Modelling the thresholds of nitrogen/phosphorus concentration and hydraulic retention time for bloom control in reclaimed water landscape

● A new model for bloom control in open land scape water was constructed. ● It considers the effects of temperature and light on algae growth. ● It describes threshold curve of nitrogen, phosp horus and hydraulic retention time. ● Light and temperature dependent growth para meters of typical algae were obtained. The risks posed by algal blooms caused by nitrogen and phosphorus in reclaimed water used in urban water landscapes need to be carefully controlled. In this study, the combined effects of the nitrogen and phosphorus concentrations and the light intensity and temperature on the specific growth rates of algae were determined using Monod, Steele, and Arrhenius models, then an integrated algal growth model was developed. The algae biomass, nitrogen concentration, and phosphorus concentration mass balance equations were used to establish a new control model describing the nitrogen and phosphorus concentration and hydraulic retention time thresholds for algal blooms. The model parameters were determined by fitting the models to data acquired experimentally. Finally, the control model and numerical simulations for six typical algae and mixed algae under standard conditions were used to determine nitrogen/phosphorus concentration and hydraulic retention time thresholds for landscape water to which reclaimed water is supplied (i.e., for a reclaimed water landscape).     

青弋江流域不同级别河流底栖动物群落结构研究

2013年8月对青弋江流域不同级别河流底栖动物进行了调查。共采集到底栖动物60种，隶属于39科58属。从1级到4级河流，种类数表现出逐渐减少的趋势，分别为46、39、36和16种。1~3级河流中种类数最多的均是水生昆虫，4级河流中种类数最多的是软体动物。整个流域底栖动物密度和生物量分别为382 ind./m2和3643 g/m2。不同级别河流中，2级河流底栖动物密度最大，4级河流密度最小，且二者存在显著差异；2级和4级河流底栖动物生物量都较高，且显著高于1级河流。在功能摄食类群方面，整个流域以刮食者和过滤收集者为主。随着河流级别的增加，刮食者相对密度和相对生物量表现出先增加后下降的趋势；撕食者在1、2级河流所占比例较高；直接收集者和过滤收集者在1级和4级河流中所占比例较高     

羟基磷灰石去除废水中的Fe3+

以天然磷矿粉制备的羟基磷灰石(HAP)作为吸附剂，处理模拟含Fe3+废水。实验结果表明，在HAP加入量为1.0g/L、初始模拟废水pH为3.00、反应温度为室温的最佳条件下，处理初始Fe3+质量浓度为150mg/L的模拟废水，反应90min后Fe3+去除率为99.89%，处理后模拟废水中Fe3+质量浓度为0.15mg/L，低于0.30mg/L，达到GB5749—2006《生活饮用水卫生标准》的要求。     

滤布滤池强化处理城市二级出水中试研究

采用滤布滤池对南方某城市污水处理厂二级出水进行强化处理中试研究，以达到中水回用的目的。实验选用氯化铁(FeCl₃)、聚合氯化铝铁（PAFC）和聚合氯化铝（PAC）作为强化滤布滤池除磷效果的混凝剂。当不投加混凝剂时，滤布滤池对TP和COD的平均去除率为28.76%和8%，其中TP的去除效果受进水水质影响较大；当投加氯化铁、聚合氯化铝铁与聚合氯化铝强化滤布滤池时，滤布滤池对TP的平均去除率分别为63.58%、60.13%和66.94%，TP去除效果受进水水质影响较小；对SS的平均去除率分别为70.7%、64.3%和49.1%；对COD平均去除率分别为17.7%、26.3%和27.7%。滤布滤池对TN和NH₃-N去除效果不稳定。     

Scaled-up bioconversion of fish waste to liquid fertilizer using a 5 L ribbon-type reactor

A scaled-up conversion process of fish waste to liquid fertilizer was performed in a 5 L ribbon-type reactor. Biodegradation was performed by inoculation of autoclaved fish waste with 5.84 × 10(5) CFU mL(-1) of mixed microorganisms for 96 h. As a result, the pH changed from 6.92 to 5.72, the cell number reached 7.28 × 10(5) CFU mL(-1), and approximately 430 g (28.3%) of fish waste was degraded. Analyses indicated that the 96 h culture of inoculated fish waste possessed comparable fertilizing ability to commercial fertilizers in hydroponic culture with amino acid contents of 6.91 g 100 g(-1). Therefore, the scaled-up production achieved a more satisfactory fish waste degradation rate (3.61 g h(-1)) than the flask-scale production (0.24 g h(-1)). The biodegraded broth of fish waste at room temperature did not undergo putrefaction for 6 months due to the addition of 1% lactate.     

