The environmental and biosecurity characteristics of livestock carcass disposal methods: A review

Livestock mortalities represent a major waste stream within agriculture. Many different methods are used throughout the world to dispose of these mortalities; however within the European Union (EU) disposal options are limited by stringent legislation. The legal disposal options currently available to EU farmers (primarily rendering and incineration) are frequently negatively perceived on both practical and economic grounds. In this review, we assess the potential environment impacts and biosecurity risks associated with each of the main options used for disposal of livestock mortalities in the world and critically evaluate the justification for current EU regulations. Overall, we conclude that while current legislation intends to minimise the potential for on-farm pollution and the spread of infectious diseases (e.g. transmissible spongiform encephalopathies, bacterial pathogens), alternative technologies (e.g. bioreduction, anaerobic digestion) may provide a more cost-effective, practical and biosecure mechanism for carcass disposal as well as having a lower environmental footprint. Further social, environmental and economic research is therefore warranted to assess the holistic benefits of alternative approaches for carcass disposal in Europe, with an aim to provide policy-makers with robust knowledge to make informed decisions on future legislation.     

Survival of selected pathogens in diluted sludge of a thermophilic waste treatment plant and in NaCl-solution under aerobic and anaerobic conditions

Decimal reduction times (DRT or D-value) of Campylobacter jejuni, Salmonella enterica (formerly Salmonella choleraesuis) serovar Senftenberg, Escherichia coli, and Listeria monocytogenes were determined in two different matrices, diluted fermenter sludge (DFS) and 0.95% NaCl-solution (NaCl) at 50 degrees C, both under aerobic and anaerobic conditions. Depending on aeration, matrix composition, and the respective organism, the D-values varied between 10min and more than 15h. Generally the viability of bacteria decreased faster in DFS compared to NaCl-solution and under aerobic compared to anaerobic conditions. After 24h no viable cells could be detected in DFS, both under aerobic as well as under anaerobic conditions, whereas viable cells were still found in NaCl solutions. In both matrices the detection limits determined by means of PCR-based and classical microbiological methods were compared and pointed to lower detection limits of the latter methods. Results of the present investigation show that test organisms were far from surviving several days in DFS whereas hydraulic retention times normally used for thermophilic anaerobic digestion are in the range of 2 weeks. However, an underestimation of survival rates of the test organisms seems probable when applying aerobic standard methods.     

Identification of novel eubacteria from spent mushroom compost (SMC) waste by DNA sequence typing: ecological considerations of disposal on agricultural land

A small study was undertaken to examine the microbiological characteristics of spent mushroom compost (SMC), which is the major waste by-product of the mushroom industry and which is regularly disposed off by application to agricultural land. The primary aim of this study was to examine SMC for the presence of faecal bacterial pathogens, including Campylobacter spp., Salmonella spp. and Listeria monocytogenes. Secondly it was desirable to quantify bacterial and fungal populations within SMC, and also qualitatively identify the diversity of bacterial populations within SMC, through employment of rDNA PCR and direct sequencing techniques on the culturable microflora. Conventional microbiological analyses of SMC material (n=30) from six commercial operations in both Northern Ireland and the Republic of Ireland, failed to detect Salmonella spp, Listeria spp. or Campylobacter spp. in any of the SMC material examined. Total aerobic plate counts gave a mean count of log10 7.01 colony forming units (cfu) per gram SMC material (range: log10 6.53-7.52 cfu/g). Fungal counts gave a mean count of log(10) 4.57 cfu per gram SMC material (range: log10 3.93-4.98 cfu/g). From a total of greater than 50 colony picks, a total of 12 bacterial morphotypes were identified and were further examined by employment of partial 16S rRNA gene amplification and sequencing techniques, yielding several genera and species, including Bacillus licheniformis, Bacillus subtilis, Klebsiella/Enterobacter sp. Microbacterium sp. Paenibacillus lentimorbus, Pseudomonas mevalonii, Sphingobacterium multivorum and Stenotrophomonas sp. This is the first preliminary report on the microbial diversity of SMC waste and demonstrates the presence of several species that have not been previously described in SMC, in addition to two potentially novel species within the genera Microbacterium and Stenotrophomonas. It is thereby important to examine the ecological microbe-microbe and plant-microbe interactions that are occurring between the native bacterial soil flora and those added annually (theoretically estimated at approximately 10(18) cells) through the application of SMC. Such studies would be beneficial in helping to ascertain the ecological consequences involved in the disposal of SMC waste on agricultural land.     

