Composting of animal manures and chemical criteria for compost maturity assessment. A review

Maturity and stability parameters of composts prepared with a wide range of organic wastes

Carbon mineralization from organic wastes at different composting stages during their incubation with soil.

Transformation of organic matter during co-composting of pig manure with sawdust.

One of the most versatile and remunerative techniques for handling biodegradable solid wastes is composting. A large variety of such wastes of plant, animal, and synthetic origins can be gainfully composted, at scales varying from a household bin to a large industry. Compost also has an inexhaustible market as a soil conditioner and fertilizer. Apart from being a source of nitrogen, phosphorus, potassium, and other nutrients for plants, compost is also believed to suppress soil-borne diseases in plants. These virtues make composting an ideal option for processing the enormous quantities of biodegradable solid wastes that are generated in the world. In this article, a review of the state of the art of compost science is presented, encompassing the history, the mechanism, the production, the characteristics, and the effects of composting. It is hoped that this effort would stimulate further interest in composting and in the appreciation of its benefits.

Solid Waste Management by Composting: State of the Art

https://digital.csic.es/bitstream/10261/5162/1/BW-review-1989.pdf

Evaluation of city refuse compost maturity: a review

http://digital.csic.es/bitstream/10261/5165/1/AEE-1992.pdf

Determination of maturity indices for city refuse composts

A piling test with urban refuse (R-pile) and urban refuse +sewage sludge (R+S-pile) was carried out to study the evolution of organic matter during composting, and compost maturity. The R+S-pile maintains during around 20 days the limit of thermal inactivation of the micro-organisms. Therefore, the exclusive determination of temperature in piling composting plants cannot be considered in all cases as the conclusive criterion to estimate the grade of biological stability of compost. The biooxidative phase was 75 days and the optimization of C/N ratio in the water-soluble phase (C/N w ) and cation-exchange capacity (CEC) occurs in the maturation phase. Likewise, the C/N ratio in the solid phase (C/N s ) cannot be considered as a valid parameter to evaluate the maturity degree of compost: the R-pile reached the optimal value of 15 in full thermophilic phase, with an optimal value of the initial material of 28. The period in which practical temperature stabilization is achieved with a C/N w ratio lower than 6 and a CEC value higher than 60 meq 100 g −1 , on an ash-free material basis, may constitute the most valid criterion for establishing the optimum degree of maturity.

/pdf/composting-of-domestic-refuse-and-sewage-sludge-i-evolution-4a2xr9uw7q.pdf

Composting of domestic refuse and sewage sludge. I. Evolution of temperature, pH, C/N ratio and cation-exchange capacity

http://digital.csic.es/bitstream/10261/5164/1/BT-1992.pdf

Relationships between organic carbon and total organic matter in municipal solid wastes and city refuse composts

Iglesias Jim6nez, E. and P6rez Garcia, V., 1992. Composting of domestic refuse and sewage sludge. II. Evolution of carbon and some "humification" indexes. Resour. Conserv. RecycL, 6: 243-257. The evolution, during composting of city refuse (R-pile) and city refuse + sewage sludge co-composting (R + S-pile), of total organic matter (TOM) and some forms of carbon: total organic carbon (Ct), oxidizable carbon (Co), alkaline-extractable carbon (Cox), humic acid-like carbon (Cha), and fulvic acid-like carbon (Cfa), was evaluated. The results were correlated with some maturity parameters, namely, C/N ratio in the solid phase (C/Ns), C/N ratio in the water-soluble phase (C/Nw), and cation-exchange capacity (CEC), to examine the relationships between the mineralization of the organic matter, biological stability of compost, and "humification". The regression analysis was carried out considering jointly all the data points of both the R-pile and the R + S-pile, to extrapolate new maturity criteria irrespective of the initial composition of the urban raw material used for composting. The results show that the CEC/Ct and ChJCfa ratios may also be considered to be good maturity parameters. A value higher than 1.9 for both ratios, in addition to a value lower than 6 for the C/Nw ratio, may be considered as a suitable indicator of a high degree of maturity in composts of urban origin (municipal solid waste and sewage sludge composts).

/pdf/composting-of-domestic-refuse-and-sewage-sludge-ii-evolution-cqczklbwzm.pdf

Victor Perez Garcia

Papers

Evaluation of city refuse compost maturity: a review

Determination of maturity indices for city refuse composts

Composting of domestic refuse and sewage sludge. I. Evolution of temperature, pH, C/N ratio and cation-exchange capacity

Relationships between organic carbon and total organic matter in municipal solid wastes and city refuse composts

Composting of domestic refuse and sewage sludge. II. Evolution of carbon and some "humification" indexes