by Rick Stryker
More and more, our engineering practice is being asked to help clients
incorporate green products and strategies into our plans and projects.
The clients expect that certain innovative technologies or approaches
will make the world a better place. Here, we will look at a couple of
these alternatives using some examples from building/structures and water/wastewater
treatment.
Remember that the mantra of the day is “reduce, reuse, recycle.”
To begin, we ought to recall the goals of this program in the first place.
Depending on who you ask, it could include either or both of the following
ideas:
- reducing the volume of the waste stream going to the landfill; or
- reclaiming material to save the energy associated with the processing
and manufacture of “virgin” materials.
All in all, metropolitan areas have done the best job in reforming the
American psyche with regard to self-sorting consumer waste. These urban
areas are strapped for space at landfills and are not inclined to pass
the increased tipping fee cost directly to residents. In response, they
have instituted far reaching efforts to get the waste sorted before it
reaches the curb. The good news is that it appears that the direct per
capita landfill tipping volume is holding steady or is down slightly over
the past decades — despite a growing population. The not-so-good
news is that there is a new source of waste products which has emerged
just as the sorting efforts have succeeded. That new source? The recycling
collection centers themselves!
It seems that the education efforts have outstripped the technology
and industrial processes that make the reuse and recycle of sorted items
cost effective. You can liken this to the industrial production of diamonds
or the manufacture of gold from another metal. The energy, time, and effort
are more expensive than the cost of mining diamonds or gold naturally.
There is no market incentive, then, for manufacturers to use “old”
containers. Many recycling processing centers find themselves awash with
carefully sorted, processed post-consumer “raw” material that
gets sent to the landfill anyway for a lack of space.
Recycled Products
Have you noticed the little note on recycled plastic and paper things
that says, “Made with X percent post consumer content”? You
may wonder, “If this is recycled, why isn’t it 100 percent
postconsumer content?” It turns out that each time either plastic
resin or paper pulp is worked, the tiny stringy fibers that give strength
to the product shorten. In turn, this makes the final product weaker.
Even in recycled products, some previously unused base product is included
in the mix. For some applications, any “used” material contributes
a level of unpredictability which consumers will not accept. This is why
paper grocery sacks are often made of virgin pulp — newly cut trees,
not last year’s phone book — and why used plastic grocery
sacks aren’t incorporated into structural plastic lumber. In both
of these green products, new base materials are used to produce a consistent
quality product for their intended markets.
Plastic Lumber
So while using “plastic lumber” means that although trees
weren’t cut down specifically to make the new decking, there were
no old grocery sacks kept out of the landfill either. The base material
is a hydrocarbon polymer produced from crude oil with all of the environmental
and energy issues associated with petrochemical plants producing gasoline
or home heating oil.
Reusing some of the product material will lengthen the time before it
ends in the landfill and reduce the amount of new material which has to
be manufactured. This is precisely why we recommend that existing structures
made from pressure treated (CCA) lumber be dismantled and reused rather
than demolished and dumped. Taking out nails, sorting, stacking, and reusing
lumber is not easy. It is labor intensive and time consuming and will
likely cost more than buying new materials — if you can find them.
Since nothing lasts forever, however, all of these will end up as waste
in some form or another. We have only delayed its arrival there.
Glass
What about glass? The advertisements tell us, “It’s perfectly
clear: Glass Recycles.” Demand for color-sorted crushed glass (called
“cullet”) is often far, far outpaced by supply. Since carefully
sorted and uncontaminated postconsumer glass containers can be melted
and remade at considerably lower temperatures than processing glass from
raw materials, this is one area where the effort at the curb pays off
for the environment. It’s important to be aware that single color
cullet (clear, green, or amber) is much more valuable than mixed cullet
— with the most valuable being that which is free from dirt, stones,
and other contaminants which will appear as defects in the final recycled
product. In short, given glass’s resistance to decomposition, this
is certainly one material which we should work hard to keep in circulation
— and out of the landfills.
Take note of the distinction above about the material being color sorted.
Does your collection and sorting scheme include the sorting of colors
of glass? Once intermixed color glass containers are broken together,
sorting becomes a cost prohibitive, needle-in-the-haystack exercise. This
mixed glass cullet is normally ground down, and its value drops to nearly
zero. After all the time, labor, and energy spent to collect and process,
it actually has negative value.
One innovative use of mixed glass cullet is for filter media in water
filtration plants — swimming pools are included here — and
wastewater treatment plants. Historically, natural sand has been used
to provide a surface on which microbes live and reduce nutrients in the
wastewater to elemental components, detoxifying it for release back into
the environment. The problem is that most quarries have difficulty producing
sand which meets the pretty stringent requirements for sand media in terms
of the particle size distribution and detritus content. Municipal glass
crushing facilities, however, generally seem to be producing a material
acceptable for installation with a minimum of additional processing. And
as mentioned previously, the mixed color cullet has almost no value to
container manufacturers, so most facilities end up dumping this crushed
material in a landfill at relatively high cost. In short, they’re
likely to sell it really cheap! If your facility has a surface sand filter
as part of its wastewater treatment scheme, this may be an option. Check
with your regulating agency which issues and maintains the discharge permit
to see if they have provisions for this media, and perhaps even certified
stockpiles or producers.