Environmental impact assessment of sprayed-on asbestos in buildings

This study evaluated the environmental impacts of sprayed-on asbestos, which had been used as insulation material in buildings, from multiple perspectives, mainly at the disposal stage. The health risks from asbestos emission and energy consumption were estimated. Two disposal scenarios were assumed for the asbestos: melting for reduced-risk disposal and ordinary packaging/landfilling. We estimated the asbestos emission and health risk in the case of packaging/landfilling, assuming uncontrolled management of the landfill site. A difficulty with introducing health-risk concepts into life cycle assessment (LCA) is the pulse–flux problem, which is discussed in the light of these estimations. In order to solve this problem, we proposed a method using a conversion factor representing exposure-dose/emission, and showed that emission could be converted into health risk. We also estimated the energy consumption for melting asbestos in the disposal stage, which can decrease the health risk. If we consider the energy consumption for the life cycle of asbestos, only a little energy is required for melting, compared with the large amount of energy saved in the use stage owing to the insulating effect of the asbestos. The trade-off relationship between health risk and energy consumption for the disposal scenarios indicated the need for weighting methods to handle trade-offs such as this. Received: July 2, 1998 / Accepted: December 20, 1999     

An investigation of the presence of methane and other gases at the Uzundere-Izmir solid waste disposal site, Izmir, Turkey

Izmir is a large metropolitan city with a population of 3,114,860. The city consists of 27 townships, each township has a population of not less than 10,000 inhabitants. The two major solid waste disposal sites are in the townships of Uzundere and Harmandali. The amount of solid waste that is disposed at each of these sites is about 800 and 1800 t/day, respectively. In Uzundere, compost is produced from the organic fraction of urban solid wastes while the residual material is deposited at a disposal site with a remaining capacity of 700,000 m(3) as of 2001. Gas monitoring and measurements were carried out at the disposal site in Uzundere. For this purpose, nine sampling wells were drilled on selected locations. Each well was furnished with perforated metal pipes suitable for gas monitoring and measurements. The following gases were monitored: O(2), CH(4), CO, CO(2), and H(2)S. The most important finding was that the concentrations of CH(4) in the wells ranged from 7 to 57%. Dilution of the CH(4) by O(2) down to the LEL levels (5-15%) is always possible and poses a continuing risk at the site. Furthermore, the levels of O(2) require that access to the site be limited to only authorized personnel.     

Factors controlling pathogen destruction during anaerobic digestion of biowastes

Anaerobic digestion is the principal method of stabilising biosolids from urban wastewater treatment in the UK, and it also has application for the treatment of other types of biowaste. Increasing awareness of the potential risks to human and animal health from environmental sources of pathogens has focused attention on the efficacy of waste treatment processes at destroying pathogenic microorganisms in biowastes recycled to agricultural land. The degree of disinfection achieved by a particular anaerobic digester is influenced by a variety of interacting operational variables and conditions, which can often deviate from the ideal. Experimental investigations demonstrate that Escherichia coli and Salmonella spp. are not damaged by mesophilic temperatures, whereas rapid inactivation occurs by thermophilic digestion. A hydraulic, biokinetic and thermodynamic model of pathogen inactivation during anaerobic digestion showed that a 2 log10 reduction in E. coli (the minimum removal required for agricultural use of conventionally treated biosolids) is likely to challenge most conventional mesophilic digesters, unless strict maintenance and management practices are adopted to minimise dead zones and by-pass flow. Efficient mixing and organic matter stabilisation are the main factors controlling the rate of inactivation under mesophilic conditions and not a direct effect of temperature per se on pathogenic organisms.     

Nitrous oxide (N2O) emissions from waste and biomass to energy plants.

