The welfare implications of safe water and sanitation cannot be overstated. The economic gains from provision of improved services to millions of unserved Africans in enormous. The international ...adoption of Millennium Development Goals brought the inadequacies of service provision sharply into focus. With only 58% and 31% enjoying access to water and sanitation services respectively, Sub-Saharan Africa is the only continent that is off-track in achieving the MDGs in 2015. The problem is compounded by the fact that a rigorous and credible baseline did not exist on coverage to improved water and sanitation and resources required to meet the MDGs. This book aims to contribute to this gap by collecting a wealth of primary and secondary information to present the most up-to-date and comprehensive quantitative snapshot of water and sanitation sectors. The book evaluates the challenges to the water and sanitation sectors within the urban and rural areas and deepen our understanding of drivers of coverage expansion in the context of financing, institutional reforms, and efficiency improvements. Finally, the book establishes the investment needs for water and sanitation with a target of meeting the MDGs and compares with the existing financing envelopes, disaggregated by proportions that can be recouped by efficiency gains and net financing gaps. The directions for the future draw on lessons learned from best practices and present the menu of choices available to African countries. There is no recipe book that neatly lays out the possible steps the country should adopt to enhance coverage and quality of service. The challenges differ to a significant extent among African countries and solutions must be tailored to individual national or regional conditions.
Plastics are contaminants of emerging concern that can enter the environment from multiple sources, including via land application of treated sewage sludge (biosolids). Biosolids samples collected ...from 82 wastewater treatment plants (WWTPs) across Australia and covering 34% of the population during census week in 2016 were quantitatively analyzed to estimate the release of seven common plastics. Quantitative analysis was performed by pressurized liquid extraction followed by double-shot microfurnace pyrolysis coupled to gas chromatography mass spectrometry. Ninety nine percent of the samples contained plastics (Σ6plastics) at concentrations of between 0.4 and 23.5 mg/g dry weight (median; 10.4 mg/g dry weight), while polycarbonate was not detected in any sample. Per-capita mass loads of plastics (Σ6plastics) released were between 8 and 877 g/person/year across all investigated WWTPs. Polyethylene was the predominant plastic detected, contributing to 69% of Σ6plastics. Based on the concentrations measured, it was projected that around 4700 metric tons (Mt) of plastics are released into the Australian environment through biosolids end-use each year, equating to approximately 200 g/person/year, which represents 0.13% of total plastics use in Australia. Of this, 3700 Mt of plastics are released to agricultural lands and 140 Mt to landscape topsoil. Our results provide a first quantitative per-capita mass loads and emission estimate of plastic types through biosolids end-use.
Sewage treatment works and stormwater outfalls were identified as sources of microplastics in the Victoria Harbor, Hong Kong. Local treated sewage and stormwater effluents contained up to 10,816 ...pieces per m3 of microplastics, mainly polyethylene (PE) and polypropylene (PP), being discharged at an average rate of 3.5 mg per capita daily. Bioaccumulation of microplastics in marine fish collected from the vicinity of the effluent discharge outfalls was also studied. The temporal variations of microplastics in terms of abundance, shape and polymer type in fish were found consistent with those in the effluents and surface water. The abundance of microplastics was significantly higher in March 2017 (dry season). Microplastics in fish were predominantly in fiber form and identified as PE and PP. The observed temporal variations suggest uptake of microplastics by fish from the treated sewage and stormwater effluents.
Display omitted
•Microplastics (MPs) are abundant in sewage and stormwater effluents in Hong Kong and peak in March.•Similar temporal patterns of MPs were confirmed in surface seawater and fish.•Polyethylene and polypropylene were the predominant MPs found.•Fish near to discharges was found moderately contaminated with MPs.•Amount of microplastics found in fish positively correlated with the sizes of fish.
Microplastics that are contained in household dust, personal care products, and other factors, are discharged into sewage treatment facilities (STF). While these microplastics are treated at the STF ...with a high treatment efficiency through settling, precipitation, filtering, and other treatments, considering the large amount of effluent, large quantities of microplastics are still discharged into marine environments. In this study, biological STF using the anaerobic-anoxic-aerobic (A2O), sequence batch reactor (SBR), and the Media processes were investigated to confirm the efficiency of these treatments and the associated amounts of microplastics released for each process. The three investigated processes were found to have treatment efficiencies of about 98% or more. However, due to the large amount of effluent, more than four billion pieces of microplastic were released each year in each facility. Thus, even though biological STF show high treatment efficiencies, substantially large amounts of microplastics are still released into the marine environment.
•Sewage treatment facilities are one of the sources of microplastics.•Each facility was found to have treatment efficiencies of about 98% or more.•More than three billion microplastics per year were released from the each facility.•The tire fragments seem to inflow through the combined sewerage.
The need to apply innovative technologies for maximizing the efficiency and minimizing the carbon footprint of sewage treatment plants has upgraded sewage sludge management to a highly sophisticated ...research and development sector. Sewage sludge cannot be regarded solely as 'waste'; it is a renewable resource for energy and material recovery. From this perspective, legislation on sewage sludge management tends to incorporate issues related to environmental protection, public health, climate change impacts and socio-economic benefits. This paper reviews the existing legislative frameworks and policies on sewage sludge management in various countries, highlighting the common ground as well as the different priorities in all cases studied. More specifically, the key features of legislation regarding sludge management in developed countries such as the USA, Japan, Australia, New Zealand and the European Union (EU27) are discussed.
Coral reefs are in decline worldwide, and land‐derived sources of pollution, including sewage, are a major force driving that deterioration. This review presents evidence that sewage discharge occurs ...in waters surrounding at least 104 of 112 reef geographies. Studies often refer to sewage as a single stressor. However, we show that it is more accurately characterized as a multiple stressor. Many of the individual agents found within sewage, specifically freshwater, inorganic nutrients, pathogens, endocrine disrupters, suspended solids, sediments, and heavy metals, can severely impair coral growth and/or reproduction. These components of sewage may interact with each other to create as‐yet poorly understood synergisms (e.g., nutrients facilitate pathogen growth), and escalate impacts of other, non‐sewage–based stressors. Surprisingly few published studies have examined impacts of sewage in the field, but those that have suggest negative effects on coral reefs. Because sewage discharge proximal to sensitive coral reefs is widespread across the tropics, it is imperative for coral reef–focused institutions to increase investment in threat‐abatement strategies for mitigating sewage pollution.
This book addresses the "last frontier" in liquid systems treatment by documenting and examining the methods currently in use. Driven by the industry's increasing need to determine how grit can be ...better characterized, modeled, and reliably removed, this book is a first step toward understanding the implications of the methods selected and allowing for proper design and optimization of grit removal systems.
Discharge of treated sewage leads to release of antibiotic resistant bacteria, resistance genes and antibiotic residues to the environment. However, it is unclear whether increased abundance of ...antibiotic resistance genes in sewage and sewage-impacted environments is due to on-site selection pressure by residual antibiotics, or is simply a result of fecal contamination with resistant bacteria. Here we analyze relative resistance gene abundance and accompanying extent of fecal pollution in publicly available metagenomic data, using crAssphage sequences as a marker of human fecal contamination (crAssphage is a bacteriophage that is exceptionally abundant in, and specific to, human feces). We find that the presence of resistance genes can largely be explained by fecal pollution, with no clear signs of selection in the environment, with the exception of environments polluted by very high levels of antibiotics from manufacturing, where selection is evident. Our results demonstrate the necessity to take into account fecal pollution levels to avoid making erroneous assumptions regarding environmental selection of antibiotic resistance.
PDF
