SUMMARY
Physicochemical and biological parameters were used in this
study for compost quality assessment. Fifty households were selected
for collecting the waste from the houses in different quarters of Erbil
city for seven days. The average generation rate of solid waste in
Erbil city was 0.632 kg.capita????1.day????1, 732.18 tons/day for all inhabitants
of Erbil city. Degradable portion of refuse is estimated by 0.377
kg.capita????1.day????1 which represent 60% of the solid waste composition.
Four different procedures were applied to degradation of organic waste
for production of compost: Aerobic, anaerobic, pit and vermicomposting.
Aerobic compost was produced in aerobic condition, temperature
reach 55oC during composting, and it needs 21 days for maturation,
while anaerobic compost was prepared in the anaerobic condition, it
required about two months for maturing and releasing of ammonia.
Vermicomposting characterized by using special types of worms called
red worms (Eisenia foetida), which plays an important roles in degradation
of organic matter during composting.
Pit composting reach to maturation phase underground for the longer
time (about six months). When all compost types mature three replicated
of compost samples were taken from each type of composts for
analyzing. Some physicochemical parameters were analyzed including;
pH, EC, Nitrates, Sodium, Organic carbon content, Organic matter content,
Cation exchange capacity, Ash content, C/N ratio, Total nitrogen,
Total phosphorus, Potassium, Color, Moisture, Porosity, Bulk density
and Water holding capacity. The pH value of composts was found to
lie on the alkaline side; it ranged from (7.73 to 8.50). The electrical conductivity
ranged from (244.83 to 1404.66 ms/cm) at studied composts.
The nitrate concentration varied from (7.94 to 22.20 mg NO3-N. l????1).
Sodium level ranged from (0.012 to 0.054 %), the minimum value was
recorded at anaerobic compost. Organic carbon content and organic
matter content ranged from (15.67 to 24.03 %) and (26.95 to 41.33 %)
respectively. The cation exchange capacity varied from (9.20 to 51.19

cmolc/kg), the maximum value was observed in pit compost. Ash
content ranged from (45.55 to 55.69 %). C/N ratio was important parameters
of composts maturity was related to amount of carbon and nitrogen
in compost, ranged from (7.48 to 39.93), the minimum value observed
in anaerobic compost. Total nitrogen was ranged from (0.617 to
2.188%), the minimum value observed in pit compost. On other hand,
total phosphorus ranged from (0.610 to 2.123%), the maximum value
observed in worm compost. Potassium of the studied compost ranged
from (0.001 to 0.004%). The color of all composts was gray to dark
brown in the color because contained a large amount of organic matter
particulary the humin compound. Total moisture content was ranged
from (26.33 to 39.38 %), the minimum value observed from worm compost.
The porosity ranged from (34.31 to 66.76 %) at studied composts.
Bulk density varied from (0.79 to 1.57 g/cm3). While water holding
capacity was ranged from (35.12 to 46.17 %), the minimum value observed
in pit compost. However, biological properties measured from
prepared composts which include; Total heterotrophic count, Total coliform,
Fecal coliform, Salmonella, Total fungi and actinomycetes count.
Total heterotrophic count ranged from (114- 150*105 CFU.g????1). Total
coliform and fecal coliform ranged from (30-170*105 CFU.g????1) and (30-
45*105 CFU.g????1) respectively. The maximum value of total coliform
and fecal coliform observed in anaerobic and aerobic compost respectively.
Salmonella bacteria in studied composts ranged from (11-30*103
CFU.g????1), the maximum value observed in aerobic compost. Total
fungi count ranged from (30-370*103 CFU.g????1), the minimum value
was observed in pit compost because of not favorable temperature during
composting. Total actinomycetes ranged from (53-295*103 CFU.g????1)
for prepared composts, the maximum value was observed in anaerobic
compost.
Elements concentration analyzed during composting, therefore, divided
into two groups: essential elements and non-essential elements. Also
essential elements including; Boron, Calcium, Cobalt, Copper, Iron,
Magnesium, Molybdenum, Selenium, Nickel and Zinc. Calcium is im-

portant elements for plants ranged from (51.4 to 128 mg/kg), the maximum
value observed in pit compost. Cobalt and copper concentration
ranged from (0.006 to 0.043 mg/kg) and (0.042 to 0.246 mg/kg) respectively.
Non-essential elements including; Aluminum, Arsenic, Mercury,
Cadmium, Chromium and Lead. Arsenic is very toxic elements ranged
from (0.005 to 0.011 mg/kg). Mercury concentration ranged from (0.01
to 0.036 mg/kg). In which all compost types contain little amount of
arsenic and mercury because the component of composts contains only
organic compounds, not any toxic materials.
Germination index also analyzed of the composts to determined germination
rate and phytotoxicity of studied composts, using three seed
type of plants for germination such as tomato, wheat and chickpeas. GI
ranged from (0.55 to 3.01%), the minimum value observed in chickpeas
seed in pit compost. According to (California compost quality council,
2002) based on the effect of three extract solution on plant seeds classified
anaerobic compost as very mature, while pit compost as immature,
where as, aerobic and worm compost as mature
The different indices were used to assess the quality of compost included
compost quality index, fertilizing index and clean index. The
value of compost quality index was ranged from (1.03 to 25.28). The
studied compost fall in different quality, the worm and anaerobic compost
in extremely good quality but pit and aerobic as poor quality. Fertilizing
index value ranged from (3.3 to 4.06 %), while the clean index
value for studied composts was 5%. Based on FI and CI classification,
aerobic and anaerobic composts falls under the best quality category,
but pit and worm composts fall within the very good quality category.
In general the prepared compost are suitable for different agriculture
purpose.

12-12-2016