Wastewater Treatment
What about wastewater treatment itself? There has been considerable
interest in technologies that are “more natural” than the
“traditional” alternatives — septic trenches, sand mound
systems, and stream discharge plants, to name a few. As addressed in earlier
articles, the decomposition of digestive waste is as natural a process
as there is. Under the best circumstances, nature can be left to take
its normal course and after a time, the waste is reduced into elemental
components and is without biological pathogens. Were this not so, the
forest would be filled with . . . well . . . stuff. But when the occupying
population exceeds the available land space and time for reduction, the
pathogens often cause fatal disease outbreaks or even epidemics. The population
is reduced automatically to levels which can be sustained by the land.
Camps and conference centers are by their nature, community experiences
— concentrating people (and their wastes) to relatively small areas.
Allowed to run its course in this case, the natural waste reduction process
would present a catastrophic public health crisis.
Modern wastewater treatment relies on the same natural biological mechanisms,
but adds components — at least air, in most processes — which
may be consumed completely before the nutrients are completely converted.
By centrally collecting the waste, containing the treatment to a specific
area, adding nutrients at specific times in the process, and monitoring
the resulting products, the detoxifying processes are confined, accelerated,
and pushed toward completion more safely and consistently. None of this
implies that this is a simple process. Quite the contrary is true. The
more concentrated the treatment plant and process becomes — that
is, the number of gallons being treated per square foot of treatment plant
— the more skill is required to manipulate the process times and
ingredients to get the desired level of treatment. All in all, though,
the modern treatment plant digestion process is as natural as it gets
and, when properly operated, delivers predictable, permit-compliant discharge.
What about other natural processes for wastewater treatment? In the
past several years, we have been asked to consider several of these natural
systems. These have included engineered wetlands and similar setups inside
greenhouses. Although research on these methods continues, the Environmental
Protection Agency and state regulators have not included these arrangements
in rules that govern wastewater treatment for a number of reasons. First,
the majority of the engineered wetlands being studied are not being used
as primary treatment, but as a final stage before the water is released
to a stream or other water body (known as “polishing”). That
is, there is normally a traditional wastewater treatment plant upstream
of the wetlands. Second, when compared gallon for gallon of treatment
capacity, wetland systems are substantially larger than their conventional
counterparts, which are often measured in “square feet” as
opposed to acres for wetlands. Next, the highly sensitive nature of wastewater
reduction by plant roots in the wetlands is difficult to predict and quantify
when the flow rates, constituency, and weather conditions all play a most
critical role in the conversion of nutrients in waste water. Regulators,
tasked with preventing degradation of their region’s waters, are
reluctant to permit such an unpredictable process. Along that same line
of reasoning, engineered wetlands are typically permitted to be designed
with a polypropylene or polyethylene liner underneath. This prevents the
unmonitored wastewater from being leaked into — and perhaps contaminating
— the ground water table beneath. Lastly, the lack of documented,
full-scale operational, industry-based experience with these sorts of
systems makes them appear to be a liability from a permitting and regulatory
standpoint (EPA 625/1-81-013; EPA 832-R-93-005; EPA 625/1-81/013a).
We’re often asked about a certain treatment method (“It’s
patented!” we’re told.), which encloses the process in greenhouses
and claims that solar power (in the form of photosynthesis) drives the
process. This particular arrangement was the object of a $7.2 million
dollar EPA research study over five years (1992 – 1997), which found
that, although the vegetation was aesthetically pleasing, the treatment
quality claims of the manufacturer were unsubstantiated — and that
the electrical power requirements (for pumps, aerators, and heat for the
greenhouses) were nearly identical to those for a conventional treatment
plant of equivalent size. Further research funding was not provided (EPA
832-R-97-002). The point here is that while this arrangement may be more
visually pleasing, the regulators charged with ensuring clean, safe water
for everyone have determined that the process wasn’t sufficiently
reliable or effective to make it an attractive option for most applications.
Contribute to the Solution
How can camps and conference centers contribute to the solution and
not be part of the problem? The camp or conference center in the right
geographic spot and within a progressive regulatory jurisdiction could
provide a wonderful opportunity for innovative systems, methods, and materials
to gain a foothold on the “born again” materials industry.
If sorting the waste stream isn’t part of your program — and
staff operations — yet, institute one, and contract with a reputable
hauler to be certain that your efforts aren’t wasted. If available
land area is an issue locally, perhaps your camp could lease a couple
of acres to the local processor. But also, be well informed about the
products and processes which appear green at first glance. There may be
more than meets the eye.
References
Process Design Manual, Land Treatment of Municipal Wastewater, EPA, USACOE,
Department of the Interior, (EPA 625/1-81-013).
Constructed Wetlands for Wastewater Treatment
and Wildlife Habitat: 17 Case Studies, (EPA 832-R-93-005).
Process Design Manual, Land Treatment of Municipal
Wastewater, Supplement on Rapid Infiltration and Overland Flow, (EPA 625/1-81/013a).
Response to Congress. Wastewater Treatment Technology,
(EPA 832-R-97-002).
Originally published in the 2003 November/December
issue of Camping Magazine. |
