Residential Refuse Research Articles

Sector arc routing-based spatial decision support system for waste collection in Brazil.

We present a sector arc routing problem-based spatial decision support system technology to develop tactical and operational plans and manage solid waste collection activities including household refuse collection and human and mechanical street sweeping. The proposed technology can also manage solid waste services through optimization (minimizing sector costs, distances and resources). The proposed technology is called optimized planning and integrated logistics management. It can be directly applied to Brazilian municipalities as it contains its major natural features. The system uses advanced technics from sector arc routing and sector scheduling, fleet and staff scheduling and daily plan management using mobile smartphone apps. The technology also allows for waste system inspections that are transparent to all participants in real time. We present the results of cases evaluated in the field for residential refuse collection and human and mechanical street sweeping in two Brazilian cities (Campo Grande and São Paulo). The plan implementations achieved from 12 to 28% actual fixed and variable cost savings for sectors (vehicles and workers) and routes (time and distances) for residential refuse collection and from 7 to 42% savings for human and mechanical street sweeping for the companies.

Performance Management in Local Government: The Application of System Dynamics to Promote Data Use

The purpose of this article is to demonstrate how system dynamics can be used to enrich performance management in local government, focusing specifically on how the development of conceptual and simulation system dynamic models can foster a shared view of the relevant system among stakeholders to overcome factors that limit data use. Responding to this purpose, we present a normative case study on how key drivers can be used to foster a shared view of the residential refuse collection system for supporting policy and process changes. A major finding from our research, however, is that performance management cannot overlook the broader forces of citizenship outcomes that impact the community.

Semivolatile and Volatile Organic Compound Emissions from Wood-Fired Hydronic Heaters

Emissions including polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), polyaromatic hydrocarbons (PAHs), and volatile organic compounds (VOCs), were sampled from different wood-fired hydronic heater (HH) technologies. Four commercially available HH technologies were studied: a single-stage conventional combustor with natural updraft, a three-stage downdraft combustion system, a bottom-fed pellet burner, and a two-stage heater with both a combustion and gasification chamber. The fuel consisted of three wood types (red oak, white pine, and white ash), one hardwood pellet brand, and one fuel mixture containing 95% red oak and 5% residential refuse by weight. The various HHs and fuel combinations were tested in a realistic homeowner fuel-charging scenario. Differences in emission levels were found between HH technologies and fuel types. PCDD/PCDF emissions ranged from 0.004 to 0.098 ng toxic equivalency/MJ(input) and PAHs from 0.49 to 54 mg/MJ(input). The former was increased by the presence of 5% by weight refuse. The white pine fuel had the highest PAH emission factor, while the bottom fed pellet burner had the lowest. The major VOCs emitted were benzene, acetylene, and propylene. The highest emissions of PAHs, VOCs, and PCDDs/PCDFs were observed with the conventional unit, likely due to the rapid changes in combustion conditions effected by the damper opening and closing.

Comparison of Bacteria and Archaea communities in municipal solid waste, individual refuse components, and leachate

Refuse decomposition in landfills is a microbially mediated process that occurs primarily under anaerobic conditions. Because of limited moisture conditions, hydraulic transport as a means of cellular translocation within the landfill appears limited, especially during the initial stages of decomposition. Thus, microbial communities within the incoming refuse serve as a primary source of facultative and obligate anaerobic microorganisms that initiate refuse decomposition. Fresh residential refuse was collected five times over 26 months, and microbial communities in these samples were compared with those in individual refuse components and decomposed refuse. Bacterial and archaeal community structures were determined using T-RFLP. The Bacterial microbial community richness was correlated (r(2) = 0.91) with seasonal differences in ambient air temperature. Analysis of the results shows that fresh refuse is most likely not the source of methanogens in landfills. Microbial communities in the solid and leachate phases were different, indicating that both matrices must be considered when characterizing microbial diversity within a landfill.

Quantitative determination of fluorochemicals in municipal landfill leachates

Twenty-four fluorochemicals were quantified in landfill leachates recovered from municipal refuse using an analytical method based on solid-phase extraction, dispersive-carbon sorbent cleanup, and liquid chromatography/tandem mass spectrometry. The method was applied to six landfill leachates from four locations in the US as well as to a leachate generated by a laboratory bioreactor containing residential refuse. All seven leachates had the common characteristic that short-chain (C 4–C 7) carboxylates or sulfonates were greater in abundance than their respective longer-chain homologs (⩾C 8). Perfluoroalkyl carboxylates were the most abundant (67 ± 4% on a nanomolar (nM) basis) fluorochemicals measured in leachates; concentrations of individual carboxylates reaching levels up to 2800 ng L −1. Perfluoroalkyl sulfonates were the next most abundant class (22 ± 2%) on a nM basis; their abundances in each of the seven leachates derived from municipal refuse were greater for the shorter-chain homologs (C 4 and C 6) compared to longer-chain homologs (C 8 and C 10). Perfluorobutane sulfonate concentrations were as high as 2300 ng L −1. Sulfonamide derivatives composed 8 ± 2.1% (nM basis) of the fluorochemicals in landfill leachates with methyl (C 4 and C 8) and ethyl (C 8) sulfonamide acetic acids being the most abundant. Fluorotelomer sulfonates (6:2 and 8:2) composed 2.4 ± 1.3% (nM basis) of the fluorochemicals detected and were present in all leachates.

