Frišták Vladimír, Polt'áková Lucia, Soja Gerhard, Kaňková Hana, Ondreičková Katarína, Kupcová Elena, Pipíška Martin
Department of Chemistry, University of Trnava, Trnava, Slovakia.
Institute for Chemical and Energy Engineering, Universität für Bodenkultur Wien, Vienna, Austria.
PeerJ. 2024 Sep 25;12:e18184. doi: 10.7717/peerj.18184. eCollection 2024.
The main objective of the present work was to assess the ecotoxicological safety of the use of thermochemically treated sewage sludge from the wastewater treatment plant (WWTP) of a distillery plant as a soil additive in agricultural soils based on its physicochemical characteristics and the bioaccumulation of selected elements in the plant tissues of maize (). We have carried out physicochemical characterization (pH, EC, C, C, CEC, N, H, ash content, PAHs) of sewage sludge feedstock (SS) and sludge-derived biochar (BC) produced by slow pyrolysis at a temperature of 400 °C. The effect of 1% (w/w) amendment of SS and BC on soil physicochemical properties (pH, EC, C), germination of ryegrass, soil rhizobacteria and microorganisms, as well as on the accumulation and translocation of selected elements in maize () was studied. The results show that pyrolysis treatment of distillery WWTP sludge at 400 °C increases pH (from 7.3 to 7.7), C(from 28.86% to 36.83%), N (from 6.19% to 7.53%), ash content (from 23.59% to 50.99%) and decreases EC (from 2.35 mS/cm to 1.06 mS/cm), CEC (from 118.66 cmol/kg to 55.66 cmol/kg), H (from 6.76% to 1.98%) and Σ18 PAHs content (from 4.03 mg/kg to 3.38 mg/kg). RFA analysis of SS and BC showed that pyrolysis treatment multiplies chromium (Cr) (2.2 times), nickel (Ni) (2.96 times), lead (Pb) (2.13 times), zinc (Zn) (2.79 times), iron (Fe) (1.26 times) in the obtained BC, but based on an ecotoxicological test with earthworms , we conclude that pyrolysis treatment reduced the amount of available forms of heavy metals in BC compared to SS. We demonstrated by a pot experiment with a maize that a 1% addition of BC increased soil pH, decreased EC and C and had no significant effect on heavy metal accumulation in plant tissues. According to the results of the three-level germination test, it also does not affect the germination of cress seeds (). There was a significant effect of 1% BC addition on soil microbial community, and we observed a decrease in total microbial biomass and an increase in fungal species variability in the soil. Based on these results, we conclude that BC represents a promising material that can serve as a soil additive and source of nutritionally important elements after optimization of the pyrolysis process.
本研究的主要目的是基于其理化特性以及玉米植株组织中选定元素的生物累积情况，评估将酿酒厂污水处理厂（WWTP）经热化学处理的污泥用作农业土壤添加剂的生态毒理学安全性。我们对污泥原料（SS）和在400℃下通过慢速热解产生的污泥衍生生物炭（BC）进行了理化特性分析（pH、电导率、碳、碳、阳离子交换量、氮、氢、灰分含量、多环芳烃）。研究了1%（w/w）的SS和BC添加量对土壤理化性质（pH、电导率、碳）、黑麦草发芽、土壤根际细菌和微生物的影响，以及对玉米中选定元素的积累和转运的影响。结果表明，在400℃下对酿酒厂污水处理厂污泥进行热解处理会使pH升高（从7.3升至7.7）、碳含量升高（从28.86%升至36.83%）、氮含量升高（从6.19%升至7.53%）、灰分含量升高（从23.59%升至50.99%），并降低电导率（从2.35 mS/cm降至1.06 mS/cm）、阳离子交换量（从118.66 cmol/kg降至55.66 cmol/kg）、氢含量（从6.76%降至1.98%）和18种多环芳烃总量（从4.03 mg/kg降至3.38 mg/kg）。对SS和BC的RFA分析表明，热解处理使所得BC中的铬（Cr）增加了2.2倍、镍（Ni）增加了2.96倍、铅（Pb）增加了2.13倍、锌（Zn）增加了2.79倍、铁（Fe）增加了1.26倍，但基于对蚯蚓的生态毒理学试验，我们得出结论，与SS相比，热解处理降低了BC中重金属有效形态的含量。我们通过玉米盆栽试验证明，添加1%的BC会提高土壤pH、降低电导率和碳含量，且对植物组织中的重金属积累没有显著影响。根据三级发芽试验结果，它也不影响水芹种子的发芽。添加1%的BC对土壤微生物群落有显著影响，我们观察到土壤中总微生物生物量减少，真菌物种变异性增加。基于这些结果，我们得出结论，在优化热解工艺后，BC是一种有前景的材料，可作为土壤添加剂和营养重要元素的来源。
