香根草和风车草人工湿地对猪场废水氮磷处理效果的研究

分别以香根草 (Vetiveriazizanioides )和风车草 (Cyperusalternifolius)为植被 ,按 1.0m× 0 .5m×0 .8m建立人工湿地 ,通过四季测试研究其对猪场废水N、P的净化功能及其随季节、进水浓度及水力停留时间变化的规律 .结果表明 ,两湿地对NH3 N和S PO3 -4 去除率受污水停留时间和污水浓度影响较大 .香根草或风车草人工湿地在春季对NH3 N和S PO3 -4 有明显的去除效果 ;在秋季 ,则对去除废水TN均有效果 ,在去除TP上 ,香根草湿地效果明显 ,风车草湿地效果差 .秋春季人工湿地随水力停留时间 (t)延长 ,TP或S PO3 -4 (Y)的去除遵从指数方程Yt=Y0 ·e-kt规律 .冬季和夏季 ,进水浓度对湿地去除P影响较大 ;在相同停留时间内 ,冬夏季人工湿地随进水浓度变化 ,进出水S PO3 -4 遵从直线方程 y =a +bx规律     

Effects of plants and microorganisms in constructed wetlands for wastewater treatment

Constructed wetlands are a natural alternative to technical methods of wastewater treatment. However, our understanding of the complex processes caused by the plants, microorganisms, soil matrix and substances in the wastewater, and how they all interact with each other, is still rather incomplete. In this article, a closer look will be taken at the mechanisms of both plants in constructed wetlands and the microorganisms in the root zone which come into play when they remove contaminants from wastewater. The supply of oxygen plays a crucial role in the activity and type of metabolism performed by microorganisms in the root zone. Plants' involvement in the input of oxygen into the root zone, in the uptake of nutrients and in the direct degradation of pollutants as well as the role of microorganisms are all examined in more detail. The ways in which these processes act to treat wastewater are dealt with in the following order: Technological aspects; The effect of root growth on the soil matrix; Gas transport in helophytes and the release of oxygen into the rhizosphere; The uptake of inorganic compounds by plants; The uptake of organic pollutants by plants and their metabolism; The release of carbon compounds by plants; Factors affecting the elimination of pathogenic germs.     

红树林湿地有机碳研究进展

红树林湿地是地球上生产力最高的区域之一,尽管红树林的面积相对较少,但其单位面积的固碳能力很强,是重要的"蓝碳"碳库,其有机碳储量及动态对于全球碳平衡有重要影响。本文对红树林湿地有机碳(包括植被生物量碳和沉积物有机碳)的碳储量及计量方法,沉积物中有机碳的组成、来源及溯源方法,以及影响红树林湿地有机碳动态的因素等方面的研究进行了综述,并对其存在的问题和今后的研究趋势进行了分析。基于红树林湿地的固碳潜力和资源快速减少的现状,准确评估红树林碳库及其动态,有助于气候变化框架条约下的滨海湿地碳计量和价值评价,可以揭示红树林生态系统与全球变化的反馈关系,为红树林生态恢复和保护提供依据。     

Effects of bleaching wastewater irrigation on soil quality of constructed reed wetlands

Constructed reed wetland microcosms (CRWs) in a lab of east China have been irrigated with bleaching wastewater per month for a reed growth season. The soil physicochemical properties, enzyme activities (i.e. urease, invertase, polyphenol oxidase, alkaline phosphatase and cellulase) and soil microbial diversity were assayed before and after the exposure experiment. Compared to the river water irrigated controls (CKs), bleaching wastewater application has no marked influence on soil pH, but significantly increased soil Na⁺, total halogen and absorbable organic halogen (AOX) contents, which induced the increasing of soil electrical conductivity. Furthermore, soil enzyme activities displayed significant variation (except for polyphenol oxidase). Bleaching wastewater irrigation decreased Sorenson’s pairwise similarity coefficient (C_s), which indicated the changes of the structure of bacterial and fungal communities. However, only the diversity of bacterial community was inhibited and has no effect on the diversity of fungal community, as evidenced by the calculated Shannon–Wiener index (H).     