Effect of biosolids on refuse decomposition and phosphorus cycling

Laboratory-scale reactors containing mixtures of municipal solid waste and wastewater treatment biosolids were monitored to assess the effect of biosolids on refuse decomposition and on phosphorus (P) cycling and speciation among orthophosphate, acid-hydrolysable P, and organic P. The co-disposal of 10 to 20% (by wet weight) aerobically-digested biosolids with residential refuse was compatible with refuse decomposition although the biosolids did not increase either the maximum methane production rate or the cumulative yield, and did not reduce lag times to the onset of methane production. The results of this study indicated that dissolved reactive phosphorus (DRP) was the dominant dissolved P fraction throughout refuse decomposition and that it was negatively correlated with the methane production rate and pH (r² = 0.35 for both). P was not found to limit methane production. Biosolids increased dissolved P as well as ammonia-N in some reactors, but this did not have a significant impact on maximum methane production rates. The maximum tolerated Na+ and K+ concentrations during active methane production were at least 4100 mg Na+ L⁻¹ and 800 mg K+ L⁻¹, respectively.

Shear Strength Parameters of Municipal Solid Waste with Leachate Recirculation

The objective of this study was to characterize relative changes in waste shear strength parameters during waste decomposition. Twelve direct shear tests ( 100 mm diameter by 50 mm thickness) were performed on waste specimens ranging from fresh to well-decomposed residential refuse. In addition, nine direct shear tests were performed on selected waste components including fresh paper, partially decomposed refuse, and plastics. Results indicate that the friction angle of refuse decreased with decomposition. As refuse decomposed, the plastic content increased, which contributed to a decrease in friction angle as the friction angle of plastics is 18– 19∘ as compared to 33° for fresh shredded waste. The extent of refuse decomposition was characterized by the cellulose plus hemicellulose to lignin ratio [(C+H)∕L] . The measured friction angle decreased from 32 to 24° as (C+H)∕L decreased from 1.29 to 0.25. The shearing pattern for decomposed refuse showed a peak, followed by residual, which was then followed b...

Release of Trace Organic Compounds during the Decomposition of Municipal Solid Waste Components

Landfill gas contains numerous speciated organic compounds (SOCs) including alkanes, aromatics, chlorinated aliphatic hydrocarbons, alcohols, ketones, terpenes, chlorofluoro compounds, and siloxanes. The source, rate and extent of release of these compounds are poorly understood. The objective of this study was to characterize the release of SOCs and the regulated parameter, non-methane organic compounds (NMOCs) during the decomposition of residential refuse and its major biodegradable components [paper (P), yard waste (YW), food waste (FW)]. Work was conducted under anaerobic conditions in 8-L reactors operated to maximize decomposition. Refuse and YW were also tested under aerobic conditions. NMOC release during anaerobic decomposition of refuse, P, YW, and FW was 0.151, 0.016, 0.038, and 0.221 mg-C dry g(-1), respectively, while release during aerobic decomposition of refuse and YW was 0.282 and 0.236 mg-C dry g(-1), respectively. The highest NMOC release was measured under abiotic conditions (3.01 mg-C dry g(-1)), suggesting the importance of gas stripping. NMOC release was faster than CH4 production in all treatments. Terpenes and ketones accounted for 32-96% of SOC release in each treatment, while volatile fatty acids were not a significant contributor. Release in aerobic systems points to the potential importance of composting plants as an emissions source.

