On Killing vector fields on a tangent bundle with g-natural metric Part I

The tangent bundle of a Riemannian manifold (M, g) with a non-degenerate g− natural metric G that admits a Killing vector field is investigated. Using Taylor’s formula (TM,G) is decomposed into four classes. The equivalence of the existence of Killing vector field on M and TM is proved. More detailed investigaton of the classes is done in the part II of the paper

Fenton and Fenton-like AOPs for alum sludge conditioning : effectiveness comparison with different Fe2+ and Fe3+ salts

Currently, organic polymers are adopted in alum sludge (aluminium-coagulated drinking water treatment sludge) conditioning. However, there are important concerns regarding the use of these polymers because of the unknown and long-term effects of the potential release of excess polymer to the surrounding environment when the sludge is landfilled. Therefore, as an initiative action, this study aimed at investigating alternative chemical conditioning methods and focused mainly on exploiting Fenton (Fe2+/H2O2) and Fenton-like (Fe3+/H2O2) reagents as the conditioner. Experiments have been conducted to test the effectiveness of Fenton’s reagent (containing the ferrous salts of chloride, sulphate or oxalate), Fenton-like reagent (containing ferric salts of chloride and sulphate) and the coagulation method using FeCl3 for an alum sludge conditioning at a constant hydrogen peroxide and iron salt concentrations of 125 and 20 mg/g DS (dry solids), respectively. The effectiveness on dewaterability of the alum sludge demonstrated that the maximum reduction (%) of SRF (specific resistance to filtration) and CST (capillary suction time) of 74 % and 47 %, respectively, can be obtained when Fenton’s reagent was adopted for sludge conditioning. Such reduction of 64% for SRF and 38% for CST can be achieved when Fenton-like reagents were applied.Not applicable12M embargo@ release after 25/11/2011 - AV 25/8/201