人工湿地处理炼油废水的生态效益研究

来自茂名石化公司的炼油废水含有较高浓度的污染物 ,超过广东省规定的排放标准 ,未经处理不能直接排放。 4种草本植物 ,香根草、芦苇、宽叶香蒲和蒲草被用来测试建植人工湿地的效果以及所建植的人工湿地处理炼油废水的效果。在为期 2个月的处理过程中 ,人工湿地在前期对炼油废水的净化效率很高 ,它们对第一批高浓度废水中氨氮、COD、BOD和油的去除率分别是 97.7%、78.2 %、91 .4%和 95 .3% ,对第一批低浓度污水分别是 97.1 %、71 .5 %、73.7%和 89.8%。但是 ,随着时间的推移 ,湿地的净化效果会有一定程度的下降 ,然后逐渐趋于稳定。湿地对氨氮、COD、BOD和油类的去除效率始终表现为氨氮 >油类 >BOD>COD,但植物对它们的净去除量却是 COD>BOD>氨氮和油类。湿地建植之初 ,植物的净化功能很弱 ,但随植物的生长和生物量的增加而逐渐增强。然而 ,不同植物种对废水的净化率很接近 ,基本上无显著性差异。被测试的 4种植物在污水湿地中的生长表现都好过在清水湿地中的 ,但香根草、芦苇和宽叶香蒲在高浓度废水的分蘖数比在低浓度的废水少些 ,而蒲草相反 ,表明高浓度污水相对于低浓度污水而言已经对前面 3个种产生了伤害 ,却仍促进蒲草生长。在清水培养阶段 ,香根草产生分蘖的速度是 4个种中最低的 ;进入污水培养阶     

Designing constructed wetlands for reclamation of pretreated wastewater and stormwater

Wastewater reclamation is getting greater attention as an alternative to conventional approaches to wastewater treatment and water supply due to increasing water stress coupled with more stringent water quality limitation for discharge of treated wastewater. Among the few technologies adopted in the field for wastewater reclamation, constructed wetlands have been used to reclaim both primary and secondary treated wastewater in regions with arid and humid climates. This paper summarizes the widely adopted guidelines that need to be considered when designing constructed wetlands for wastewater reclamation, discusses the capacity of wetland treatment systems for water reuse while assessing the status of full-scale constructed wetlands designed for wastewater reclamation, and develops contaminant loading charts as a design tool based on the performance of existing full-scale constructed wetlands deployed for wastewater reclamation. It is evident that constructed wetland systems provide a viable means to treat wastewater to the levels required for low-quality reuses such as restricted irrigation and impoundment. It is challenging for constructed wetlands to consistently meet microbiological guidelines for high-quality reuses such as unrestricted agricultural and urban reuses. Wastewater reclaimed through constructed wetlands is used mainly for agricultural and landscape irrigation, groundwater recharge, indirect potable reuse, and environmental reuse. Surface area and hydraulic loading rate of constructed wetlands to be deployed for wastewater reclamation can be estimated with contaminant loading charts derived from monitoring data of existing full-scale operations.     

Treatment of dairy wastewater using constructed wetlands and intermittent sand filters

In Ireland, the most common method of disposal of dairy parlour washings is by land spreading. This treatment method has numerous problems, namely high-labour requirements and the potential for eutrophication of surface and ground waters. Constructed wetlands are commonly used for treatment of secondary municipal wastewaters and they have been gaining popularity for treatment of agricultural wastewaters in Ireland. Intermittent sand filtration may offer an alternative to traditional treatment methods. As well as providing comparable treatment performance, they also have a smaller footprint, due to the substantially higher organic loading rates that may be applied to their surfaces. This paper discusses the performance and design criteria of constructed wetlands for the treatment of domestic and agricultural wastewater, and sand filters for the treatment of domestic wastewater. It also proposes sand filtration as an alternative treatment mechanism for agricultural wastewater and suggests design guidelines.     

Treatment of olive mill wastewater in pilot-scale vertical flow constructed wetlands