Following the Kyoto protocol with respect to reducing emissions of greenhouse gases emissions, and EU energy policy and sustainability in waste management, there has been an increased interest in the reduction of emissions from waste disposal operations. From the point of view of nitrous oxide (N2O) emissions, waste incineration and waste co-combustion are very acceptable methods for waste disposal. In order to achieve very low N2O emissions from waste incineration, particularly for waste with higher nitrogen content (e.g. sewage sludge), two factors are important: temperature of incineration over 900 degrees C and avoiding the selective non-catalytic reduction (SNCR) de-NO(X) method based on urea or ammonia treatments. The more modern selective catalytic reduction (SCR) systems for de-NO(X) give rise to negligible sources of N2O.     

Extricating Membership as a PRP at Hazardous Waste Disposal Sites

Corporations often become potentially responsible parties (PRPs) at hazardous waste sites because of their past transportation or disposal of hazardous substances at such sites. Determining a PRP's potential liability for the assessment and cleanup of hazardous waste sites is a challenging effort and often results in disputes among other PRPs regarding appropriate allocation of response action costs to each party. Further, public companies have an obligation to report probable and reasonably estimable costs under Generally Accepted Accounting Principles (GAAP) for environmental liabilities at their current or prior hazardous waste sites. The first step in such an evaluation is to determine whether or not a PRP can extricate themselves from any association with the subject site or, alternatively, demonstrate de minimis status. This article describes the methods by which PRPs can extricate themselves from liability associated with response action costs at contaminated sites, including: evaluating a PRP's prior settlements or indemnifications with other PRPs; identifying insurance coverage or other financial assurance instruments for the disposal facility; and examining applicable statutes of limitations against when a PRP received notification from the regulatory agency. The article also presents a case study discussing how a PRP with a portfolio of 72 hazardous waste disposal sites was able to extricate itself from the majority of these sites, resulting in only four sites where the PRP was determined to be a PRP and where an associated allocable share was assigned. © 2014 Wiley Periodicals, Inc.     

Comparison of LLW Disposal Facilities at Major Department of Energy Sites

Near surface disposal facility design and management are examined and compared using a systems approach that defines facility performance as a function of three components (or subsystems): the disposal facility design (cover systems and bottom liners); the properties of the waste (waste composition, waste form and waste package); and the site‐specific environmental features (climate, geology, and hydrology). We report an evaluation of five DOE near surface disposal facility case studies, selected to provide a “representative” sample that included disposal sites with a range of waste and environmental characteristics across the DOE. The facilities selected were the Savannah River E‐Area Engineered Trenches, Hanford Integrated Disposal Facility, Idaho Radioactive Waste Management Complex, Oak Ridge Environmental Management Waste Management Facility, and Nevada National Security Site Area 5. ©2015 Wiley Periodicals, Inc.     

Genotoxicity of leachates from highly polluted lowland river sediments destined for disposal in landfill

The Matanza-Riachuelo is one of the most polluted rivers of Latin America. The complex chemical mixture of pollutants discharged into the river is accumulated in the river sediments. In this paper, Matanza-Riachuelo river sediment composition and genotoxicity were tested in order to develop a cost-effective, environmentally sound option for disposal and management of contaminated dredged materials. Sampling was performed in a rural area, in a solid waste dumpsite and also in an urban and industrial area. The concentrations of total heavy metals increased from the upper basin to the lower basin. The Ames Salmonella typhimurium test and the Saccharomyces cerevisiae D7 test were performed using toxicity characteristic leachate procedure (TCLP) leachates. The concentrations of copper, lead, and chromium in the leachates exceeded the guide levels for the protection of aquatic life. Low concentrations of organic chlorinated compounds were detected in the leachates. Genotoxic profiles were obtained by testing TCLP leachates from polluted sediment samples with Salmonella typhimurium, Saccharomyces cerevisiae D7, and water sediment suspension with Allium cepa test. No mutagenicity effects on Ames test were observed. Gene conversion and mitotic reversion in Saccharomyces cerevisiae D7 and chromosome aberration in Allium cepa were induced by the sediment samples. Results obtained suggest that dredged sediments could be classified as genotoxic hazardous waste.     

