Relation of waste generation and composition to socio-economic factors: a case study

To develop an effective waste management strategy for a given region, it is important to know the amount of waste generated and the composition of the waste stream. Past research has shown that the amount of waste generated is proportional to the population and the average mean living standards or the average income of the people. In addition, other factors may affect the amount and composition of waste. These are climate, living habits, level of education, religious and cultural beliefs, and social and public attitudes. This paper presents the findings of a study carried out in a suburban municipal area in Sri Lanka to determine the solid waste generation rate and waste composition based on field surveys and to determine the related socio-economic factors. A database was developed that included information on the quantity and composition of waste generated in a sample of households in the study area over a time period. The collected data was analysed to relate waste generation and composition data to various socio-economic factors. Over 400 sample households were selected for the study using a stratified random sampling methodology based on municipal wards and property values. A technique that considers both the number of households in a particular income group (property value range) and the standard deviation of property values within a given income group was used to determine the appropriate sample size for each municipal ward. Through category and regression analyses, the quantities of waste and waste composition were related to several socio-economic factors. The paper describes the basis for the sample selection, the methodology adopted for data collection, the socio-economic parameters used for the analysis, and the relationships developed from the analysis.     

生物滤池对气相与液相中污染物质的净化

通过实验室研究探讨了生物滤池同时处理废水和废气的可行性。试验结果表明：在２５℃－３７℃条件下,甲苯废气的流量为９０Ｌ／ｈ,甲苯浓度为５００ｍｇ／ｍ＾３;废水的流量为０．４Ｌ／ｈ,ＣＯＤｃｒ浓度为４００－７５０ｍｇ／Ｌ,甲苯与ＣＯＤｃｒ的去除率分别是７０％－７２％和８６％－８９％。     

生活垃圾与危险废物焚烧二噁英类排放特征研究

对某省52家焚烧企业(21家生活垃圾和31家危险废物)排放烟气数据进行了分析,结果表明,两类焚烧企业二噁英类17种单体分布有所不同,生活垃圾焚烧烟气中浓度较高的是O8CDD和O8CDF;危险废物焚烧烟气中较大的是2,3,4,7,8-P5CDF、2,3,7,8-T4CDD和1,2,3,7,8-P5CDD;两类焚烧企业二噁英类单体对I-TEQ贡献最高的都是2,3,4,7,8-P5CDF,贡献率分别为0. 7%～45%和10%～67%;两者的17种二噁英类与I-TEQ的相关性分析表明,1,2,3,7,8-P5CDF在2类焚烧炉中与I-TEQ均存在较高的相关性,其相关系数分别0. 932和0. 927,可以作为潜在的测定指示物。     

On causes of illegal waste dumping in Slovakia

This paper examines the determinants of illegal waste dumping at the county level in Slovakia (in 77 of 79 counties), using a truncated regression model. It analyzes a unique data-set composed of illegal dumping data provided by the TrashOut platform and sociodemographic data from the national statistical authority.

This study shows that a higher level of expected overall waste production results in a higher rate of illegally dumped waste and a higher number of illegal dumping sites. More precisely, income has a positive impact on the rate of illegal waste dumping, poverty influences the rate of illegal dumping negatively and a higher level of education does not result in more responsible waste management. On the contrary, higher education has a positive influence on the rate of dumping. A negative relationship between costs of illegal waste disposal and dumping rate, as well as a positive relationship between costs of legal waste disposal and dumping rate has been revealed.     

The determination and matching analysis of pinch point temperature difference in evaporator and condenser of organic rankine cycle for mixed working fluid

Exergo-economic analysis of the pinch point temperature difference (PPTD) in both evaporator and condenser of sub-critical organic Rankine cycle system (ORCs) are performed based on the first and second laws of thermodynamics. Taking mixture R13I1/R601a as a working fluid and the annual total cost per net output power Z as exergo-economic performance evaluation criterion, the effects of PPTD in evaporator ΔT_e, and the PPTD ratio of condenser to evaporator y, on the exergo-economic performance of ORCs are analyzed. Moreover, how some other parameters influence the optimal PPTD in evaporator ΔT_e,opt and the optimal PPTD ratio of condenser to evaporator y_opt are also discussed. It has been found that the exergo-economic performance of ORCs is remarkably influenced by ΔT_e and y, and there exists ΔT_e,opt and y_opt. In addition, ΔT_e,opt and y_opt are affected by heat transfer coefficient ratio of condenser to evaporator ß, the temperature of working fluid at dew point in condenser T_1a, and composition of R13I1/R601a: larger ß and T_1a lead to lower ΔT_e,opt and y_opt; by contraries, larger mass fraction of R13I1 makes ΔT_e,opt and y_opt increase, and y_opt increases linearly. The effects of the temperature of working fluid at bubble point in evaporator T_3a, mass flow rate of exhaust flue gas m_g, and inlet temperature of exhaust flue gas T_gi on ΔT_e,opt and y_opt are very slight. For comparison, three additional working fluids, namely R601a, R245fa, and 0.32R245fa/0.68R601a, are also taken into account.     

