Gulen Iskender

Assessment of Occupational Health and Safety for a Gas Meter Manufacturing Plant

This study investigates the occupational health and safety for a gas meter manufacturing plant. The risk assessment and management study is applied to plastic injection and mounting departments of the factory through quantitative Fine Kinney method and the effect of adopting 5S workplace organization procedure on risk assessment is examined. The risk assessment reveals that there are 17 risks involved; 14 grouped in high risk class (immediate improvement as required action); 2 in significant (measures to be taken as required action) and one in possible risk class (monitoring as required action). Among 14 high risks, 4 can be reduced by 83 % to be grouped under possible class when 5S is applied. One significant risk is observed to be lowered by 78 % and considered as possible risk due to the application of 5S. As a result of either 67 or 50 % reductions in 7 high risks, these risks are converted to be members of significant risk group after 5S implications.

Reducing the Toxicity and Recalcitrance of a Textile Xenobiotic Through Ozonation

Lignosulphonates are known as biologically-difficult-to-degrade, multi-purpose macromolecules that potentially may create toxicity problems in biological activated sludge treatment systems and/or in receiving water bodies. In the present experimental work a commercial lignosulfonate formulation (COD = 320 mg/g; BOD5 = 8 mg/g) frequently being used as an auxiliarly chemical in the cotton and polyester dyeing process was subjected to ozonation (≈ 3 g O3/CODo) at different pH (6 and 12) and ozone doses (1,400 and 5,300 mg/h) to improve its biodegradability and reduce its toxicity. Experimental findings have indicated that ozonation of lignosulphonates is a rather kinetically limited process. 20 min ozonation of lignosulfonate at a dose of 1,400 mg/h and an initial pH of 12 resulted in an 8-fold decrease in acute toxicity (EC50 = 3−4% v/v) towards the micralgae Phaedactylum tricornutum) and 50% reduction in its inert COD content (CODo = 600 mg/L). COD-based molecular size distribution indicated that the lignosulphonate formulation was cleaved to low-molecular-weight COD fractions after ozonation under the above mentioned conditions.

Pretreatment of Ceftriaxone Formulation Effluents: Drawbacks and Benefits

As a result of its high inert COD content (approximately 250 mg/l accounting for 63% of the total COD) and the possibility to evoke antibiotic resistance, Ceftriaxone sodium antibiotic formulation effluent (molecular formula = C18H16N8Na2O7S3) requires an additional treatment process preferably as chemical pretreatment along with the biological one to meet the discharge standards. The present study dealt with the effect of applying ozonation and the H2O2/O3 process (perozonation) as a partial pretreatment stage to the mentioned antibiotic formulation effluent. 20 min of ozonation at a rate of 1500 mg/(l·h) removed 48% COD, whereas a COD removal efficiency of 53% could be achieved via perozonation in the presence of 31 mM H2O2. Ozonation completely eliminated the inhibitory effect of the effluent towards activated sludge, however at the same time it also resulted in an increase in acute toxicity towards the marine microalgae Phaeodactylum tricornutum. On the other hand, by perozonation a considerable reduction in the inhibitory effect of the studied effluent towards heterotrophic biomass was achieved, unfortunately perozonation also increased the toxicity of the effluent towards the marine microalgae.