Extraction and purification of phosphorus from the ashes of incinerated biological sewage sludge

Phosphorus depletion represents a significant problem. Ash of incinerated biological sewage sludge (BSS) contains P, but the presence of heavy metals (e.g., Fe and Al) is the main issue. Based on chemical characterization by SEM-EDS, ED-XRF and ICP-OES techniques, the characteristics and P content of bottom ash (BA) and fly ash (FA) of incinerated BSS were very similar. On BA, P extraction carried out in counter-current with an S:L ratio of 1:10 and H2SO4 0.5 M led to better extraction yields than those of a similar test with H2SO4 1 M and an S:L ratio of 1:5 (93% vs. 86%). Comparing yields with H2SO4 0.5 M (S:L ratio of 1:10), the counter-current method gave better results than those of the crossflow method (93% vs. 83.9%), also improving the performance obtained with HCl in crossflow (93% vs. 89.3%). The results suggest that the purification of the acid extract from heavy metals with pH variation was impractical due to metal precipitation as phosphates. Extraction with H2SO4 and subsequent treatment with isoamyl alcohol represented the best option to extract and purify P, leading to 81% extraction yields of P with low amounts of metals

Evaluating Global Municipal Solid Waste Management Efficiency from A Circular Economy Point of View

The Circular Economy (CE) principles recently set out by the European Union (EU) include additional guidelines for municipal solid waste (MSW) management. More detailed information about material streams must be generated and managed so that the entire system can be monitored from a new perspective. Suitable indicators (and indices from them) must be made readily available, so that they can be used to assess the efficiency that the European Union expects from the sector. This article presents a preliminary critical analysis of the literature and identifies that indicators and indices should be considered to facilitate the evaluation of MSW management under a CE vision. The analysis is combined with a discussion of the situation in various countries, to provide an overview of attempts to implement CE strategies worldwide. Special waste is not dealt with in this article as EU updated the vision of waste management starting from the MSW sector, on which this work is focused. © 2021 WITPress. All rights reserved.This research was supported by Act 211 Government of the Russian Federation, contract № 02.A03.21.0006

What's New Is Old: Resolving the Identity of Leptothrix ochracea Using Single Cell Genomics, Pyrosequencing and FISH

Leptothrix ochracea is a common inhabitant of freshwater iron seeps and iron-rich wetlands. Its defining characteristic is copious production of extracellular sheaths encrusted with iron oxyhydroxides. Surprisingly, over 90% of these sheaths are empty, hence, what appears to be an abundant population of iron-oxidizing bacteria, consists of relatively few cells. Because L. ochracea has proven difficult to cultivate, its identification is based solely on habitat preference and morphology. We utilized cultivation-independent techniques to resolve this long-standing enigma. By selecting the actively growing edge of a Leptothrix-containing iron mat, a conventional SSU rRNA gene clone library was obtained that had 29 clones (42% of the total library) related to the Leptothrix/Sphaerotilus group (≤96% identical to cultured representatives). A pyrotagged library of the V4 hypervariable region constructed from the bulk mat showed that 7.2% of the total sequences also belonged to the Leptothrix/Sphaerotilus group. Sorting of individual L. ochracea sheaths, followed by whole genome amplification (WGA) and PCR identified a SSU rRNA sequence that clustered closely with the putative Leptothrix clones and pyrotags. Using these data, a fluorescence in-situ hybridization (FISH) probe, Lepto175, was designed that bound to ensheathed cells. Quantitative use of this probe demonstrated that up to 35% of microbial cells in an actively accreting iron mat were L. ochracea. The SSU rRNA gene of L. ochracea shares 96% homology with its closet cultivated relative, L. cholodnii, This establishes that L. ochracea is indeed related to this group of morphologically similar, filamentous, sheathed microorganisms

Recent Advances in Water and Wastewater Treatment with Emphasis in Membrane Treatment Operations

The present Special Issue brought together recent research findings from renowned scientists in this field and assembled contributions on advanced technologies that have been applied to the treatment of wastewater and drinking water, with an emphasis on novel membrane treatment technologies. The 12 research contributions highlight various processes and technologies that can achieve the effective treatment and purification of wastewater and drinking water, aiming (occasionally) for water reuse. The published papers can be classified into three major categories. (a) First, there are those that investigate the application of membrane treatment processes, either directly or in hybrid processes. The role of organic matter presence and fouling control is the main aim of the research in some of these studies. (b) Second, there are studies that investigate the application of adsorptive processes for the removal of contaminants from waters, such as arsenic, antimony, or chromate, with the aim of the efficient removal of the toxic contaminants from water or wastewater. (c) Lastly, there are studies that include novel aspects of oxidative treatment such as bubbleless ozonation

Removal of arsenic compounds from waste water by chemisorption filtration.” Theor

