Wastewater management is essential to all populated areas. Without a proper sewage system, contaminated water can infect the environment causing harm to animals, plants and humans. Understanding the equipment and methods trenchless technology uses to help ensure a healthy wastewater management system is necessary for proper maintenance.

Why You Should Care About Wastewater Management

Wastewater is defined as any water that requires cleaning after use. It includes water used for bathing, washing dishes or clothing, in toilets or garbage disposals. It also includes rainwater that may have accumulated pollutants.

The goal of wastewater management is to clean water, so that is clean enough for use in cooking, drinking, and bathing. When wastewater is not adequately treated, the water is harmful to the environment, animals, and humans. The contamination impacts include oxygen depletion, harm to fish and other wildlife, and restrictions on water use for human consumption or interaction.

What Methods are Used in Wastewater Management?

Trenchless technology is used in both construction and rehabilitation of wastewater management. A few methods used to rehabilitate and construct new sewers include internal point repair, cured-in-place-pipe, and pipe bursting.

Internal Point Repair

Internal point repair offers a couple of different methods which use slightly different equipment. The first method is the grouting/sealing method. To do this, the workers place a remote packer into the pipe. The workers remotely control the packer as they stay topside. Once the packer is in position, controllers perform an air leak test to verify the leak. If detected, the worker expands the bladders to press the grout into place.

Cured-in-Place Pipe

Like a modified cross-section, cured-in-place pipe (CIPP) uses a liner drawn through the existing pipes. (Read A Look at CIPP and Aging Drinking Water Infrastructure.)

Unlike a modified cross-section liner, the CIPP liner uses a resin which helps to solidify the liner into a new pipeline. The liner does not require manipulation to get it into the line as it is a flexible fabric material. Once dried, the liner solidifies into a new pipeline. Like the modified cross-section, the liner doesn’t require grouting as the line is a tight fit.

Pipe Bursting

Pipe bursting is a method of replacing old wastewater management lines. The bursting head breaks up the old pipeline as a new pipe pulls into place. It is the best way to replace sewage lines, especially for areas that wish to increase the diameter to the pipelines. (Read An Introduction to Pipe Bursting.)

Trenchless Equipment Used in Wastewater Management Construction and Rehabilitation

Each method of construction and rehabilitation of wastewater management utilizes a unique set of equipment. Throughout the years, the material used for wastewater management has improved.

Internal Point Repair

To successfully manage internal point repair projects, workers user robotics. These small robots travel the sewage lines instead of human workers. A controller stays topside to navigate the robot using remote control technology. A tiny camera on the bot transmits images back via Closed-Circuit Television.

Robotic technology has come a long way since its introduction in the late 20th century. Not only can these small machines crawl the pipes looking for obstructions, but they play an essential role in removing obstacles and repairing cracks in areas it is difficult for people to enter. There are different machines to complete various repairs, and a single job may require multiple pieces of equipment to complete.

The obvious benefit of using robots for internal point repair is that there is no disruption of the soil above the pipeline. However, because of the cost of the equipment, it is often the most expensive method of wastewater management rehabilitation available.

Cured-in-Place Pipe

One of the most significant benefits of using CIPP liners is the limited equipment necessary for installation. Workers do not have to uncover the section of pipeline they want to rehabilitate. They also do not need to add a launching or retrieval pit. Instead, they can access the line using the nearest manhole.

As CIPP is a flexible liner, it needs to be pulled or pushed through the line. To draw the line into place, an outer layer is necessary to confine the resin. Unfortunately, the outer layer remains in between the liner and the original pipe, which could restrict the flow through the pipeline. When pushed through the pipe, the inverted fiber liner is attached to the conduit on one end. Water pressure inflates the liner and pushes it into place.

CIPP dates back to the early 1970s. Since that time, liners have improved. While many are still typically made from non-woven fiber, some are woven or fiber-reinforced to give it more reinforcement. The resin is made from vinyl and epoxy to provide higher chemical resistance.

Pipe Bursting

Pipe bursting is a more involved method of rehabilitating and constructing wastewater management pipeline connections. Instead of merely repairing the lines, worker break and remove the old ones and replace with new ones. As such, there is some trenching work that must be accomplished before rehabilitation.

Heavy equipment including a compressor, winching trainer, cable, and frame are necessary to complete the process. Also, the use of a pneumatic bursting tool and expander cone break up the old pipe while pulling the new one into place.

This method of trenchless rehabilitation began in earnest in the early 1980s. At that time, companies used impact moles and ramming machines to break up the pipe. Today, there is a unique cone-shaped head that helps to create a channel for the new pipe while shattering the old one. Modern methods also use a winch to help pull and guide the bursting tool through the ground rather than ramming it in with a hammer.

Pipe bursting is the most common choice for wastewater management rehabilitation.

Trenchless equipment used in wastewater management allows cities to rehabilitate and create new sewage systems for their residents at significant cost savings. By knowing the conventional methods that workers may employ and realizing the technological advancements, project managers can choose the most efficient equipment and methods for their needs.