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Hurricane Ike to Initiate a Municipal Composting Program:
Introduction
Three Sources of Air and Water Pollution
Uses of Municipal Compost
The Math
U.S. Composting Facilities
Further Analysis and Closing Remarks
Composting the 6.5 million cubic yards of debris that accumulated during Hurricane Ike is a tremendously useful solution to eco-friendly waste disposal. Continuing and expanding this process at the scale of a municipal program is a possibility with economic potential as it would decrease the costs associated with landfill use and would create an extremely valuable soil end-product from a highly renewable and accessible resource. The list of environmental merits that composting bestows is a long one. Municipal composting is a feasible and potentially economic solution to reducing, recycling, and reusing our wastes, essentially closing the loop between nutrient input and loss, through the natural cycles as well as through the human cycles of food preparation, lawn maintenance, crop harvesting, and more. It adds one more piece to the effort of ushering change, across the nation, in the sustainable action which builds better, brighter futures. The main focal points of this proposal concern linking city compost with local farms in recycling our wastes, mitigating water and air pollution, generating profit, and providing an incentive for farmers to at least explore compost as an alternative.
Three Sources of Air and Water Pollution
I. 34-37% of the methane gas released in the U.S. comes from landfills. Methane gas is twenty times more potent as a greenhouse gas than the ominous carbon dioxide (1). There are technologies to capture and compress LFG (landfill gas) where it could be directed to a pipeline, offsetting the costs of nonrenewable energy costs, or processed to generate electricity (2), however, if we simply reduce the amount of organic matter piling up in landfills, these procedures are unnecessary. Methane gas is released primarily as a metabolic byproduct of methanogens, bacteria that operate solely in anaerobic environments. In the presence of oxygen, these bacteria simply cannot survive.
The food source of these bacteria is organic wastes, such as kitchen scraps, paper, yard trimmings, etc, reported to amount to 25% of trash in the average American household (3). Recycling organic wastes would eliminate methanogens, resulting in up to a 34% decrease in methane gas released into the atmosphere, and perhaps equally as importantly, this would decrease landfill usage of up to 25%,.
II. According to a paper written by Richard Prosser and Alan Janechek with GC Environmental Inc (4), the four constituents of LFG contribution to groundwater contamination are:
1. direct contact of LFG with groundwater
2. Formation of LFG condensate water in the soil adjacent to landfill
3. infiltration of water carrying volatile organic compounds (VOCs) to the groundwater
4. migration of leachate to the groundwater
III: Another effect on waterways is arguably more troublesome, though less direct. The problems stemming from runoff of nitrogen and phosphorus into rivers and estuaries are based on land usage, primarily dominated by agricultural production. This runoff makes its way into the Gulf of Mexico, causing algal blooms and creating the hypoxic “dead zone” which is predicted to cover a larger dead zone than ever before - greater than the 20,000 km area in 1999. The agricultural regions along the Mississippi River definitely have the largest tally when it comes to eutrophication, but metropolitan Tampa, New Orleans, and Houston are second runners up (5). The compost generated by Houston’s waste management program would have many uses and benefits; one of which could be reduced input of nitrogen and other nutrients into our waterways. Composting has been going on for thousands of years, but surprisingly, the communities who should be most exposed to the practice are often unfamiliar to it and unwilling to try it out on their own. This has to change. Most in this area are receptive to the idea of receiving compost, for free or for a minimal handling fee, as an alternative to expensive fossil fuel based chemical fertilizers. Setting aside a portion of the compost as an incentive to try out alternatives to chemical fertilizers, might be the impetus and support for local farmers to move more towards sustainable farming practices that we and our environment so need (6). There are many creative twists to the program. The “price” for the compost could even be an enrollment fee for a local composting course with the county extension agency. Educational events promoting the incorporation of animal manure into composting practices are important as well, for animal manures are an easy source of stability in the compost, compost offers a safe and effective disposal option, and properly managing animal wastes furthers mitigation of water and air pollution, for they are the source for 10% of the U.S.’s methane gas production (7). For second and subsequent applications, if farmers did not opt to purchase compost from the city, they could make their own using animal wastes or they could arrange to send the wastes to other composting facilities better equipped for the job. Testing procedures to detect contaminates and to ensure stability in the product would be indispensable, especially where chicken poultry, other animal manures, and materials contaminated with herbicides and pesticides were used (8).
