Construction of an Ecological Ditch Based on Periphyton Reactor

[Objective] This study aimed to make the effluent of constructed wetlands in a pond recirculating aquaculture system satisfy aquaculture requirements. [Method] A 150 m long, 0.5 m wide and 0.6 m deep ecological ditch was constructed on the basis of the periphyton reactor theory, to investigate the reoxygenation and deep purification effect of the ecological ditch on the effluent of constructed wetlands. [Result] Experimental results showed that the level of dissolved oxygen （DO） in the effluent of constructed wetlands increased to a range of 4.41-7.91 mg/L and pH val- ue increased significantly by flowing though the ecological ditch （P〈0.05）. DO level in the water of ecological ditch increased linearly with the increasing length of the ecological ditch within the range of 150 m （P〈0.05）. The ecological ditch showed further removal effect on NH4＋-N, IMn and PO4^3 -P in the effluent of the constructed wetlands, with the removal rate of 19.46%, 13.38% and 31.09%, respectively. The total coliform group was also eliminated with the removal rate ranging between 12.5% and 78.13%. [Conclusion] The ecological ditch based on periphyton reactor could improve DO level and further reduce N and P contents in the effluent of the constructed wetlands, which could be used as a matching water-reuse system of constructed wetlands. Key words Water quality; Purification; Dissolved oxygen; Periphyton; Pond aquaculture

Water Quality Purifying Effect of Five Kinds of Aquatic Plants in Winter

[Objective] The aim was to compare the water quality purifying effect of five kinds of aquatic plants.[Method] Model of surface flow wetlands was constructed in the river bank of Jialu River in Zhengzhou City,and five kinds of aquatic plants which could grow normally in winter were selected and introduced for screening experiment of aquatic plants.[Result] Five kinds of plants were growing well,and they showed strong cold resistance.However,there were some differences on water quality purifying ability among five kinds of aquatic plants,in which Oenanthe javanica and Elodea canadensis performed better on removing the TN,the removal rate was 44% and 41% respectively; Iris sibirica and O.javanica showed better performance on the removal of TP,the removal rate was 41% and 37% respectively; there was little difference on the removal effect on NH4^＋-N among five kinds of plants,in which E.Canadensis performed best with the removal rate of 73%,followed by O.javanica （the removal rate was 71%）,and the removal rate of I.sibirica,Rumex acetosa and Potamogeton crispus were 70%; there was no significant purification effect of five kinds of plants on CODCr,in which I.sibirica and R.acetosa performed better,and the removal rate was 14% and 13% respectively.[Conclusion] The emerging plants and submerged plants hydrophytes could be used to construct floating aquatic macrophyte-based treatment system （FAMS） in wetland vegetation allocation to improve the purification effect of wetlands of North China in winter.

Effects of Combinations of Two of Three Different Probiotics on Pond Water Quality

In order to provide reference for probiotics application in aquaculture, Bacillus subtilis （A）, Streptococcus faecalis （B） and photosynthetic bacteria （C） were prepared according to the ratios of 9：1, 4：1, 1：1, 1：4 and 1：9 with 10^5 cfu/ml as the unit of concentration into 15 mixed microecological preparations, and their effects on COD, ammonia nitrogen, nitrite nitrogen and sulfide in pond water were investigated. The results showed that the mixed preparation of B. subtilis and photosynthetic bacteria at a ratio of 1：4 had the best effect in treating COD （P〈0.05）, the mixed preparation of B. subtilis and S. faecalis at a ratio of 4：1 showed the best effect in treating ammonia nitrogen （P〈0.05）, the mixed preparation of S. faecalis and photosynthetic bacteria at a ratio of 4：1 showed the best effect in treating nitrite nitrogen （P〈0.05）, and the mixed preparation of Streptococcus faecalis and photosynthetic bacteria at a ratio of 9：1 had the best effect of reducing sulfide （P〈0.05）.

