Environmental Technology

Kijjanapanich, Pimluck; Annachhatre, Ajit P.; Esposito, Giovanni; Lens, Piet N.L.

doi: 10.1080/09593330.2014.889219pmid: 24956793

Construction and demolition debris (CDD) is a product of construction, renovation or demolition activities. It has a high gypsum content (52.4% of total gypsum), concentrated in the CDD sand (CDDS) fraction. To comply with the posed limit of the maximum amount of sulphate present in building sand, excess sulphate needs to be removed. In order to enable reuse of CDDS, a novel treatment process is developed based on washing of the CDDS to remove most of the gypsum, and subsequent sulphate removal from the sulphate-rich CDDS leachate. This study aims to assess chemical techniques, i.e. precipitation and adsorption, for sulphate removal from the CDDS leachate. Good sulphate removal efficiencies (up to 99.9%) from the CDDS leachate can be achieved by precipitation with barium chloride (BaCl 2) and lead(II) nitrate (Pb(NO 3)2). Precipitation with calcium chloride (CaCl 2), calcium carbonate (CaCO 3) and calcium oxide (CaO) gave less efficient sulphate removal. Adsorption of sulphate to aluminium oxide (Al 2O 3) yielded a 50% sulphate removal efficiency, whereas iron oxide-coated sand as adsorbent gave only poor (10%) sulphate removal efficiencies.

Achour, Raouf; Abriak, Nor-Edine; Zentar, Rachid; Rivard, Patrice; Gregoire, Pascal

doi: 10.1080/09593330.2014.889758pmid: 24956794

The main objective of this study is to show the ability of fine dredged material (mainly silty material) to be used in road construction project. This paper is divided into three parts. In the first part, the physical, the mineralogical and the mechanical characteristics of the used fine dredged sediments, as well as their chemical composition and environmental impacts are presented. In the second part, the methodology developed to design the road made from dredged fine sediment is developed. The third part of the paper focuses on the presentation of the road construction and the interpretation of analyses made on cores drilled samples from the road and measurements of the deflection of the road. The environmental assessment, based on leaching tests, is also performed at different issues.

Deng, Qiaosi; Dhar, Bipro Ranjan; Elbeshbishy, Elsayed; Lee, Hyung-Sool

doi: 10.1080/09593330.2014.889759pmid: 24956795

This study revealed that ammonium exchange of natural zeolite could be an economical method of nitrogen removal from the permeates of anaerobic membrane bioreactors (AnMBRs). It was found that the mass ratio of Na + to significantly affected regeneration efficiency (RE), not simply NaCl concentration. Batch experiments showed that the mass ratio of 750 g Na +/g was required to achieve RE over 90% in 2 h at pH 9. However, the alkaline regeneration at pH 12 significantly decreased the mass ratio down to 4.2 in batch tests. It was confirmed that the alkaline regeneration only needed NaCl 10 g/L (the mass of Na + to of 4.2) for RE of 85% in 2 h of reaction time in continuous column tests. Economic analysis showed that this alkaline regeneration decreased chemical costs over 10 times as compared with a conventional regeneration method. A significant bottleneck of zeolite processes would be the requirement of substituting exhausted zeolite with virgin one, due to the reductions of ammonium exchange capacity and RE.

Kumar, Ramesh; Pal, Parimal

doi: 10.1080/09593330.2014.889760pmid: 24956796

Nanofiltration (NF) of ammoniacal wastewater containing phenol and cyanide has been investigated for effective separation of these hazardous pollutants and for the subsequent downstream chemical treatment resulting in valuable by-product generation. Four different types of composite polyamide commercial NF membranes (Sepro, USA) were tested under different operating conditions including transmembrane pressure and recovery rate (RR). At a transmembrane pressure of 15 bar, the achieved rejection of cyanide and phenol were 95% and 93%, respectively (concentrated stream) when the permeate contained 85% of ammonium-N. A high flux of 120 L m−2 h−1 was achieved during NF at a concentrated mode, with a volumetric cross-flow rate of 800 L h−1 at a pH of 10.0. The RR was 60% for the NF1 membrane. Fenton's reagents (7.0 and 3.75 g L−1 H2O2 and FeSO4·7H2O, respectively) were used to degrade more than 99% of pollutants present in the concentrated stream. In the permeate side, 97% of was precipitated out as struvite by using Mg2+:NH4:PO4+ in 1:1:1 molar ratio at pH 9.0.