Dead zones around the world typically start of with high rates of eutrophication and consequent algal blooms. Loss of critical habitat, biodiversity, and declining fish stocks are not something we want - the Dead Sea, Caspian Sea, and Black Sea can attest to this (9). A recent NRC report called for a minimum reduction of 25% by 2020 (10). Being the 4th largest city in the country, if Houston could pull off a municipal compost-to-farm relationship, the effect on the Gulf Coast waters would be huge. As a model for population centers along the Mississippi River and across the country, Houston would play an important role in addressing this 2020 goal.
Uses for Municipal Compost:
Horticulture, landscaping, and home gardening, in erosion projects, vegetation inputs, storm water management (11), city beautification projects, and agricultural production.
Agricultural production:
1.Soil building - better soil aggregation
2. Soil aeration
3. Water uptake and retention
4. Rich in a diversity of soil flora and fauna (e.g. nitrogen-fixing bacteria & disease-suppressing organisms)
5. Stable source of nitrogen, at up to 60lb/ton and trace nutrients
6. Reduces dependence on fossil fuels
7. Recycles and reuses on-farm green wastes
8. Reduces the ill effects of fertilizers, herbicides and pesticides
9. Contributes to ecosystem functions
10. Reduces run-off
11. Controls and reduces pollutants (12)
12. Buffers stress and disturbance, such as extreme temperature changes and pH
13. Safer for environment
14. Safer for consumer
Note on 8. Organic matter has a stabilizing factor in that it is a soil builder rich in plant matter residue as a source of carbon, nitrogen, phosphorus, potassium, and trace nutrients. Release of nutrients is very slow, and meets the needs of the plants in response to the biological, physical, and climatic factors of the region. Additionally, soil rich in organic matter is alive - it is chock-full of fungi, protozoa, nematodes, aschelminthes, earthworms, bacteria including those which fix nitrogen and much more. Chemical fertilizers, though time-released, do not have the feature of having context-dependent release rates. These fertilizers are applied and released at nearly uniform rates despite the type of soil and amount of rain, rock weathering, and whatever else. They are spent in about six months, then must be applied again at the same application rates to meet the needs of growing plants. While organic matter accumulates over time and lead to stable soil structure, chemical fertilizers do not. The amount of compost needed therefore declines considerably from the first applications to all subsequent applications, while the application rate of chemical fertilizers usually does not vary from year to year.
The Math:
The value of compost lies in the time and effort required to make it. It takes from a few weeks to a year for wood chips to complete the decomposition cycle, where a “sit-and-wait” curing process is recommended for as long as possible. A cubic yard of compost, 3' x 3' x 3', at wholesale prices, goes at around 18$. To cover one acre, 43,560 ft sq, with an ample amount of compost as a first-time application on relatively infertile soils would be about 67.2 cy, 16.1 tons/acre, costing around $1200 at today's wholesale prices. After the initial dosage, the 2nd, 3rd and subsequent applications are significantly less; approximately 1/4 the initial amount, depending on crop being produced, weather, quality of the soil and other factors. Obviously, even if farmers are open to the idea of compost as an alternative to chemical fertilizers, they are often reluctant to experiment as the costs of their own energy in managing it or money in buying it are so high.
The city could implement a composting program and sell compost at wholesale prices. Local businesses such as Living Earth are at full capacity and can not currently facilitate any more debris for the purpose of making compost. The City of Houston should acquire new sites for composting facilities or convert unused landfills to the project. At bare minimum, on a small to moderate scale, one acre of aerated windrows requires top of the line equipment: at least one industrial grade chipper, able to chip to ½ - 1 ½ inch pieces, tractors with front-end loaders, dry screening equipment, and at least two windrow turners. After being chipped, the materials are unloaded at the designated composting sites into double rows of 208ft long, at 12’ by 6’ by 6’ with a 13’ access lane in-between. 208 square feet (approximately an acre) would comfortably fit 11 windrows. To handle every single piece of the Hurricane Ike debris, the city would need about 150 acres devoted to composting facilities, with 100 acres devoted solely to windrows. This requirement seems quite reasonable in consideration of the proposal for a 467-acre IV Landfill in Montgomery County (13). Compost typically takes one year to complete. Where materials enter a landfill to remain indefinitely, compost is changed out with newly deposited material once it has reached completion. Also, the initial amount on 100 acres will diminish from threefold up to tenfold as it releases water and carbon dioxide and plant matter breaks down into soil. At a modest estimate of a tenfold diminishment from the original mass, each acre should yield at the very least around 6,000 cubic yards. If this were sold at wholesale, it would amount to $108,000 acre.
