Rotary drum composting of different organic waste mixtures

Abstract

The effects of three different mixtures of organic waste on composting in a rotary drum were examined by measuring changes in physico-chemical and biological parameters. It was observed that the time courses of the three mixtures: run A (grass cuttings, vegetable waste and food waste), run B (cattle manure, vegetable waste and sawdust) and run C (cattle manure, food waste, vegetable waste, paper waste and sawdust) were quite diverse. Run B, with initial C/N ratio 22 and containing a large proportion of cattle manure produced high quality and mature compost within 20 days. It showed a final total nitrogen (2.1%), final total phosphorus 3.52 g kg(-1), final total organic carbon (TOC) (24.8%) and final moisture content (44%). At the end of 20 days, higher degradation led to final chemical oxygen demand (COD) (454 mg L(- 1)), biochemical oxygen demand (BOD) (107 mg L(- 1)), fecal coliform (1.2 x 10(2) bacteria g(- 1)), fecal streptococci (85 bacteria g(-1)) and low electrical conductivity (1.658 dS m(-1)), respectively. Furthermore, run C with initial C/N ratio of 30 and containing a larger amount of food and vegetable waste produced good quality compost and resulted in 4.34% total nitrogen and 2.42% total phosphorus after 20 days, but, it had higher final fecal coliform 2.5 x 10(4) bacteria g( -1), fecal streptococci 2.1 x 10(4) bacteria g(-1), high TOC and NH(4)-N and a BOD/COD ratio of 0.63, which rendered it hygienically unsafe and immature. Finally, run A with initial C/N ratio of 15 showed a higher amount of EC (4.84 dS m(-1)), NH(4)-N, BOD/COD ratio of 0.4 with 15% nitrogen loss, which indicated an unstable product even after 20 days of composting. Therefore, it was found that rotary drum composting of a combination of cattle manure, vegetable waste and sawdust resulted in a primary stabilized compost within 20 days of composting.

Inside the small-scale composting of kitchen and garden wastes: Thermal performance and stratification effect in vertical compost bins

“…In previous work, as well as in other authors experiences, elevated EC values were observed in compost made from dining wastes. This is associated to the presence of cellulosic material in the feedstock, such as napkins and tablecloths made with paper (Arrigoni et al, 2015;Faverial and Sierra, 2014;Kalamdhad and Kazmi, 2009a;Kalamdhad and Kazmi, 2009b). However, in this study, the differences in the EC values between the upper and the lower layers of the composter, also would show leachates accumulation in the lower part of the composter; leachates frequently include dissolved salts and, thus, increase compost electrical conductivity.…”

“…Decentralized composting has been successfully implemented for kitchen and garden organic wastes treatment in institutions, neighborhoods and homes, at low costs (Platt et al, 2014;Smith and Jasim, 2009). Thus, this system represents an attractive technology alternative for the municipal organic waste fraction treatment in various socio-economic and technological contexts (Kalamdhad and Kazmi, 2009a;Kalamdhad and Kazmi, 2009b). Furthermore, small-scale composting is also an innovative way to involve generators as a key factor in their own waste treatment, raising community environmental awareness (Adhikari et al, 2010;Faverial and Sierra, 2014).…”

Feasibility and Performance Evaluation of Different Low-Tech Composter Prototypes

“…According to literature, compost produced from catering waste, kitchen waste, or produced using home composters, has a wide variation on electrical conductivity (EC) values (from 1 to 10 dS. m -1 ) [2,34,35], but high soluble salt concentrations are more usually found in compost produced from cooked or preserved food [36]. Although, similar composed feedstock was equally incorporated into each composter, compost from AAC showed half EC values of those obtained from EVC and ATC; this could be attributed to a lower salt loss through lixiviation in these last two treatments prototypes.…”

In-vessel co-composting of yard waste and food waste: an approach for sustainable waste management in Cameron Highlands, Malaysia

“…YW used in this study had low initial moisture content of 35.63 ± 0.4% while FW recorded moisture content of 58.24 ± 0.4%. Optimum initial moisture content of raw feedstock ranges between 50 and 60% (Kalamdhad and Kazmi 2009). The analyses showed that YW and FW contained 17.17 ± 0.5% and 31.77 ± 0.5% of carbon, and 0.28 ± 0.2% and 3.43 ± 0.2% of nitrogen.…”

“…The temperature inside the composter changed mainly due to heat generation as a result of degradation of organic matters by microorganisms and because of ambient air blown inside the composter for aeration purposes (Arslan Topal et al 2016). Greatest thermophilic activity would be observed during composting process when the temperature ranges between 52 and 60°C (Kalamdhad and Kazmi 2009;Mohee and Mudhoo 2005).…”