Pilot-scale constructed wetlands (CW) were constructed and operated to treat pre-treated olive mill wastewater. Pilot-scale units comprising three identical series with four pilot-scale vertical flow CWs were operated for one harvest season in a Greek olive mill plant. The pilot-scale CWs were filled with various porous media (i.e., cobble, gravel, and sand) of different gradations. Two series of pilot-scale units were planted with common reeds and the third (control) was unplanted. Mean influent concentrations were 14,120 mg/L, 2841 mg/L, 95 mg/L, 123 mg/L and 506 mg/L for COD, phenols, ortho-phosphate, ammonia and TKN, respectively. Despite the rather high influent concentrations, the performance of the CW units was very effective since it achieved removals of about 70%, 70%, 75% and 87% for COD, phenols, TKN and ortho-phosphate, respectively. COD, phenol and TKN removal seems to be significantly higher in the planted series, while ortho-phosphate removal shows no significant differences among the three series. Temperature and pollutant surface load seem to affect the removal efficiency of all pollutants. Compared to previous studies, pollutant surface loads applied here were higher (by one or two orders of magnitude). Even though high removal efficiencies were achieved, effluent pollutant concentrations remained high, thus preventing their use for irrigation or immediate disposal into the environment.     

Rehabilitation by constructed wetlands of available wastewater treatment plant in Sakhnin

In rural areas, insufficient wastewater treatment often causes serious environmental problems, especially for human health. Due to this problem, new wastewater treatment plants (WWTP) should be constructed or upgraded. When considering economic and maintenance factors, constructed wetlands (CWs) are more desirable processes. The available WWTP located in the Northern Israeli town of Sakhnin was redesigned and upgraded. To rehabilitate the WWTP, six new CWs having different operating conditions were constructed as a pilot project. The most appropriate place of construction of the CWs was thought to be at the end of the WWTP. From the beginning of the system, inlet and outlet pollution parameters such as chemical oxygen demand (COD), ammonia (NH₄-N⁺), total suspended solids (TSS), and phosphorus (PO₄-P³⁻) were monitored in the CWs from August 2005 to February 2006. As a result the most appropriate CWs were found having Phragmites as plant and volcanic tufa as media material. The maximum removal efficiencies were 71.8% on COD, 92.9% on TSS, 63.8% on ammonia for CW5 tank. Adversely, phosphorus removal was not so high in CW5. Phosphorus removal was negligible in the study.     

Hybrid constructed wetlands for wastewater treatment and reuse in the Canary Islands

The performance of two substrates commonly available in the zone, gravel and lapilli, was tested for their use in hybrid constructed wetland pilot plants for the treatment and reuse of urban wastewater in Gran Canaria, Canary Islands, Spain. The first stage of the systems was a vertical subsurface-flow constructed wetland and the second stage was a horizontal subsurface-flow constructed wetland. Parallel experiments were carried out with one system containing only crushed stone basaltic gravel as substrate and the other with only lapilli, a very porous volcanic sediment. The comparative effect of substrate type, hydraulic loading rate and planting was studied.Tracer studies indicated that the experimental TRHs were significantly lower than the theoretical ones, particularly for the vertical flow with gravel. Though the vertical flow with lapilli performed better than the one with gravel, the hybrids showed quite similar removals.Planting or varying the hydraulic loading rate introduced little differences between the vertical flows or the hybrids. Average removals for the gravel-based hybrid constructed wetland were 86% for BOD, 80% for COD, 88% for ammonia-N, 96% for SS and turbidity, 24% for phosphate-P, and 99.5% for faecal coliforms and 99.7% for faecal enterococci. Thus, it can be concluded that hybrid constructed wetlands proved to be robust configurations for wastewater treatment in the Canary Islands.     

人工湿地污水处理技术问题及改进措施研究进展

人工湿地作为一种绿色生态、低成本的污水处理技术,其应用日渐广泛。随着应用和机理研究的深入,传统湿地在运行过程中也涌现出各种问题。本文总结了近几年来人工湿地污水处理所出现的堵塞、脱氮效率低、污染负荷小、受温度影响大等问题,综述了国内外学者针对这些问题采取的内部系统强化、工艺改进以及与其他工艺类型组合等措施,并对今后人工湿地技术的发展方向进行探讨。     

Performances of constructed wetlands for municipal wastewater treatment in rural mountainous area

