China’s carbon neutrality: an extensive and profound systemic reform

● China has pledged ambitious carbon peak and neutrality goals for mitigating global climate change. ● Major challenges to achieve carbon neutrality in China are summarized. ● The new opportunities along the pathway of China’s carbon neutrality are discussed from four aspects. ● Five policy suggestions for China are provided. China is the largest developing economy and carbon dioxide emitter in the world, the carbon neutrality goal of which will have a profound influence on the mitigation pathway of global climate change. The transition towards a carbon-neutral society is integrated into the construction of ecological civilization in China, and brings profound implications for China’s socioeconomic development. Here, we not only summarize the major challenges in achieving carbon neutrality in China, but also identify the four potential new opportunities: namely, the acceleration of technology innovations, narrowing regional disparity by reshaping the value of resources, transforming the industrial structure, and co-benefits of pollution and carbon mitigation. Finally, we provide five policy suggestions and highlight the importance of balancing economic growth and carbon mitigation, and the joint efforts among the government, the enterprises, and the residents.     

Effects of exogenous acylated homoserine lactones on biofilms in biofilters for gaseous toluene treatment

● Biofilm formation was enhanced by exogenous AHLs. ● EPS production and microbial adhesive strength of biofilm were promoted. ● Exogenous AHLs improved the performance of biofilters treating toluene. Biofilters are typical biofilm reactors, and they usually have poor biofilm formation resulting in limited reactor performance. Exogenous acylated homoserine lactones (AHLs) can enhance biofilm formation in many bioreactors based on quorum sensing regulation. However, their effect on biofilm in biofilters utilized for volatile organic compound (VOC) removal is unknown and needs to be investigated. In this study, the effects of the exogenous AHLs on biofilters for gaseous toluene removal were investigated. Analysis of biofilms in biofilters showed that the addition of exogenous AHLs considerably enhanced biofilm growth; the average biofilm concentration increased by 18%. Furthermore, the average biofilm coverage proportions in biofilters with and without exogenous AHLs were 17 % and 13 %, respectively, demonstrating the positive effect of exogenous AHLs on biofilm coverage. In particular, exogenous AHLs promoted the production of extracellular polymeric substances and the microbial adhesive strength of the biofilm. In addition, the exogenous AHLs showed no significant effect on the gaseous toluene removal efficiency of the biofilter. These results show that exogenous AHLs can enhance biofilm formation and can guide the application of exogenous AHLs in VOC biofilters.     

Highly efficient and selective removal of phosphate from wastewater of sea cucumber aquaculture for microalgae culture using a new adsorption-membrane separation-coordinated strategy

● A new adsorption-membrane separation strategy is used for phosphate removal. ● PVC/Zr-BT shows a selective adsorption ability to low-concentration phosphate. ● Low concentration of P below 0.05 mg/L was achieved in actual wastewater treatment. ● Algal biomass production served as a demonstration of phosphorus recycling. Enhanced phosphorus treatment and recovery has been continuously pursued due to the stringent wastewater discharge regulations and a phosphate supply shortage. Here, a new adsorption-membrane separation strategy was developed for rational reutilization of phosphate from sea cucumber aquaculture wastewater using a Zr-modified-bentonite filled polyvinyl chloride membrane. The as-obtained polyvinyl chloride/Zr-modified-bentonite membrane was highly permeability (940 L/(m²·h)), 1–2 times higher than those reported in other studies, and its adsorption capacity was high (20.6 mg/g) when the phosphate concentration in water was low (5 mg/L). It remained stable under various conditions, such as different pH, initial phosphate concentrations, and the presence of different ions after 24 h of adsorption in a cross-flow filtration system. The total phosphorus and phosphate removal rate reached 91.5% and 95.9%, respectively, after the membrane was used to treat sea cucumber aquaculture wastewater for 24 h and no other water quality parameters had been changed. After the purification process, the utilization of the membrane as a new source of phosphorus in the phosphorus-free f/2 medium experiments indicated the high cultivability of economic microalgae Phaeodactylum tricornutum FACHB-863 and 1.2 times more chlorophyll a was present than in f/2 medium. The biomass and lipid content of the microalgae in the two different media were similar. The innovative polyvinyl chloride/Zr-modified-bentonite membrane used for phosphorus removal and recovery is an important instrument to establish the groundwork for both the treatment of low concentration phosphate from wastewater as well as the reuse of enriched phosphorus in required fields.     

草莓有机与无机种植系统能流和经济流的比较研究

通过３年田间试验，比较分析了草莓有机与无机种植系统的能流、经济流及对土壤环境的影响。结果表明，有机系统草莓产量、经济效益均高于无机系统；有机系统能量产投比仅为无机系统的２５％，但投入的绝大部分为可再生能源；有机系统土壤有机质、微生物量高于无机系统，具有更好的土壤条件     

超临界水氧化处理高浓度丙烯酸废水

采用超临界水氧化（SCWO）技术在连续蒸发壁式反应器内处理高浓度丙烯酸废水。实验结果表明：SCWO能有效地处理丙烯酸废水,废水COD和TOC去除率分别达到99％左右,且反应时间短;反应温度、反应压力和氧化剂加入量的增加有利于COD和TOC去除率的提高。实验得出的废水处理最佳工艺条件：反应温度693K、反应压力24～26MPa、氧化剂加入量1．0～1．5倍。对反应器出口试样进行色谱-质谱联用分析结果表明,小分子醇、醚类以及CO2和CO是主要的液相产物和气相产物。针对腐蚀和盐沉积问题,提出了预防措施。     

