SSOs and CSOs What are they and what are we doing about them?

Don Kennedy – Training Coordinator James LaLiberte – Training Coordinator Combined sewers were introduced to the larger American cities in the mid-19th century.

They were designed to dry out streets by collecting rainwater runoff, domestic from newly invented flush toilets, and industrial wastewaters all in the same . In dry weather, a system sends a town’s entire volume of wastewater to a treatment plant, which treats and discharges to a waterway.

The problems, generally, arise during heavy or extended events which can overload the system and seek relief. Such events can result in either a Overflow (SSO), a Combined Sewer Overflow (CSO), or both.

While both situations act as a relief for the system, one is intentional and the other is not. An SSO is an unintentional discharge of wastewater to the environment or personal property. SSOs are, generally, the result of poor sewer management and maintenance.

Flow through sewer lines can be restricted by fats, oils and greases (FOG) or by tree roots. The system then does not have the capacity to handle a significant rain event, resulting in wastewater escaping through , residences or businesses.

TREE ROOTS IN SEWER Other contributors to the system are Inflow and . These situations allow to enter the sewer system which shouldn’t. Infiltration - through bad joint or cracked pipes. Inflow – through illegal or unapproved connections, such as roof gutters, yard drains or sump pumps. Sanitary Sewer Overflows TYPES OF SEWERS • SANITARY SEWER • WASTEWATER ONLY

• STORM SEWER • STORM AND SURFACE WATERS

• COMBINED SEWER • INCLUDES MIXTURES OF WASTEWATER, STORM, AND SURFACE WATERS TYPES OF OVERFLOWS

DRY-WEATHER OVERFLOWS CAUSED BY SYSTEM MAINTENANCE PROBLEMS OFTEN IN CONJUNCTION WITH STRUCTURAL ISSUES

WET-WEATHER OVERFLOWS CAUSED BY CAPACITY PROBLEMS OFTEN AFFECTED BY MAINTENANCE OR STRUCTURAL PROBLEMS AGING INFRASTRUCTURE SPRINGFIELD MA

PORTLAND ME WHY DO SEWERS OVERFLOW? INAPPROPRIATE MATERIALS:

FOG TREE ROOTS FAULTY PIPE CONNECTIONS ILLEGAL CONNECTIONS AND I&I INADEQUATE SEWER MAINTENANCE UNDERSIZE SEWERS, PUMPS OR EQUIPMENT FAILURES INFLOW & INFILTRATION

WHAT CAUSES SSOs? Main Causes of a Sanitary Sewer Overflow

50%

45%

40%

35%

30%

25%

20%

15%

10%

5%

0% Inadequate base flow Power Failures Pipe Breaks Excessive infiltration and Pipe blockages capacity inflow MITIGATING CSOs

• SEWER SEPARATION

• INLINE STORAGE

• OFFLINE STORAGE

• SATELLITE TREATMENT FACILITIES CAPACITY ASSURANCE, MANAGEMENT, OPERATION & MAINTENANCE (CMOM)

•The sewer utility business is a “fee for service” business.

•CMOM is a framework of business practices for running a utility like a business CAPACITY ASSURANCE, MANAGEMENT, OPERATION & MAINTENANCE (CMOM)

•CMOM is a pre-requisite for keeping a utility in regulatory compliance

•CMOM is paid for by customers who use and also own a portion of the system CMOM COMPONENTS • SEWER USE • CMMS ORDINANCE • FOG CONTROL • CONDITION • I & I PROGRAMS ASSESSMENT (PIPES, • REGULATORY MANHOLES, PUMP PROGRAMS STATIONS) • MAPPING AND GIS CMOM COMPONENTS

• Sewer Overflow Response Plan • Pump station and pipeline PM • O & M SOPs • Readiness review/business practice evaluation • Root control programs • Staff utilization CRITICALITY OF SEWERS •THREE CATEGORIES… • Category A Cost of failure high impact on public health and surrounding environment. Post failure rehab many times cost of planned replacement. CRITICALITY OF SEWERS

• Category B Less critical, preventive action still cost-effective

• Category C Non-critical and minimal effect on surrounding environment MA COLLECTION REGULATIONS

NOTIFY MADEP ABOUT UNANTICIPATED BYPASSES WITH IN 24 HRS

WRITTEN NOTIFICATION WITHIN 5 DAYS

I & I STUDY BY DEC 31ST

DAILY INSPECTION OF PUMP STATIONS > 100K GPD

NEW SEWER CONNECTIONS REQUIRE A 4 TO 1 REMOVAL OF I&I BWSC SANITARY SEWER OVERFLOW EMERGENCY RESPONSE PLAN (SSOERP) STANDARDIZED SET OF ACTIONS FOR SSOS INVENTORY OF TYPES OF SEWERS AND COLLECTION SYSTEM COMPONENTS COMMISSION DEPARTMENT RESPONSIBILITIES FOR SSO MITIGATION NOTIFICATION PROCEDURES: MA DEP USEPA PUBLIC NOTIFICATION SMOKE TESTING

NEIWPCC TRAINING WATERBURY VT WHO IS NEWEA AND WHAT IS VOLUNTARY CERTIFICATION?