Reducing acid leaching of manganiferous ore: effect of the iron removal operation on solid waste disposal

The process of reducing acid leaching of manganiferous ore is aimed at the extraction of manganese from low grade manganese ores. This work is focused on the iron removal operation. The following items have been considered in order to investigate the effect of the main operating conditions on solid waste disposal and on the process costs: (i) type and quantity of the base agent used for iron precipitation, (ii) effective need of leaching waste separation prior to the iron removal operation, (iii) presence of a second leaching stage with the roasted ore, which might also act as a preliminary iron removal step, and (iv) effect of tailings washing on the solid waste classification. Different base compounds have been tested, including CaO, CaCO3, NaOH, and Na2CO3. The latter gave the best results concerning both the precipitation process kinetics and the reagent consumption. The filtration of the liquor leach prior to iron removal was not necessary, implying significant savings in capital costs. A reduction of chemical consumption and an increase of manganese concentration in the solution were obtained by introducing secondary leaching tests with the previously roasted ore; this additional step was introduced without a significant decrease of global manganese extraction yield. Finally, toxicity characteristic leaching procedure (TCLP) tests carried out on the leaching solid waste showed: (i) a reduction of arsenic mobility in the presence of iron precipitates, and (ii) the need for a washing step in order to produce a waste that is classifiable as not dangerous, taking into consideration the existing Environmental National Laws.     

CH4 and N2O from mechanically turned windrow and vermicomposting systems following in-vessel pre-treatment

Methane (CH4) and nitrous oxide (N2O) are included in the six greenhouse gases listed in the Kyoto protocol that require emission reduction. To meet reduced emission targets, governments need to first quantify their contribution to global warming. Composting has been identified as an important source of CH4 and N2O. With increasing divergence of biodegradable waste from landfill into the composting sector, it is important to quantify emissions of CH4 and N2O from all forms of composting and from all stages. This study focuses on the final phase of a two stage composting process and compares the generation and emission of CH4 and N2O associated with two differing composting methods: mechanically turned windrow and vermicomposting. The first stage was in-vessel pre-treatment. Source-segregated household waste was first pre-composted for seven days using an in-vessel system. The second stage of composting involved forming half of the pre-composted material into a windrow and applying half to vermicomposting beds. The duration of this stage was 85 days and CH4 and N2O emissions were monitored throughout for both systems. Waste samples were regularly subjected to respirometry analysis and both processes were found to be equally effective at stabilising the organic matter content. The mechanically turned windrow system was characterised by emissions of CH4 and to a much lesser extent N2O. However, the vermicomposting system emitted significant fluxes of N2O and only trace amounts of CH4. In-vessel pre-treatment removed considerable amounts of available C and N prior to the second stage of composting. This had the effect of reducing emissions of CH4 and N2O from the second stage compared to emissions from fresh waste found in other studies. The characteristics of each of the two composting processes are discussed in detail. Very different mechanisms for emission of CH4 and N2O are proposed for each system. For the windrow system, development of anaerobic zones were thought to be responsible for CH4 release. High N2O emission rates from vermicomposting were ascribed to strongly nitrifying conditions in the processing beds combined with the presence of de-nitrifying bacteria within the worm gut.     

Landfills in Jiangsu province, China, and potential threats for public health: leachate appraisal and spatial analysis using geographic information system and remote sensing

Waste disposal is of growing environmental and public health concern in China where landfilling is the predominant method of disposal. The assessment of potential health hazards posed by existing landfills requires sound information, and processing of a significant amount of spatial data. Geographical information system (GIS) and remote sensing (RS) are valuable tools for assessing health impacts due to landfills. The aims of this study were: (i) to analyze the leachate and gas emissions from landfills used for domestic waste disposal in a metropolitan area of Jiangsu province, China, (ii) to investigate remotely-sensed environmental features in close proximity to landfills, and (iii) to evaluate the compliance of their location and leachate quality with the relevant national regulations. We randomly selected five landfills in the metropolitan areas of Wuxi and Suzhou city, Jiangsu province, established a GIS database and examined whether data were in compliance with national environmental and public health regulations. The leachates of the sampled landfills contained heavy metals (Pb, As, Cr(6+) and Hg) and organic compounds in concentrations considered harmful to human health. Measured methane concentrations on landfill surfaces were low. Spatial analysis of the location of landfills with regard to distance from major water bodies, sensible infrastructure and environmental conditions according to current national legislation resulted in the rejection of four of the five sites as inappropriate for landfills. Our results call for rigorous evaluation of the spatial location of landfills in China that must take into consideration environmental and public health criteria.     

