Ed ClericoSpecial to The Gazette
Access to abundant high quality water was typically the major driver that spurred the creation of most of our great cities. Whether it was the blessing of a protected seaport, a nutrient rich floodplain, favourable rainfall patterns for crops, hydraulic power for mills or simply to have good quality supply to quench the thirst of a concentrated population, water was the key factor that allowed cities to thrive in one location but caused them to falter in another. An equally significant factor was the capacity for good waste disposal via access to flowing water or open oceans.
We credit the Romans with building some of the earliest and most sophisticated sewer systems that, together with their picturesque aqueducts, helped protect the public health of their cities by continuously moving human wastes away for downstream disposal. It also began the cultural practice of using “dilution as the solution to pollution” and created linear systems that collected valuable resources from “upstream” supplies and discarded wastes into “downstream” receptacles, typically our waterways and oceans.
When these practices where first employed, they worked very well. The contaminants were all composed of readily degraded organic materials and the overall population of the world was still small, so overloading of waterways was local in nature and easily ignored.
However, the adequacy of this linear approach in the 21st century must now be questioned. The rapid expansion of technology in the industrial sector has outpaced humanity’s capability to devise means and mechanisms for affordably and dependably managing a rapidly growing number of less biodegradable contaminants and an explosive expansion in population.
The changing climate has exposed many well-watered regions to droughts, such as is the case in California. This has encouraged technological development of sewage treatment processes which enable water reuse and improved efficiency via thermal energy capture and renewable energy from biosolids as a more sustainable approach.
Innovation in the water sector is now ramping up to the pace seen previously in the communications and information technology industries, and this is providing solutions that are lower cost, more effective and more adaptable to future changes. Building large scale Romanesque infrastructure is now no longer the only approach. However, after 2,000 years of dependable service, it should not be surprising that some communities such as the Capital Regional District are reluctant to make the shift.
Now, we see many cities and countries embracing means of direct and indirect water reuse as core components of their wastewater management. Smaller “decentralized” systems are now becoming the wave of the future for what many call “smart water.”
A lot has changed recently to bring urgency to this approach. Rising sea levels and changing weather patterns have increased the cost and vulnerability of the traditional water and wastewater infrastructure model. Innovations in biological, chemical and physical treatment of sewage, taken together with rapid improvement in automation of system management, now allow highly efficient small systems to be customized for specific service areas and customer needs.
In the U.S., 13 cities and nine states have formed a stakeholders group that is advancing specific guidelines for use of decentralized small-scale systems of this nature. In addition, San Francisco and New York City have implemented incentive programs to encourage their use.
Recently I was asked to review a proposal from the municipalities of Colwood and Langford to develop a small-scale decentralized treatment plant based on advanced technology as noted above and reuse all the treated water for groundwater recharge either for irrigation, stream augmentation or aquifer recharge. I was impressed that this proposal is technically sound and can be undertaken at a fraction of the cost to homeowners compared with sending their sewage to a central plant.
It illustrates the new potential of emerging technology, lower costs and total reuse of resources that fits the new reality of these decentralized systems, and which can make these two communities leaders in 21st century revolution.
Ed Clerico is CEO Emeritus of New Jersey-based Natural Systems Utilities, which has designed and built decentralized systems for advanced treatment, and water and energy reuse for 20 years.
