Composting of Sewage Sludge with a Simple Aeration Method and its Utilization as a Soil Fertilizer

Abstract

The objective of this study was to examine the feasibility of sewage sludge composting using a simple aeration method. Two consecutive composting trials (run A and run B) using Japanese sludge and woodchips (1:1, v/v) were conducted in cubic boxes (0.45 × 0.45 × 0.45 m) made by plywood at Okayama University. Air was forced up through small holes perforated on two open-ended parallel PVC pipes (ø 16 mm, 0.25 m apart) laid at the base. The results show that compost temperatures were rapidly increased to the peak points of 47.4 °C (run A) and 74.8 °C (run B) within the first 2-3 days and varied depending on each composting run and vertical locations. The changes in physicochemical properties with particular attention to inorganic nitrogen (NH-N, NO-N) and free amino acid nitrogen (FAA-N) indicated that the biodegradation took place by different mineralization pathways during the composting process. The degradation of organic matter into amino acids followed by ammonification was predominant in run B, whereas the nitrification was greater in run A. A pot experiment using the two finished composts and their raw materials was carried out to study their effectiveness as fertilizer to Komatsuna (Brassica rapa var. perviridis). The total plant biomass produced by the composts was similar to chemical fertilizer. The lowering proportions of FAA-N/T-N, NH-N/NO-N, and C/N ratios in the composts compared to those in raw materials was found to correlate with the increase in plant biomass.

Effects of Sewage Sludge Application on Plant Growth and Soil Characteristics at a Pinus sylvestris var. mongolica Plantation in Horqin Sandy Land

“…Consequently, the woodland utilization of SS resulted in an improvement of the soil properties, such as modifying soil pH, bulk density, and organic matter, and dramatically increasing NO 3 − -N. Specifically, the soil pH and NO 3 − -N were positively correlated with the aboveground biomasses in the understory (r = 0.649, p < 0.05; r = 0.600, p < 0.05, respectively). The amendment of sandy soil fertility also promoted tree height and herbaceous coverage, even though there were no significant relationships with those indicators of soil nutrition (Table 4), which is consistent with previous reports [65,99]. Ferreiro-Domínguez et al [51] also observed the effects of SS application (conversion into TN amount of 50 or 100 kg ha −1 ) on soil chemical properties that resulted in positive impacts on the understory production and tree growth in a P. radiata D. Don plantation.…”

Diversity of arthropods on Acacia mangium (Fabaceae) and production of this plant with dehydrated sewage sludge in degraded area

“…Crops cultivated using stabilized sewage sludge include the Japanese mustard spinach, Brassica rapa L. var. perviridis (Brassicales: Brassicaceae) in Japan [3]. Sewage sludge can be re-used as fertilizer in forest plantations, degraded area under recovery process and in agriculture, reducing production costs and environmental risks [4][5][6].…”

Potential and Mechanisms for Stable C Storage in the Post-Mining Soils under Long-Term Study in Mitigation of Climate Change

“…Such observations indicate the supported influence of the application of additional organic matter such as sewage sludge for storing carbon in the soil. Other studies show that sewage sludge [3] or compost application on post-mining soils influences the increase of TC in the soil [29]. The study of Singh et al [30] on coal mine soil also indicated an increase in carbon stock with the duration of the reclamation process.…”