Geotechnical quality assurance of construction of disposal facilities

This paper summarizes the technical resource document of the same name (U.S. EPA-600/S2-84-040, March 1984). Although the technical resource document is specifically addressed to the construction of hazardous waste disposal facilities within the U.S.A., most of the topics discussed and most of the general suggestions made are of universal applicability. The need for a quality assurance programme as a management practice which assures the protection of the human health and environment is discussed within the framework of the EPA regulations promulgated on 26 July 1982. The permittee of a hazardous waste disposal facility is shown to be somewhat unique in the construction industry given the three responsibilities, design, construction and operations, and quality assurance, all consolidated with him. The geotechnical parameters which should be tested, observed and documented during the construction, operation and closure of a disposal facility are identified. The limitations of design properties tests and the applicability of index properties tests are discussed. A summarized statistical analysis of sampling size, frequency and distribution to support a hazardous waste disposal facility quality assurance programme is presented. Accepted and commonly used methods for testing water content, unit weight, specific gravity, grain-size distribution, liquid limit, plastic limit, cohesive soil consistency, water content/density/compactive effort, cohesionless soil relative density, and geomembranes/geotextiles are identified. The criteria for the selection of a particular test method are discussed. A quality assurance programme, suitable for the somewhat unique permittee of a hazardous waste disposal facility, is presented. Considerations for such a quality assurance programme are also addressed.     

Use of recycled plastic in concrete: a review

Numerous waste materials are generated from manufacturing processes, service industries and municipal solid wastes. The increasing awareness about the environment has tremendously contributed to the concerns related with disposal of the generated wastes. Solid waste management is one of the major environmental concerns in the world. With the scarcity of space for landfilling and due to its ever increasing cost, waste utilization has become an attractive alternative to disposal. Research is being carried out on the utilization of waste products in concrete. Such waste products include discarded tires, plastic, glass, steel, burnt foundry sand, and coal combustion by-products (CCBs). Each of these waste products has provided a specific effect on the properties of fresh and hardened concrete. The use of waste products in concrete not only makes it economical, but also helps in reducing disposal problems. Reuse of bulky wastes is considered the best environmental alternative for solving the problem of disposal. One such waste is plastic, which could be used in various applications. However, efforts have also been made to explore its use in concrete/asphalt concrete. The development of new construction materials using recycled plastics is important to both the construction and the plastic recycling industries. This paper presents a detailed review about waste and recycled plastics, waste management options, and research published on the effect of recycled plastic on the fresh and hardened properties of concrete. The effect of recycled and waste plastic on bulk density, air content, workability, compressive strength, splitting tensile strength, modulus of elasticity, impact resistance, permeability, and abrasion resistance is discussed in this paper.     

Medical wastes management in the south of Brazil

Medical (clinical) wastes are costly in disposal and carry risks of infection, or physical injury, and of exposure to potentially harmful pharmaceuticals, as well as being aesthetically unacceptable. Technological advances in disposal, together with the introduction of rigorous emission standards for incinerators and similarly stringent control standards for non-burn “alternate” disposal technologies, continue to drive improvements in waste management. Are these improvements attainable in developing countries?Where adequate resources and a robust infrastructure are lacking, investment in advanced disposal technologies may be counterproductive. Developments must be appropriate to and manageable by the communities served; sustainable low-technology approaches may be preferable. There remains a need for affordable technical innovation, as well as underlying political support and international financial and technical assistance, to sustain meaningful improvements in waste management in remote and isolated regions and more generally in developing countries.     

