Waste Characterization Study Provides Detailed Insight into Landfill Composition

Tuesday, August 20, 2019

Stanford University has long been a leader in sustainable materials management, founding its recycling and compost programs nearly 50 years ago. To advance waste management strategies and ensure the university meets its goal of becoming a zero-waste campus by 2030 (90% diversion from landfill or higher), Stanford commissioned a peer review and analysis of its Zero Waste Plan and Feasibility Study. The group conducted a campus-wide waste characterization audit of the university’s landfill, recycling, and compost streams to provide a comprehensive, quantitative analysis of Stanford’s landfill generation.

The audit looked at six building categories, grouped based on similar waste production and disposal patterns, ranging from labs, offices, and cafes to dorms, apartments, and row houses. Consultants conducted sampling over a five-day period, and select routes and containers were brought to a vacant lot where the team characterized all samples. The group collected an average of 20 landfill and 10 recycling and compost samples per category. The landfill samples were hand-sorted into over 48 material categories and weighed, while recycling and compost streams, underwent a visual characterization.

The audit revealed that recoverable food waste was the most significant category found in the landfill,  followed by non-recoverable food waste and bathroom waste (total 36%). Of the six building categories, apartment buildings contribute the highest amount of recoverable materials to the landfill (28%). Cafes, labs, and offices have the second highest amount of recoverable materials in their landfill streams (all 16%), followed by dorms (15%). Rowhouses send the lowest amount recoverable materials to the landfill (9%).

The audit also revealed contamination in the recycling and compost streams, which affects diversion rates. Stanford’s main campus has two recycling streams, one for plastics, metals, and glass (PMG), and another for paper. Sources of contamination for the PMG stream include paper, non-recoverable items, and food waste, while the paper stream was contaminated with food waste, PMG, and other non-recoverable items. Finally, the audit found that the main source of contamination in the compost stream is plastics and plastic composites. View the complete detailed report

The study will help shape the university’s Zero Waste Plan and Feasibility Study to help meet campus, state, and regional regulations and targets.