McCommas Bluff Sanitary Landfill, Dallas

Date ant Time:  July 30, 2011  12:00Noon

Tour Guide:  Jon Picha

                    McCommas Bluff Sanitary Landfill

This is the largest landfill in Texas and is owned and operated by the City of Dallas.  It accepts waste from City collections as well as commercial haulers.  The area owned by the City encompasses 2000 acres of which approximately 1000 acres is currently being used by the landfill.  The landfill is bordered on the east by the Trinity River.  Much of the site is in a flood plain area.  The elevation of the landfill begins at approximately 320 feet and will extend up to a maximum of 550 feet.  Presently, they are up to 490 feet elevation.

McCommas Bluff Landfill Site Plan

Approximately 600,000 tons of waste is generated annually by the residents.  It is estimated that the landfill can serve current needs for about 120 years; however, new technology will possibly replace the need for landfills in about 50 years.  Currently ‘Dirty MRF’ systems for recycling waste are being tested in California.  A ‘Dirty MRF’ system accepts a mixed solid waste stream and then proceeds to separate out designated recyclable materials through a combination of manual and mechanical sorting.  The City of Dallas is investigating using this system to recover recyclable materials.  With this type of system a separate trash bin for recyclable materials would not be necessary.

a 'Dirty MRF' system for recycling of domestic waste

The McCommas Landfill is using ‘Enhanced Leachate Recirculation’ which introduces liquids into the landfill to increase production of landfill gas and also helps speed up the waste decomposition process.  When water percolates through waste, Leachate is the liquid that is produced.  Depending on the waste in the landfill, Leachate can be harmless or toxic.  There are currently water retention ponds at the site.  The water from these ponds is being pumped into the landfill.  Leachate goes to a storage tank and eventually gets pumped back into the lake.  It is not used for anything else.

landfill showing leachate piping

The leachate system is designed as a ‘layered’ system.  Leachate pipes are embedded into the landfill at every two ‘lifts’.  Each ‘lift’ being approximately 20 feet.  This means there is a new water line every 40 feet.  Every other ‘lift’ also gets a gas line.  There is a layer of ground glass at each ‘lift’ that helps percolate the water into the soil.  You can see where the gas is being extracted along the perimeter of the landfill.  There is a system for monitoring if there is gas escaping from the site.  Following is a picture of the gas extraction pipe.  These can be found along the perimeter of the landfill.

gas extraction pipe

Currently, Dallas collects approximately 5 Million cubic feet of landfill gas daily.  This gas is sold to a public utility for royalties in the amount of $1.2 Million per year.  If you include tip fees, the landfill generates revenues of approximately $15-$20 Million annually for the City of Dallas. 

Here is a short video that shows an example of a ‘Landfill Gas to Energy Power Plant'.

Following is the web page for the landfill:
 http://www.dallascityhall.com/sanitation/mccommas_bluff.html

River Legacy Living Science Center

Date ant Time:  July 30, 2011  10:00am

Tour Guide:  Anne Alderfer, Master Naturalist

                    River Legacy Living Science Center

The River Legacy Living Science Center was built in 1988 through a partnership between the City of Arlington and a private foundation as an education center and is at the gateway to River Legacy Parks in North Arlington.  River Legacy Park encompasses 400 acres and includes over 16 miles of trails.  The building was designed by Jones Studio and includes various sustainable features.

interior view of Science Center

Some of the sustainable features in the Science Center and grounds include:

• Modular pavers in the parking lot that are porous and shaped to allow air and water to recharge the soil.
• The decking outside of the building is made of a composite of reclaimed plastic and waste wood.  It uses no virgin wood and is 100% recyclable.
• The restroom wall tiles in the building are made from recycled crushed auto windshields.
• Composite lumber used in the building is a mix of wood shavings that come from small diameter trees of second or third growth.  It uses much of the tree that is ordinarily thrown away.
• The carpet uses synthetic fibers and backing that can be continually recycled and reused.
• The building uses a grey water treatment system that reduces waste water to a clear, odorless liquid in 24 hours.  This water is used in the sprinkler system.
• Trees were relocated and parking lots laid out to minimize impact.
• The nature trail has a mulch covered walk to minimize foot traffic impact on native soils.
• Path surfaces were made from granite dust which is normally disposed of in the quarrying process.  This allows more air and water to penetrate the roots.
• Native plants that are less demanding of water and fertilizer were planted.
• Root watering crystals were used.  They retain moisture thereby requiring less watering of plants.

