Combined Sewer Long Term Plan

Download the "Student's Guide To Understanding Combined Sewer Overflows" (PDF)

Download the "Muncie Wastewater Treatment Facility" handbook for students (PDF)

Download info on the Combined Sewer Overflow Long Term Control Plan Citizens Advisory Committee Recommendations (PDF)

Download the Combined Sewer Overflow and Flood Stations Map of the city of Muncie. (PDF)

The Water Pollution Control Act passed by Congress in 1972 contained a wide range of requirements aimed at eliminating pollution of our streams and rivers. For many years, EPA and the Indiana Department of Environmental Management (IDEM) have concentrated on upgrading wastewater treatment plants. The focus now is concentrated on reducing and eliminating, if possible, pollution caused by overflows from combined sewers (CSO's).

Combined Sewer Overflows (CSO's) - A combined sewer conveys both sanitary waste and storm water through a single pipe system to a wastewater treatment facility. During heavy rainfall events, the flow in the combined sewer system exceeds the capacity of the wastewater treatment plant. To prevent overloading the wastewater treatment plant, a number of overflow points have been constructed on the combined system throughout Muncie. Muncie has 25 overflow points or CSO's located along the river. Collectively, the sewer collection system and treatment plant are known as Publicly Owned Treatment Works (POTW). CSO discharges are point sources of pollution subject to the National Pollution Discharge Elimination System (NPDES) permit which means that Muncie is responsible for any polluted matter entering the river from the 25 CSO's.

Water Quality Impacts From CSO's - The greatest impacts of discharges from CSO's are associated with bacteria in the untreated sewage. The maximum concentration of bacteria allowed in Indiana waters is 235 colonies E. coli/100 ml. of water, and will likely be exceeded with any CSO discharge. Other sources of pollutants discharged from CSO's which have water quality impacts include industrial discharges to the sewer system, pollutants from urban storm water runoff, the dumping of automotive fluids and household chemicals down storm sewers and carelessly discarded litter. Under normal dry weather conditions, these materials will likely be transported to the treatment plant where they will be removed or treated. However, during heavy precipitation events, these same materials will most likely find their way to waters of the State.

Long Term Control Plan (LTCP) - Under the terms and conditions of the NPDES discharge permit for the wastewater treatment plant, Muncie must submit a CSO Long Term Control Plan to IDEM by November 2001. The Department of Environmental Management for the state of Indiana prepared a CSO strategy of plan in 1996 to serve as a guide for all CSO communities. The 1996 Indiana CSO Strategy is broken into two phases:

Phase I focuses on the technology-based methods (referred to as the "nine minimum controls") that maximize the existing infrastructure.

Phase II will generally require capital expenditures to meet water quality standards if Phase I proves to be inadequate. The implementation of Phase II CSO controls may be done in a phased manner over several five-year permit cycles.

The "Nine Minimum Controls"

1. Proper operation and regular maintenance of the collection system - MSD is utilizing street sweeping, cleaning catch basins and siphons, and continually working on small projects (separating combined sewers) in the District to accomplish this goal.
2. Maximum use of the collection system for storage of excess flows. At this point the collection system has very few places for storage during a high flow event.
3. Review and modification of Industrial Wastewater Pretreatment Programs. The District is very fortunate to have the Bureau of Water Quality working with industries to continually bring them under compliance.
4. Maximum use of flow to the POTW for treament. The Muncie Water Pollution Control Facility is undergoing construction to be finished in the year 2002 to effectively treat flow up to 30 MGD.
5. Prohibition of CSO discharges during dry weather. MSD is working on this through LTCP.
6. Control of solid and floatable materials in CSO discharges. MSD is considering incorporating movable weirs with automatic operators for the purpose of keeping the floatables from the CSO overflow.
7. Pollution prevention programs (source control and source reduction). MSD already has in place street sweeping, catch basin and siphon cleaning and Tox-a-way Days.
8. Public notification to ensure that the public receives adequate notification of CSO occurrences and CSO impacts. MSD will be putting signs at CSO's, using the website to explain CSO's, and creating a video for public information in the future.
9. Monitoring to characterize CSO impacts, identify problem CSO points, and identify the effectiveness of the previous 8 controls. The ninth minimum control is implemented through the Stream Characterization and Evaluation Protocol and Report (SRCER). The Bureau of Water Quality, MSD's Engineering and HNTB have put together this information using a modeling program, samples, etc.

Indiana Senate Enrolled Act (SEA) 431

Because of the enormous expense associated with complete elimination of all CSO discharges, the Indiana legislative body passed SEA 431 during the 2000 session:

SEA 431 grants a temporary suspension of water quality limits during wet weather events providing the community requesting such suspension has an approved Long Term CSO Control Plan in effect. Without an approved Long Term Control Plan, a community is legally in violation of their NPDES permit each time a CSO overflows and therefore subject to enforcement and fines by IDEM and EPA. SEA 431 requires CSO communities to (1) capture the first flush for treatment, and (2) implement cost-effective controls that will attain water quality standards (or maximize the extent to which they are attained if a Use Attainability Analysis (UAA) demonstrates the designated use is not attainable.)

SEA 431 and federal law also require a CSO community to apply for a temporary suspension to implement CSO controls until they reach the point where implementation of further controls would result in substantial and widespread economic and social hardship. In addition to conducting a Use Attainability Analysis, CSO communities must conduct a knee-of-the-curve" analysis. The knee-of-the-curve analysis consists of estimating the CSO control costs for a range of control levels and rainfall events. The curve is developed comparing cost to benefit and identifying the point on the curve where additional costs do not result in significant benefits.

Public Input and Participation
Establishing an maintaining public input and participation is an essential part of the Long Term Control Plan development. During development of the Long Term Control Plan, the Sanitary District will issue progress reports to the news media as well as on the Sanitary District website and at regular Sanitary District Board meetings. A citizens Advisory Committee will be established to provide the opportunity for public input.