Capability of the Invasive Tree Prosopis glandulosa Torr. to Remediate Soil Treated with Sewage Sludge

Sewage sludge improves agricultural soil and plant growth, but there are hazards associated with its use, including high metal(loid) contents. An experimental study was conducted under greenhouse conditions to examine the effects of sewage sludge on growth of the invasive tree Prosopis glandulosa, as well as to determine its phytoremediation capacity. Plants were established and grown for seven months along a gradient of sewage sludge content. Plant traits, soil properties, and plant and soil concentrations of N, P, K, Cd, Pb, Cu, Ni, Zn, Cr, Co, As, and Fe were recorded. The addition of sewage sludge led to a significant decrease in soil pH, and Ni, Co, and As concentrations, as well as an increase in soil organic matter and the concentrations of N, P, Cu, Zn, and Cr. Increasing sewage sludge content in the growth medium raised the total uptake of most metals by P. glandulosa plants due to higher biomass accumulation (taller plants with more leaves) and higher metal concentrations in the plant tissues. P. glandulosa concentrated more Cd, Pb, Cu, Zn, and Fe in its below-ground biomass (BGB) than in its above-ground biomass (AGB). P. glandulosa concentrated Ni, Co, and As in both BGB and AGB. P. glandulosa has potential as a biotool for the phytoremediation of sewage sludges and sewage-amended soils in arid and semi-arid environments, with a potential accumulation capability for As in plant leaves

Will improving wastewater treatment impact shorebirds? Effects of sewage discharges on estuarine invertebrates and birds

Human communities often discharge wastewaters into estuaries, influencing their organic and pollutant loading, benthic community and trophic structure. The implementation of the Water Framework Directive has encouraged the treatment of wastewater discharges across European estuaries, but the implications for invertebrate and waterbird communities are poorly understood. We explore the effects of untreated sewage discharges on the distribution and abundance of foraging black-tailed godwits Limosa limosa and their main benthic prey (bivalves and polychaetes) on the Tejo estuary in Portugal, a major European Special Protection Area with ongoing wastewater improvements. Patches of mudflat in close proximity to sewage streams (70 m), and godwits foraging in these areas can attain the highest intake rates recorded for the estuary. However, high intake rates can also be attained on bivalve prey, and bivalve biomass and density increase slightly with distance from sewage streams. As the organic input from sewage outfalls influences invertebrate abundance and godwit foraging rates over relatively small areas, the ongoing implementation of a sewage treatment network on the Tejo estuary seems likely to have only a limited impact on the wintering godwit population. The localized effect of untreated sewage discharges on benthic communities suggests that the implications for predatory birds are relatively minor where alternative prey are available, but may be more severe in locations with more depauperate, polychaete-dominated invertebrate communities

Heavy metal content of vegetables irrigated with mixtures of wastewater and sewage sludge in Zimbabwe: Implications for human health

There is growing public concern in Zimbabwe over the illegal cultivation of vegetables on soils amended with sewage sludge or irrigated with admixtures of sewage and sewage sludge. Excessive accumulation of heavy metals in agricultural soils may not only result in environmental contamination, but lead to elevated heavy metal uptake by crops, which may affect food quality and safety. The work reported here studied heavy metal concentrations in crops irrigated with sewage sludge and sewage/sewage sludge admixtures at Firle Municipal Farm in Harare. The crops analysed in this study are heavily contaminated with the four regulated elements Cd, Cu, Pb and Zn. This contamination is at its highest in two of the staple dietary crops maize and tsunga. Tsunga leaves contained 3.68 mg kg-1 Cd, over 18 times the permissible level by the EU standards (0.2 mg kg-1); Cu concentrations were 111 mg kg-1, 5 times the EU Standard (20 mg kg-1); concentrations of Pb were 6.77 mg kg-1, over 22 times the permissible levels allowed by both EU standards and UK guidelines (0.3 mg kg-1); Zn concentrations were 221 mg kg-1, over 4 times the guideline value (50 mg kg-1). The other plants (beans, maize, peppers and sugarcane) also contained concentrations of heavy metals above the permissible levels. Furthermore the concentrations observed in this study were higher than those reported by other workers who have examined vegetation from other contaminated sites. This study highlights the potential risks involved in the cultivation and consumption of vegetables on plots irrigated with sewage sludge, a practice which may place at risk the health of the urban population who consume these vegetables

Treatment and removal strategies for estrogens from wastewater

Natural and synthetic steroidal estrogens (estrone, 17β-estradiol and 17α-ethinylestradiol) are endocrine disrupters, that are discharged consistently from the sewage treatment works into surface waters, thereby causing endocrine disrupting effects to aquatic organisms at trace concentrations (nanogram per litre). Several years of research have been focused on their fate, behaviour and removal in the environment but primarily in the sewage treatment works which acts as a sink for these compounds. This review attempts to summarize the factors involved in the removal of these chemicals from the sewage treatment works. Biological processes, and to a limited extent physio-chemical properties, play a vital role in the endocrinal deactivation of which these compounds. The efficiency of these processes is highly dependent on operating parameters (such as sludge retention time, redox potential, etc) that govern the secondary treatment process of a functional sewage treatment works. Although advanced treatment technologies are available, cost and operational considerations do not make them a sustainable solution

Remote sensing operations (multispectral scanner and photographic) in the New York Bight, 22 September 1975