butterfly display in the Science Center

Anne Alderfer gave us an interesting tour on a nature trail that winds along the vicinity of the Science Center.  This part of the park is in ‘bottomland’ as can be seen by the dense vegetation and by the large trees that grow here.  Anne pointed out the effects that our current draught is having on the vegetation and the mechanisms that plants use to cope with this kind of stress.  Also, she pointed out that some plants, like the Asian Privit, is very invasive and is being removed from the park.  

nature walk trail

On a large Cedar Elm Anne pointed out that the sap suckers (woodpeckers) were attracted to this tree because it was sick. She pointed out how you can tell how they leave their markings on the tree in more of a regular pattern on the bark whereas insects would leave more of a random pattern.  Also, she mentioned that the woody material that is left over from downed trees and limbs becomes a great habitat for creatures and also eventually decomposes and recycles back into the forest floor.  The lake by the Science Center has Tilapia fish and there are Bobcats have been spotted in the park.

To control erosion on the banks of the river that is now dry, they have used rocks held by a wire mesh type of material.  This is more of a sustainable alternative than concrete retaining walls.  See picture below.

Following is the web page for the River Legacy Living Science Center:

www.riverlegacy.org

Korwall Industries, Inc.

Date ant Time:  July 30, 2011  8:00am

Tour Guide:  Stan Dimmick, President

                      Korwall Industries, Inc.

Korwall Industries, Inc. is a small business engaged in the manufacture of structural insulated sandwich panels.  The company was started in 1962 by Stan Dimmick.  Stan mentioned the problems they initially had with inspectors accepting his panel system since they were accustomed to wood stud construction and these panels had no interior structural wood studs.  All codes now accept these panels as an alternate building system.

The panels are constructed of One (1) pound density expanded polystyrene sandwiched between two layers of wafer board (oriented strand board) skins.  The expanded polystyrene has an R-Factor of 4 per inch giving these panels excellent insulating properties.

typical panels

Homes manufactured with this system can have various roof configurations including hip, gable, gambrel and mansard.  This construction system makes for a very tight building having been tested to a negative air pressure of only ½ air change per hour.  This compares with conventional home construction at 4 air changes per hour.  This results in added energy efficiency.  Stan recommends using a good quality insulated window in the building envelope.

The panels are manufactured in dimensions of 8 ft x 24 ft.  The thicknesses are nominal dimensions as per conventional construction such that a 4 inch panel is really 3.5 inches.  Stan estimates that the panels are 4x stronger than conventional wall studs.  In the construction of a building, each panel has its own drawing also showing location of electrical outlets and any necessary penetrations.  The joining of the panels are done with one panel having a male wood spline and the adjoining panel having an indentation.

Following are photos showing the procedure for making the panels.  You have 45 minutes from the time you lay the catalyst to putting the panels in the press under pressure in order to adhere the skins to the expanded polystyrene.

rolles for applying adhesive to the panels

skins are bonded to the polystyrene under pressure

The structural and insulating properties of these panels make them suited for exterior walls and roof construction.  An 8 inch panel used for roof construction can clear span 16 feet with a 27 lb per square foot loading.  They are not used for second story floor construction as there is no necessary for an insulating panel inside a conditioned space.  Also, ground floor construction is more cost effective using a concrete slab on grade.  If panels are used for floor construction they need to be overlaid to prevent puncture.  6 inch panels have been used in the Gulf Coast and are able to withstand 120 mph wind loads.  The panels come with a lifetime guarantee. (not including damage from floods or abuse)

typical construction using sandwich panels

connection of roof to wall system

At the present time the wafer boards can be recycled but the expanded polystyrene is used for filler material for packing.