Assessing solid waste recycling opportunities for closed campuses

PurposeThe commercial and residential refuse generated by Ellsworth Air Force Base, USA was characterized and analyzed for collection procedures, and the opportunities for increasing the amount of solid waste that could be recycled were evaluated.Design/methodology/approachRandom loads of hauled solid waste (an average 3.0 US tons/load) from different waste streams of Ellsworth Air Force Base were sorted. The weight fraction of each category of recyclable material derived from the hand sorting operations was applied to the three years of mixed waste tonnage in order to estimate the tonnage of each recyclable category disposed of as refuse during each year. The assessment of the data obtained from three full calendar years focused on the mixed solid waste generated from commercial and residential areas such as offices, childcare, lodging, supermarkets, food service facilities, and others.FindingsOver 2,500 tones of recycling opportunities were missed during the 1999‐2001 calendar years. The characterizations of the total weight produced from commercial and residential waste streams showed that recyclable material constituted 35.95 percent and 23.27 percent of refuse from the commercial and the residential areas, respectively. The amounts of total recyclable material as missed opportunities for recycling were found to be 1,728 tons and 715 tons from the commercial and residential areas.Practical implicationsIn response to the findings, Ellsworth Air Force Base has implemented a number of strategies for increased recovery of recyclables from its solid waste streams.Originality/valueQuantifying missed opportunities for recycling is a useful action in planning future recycling operations aimed at best solid waste management practices.

Relationship of Compressibility Parameters to Municipal Solid Waste Decomposition

Recently, there has been substantial interest in the enhancement of refuse decomposition in landfills, which results in increased settlement. In this paper, changes in waste compressibility as a function of the state of decomposition are reported. Samples representative of residential refuse were decomposed under conditions designed to simulate decomposition in both control and bioreactor landfills. Twenty four one-dimensional oedometer tests (63.5 mm cell) were performed on refuse prepared in laboratory-scale reactors for measurement of primary (Cc) and secondary (Cαi, representing creep, and Cβi, representing biological) compression indices. The state of decomposition was quantified by the methane yield and the cellulose (C) plus hemicellulose (H) to lignin (L) ratio. The magnitude of compressibility was shown to increase as refuse decomposed and compressibility parameters were correlated with the state of decomposition. Initial settlement increased with decreasing (C+H)/L ratio while the creep index was fairly independent of the state of decomposition. The coefficients of primary compression (Cc) for bioreactor samples showed an increasing trend with decreasing (C+H)/L ratios. Cc increased from 0.16 to 0.36 as (C+H)/L decreased from 1.29 to 0.25, and similar values of Cc were obtained with control samples at similar (C+H)/L ratios. The creep index range was estimated at 0.02–0.03 for control and bioreactor samples in various states of decomposition. The magnitude of the biological degradation index (Cβi) depended on the degradation phase with the highest value of 0.19 obtained during the phase of accelerated methane production. Proposing a single Cc for landfill settlement calculations may lead to inaccurate predictions. Properties of each waste sublayer will change as a function of the decomposition stage, and dominating processes with appropriate compressibility parameters should be applied to individual sublayers.

Urban residential refuse composition and generation rates for the 20th century.

Examination of historical data shows that 3.5 x 10(8) tonnes (t) of residential refuse was discarded in New York City (NYC) during the 20th century. Maximum and minimum rates of per capita mass discard of residential refuse during this time are reported in 1940 (940 kg per capita yr(-1)) and 1961, 1963 (320 kg per capita yr(-1)), respectively. Since 1980, per capita residential refuse discard rates have been steady and comparatively low (430 kg per capita yr(-1) +/- 2.5%). Fuel ash accounted for approximately 34% of residential refuse in NYC during the century. A decline of refuse bulk density (as collected) from approximately 500 to 200 kg m(-3) and an increase in refuse organic matter content from 20% to 80% (by mass) is reported between 1920 and 1990 and is due largely to mass fraction reductions forfuel ash and increases for paper and plastic. Approximately 4.9 x 10(8) t of refuse was disposed in NYC during the 20th century (including commercial and residential refuse), representing a total pool of about 8.0 x 10(7) t of organic carbon (as C) that has entered city landfills and incinerators.

The Influence of Contract Design on Contractor Performance: The Case of Residential Refuse Collection

The Influence of Contract Design on Contractor Performance: The Case of Residential Refuse Collection

Production of non-methane organic compounds during refuse decomposition in a laboratory-scale landfill

The presence of non-methane organic compounds (NMOCs) in landfill gas is well documented. However, there is little understanding of the degree to which the production of NMOCs should be attributed to the volatilization of household hazardous waste as opposed to intermediates of the anaerobic decomposition of the major cellulosic components of municipal solid waste. The objectives of this study were: (1) to compare the NMOC yields for decomposed refuse, fresh residential refuse, and a synthetic refuse; and (2) to evaluate the source of NMOCs emitted during refuse decomposition. Replicate 2-1 reactors were filled with shredded residential refuse expected to contain household hazardous waste, synthetic refuse containing no hazardous constituents, and control reactors with decomposed refuse only. Anaerobic decomposition of each refuse was initiated with a seed of decomposed refuse, and the reported methane and NMOC yields were corrected for that attributable to the seed. The NMOC yields from the seed, synthetic refuse, and residential refuse were comparable (0.62 to 1.01 X 10-4 g NMOC (dry g)-1, suggesting that the volatilization of hazardous organic compounds is not the sole source of NMOCs in landfill gas and that anaerobic biodegradation intermediates also contribute to NMOCs.