Ocean dumping of waste materials is a significant environmental concern in the New York Bight. One of these waste materials, sewage sludge, was monitored in an experiment conducted in the New York Bight on September 22, 1975. Remote sensing over controlled sewage sludge dumping included an 11-band multispectral scanner, fiver multispectral cameras and one mapping camera. Concurrent in situ water samples were taken and acoustical measurements were made of the sewage sludge plumes. Data were obtained for sewage sludge plumes resulting from line (moving barge) and spot (stationary barge) dumps. Multiple aircraft overpasses were made to evaluate temporal effects on the plume signature

A note on sewage sludge - risk assessments and fertilization value

A number of recent studies of risk related to agricultural use of sewage sludge are reviewed, as a contribution to the discussion of potential for use in organic agriculture. Furthermore a very tentative assessment of the fertilization value of sewage sludge and its derived products is developed

The state of sewage system economics in rural areas in Poland

Infrastructure is the basis of economic activities both in urban and in rural areas. It is also one of main conditions for improving quality of life. Among its most important elements are: water delivery system, as well as sewage treatment network and sewage treatment plants. These devices should create one composite techno-economical system. Non-integrated water delivery contributes to bigger waste of water, and without connection to integrated sewage treatment systems, it can be a serious threat to the environment In Poland, and in rural areas particularly, this situation is highly unsatisfactory. In 2007, share of population connected to water network in rural areas was 73.3%, while for sewage network is was only 21.3%. In many communes, this share was even less than 10%. One can mention a few reasons of this state, mainly: lack of sufficient investment for 40 years after the 2nd World War, big water deficit in rural areas (brought about by droughts and thus, big reduction or decline of water level in shallow homestead wells, being a main water source), big dispersion of rural settlements in the country, limiting economies of scale achievement, and lack of resources available for local authorities. The latter, having not enough resources for infrastructure development, made a decisions to concentrate on water system firstly, while more costly waste management was treated as a second-tier need. In consequence, bigger investment in this field has just started since the half of nineties in the 20th century. Despite this late investment, in December 2007 one could observe that the total length of sewage network was still 4 times shorter than water network. Only 15.5% of rural administrative units were canalized. A quantity of household wastewater purified was 5 times smaller than a quantity of water used. There was also a small number of household sewage treatment plants (figure 4), which can be a good response for dispersed rural settlements. Thus, cesspools (many of them leaking), remain the main way of wastewater collection, being a serious threat for environment. However, there is a hope that this situation will change during next 7 10 years, mainly by obliging Poland to follow the EU Directive 91/271/EEC. This law expects any European Union member state to create, till the end of 2015,more than 2 thousand inhabitants. In Polish National Sewage Treatment Program, almost 1600 administrative units of these kind, were indentified. 1400 of them are totally or partially inhabited by rural community. Releasing this program is, however, determined strongly by local self-government activity and its ability to gain sufficient financial resources for this purpose

Laboratory measurements of radiance and reflectance spectra of dilute primary-treated sewage sludge

The feasibility of remotely monitoring ocean dumping of waste products such as acid and sewage sludge is evaluated. The laboratory arrangement, solar simulator, and test results from three experiments conducted in the laboratory are described. Radiance and reflectance spectra are presented for primary-treated sewage sludge mixed with two types of base water. Results indicate that upwelled reflectance varies in a near-linear manner with concentration and that the sludge has a practically flat signal response between 420 and 970 nm. Well-defined upwelled reflectance spectra were obtained for the sewage-sludge mixtures at all wavelengths and concentrations. The spectral-reflectance values appeared to be influenced by the type of base water, but this influence was small, especially for the mixtures with low concentrations of sewage sludge

Practical application of ferrate(VI) for water and wastewater treatment: site study’s approach

This paper presents the work aiming to validate the practical feasibility of ferrate(VI) used as an alternative to the existing coagulant (e.g., ferric chloride/sulphate) for both drinking water and domestic sewage treatment via series of pilot plant trials. For drinking water treatment, a ferrate(VI) dose of 0.1 mg/L can achieve 93% and 97% particle removal (in terms of particle counting) after the filtration for raw water and for the ozonized water, respectively, which is satisfied to the treated water quality requirement for the particles’ removal. Moreover, ferrate(VI) can remove 10% metformin, benzotriazole and acesulfam from raw water but FeCl3 with ozonation can’t. When treating domestic sewage at pilot scale trials, ferrate(VI) demonstrated encouraging performance as well, at a very lower dose range, 0.1–0.2 mg Fe/L, ferrate(VI) achieved better performance in comparison with high dosed ferric sulphate. This will reduce chemical demand and sludge production and therefore results in a low operating cost and generates substantial cost saving in treating sewage. Keywords: BOD removal, Coagulation, COD removal, Drinking water treatment, Ferrate(VI), Micro pollutant reduction, Particle removal, Phosphorous removal, Sewage treatmen

Laboratory measurements of radiance and reflectance spectra of dilute secondary-treated sewage sludge

The National Aeronautics and Space Administration (NASA), in cooperation with the Environmental Protection Agency (EPA) and the National Oceanic and Atmospheric Administration (NOAA), conducted a research program to evaluate the feasibility of remotely monitoring ocean dumping of waste products such as acid and sewage sludge. One aspect of the research program involved the measurements of upwelled spectral signatures for sewage-sludge mixtures of different concentrations in an 11600-liter tank. This paper describes the laboratory arrangement and presents radiance and reflectance spectra in the visible and near-infrared ranges for concentrations ranging from 9.7 to 180 ppm of secondary-treated sewage sludge mixed with two types of base water. Results indicate that upwelled radiance varies in a near-linear manner with concentration and that the sludge has a practically flat signal response between 420 and 970 nm. Reflectance spectra were obtained for the sewage-sludge mixtures at all wavelengths and concentrations