Household food waste: the implications of consumer choice in food from purchase to disposal

Food and food-related waste is a high priority in terms of waste minimisation in New Zealand. Over the summer of 2012–2013, a survey of 147 participants was conducted on a range of views and practices related to environmental challenges and understandings. The survey, undertaken in Palmerston North, New Zealand, captured a wide socio-demographic. This article focuses on respondents’ food practices from purchase, to plate, to disposal and the environmental implications of these practices. The survey data have allowed an enriched understanding of both individual and structural level challenges as well as incentives towards improving environmental practices in relation to household food waste minimisation. The results indicated that, in keeping with other research in this area, food waste increases according to the number of individuals in a household, and in particular the number of younger people. Also, while the majority of participants were at least “somewhat concerned” about their households’ environmental impact, over three quarters of participant households put food waste into their rubbish bin. Some solutions and directions to further progress research, policy, and practice in this area are offered, and include the need for more direct and personalised communication regarding waste minimisation, along with the provision of kerbside food waste collections. It is clear that individual- or household-level changes are important and must be supported systemically by both local body and state level legislation and initiatives, if there is to be any substantial decline in food waste going to landfill.     

Experimental investigation of a 250-kW turbine organic Rankine cycle system for low-grade waste heat recovery

An organic Rankine cycle (ORC) is generally used for converting low-grade heat into electricity. In this study, an extensive literature survey was conducted to identify current research gaps on experimental ORC systems. Specifically, there is limited experimental data and limited details on thermal and expander efficiencies of ORC systems. In order to address these gaps, the objective of this study included developing a turbine ORC with a power output exceeding 50 kW and thermal efficiency exceeding 8% for a heat source temperature < 120°C. The experimental results indicated that the system achieved a net power output of 242.5 kW and a thermal efficiency of 8.3% (the highest value for a turbine ORC system for the heat source temperature below 120°C). Thus, the study addressed the gaps identified in the research area of ORCs.     

Biogas production from pistachio (Pistaciavera L.) de-hulling waste

Pistachio processing wastes create significant waste management problems unless properly managed. However, there are not well-established methods to manage the waste generated during the processing of pistachios. Anaerobic digestion can be an attractive option not only for the management of pistachio processing wastes but also producing renewable energy in the form of biogas. This study investigated anaerobic digestibility and biogas production potential of pistachio de-hulling waste from wet de-hulling process. Best to our knowledge, this is the first report on biogas production from pistachio de-hulling waste. The results indicated that (1) anaerobic digestion of pistachio de-hulling wastewater, solid waste, and their mixtures in different ratios is possible with varying levels of performance; (2) 1 L of de-hulling wastewater (chemical oxygen demand concentration of 30 g/L) produced 0.7 L of methane; (3) 1 L of de-hulling wastewater and 20 g of pistachio de-hulling solid waste produced 1.25 L of methane; and (4) 1 g of de-hulling solid waste produced 62.6 mL of methane (or 134 mL of biogas).     

固体废物全过程管理中固体废物鉴别研究

对固体废物应进行全过程管理,固体废物鉴别是固体废物全过程管理的基础和关键,包括依据产生来源鉴别和过程鉴别两种方法,依据产生来源鉴别包括丧失原有利用价值的物质、在生产过程中产生的副产物、环境治理和污染控制过程中产生的物质、其他物质四类,在每一类中详细地列举了属于该产生来源的具体固体废物种类名称,便于理解和增强可操作性。过程鉴别包括在固体废物再生利用过程和处置过程中的固体废物鉴别两类,其中在再生利用过程的固体废物鉴别中明确指出了固体废物再生利用产物只有同时满足产品质量标准要求、国家污染控制标准要求以及有实际市场需求、固定用户等条件时,才不作为固体废物管理,在处置过程的固体废物鉴别中具体地列出了处置固体废物全过程中仍然作为固体废物管理的国际惯用处置方式。同时,给出了清晰的"原料—产品—固体废物—处置或产品"全过程中固体废物的产生节点和相应的固体废物类别图,为固体废物鉴别工作提供参考,使固体废物全过程管理有的放矢,有效防止固体废物对环境和人体健康造成的危害。     

Politics of distributive justice in the siting of waste disposal facilities: the case of Tokyo

Distributive justice is a crucial aspect of disputes over locally unwanted land uses. This study examines the rise and fall in influence of a particular idea of distributive justice that originated in the 23 wards of Tokyo in the early 1970s – namely, that each of the wards should be required to dispose of its own waste within the ward. This idea – in-ward waste disposal (IWWD) – was adopted as a significant principle in waste facility siting plans, but its influence rose and fell over time until the idea was finally abandoned in 2003. Critically reviewing ideational approaches in political studies, the causes and mechanisms behind the changes in IWWD’s influence are elucidated. The result shows the importance of considering multiple, different types of variables and examining the interaction between them to explain the prominence of an idea and its change over time.