A study on the efficiency of the sequential batch reactor on the reduction of wastewater pollution from oil washing.

Industrial pollution discharges from washing fuel oils pose severe problems for the environment, particularly for the marine environment receiving these discharges. This work evaluates the biological treatment performance of wastewater (90 m3/h) rich in organic matter with low biodegradability using a sequential batch reactor (SBR) on a laboratory scale. The test using SBR was carried out for 25 days on a continuous cycle of 24 h (30 min of filling, 17 h of aeration, 4 h of anoxia, 2 h of settling, and 30 min of emptying). The feasibility of alternative sources of microorganisms from urban wastewater. The performance of the batch sequencing reactor was evaluated using turbidity, total suspended solids, chemical oxygen demand (COD), biological oxygen demand (BOD), ammonium, nitrate, and phenol as indicators. The results obtained showed that the COD/BOD ratio and the pollutant load vary from one campaign to another. The removal efficiency of COD, BOD, TSS (Total suspended solids), ammonium, nitrate, and phenol varies from 81%, 91%, 72%, 100%, 52%, and 63%. Thus, SBR-type treatment could be an interesting way to reduce pollution due to its simplicity, less space occupation, low energy consumption, and not requiring highly qualified personnel.

Pretreatment of industrial wastewater by natural flotation: application to pollution reduction from vegetable oil refinery wastewaters.

The objective of this study is to evaluate the effectiveness of the natural flotation process in reducing pollution with reasonable investment and operating costs of an industrial effluent of refining vegetable oils. Flotation tests were carried out in separating funnels and in drums of 30 l. The results obtained have shown that the volume of sludge produced during flotation is related to the pollutant load of the wastewater studied (process wastewater and acidic wastewater). The sludge volume is respectively 600, 12, and 120 ml/l for heavy, light, and medium loads respectively. Therefore, it is essential to find an effective way to remove oils and greases from polluted waters. Natural flotation eliminates on average 88% of COD for acid wastewater and 50% for process wastewater. However, the reduction of BOD5 showed 28 and 43% respectively for acid wastewater and process wastewater. In addition, the yield of fats and oils, TSS, and turbidity varies around 85%, 45%, and 88% respectively for acidic wastewater, while for process wastewater, elimination yields vary around 58%, 46%, and 46% respectively for the grease and oil parameters, the MES, and the turbidity. Flotation allows the elimination of 10659 Kg/day of greases and oils for process wastewater while it eliminates 5765 Kg/day for acidic wastewater. This reduces the cost of treatment related to chemicals and energy. Reducing pollution of wastewater by natural flotation could therefore help reduce the costs of treating wastewater, and recycling would then be more attractive for this purpose for the company.

Valorization of Opuntia ficus-Indica Pads and Steel Industry FeCl3-Rich Rejection for Removing Surfactant and Phenol from Oil Refinery Wastewater Through Coagulation-Flocculation.

BACKGROUND: Refinement of crude vegetable oil generates a large amount of wastewater and is a source of water pollution due to the presence of surfactants and phenols. Phenols are toxic aromatic compounds that can be lethal to fauna and flora, entraining the deceleration or blocking of the self-purification of biological treatments. In addition, surfactants can limit biological processes by inhibiting microorganisms that degrade organic matter. OBJECTIVES: The aim of the present study was to evaluate the treatment of refinery rejects loaded with phenols and detergents by coagulation flocculation using cactus pads (genus Opuntia) as a bio-flocculant and 30% iron(III) chloride (FeCl3) for surfactant and phenol removal. In addition, operating costs were evaluated for these pollution mitigation methods. METHODS: The effectiveness of cactus pads as a bio-flocculant and 30% FeCl3 for surfactant and phenol removal were studied using a jar test. The study was conducted on vegetable oil refinery wastewater from a refinery company in Casablanca, Morocco. RESULTS: The pollution load in wastewater varied widely from day to day. We evaluated the effect of cactus juice and 30% FeCl3 on high and low pollution loads. Opuntia pads showed a favorable potential for the treatment of low pollution load wastewater, with 78% and 90% of surfactant and phenol removed, respectively. However, the removal of high pollution load was less effective (42% and 41% removal of surfactant and phenol, respectively). The turbidity of low and high pollution load was reduced by 98.85% and 86%, respectively. The results demonstrate that 30% FeCl3 can effectively treat both low and high pollution loads (90% and 89% phenol removal, respectively, and 90% and 70% surfactant removal, respectively (optimal concentration 1.48 g/l). The turbidity was reduced by over 96% for both high and low pollutants. CONCLUSIONS: The results of the present study indicate that cactus as a natural flocculant and reject rich in FeCl3 could be effectively used for the low-cost effective treatment of crude vegetable oil refinery rejects. COMPETING INTERESTS: The authors declare no competing financial interests.

