Environmental Technology

Freeman, M.B.; Bender, T.M.

doi: 10.1080/09593339309385269pmid: N/A

Abstract Polycarboxylates are added to home laundry detergents to aid in the production of the detergent and also in the cleaning process. Given the level of use of polycarboxylates for this application, it is important to consider their environmental fate and ecotoxicity. This paper presents new and detailed information on the fate of one of the common polycarboxylates, sodium polyacrylate, under realistic use conditions. Novel techniques employing radiolabelled materials will be described to follow the fate of the various components of the polymer's molecular weight distribution. From these and ecotoxicity data, we have been able to develop a safety assessment for this important detergent component.

Butcher, E.J.; Cheeseman, C.R.; Sollars, C.J.; Perry, R.

doi: 10.1080/09593339309385270pmid: N/A

Abstract Methods for leach testing solidified waste are reviewed and the inherent advantages of a flow‐through leach test are described. A modified triaxial cell has been developed for flow‐through leaching, and some initial results on testing a solidified waste, made by mixing a commercial metal hydroxide waste filter cake with cement and fly ash are presented. The results indicate the usefulness of this approach for studying simultaneous leaching of metals.

Norrström, Ann‐Catrine; Jacks, Gunnar

doi: 10.1080/09593339309385271pmid: N/A

Abstract Fourteen catchment areas of wells with acid groundwater were limed with rather high dosages of calcium carbonate, ranging from 1.6–5.0 kg m‐2. Three to four years after liming the drinking water of three wells gives a clear indication of the treatment. In two recharge areas the soil chemistry were intensively studied and the base saturation has increased to a depth of 60–70 cm from the surface. The ion balance has changed in the soil layers and a transport of base cations seems to be going on towards the groundwater.

El‐Gohary, Fatma A.; Abo‐El‐Ela, Sohair I.; El Kamah, Hala M.; Aly, H.I.

doi: 10.1080/09593339309385272pmid: N/A

Abstract Wastewater discharged from a light vehicle manufacturing company was the subject of this study. Reduction of Cr VI to Cr III from the electroplating wastewater was carried out, after which the electroplating wastewater was mixed with other industrial and human wastes prior to combined chemical‐coagulation‐sedimentation treatment. The results obtained showed that the use of lime as a coagulant produced a high quality effluent. To minimize the initial investment and operating costs, combined treatment of the wastewater under investigation and wastes discharged from a near by automobile manufacturing plant was carried out. In this case two treatment schemes were investigated. The results obtained showed that biological treatment via completely mixed activated sludge process removed most of the organic matters. Near complete removal of Cr III and Ni II was achieved. Ammonia was oxidized to nitrate. A final process design was developed. Economic evaluation of the methods adopted indicated that combined wastewater treatment from both companies, using chemical coagulation‐sedimentation is recommended.

Seif, Hamdy A.A.; Joshi, S.G.; Gupta, S.K.

doi: 10.1080/09593339309385273pmid: N/A

Abstract An anaerobic fixed film reactor was operated at temperatures between 49 and 55°C, as a thermophilic reactor using actual pharmaceutical wastewater, to observe the effects of temperature and cobalt addition on the performance of the reactor. The reactor was operated with a COD of 2500 mg L‐1 at HRT of 4,7 days. COD, TVA, SS, VSS, NH4‐N, PO4‐P and SO4 were measured. The temperature of 54°C was found to be the optimum operating temperature with respect to the removal efficiency. Cobalt addition did not affect COD removal and increased gas production but decreased methane percentage.

Mahmood, S. Naeem; Naeem, Sitwat; Basit, Najma; Usmani, Tanzil Haider

doi: 10.1080/09593339309385274pmid: N/A

Abstract Silver coated sand has been used for the disinfection of contaminated water. Highly contaminated water has been passed through 1:1, 1:2 and 1:3 mixtures of silver treated and untreated sands of 10, 35 and 60 mesh sizes and bactericidal efficiency of each mixture has been evaluated. Data in this study suggest that the sand mixtures of 35 mesh remove coliform and faecal coliform more effectively and may be used as a water disinfectant and the silver coated sand may also substitute silver impregnated activated carbon in water treatment equipment.

Susarla, Sridhar; Bhaskar, G.V.; Bhamidimarri, S.M. Rao

doi: 10.1080/09593339309385275pmid: N/A

Abstract The equilibrium and batch kinetic adsorption‐desorption characteristics of 2,4‐dichlorophenoxyacetic acid (2,4‐D), 2,4,5‐trichlorophenoxyacetic acid (2,4,5‐T), 2‐methyl‐4‐chloro‐phenoxyacetic acid (MCPA), 2,4‐dichlorophenol (2,4‐DCP), 2,4,5‐trichlorophenol (2,4,5‐TCP) and para ‐chloro‐ortho‐cresol (PCOC) in a volcanic soil were investigated. Freundlich type isotherms were used to describe the equilibrium data. The film transfer coefficients were determined from the batch adsorber initial uptake rate data. The kinetic experiments were satisfactorily analysed by a surface diffusion model and the results indicated that for each compound, the adsorption and desorption diffusion coefficients were of the same order.

Rego, V.S.; Pfeiffer, W.C.; Barcellos, C.C.; Rezende, C.E.; Malm, O.; Souza, C.M.M.

doi: 10.1080/09593339309385276pmid: N/A

Abstract Discharge of heavy metals from the Acari‐São João de Merití River System into Guanabara Bay and the physico‐chemical mechanisms involved in the transport of these pollutants to the sea are evaluated. Determination of Hg, Cd, Pb, Zn, Mn, Fe, Cr, Cu and Ni concentrations by atomic absorption spectrophotometry were carried out for water, suspended particulate matter and bottom sediment samples. Transport of heavy metals occurs primarily via the particulate phase where mobile forms of metals prevail. Contamination of bottom sediments are indicated for Hg, Cd, Pb, Zn, Cu and Cr.

Miana, Paola; Scotto, Silvia; Perin, Guido; Argese, Emanuele

doi: 10.1080/09593339309385277pmid: N/A

Abstract The purpose of this study was to evaluate the sensitivity to tributyltin (TBT) of two aquatic organisms belonging to two different levels of the feeding chain: Selenastrum capricornutum alga and Daphnia magna crustacean. The EC50 value at 96 h for Selenastrum capricornutum and the ones at 24 h and 45 h for Daphnia magna with relative confidence intervals and NOEC values were calculated. A partial stimulus effect was observed both for alga and crustacean at very low TBT concentrations. The data obtained were compared both with toxicity TBT values, obtained from bibliography, concerning invertebrates, fishes and algae and with the results obtained by a new in vitro test utilizing submitochondrial particles (SMP). The response of SMP to TBT confirmed that the inhibition of the respiratory functions is one of the mechanisms by which the TBT causes toxicity to intact cells as well as to more complex organisms.

Hamdi, M.; Ellouz, R.

doi: 10.1080/09593339309385278pmid: N/A

Abstract Anaerobic filter (AF) was compared with aerobic fluidized bed fermentor (AFBF) for treating detoxified Olive Mill Wastewaters by Aspergillus niger. The behaviour of AFBF is more difficult than AF. The AFBF removes 57% of total COD after elimination of TSS which correspond to sludge. The treatment of detoxified OMW by AF reduces the total COD and soluble COD at 67 and 68.1% respectively. As regard to double role of AF, physical retention and anaerobic mineralization, the reduction of TSS was 62.9%. AFBF is less economic than AF because of consumption of aeration energy and of the very high production of secondary sludge. Moreover, AF produces biogas at 80% of methane. The black colour of OMW is weakly reduced only by AF.