23 Solid and Hazardous Waste

Transcription

1 23 Solid and Hazardous Waste

2 Overview of Chapter 23 Solid Waste Waste Prevention Reducing the Amount of Waste Reusing Products Recycling Materials Hazardous Waste Types of Hazardous Waste Management of Hazardous Waste

3 Waste electronics Computers replaced every ~18-24 months Perceived and often obsolete soon E-waste electronic waste of high quality plastics and metals that comprise computers (and phones) U.S. 30kg per person annually Business of recycling e-waste Selling recyclable electronic products Ship most e-waste overseas (disassembly can increase exposure to hazards)

4 Solid Waste U.S. generates more solid waste per capita than any other country 1.99kg (4.38lb) per person per day 251 million tons in 2012 (increase from 2010) Waste generation is highest in developed countries Instead of repairing items, they are replaced

5 Types of Solid Waste Municipal solid waste Solid material discarded by homes, office buildings, retail stores, schools, etc. Relatively small portion of solid waste produced Non-municipal solid waste Solid waste generated by industry, agriculture, and mining

6 Composition of Municipal Solid Waste

7 Disposal of Solid Waste Three methods Sanitary Landfills Replaced open dumps Incineration Recycling

8 Sanitary Landfill Compacting and burying waste under a shallow layer of soil Most common method of disposal Problems Methane gas production by microorganisms Contamination of surface water & ground water by leachate Not a long-term remedy Few new facilities being opened Closing a full landfill is very expensive

9 Sanitary Landfill

10 Sanitary Landfill Special Problem: Plastic Much of plastic waste is from packaging Chemically stable and do not readily break down and decompose Photo and biodegradable plastics Special Problem: Tires Made from materials that cannot be recycled Can be incinerated or shredded

11 Incineration Volume of solid waste reduced by 90% Produces heat that can make steam to generate electricity Produce less carbon emissions than fossil fuel power plants Byproduct Bottom ash Fly ash

12 Incineration - Types of Incinerators Mass burn (below), Modular, Refuse-derived Mass burn, waste to energy incinerator

13 Incineration - Problems Production of hazardous air pollutants Carbon monoxide, particulates, heavy metals Reduced by Lime Scrubbers Electrostatic Precipitators Byproduct - Bottom ash (slag) and Fly ash Must be disposed of in hazardous waste landfills

14 Composting Municipal Solid Waste Composting Includes: Food scraps, Sewage sludge, Agricultural manure, Yard waste Reduces yard waste in landfills Can be sold or distributed to community Concern over heavy metals

15 Waste Prevention Three Goals 1. Reduce the amount of waste 2. Reuse products 3. Recycle materials

16 Reducing Waste Purchase products with less packaging

17 Reducing Waste Source reduction Products designed and manufactured to decrease the volume of solid waste Reuse and recycle wastes at the plant where they are generated 35% weight reduction in aluminum cans since 1970s Pollution Prevention Act (1990) Dematerialization Progressive decrease in the size and weight of a product as a result of technological improvements

18 Reusing Products Refilling glass beverage bottles used to be standard Heavier glass required in reusable glass bottlescosts more to make and transport Cheaper to use lightweight, non-reusable glass Japan recycles almost all bottles Reused 20 times 11 U.S. States have deposits on cans and bottles to promote reuse

19 Recycling Materials Every ton of recycled paper saves: 17 trees 7000 gallons of water 4100 kwatt-hrs of energy 3 cubic yards of landfill space Recycle Glass bottles, newspapers, steel cans, plastic bottles, cardboard, office paper

20 Recycling U.S. recycles 38% of Municipal Solid Waste Recycling Paper U.S. recycles 62.1% Increased due to consumer demand for recycled paper products Recycling Glass U.S. recycles 25% Costs producers less than new glass (right)

21 Recycling Recycling Aluminum Making new can from recycled one costs far less than making a brand new one (economic incentive) 55% of aluminum was recycled in 2012 Recycling Metals other than Aluminum Metal recycling influenced by economy Lead, gold, iron, steel, silver and zinc Metallic composition is often unknown Makes recycling difficult

22 Recycling Recycling Plastic 14% of all plastic is recycled (2012) May be less expensive to make from raw materials 31% of PET in water and soda bottles is recycled Most plastic containers are made of many types of plastic that must be separated to be recycled

23 Recycling Recycling Tires 45% recycled in 2012 Few products are made from old tires Playground equipment Trashcans Garden hose Carpet Roofing materials

24 Integrated Waste Management

25 Hazardous Waste Any discarded chemical that threatens human health or the environment Reactive, corrosive, explosive or toxic chemicals 1% of waste stream in U.S. Love Canal (1977) Classic case of hazardous waste contaminating human and environmental health Love Canal Toxic Waste Site

26 Hazardous Waste

27 Hazardous Waste Dioxin Formed as byproduct of combustion of chlorine compounds (medical waste incineration and others) Bioaccumulates and biomagnifies through food web Causes cancer, effect reproductive, immune and nervous system Polychlorinated Biphenyls (PCBs) Used as cooling fluid, fire retardant, lubricator Disposed of in open dumps, sewers and fields in 1970s - issue in groundwater today Endocrine disrupter

28 Case-In-Point Hanford Nuclear Reservation

29 Management of Hazardous Waste Chemical accidents National Response Center notified Typically involves oil, gasoline or other petroleum spill Current Management Policies Resource Conservation and Recovery Act (1976, 1984) Comprehensive Environmental Response, Compensation, and Liability Act (1980) Commonly known as Superfund

30 Superfund Program Cleaning up existing hazardous waste: 400,000 waste sites Leaking chemical storage tanks and drums (below) Pesticides dumps Piles of mining wastes >10,000 hazardous sites qualify

31 Management of Hazardous Waste Superfund National Priorities List 2014: 1,326 sites on the list States with the greatest number of sites New Jersey (114) California (97) Pennsylvania (95) New York (86) Michigan (65)

32 Management of Hazardous Waste Biological Treatment of Hazardous Chemicals Bioremediation - use of bacteria and other microorganisms to break down hazardous waste into relatively harmless products 1000 species of bacteria and fungi Time consuming Inexpensive Phytoremediation- use of plants to absorb and accumulate hazardous materials in the soil Phytoextraction Ex: Indian mustard removes heavy metals

33 Examples of Phytoremediation

34 Management of Hazardous Waste 1) Source reduction 1) Most effective 2) Conversion to less hazardous materials 3) Long-term storage

35 Hazardous Waste Landfill