Following is the web page for Korwall Industries:

www.korwall.com

Green Phoenix Farms - Aquaponics

Date and Time:  July 26, 2011  7:30pm

Presenter:  Adam Cohen

                  Green Phoenix Farms

Adam received his B.S. in Marine Biology and his B.S. in Marine Fisheries.  He has been in business for about a year and recently received his business license 6 weeks ago. 

Adam gave us a comparison between Hydroponics and Aquaculture.  With Hydroponics, you can produce great yields, control every factor and grow plants without soil but the nutrient solutions tend to be very expensive as they can be used for only 2 or 3 weeks and then they need to be drained from the system or they become toxic to the plants.  Aquaponics is the bridge between hydroponics and aquaculture.  It is a naturally balanced system in an artificial environment.  Water circulates from the fish pond, gets detoxified by the plants and then goes back to the fish pond.  The waste from the fish is converted to fertilizer that feeds the plants.  Following is a short video on hydroponic lettuce production.

Adam’s inspiration for becoming involved in Aquaponics came from Will Allen of ‘Growing Power’ located in Milwaukee which is a community based urban farm that grows food for local groceries and restaurants.  Will has been in operation for 24 years and currently has 60 full time staff.  He also teaches people to be self sufficient through Aquaponics.  Following is a short video of his operation:

Another source of information on Aquaponics can be obtained from Travis Hughey: Barrelponics.  Travis uses 55 gallon drums for his system.  Adam patterned his 750 gallon prototype system from Travis’ design and also uses 55 gallon drums that have been cut in half.  He has 60 square feet of growbed space and raises approximately 100 pounds of Tilapia fish.  He wants to develop a version of his system for developing countries.

Adam's backyard 750 gallon system

There are three types of Aquaculture systems currently in use:

• Ebb and Flow:  water level goes up and down
• If you aerate the water you don’t need to change the water level and the plants do better.
• Continuous Flood:  tank is on bottom
• Raft Style:  similar to traditional hydroponic system with tank at end

Raft Style system

Plants grow bigger, faster and stronger in Aquaponics.  They have not found a plant that will not grow with Aquaponics.  Pineapples have been grown.  Even a papaya tree was grown that produced large papayas.  You are only limited by the seeds that you can obtain.  1 pound of fish will need 4 gallons of water and a 1 gallon fishtank will fertilize a 2 gallon growbed.

In DFW there is the DFW Aquaponics group that meets once a month.

Following is a link to their web page:

http://www.meetup.com/dfwaquaponics/

Whiz-Q Stone - Water Harvesting

Date ant Time:  July 26, 2011  6:30pm

Presenter:  Matt Reed

                  Whiz-Q Stone

Matt made a strong case for rainwater harvesting.  1 inch of rain on 1 acre generates 27,000 gallons of water.  Unfortunately, harvesting is not economically feasible in DFW due to the low cost and availability of water.  However, it is feasible in locations such as El Paso and areas where digging wells is not feasible due to the quality of water in the water table.  The current draught conditions have also caused some farmers to look at providing their livestock with water from water harvesting.  In Austin you will see many rainwater harvesting systems in suburban residences.

Matt demonstrating the Design Calculator

More and more we are seeing that there is a limited supply of fresh water and in many cases demand is outpacing supply.  Water conservation is becoming a key in many municipalities such as Tucson where water rights have been curtailed and where rainwater harvesting is necessary.  Rainwater harvesting can be used for:

• Landscape irrigation for your lawn and flower beds
• Topping off swimming pools and hot tubs
• Toilet and laundry water supply (where allowed by code)
• Washing your car, patio or deck.