An irrigation system of polypropylene tubing over each windrow would speed things along as temperatures would be in the range of 110 - 150 F, conducive to thermophilic bacteria but none other. This disease-suppressing quality requires oxygen and heat produced by the metabolic activity of a healthy compost heap. It requires the help of mechanical agitation, and does not require sterilization, which would alter the chemical and biological composition of the material in a way that we didn’t want. The outer edges must take turns in the center of the pile, accomplished by a powerful windrow turner in about 4-5 turnings during a timeframe of about 3-6 months. It would be best to time the compost in different parts of the city in order that supply balances out with demand. Using a turning schedule of one turning per acre per 3 months would have all compost ready for sale within six months to a year. With one windrow turner operating at 3,000 cy/hour, it would take 120 - 160 hours in operating the windrow turners per year. With two turners it would be half this amount, about 6-8 typical 40-hr work weeks. The labor cost for windrow turning would be 4,800$ per year. If it took three days to set up deposited material into an acre of windrows, with four operators, it would mean 15 typical 40-hour work weeks to equal $24,000 per year. The rest of the labor and administrative costs would amount to the cost of local collection and delivery, frequent soil sampling and testing, managing community drop-off centers, operating wood chippers and other machinery, and two or more persons in managerial positions dealing with sales, daily operations, and general oversight.
A Few Composting Facilities in the U.S.
Rapid City, South Dakota, has been composting its MSW on a joint yard-trimmings compost facility and materials recovery facility since 1993. The site is adjacent to the 250-acre city landfill. Selling 3/8 inch screened compost at 30$ per ton and 3/8 inch rejects at 10$ per ton, they generate 10,000$ in sales from 4,000 tons in product (14).
Boston is planning an urban composting facility, within the city limits, that would process up to 150 tons per day and operate year round. The operation would be indoors, where methane gas capture would be possible and used to generate electricity. The income would come from selling compost-based fertilizer and energy to supply 1,500 homes. They plan to pick up kitchen trimmings and plate scraps from homes, restaurants, and hospitals in the area (15).
Composting was part of San Francisco’s agenda in when in 2002 63% of the city’s bio-wastes were recycled. Of 1,880,000 tons of waste that year, only 702,000 were actually landfilled. Gloria Chan, DOE’s public information officer, said, “With fuel costs at $2.50 per gallon in the Bay Area, composting our food waste and other organic materials saved a lot of money, and extended our landfill volumes, allowing more room for non-recyclable materials”(16). San Francisco hopes to recycle 75% of its waste by 2010.
The facility in Colbert, Washington, typically processes 40,000 tons of compost on 72 acres and serves as a caveat to the rest of the country. Starting in 1999, there were complaints concerning nursery grown tomato plants showing signs of herbicide related damage. The source was traced to compost contaminated with clopyralid, a herbicide manufactured by Dow AgroSciences. Tomatoes, sunflowers, peppers, potatoes, varieties of poles, and more, were especially susceptible. Like aminopyralid, clopyralid persisted in manures after livestock grazed on sprayed pastures. After an unsuccessful attempt at an entirely different composting method to further encourage breakdown of the chemical into a more benign form, Dow agreed to voluntarily discontinue the residential sale of the herbicide. Municipal compost has the potential of being “food-grade,” provided that regulatory standards must be thorough and regulatory agents must be precautious, attentive, and effective in quickly addressing problems that may arise (17).
