Nicholas Hytiris

The potential use of olive mill sludge in solidification process

The industrialisation of agriculture in the second half of the last century has been accompanied by an increase in production of organic wastes. Olive mill wastewater (OMW), a by-product of olive oil processing, is one such waste. It is produced in large quantities in the Mediterranean Region, an area that accounts for 95% of the total olive oil production worldwide. In recent years both physicochemical and biological treatment methods for OMW have been employed. Olive mill sludge (OMS), a by-product of the biological treatment methods, poses a major environmental threat, yet little research has been undertaken in its treatment and recycling. The aim of this study was to investigate the potential of using OMS as an additive for the development of construction materials. An attempt was made to solidify (fixate and stabilise) this sludge with cement, mixed with an improver/additive containing a mixture of natural and synthetic zeolites, alkaline elements, and oxides. The results to date appear to be very promising.

Electrochemical Growth Curves of Bio-Indicators for Sick Building Syndrome Diagnostics

Studies on electrochemical growth curve bio-indicators leading to the electrochemical growth curves approach for sick building syndrome (SBS) diagnostics are dis cussed. The ideas incorporated within electrochemical growth curve studies, i.e. the conductance, capacitance and impedance of plated out and slope nutrient gels, vary according to the micro-organism type and number of cells (spores) present. Thus, this observation may be applied to the design and study of real-time diagnostics for SBS. Using formaldehyde at selected concentrations within the OEL, COSHH regulation concentration levels, the conductivity, capacitance and impedance growth curves for Aspergillus parasiticus were examined using a Bactometer. Reproducibility ofthese curves and trigger levels of pollutant causing significant deviation from nor mal growth conductivity, capacitance and impedance curves is reported. The overall approach is evaluated as a possible technique for SBS diagnostics for other pollu tants including: ozone, carbon monoxide, carbon diox ide, sulphur dioxide and nitrogen dioxide.

ENHANCING SLOPE STABILITY WITH VEGETATION

Landslides can have serious impact on natural and human environment and their prevention and mitigation is of global concern. The ability of a slope to resist a landslide depends on the materials and the properties of which it is composed. This project focuses on the increased landslide resistance of a slope due to vegetation. The properties of the soil-root composite were measured in laboratory and, from these results, calculation and graphically based evaluation was used to determine their qualities for resisting landslide. The results show that vegetation roots had a stabilising effect on the slope, limited to the rooting depth. Knowing the rooting depth (generally between 0.5 and 1.5 m) and dependent on the species, a correlation between the ratio of root weight to soil weight and the slope ability to resist landslide was implied from experimental results and a hypothetical design chart and equation were derived.