Water storage tanks are available in metal, plastic and concrete.  Matt showed us the ‘Aquablox’ Tank Storage Module which is a lightweight structural catchment system which can create almost any shape and size reservoir.  It is also a structural box that can withstand car loading up to 38 psi.  It is manufactured from 85% recycled Polypropylene and is unaffected by molds, algae, soil-bourne chemicals and bacteria.  The system can be used along with a permeable patio paver.  Installation instructions for this system can be found at:  http://www.rainxchange.com/downloads/aquablox-water-matrix-manual.pdf

the Aquablox Tank Storage Module

Aquablox 1,500 Gallon System

Aquablox System Installation

Storm water runoff is the #1 cause of coastal pollution.  Aging infrastructure in many cities cannot handle large storm surges; therefore, managing storm water becomes a high priority.  In Chicago, mitigation of storm water runoff has become a high priority due to the fact that Chicago does not have separate storm and sewage drain piping.  One piping system serves both which can cause overflow at sewage treatment plants and has resulted in release of sewage into rivers and Lake Michigan.  As a result of this the EPA has fined the City.  There are now strict storm water retention and harvesting requirements there.  Chicago has installed 9 Million square feet of permeable pavers in the last 5 years to control runoff.

Matt also demonstrated a Design Calculator which gives you the projected rainfall in your area by month and then calculates your rainwater storage requirements based on your water use.  This is available at:  http://www.rainxchange.com/calculator.php

Following is a link to their web page:

http://www.rainxchange.com/

Enviroglas

Date and Time:  July 23, 2011 at 12 Noon

Presenters:  Tim Whaley – Founder

                   Esteban Diaz - Operations

                   Enviroglas

‘Enviroglas’ considers themselves a ‘boutique product’.  Their product is recycled ground glass embedded in a quick hardening pigmented polymer based epoxy resin.  Much of this glass comes from the City of Plano which has a glass crushing machine.  Utilizing this 100 % post-consumer glass keeps the material out of landfills.

The installation procedure for Enviroglas is similar to working with terrazzo and workmen are able to use the same type of tools.  The epoxy resin has no volatile organic compounds (VOC’s) so workmen don’t have to use respirators.  They also use‘sand’ made of crushed glass which is combined with the resin.  The ground glass is categorized by color, size, weight and shape.  The mixture is troweled in and polished in a two-step process.  First with wet polishing and then finalized by dry polishing.  The final polishing brings out the color of the glass.  The material is also easy to repair on site.

This material is being used for floors (Enviroplank), countertops (Enviroslab), ceiling panels as well as interior wall panels. It is not recommended for outdoor use as UV rays will degrade the epoxy resin.  Another product they have is called ‘Enviroscape’ which is using recycled glass as a landscaping material.  Commercial installations are their best customers and DFW International Airport as well as Dallas Love Field are using their flooring product.

Following is a link to their website:

http://enviroglasproducts.com/index.asp

Urban Reserve

Date and Time:  July 23, 2011 at 10:00am

Presenter:  Diane Cheatham

                  Urban Reserve

This is a development of single family homes designed by recognized architects.  The development plan uses a concept of ‘ribbons of landscape’ as a unifying force.  There are areas set aside as green areas.  Lot square footage range from 5,000 to 14,000 square feet.  The least expensive lot is $125,000.  The minimum square footage of a home is 1,200 square feet with a maximum being 8,000 square feet.  

view showing one of the water retention ponds

The development includes front yard setbacks of only 10 feet and streets use rollover curbs.  There are two retention ponds in the development to catch runoff.  Rain gardens are also used to filter out heavy metals from rainwater.  Their homeowner’s association guidelines, which can be found online, include a list of plants that are drought tolerant and native to the area.  LEED certification is a requirement for any home constructed in this development.  There have been 16 homes built so far.

Diane is a proponent of using a geothermal system as being the most cost effective for heating and air conditioning with a relatively short payback.  Water conserving fixtures is also one of her recommendations as is composting to minimize trash going to the landfill.  The question of having a ‘community garden’ came up, but this would require re-zoning one of the lots for commercial use which is presently not an option.

Following is a link to the web page:

http://urbanreserve.net/