Project Abstract

This capstone will develop a data visualization tool to illustrate the lifecycle costs and benefits of leveraging late 20th century technology to solve a 21st century problem—the need to achieve zero waste and reduce CO2 emissions– as compared to the current use of 19th century (and earlier) technology.

Project Description & Overview

The City’s current policy for residential organic food waste diversion has been a voluntary composting initiative with Department of Sanitation (DSNY) pickup in certain neighborhoods. This policy relies on 19th century (and earlier) technology whereby people collect refuse for pick up and transportation by truck. The future policy debate is likely to be about whether to mandate residential organics diversion on a citywide basis with citywide DSNY pickup and transportation. The multi-year voluntary organics curbside collection program has not been cost effective, with approximately half of the City’s municipal solid waste (MSW) going to landfills. To reduce total program costs below current costs would require either a diversion rate of about 30% or a lower diversion rate with reducing processing costs, with associated increased operation costs, before seeing reductions in the distant future. All this would require a long-term concerted effort prioritizing organics diversion, possibly through fines, and changing residents’ behavior.

At no time has there been consideration of leveraging late 20th century technology, in the form of food waste disposers (FWDs), commonly known as “in sink” garbage disposals, to process organics as a means to reduce CO2 emission and achieve “zero waste” goals. Since October 1997, the City has permitted residential households to install FWDs. A study of the impact for FWDs in the City’s combined sewer areas, assuming FWDs would be installed at a rate of 1%/year, found de minimis increases in City sewer maintenance costs, water consumption, wastewater treatment and biosolids handling costs, water rates, and negative impact on surrounding waters, and costs savings from solid waste export reduction. As of 2008, it was estimated that less than 1 percent of NYC households had installed FWDs. 

The benefits and costs of expanding FDWs at food service establishments, studied in 2008 , would apply to mandated expansion of residential FDWs as an alternative to mandated citywide organics diversion. Benefits would include efficiency with related cost savings at the residential sites; associated reductions in municipal truck trips, with labor cost savings, and localized reductions in truck traffic; and beneficial end re-use of food waste, at the city’s water pollution control plants, now rebranded as wastewater resource recovery facilities (WRRFs), with some increases in digester gas, which, with capital investment to modify the WRRFs, could be reused in WRRF boilers to provide heat for the treatment process (cogeneration), with elements of resulting biosolids available for other beneficial end uses, some with commercial applications, and associated revenues. Costs to be balanced against benefits include incremental water use increases; increased sewer maintenance costs and the potential for sewer backups, which until the City resolves its combined sewer overflow problem could result in increased discharges during heavy stormwater events into surrounding waterbodies; and increased capital investment at the WWRFs.

Datasets

This project will use publicly available Department of Buildings plumbing permit data for Downtown Brooklyn and Long Island City and associated publicly available DSNY and Department of Environmental Protection operations and capital cost data. Additional city-produced reports and studies from other cities that have mandated FDWs will be sources of additional data.

Competencies

All students should have proficient data analytic skills. An interest in zero waste and large system operations would be helpful.

Learning Outcomes & Deliverables

The deliverables will be an interactive visualization of a comparative lifecycle cost benefit analysis of the two types of organics diversion technology and a final report that provides the methodology and analyses used and findings.

1. As part of the research component, the students will gain a deep understanding of the City’s municipal solid waste problem and its operations under aspirations to reach zero waste goals.
2. This data manipulation and visualization will enable the students to use all data analytic skills learned to date and possibly require them to pick up other techniques required by the project.
3. If time permits and the students develop theories, students will also develop performance metrics and predictive models.

Students

Zihao Feng, Emma Keogan, Hongjiang Ye