Updated: September 2016 VOLUNTARY CERTIFICATION PROGRAM OPERATION AND MAINTENANCE OF COLLECTION SYSTEMS • TYPICALLY A TWO-AND-A-HALF DAY COURSE (VARIOUS TRAINERS) • PARTICIPANTS WILL RECEIVE INSTRUCTION IN ALL ASPECTS OF COLLECTION SYSTEM OPERATION AND MAINTENANCE: • INFILTRATION & INFLOW • ILLICIT CONNECTIONS • MAINTENANCE & REPAIRS • PUMP STATIONS • CMOM & REGULATIONS

• PREPARES APPLICANTS FOR THE OPTIONAL NEWEA VOLUNTARY OPERATION AND MAINTENANCE OF COLLECTION SYSTEMS EXAM VOLUNTARY CERTIFICATION PROGRAM

LABORATORY PROCEDURES • TYPICALLY A ONE-AND-A-HALF DAY COURSE (VARIOUS TRAINERS) • PROVIDES WWTP PERSONNEL WITH THE OPPORTUNITY TO LEARN LABORATORY TESTS FOR NPDES PERMITTING AND PLANT OPERATIONS • TOPICS TO BE COVERED RANGE FROM PROPER SAMPLING TECHNIQUES & ANALYSES TO LAB MANAGEMENT • PREPARES PARTICIPANTS FOR THE OPTIONAL NEWEA VOLUNTARY LABORATORY ANALYST CERTIFICATION EXAM Combined Sewer Overflows CSOs are intentional discharges of wastewater to the receiving waters.

Their purpose is to protect the wastewater treatment process. Treatment of sanitary waste is largely a biological process.

That means the work is being done by trillions of microorganisms. Municipal wastewater treatment plants are designed to handle a broad range of flow rates. Proper operating conditions can be maintained by having more or less equipment online at any particular time. There are limits, however! During heavy , flow to the treatment plant can easily be double, triple, or more of the average flow. This means the velocity through the plant increases accordingly. In these situations, a plant can experience a “wash- out”. Loss of organisms; loss of treatment. CSOs are designed to avoid that situation. CSOs

The collection system is constructed such that all flow is directed to the treatment plant, up to a certain point.

When flows exceed that point, excess flow is allowed to discharge to the receiving stream in order to protect the treatment plant and prevent backup into streets and buildings. The resulting CSO dumps raw sewage into lakes, rivers and coastal waters, potentially harming public health and the environment. COMBINED SEWER OVERFLOW So, what is being done about this???? While CSOs are a necessary safety valve for the system, much work is being done to mitigate the effect of discharging raw sewage to receiving waters. The ideal remedy is to separate sanitary sewers and storm sewers. Like all remedies, this is costly and extremely disruptive. Boston’s MWRA receives wastewater from over 5100 miles of sewer into their 227 miles of sewer. “Bypassing” or “Blending” – during peak flows, the utility is allowed to route a portion of the flow around the biological process, then combine these flows with the treated portion. After blending, the effluent is disinfected prior to discharge. ACTIVATED SLUDGE PROCESS DISINFECTION

BIOLOGICAL DISINFECTION REACTOR SEC. INFLUENT CLARIFIER EFFLUENT AIR OR OXYGEN

RETURN ACTIVATED SLUDGE

WASTE ACTIVATED SLUDGE Another remedy is to construct storage facilities to hold the excess stormwater until the event subsides, then bring it back into the system at a controlled rate.

Large tanks or tunnels, holding upward of a billion gallons must be constructed to hold the water. These come at great costs. Providence, RI - $470 MM Boston, MA - $225MM 1,000,000,000 Gallons 7.1 miles long Lastly, some CSOs are using basic treatment, such as screening and disinfection to reduce the impact of the CSO discharge. 34 of 84 closed by 2015

Green infrastructure is a cost-effective, resilient approach to managing wet weather impact.

Green infrastructure reduces and treats Stormwater at its source while delivering environmental, social and economic benefits. Green Infrastructure

Downspout disconnection Rainwater harvesting

Rain gardens

Bioswales Permeable pavements

Green roofs