This investigation was conducted at Sakha Agricultural Research Station, Kafr El-Sheikh Governorate and divided into two sections. The aim of the first section (during summer season 2003) is to study some chemical and biological characteristics of sewage sludge and treating of sewage sludge with drying beds, hydrate lime and composting with plant residues (rice straw, corn stalks and cotton stalks).The second section amis to study the effect of their application on some soil chemical properties and wheat yield under pot experiments during 2003-2004 winter growing season. The important findings could be summarized as follows:- Improving sewage sludge by using drying beds, chemically by addition of 5% lime and biologically by composting with plant residue caused reduction in the soluble heavy metals contents and killing all pathogens     (Fecal, strepto coliform) and Salmonella & Shigella . Application of different composting materials to the soil increased the EC values. The highest EC value (6.8 dSm^-1) was observed in case of 4% lime compost followed by 4% cotton compost(3.5 dSm^-1) .The highest pH value was also obtained in case of lime compost followed by cotton compost, corn compost, rice compost and sewage sludge compost, but all pH values  were lesser than the control (8.81).The application of composting materials also increased the values of macro, micro-nutrients(N, P, K, Mn, Zn & Cu) and heavy metals (Pb, Cd & Ni) in soil after cultivation compared with control. The highest increase in trace elements was obtained with the soil treated by sewage sludge followed by the soil treated by plant residues. In wheat grains, the macro and micro elements content were influenced by different composted materials. The increase in NPK content in wheat grains could be arranged as following sequence: sewage sludge treatment > lime compost > plant residues compost. Similar results were obtained with wheat straw. Physiological parameters (total carbohydrate and protein in grains, and total chlorophyll in leaves) of wheat plant with all treatments were increased according to the following sequence: soil treated with sewage sludge > soil treated with lime compost > different compost materials (rice straw, corn stalks and cotton stalks). Values of plant height, , number of grains / spike, 100 grain  weight, straw and grain yields were significantly increased in response to sewage sludge treatments compared with control. The highest growth parameters and yield components of wheat plants were obtained with 4% sewage sludge compost. Results show that, the uptake of the  Egyptian adult per day of trace elements in wheat grains was in accordance with the critical levels of WHO (1996). Therefore, it could be concluded that concentration of all elements are within the normal range and not exceed the WHO limits.