Surface flow constructed wetland with composite plant bed for pretreatment of micro-polluted Yellow River raw water in China

In order to investigate the feasibility of pretreating the micro-polluted Yellow River raw water by constructed wetland, an experiment was conducted using a surface flow constructed wetland with composite plant bed. The contamination removal efficiency and their trends in the wetland treatment system were studied under different hydraulic loading rates(HLR). The contamination removal efficiencies were compared according to the seasonal change under optimum HLR. The result shows that in the same season, under different hydraulic loadings ranging from 2 to 6 m3/(m2·d) at the same period, the best HLR is 4 m3/(m2·d) in the experimental system. The average removal rates of COD, TN, ammoniacal nitrogen(NH4+-N), and TP in the constructed wetland are 38.37%, 45.97%, 39.86% and 41.69%, respectively. According to China Standard for Surface Water Resources (GB3838-2002), mean effluent of COD, TN, NH4+-N and TP can nearly reach Grade Ⅲ, GradeⅤ, GradeⅠand GradeⅠ, respectively. Furthermore, treatment efficiency of the system in summer is obvious higher than that in other seasons. The expenditure of constructing the constructed wetland with the average treating capacity of 176 m3/d and lifetime of 20 years is 17075.00 RMB. The average disposal cost is summed up to 0.17 RMB/m3, which shows that the pretreatment of the micro-polluted Yellow River raw water by constructed wetland is feasible.

Effects of Self-purification of River Water on Laundry Wastewater

[Objective] This study was conducted to investigate the effect of laundry wastewater on the quality of river water and the dilution purification effect of river water on laundry wastewater. [Method] The effects of laundry wastewater on the contents of total nitrogen(TN), total phosphorus(TP), suspended solids(SS), chemical oxygen demand(COD) and linear alkylbenzene sulfonic acid(LAS) were studied in 7 rivers of Shaoxing City. [Result](1) The contents of TN, TP, SS, COD and LAS increased by 92%, 99%, 340%, 351% and 923%, respectively, at the discharging moment of laundry wastewater; and(2) the five pollutional indexes significantly decreased over time, and especially 2 h after the discharge of laundry wastewater, compared with former the discharge of laundry wastewater, the contents of TN, TP, COD and LAS increased by 6%, 11%, 9% and13%, respectively,while the contents of SS still increased by 76%, i.e., SS required a longer time to achieve self-purification. [Conclusion] Laundry wastewater has some influence on thequality of river water, and the self-purification function of river water could effectively remove pollutants.

水生植物与生态环境关系

伴随着我国经济社会发展取得的巨大成就,我国环境破坏日趋严重,人们的生存环境恶化,水污染也特别严重。水生植物可以吸收污染水体中的富营养元素和有毒元素,达到净化水质的效果。利用这一特性,可以通过较小的成本达到很好的治理效果。现在,许多国家都在致力研究水生植物改善水质、维持生态平衡的具体方法。我国也在不断地探索之中。

Analysis of the influence of collection purification filtration system of channel upon groundwater quality about freeway

At present, it is usually used the method that elevating the height of embankment to design passages of freeway to avoid transverse traffic disturbance in plain areas of China. But when design low embankment, it is difficulty for drainage or setting passages and culverts. Hengshui to Darning freeway in Hebei provence （Heng-Da freeway） is one section of Dalian to Guangzhnu freeway. This paper analyzes the characteristic of climate, geology, hydrology and low water table, good permeability stratum soil and its little and mass rain fall and deep drinking water well in the plain areas of North China when design low embankment of Heng-Da freeway, puts forward the drainage methods of water collecting filtration system to solve the drainage problem of passages and culverts, aiming at the type and the measures of the pollution on the surface, the channel collection purification infiltration system of highway uses the single composite technology of aerobic and oxygen to digest - precipitation-absorption of artificial materials percolation of soil to deal with the pollution of the rain on the road （the composite technology use the vermiculite as the material of infiltration）, which be controlled in the drinking range of the water standard. It not only efficiently solved the problem of water collected in the channel, but also supplied the groundwater. It has reached the environment-friendly road construction purpose of the sustainable development of highway construction, ＂environment friendly＂ and ＂resource conservation＂.

