Off-Site Lime Stabilisation as an Option to Treat Pit Latrine Faecal Sludge for Emergency and Existing On-Site Sanitation Systems

Off-site lime stabilisation for treating faecal sludge was assessed by undertaking small-scale (35 L) and large-scale (600 L) field trials in Blantyre, Malawi. Hydrated lime was dosed to maintain pH 10, pH 10.5, pH 11, pH 11.5, and pH 12 depending on the buffer capacity of the faecal sludge in the four replica small-scale field trials. Significant reduction of E. coli to below the detection limit of 104 CFU/100 mL within 1 hour of treatment was reported for pH > 11. Based on the small-scale findings, large-scale field trials were conducted and greater than 3 log removal of E. coli was observed under pH 12 conditions. Therefore, based on the study, off-site lime stabilisation by dosing lime in the range of 10–35% w/w (dry solid basis), depending on the buffer capacity and solids content of the sludge to maintain pH > 11, can be used to sanitise faecal sludge during emergencies, as well as for existing on-site sanitation systems.

Chromium Distribution and Spatial Variations in the Finer Sediment Grain Size Fraction and Unfractioned Surficial Sediments on Nyanza Gulf, of Lake Victoria (East Africa)

Surficial sediments collected from the Nyanza Gulf of Lake Victoria (East Africa) were used to determine spatial concentrations of Cr and determine differences in contents of the unfractioned (whole sediment) and the finer grain size sediments, establishing any changes in Cr enrichment and potential ecological risks using sediment quality guidelines. A single pollution index was also used to evaluate level of Cr contamination. The spatial mean Cr contents in the <63 µm (silt-clay) fraction were found to be significantly lower than those in the unfractioned sediments, but with a strong linear positive correlation. The study results show decreasing spatial amounts of Cr in surficial sediments of the Nyanza Gulf, when compared to a study done 20 years earlier. However, the 95% confidence limits of the overall mean Cr in unfractioned sediments exceed the threshold effect concentration (TEC), indicating the potential for Cr remobilization from sediments. In general the sediment enrichment is evidence of possible dominance of lithogenous sources of Cr in the surface lake sediments, with potential anthropogenic sources from the drainage system and nearshore urban areas. The sediments are unpolluted with respect to geoaccumulation index, and sediment enrichment factors suggest a minor to moderate enrichment of Cr in surficial sediments of three sites around the Nyanza Gulf zones and around the river mouth in the main lake.

Green Concrete from Sustainable Recycled Coarse Aggregates: Mechanical and Durability Properties

Present investigations deal with the development of green concrete (M 30 grade) using recycled coarse aggregates for sustainable development. Characterization of recycled coarse aggregates showed that physical and mechanical properties are of inferior quality and improvement in properties was observed after washing due to removal of old weak mortar adhered on its surface. The influence of natural coarse aggregates replacement (50 and 100%) with recycled coarse aggregate on various mechanical and durability properties of hardened concrete were discussed and compared with controls at different w/c ratio. Improvements in all the engineering properties of hardened concrete were observed using washed recycled coarse aggregates. The compressive strength of 28-day hardened concrete containing 100% washed recycled aggregate was slightly lower (7%) than concrete prepared with natural aggregates. Water absorption, carbonation, and rapid chloride penetration test were conducted to assess the durability of the concrete. Concrete was found moderately permeable for chloride ions penetration and no carbonation was observed in all the concrete mixes studied.

Modeling the Sorption of Ni2+ and Co2+ on Saprist Peat Using the Response Surface Methodology

A detailed study of the sorption of Ni2+ and Co2+ from simulated wastewater on saprist peat is presented. The significantly decomposed peat possessed a strong sorptive capacity that was maintained over a wide range of pH. With a metal concentration range of 50 to 200 mg/L, pH range of 3 to 10, peat dose of 2 to 40 g/L, and contact time of 12 to 24 h, batch experiments were conducted based on a four-factor Box-Behnken response surface design. The percentage removals of Ni2+ and Co2+ were analyzed using analysis of variance. Second order response surface models were developed with the significant factors and their interactions to predict the percentage sorption of Ni2+ and Co2+ independently. The prediction equations were verified with additional data not used in developing the equations. The study showed that the saprist peat could be a potential industrial metal adsorbent and the percentage of uptake of Ni2+ and Co2+ could be accurately predicted using the second order response surface models developed. Ni2+ uptake was greater for the two metals and reached a maximum value at just below a neutral pH and Co2+ uptake continued to increase from pH > 5, with higher uptake percentage at pH 10.

Intraurban Analysis of Domestic Solid Waste Disposal Methods in a Sub-Sahara African City

The study examined the influence of socioeconomic attributes of residents on domestic solid waste disposal methods in Lagos metropolis, Nigeria. Primary data for the study were obtained through questionnaire administered on residents in Eti-Osa, Ikeja, and Mushin Local Government Areas (LGAs) representing the low, medium, and high densities, respectively, into which the sixteen LGAs in Lagos metropolis were stratified. One out of every four wards in each LGA was selected for survey. From a total of 15,275 residential buildings in the ten wards, one out of every forty buildings (2.5%) was selected using systematic random sampling where a household head was sampled. Information obtained includes the residential characteristics and the disposal methods. Enquiries into the socioeconomic attributes of the residents showed that 59.9% were high income earners and 76.6% had attained tertiary school education. This study concluded that six disposal methods were common in the study area. Furthermore, through multinomial logistic regression, the influence of socioeconomic characteristics of residents (density, income, age of respondents, educational status, and length of stay) on domestic solid waste disposal methods varied significantly in Lagos metropolis. The study established that most of the solid waste disposal methods utilized by residents in Lagos metropolis were not environment-friendly.

