A critical review on inhibition of anaerobic digestion process by excess ammonia.

http://sourcedb.igsnrr.cas.cn/zw/lw/201209/P020120927317502474088.pdf

Effect of aeration rate, C/N ratio and moisture content on the stability and maturity of compost.

Use of biochar as bulking agent for the composting of poultry manure: Effect on organic matter degradation and humification

Poultry litter (PL) is a potentially underused fertilizer because it contains appreciable amounts of N, P, K, and micronutrients. However, treatments like composting to reduce potential pathogens, weed seeds, and odor often result in high losses of N through NH3 volatilization. Biochar (BC) has been shown to act as an absorber of NH3 and water-soluble NH4+ and might therefore reduce losses of N during composting of manure. We produced three PL compost mixtures that consisted of PL without added BC (BCO), PL + 5% BC (BC5), and PL + 20% BC (BC20). The BC was produced from pine chips and used without further modifications. Three replicates of each treatment were placed in nine bioreactors to undergo composting for 42 d. The entire composting experiment was repeated three times in a complete-block design. Moisture content, temperature, pH, mass loss, gas (NH3, CO2, H2S) emissions, C, and nutrient contents were measured periodically throughout the experiments. Results showed no difference in PL mass loss with BC addition. Moisture content decreased, pH increased significantly, and peak CO2 and temperatures were significantly higher with BC20 compared with BC0. These results indicate a faster decomposition of PL if amended with BC. Ammonia concentrations in the emissions were lower by up to 64% if PL was mixed with BC (BC20), and total N losses were reduced by up to 52%. Biochar might be an ideal bulking agent for composting N-rich materials.

Reducing Nitrogen Loss during Poultry Litter Composting Using Biochar

Composting technology in waste stabilization: On the methods, challenges and future prospects.

Nitrogen loss in chicken litter compost as affected by carbon to nitrogen ratio and turning frequency.

A b s t r a c t. Composting of chicken manure mixed with sawdust (chicken litter) was performed using the turned windrow method. The aim was to investigate the effects of turning frequency on some physicochemical properties of chicken litter. The three turning frequency treatments were: no turning, turning every 3 days and every 7 days. The initial physicochemical properties of chicken litter were determined. The moisture content of the treatments was adjusted to 55% (w.b.) at the beginning of composting and no moisture adjustment was done thereafter. The results showed that turning frequency did not affect (P > 0.05) pH, temperature, rate of composting and maturation time, but it affected (P < 0.05) moisture content, dry matter, total carbon, total nitrogen and carbon to nitrogen ratio of composting piles. Losses were observed in moisture content (61.82-75.8% of the initial moisture content), dry matter (7.68-13.01% of the initial dry matter), total carbon (51.71-62.24% of the initial total carbon) and total nitrogen (45.36-79.61% of the initial total nitrogen). The losses of total carbon were attributed to organic matter degradation, while those of total nitrogen were largely attributed to ammonia (NH 3 ) volatilization. Moisture loss and C:N ratio increased as turning frequency increased. All the treatments reached maturation at about 70 days, when the pile temperatures dropped to near ambient temperature. C:N ratio increase and losses in total carbon and total nitrogen were significantly higher in the turned windrows (treatments TF7 and TF3) than in the unturned windrow (treatment TF0). In conclusion, the short maturation time was attributed to low moisture levels in the piles.

Effects of turning frequency on composting of chicken litter in turned windrow piles

Evaluation and kinetics of biogas yield from morning glory (Ipomoea aquatica) co-digested with water hyacinth (Eichhornia crassipes)

Passive aeration composting of chicken litter: Effects of aeration pipe orientation and perforation size on losses of compost elements

Raw chicken manure was co-composted with sawdust in turned-windrow piles to understand the effects of carbon to nitrogen (C:N) ratio and turning frequency (TF) on composting. Carbon to nitrogen ratios of 20:1, 25:1 and 30:1, and turning frequencies of every 2 days and every 6 days were experimented. Properties of the chicken litter (chicken manure + sawdust) periodically monitored during the composting process were moisture content (MC), temperature, pH, total nitrogen (TN), total carbon (TC) and C:N ratio while dry matter (DM), total phosphorus (P) and total potassium (K) were examined at the end of composting. During composting, MC of the piles was periodically replenished to 55%. The results showed that C:N ratio had significant (p ≤ 0.05) effect on pile temperature, TN, TC, C:N ratio, DM, P and K while TF had significant (p ≤ 0.05) effect on pile temperature, pH, TC, C:N ratio and K. A significant part of the TN losses were attributed to NH3 volatilization while that of the TC losses were attributed to OM degradation. It was observed that moisture loss increased as C:N ratio and TF increased. All treatments reached stability at about 87 days as indicated by the decline of pile temperatures to values close to ambient temperature.

Gbolabo A. Ogunwande

Papers

Nitrogen loss in chicken litter compost as affected by carbon to nitrogen ratio and turning frequency.

Effects of turning frequency on composting of chicken litter in turned windrow piles

Evaluation and kinetics of biogas yield from morning glory (Ipomoea aquatica) co-digested with water hyacinth (Eichhornia crassipes)

Passive aeration composting of chicken litter: Effects of aeration pipe orientation and perforation size on losses of compost elements

Effects of Carbon to Nitrogen Ratio and Turning Frequency on Composting of Chicken Litter in Turned-Windrow Piles