wastewater system costs are based on a
wastewater quality typical of a WWTP with secondary treatment and ammonia and phosphorus removal.
Base Recycled Wastewater System Costs
The cost curves developed for the base system indicate that, for some industries, a recycled wastewater
Figure 3.3 Recycled Wastewater System Cost of Service for
0-5 mgd Capacity Base System
Cost of Service, $/1000 gallon
5.00
4.50
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
$2/1000 gallons - Typical Potable Water Supply Cost
0 1 2 3 4 5
Recycled Wastewater Flow/Demand, mgd
supply system can be cost
competitive with potable water
supplies in Minnesota. This assumes
that an advanced secondary
wastewater treatment plant effluent
water quality is suitable for that
industry, or that the industry already
has a treatment system in place for its
existing supply that can be used or
upgraded for a recycled supply. As
shown in Figure 3.3 and tabulated in
Appendix II-3 (Appendix C), a
reclaimed water system designed for
an annual average flow of less than
0.5 mgd is not expected to be
competitive with most potable water
supplies. As the system capacity
increases above 1 mgd, a 10-mile system shows a comparable potable water supply cost of $2/1000
gallons. For flows greater than 5 mgd,
as shown in Figure 3.4, costs drop to
less than $0.60/1000 gallons, even at a
distance of 10 miles for 30 mgd.
Potable water supplies in the
Minneapolis/St. Paul area range from
$1-$3/1000 gallons and fluctuate
around that cost in other areas of
Minnesota. Some rural water systems
have costs over $5.00/1000 gallon.
The base system provides a water
quality that could possibly be suitable
for a once-through cooling process or
sand and gravel washing. It would also
be sufficient for irrigation of restricted
areas on industrial site grounds. To
Transmission Distance, miles
1
2
3
4
5
10
Figure 3.4. Recycled Wastewater System Cost of Service for
5-30 mgd Capacity Base System
Cost of Service, $/1000 gallon
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
$2/1000 gallons - Typical Potable Water Supply Cost
5 10 15 20 25
Recycled Wastewater Flow/Demand, mgd
Transmission Distance, miles
50 Metropolitan Council Environmental Services
1
2
3
4
5
10
30