الفهرس 
1. INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The increasing energy demand and the large amount of wastes produced daily
and especially organic wastes were the main factors led to conduct this work study.
In this study, anaerobic digestion was chosen as a suitable strategy for
converting kitchen waste to energy suitable to be used at home. The experiments were
carried out in three stages as follow:
First stage: Kitchen waste composition
By collecting three different kitchen waste samples from three living standards (high level, medium level and low level), the characteristics of kitchen waste were
known as TS, VS, moisture content, ash content and organic content. High level,
medium level and low level have TS% of 24.35, 32.53 and 32.41%, respectively,
VS% of 86.65, 89.91 and 89.55%, respectively, moisture content% of 75.65, 67.47 and 67.59%, respectively, ash content% of 13.35, 10.09 and 10.45%, respectively and organic content% of 45.04, 68.98 and 68.00%, respectively.
There were significant differences among the three living standards H.L., M.L.
and L.L. in their TS%, moisture content% and organic content% and there were not
significant differences in their VS% and ash content%.
Three laboratory scale reactors were utilized to study the effect of living
standards on biogas yield in the AD process. 9 liters kitchen waste samples (with dilution ratio 1:1) were fed in a batch type method at room temperature for 30 days retention time. High level, medium level and low level had cumulative gas quantity of
16.560, 17.592 and 16.446 L, respectively and with production gas rate of 13.95, 14.82 and 13.85 L/kg VS, respectively.
Second stage: Design and construction of biogas digester for kitchen waste
A 72-liter home biogas digester was designed and equipped with an automatic
control system in order to control some of AD parameters and then enhance biogas
yield. A pretreatment containing mixing unit, heating unit and a mixing unit were added to the unit and also the automatic control system including fire detector for safety insurance, temperature and gas sensors, mobile application for monitoring and
some other components to make the unit more controllable and easy and safe to use.92
Third stage: Evaluate the performance of the digester
In order to evaluate digester performance after adding the automatic control
system, the digester was run for three intervals (phases) (each with 30 days RT). The first without using control system at ambient temperature (phase І) and two phases with using the control system in two temperature levels, mesophilic range at 35ºC
(phase ІІ) and thermophilic range at 50ºC (phase ІІІ). Digester was fed in a
continuous feeding method with 4 liters/day (2 liters waste + 2 liters water).
Temperature, pH and produced gas quantity was monitored daily (except holidays of Friday and Saturday of every week) (5 days a week).
Cumulative gas quantity for phase І, phase ІІ and phase ІІІ were 165.92,
498.92 and 616.56 L, respectively which means that, by using control system and
raising temperature to 35 and 50ºC, gas quantity multiplied by 3 and 3.71,
respectively.