Solid Waste Management Practices in the Informal Sector of Gweru, Zimbabwe

This paper contributes to the debate on the role of the informal sector in solid waste management by examining the effectiveness of informal sector solid waste management practices in transforming waste into nonwaste in the city of Gweru in Zimbabwe. The study focused on 589 informal enterprises that were surveys using questionnaire interviews and focus group discussions with key informants. Analysis of solid waste management in the informal sector of Gweru has revealed that large amounts of waste are generated indicating poor material efficiency in the enterprises, especially in food market areas where huge amounts of biodegradable material and vegetable wastes are generated and disposed of haphazardly. Analysis of the key factors that include solid waste generation rates, collection frequencies and transportation, waste minimisation, and reduction practices showed that the current waste management system is unsustainable in the long run. The municipality of Gweru needs to provide more resources for financing, training, and manpower to enable effective provision of an environmentally friendly solid waste management system in the city, including the informal sector.

Waste Management Strategies in an Urban Setting Example from the Tamale Metropolis, Ghana

Tamale, one of the fastest growing cities in Ghana, is faced with daunting challenges in the management of Municipal Solid Waste. A corresponding increase of population and rising quality of life with high rates of resource consumption patterns have led to serious problems of high volumes of waste generated and costs involved. This research was therefore designed to focus on the Municipal Solid Waste Management strategies in Tamale, seeking to assess the performance of newly introduced tricycles for waste collection. The study employed the methodology of administration of questionnaire and interviews. The questionnaire and interviews revealed that there is a relationship in the level of education and how households stored their waste before disposal. There is also a close relationship in the household income level (residential class) and the use of covered plastic waste bins. Most households rated waste collection after the introduction of the tricycle as good followed by very good and satisfactory whilst none were of the view that waste collection was not good. Though there has been an improvement in waste collection after the introduction of the tricycles, there is the need for an integrated approach to waste management where all aspects of waste management are analyzed.

Overview of the WEEE Directive and Its Implementation in the Nordic Countries: National Realisations and Best Practices

Electronic devices and mobile applications have become a part of everyday life. Fast technological progress and rapid product obsolescence have led to the rapid growth of waste electrical and electronic equipment (WEEE). Due to hazardous substances and also substantial amounts of valuable materials contained in electrical and electronic equipment, the European Union has implemented Directives related to WEEE, in order to reduce negative environmental and health impacts and to improve material recovery of valuable substances from WEEE. This paper provides an overview of the WEEE Directive and its implementation to national legislations in Finland, Sweden, and Norway and, further, describes how the nationwide WEEE recovery infrastructures in the Nordic countries have been built. The Nordic WEEE management systems are evaluated from the point of resource efficiency and best practices. Evidently, the WEEE management systems as established in the Nordic countries have advantages because the WEEE collection rates in 2012 were 12 kg/inhab./year, in Finland, 16 kg/inhab./year, in Sweden, and 27 kg/ inhab./year, in Norway, despite their sparsely populated nature. The Swedish and Norwegian experiences, especially, with long history of WEEE recovery indicate that increasing consumer awareness leads to more environmentally sound behaviour and improves recovery efficiency.

e-Waste Management Scenarios in Malaysia

e-Waste, or electronic waste, disposal that is uncontrolled can be harmful to human health and the environment because e-waste contains toxic substances and heavy metals. However, if the waste is properly managed, it can become a business opportunity that produces high returns because e-waste also contains valuable materials, such as gold, silver, platinum, and palladium. The government of Malaysia wants to ensure the safe, effective, and economically beneficial management of e-waste in Malaysia. Management approaches have included law enforcement and regulation and the promotion of e-waste recovery activities. e-Waste of no commercial value must be disposed of at sites/premises licensed by the Department of Environment (DOE), Malaysia. To date, 18 full recovery facilities and 128 partial recovery facilities that use various available technologies have been designated for the segregation, dismantling, and treatment of e-waste. However, there are issues faced by the recovery facilities in achieving the goal of converting e-waste into a source material. The issues include the e-waste supply, the importation of e-waste derived products and coding, and finally the need to develop the criteria for e-waste processing technologies to ensure the safety and the sustainability of the facilities.

Response Surfaces for Fresh and Hardened Properties of Concrete with E-Waste (HIPS)

The fresh and hardened properties of concrete with E-waste plastic, that is, high impact polystyrene (HIPS), as a partial replacement for coarse aggregate were analyzed using response surface methodology (RSM). Face-centred central composite response surface design was used in this study. The statistical models were developed between the factors (HIPS and water cement ratio) and their response variables (slump, fresh density, dry density, compressive strength, spilt tensile strength, and flexural strength). The Design-Expert 9.0.3 software package was used to analyze the experimental values. The relationships were established and final mathematical models in terms of coded factors from predicted responses were developed. The effects of factors on properties for all variables were seen visually from the response surface and contour plot. Validation of experiments has shown that the experimental value closely agreed with the predicted value, which validates the calculated response surface models with desirability = 1. The HIPS replacement influenced all the properties of concrete than water cement ratio. Even though all properties show the decline trend, the experimented values and predicted values give a hope that the E-waste plastic (HIPS) can be used as coarse aggregate up to certain percentage of replacement in concrete which successively reduces the hazardous solid waste problem and conserves the natural resources from exhaustion.