Toxicity Identification and Reduction Evaluation in Petrochemical Effluents – SITEL Case

1992 ◽  
Vol 25 (3) ◽  
pp. 73-84 ◽  
Author(s):  
A. Brandelli ◽  
M. L. Baldasso ◽  
E. P. Goettems
Keyword(s):  
Aquatic Toxicity ◽  
Pimephales Promelas ◽  
Industrial Effluent ◽  
Liquid Waste ◽  
Toxicity Testing ◽  
Treatment System ◽  
Dissolved Air Flotation ◽  
Industrial Plants ◽  
Toxicity Reduction ◽  
Toxicity Identification

SITEL, Integrated Wastewater Treatment System of South Petrochemical Complex,has been processing liquid waste from this industrial area since November, 1982. The complex consists of an olefins plant and some second-generation plants that produce mainly thermoplastic resins. The raw industrial effluent is segregated in the plants in two main streams: organic and inorganic. The organic treatment consists of water-oil separator, equalization basin and dissolved air flotation (primary treatment), activated sludge and multi-media filters (secondary treatment) and stabilization ponds (tertiary treatment). The final effluent is applied on land by perforated PVC pipelines and sprinklers. In 1986, an aquatic toxicity test laboratory was implemented. It uses fish (Pimephales promelas) and crustaceans (Daphnia similis), according to methodology reported by EPA. A three-step protocol has been developed to characterize the whole effluent toxicity reduction in a, treatment system as well as to identify the sources of toxicity in industrial plants. The first step consists of toxicity identification and characterization of effluents at several monitoring points of SITEL. After analysing the results of the first step, it is possible to evaluate the toxicity reduction obtained by the treatment system and environmental toxicity evaluation. The second step consists of identification of the sources of toxicity in industrial plants through comparative study of organic and inorganic effluents of the complex, prioritizing the most toxic effluents. The last step consists of a toxic fraction identification, based on sequential physico/chemical fractionations of the effluent with associated toxicity testing using aquatic organisms. This paper presents the results that have been obtained so far and a previous evaluation of the main contributors for the toxicity of the effluents.

Municipal wastewater treatment by lime/ferrous sulfate and dissolved air flotation

1995 ◽  
Vol 31 (3-4) ◽  
pp. 285-294
Author(s):  
Luis Cáceres ◽  
René Contreras
Keyword(s):  
Chemical Treatment ◽  
Municipal Wastewater ◽  
Low Cost ◽  
Ferric Hydroxide ◽  
Liquid Waste ◽  
Treatment System ◽  
Iron Sulfate ◽  
Dissolved Air Flotation ◽  
Air Flotation ◽  
Dissolved Air

In this work a chemical treatment system for municipal wastewater using copper cementation effluent and lime as coagulants in combination with dissolved air flotation, was investigated. Copper cementation effluent (CCE) containing about 45% dissolved solids (density=1.31) is a liquid waste from a leaching process, which is disposed in large ponds by several copper mines in the North of Chile. CCE contains a combination of ferrous iron, sulfate, chlorine, magnesium, sodium, residual copper and other ions. For its use as a coagulant, CCE was treated using a low cost process. Ferric hydroxide flocs precipitated after CCE addition were efficiently removed by dissolved air flotation producing a low density froth. High suspended solid removal efficiency, process flexibility, short overall residence time in addition to low cost of chemicals used and precipitation of varied proportions of contaminants, including bacteria from wastewater, are the main features of this chemical treatment system.

Chemical characterization and biotreatability of effluents from an integrated alkaline-peroxide mechanical pulping/machine finish coated (APMP/MFC) paper mill

1997 ◽  
Vol 35 (2-3) ◽  
pp. 7-14 ◽  
Author(s):  
A. Schnell ◽  
M. J. Sabourin ◽  
S. Skog ◽  
M. Garvie
Keyword(s):  
Activated Sludge ◽  
Aquatic Toxicity ◽  
Wood Chip ◽  
Chemical Characterization ◽  
Toxicity Testing ◽  
Sampling Period ◽  
Paper Mill ◽  
Alkaline Peroxide ◽  
Conventional Activated Sludge ◽  
Treated Effluent

As part of an extensive audit of the Alkaline-Peroxide Mechanical Pulping (APMPTM) plant at the Malette Quebec Inc. mill in St. Raymond, Que., effluents were sampled from various stages of the process for comprehensive chemical characterizations, aquatic toxicity testing and anaerobic biotreatability assessments. In addition, untreated and secondary treated combined effluent from the integrated paper mill were sampled to determine the effectiveness of a conventional activated sludge process at the mill site. During the one-day sampling period, the APMP plant processed a mixed wood furnish consisting of 50% spruce/balsam fir and 50% aspen, with a chemical charge of 3.5% sodium hydroxide and 3.8% hydrogen peroxide on oven-dry fibre, while the Machine Finish Coated (MFC) paper production rate was 100 odt/d (oven dry metric tonnes per day). Measured production-specific contaminant discharge loadings from the novel APMP process were 56 kg BOD5/odt and 155 kg COD/odt in a combined effluent flow of 28 m3/odt. Sources of process effluent were chip washing, three stages of wood chip pretreatment and chemical impregnation (i.e., Impressafiner stages), interstate washing and pulp cleaning. The three Impressafiner pressates were found to be the most concentrated (i.e., 12-26 g COD/L) and toxic streams. Microtox testing of the pressates revealed EC50 concentrations of 0.07-0.34% v/v. The warm and concentrated effluents generated by the non-sulphur APMP process were found to be highly amenable to anaerobic degradation as determined by batch bioassay testing. Filterable BOD5 and COD(f) of the process effluents were reduced by 87-95% and 70-77%, respectively, with corresponding theoretical methane yields being attained. Acid-soluble dissolved lignin compounds exhibited biorecalcitrance, as revealed by limited removals of 34-55%, and were the main constituents contributing to residual COD(f), while resin and fatty acids (RFA) were reduced by 80-94%. The conservatively operated full scale activated sludge treatment process achieved a similar high 74% COD(f) removal from the whole mill effluent, while BOD5 and RFA reductions were virtually complete and the treated effluent was non-toxic, as measured by Microtox.

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