Rotary drum composting of different organic waste mixtures.
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.
Kalamdhad
Ajay S
AS
Department of Civil Engineering, Indian Institute of Technology (TR), Roorkee, 247667, India. kalamdhad@gmail.com
Kazmi
Absar A
AA
D000818:Animals; D002244:Carbon / Q000737:chemistry; D002417:Cattle; D004755:Enterobacteriaceae; D029968:Escherichia coli Proteins; D005191:Family Characteristics; D005502:Food; D006863:Hydrogen-Ion Concentration; D008372:Manure; D009584:Nitrogen / Q000737:chemistry; D006109:Poaceae; D006180:Proton-Translocating ATPases; D012037:Refuse Disposal / Q000295:instrumentation* / Q000379:methods*; D012987:Soil; D012988:Soil Microbiology; D013696:Temperature; D013997:Time Factors; D014867:Water; D014934:Wood
D029968:Escherichia coli Proteins; D008372:Manure; D012987:Soil; D014867:Water; D002244:Carbon; D006180:Proton-Translocating ATPases; C101709:AtpH protein, E coli; D009584:Nitrogen