The Earth Engineering Center of Columbia University

 
THE NYC INTEGRATED WASTE MANAGEMENT  PROJECT 

This is a joint project between the Earth Engineering Center and the Earth Policy Center of the School of International and Public Affairs. The objective is to identify alternatives for increasing material and energy recovery from MSW.  The project is currently funded by the Strategic Initiatives Program of Columbia University. The following summarizes the presentation by the Earth Engineering Center (EEC) of Columbia University at the December 15 meeting of the IMW. It described the current status of a study of environmentally and  economically viable alternatives to the current plan of NYC for out-of-state disposal of the city’s MSW after 2001.
Since last summer, EEC has continued making contacts and developing information on this subject. In particular, the SEMASS Refuse-Derived-Fuel (RDF) power generation plant at Rochester, MA was visited. This plant uses as fuel 3,000 t/d of shredded MSW collected over a 65-mile radius that includes Cape Cod, Martha’s Vineyard and parts of Boston. It recovers metallic values (43,000 t/y ferrous, 4,000 t/y non-ferrous) and generates for sale 550-kWh per ton of RDF. Other contacts included EnergyAnswers Corp. (NY, builders of SEMASS), Resource Recovery Technologies (NY, design of multiple MRF’s and resource recovery plants), Lakeland Electric (FL, users of RDF), Environmental Control Systems (GA, developers of Aerobic Landfill Systems), and Masada Corp. (developers of Middletown, NY, ethanol-from-MSW project).

Also, EEC in January 2000 visited the waste management facilities of Halifax, Nova Scotia, considered to be amongst the most environmentally conscious cities in Canada (two composting plants, one recycling plant, plus in-vessel bioconversion of materials to be landfilled).

By expanding the "blue bag" program to include all "dry" materials (paper, plastic, metal, glass) and placing all "wet" materials in the black bags, and by using best available technology at the MRFs, NYC can increase the amount of paper, plastic, metal and glass recycled and process mechanically the rest to a better grade RDF material. The economic aspects of such a change in the collection system will be discussed with DOS-NYC .

I. CURRENT "BEST PROVEN TECHNOLOGY" (BPT) FOR DIVERTING MSW FROM LANDFILLS:
Three complementary alternatives have already emerged:

1. MECHANICAL PROCESSING/SORTING, ALONE, CAN RESULT TO A MAXIMUM 30% RECYCLING (i.e., 30% diversion from landfill).
   
   
2. COMBINED MATERIALS AND ENERGY RECOVERY IS ONLY PRACTICAL MEANS TO INCREASE DIVERSION TO 90% (an example cited is the SEMASS operation).
   
   The guiding principle here (applied at SEMASS only to metal values) is to recover as much as possible of the solid materials for recycling and use the rest of the MSW as a coal/oil substitute to generate electricity.
   
   
3. MECHANICAL PROCESSING/SORTING PLUS CONVERSION OF "WET STREAM (organic matter)" TO LIQUID/GAS FUEL AND COMPOST PRODUCT: DIVERSION UP TO 65%.
   
   The above technology is proven in Europe but not in the U.S.(1^st large scale application may be in Middletown, NY).

II. DEVELOPING OPTIONS FOR IWM IN NYC

From an environmental point of view, the order of preference of waste management methods (1) is in the order

a) Minimization of waste generated
b) Materials recovery for recycling
c) Energy value recovery by combustion and generation of electricity
d) Landfilling under controlled conditions

The NYC MSW should be managed by a combination of the above methods. A number of options will be examined in detail in the coming months. It should be noted that all of these options require modernized transfer facilities and means of transport, same as in the present plan of NYC. For example, some of the marine transfer stations (MTS) that are to be built or renovated could include a mixed waste processing facility that would recover recyclables from the MSW and prepare the remainder as an RDF (or biofuel feedstock) for transfer/transport to a new plant for energy recovery (or conversion to ethanol).

It should be noted that use of these options would not eliminate landfilling altogether but would reduce greatly the amount of materials that need to be transported and landfilled in other states.

OPTION 1: MINIMUM MECHANIZED SORTING/PROCESSING AND ENERGY RECOVERY

Modern RDF plants are similar to conventional thermoelectric power plants with the exception that they have superior gas handling equipment than many caol-fired power plants in the U.S. For example, the SEMASS plant is equipped with dry scrubbers and bag filters and emits much less NOx and SO2 per kWh produced.

The SEMASS RDF plant produces electricity not from fossil fuels dug out from the earth and transported long distances but by using a fuel generated by the surrounding community. Instead of having to buy this fuel, SEMASS is getting paid to use it because it minimizes the need for landfilling. It is interesting to note that when the SEMASS plant was built in 1988 the "tipping" fees were close to $20 vs the $57 that NYC is now paying for MSW that goes out of state. Thus, what made sense in 1988 makes even more sense in 1999.