太湖沉水植物残体理化性质和资源性分析

Characterization and valorization potential of submerged macrophyte residues from Taihu Lake

太湖区域的沉水植物残体产生量大、二次污染严重,亟需解决其资源化利用问题。资源化利用技术的选择取决于生物质废物的理化性质。为此,本研究分析了太湖区域5种沉水植物和1种对照浮水植物的生物化学组成、元素组成、厌氧和好氧生物稳定性以及热转化过程特征。结果表明:沉水植物的木质纤维素含量(以干质量计)为17.1%~31.7%,低于常见的挺水植物和浮水植物;蛋白质、脂肪含量(以干质量计)分别为11.3%~19.9%和1.8%~3.2%,低于大部分浮水植物;沉水植物具有木质纤维素含量低、适口性好的特点,可经过加工后用作饲料。生物化学甲烷潜力的分析结果显示,粗破碎沉水植物的累计甲烷产量(以有机质质量计)为106.2~150.2 mL·g^(-1),低于常规厌氧消化处理物料的产气量,不适合以单一底物方式进行厌氧消化。沉水植物的7日好氧呼吸量(O2,以干质量计)在534.5~698.8 mg·g^(-1)范围内,一级降解速率常数为0.051~0.097 d-1,快速降解的特性显示其适合采用堆肥技术进行处理。热重分析表明沉水植物的热转化温度低,更适合生产用作吸附剂、土壤调理剂的生物炭。

To treat a large amount of harvested submerged macrophyte residues from the Taihu Lake area and address serious secondary pollution issues,there is an urgent need to solve problem of resource utilization.To that end,the biochemical composition,elemental composition,anaerobic and aerobic biostability,and thermal conversion process characteristics of five different submerged macrophytes from Taihu Lake area were studied and compared with one floating macrophyte.The results showed that the lignocellulose content of the submerged macrophytes was 17.1%–31.7%(dry weight),which was generally lower than that of emergent and floating macrophytes.The protein and lipids contents of the submerged macrophytes were 11.3%–19.9%and 1.8%–3.2%,respectively,which were lower than those of most floating macrophytes.With low lignocellulose contents,submerged macrophytes have good palatability;thus,they can to be further processed as feed.The results of the biochemical methane potential analysis showed that the cumulated methane production of roughly broken submerged macrophytes was 106.2–150.2 mL·g^(-1),which was lower than the methane production of conventional feedstocks of anaerobic digestion,which were not suitable as a single substrate for anaerobic digestion.The respiration activity of the submerged macrophytes for seven days ranged from 534.5–698.8 mg·g^(-1),and the first-order degradation rate constant was 0.051–0.097 d-1.The rapid degradation characteristics of the submerged macrophytes showed their potential for composting treatment.The thermogravimetric analysis showed that submerged macrophytes were suitable for the production of biochar,which is used as an adsorbent and soil conditioner,owing to their low thermal conversion temperatures.