Application of a Proposed Generic LLW Waste Package Analysis With Changing Infiltration in a Humid Environment

Corrosion of carbon steel boxes filled with low‐level radioactive waste and buried within a near surface disposal facility in a humid environment was evaluated using an integrated systems approach framework. The time to hydraulic failure from initial burial to development of holes through the wall of a given waste package from pitting corrosion was calculated for four corrosion scenarios under two different corrosion cases. The two corrosion cases chosen were a constant rate of corrosion and a slowing rate of corrosion. Corrosion rates were estimated for carbon steel buried in soil from several historical studies and related to the corrosivity and aeration profile of the soil. The scenarios were chosen to represent a range of possible conditions at current and future U.S. Department of Energy disposal facilities. For each scenario, once the time to hydraulic failure had been estimated, the amount of liquid present in each waste package at the time of failure was calculated as an estimate of leachate available for subsurface transport. The Savannah River E‐Area Engineered Trench was used as a basis for the hypothetical disposal facility. © 2016 Wiley Periodicals, Inc.     

An analytic network process model for municipal solid waste disposal options

The aim of this paper is to present an evaluation method that can aid decision makers in a local civic body to prioritize and select appropriate municipal solid waste disposal methods. We introduce a hierarchical network (hiernet) decision structure and apply the analytic network process (ANP) super-matrix approach to measure the relative desirability of disposal alternatives using value judgments as the input of the various stakeholders. ANP is a flexible analytical program that enables decision makers to find the best possible solution to complex problems by breaking down a problem into a systematic network of inter-relationships among the various levels and attributes. This method therefore may not only aid in selecting the best alternative but also helps decision makers to understand why an alternative is preferred over the other options.     

Cost‐Effective Sediment Dredge Disposal Options for Small Craft Harbors in Canada

Sediment dredge disposal options were reviewed to improve cost‐effectiveness and environmental safety for dredging of coastal sediments at the Department of Fisheries and Oceans Small Craft Harbours (DFO‐SCH) program in Canada. Historically, contaminated dredge sediments exceeding federal guidelines were disposed of in nearby landfills. Recent federal regulatory changes in sediment quality guidelines adopted by provincial regulators in Canada has resulted in updates to guidelines for disposal of contaminated solids in landfills. Updates now require specific and general disposal options for contaminated dredge material destined for land‐based disposal, resulting in more expensive disposal in containment cells (if contaminated sediments exceed federal guidelines). However, as part of this study, a leachate testing method was applied to contaminated sediments to simulate migration of potential contaminants in groundwater. Using this approach, leachate quality was compared to federal freshwater criteria and drinking water quality guidelines for compliance with new regulations. Leachate testing performed on the highest sediment contaminant concentrations triggered less than 2 percent potable water exceedances, meaning that most dredge spoils could be disposed of in privately owned or provincially operated landfill sites, providing less expensive disposal options compared to containment cell disposal. Current dredge disposal practices were reviewed at 35 harbor sites across Nova Scotia and their limitations identified in a gap analysis. Improved site management was developed following this review and consultation with interested marine stakeholders. New disposal options and chemical analyses were proposed, along with improvements to cost efficiencies for management of dredged marine sediments in Atlantic Canada. © 2013 Wiley Periodicals, Inc.     

Medical waste management in Jordan: a study at the King Hussein Medical Center

As in many other developing countries, the generation of regulated medical waste (RMW) in Jordan has increased significantly over the last few decades. Despite the serious impacts of RMW on humans and the environment, only minor attention has been directed to its proper handling and disposal. This study was conducted in the form of a case study at one of Jordan's leading medical centers, namely, the King Hussein Medical Center (KHMC). Its purpose was to report on the current status of medical waste management at KHMC and propose possible measures to improve it. In general, it was found that the center's administration was reasonably aware of the importance of medical waste management and practiced some of the measures to adequately handle waste generated at the center. However, it was also found that significant voids were present that need to be addressed in the future including efficient segregation, the use of coded and colored bags, better handling and transfer means, and better monitoring and tracking techniques, as well as the need for training and awareness programs for the personnel.