Combined Sewer Overflow Management

• Sewer Modeling
• Water Quality Management Plans
• Flow Optimization for Collection System
• CSO Storage and Treatment Facilities
• Sewer System Rehabilitation
• Treatment Plant Modeling
• Wet Weather Pollution Prevention Plans
• Regulatory Compliance
• Value Engineering

What is USEPA Policy?
In 1994, USEPA adopted a national CSO Policy requiring the implementation of best management practices, known as the nine minimum controls, and long-term control plans to comply with water quality standards. The goal is to eliminate dry weather discharges and to cost effectively control wet weather to eliminate use impairments. The most common impacts from CSO discharges are floatable and pathogens. Other impacts include dissolved oxygen in poorly flushed waters and toxics associated with combined sewage. EPA recently released a draft policy on blending of wet weather flows within wastewater treatment plants. This policy will help codify EPA policy to maximize treatment at existing wastewater treatment plants, which encourages the use of underutilized primary treatment capacity.

How Does CSO Policy Affect You?
You must implement the nine minimum controls if you own or operate a combined sewer system. In fact, AMSA recently published a bulletin (RA# 04-06 3-17-04) that EPA is actively conducting municipal audits to verify if the nine minimum controls have been completed. Failure to implement these controls can result in a consent order. If local receiving waters do not achieve state water quality standards, you must develop a long-term plan to eliminate use impairments.

How Can D&B Help?
The key to the development of a cost-effective CSO plan is a basic understanding of your combined sewer collection/treatment system, its impact on local waterways and available CSO control technologies. DBGE’s approach is unique and the result of extensive design and practical operation experience with combined sewer/treatment systems. The highlights of our approach include:

• an informal kickoff meeting;
• Review of relevant State regulations, water quality impairments, prior studies of collection or treatment system, and existing permits or consent orders;
• Evaluation of existing sewer system and wet weather operation of the wastewater treatment plant;
• modeling of collection system and wastewater treatment facility as appropriate; and
• development of a practical cost-effective control plan that will be amenable to future regulatory requirements in this evolving environment.

This approach covers each aspect of your combined sewer system. Owner preferences for specific alternatives are incorporated into alternatives. Regulatory compliance milestones are factored into implementation schedules. The final product will provide cost-effective solutions to help you achieve water quality standards where impacts are due to combined sewer discharges.

For more information on D&B’s Wastewater Management Services, please contact Executive Vice President, Steven A. Fangmann, P.E., at (516) 364-9890 x 3005, or Senior Vice President, Joseph H. Marturano, at (516) 364-9890 x 3008.