Farmers know, maybe more than anyone else, the benefits of rich, dark-brown, sweet-smelling earth. They know the value of aged organic matter as a long-term soil builder, an abundance of mineral nutrients, high capacity for holding water, balanced availability of nutrients, and its overall abundance of soil microbes below ground that translates into an abundance of life above ground. The rich resource of composted green matter could be most valuable to precisely these people, and their use of it could be one of the best options for our long-term sustainability needs. Yet, as outlined above, as a significant input into a large farm, compost is incredibly expensive. Additionally, for certain crops, chemical fertilizers are still necessary as a supplement (nitrogen on corn crop for example). Considering the enormous benefit from more sustainable practices in agricultural production, why not offer the farmers compost, for free, as a first-time application? If the use and management of compost were accepted and turned into conventional wisdom, it would greatly curb our water and air pollution, especially in the decrease in the nitrogen runoff which eventually finds its way into the Gulf of Mexico. Methane gas production could be reduced by up to 10% in managing manure, and up to 34% by keeping wastes out of landfills and out of anaerobic respiration. Depending on the final calculations of operational costs, we could plan on setting aside around 4,000 tons a year for those needing to apply compost for the first time, which amounts to about 1” of compost across 4 acres on 50 farms, at 20 tons/acre. Classes pertaining to composting and manure management are occasionally available through the county extension offices. With this program, we would have to make sure they were available more often, at least on a biannual basis. If the practice of making compost is worth the effort for the farmer, he/she could learn the simple process and continue it for himself. He would have an abundance on-farm resource, which he could mechanically gather, and if that weren’t enough, no doubt he could siphon more materials from the city for a handling fee and/or from his neighbors. We'd better hope that he talks with his neighbors. The efforts of a city composting program would then be shifted to the voluntary efforts of individuals. The benefits remain: healthy land translates into healthier environments, and healthy crops and surrounding environment translate into cost efficiency and better health for us all. With greater numbers of people engaged, and public awareness on the rise, people quickly become acclimated to new ideas, and that which yesterday was unconventional today suddenly finds itself standing in the mainstream. This is what makes people more receptive to change. It is what fosters paradigm shifts, ingenuity, and growth, in individuals and in their communities.
A municipal composting program is essential to environmental responsibility and stewardship. I propose that we continue the current composting programs with some modifications, and let serve the Hurricane Ike debris, waiting to be managed, as the fuel for our municipal composting pilot run. By the method of passive aerated windrows, the most common composting method used by individuals and small and large-scale businesses all over the world, the breakdown process should not create undesirable odors and would take twelve weeks to one year, depending on the frequency of turning, irrigation, and materials used, until completion into a soil end-product that is a “gardener’s gold.” When the compost is done, we test it one last time, distribute it in an incentive program, stagger the sales of it to meet demand, and put it to use in the city.
Works Cited:
1. http://www.epa.gov/methane/index.html
2. CNN cover story of LMOP project
http://www.epa.gov/lmop/video/cnn_story.htm
3. http://www.houstontx.gov/solidwaste/recycling.html
4. Water Pollution Facts
http://www.grinningplanet.com/2005/07-26/water-pollution-facts-article.htm
5. Assessment of Coastal Hypoxia and Eutrophication on U.S. Waters
http://www.oceanservice.noaa.gov/outreach/pdfs/coastalhypoxia.pdf
6. Martin Meyer says that the “ever increasing cost of synthetic nitrogen is forcing farmers to take a look at how they can convert their on-farm waste materials into nitrogen based fertilizer products.”
http://www.jgpress.com/archives/_free/001724.html
7. Livestock Manure Management
http://www.epa.gov/methane/reports/05-manure.pdf
8. Persistent copyralid herbicide in composts
http://www.grrn.org/dow/index.html
9. http://www.economicexpert.com/a/Eutrophication.htm
10. http://www.oceanservice.noaa.gov/outreach/pdfs/coastalhypoxia.pdf
11. http://www.tceq.state.tx.us/assistance/compost/case_studies.html
12. Best Bang for your MSW Management Buck
http://waste.environmental-expert.com/resultEachArticle.aspx?cid=6042&codi=39153&level=1060&idproducttype=6
13.http://www.redorbit.com/news/science/314759/landfill_not_in_their_montgomery_backyard/
14. Rapid City, South Dakota
http://www.rcgov.org/newsletter/past_newsletters/Volume5Issue3.pdf
15. Boston
http://www.npr.org/templates/story/story.php?storyId=88163285
16. San Francisco
http://www.americanrecycler.com/0504municipal.shtml
17. Colbert, Washington
http://www.jgpress.com/BCArticles/2001/070125.html