华北农牧交错带夏季降水变率及其与前期下垫面热力状况的关系

华北农牧交错带夏季降水有很大的变率 ,频繁的干旱对农牧业生产有严重影响。论文分析了1880年以来的夏季降水变化特征 ,近百年来农牧交错带夏季降水有明显的阶段性。功率谱分析显示有35年左右的周期。年代际尺度的波动是干湿变化的重要背景。以250mm等雨量线表示的农牧交错带南北位置也有明显的年际和年代际的变化 ,在1978年以前和以后的两段时期 ,平均位置有显著的差别 ,前后平均有大约1.5个纬度的变化。农牧交错带夏季降水与前期春季亚欧地区大范围的温度异常有较好的关系。印度和巴基斯坦及相邻印度洋地区是显著的正相关区 ;亚洲西部的内陆地区是显著的负相关区。这两个地区春季的温度能解释农牧交错带夏季降水方差的15 %左右。     

水利水电建设工程生态环境质量定量评价体系研究

依据国家有关法律和法规 ,根据水利水电建设项目工程的特点 ,提出了一个综合反映水利水电建设工程生态环境质量定量评价体系 ,它从一系列指标的客观实测值或估算值与该指标在生态环境中的主观环境质量评价等级两者间建立评价体系 ,并根据拟建水库的生态环境效应判别并运用特尔菲法确定各指标的权重。     

Ecologically based management of rodents in the real world: applied to a mixed agroecosystem in Vietnam.

Rodents cause significant damage to lowland irrigated rice crops in the Red River Delta of Vietnam. A four-year study was conducted in 1999-2002 to examine the effectiveness of applying rodent control practices using the principles of ecologically based pest management. Four 100-150 ha study sites adjacent to villages were selected and farmers on two treated sites were asked to follow a set of rodent management practices, while farmers on the untreated sites were asked not to change their typical practices. Farmers on the treated sites were encouraged to use trap-barrier systems (TBS's; 0.065-ha early planted crop surrounded by a plastic fence with multiple capture traps; one TBS for every 10-15 ha), to work together over large areas by destroying burrows in refuge habitats soon after planting (before the rats reestablish in the fields and before the onset of breeding), synchronizing planting and harvesting of the their rice crops, cleaning up weeds and piles of straw, and keeping bund (embankment) size small (<30 cm) to prevent burrowing. A 75% reduction in the use of rodenticides and plastic barrier fences (without traps or an early crop) was achieved on treated sites. The abundance of rodents was low after implementation of the management practices across all sites. There was no evidence for an effect of treatment on the abundance of rodents captured each month using live-capture traps, and no difference in damage between treatments or in yields obtained from the rice crops. Therefore, ecologically based rodent management was equally effective as typical practices for rodent management. Farmers on the treated sites spent considerably less money applying rodent control practices, which was reflected in the comparative increase in the partial benefit:cost of applying ecologically based rodent management from 3:1 on treated sites and untreated sites prior to the implementation of treatments to 17:1 on treated sites in the final year of the project.     

Manure phosphorus extractability as affected by aluminum- and iron by-products and aerobic composting

Shifts in manure phosphorus (P) chemical forms and pool sizes induced by water treatment residuals and industrial mineral by-products are largely undefined. We conducted a manure P fractionation study to determine mechanisms of reduction of dissolved reactive phosphorus (DRP) in poultry manure upon mineral by-product additions. The effects of composting on the P immobilization efficacy of the by-products were determined using laboratory self-heating composting simulators. The mineral by-products included an aluminum-water treatment residual (Al-WTR) and an iron-rich titanium-processing by-product. The noncomposted manure averaged 0.11 g g(-1) of total P as DRP forms. The by-products significantly reduced manure DRP, by an average of 39 and 48% in the Al- and the Fe-treated manure, respectively. The by-products also reduced the 0.5 M NH4F-extractable phosphorus (FEP) fraction. Shifts in P forms between FEP and 0.1 M NaOH-extractable phosphorus (SHEP) depended upon the Al and Fe contents of the by-products while the combined FEP + SHEP pool remained constant. Phosphate sorption measurements supported the observations that the Fe-rich by-product was more effective at reducing manure DRP and enhancing the formation of SHEP forms at the expense of FEP than the Al-WTR. Composting had no effect on the efficacy of either by-product to reduce DRP. Potential mechanisms of enhanced P stabilization in treated manure upon composting included chemical shifts from the DRP and FEP fractions to the citrate-bicarbonate-dithionite extractable P fraction. Thus, the choice of P immobilization agents affected the stability of immobilized P forms and should be taken into consideration in developing manure processing and nutrient stabilization methods.