Biodegradation of thermally synthesized polyaspartate

Polyaspartate synthesized using thermal methods (thermal polyaspartate; TPA) has been shown to have dispersant and crystallization inhibition activities. These activities suggest that the polymer may be used in water treatment and paper processing and as a detergent and paint additive. The commercial potential for TPA is enhanced by the fact that it may be synthesized on a large scale. Therefore, a study of the biodegradation of the polymer was undertaken. TPA was produced by hydrolysis of a polysuccinimide synthesized by dry thermal polymerization of aspartic acid. The resulting polymer was a poly(,-dl-aspartate) having a 70% structure and containing a racemic mixture of aspartic acid. TPA was incubated with both dilute effluent and activated sludge from a wastewater treatment plant. Low-biomass effluent experiments showed changes in molecular size of TPA concomitant with oxygen demand induced by the polymer, suggesting susceptibility of TPA to at least partial biodegradation. Low-biomass sludge experiments (SCAS, modified Sturm) yielded approximately 70% mineralization of 20 mg L^–1 TPA by 28 days, suggesting that a significant portion of the polymer was labile. High-biomass sludge experiments using¹⁴C-TPA at 1 mg L^–1 revealed approximately 30% mineralization and 95% total removal of TPA carbon from solution in 23 days, with most of the mineralization and removal taking place in less than 5 days. Additional short-term studies using a variety of particulate substrates, including activated sludge, confirmed that TPA is subject to removal from solution by adsorption. From these studies with labeled TPA, it was concluded that TPA is subject to rapid removal and at least partial degradation in a wastewaster treatment plant. Using gel and thin-layer chromatography, it was determined that at least part of the unmineralized residue from the high biomass assays was polyaspartate. It is speculated that the unusual structure of TPA compared to natural proteins may limit the rate of proteolysis of the polymer and thus its overall degradation rate.     

Implementation of failure modes and effects analysis in detergent production companies: A case study

Failure mode and effect analysis (FMEA) is the most important method used by production companies to identify potential risks regarding occupational and health hazards and environmental hazards. This method is also useful in defining preventive actions to reduce the effects of these risks. Detergent production companies continually encounter many occupational and health hazards and environmental hazards, the management and reduction of which requires complex assessment in real‐world applications. This paper presents a framework for application of FMEA for managing and ranking identified risks in detergent production companies. A case study is presented to show the application of an FMEA to investigate the results of its application and the outcomes from the analysis. A risk priority number (RPN) is proposed for each distinct risk. The application of FMEA in the detergent production company resulted in grouping the RPN of the identified risks into four different categories. The main corrective actions, which are determined to reduce the RPNs, are presented in this paper. Improving the RPN of the main risks is observed after executing the corrective actions.     

合成洗涤剂生产废水处理技术

采用混凝法对高浓度合成洗涤剂生产废水进行预处理,去除废水中大量的SS、油脂类物质及表面活性剂,出水与其他低浓度废水混合进行生物氧化处理。试验结果表明,混凝气浮法对COD、SS及油脂类物质去除效果明显,COD去除率为35％－56％;在废水含盐量较高的情况下,生物氧化法仍有较高的处理效率,COD去除率达到70％－95％。     

TILE RATIONALE FOR OHIO'S DETERGENT PHOSPHORUS BAN1

ABSTRACT: Ohio signed into law a detergent phosphorus ban on March 26, 1988. This law limits the elemental phosphorus content of household laundry detergents to 0.5 percent in all 35 Lake Erie counties in Ohio by 1990. Ohio's detergent phosphorus ban will help non-compliant municipal wastewater treatment plants achieve compliance with the 1 mg/L effluent phosphorus standard. By limiting the phosphorus content of household laundry detergents, Ohio will also benefit from less phosphorus entering surface waters from combined sewer overflows, communities with treatment plant bypasses, and riparian homes with septic tanks. This is important because most of the phosphorus in laundry detergents is in the bioavailable form and Ohio's Lake Erie shoreline is particularly sensitive to Cladophora problems. When viewed in conjunction with reduced chemical costs for phosphorus removal and savings in sludge disposal costs, Ohio's detergent phosphorus ban is a pragmatic component of an international phosphorus management strategy to protect the Great Lakes.     

用PVA包埋法固定化细胞去除洗衣粉废水中LAS的研究

经富集培养得到降解LAS的细菌菌系,在24小时内可将40—50mg/L的LAS分解90％以上。用PVA-硼酸化法包埋该菌系得到的固定化细胞,在处理洗衣粉废水中LAS时的最适pH为5.35—7.70,最适温度为25℃—35℃。在1L反应器中的间歇式连续运行表明:PVA小球/废水(V/V)=30％,进水LAS 40—70mg/L,HRT=3h条件下,LAS去除率可达90％以上。     

浅谈阴离子洗涤剂测定中应注意的几个问题

水质监测中,采用亚甲蓝分光光度法测定水中的阴离子,由于方法的选择性较差,干扰因素及操作过程中出现的问题也颇多,本文就阴离子测定中干扰消除及分析操作过程中应注意的问题进行讨论。     

无患子餐具洗涤剂的研制

制备了由表面活性剂和助剂组成的餐具洗涤剂,并通过试验法确定其最佳原料配比,对所配洗涤剂的去污能力进行了测定。结果表明,该产品制备简便、综合洗涤性能较好,具有较高的应用价值。     

BCO+BAF工艺深度处理洗涤剂废水

采用生物接触氧化(BCO)+曝气生物滤池(BAF)组合工艺深度处理洗涤剂废水,研究了溶解氧浓度(DO)、水力停留时间(HRT)对其处理性能的影响。实验结果表明,随着DO浓度的提高,组合工艺对COD和LAS的去除率都随之增加;水力停留时间的增加有利于对COD与LAS的去除,最佳停留时间选为21.2h为宜;在BCO段DO为3.0 mg/L,HRT为20.0 h,BAF段DO为4.0 mg/L,HRT为1.2 h的运行条件下,COD与LAS的去除率分别为90.5%和94.3%,出水COD和LAS均能达到排放标准。     

氯氧化锆废弃物制备层状硅酸钠的研究

以氯氧化锆生产中排放的废弃物碱性废水和酸性硅渣为主要原料制备了层状硅酸钠。研究了不同工艺条件下样品的基本性能。结果表明,碱性废水和酸性硅渣为主要原料,可制备出性能良好的层状硅酸钠。其晶型主要为δ型,钙离子交换容量（CEC）可达270 mg/g,pH在11～12之间,完全满足洗涤助剂的基本要求。此方法为氯氧化锆废弃物的综合利用提供了一条新途径。     

洗涤剂对水环境的风险及防控对策建议

随着我国经济社会的快速发展和人民生活水平的不断提高,新兴有毒有害污染物的排放使流域水环境污染风险不断加大,严重影响水环境安全。以洗涤剂中的抗菌剂三氯生(triclosan,TCS)和三氯卡班(triclocarban,TCC)为研究对象,梳理了其来源和毒性;并以东江流域为例开展研究,分析TCS在水-沉积物中的检出率及分布特征。结果表明:TCS和TCC在东江流域水体中最大浓度分别为168和269 ng/L,在悬浮物中最大浓度分别为297和431 ng/L,在沉积物中最大浓度分别为656和2 723 μg/kg,TCS和TCC已成为东江流域主要的高风险化学物质。关注流域环境风险物质,推动我国生态洗涤,尽可能减少新兴有毒有害污染物对人体和水环境的影响是当前流域水环境风险管理的主要任务之一。