Characterization of Canadian Backyard Composts: Chemical and Spectroscopic Analyses

Despite the growing interest in backyard composting as a means to reduce residential refuse at source, there has been little study of its chemical nature and state of maturity. We obtained samples of mature compost from backyard sources in Newfoundland, Ontario and British Columbia, Canada, as well as raw input and immature compost from one BC municipal source. Chemical analysis indicated that composting was effective, proceeding with loss of C, decrease in C:N ratio, increase in pH to near neutrality, and high available N and P. Contents of heavy metals were low. Solution 31P nuclear magnetic resonance (NMR) spectroscopy of extracts showed a high proportion of orthophosphate P, indicating vigorous microbial activity and high P availability. Solid state 13C NMR with cross-polarization and magic angle spinning (CPMAS NMR) of whole composts showed that decomposition proceeds to some extent with increasing ratio of alkyl to O-alkyl C, as observed in many studies of organic soils, forest floor and composts of low substrate quality. However, the backyard operations also produced much more peak broadening, and a marked tendency for increase of carboxyl C. These also indicate vigorous biological activity. The chemical and spectroscopic analyses confirm traditional knowledge of the efficacy of backyard composting, and suggest that it is a worthwhile object of research.

An analysis of residential sanitation collection pricing under alternative delivery arrangements

This paper investigates residential sanitation collection (RSC) pricing under two different service delivery arrangements: (1) the municipal RSC arrangement where municipal employees collect residential refuse, and (2) the contract RSC arrangement where private sector firms, under contract with a municipality, collect residential refuse. The results of the study indicate that municipal RSC prices are significantly higher than contract RSC prices. Furthermore, municipal RSC prices exhibit greater variability than contract RSC prices. These findings suggest that contract pricing is consistent with pricing in a competitive market.

Cultivation Intensity and Residential Site Structure: An Ethnoarchaeological Examination of Peasant Agriculture in the Sierra de los Tuxtlas, Veracruz, Mexico

Agricultural and residential space were integrated in prehistoric lowland Mesoamerica for productive and domestic activities to produce distinctive patterns of settlement and land use visible in the archaeological record. Ethnoarchaeological studies provide information on the behavioral component of site formation in such contexts. Contemporary residential refuse treatment and the use of infield agricultural land are examined here from a sample of farming households in the Sierra de los Tuxtlas of southern Veracruz, Mexico. A model of site structure (the House-Lot model) relates the maintenance of refuse-free (clear area) and refuse-laden (intermediate area) spaces within the house lot to household farming activities outside of the residential lot. Variation in the intensity of cultivation on infield plots is shown to correlate with variability in the size of areas within house lots. This research suggests that the distribution of prehistoric residential debris might be used to diagnose factors of ancient agriculture and settlement in contexts commonly encountered during archaeological excavation and survey.

Private versus Public Provision of Refuse Removal Service

The debate over public versus private provision of community services has been extensive since Ronald Reagan became President. However, more empirical evidence, especially regarding citizen satisfaction, is needed before the broad policy question can be addressed effectively. Refuse collection is one service provided by the private sector in several communities. This study compares citizen satisfaction with public and private provision of residential refuse removal service in one metropolitan area of the United States.

Equity in financing local services: The case of residential refuse

The paper is a review of theoretical and empirical arguments on equity considerations in the application of user charges to finance one public service, residential refuse collection and disposal. The main question examined is whether, and in what circumstances, user charges have sufficiently objectionable effects on equity as to offset their efficiency advantages. The effects of user charges and of the alternative, taxation, on both horizontal equity and vertical equity are discussed. A number of empirical studies are examined. The considerable shortcomings of available studies are emphasized. It is concluded that user charges have clear advantages over taxation for horizontal equity, and the vertical equity effects are probably not important enough to offset the horizontal equity and the efficiency advantages. However, special circumstances in a specific locality may warrant a different conclusion.

A Pilot Program in Automated Residential Refuse Collection

A Pilot Program in Automated Residential Refuse Collection

How Much Do Government Services Really Cost?

Great efforts are being made to increase productivity and to reduce costs of government services. A necessary starting point is adequate knowledge of the true cost of service. The field of residential refuse collection is investigated and empirical evidence is presented that (1) cities do not know the cost of services provided by municipal agencies; (2) city budgets substantially understate the actual cost of service. Reasons why such under- reporting occurs are examined. Because city officials perceive program costs to be lower than they really are, they are often unable to evaluate alternatives and therefore they fail to take advantage of opportunities to increase efficiency.