Eco-compensation in Guanting Reservoir Watershed Based on Spatiotemporal Variations of Water Yield and Purification Services

Guanting Reservoir（GR） is one of the most important water sources for Beijing and neighboring regions.Due to water pollution,it was withdrawn from the system to supply Beijing drinking water;however,after a thorough treatment process,GR was made a reserve water source since 2007.To develop a comprehensive and quantitative analysis of water yield and purification services in the GR watershed,this study selected two time periods：the period when GR was withdrawn from the system supplying local drinking water and the period that it has been designated a reserve water source.The In VEST model was used to evaluate the quantities of water yields,and total nitrogen and total phosphorus outputs from 1995 to 2010 Additionally,the spatiotemporal variations of water yield services and water quality purification services in the GR watershed were analyzed.The results showed that water yield services in the GR watershed first weakened and then became stronger,but weakened overall during the years 1995 to 2010.Water yield capacity in the basin decreased from 1.89×10^9 m3 in 1995 to 1.43×10^9 m3 in 2010（a drop of 24.0% in total）.Water quality purification services also showed the same tendency.Total nitrogen output decreased from 4028.7 t in 1995 to 3611.4 t in 2010,while total phosphorus decreased from 379.7 t in 1995 to 354.0 t in 2010.Nitrogen and phosphorus purification services were enhanced by 10.4% and 6.8%,respectively.Changes in the climate and land use were the main factors which lead to the changes in the water yield service in the GR watershed.Policies intended to protect water resource have matched the varying trends of water quality purification services during different periods.On one hand,the research results provide a foundation to identify key fields for eco-compensation in the Guanting Reservoir basin.On another hand,the ecosystem service value will increase on the basis of eco-compensation criteria through setting the scenarios of returning farmland to forest and ecological protection.This method directly reflects increases in ecosystem service values that have occurred since measures to protect the ecological environment have been implemented.This method is more persuasive and feasible than using eco-compensation criteria based on regional ecosystem service values determined by land use/coverage type.It can provide a new way to assess eco-compensation in the Guanting Reservoir basin and other regions.

Progress in the studies of low-molecular mass gelators with unusual properties

This article is intended to provide an overview of recent progress in the studies of cholesterol-based low-molecular mass gelators (LMMGs) with unusual properties,in particular,gelation and selective gelation at room temperature,gel emulsions and gel film formation,etc.Potential applications of the LMMGs in spilled oil collection and water purification are briefly presented.

Intensive photocatalytic activity enhancement of Bi5O7I via coupling with band structure and content adjustable BiOBrxI1-x

Band structure and component content are the key factors for determining the activity of semiconductor heterojunction. In this study, a novel Bi5O7I/BiOBrxI1-x heterostructure was synthesized by a simple hydrobromic （HBr） acid etching method through transforming partial of Bi5O7I to I ion doped BiOBr （BiOBrxI1-x） at room temperature without adding extra dopant. Both the band structure and component content of Bi5O7I/BiOBrxI1-x alter with the additive HBr acid. The Bi5O7I/BiOBrxI1-x （S3.0） sample exhibits the best photocatalytic activity, 6 times higher than that of pure Bis071, for the degradation of methyl orange under visible-light （2 〉 420 nm）. The activity enhancement of Bi5O7I/BiOBrxI1-x is primarily ascribed to the improved separation efficiency of photocharges, originated from the adjustable band structure and component content, The significant findings of this paper provide a facile way to construct highly efficient semiconductor heterojunction via playing the synergetic effect of adjustable band struc- ture and component content for purifying organic pollutants in wastewater.

Simulation and evaluation of the water purification function of Zhalong Wetland based on a combined water quantity-quality model

The water purification function of natural wetland systems is widely recognized,but rarely studied or scientifically evaluated.Extensive studies have been carried out by various international wetland research communities to quantify the water quality improvement ability of the natural wetlands,in order to maintain such ability and wetland ecological health.This study aims to evaluate the purification function of Zhalong Wetland in China for removing total nitrogen(TN) and phosphorus(TP),based on ex-situ experiments and the development of a combined water quantity-quality model.Experiments and model predictions were carried out with different input TP and TN concentrations.Statistical analyses demonstrated that the relative errors between model simulations and experimental observations for TN and TP were 8.6% and 12.4%,respectively.With water retention time being maintained at 90 d,the removal rate of these pollutants could not reach the required Grade V standards,if the inflow TN concentration was over 42 mg L-1,or the input TP concentration was over 14 mg L-1.The simulation results also demonstrated that,even with Grade V quality standard compliance,when the water inflow from surrounding industries and agriculture lands into Zhalong Wetland reaches 0.3×10 8 m 3 a-1,the maximum TN and TP loads that the reserve can cope with are 1.26×10 3 t a-1 and 0.42×10 3 t a-1,respectively.Overall,this study has produced a significant amount of information that can be used for the protection of water quality and ecological health of Zhalong Wetland.