The majority of spills continue to be grease, roots and debris. Other common factors associated with spills are broken or sagging pipes and wet weather.
ENV conducts a preventive maintenance (PM) program implementing various facets to address both grease and roots in the city’s sewer lines. X70 SSAW Line Pipe
ENV’s Collection System Maintenance utilizes high-pressure Vactor trucks to flush grease from sewer lines, while addressing roots by mechanical and chemical approaches. Crews insert rods with sharp cutters into the ends of affected pipes to cut away intruding roots. After this process is completed, crews shoot a foam poison through the pipes to deter roots from growing for the next six to 12 months.
Smoke testing, which blows non-toxic smoke into sewer lines, records where it appears through broken pipes and other illegal connections. Additionally, the Environmental Quality’s Regulatory Control Branch of ENV addresses commercial grease in cleanouts and other paths on private properties. These areas allow rainwater inflow and infiltration to enter and overwhelm the sewer system causing spills.
Additionally, the Environmental Quality’s Regulatory Control Branch of ENV addresses commercial grease from restaurants and residential grease through its FOG (fats, oil, grease) program, which includes inspections, investigation of problem areas, follow-up warnings and enforcement actions, along with outreach and educational programs.
ENV is working with communities, one-by-one around the island, to keep residential runoff out of the sewers. Smoke testing looks for leaky pipes and other places where rainwater may be entering City sewer lines.
Where smoke comes out, water can come into the sewer system.
Of the 7500+ private properties tested so far, about seven percent have leaks, faulty pipes, missing cleanout caps or illegal connections to sewer lines. The good news is that a majority of the problems identified are easy and inexpensive to fix. A cleanout cap, the most common culprit, costs about $7 and is sold at most hardware stores.
While this may not seem like much, the amount of excess water coming into the system adds up. Studies show, about half of the water processed at treatment plants comes from residential properties.
ENV is determined to identify properties island-wide that have inflow problems and to notify owners of the action required to resolve the problems. ENV workers first test areas most prone to wet weather flooding. Residents get a letter from the City in the mail two weeks before the smoke testing begins, and a door hanger on homes a week before the testing.
A smoke machine pumps a non-toxic liquid smoke into a manhole on the street. The smoke runs along the city sewer line to the centipede-like legs of private plumbing lines. If all is well, smoke will spiral out of small vents on house roofs. Smoke coming from a rain gutter or downspout is a sign that the gutters are draining into the sewer system instead of the storm drain or onto the grass. Smoke that pours out of the cleanout pipe in the yard may indicate a broken or missing cap.
Maintenance crews armed with cameras take photos and document the results. Finally, homeowners are notified by mail if their plumbing has leaks.
Down spouts, yard drains and cleanout caps are easy and inexpensive to fix and must be promptly corrected by the property owner. Scheduling to correct the more costly problems may be negotiated with the city. If the problem is underground on private property, homeowners may have to pay to replace the pipes. Ongoing noncompliance may eventually result in fines.
ENV smoke testing crews find that people are usually pleased to learn something about their sewer system and amazed to learn that about half of the extra water entering the system during heavy rains comes from residential property. Once homeowners understand what we are doing, the reaction is very positive.
National studies estimate that private property sources account for 50% of the unwanted water in the system. Previous tests conducted on Oahu have been consistent with these results.
Reducing and preventing collection system spills to the maximum extent possible is the city’s goal. It is also one of the requirements of the 1995 Consent Decree between the city, state Department of Health and the U.S. Environmental Protection Agency.
Without a concerted effort on the part of all residents to control storm water overflow, the only alternative is to increase the capacity of the wastewater treatment plant or construct larger lines and storage tanks – an extremely costly solution.
During heavy rains, half of the extra water entering the sewer system comes from private property. Excess water in the collection system leads directly to sewage spills.
Here’s how you can help:
Drain rain gutters into a storm drain or directly onto the grass. Remove yard drains and cap the sewer pipe with a cleanout cap.
DO NOT REMOVE cleanout caps during heavy rains, allowing water, rats or other objects to enter the collection system.
Watch for tree roots penetrating the lateral in your yard or driveway.
Discharging storm water into the sewer system violates a City Sewer Ordinance. A fine may be assessed.
Residential sewer lines are the responsibility of the homeowner. Sewer mains and manhole problems are the responsibility of the City.
During heavy rains, half of the extra water entering the sewer system comes from private property. Excess water in the collection system leads directly to sewage spills.
Here’s how you can help:
Drain rain gutters into a storm drain or directly onto the grass. Remove yard drains and cap the sewer pipe with a cleanout cap.
DO NOT REMOVE cleanout caps during heavy rains, allowing water, rats or other objects to enter the collection system.
Watch for tree roots penetrating the lateral in your yard or driveway.
Discharging storm water into the sewer system violates a City Sewer Ordinance. A fine may be assessed.
Residential sewer lines are the responsibility of the homeowner. Sewer mains and manhole problems are the responsibility of the City.
On Oahu, as in other developed coastal and island areas around the world, heavy rains and spills go hand-in-hand.
ENV crews are well-trained, well-equipped and highly motivated. They are part of our community and care about it, as you do.
Whatever the cause—heavy rains, a ruptured pipe, old or malfunctioning equipment, the protocol is generally the same.
Warning signs are posted immediately at potentially affected beaches and streams to alert people to keep out of near shore waters. We collect water samples and test for harmful bacteria. We bring in 3,000-gallon capacity pump trucks to suck up the spills on land. Other team members find the problem and fix it, then help homeowners deal with problems on private property.
After a spill, lab specialists continue collecting samples for testing until Oahu’s oceans and streams are cleared. We process the results within 24 hours and deliver them to the state Department of Health (DOH) for review. Warning signs remain until we are certain water quality is safe. (Sadly, warning signs are often stolen as quickly as they are put up). DOH decides when the waters meet state and federal clean water requirements and are safe for recreation.
Wastewater spills are bound to occur in a heavily populated island community such as Oahu. The wastewater system is constantly being repaired and upgraded to reduce the frequency and severity of spills.
Roger Babcock, Jr. Ph.DPE, Director (Poʻo) Michael O'Keefe Deputy Director (Hope Poʻo)
1000 Ulu'ohi'a Street, Suite 308 Kapolei, HI 96707 (808) 768-3200 (Refuse Questions) (808) 768-3486 (808) 768-3487
Gas Lines Copyright © 2024 Department of Environmental Services