772 Arsenic occurs in natural water in the inorganic and organic forms. Inorganic arsenic arises from the dissolution of minerals of the arsenolite (As 2 O 3 ), arsenic oxide (As 2 ) 5 ), or realgar (As 2 S 2 ) type. As a rule, it is found and can present in the two oxidation states, arsenate (As(V)) and arsenite (As(III)). Either of them can dominate solution, depending on pH and the redox potential. Arsenates are thermodynamically stable inorganic species mainly occurring in surface water. Arsenites occur under reductive conditions in anaerobic ground waters. It has been established that the toxicity of arsenic depends on its oxidation state. In the biological systems, arsenites (trivalent form) are considerably more poisonous than arsenates, while the toxicity of organoarsenic compounds is generally lower than for the arsenic inorganic species Considerable study is being given to the development of promising technologies for arsenic removal, especially with the aim of achieving the newly approved maximum permissible arsenic concentration. The main purpose of the study is to develop the better practicable technology of arsenic removal from drinking and waste water. The standard processing includes coagulation with coagulants (iron chloride or aluminum sulfate) followed by the separation of the resulting insoluble deposit (by the deposition or direct filtration through a sand layer) In recent work It was the purpose of this work to assess the use of modified polymeric materials for removing arsenic from water and to determine the main parameters influencing the arsenic removal. These were the initial pH of the processed water, the initial arsenic concentration, the water contact time with the empty sorbent bed, the nature of arsenic associates, and the iron concentration in a solution used for the sorbent coating. The influence of the competitive anions such as phosphates, chlorides, nitrates, and carbonates in a water solution was also studied. The synthesized microporous polymer prepared by the intraphase emulsification of polyVVFE (or polyHIPE) was studied with the aim of revealing the effect of stirring time and water/monomer ratio on the structure of material. The novelty of this work consists in a systematic comparative study of the As(III) and As (V) removal and in the use of a fixed sorbent bed and a column loaded with polystyrene and polyVVFE granules coated with iron hydroxide. This is the first study on the use of polymeric materials as a filtration matrix in the sorptive filtration technology of arsenic removal from Abstract -The results of arsenic removal from water sources to a residual concentration of <10 µ g/l are presented. The main physicochemical parameters were established for the As removal by polystyrene, modified granules of a polyVVFE polymer, and iron hydroxide-coated calcium alginate granules. It is shown that adsorptive filtration is the effective method for arsenic removal

Efficiency and energy requirements for the transformation of organic micropollutants by ozone, O3/H2O2 and UV/H2O2

The energy consumptions of conventional ozonation and the AOPs O3/H2O2 and UV/H2O2 for transformation of organic micropollutants, namely atrazine (ATR), sulfamethoxazole (SMX) and N-nitrosodimethylamine (NDMA) were compared. Three lake waters and a wastewater were assessed. With p-chlorobenzoic acid (pCBA) as a hydroxyl radical (•OH) probe compound, we experimentally determined the rate constants of organic matter of the selected waters for their reaction with •OH (kOH,DOM), which varied from 2.0 × 104 to 3.5 × 104 L mgC-1 s-1. Based on these data we calculated •OH scavenging rates of the various water matrices, which were in the range 6.1-20 × 104 s-1. The varying scavenging rates influenced the required oxidant dose for the same degree of micropollutant transformation. In ozonation, for 90% pCBA transformation in the water with the lowest scavenging rate (lake Zürich water) the required O3 dose was roughly 2.3 mg/L, and in the water with the highest scavenging rate (Dübendorf wastewater) it was 13.2 mg/L, corresponding to an energy consumption of 0.035 and 0.2 kWh/m3, respectively. The use of O3/H2O2 increased the rate of micropollutant transformation and reduced bromate formation by 70%, but the H2O2 production increased the energy requirements by 20-25%. UV/H2O2 efficiently oxidized all examined micropollutants but energy requirements were substantially higher (For 90% pCBA conversion in lake Zürich water, 0.17-0.75 kWh/m3 were required, depending on the optical path length). Energy requirements between ozonation and UV/H2O2 were similar only in the case of NDMA, a compound that reacts slowly with ozone and •OH but is transformed efficiently by direct photolysis. © 2011 Elsevier Ltd

Removal of Arsenic, Chromium and Uranium from Water Sources by Novel Nanostructured Materials Including Graphene-Based Modified Adsorbents: A Mini Review of Recent Developments

Groundwater is commonly used as a drinking water resource all over the world. Therefore, groundwater contamination by toxic metals is an important issue of utmost concern for public health, and several technologies are applied for their effective removal, such as coagulation, ion exchange, adsorption, and membrane applications like reverse osmosis. Adsorption is acknowledged as a simple, effective and economic technology, which has received increased interest recently, despite certain limitations regarding operational applications. The respective scientific efforts have been specifically focused on the development and implementation of novel nano-structured adsorbent materials, which may offer extensive specific surface areas, much higher than the conventional adsorbents, and hence, are expected to present higher removal efficiencies of pollutants. In this paper, the recent developments of nanomaterial applications for arsenic, chromium and uranium removal from groundwaters are critically reviewed. Particularly, the use of novel composite materials, based mainly on hybrid metallic oxide nanoparticles and on composites based on graphene oxide (GO) (i.e., graphene-based hybrids), showed promising evidences to achieve efficient removal of toxic metals from water sources, even in full scale applications