Budget Message / Highlights - Metropolitan Water Reclamation ...

METROPOLITAN WATER RECLAMATION DISTRICT OF GREATER CHICAGO
2009 BUDGET
• Contingency and Emergency Response Plans: To develop response plans for unanticipated events such as
inclement weather, spills, and equipment malfunctions.
• Sustainable Management Practices and Operations: To enhance the environment by committing to sustainable,
environmentally acceptable biosolids management practices and operations through an environmental
management system.
• Preventive Maintenance: To prepare and implement a plan for preventive maintenance for equipment used to
manage biosolids and wastewater solids.
• Continual Improvement: To seek continual improvement in all aspects of biosolids management.
• Communications: To provide methods of effective communications with gatekeepers, stakeholders, and
interested citizens on key elements of each environmental management system, including information relative
to system performance.
The District is also committed to:
• Generating and utilizing all biosolids in a responsible manner that complies with all requirements of the
District’s permits and applicable federal, state, and local regulations.
• Providing multiple avenues of utilization of biosolids as the District believes that diversity leads to competition
and subsequently lower costs to the taxpayer.
• Continually maximizing the proportion of biosolids beneficially utilized through land application programs and
the District’s Controlled Solids Distribution Program.
• Instilling public confidence in the District’s biosolids activities through consistent production of a high quality
biosolids product.
• Reducing the area of land committed to the processing and drying of biosolids, thereby reducing the potential
for odors and improving the stewardship of District property.
Nutrient Removal
While the majority of nutrients in the Illinois River come from non-point source agricultural runoff, sewage treatment
plants are identifiable sources and can be statutorily regulated. The potential for nutrient standards being imposed on
sewage treatment plants is a very real possibility, and an area of concern.
Nitrates are less toxic to aquatic life than other nitrogen compounds, but must be reduced in downstream drinking water
for public health reasons. Excessive nitrates affect infants’ circulatory systems resulting in “blue baby syndrome.”
Nitrates and phosphates are linked to fertilizing downstream algal blooms and contribute to the growing 8,500 square
mile “dead zone” in the Gulf of Mexico.
The most common conventional
treatment for phosphorus removal in a
sewage treatment plant involves
precipitating the phosphorus out of
solution using a chemical aid such as
alum or ferric chloride. The precipitate
is removed in the sedimentation process
and ultimately ends up in the biosolids.
Another phosphorus removal
technology involves removal of the
soluble fraction of phosphorus through
a biological process involving a series
of anaerobic and aerobic zones. This
technology does not achieve very low
levels of phosphorus, but can be
effective to produce effluent in the
range of 0.5 – 1 mg/L total phosphorus.
Additional phosphorus removal can be
Hennepin
District WRP effluent flow via the Des Plaines and
Illinois Rivers to the Mississippi River and ultimately
into the Gulf of Mexico.
Lockport
Powerhouse
Marsh
Collateral
Channel
Centennial
Trail Marsh
achieved by filtering the liquid stream to remove the fine particulate fraction of the phosphorus. The combination of
precipitation with filtration can remove phosphorus to very low levels, but is very expensive.
The removal of nitrogen-containing compounds from sewage effluent can be achieved through biological processes.
The process involves a series of anoxic and aerobic zones that cultivate the appropriate bacteria to oxidize ammonia
nitrogen to nitrate (aerobic zone) and reduce nitrate to nitrogen gas (anoxic zone). This nitrogen gas is released to the
3
3