Regardless whether it is from home or industry use, all water from showers, sinks, toilets, laundry and commercial waste winds up flushed. This water is then distributed to wastewater treatment plants across the country. Sewage refers to the wastewater and excrement that travels through a building's pipe system until it reaches the local sewer system for treatment.
The EPA estimates that the average American family can create more than 300 gallons of wastewater per day just from home use. Expanding to industrial uses, the amount of water used daily drastically increases. In order to manage these mass amounts of water properly, sewer systems must be prepared.
Sewer systems are a network of underground pipes for wastewater to travel through. When water is flushed out of a house or business, the sewer pipes beneath roads and lawns carry this waste to a treatment facility.
Three main types of sewer systems often shape sewer inspection:
- Sanitary: Simply referred to as sewers, sanitary sewers carry wastewater from homes and businesses to wastewater treatment plants.
- Storm: Also known as surface water systems, storm sewers channel rainwater and snowmelt into rivers, streams and other bodies of water. Learn more about Storm Systems here.
- Combined: A combined sewer system uses a single pipe to carry both wastewater and surface water to a wastewater treatment plant.
In modern practice, separate sanitary sewers and stormwater lines have replaced most combined systems. In wet climates, increased runoff water combined with the wastewater from buildings causes combined sewers to overflow. Any time this happens, there is a risk of raw sewage spilling directly into public spaces. This puts any of the surrounding natural water supplies at risk of contamination.
With the use of separate sanitary and storm sewers, there is less risk of environmental damage. By separating the two water levels, wastewater can safely travel to a treatment facility with much lower risk of flooding during inclement weather. If a separate stormwater line were to overflow during severe rainfall, there would be no risk of external contamination due to the neutrality of the water.
There are often pipes adjacent to stormwater lines in separate sanitary sewer systems. These pipes handle wastewater flushed from industrial sites, showers, sinks, toilets and laundry. Water enters the sewer system via relatively small pipes, typically 2-6”. These pipes transfer residential and commercial waste away from the building towards septic systems or the sewer main.
Sewage travels through urban wastewater systems to various headworks that screen out debris. Though most wastewater can flow by gravity, sewer systems may require pumping stations for low-lying areas. Once at the treatment facility, the sewage goes through a series of stages before the facility recycles it back into the water network.
There are three core stages that treatment facilities go through to remove impurities from the wastewater:
- Primary treatment: Up to 60% of suspended solids are removed from the raw sewage as it passes through the primary settling tanks. Screening traps human waste and other solid objects while aeration helps push solids to the bottom for effective removal. However, only removing larger imperfections will still leave the treated wastewater with many toxic compounds.
- Secondary treatment: The goal of the secondary treatment is to remove the dissolved organic matter that remains after aeration and screening. This process adds microbes to the water to consume the organic matter and convert it to carbon dioxide, water and energy. This secondary treatment removes about 85% of the waste and most toxic chemicals from the water.
- Tertiary treatment: In tertiary treatment, the goal is to remove all remaining bacteria. Depending on the technology and the level of technical expertise available at the facility, this final stage of treatment may vary. Common tactics include a combination of ultraviolet radiation treatment, chlorine disinfection and additional microbe infusion. When done correctly, this stage of treatment can remove over 99% of all impurities from sewage.
The structures that make up the sewer network, the sewer pipes, manholes, pumps, and tanks, are mostly underground. Buried underground, it is difficult to determine which structures are in good shape and which are not. It would not be possible due to cost, labor, or logistics to replace all pipes at once. Repairs need to be prioritized based on pipe conditions to avoid the potential for a collapse. In order to accurately determine structural integrities, a thorough inspection must be conducted. Pipes need to have their condition verified, preferably following NASSCO compliant PACP code, to properly delegate repair timelines.
It is essential to monitor and maintain the sewer system's structures to prevent leakage or breaks in the pipes. If wastewater is discharged back into our environment, there can be dire consequences for the health and well-being of both people and wildlife. Routine inspection is the most cost-effective way to maintain pipes, and ensure the protection of communities. Regular inspection also enables municipalities to stay on top of their assets which allows for informed budget forecasting.
Regardless of the inspection method of choice, public sewer mains are entered through utility hole covers. Under routine circumstances, inspections can begin by either manually entering the pipe or deploying a remotely operated vehicle such as a pipe crawler. In some instances, the pipeline will need to be completely or partially excavated for more robust access.
Manual or visual inspections involve inspectors physically entering the pipes. In addition to examining the pipe's interior with a flashlight, the inspector may inspect the conditions surrounding a pipe or other components of the sewer system's infrastructure.
Generally, pipes with diameters less than 48 inches are too small for an inspector to enter. Sanitary sewers tend to have narrower pipes closer to 8 inches in diameter, making the pipes inaccessible for humans. In these situations, inspectors commonly opt for pipe crawlers equipped with CCTV cameras. These crawlers can capture high quality visual data as the vehicle is piloted through the sewer system.
Pipe Trekker manufactures pipe crawlers that can center in pipes from 6-36” in diameter. These portable and fully submersible systems allow inspectors to take a quick look at the pipe's condition without physically entering the sewer. Hybrid power options allow for a full eight hour work day on a single charge, or endless operation via a topside powered reel.
If excavation is the preferred method of inspection for a city, they typically deploy what is called a reactive approach. This is typically only enacted when a major problem, such as a main break, an overflow, or a blockage occurs. At this stage, the damage is done and immediate repairs need to be initiated before the issue continues or escalates.
Need a crawler for your next pipe inspection?
Just like all infrastructure, as sewer systems age, their structural integrity declines. The American Society of Civil Engineers recommends using a defect-based risk assessment model. Cities across the globe have started conducting proactive sewer inspections as part of their regular maintenance. Regular sewer inspections can identify areas of concern within a sewer network and catch major issues before they happen.
Pipe crawlers make any pipeline inspection faster and more efficient. From sewer and sanitation pipes to culverts and storm pipes, crawlers are built for numerous wastewater and stormwater applications. Pipe Trekker offers portable, battery-operated crawlers that are completely submersible using magnetically coupled drives. This means that the wheel assembly has an opposing magnet to the drive assembly. This locks into place as a water tight assembly without the need to pressurize the crawler (otherwise known as “gas” it or fill it with nitrogen) to maintain its waterproof integrity.
The 1080p pan/tilt/zoom camera offers precise visuals which can be illuminated by the attached auxiliary lights. Operators pilot the system via a handheld controller featuring a 7” screen which will instantaneously display the CCTV camera feed at near zero latency. One of the most convenient features of Pipe Trekker’s crawlers is the ability to record video, snap images, and seamlessly build reports via WinCan, POSM, GraniteNet, ITPipes, or CTSpec. Consistently documenting verified reports provides municipalities with reliable data for forecast modeling.
Each year that a sanitation or stormwater pipe goes uninspected can exponentially increase the risk of damage. It's essential to perform routine inspections on sewer systems to ensure our water ends up in the appropriate places. Pipe Trekker's remotely-operated vehicles help municipalities perform fast and efficient sewer inspections with over a decade of proven performance.
Contact Pipe Trekker today for more information about how our innovative, durable, portable pipe crawler solutions can help solve your unique mission.