To compost, four piles were prepared. Organic wastes from four sources were collected. These wastes are fruit waste, vegetable waste, farm waste, and cooked leftover food waste. All this waste was put for composting in four windrow piles respectively. The quantity of organic waste in all four piles was kept the same 30kg in each. To maintain the C/N ratio of 30:1 dry leaves were added to each pile in equal quantity. The C/N ratio is one of the important parameters in the composting process and also for the quality of product compost (Azim et al., 2018). Saw dust was added to each pile as a bulking agent. The process of composting was monitored for 3 months to get the matured and stable compost from each pile. During this water was poured into composting piles to maintain the moisture. Moisture also plays an important role in composting because the microorganisms working in composting needs average of 50–60% moisture for their activity (Ameen et al., 2016).
Characteristics of raw material
Table 2
Physical characteristics of raw material
Type of waste | PH | Organic matter (%) | C/N ratio |
---|
a) Fruits waste | 7.2 | 79 | 38:1 |
b) Vegetable waste | 7.6 | 84 | 35:1 |
c) Farm waste | 6.6 | 90 | 27:1 |
d) Cooked leftover waste | 7.5 | 88 | 40:1 |
Table 3
Chemical characteristics of raw material
Type of waste | Total Nitrogen (g/kg) | Phosphorus (g/kg) | Potassium (g/kg) |
---|
a) Fruits waste | 18.5 | .04 | .92 |
b) Vegetable waste | 23.9 | 1.12 | 1.36 |
c) Farm waste | 26.8 | .36 | .42 |
d) Cooked leftover waste | 9.6 | .11 | .76 |
Several factors affect the process of composting (Hueso et al., 2012). The factors which are considered in our study are discussed here.
Temperature
The whole process of composting is about the biodegradation of organic matter by the microorganism. Temperature is a necessary factor for the metabolic activity of microorganisms. So it affect the biodegradation process of organic waste (Waszkielis et al., 2013). Further temperature is also a responsible factor in eliminating pathogens from the composting pile (Pandey et al., 2016). Due to the activity of microorganisms the temperature of the pile may exceed \({70}^{0}C\) and could deactivate the process of degradation. For this regular turning and observation of piles is necessary to maintain the temperature throughout the process (Sudharsan Varma & Kalamdhad, 2015). In our study, we maintain the temperature at about \(40\)-\({45}^{0}C\). To avoid excessive heat all the piles were turned over on regular basis.
The current experimental study was conducted at the campus of Bhartiya Skill Development University From January 2021 to April 2021. The lowest temperature (150C) and highest 330C were observed at the experimental site.
In the presented study the temperature range of each pile was maintained at 250-500 C.
In the case of ideal composting the range of \({P}^{H}\) is 5–8 (Zhang & Sun, 2016). If the \({P}^{H}\) exceed the range there would be reduction in microbial activity (Bernal et al., 2009). In current study \({P}^{H}\)was within the range of 6 -6.5 for all the compost piles. It supports the proper microbial activity.
C/N ratio
For proper working, the microorganism requires a 25–35 ratio of C/N which means 30 parts of carbon per part of nitrogen (F., 2015). To maintain the C/N ratio we added dry leaves and sawdust as a bulking agent in all four piles. Saw dust or other bulking agents can also accelerate the process of composting (X. Wang et al., 2015).
Moisture content
Moisture is also an important factor that affects the process of composting. The range of moisture for proper composting is 40–60% (Sudharsan Varma & Kalamdhad, 2015). In the presented study to maintain the moisture content water was poured regularly so that the moisture in each pile remains in range for the continued mechanism of composting. But if the moisture is more than the requirement then it restricts the oxygen flow in the pile and the condition might become anaerobic (Makan et al., 2013). So it is necessary to monitor the piles.
Aeration
The availability of oxygen in composting piles is a very important aspect of composting. Oxygen is a parameter that balances all other factors in piles (Latifah et al., 2015). The desirable oxygen concentration for composting is 15–20% and this concentration is directly linked to the microbial activity rate (Nakasaki & Hirai, 2017). For our study to provide proper aeration turning of compost piles on regular basis was done to make sure equal distribution of air in piles.
Use of Sawdust as a bulking agent
To improve the process of composting and the quality of compost bulking agents are effective (Rich et al., 2018), (Yang et al., 2013). In the current study, sawdust was used in each composting pile as a bulking agent.1kg of sawdust was used per 30kg of organic waste. It was observed that because of the presence of sawdust the process gets quick acceleration for composting. To observe the effect of sawdust on each type of waste two composting piles were prepared for each type of organic waste. One pile with sawdust and another without sawdust. As temperature and PH are the major factors that influence composting, these factors were monitored to identify the effect of sawdust in composting.