Solid Waste II

ENVR 890-2

Mark D. Sobsey

Spring, 2009

Domestic waste composting facilities: A review of human health risks

José L. Domingo and Martí Nadal

Environment International,

Vol. 35, 382–389 (2009)

MSW and Composting

• Collection followed by separation of recyclable and compostable material.

• Diminish significantly the volume of waste to be incinerated or to be deposited in landfills.

• The organic fraction of the MSW is biologically degraded during the composting process

• The final solid residual, the compost, potentially used in various agricultural applications depending on its quality and maturity

MSW Composting and Health

• Prime quality compost is suitable for production of high quality agricultural products

• Secondary quality compost has utility for the improvement of landscape and forests, – Use for the development of agro-tourism and tourism

in general. • Compost is usually not a product considered detrimental

or hazardous to the environment or the public health• The MSW from which it has been obtained can contain

various pollutants pose environmental or health risks– Consider the potential chemical and biological

contaminants contained in the original MSW. • The health hazards are largely posed to workers of

composting facilities and to consumers of vegetables treated with MSW compost fertilizers

MSW Composting Pros and Cons

Pros:• Reduces MSW disposal to landfills and to incineration• Recovers organic matter useful for as soil amendment• Provides employment opportunitiesCons:• Facilities can produce odors, noise, vermin/vestor

nuisances, bioaerosols (organic dust containing bacterial or fungal spores), emission of volatile organic compounds (VOCs)

• Final product used as soil amendment for agriculture can be a potential pathway from use on land for contaminants to enter the food chain

Exposures Risks and Pathways

• Ingestion of soils treated with compost,– especially for pica children

• Contamination through the food chain by consumption of products cultivated in soils where compost has been applied– With time suppose there could be

accumulation

• Dispersion of atmospheric dust of compost– Transport of microorganisms and toxicants

capable of being inhaled

Exposure pathways to pollutants derived from the production and utilization of compost derived from the organic fraction of MSW.

Chemical Risks and Emissions• Metals: arsenic, cadmium, chromium, lead, mercury and

nickel• Pesticides• Organochlorinated compounds such as dioxins and PCBs

(polychlorinated biphenyls)• PAHs• Other Halogenated hydrocarbons.

• Facilities operating at aerobic conditions can procude odor due to VOC emissions, especially from fresh material

• Incomplete processes of aerobic degradation produce emissions of alcohol, organic ketones, esters andacids

• Facilities operating under anaerobic conditions and with insufficient or incomplete ventilation, generate and release sulfured compounds of intense odor

Biological Risks from MSW Composting

• MSW contains organic matter derived from animals, residues of vegetables, and other food process waste, as well as other cellulosic matter.

• Biological degradation in the compost processing of this waste poses multiple exposure opportunities to organic dusts– These can be of vegetable, microbiological, or animal origin

• Individuals handling MSW can be also exposed to infectious microorganisms, including bacteria that have allergenic endotoxins, fungi, and parasitic protozoa.

• Workers of MSW composting facilities are potentially at risk of these exposures.

Health Effects from Microbial Contaminants in MWW and Compost Organic Dusts

• Pulmonary inflammation (acute inflammation, hypersensitive neumonitis), occupational asthma, and chronic bronchitis.

• Gastrointestinal (enteric) illness, fevers, and infections and irritations of eyes, ear and skin

• Potential risks of exposure to pathogenic bacteria and/or endotoxins produced by them, allergenic fungi, and parasitic protozoa.

• Most fungi asociated with MSW and its compost activities are allergenic agents that can cause occupational diseases.

Aspergillus fumigatus (A. fumigatus) and Other Fungi

• Opportunistic pathogenic fungi that produce mycotoxins • Exposure of the nose and throat can cause infections. • Other fungi: Aspergillus flavus, Stachybotrys atra, and

different species of Fusarium and Penicillium – All produce mycotoxins

• Occupational exposure to breathable mycotoxins increases the risk of cancer in workers, – May be due in part, to the deleterious effects of the mycotoxins

on the alveolar macrophages of the lung

• Among the mycotoxins, the aflatoxins produced by several strains of A. flavus and A. parasiticus have been catalogued as mutagenic and hepato-carcinogenic by the IARC

Municipal solid waste management in Indian cities – A review

Mufeed Sharholy, Kafeel Ahmad, Gauhar Mahmood and R.C. Trivedi

Waste Management, Vol. 28: 459–467 (2008)

Per capita generation rate of MSW for Indian cities

Municipal Solid Waste Physical Composition - India

Physical and Chemical Properties of MSW by City Size - India

Collection efficiency of MSW for Indian cities

MSW Collection Efficiency - India

Collection efficiency (CE):amount of MSW collected & transported from streets to disposal sites ÷ total amount of MSW generated in same period.A function of 2 key factors: - Manpower availability &- Transport capacityHigh where private contractors and NGOs collect and transport MSW. Most cities are unable to provide waste collection services to all parts of the city.Often, overcrowded low-income settlements lack MSW collection and disposal services.These settlements are often illegal. Inhabitants are unwilling or unable to pay for services. They discard waste near or around their houses at different times, making collection & transport difficult.