矿物材料吸附去除污水中磷的试验研究

采用粉煤灰、高岭土、泥渣(取电厂澄清池排泥作脱水干燥处理)作为吸附剂深度处理污水中的磷,对比分析了3种吸附剂的吸附速度、吸附性能及除磷效果。结果表明:粉煤灰和高岭土用时20 min完成对磷的有效吸附,沉降泥渣用时5 min即可实现同等吸附效果;沉降泥渣对污水中磷的吸附能力较好,投加量为0.2 g/L的泥渣对磷的去除率可达98.1%,而投加量为0.2 g/L粉煤灰或高岭土对磷的去除率仅达到77.2%。     

浅议影响污水生物除磷的因素

针对目前水体富营养化严重，污水除磷要求高的现状，着重分析阐述了在目前条件下的对污水生物除磷产生较显著影响的因素，如，溶解氧及氧化还原电位，硝酸盐，泥龄，进水营养比等，以期对生产实践有所帮助。     

钙镁磷肥对土壤中镉形态转化与水稻吸镉的影响

酸性镉污染水田施用不同用量的钙镁磷肥的田间试验表明:土壤中交换态镉的分配系数随钙镁磷肥用量的增加而降低,呈显著负相关(r,-0.9314);碳酸盐结合态和铁锰氧化物结合态镉的分配系数则呈显著正相关(r,0,9395)。而土壤中有效态镉含量与钙镁磷肥用量则呈显著负相关(r,-0.8853)。镉污染水田一次性投加高量钙镁磷肥后,可使土壤pH显著升高,交换态镉分配系数明显下降,碳酸盐结合态和铁锰氧化物结合态镉分配系数明显升高,导致土壤中有效态镉含量大幅度下降,从而大大减少水稻植株的吸镉量。     

磷肥厂烘干磨高压静电除尘技术及应用

本文根据高压静电除尘的原理,磷肥厂烘干磨粉尘的特性分析,以及作者本人的工作实践,探讨了高压静电除尘技术在磷肥厂烘干磨粉尘治理中应用的可行性。     

Remediation of copper-contaminated topsoils from a wood treatment facility using in situ stabilisation

Five organic matters, three phosphate compounds, zerovalent iron grit (ZVIG, 2% by soil weight), two alkaline compounds, and two commercial formulations were incorporated, singly and some combined with ZVIG, into a highly Cu-contaminated topsoil (Soil P7, 2600 mg Cu kg⁻¹) from a wood treatment facility. Formulations and two composts were also singly incorporated into a slightly Cu-contaminated topsoil (Soil P10, 118 mg Cu kg⁻¹) from the facility surrounding. This aimed to reduce the labile pool of Cu and its accumulation in beans cultivated on potted soils in a climatic chamber. Lowest Cu concentration in soil solution occurred in P7 soils amended with activated carbon (5%) and ZVIG, singly and combined. Basic slag (3.9%) and compost of sewage sludge (5%) combined with ZVIG promoted shoot production and limited foliar Cu accumulation. For amended P10 soils, no changes occurred in soil solution and foliar Cu concentrations, but one compost increased shoot production.     

Nutrient pathways and their susceptibility to past and future change in the Eurasian Arctic Ocean

Climate change is altering nutrient cycling within the Arctic Ocean, having knock-on effects to Arctic ecosystems. Primary production in the Arctic is principally nitrogen-limited, particularly in the western Pacific-dominated regions where denitrification exacerbates nitrogen loss. The nutrient status of the eastern Eurasian Arctic remains under debate. In the Barents Sea, primary production has increased by 88% since 1998. To support this rapid increase in productivity, either the standing stock of nutrients has been depleted, or the external nutrient supply has increased. Atlantic water inflow, enhanced mixing, benthic nitrogen cycling, and land–ocean interaction have the potential to alter the nutrient supply through addition, dilution or removal. Here we use new datasets from the Changing Arctic Ocean program alongside historical datasets to assess how nitrate and phosphate concentrations may be changing in response to these processes. We highlight how nutrient dynamics may continue to change, why this is important for regional and international policy-making and suggest relevant research priorities for the future.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01673-0.     