Liu, Yuankun; Hu, Jun; Wang, Jianlong

doi: 10.1080/09593330.2014.889761pmid: 24956797

The radiation-induced removal of sulphadiazine (SD) belonging to the heterocyclic sulphonamides pharmaceuticals was investigated by gamma irradiation at different conditions in laboratory scale. The influence of initial SD concentrations, pH values, O2 and N2 on SD degradation was determined. The experimental results showed that gamma-ray irradiation was efficient for removing SD from wastewater. SD could be completely removed at an absorbed dose of 10 kGy. The degradation kinetics of SD conformed to the first-order kinetic equation. When SD concentration was in the range of 10–30 mg/L, the dose constant (d) decreased with an increasing initial SD concentration. The mineralization of SD, in terms of total organic carbon removal, was not obvious at a low absorbed dose, but it increased to more than 75% at 100 kGy. The biodegradability of SD was improved after irradiation, suggesting that irradiation could be used as a pretreatment technology for treating SD-containing wastewater. The possible degradation pathway of SD was tentatively proposed based on the analysis of intermediate products during gamma irradiation.

Damasceno, F.R.C.; Freire, D.M.G.; Cammarota, M.C.

doi: 10.1080/09593330.2014.890249pmid: 24956798

The use of rhamnolipid-type biosurfactant produced by Pseudomonas aeruginosa was evaluated for solubilization of fat present in effluent from a poultry processing plant, followed by anaerobic biological treatment. The rhamnolipid was used in combination with enzyme pools produced by solid medium fermentation of the fungi Penicillium simplicissimum and Penicillium brevicompactum. In experiments with raw effluent, the accumulation of fat caused the specific methane production (SMP) to be much less than with pretreated effluent (0.074 vs. 0.167 L CH 4/g chemical oxygen demand (COD) removed). In experiments with pretreated effluent, the SMP ranged from 0.105 to 0.207 L CH 4/g COD removed. A statistical analysis of the results of four sequential batches found that all variables had a significant effect on the SMP in the fourth batch. A fifth batch was initiated for three conditions, and it led to the highest SMP when compared with the control, which showed similar behaviour for the SMP over time, ending up with values three times greater than the SMP in the control conditions. The residual oil and grease analysis revealed removals from 51% to 90% with pretreated effluent and only 1% in the control conditions with raw effluent. Thus, the best synergistic effect of fat release/hydrolysis of effluent components from a poultry processing plant was found with a 0.5% P. brevicompactum pool and rhamnolipid at half the critical micelle concentration (24 mg/L).

Pontes, P.P.; Chernicharo, C.A.L.; Sperling, M. Von

doi: 10.1080/09593330.2014.891052pmid: 24956799

This study aimed at assessing the influence of the return of excess aerobic sludge from a trickling filter (TF) upon the anaerobic digestion process in an upflow anaerobic sludge blanket (UASB) reactor, by evaluating its effect on the kinetics of the decay of specific organic matter (carbohydrates, proteins and lipids), as well as on the concentrations of volatile fatty acids in the UASB reactor. A pilot-scale UASB/TF system was used to perform the experiments, operating with (phase 2) and without (phase 1) excess sludge return from the TF to the UASB reactor. Sampling was carried out at different heights of the UASB reactor (0, 25, 125 and 225-cm height), and profile concentrations were determined for the following parameters: carbohydrates, proteins, lipids and volatile fatty acids. First-order kinetics showed the best fit to the decay of concentrations of carbohydrates, proteins, lipids and chemical oxygen demand (COD) in the UASB reactor. The parameters showing the best fit to the first-order kinetics were proteins and COD, during the sludge return phase. The occurrence of higher apparent reaction constants was further observed during the sludge return phase. For an influent COD concentration of 600 mg L −1 and hydraulic retention times of 2.1, 2.6 and 3.0 h in phase 1, the effluent COD concentrations were 125.3, 88.4 and 62.4 mg L −1, respectively, whereas in phase 2, the effluent COD concentrations were 75.5, 47.6 and 30.1 mg L −1, respectively.

