Liming Treatment Effect on Vermicomposting Process of Different Combination of Restaurant Wastes and Cow Dung

With rising urbanization and change in lifestyle and food habits، the amount of waste material has been increasing rapidly and its composition changing. Vermicomposting is the best method of converting waste material into a useable soil amendment with the use of earthworms and microorganisms. The study began with collecting restaurant waste (as organic waste) from restaurants. The selected wastes were mixed with cow-dung (as bulk material) in various bed combination ratios: 1:0 (100% cow dung)، 2:1 (34% restaurant waste + 66% cow dung)، and 1:1 (50% restaurant waste + 50% cow dung). For study of liming effect on vermicomposting process، two types of treatments were prepared by adding 1% (w/w) and without limestone in bed combinations. Vermicomposting step started by inoculation 10 fold earthworms Eisenia foetida with 4. 46 ± 0. 17 g total biomass، approximately. The investigation was conducted in a factorial complete randomized design with six treatments and three repetitions. In during of study، the sampling carried out 3 time per 1 month from each bioreactor and some chemical properties such as pH، electrical conductivity (EC)، organic carbon (OC)، total nitrogen (TN)، exchangeable potassium (Kex) and available phosphorus (Pav) were measured. At the end of study total and immature biomasses of earthworms were determined. The results shown that with increasing in the proportion of waste restaurant and adding 1% lime have led to a rise in nutrients content (TN، Kex and Pav) of vermicompost، significantly. Respectively، vermicomposting has also led to 12%، 53%، 51%، and 19% increasing in EC، TN، P، and K and 5%، 19، and 46% decreasing in pH، OC، and C/N as compared to beginning of the process. Also، bed combination، liming treatment factors، and interaction of them have led to a growth in total and immature biomasses of earthworms. 2:1 vermibed with 1% lime has highest growth and reproductive rate (156% total biomass) between other treatments after 3 month.