Summary The Western Treatment Plant, a major sewage treatment plant west of Melbourne, Australia, is widely regarded as a significant conservation site for waterbirds. But experiences from various parts of the world suggest that sewage can also be hazardous to waterbirds, and has probably been responsible for mass-kill events. The intent of this contribution is to raise awareness about the potential for adverse impacts of sewage treatment plants on waterbirds, and to stimulate debate on the issue, with the ultimate objective of developing appropriate management strategies to mitigate the risk of mass kills. 相似文献
AIMS: To determine the fate of the enteric indicator organism, Escherichia coli, in sewage sludge (biosolids)-amended agricultural soil in relation to soil type and moisture status under controlled conditions. METHODS AND RESULTS: We enumerated Escherichia coli in soil by membrane filtration and most probable number techniques. The background concentration of E. coli was higher in sandy loam than in silty clay soil. E. coli numbers increased in soil following addition of dewatered, mesophilic anaerobically digested sludge. Escherichia coli declined to a small extent with time in both moist and air-dried unamended control soils, although decay was only highly significant (P < 0.001) in moist sandy loam (T(90) = 100 days). Removal rates were high in sludge-treated moist soil (T(90) = 20 days), but were significantly reduced in amended air-dried soil. CONCLUSIONS: Slow removal of E. coli in air-dried soil as against their rapid decay in moist soil after sludge application indicated that the soil biota are involved in pathogen reduction processes in sludge-amended soil. SIGNIFICANCE AND IMPACT OF THE STUDY: Soil ecological mechanisms are implicated as having a critical role in the fate of enteric organisms introduced into temperate agricultural soil in sewage sludge. 相似文献
This study examines the co-digestion of intermediate landfill leachate and sewage sludge from a municipal wastewater treatment plant. Application of leachate as a co-fermentation component increased the concentrations of soluble organic compounds (expressed as total organic carbon), ammonium nitrogen, and alkalinity in the digester influents.The biogas yield obtained from the co-fermentation of a 20:1 sewage sludge: intermediate leachate mixture was 1.30 m3 per kg of removed volatile solids (VS), while that from a 10:1 mixture was 1.24 m3 per kg of removed VS. These values exceeded the biogas yield for the sludge alone by 13% and 8%, respectively. The leachate addition influenced the proportion of methane to a minor extent. Increased methane yields of 16.9% and 6.2% per kg of removed VS were found for the two sewage sluge:intermediate leachate mixtures, respectively. 相似文献
The main aim of this study was to examine the influence of soil properties on the leaching of Cd, Cr, Cu, Ni, Pb, and Zn following the application of polluted sewage sludge to contrasting topsoils. Seventy agricultural soil samples from different parts of Spain were amended with a single dose of sewage sludge (equivalent to 50 t dry weight ha?1) and a column study was performed under controlled conditions. After two, four, and six months of incubation, 283 ml of distilled water (equivalent to a rainfall event of 25 l m?2) was applied. The leachates were then collected and analyzed for metals. For all of the soils considered, the pH was the most important parameter for the control of mobility metals (except for Cu, determined by the sand and soil organic carbon and only to a lesser extent by the soil pH r2 = 0.604, p < 0.001) and was negatively related to all of the studied metals. For Pb and Zn, soil pH was the single soil property explaining their mobility (r2 = 0.411, p < 0.001 for Pb; r2 = 0.713, p < 0.001 for Zn) while for Cd, Cr and Ni, EC, sand and silt also appeared in the statistical models (r2 = 0.753, p < 0.001 for Cd; r2 = 0.366, p < 0.001 for Cr; r2 = 0.784, p < 0.001 for Ni). In the basic soils, soil texture was the most important soil property controlling the mobility of metals (except for that of Pb, which it only weakly predicted). For the acidic-neutral soils, the soil pH was the most important soil property controlling metal mobility (except for that of Cr, which was mainly determined by the pseudo-total Cr content). 相似文献
Dry and wet sludge samples were collected from the sewage sludge storage site and primary treatment ponds at As-Samra Wastewater Treatment Ponds in Al Hayshmia, Jordan. The concentrations of polynuclear aromatic hydrocarbons (PAH) and macro- and microelements were determined using gas chromatography-mass spectrometry (GC-MS) and inductively coupled plasma-mass spectrometry (ICP-MS), respectively.
Environmentally relevant concentrations of PAH were detected ranging from 62 μg g?1 to 70 μg g?1 for dry sludge and from 35 μg g?1 to 47 μg g?1 for wet sludge. These results indicated a potential environmental risk if sewage sludge is reused in Jordan as organic fertilizer without first being treated. The results of the study showed that the sewage sludge samples were contaminated with low levels of heavy metals, as the dry sludge samples were characterized by higher concentrations of most analyzed elements than for wet sludge samples. Still, none of the trace metal concentrations exceeded the threshold concentration levels for agricultural-related sludge.
Unlike many other nutrients found in sludge, the Total Organic Carbon (TOC%) found in dry and wet sludge revealed similar values, at 13.18 percent and 13.29 percent, respectively. The total phosphorus ranged from 0.25% for dry sludge to 0.47% for wet sludge. Total nitrogen varied from 0.80% for wet sludge to 1.01% for the dry sludge samples. The overall nutrients levels are close to those found in the literature. The findings of this study have improved the understanding of sewage sludge characteristics in a semiarid environment. 相似文献
Biosolids, also known as sewage sludge, are reusable organic materials separated from sewage during treatment. They can be managed in a variety of ways. Different options for biosolids handling in Sydney, Australia, are compared in this study using life-cycle assessment. Two key comparisons are made: of system scenarios (scenario 1 is local dewatering and lime amendment; scenario 2 is a centralized drying system) and of technologies (thermal drying versus lime amendment). The environmental issues addressed are energy consumption, global warming potential (GWP), and human toxicity potential (HTP). Scenario 2 would consume 24% more energy than scenario 1. This is due to the additional electricity for pumping and particularly the petrochemical methane that supplements biogas in the drier. A centralized system using the same technologies as scenario 1 has approximately the same impacts. The GWP and HTP of the different scenarios do not differ significantly. The assessment of technology choices shows significant differences. The ample supply of endogenous biogas at North Head sewage treatment plant for the drying option allows reductions, relative to the lime-amendment option, of 68% in energy consumption, 45% in GWP, and 23% in HTP. Technology choices have more significant influence on the environmental profile of biosolids processing than does the choice of system configurations. Controlling variables for environmental improvement are the selection of biogas fuel, avoidance of coalsourced electrical energy, minimization of trucking distances, and raising the solids content of biosolids products. 相似文献