Idowu, I.A.; Alkhaddar, R.M.; Atherton, W.

doi: 10.1080/09593330.2014.891658pmid: 24956800

Mecoprop-p herbicide is often found in wells and water abstractions in many areas around Europe, the UK inclusive. There is a growing environmental and public health concern about mecoprop-p herbicide pollution in ground and surface water in England. Reviews suggest that extensive work has been carried out on the contribution of mecoprop-p herbicides from agricultural use whilst more work needs to be carried out on the contribution of mecoprop-p herbicide from non-agricultural use. The study covers two landfill sites in Weaver/Gowy Catchment. Mecoprop-p herbicide concentrations in the leachate quality range between 0.06 and 290 μg l−1 in cells. High concentration of mecoprop-p herbicide in the leachate quality suggests that there is a possible source term in the waste stream. This paper addresses the gap by exploring possible source terms of mecoprop-p herbicide contamination on landfill sites and evaluates the impact of public purchase, use and disposal alongside climate change on seasonal variations in mecoprop-p concentrations. Mecoprop-p herbicide was found to exceed the EU drinking water quality standards at the unsaturated zone/aquifer with observed average concentrations ranging between 0.005 and 7.96 μg l−1. A route map for mecoprop-p herbicide source term contamination is essential for mitigation and pollution management with emphasis on both consumer and producer responsibility towards use of mecoprop-p product. In addition, improvement in data collection on mecoprop-p concentrations and detailed seasonal herbicide sales for non-agricultural purposes are needed to inform the analysis and decision process.

López Fernández, Raquel; Coleman, Heather M.; Le-Clech, Pierre

doi: 10.1080/09593330.2014.892539pmid: 24956801

This study focuses on the performance of a submerged membrane photocatalytic reactor for the removal of 17β-oestradiol (E2) in the presence of humic acid (HA). In addition to the impact of operating parameters, such as membrane pore size, ultraviolet (UV) intensity and hydraulic retention time (HRT), the influence of long-term operation was also assessed by advanced characterization of the fouling layer formed on the membrane. The tighter (0.04 μm) hollow fibre polyvinylydene fluoride (PVDF) membrane was found to exhibit not only higher HA removal than the (0.2 μm) module (85% and 75%, respectively), but also greater transmembrane pressure (TMP) values and higher irreversible fouling. Long-term operation conditions have been simulated by conducting an ageing catalyst process and demonstrated a decrease in performance obtained with time. The artificially aged TiO2 resulted in higher TMP values and lower HA removals (about 10–20% decrease) compared with the non-aged catalyst. For E2 removal in the presence of HA, the passive adsorption of the oestrogen onto the organic matter was found to be significant (40% of the E2 adsorbed after 1 h), demonstrating the importance of the nature of the water matrix for this type of treatment process. An increase in the UV light intensity was observed to favour the E2 elimination, leading to more than 90% removal when using 64 W combined with PVDF membrane and an HRT of 3 h.

Kamika, Ilunga; Momba, Maggy N.B.

doi: 10.1080/09593330.2014.893023pmid: 24956802

This study assesses and compares vanadium toxicity in its different oxidation states towards bacterial isolates (Pseudomonas putida and Bacillus licheniformis) and protozoan isolates (Peranema sp. and Trachelophyllum sp.). The isolates were exposed to various concentrations of V in mixed liquors and their tolerance to V was assessed at 30°C at a pH of 4. The results revealed that the increase in V oxidation state increased its toxicity to bacterial isolates, whereas its toxicity decreased for protozoan isolates. Among the bacterial isolates, P. putida was found to be more tolerant to V3+(24 h-median lethal concentration (LC50): 390 mg/l), V4+(24 h-LC50: 230–250 mg/l) and V5+(24 h-LC50: 180–200 mg/l), whereas for the protozoan isolates, Peranema sp. appeared to be more tolerant to V3+(24 h-LC50: 110–120 mg/l), V4+(24 h-LC50: 160–170 mg/l) and V5+(24 h-LC50: 160–200 mg/l). A comparison of both groups of organisms revealed Trachelophyllum sp. as the most sensitive organism to V at its various oxidation states. The visual and spectrophotometric methods used to assess V reduction revealed that P. putida was the only isolate able to reduce V5+, V4+ and V3+ to V2+ in mixed liquor media. Vanadium (+2) in concentrations of approximately 46.46 mg/l, 29.57 m mg/l and 38.01 mg/l found in the media was treated with V3+, V4+ and V5+, respectively, and inoculated with P. putida. This study revealed that the ability of V reduction, adopted with P. putida, can be an effective strategy to remove V from polluted environments. This study also showed that the toxicity of V, in terms of its oxidation states, differs from one species to another and in kingdoms.