Olive mill wastewater as valuable source of animal feed and energy

An alternative process to treat olive mill wastewater has been proposed and its potential demonstrated in a pilot-scale plant. The treatment consists of an integrated physico-chemical system and a biological uni

Lactic acid production by electrodialysis .1. Experimental tests

none4Lactic acid, the production of which from cheap raw materials is attractive due to its great potential in the production of biodegradable polymers, can be obtained from fermentation broths using electrodialysis. This work discusses the feasibility of this process using commercial membranes, together with the influence of several operating parameters on the electrodialysis stack performance. It was found that it is possible to operate with high current efficiency values, while the overall recovery of sodium lactate depends on the current density. Electroosmotic water transport limits the maximum concentration value achievable using this technique.N. Boniardi;R. Rota;G. Nano;B. MazzaN., Boniardi; Rota, Renato; Nano, Giuseppe; B., Mazz

Dynamic Modeling of Waste-water Treatment Plants Based On Lemna-gibba

In this paper, a comprehensive process model able to simulate the behaviour of a waste-water treatment plant based on Lemna gibba has been developed. This model accounts for the main chemical and biochemical phenomena involved in a natural waste-water treatment system. Several comparisons with experimental data obtained both in mini-ponds and in real-size plants have confirmed the reliability of the model predictions

Fatigue behavior of duplex-treated samples coated with Cr(C,N) film

The effect of a Cr(C,N) PVD coating on the fatigue behavior of 42CrMo4 steel grade was investigated both in a quenched and tempered condition and after nitriding treatment. The latter, so-called “duplex process”, combines a nitriding pre-treatment in order to obtain a hard and stiff substrate and a PVD coating in order to reduce the friction coefficient and improve the wear resistance of tools and mechanical components. Prior to fatigue testing, the surface modifications were characterized by means of X-ray diffraction (XRD), residual stress distribution, Vickers nano-hardness measurements and scanning electron microscopy (SEM) analysis. For the quenched and tempered steels, the PVD coating acts as a high compressive residual stressed zone able to increase the fatigue resistance of the coated component. On the contrary, for the duplex-treated samples, a limited increase in the fatigue limit was detected with respect to uncoated nitrided samples. This result was interpreted by means of the residual stress gradient which does not show high differences for nitrided coated and uncoated samples