国产麻豆

Noel Lyons and Lynn Lucas

All life forms, whether plant or animal, rely on a healthy soil and its inherent organic matter (OM) content to provide sustenance and purify water. Unfortunately, in many parts of the world (including the U.S.), the topsoil layer has been stripped and depleted by human activities and is but a fraction of its pre-development depth. Excessive erosion, heavy stormwater flows and a high requirement for chemical fertilizers are indicative of topsoil loss.

Organic matter is what gives topsoil vigor, not only ensuring the porosity required for good root development and air/water movement through the soil, but also providing a welcoming environment for the micro-organisms plants depend on for efficient nutrient uptake and disease suppression. When soil organic matter content is raised to a recommended 3 to 5 percent, there are significant improvements in water retention and filtration, impacting stormwater management, erosion control, pollution abatement and water conservation.

The only practical way to repair the damage resulting from poor soil management is through the addition of compost, and the only practical (and sustainable) source of raw materials for compost manufacture is organic waste. Food, paper, wood, biosolids, cooking oil鈥攁ll of these resources biodegrade, and all of them can be composted at the same facility using a modern, high-rate process.

Developing the required collection systems and processing facilities for topsoil replenishment in the U.S. is not a pie-in-the-sky goal. Provided all parties work together, a 100,000 tons per year operation鈥攆ully enclosed, environmentally-secure and capable of producing premium compost products鈥攃an be permitted and constructed in under two years through public-private collaborations.

How Much Will It Cost?

Based on current construction costs, capital dollars for a modern, high-rate compost manufacturing facility will run $70 to $100 per capacity ton, which means owners of these operations will need to raise more than $6 billion to build the facilities required to compost the 88.3 million tons of paper, paperboard, wood, food waste and yard trimmings still to be recovered from our nation鈥檚 landfills.

Yes, it is a hefty sum. But to put those dollars in perspective, $6 billion was the estimated cost of this year’s presidential and congressional elections, a 鈥減urchase鈥� that must be repeated every four years. The same amount bought a few weeks of games in London earlier this summer.

If weighing the relative worth of these expenditures versus the cost of the repair and restoration of the ecosystem responsible for food production and clean water, investing $6 billion in the soil seems a real bargain. It is a sizeable investment, however, and begs the question: what, exactly, can we expect to get for the money?

• We get jobs. At one job for every 3,000 tons processed at a modern, high-rate facility, nearly 30,000 new jobs paying above the average for most regions will be created when those 88.3 million tons are composted. These jobs offer full benefit packages, and because they provide a local service, the jobs cannot be outsourced.
• We get long-term, predictable management costs for the local governments hosting private-sector composting operations.
• We get a 100 percent reduction in methane generation (compared to landfilling).
• We get compost, about 44 million cubic yards more per year.

When used to raise soil organic matter to the recommended 3 to 5 percent, that compost will also buy us:

• An additional 16,000 gallons water-holding capacity per acre foot for every 1 percent increase in OM. (Source: — USEPA)
• Improved downstream water quality resulting from compost鈥檚 retention/degradation of sediment and pollutants like heavy metals, excess nutrients, oil and grease (Source: 听— USEPA), and the possibility of no runoff following low-to-medium intensity/duration rain events (Persyn et al, 2004).
• Up to a 50 percent reduction in chemical fertilizer requirements (Source: University of Florida IFAS).

Monetizing Benefits, Facing Challenges

The U.S. Composting Council recently released a cost-benefit analysis comparing compost to other agricultural/horticultural products. Among the findings were the following:

Compost also trumps the competition when used to manufacture topsoil on site using native soils instead of buying topsoil鈥攁 typical dollar savings of about 50 percent. In erosion and stormwater management, the use of compost filter socks/blankets eliminates labor and landfill costs related to removal of control devices upon project completion, because compost controls are vegetated and become a permanent feature of the landscape.

Also in the plus column for compost, though not yet monetized, are avoided costs related to labor and equipment use, the reduced requirement for replacement plantings on landscaping projects, and reductions in stormwater infrastructure requirements.

Composting is a practical solution for both organic waste management and soil restoration. Both composting and compost products have environmental and economic value. But that doesn鈥檛 mean converting all this ecologically/economically-beneficial material to highest use won鈥檛 present an intimidating challenge, especially when considering that most MSW numbers do not include compostable water/wastewater treatment residuals, agricultural wastes and/or industrial by-products. In fact, the total volumes of biodegradable waste generation in the U.S. are largely unknown, and there are segments of the MSW waste stream like leather and natural-fiber textiles that are not grouped with compostables in MSW tallies, but will have some compostable content.

There are also logistical problems to work out. Not every composting facility will be able to find a suitable site close to a metropolitan core, necessitating a transition in the makeup of transportation fleets, more transfer stations designed for organics (i.e., direct transfer to transport trailers so no food touches the ground or concrete floors), enclosed trailer bays and/or buildings equipped with biofilters, and fastidious attention to the frequent removal of putrescibles to outlying composting facilities.

But if there is any doubt about the growth potential of organics recycling, one need only look to California and Vermont, where organics recycling is now mandated, and to Denver, where a 2008 Soil Amendment Program requires property owners to provide proof of 鈥減roper鈥� soil preparation before setting new meters, and to the number of private enterprises springing up across the country to collect and compost food waste outside of traditional management systems.

Restoring Balance

On its journey from farm to processing plant to grocery store to plate, more than half of the food produced is wasted. This fundamental problem must be addressed if the collective 鈥渨e鈥� are to feed a hungry planet on dwindling resources. However, cutting back on food waste and improving systems for food rescue won鈥檛 eliminate yard waste or biosolids, which will only increase along with the population. Nor will it fix the soil.

The capture and composting of all organics is not only the most practical and cost-effective way to manage biodegradables; it is the only way to complete the soil cycle. The waste management industry must succeed in its transition from disposal manager to organics recycling facilitator, because it is the fulcrum, the pivotal point, upon which an entire ecosystem balances.

Noel Lyons is president and co-founder of McGill Environmental Systems (Harrells, NC), a leader in the establishment of indoor, industrial-scale composting as a revenue-producing service and recycling technology for mainstream waste management.听

Lynn Lucas is a project developer for McGill Environmental Systems, specializing in business development, communications, marketing and branding.

They can be reached via e-mail at [email protected] or visit the Web site at www.mcgillcompost.com.

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