基于余震序列分布信息的地震极灾区快速判断方法研究

利用震级加权标准差椭圆法研究了基于震后短期内(24 h)余震序列判定地震极灾区的方法,研究结果表明:1利用该方法判断宏观震中是一种比较可行的方法,不同震源破裂方式的震例利用该方法判断宏观震中的精度不同,倾滑-近倾滑型破裂方式的震例利用余震序列判定宏观震中的精度最高;2整体上看,利用该方法判断极灾区长轴方向的准确性低于利用距震中最近活动断裂判断的准确性,但对于倾滑-近倾滑型破裂方式的震例,利用该方法的准确性高于利用断层数据判定的准确性。     

酸浸法回收制革污泥中的铬

利用硫酸酸浸提取制革污泥中的金属铬,研究了固液比、酸浓度、浸出时间、温度和搅拌速度等因素对浸出效率的影响,并获得最优浸出条件。结果表明,最优浸出条件为:固液比10g/L,硫酸浓度0.5mol/L,浸出温度50℃,浸出时间1.5h。搅拌速度对硫酸浸出铬影响较小。经硫酸二次浸出铬的效率达到90.95%。因此,用硫酸酸浸的方法提取制革污泥中的铬是可行的。     

地下渗滤处理村镇生活污水的中试

以红壤土作为填充土壤,在2cm/d的水力负荷下,进行了地下渗滤系统处理村镇生活污水的现场中试.结果表明,地下渗滤系统对COD、氨氮、总磷和总氮有着良好的去除效果,去除率分别达到84.7%、70.0%、98.0%和77.7%,出水COD、氨氮、总磷和总氮的平均浓度分别为11.7mg/L、4.0mg/L、0.04mg/L、4.7mg/L,达到建设部颁发的生活杂用水水质标准对总氮去除机理的分析表明,由硝化/反硝化实现生物脱氮是地下渗滤系统去除总氮的主要途径.在本中试系统中,反硝化效果良好但硝化效果不够理想,改善土壤环境以促进硝化作用是提高总氮去除率的关键.对土壤中氧化还原电位的测定结果表明,土壤内部的还原性质是阻碍硝化反应进行的主要原因.     

糠醛渣对水中甲基橙的吸附性能

为了探究糠醛生产中的废料糠醛渣对水体中甲基橙的吸附性能和吸附机制,利用FT-IR（傅里叶变换红外光谱）和SEM（扫描电镜）对糠醛渣的结构特性进行表征,浅析糠醛渣对甲基橙的吸附机制;通过模拟试验,考察了吸附剂用量、pH、吸附时间和温度等因素对糠醛渣吸附甲基橙过程的影响;采用吸附动力学模型和吸附等温模型,进一步探讨了糖醛渣吸附机制.结果表明:①糠醛渣结构疏松多孔,表面具有丰富的官能团,有利于吸附.②糠醛渣能高效吸附水中甲基橙,在温度为293 K、pH为4~9、吸附剂用量为0.2 g时,糠醛渣对400 mg/L的甲基橙吸附效果最好;吸附过程在60 min左右达到平衡,并且较好地符合准二级动力学模型（R2=0.999 9）;吸附量随温度的升高而减少,表明该吸附过程为放热过程;在293 K时最大理论吸附量为54.35 mg/g,吸附数据更符合Langmuir吸附等温模型（R2=0.993 3）,表明糠醛渣对甲基橙的吸附主要为单层吸附.③糠醛渣可再生重复利用,吸附甲基橙后的糠醛渣用0.1 mol/L氢氧化钠溶液进行解吸再生试验,第5次使用时对甲基橙仍然具有较好的吸附效果.研究显示,糠醛渣在室温条件下、较宽的pH范围内能快速高效地吸附水中的甲基橙,并且重复利用性好,是一种在偶氮染料废水处理中具有发展前景的廉价、可再生生物质吸附材料.      

Effect of ozone injection on the long-term performance and microbial community structure of a VOCs biofilter

For biofilters treating waste gases containing volatile organic compounds(VOCs), biomass accumulation is a common problem which will induce bed clogging and significant decrease in VOCs removal efficiency during long-term operation. In this study, ozone injection was developed as a biomass control strategy, and its effects on the biofilter performance and the microbial community structure were investigated in long-term operation. Two biofilters,identified as BF1 and BF2, were operated continuously for 160 days treating gaseous toluene under the same conditions, except that 200 mg/m3 ozone was continuously injected into BF1 during days 45–160. During the operation period, ozone injection did not change the toluene removal efficiency, while the pressure drop of BF1 with ozone injection was significantly lowered compared with BF2. The wet biomass accumulation rate of BF1 was 11 g/m~3/hr, which was only46% of that in BF2. According to the carbon balance result, ozone injection also increased the toluene mineralization rate from 83% to 91%, which could be an important reason for the low biomass accumulation. The PMA-q PCR result indicated that ozone injection increased the microbial viability of the biofilm. The high-throughput sequencing result also revealed that the dominant phyla and genera were not changed significantly by ozone injection, but some ozonetolerant genera such as Rhodanobacter, Dokdonella and Rhodococcus were enhanced by ozone exposure. All the results verified that ozone injection is capable of sustaining the long-term performance of biofilters by lowering the biomass accumulation, increasing the microbial viability and changing the microbial community structure.