Effects of adding biochar on the preservation of nitrogen and passivation of heavy metal during hyperthermophilic composting of sewage sludge

Figures & data

Table 1. The basic physicochemical characteristics of raw materials.

Materials	TOC/g·kg^−1	TN/g·kg^−1	pH	EC/mS·cm^−1	Moisture content/%	C/N ratio
sewage sludge	410.1	30.6	7.02	2.75	82.8	13.4
corn straw	347.3	8.23	7.11	3.87	8.2	42.2

TOC: total organic carbon. TN: total nitrogen. EC: electrical conductivity

Figure 1. Changes of (a) temperature, (b) moisture level and (c) pH in each pile during the composting process.

Figure 2. Changes of germination index and C/N ratio in each pile during the composting process.

Figure 3. Changes of TN, NH₄⁺-N, and NO₃^–N in each pile during the composting process.

Figure 4. Ammonia emission in each pile during the composting process.

Figure 5. Changes in the (a) Zn concentration, (a’) Zn fraction, (b) Cu concentration, (b’) Cu fraction, (c) Pb concentration, and (c’) Pb fraction during the composting process.

Table

WWTPs	Wastewater Treatment Plants
SS	Sewage Sludge
OM	Organic Matter
TC	Thermophilic Composting
HTC	Hyperthermophilic Composting
HSs	Humic Substances
CS	Corn Straw
UT	Ureibacillus Terrenus
SC pile	Sewage sludge + Corn straw
SCA pile	Sewage sludge + Corn straw + 5‰ UT Agent
SCAB pile	Sewage sludge + Corn straw + 5‰ UT Agent +5% Biochar; GI: germination index
ICP-MS	Inductively Coupled Plasma Mass Spectrometry
Bcr	Community Bureau Of Reference
EPSs	Extracellular Polymeric Substances

Data availability statement

Due to the nature of this research, participants of this study did not agree for their data to be shared publicly, so supporting data is not available.