Modern waste systems are easy to take for granted. Sewer infrastructure only appeared in cities in the mid-to-late 19th century, and widespread in-home flush toilets became common just a century ago. Compared to thousands of years of prior civilization, our current approach is brand new.
Despite their benefits, modern sewer systems have drawbacks. Flushing with water is hygienic and practical, but wasteful: a 2008 EPA study found the average American household flushes 76 gallons per day, accounting for 27% of indoor water use. Nationwide, toilets alone consume trillions of gallons of potable water annually.
And that’s just toilets. All indoor water becomes wastewater—about 300 gallons daily per U.S. household. For perspective, Lake Mead, the nation’s largest reservoir, holds around 2.5 trillion gallons at current levels. U.S. households use four to six times that volume annually, excluding outdoor use.
This excessive water use is a global concern. Beyond draining reservoirs and harming ecosystems, using potable water for routine tasks strains energy systems and infrastructure. The energy required to transport and treat America’s household greywater each year could power 2–5 million homes.
A key inefficiency is the single waste stream: heavily contaminated “blackwater” and lightly contaminated greywater all flow through the same system. The result is a large volume of wastewater requiring intensive treatment, instead of a smaller, more concentrated stream.
Concentrated waste can be converted into biofuel, compost, or fertilizer. Once mixed with greywater, it becomes harder to recover, while the greywater itself is more complex and costly to purify.
Greywater isn’t the only volume multiplier affecting waste streams. Another overlooked inefficiency is inflow and infiltration (I&I). When groundwater or stormwater enters sewer pipes through cracks, faulty connections, or uncontrolled inflow points, it can dramatically increase the volume of water sent to treatment plants.
I&I is a problem that municipalities across the world struggle with. Cities in Metro Vancouver actually get charged for excess inflow, making proactive inflow management more enticing. Either pay excess fees, or pay to fix the issue!
Water-intensive waste infrastructure is also a challenge for public health. Heavy rain events frequently overwhelm aging sewer lines, pushing untreated waste into local water bodies. When operating at reduced capacity, the Columbia Forcemain in Vancouver requires only modest rainfall to become overwhelmed, dumping massive amounts of human waste into the Burrard Inlet. This is common practice around the world, resulting in everything from outbreaks of illness to algal blooms and “dead spots” that kill off local wildlife.
An alternate tendering process where the contract is awarded to one entity which comprises both engineering and contracting.
Because PW Trenchless Construction offers such innovative solutions for underground utilities, it is often beneficial for the owner to request solutions based on a performance specification. This allows PW Trenchess to offer unique solutions while working with equally innovative engineering companies. Learn more about design - build here!
More InfoNew installation methodologies include HDD & traditional open cut Learn more about new installation here!
More InfoIn this day & age of pipe systems reaching the end of their projected lifespan, pipe replacement and pipe rehabilitation have become major fields of engineering.
PW Trenchless Construction provides viable options such as pipe bursting, loose fit lining and internal pipe re-construction whether partial & fully circumferential. Learn more about pipe replacement & rehabilitation here!
More InfoThe aging culverts under roads and highways in many case have reached the end of their engineered life-span. We consider the rehabilitation or replacement of these culverts to be vital to our built environment.
PW Trenchless has been a pioneer in working with MOTH, railway companies and municipalities in developing rehabilitation methodologies for the hundreds of thousands of culverts that currently exist in BC. We have offered solutions in both procurement and construction from design-build to sliplining, invert rehabilitation and full circumferential relining. Learn more about culvert rehabilitation here!
More InfoOften pipe failure can be concentrated to one section, for various reason, leaving the rest of the pipe in good condition. The repair of these localized failures are know as external point repairs (EPR's).
EPR's demonstrate PW's ability to work as both a trenchless and civil contractor, completing EPR contracts using our civil contracting skills and assisting other pure trenchless contractors who only have the capacity to work in an existing pipe. Learn more about point repairs here!
More InfoPipe upsizing is the fundamental concept of pipe bursting.
The vast majority of pipes are less than or equal to 200mm in diameter, but with today's densification practices of urban design, there is a major demand to increase current capacity to handle extra flow. Pipe bursting provides the ideal solution to this issue, particularly in an urban setting. Learn more about pipe upsizing here!
More InfoHorizontal Directional Drilling is a low impact Trenchless construction service where pipe is installed in a shallow arc along a bore path which has been created by a drilling rig. Often the terms Horizontal Directional Drilling (HDD) and Directional Boring are used interchangeably, but in our industry we use the word “boring” when we utilize smaller sized drilling rigs with small diameters for short crossings in the hundreds of feet, and we use the word “drilling” when we utilize larger rigs with large diameters for long crossings in the thousands of feet. Learn more about horizontal directional drilling here!
More InfoPrimus Line® is a flexible sliplining solution for the trenchless rehabilitation of pressure pipes. The system consists of a flexible Kevlar® reinforced liner and specially developed end fittings. Primus Line® is not bonded to the host pipe and is self-supporting. An annulus remains between Primus Line® and the host pipe.
Developed by experienced engineers, the system is suitable for different media as well as various application needs and has already proven itself in numerous projects.Learn more about primus lining here!
More Info
When you join PWT, you become part of a community of people who are engaged in the most innovative practices in the Trenchless Industry. We have been instrumental in setting up a scientific method for cities to gain carbon offsets/credits from their use of trenchless construction. This system has been reviewed by the BC Government and has been approved as of December 2018. We expect to see it in common use shortly.
Subscribe to our newsletter for cutting-edge industry updates, expert knowledge, and exclusive content.