Petroleum sludge bioremediation and its toxicity removal by landfill in gunder semi-arid conditions.

In this investigation, petroleum sludge landfilling was carried out in order to assess the biodegradation degree and the final product quality. The microbial analysis showed a good microorganism proliferation which reinforces the biodegradation process. The total mesophilic and thermophilic microflora evaluated symmetrically as they increased at the intermediate stage and decreased at the final. The C/N and NH4+/NO3-ratios decreased while the polymerization degree increased at the end of the landfilling process. The total polyphenols and total petroleum C6 to C22hydrocarbons were removed by 71.6% and 73% respectively, and that affected the reduction of the phytotoxicity in a positive way. All these changes are in agreement with the efficiency of the biotransformation process and showed that petroleum sludge and filling reduced the toxic organic compounds and led to a stable final product.

Colour and COD removal of disperse dye solution by a novel coagulant: application of statistical design for the optimization and regression analysis.

The investigation presented here focussed on the steel industrial wastewater (SIWW) FeCl(3) rich as an original coagulant to remove the synthetic textile wastewater. Response surface methodology was used to study the cumulative effect of the various parameters namely, coagulant dosage, initial pH of dye solution, dye concentration and to optimize the process conditions for the decolourization and COD reduction of disperse blue 79 solution. For obtaining the mutual interaction between the variables and optimizing these variables, a 2(3) full factorial central composite rotatable design using response surface methodology was employed. The efficiencies of decolourization and COD reduction for disperse blue 79 solution were accomplished at optimum conditions as 99% and 94%, respectively.

Aerobic biodegradation of sludge from the effluent of a vegetable oil processing plant mixed with household waste: physical-chemical, microbiological, and spectroscopic analysis.

Sludge from a sewage treatment plant dealing with the effluent produced during the processing of crude vegetable oil (Lesieur-Cristal, Morocco) was composted in two mixtures (M1 and M2) with household waste obtained from landfill. The different physico-chemical characteristics of the final composts after 5 months of composting were, for M1 and M2, respectively: pH: 8.5 and 7.08; C/N: 10 and 16; proportion of decomposition: 78% and 55%, NH(4)(+)/NO(3)(-): 0.78 and 1.02. Monitoring the levels of lipid and total polyphenols showed a reduction of 81% and 72% for lipids and of 75% and 76% for polyphenols in M1 and M2, respectively. These reductions were paralleled by a rise in the humic acid content to reach 22 and 36mg/g, respectively. Overall, these results were confirmed by the FTIR spectroscopy study of the two mixtures. For M1, the FTIR spectra taken at different stages showed that during composting, biodegradation of the aliphatic compounds occurred as the proportion of aromatic structures increased. The transformations observed qualitatively were then confirmed quantitatively by the changes occurring in the various absorption ratios during composting. Mixture M2, however, presented strong absorbance of aliphatic compounds. These results were statistically confirmed by correlation tests and principal components analysis, which confirmed the maturity of the two composts, M1 having matured more than M2.

The fulvic acid fraction as it changes in the mature phase of vegetable oil-mill sludge and domestic waste composting.

Sludge resulting from the treatment of effluent from a vegetable oil mill, was composted mixed with domestic waste in a pile for five months. Different proportions of sludge and dry waste were mixed: M1 (1v/2v) and M2 (1v/1v). Monitoring different physical-chemical parameters showed the effect of the substrate on the microbiological activity and on the formation of fulvic acids, affecting the maturity of the final compost. Elemental analysis revealed that the fulvic acids of mixes M1 and M2 presented very low concentrations of carbon, hydrogen, and oxygen and a high level of nitrogen. The FTIR spectroscopy results showed a decrease during composting of the intensity of absorbance of the easily assimilable compounds that are predominant in the initial mixtures i.e. the carbohydrates (1170-1080 cm(-1)) in M1 and long aliphatic chains (2920 cm(-1)) in M2. For mix M1 there was enrichment in compounds bearing oxygen-containing moieties. In M2 it was the nitrogen-containing compounds (in the form of stable amides) which predominated at the end of composting. The first component of PCA analysis, PC1, accounted for 83% of the difference between two distinct groups of parameters governing degradation and restructuration of the fulvic acids during composting. PC2 (17%) explained the variance due to the level of free or less polycondensed compounds in the two mixtures. Oxidised polyphenolic and polysaccharide structures were the least free, or most polycondensed, in the fulvic structures of M1. In M2 fulvic acids however, it was the polyphenols and peptide structures that were involved in the bonding, most likely of the polyphenol-peptide type.