|
Mercury
Work Group
Phase I Reports >> End of Pipe Report
Executive Summary | End-of-Pipe Report |
Operations Report | Infrastructure Report
For more information,
contact David Eppstein by email at
deppstein@masco.harvard.edu,
or by calling 617-632-2860.
Findings
The Subcommittee has learned that not one of the technologies
presented is individually or collectively capable of reducing
the concentration of mercury in a facility's discharge to below
1.0 part per billion on a consistent or sustainable basis. Some
of the technologies have demonstrated abilities in removing 99.7%
of the total mercury from the wastestream prior to discharge but
the pretreated effluent still has a mercury content at the 3 to
5 ppb level. Most of the technologies should be viewed as polishing
systems only and, as a result, initial pretreatment is required
before these advanced techniques can be applied; all of which
requires a serious amount of space and money to be installed.
We have also learned, that there are many characteristics of our
particular wastestreams that, if not controlled, can significantly
and adversely impact some of the technologies that have been investigated.
For example, chlorine bleach, used as a hospital disinfectant,
can cause a rapid deterioration of the membranes used in nanofiltration
and reverse osmosis based systems. Oil and grease can cause an
almost immediate failure of ion exchange media. The organic material
and biological activity present in the raw wastewater will use
activated carbon as a food source, in turn, causing premature
failure of that media.
The smaller systems which are capable of handling a few hundred
gallons per day have associated capital costs which range from
$10,000 to $20,000 on up. Those systems which are not initially
capital intensive do have much higher annual operating costs.
Larger institutions with higher flows will be faced with a corresponding
higher though not directly proportional costs. For example, one
installation treating about 2,000 gallons of wastewater per day
spent only $100,000 to install a system but continues to
incur operating costs at the rate of $150,000 to $200,000 per
year for media replacement alone. The system, however, does not
produce an effluent which meets the stipulated limit of 1.0 ppb
on a continuing basis. We have also seen systems, in place, which
are reported to have cost in excess of $2,000,000 to install and
are required to be maintained by a minimum staff of eight (8)
Massachusetts certified/licensed operators. Though not designed
or operated specifically for mercury removal, this system provided
us with a perspective on the size and complexity of a facility
necessary for handling more than 100,000 gallons per day of wastewater
which is typical of some of our larger member facilities. This
system occupies approximately 10,000 square feet of floor space
and has an annual operating budget of $1,000,000.
In an attempt to place some perspective on these costs as a function
of our membership's relative size according to flowrate, the Subcommittee
has developed the following "Order of Magnitude" table
of costs which should be anticipated by an Institution when deciding
whether to make an investment in an End of Pipe solution which,
according to our research, cannot meet a stipulated effluent discharge
standard of 1.0 ppb:
| Rank |
Flowrate, gdp |
Capital Cost, $ |
Operating Cost,
Expressed as a % of
Capital/yr |
| Large |
> 20,000 |
1 to 2 Millions |
50 % |
| Medium |
5,000 to 10,000 |
Hundreds of Thousands |
100 % |
| Small |
< 1,000 |
Tens of Thousands |
200 % |
RETURN TO END OF PIPE
REPORT
TABLE OF CONTENTS
|