A regulatory perspective on the radiological impact of NORM industries: the case of the Spanish phosphate industry

Radioactive and chemical risks coexist in NORM industries although they are usually addressed separately by regulations. The European Union (EU) has developed extensive legislation concerning both matters, which has been diversely reflected in national policies. We consider the case of the Spanish phosphate industry and analyse to which extent regulatory mandates have reduced the historical and ongoing radiological impact on the environment of phosphate facilities. Although no specific radiological constraints on effluent monitoring and release or on waste disposal have yet been imposed on NORM industries in Spain, other environmental regulations have achieved a substantial reduction on the phosphate industry impact. Nevertheless, a more efficient control could be established by eliminating the current conceptual and practical separation of chemical and radioactive risks in NORM industries. We highlight research needs to accomplish so and propose shorter-term measures that require active cooperation among the regulatory bodies involved.     

Arsenic strongly associates with ferrihydrite colloids formed in a soil effluent

Arsenic mobility may increase in liquid phase due to association with colloidal Fe oxides. We studied the association of As with Fe oxide colloids in the effluent from water-saturated soil columns run under anoxic conditions. Upon exfiltration, the solutions, which contained Fe²⁺, were re-aerated and ferrihydrite colloids precipitated. The entire amount of effluent As was associated with the ferrihydrite colloids, although PO₄³⁻, SiO₄⁴⁻, CO₃²⁻ and dissolved organic matter were present in the effluent during ferrihydrite colloid formation. Furthermore, no subsequent release of As from the ferrihydrite colloids was observed despite the presence of these (in)organic species known to compete with As for adsorption on Fe oxides. Arsenic was bound via inner-sphere complexation on the ferrihydrite surface. FTIR spectroscopy also revealed adsorption of PO₄³⁻ and polymerized silica. However, these species could not impede the quantitative association of As with colloidal ferrihydrite in the soil effluents.     

Accelerated seeded precipitation pre-treatment of municipal wastewater to reduce scaling

Membrane based treatment processes are very effective in removing salt from wastewater, but are hindered by calcium scale deposit formation. This study investigates the feasibility of removing calcium from treated sewage wastewater using accelerated seeded precipitation. The rate of calcium removal was measured during bench scale batch mode seeded precipitation experiments at pH 9.5 using various quantities of calcium carbonate as seed material. The results indicate that accelerated seeded precipitation may be a feasible option for the decrease of calcium in reverse osmosis concentrate streams during the desalination of treated sewage wastewater for irrigation purposes, promising decreased incidence of scaling and the option to control the sodium adsorption ratio and nutritional properties of the desalted water. It was found that accelerated seeded precipitation of calcium from treated sewage wastewater was largely ineffective if carried out without pre-treatment of the wastewater. Evidence was presented that suggests that phosphate may be a major interfering substance for the seeded precipitation of calcium from this type of wastewater. A pH adjustment to 9.5 followed by a 1-h equilibration period was found to be an effective pre-treatment for the removal of interferences. Calcium carbonate seed addition at 10 g l⁻¹ to wastewater that had been pre-treated in this way was found to result in calcium precipitation from supersaturated level at 60 mg l⁻¹ to saturated level at 5 mg l⁻¹. Approximately 90% reduction of the calcium level occurred 5 min after seed addition. A further 10% reduction was achieved 30 min after seed addition.     

内江市磷肥厂磷矿石,磷肥样品中天然铀,镭—226含量分析

本文报道了内江市８个磷肥的磷肥及其原料矿石中天然铀，＾２２６Ｒａ含量水平，其结果为，磷肥样品中＾２２６Ｒａ含量２４５．８±１１２．９Ｂｑ．ｋｇ＾－１，天然铀含量２７．２±１６．４ｐｐｍ；磷矿石样品中＾２２６Ｒａ含量４０７．６±９４．３Ｂｑ．ｋｇ＾－１，天然铀含量３１．４±２１．０ｐｐｍ。