A global performance evaluation of an experimental Horizontal SubSurface Flow Constructed Wetlands (HSSF) was made after 6 years of functioning. This wetland is situated in French prealpine mountain, at 720 m elevation. The HSSF process treatment consists in a three-stage system dimensioned for 350 People Equivalent. Different helophytes were planted such as Typha latifolia, Phragmites australis and Scirpus maritimus. The mean hydraulic residence time for sewage was closed to 4–5 days, but in summer the mean pollutant residence time increases to 6 days due to an important evapotranspiration. There is no clogging of the gravel matrix and the hydraulic conductivity was very good and stabilized. Removal pollutant efficiency was determinate at each stages. There was a high removal of total suspended solids (TSS) all year around with an average of 95.6% (±3.6). More than 80% of removal occurred in the first stage. Physical processes (decantation, filtration) associated with biological oxidation were the principal factors of this removal. For COD and BOD₅, removal efficiency in the first stage were close to 60% on average and more than 90% at the outlet of the wetland. These results are similar to those observed with SSFW in many cases. Influence of temperature seems very weak because there were no significant seasonal variations of the process efficiency. Minimum effluent quality standards (30 mg l^–1 TSS; 120 mg l^–1 COD; 40 mg l^–1 BOD₅) were always respected. In cold periods, nutrients uptake was reduced but remained up to 60% in average. Mean bacterial removal efficiency was about two order of magnitude (99%) but can reach up to five order of magnitude in summer. These cyclic variations follow a sinusoidal variation around an annual mean. Pollutants removals were correlated to their respective loadings and no limits has been observed except for nitrogen. These results confirm that SSFW, an ecotechnology, should be considered as an alternative to conventional treatment methods (activated sludge, fixed biofilm) for small communities even in mountainous area.     

Effects of monocot and dicot types and species richness in mesocosm constructed wetlands on removal of pollutants from wastewater

The effects of planting type and species richness on removal of BOD5, COD, nitrogen and phosphorus were studied in mesocosms with monocot alone (M), dicot alone (D) and mixed planting of M+D, where each planting type had four species richness levels. Above- and below-ground plant biomasses increased with the M and M+D species richness as shown by one-way ANOVA. The M+D type had the highest above-ground biomass, whereas the M type had the highest below-ground biomass among planting types. Carbon, nitrogen and phosphorus in the microbial biomass increased with the richness of the M and M+D type. Removals of BOD5, COD, inorganic P and total P did not change with the richness, but removals of NH4-N, NO3-N increased. Planting type impacted only removal of inorganic P, with higher removal of inorganic P in the M type.     

Nitrogen mass balance and microbial analysis of constructed wetlands treating municipal landfill leachate

Experiments were conducted to investigate the feasibility of applying constructed wetlands to treat a sanitary landfill leachate containing high nitrogen and bacterial contents. Under a tropical condition (temperature of about 30 degrees C), the constructed wetland units operating at the hydraulic retention time of 8d yielded the best treatment efficiencies with BOD(5), TN and fecal coliforms removal of 91%, 96% and more than 99%, respectively. Cadmium removal in the SFCW bed was 99.7%. Mass balance analysis, based on total nitrogen contents of the plant biomass and dissolved oxygen and oxidation-reduction potential values, suggested that 88% of the input total nitrogen were uptaken by the plant biomass. Fluorescence in situ hybridization results revealed the predominance of bacteria, including heterotrophic and autotrophic, responsible for BOD(5) removal. Nitrifying bacteria was not present in the constructed wetland beds.     

The potential for constructed wetlands for wastewater treatment and reuse in developing countries: a review

Constructed wetlands are among the recently proven efficient technologies for wastewater treatment. Compared to conventional treatment systems, constructed wetlands are low cost, are easily operated and maintained, and have a strong potential for application in developing countries, particularly by small rural communities. However, these systems have not found widespread use, due to lack of awareness, and local expertise in developing the technology on a local basis. This paper summarizes information on current methods used for wastewater treatment in developing countries, and briefly gives basic information on wetlands. The paper further examines the potential of constructed wetlands for wastewater treatment and reuse in developing countries by looking at the results of current research initiatives towards implementation of the technology in these countries. Future considerations in choosing constructed wetlands as wastewater treating systems in developing countries are highlighted.     

Adaptation of wastewater surface flow wetland formulae for application in constructed stormwater wetlands

Over the past 30 years, the use of constructed wetlands for wastewater treatment has been a topic of significant research culminating in a good data base from which simplistic equations have been derived to aid in the design of these facilities to meet long term water quality treatment performance criteria. Over the past decade, the use of treatment wetlands has extended to stormwater and combined sewer overflow (CSO) management applications. Designing constructed wetlands for stormwater and CSO applications have unique challenges stemming from the highly stochastic nature of the hydraulic and pollutant loading on a stormwater wetland compared with wastewater treatment systems. This paper explores the possibility of adapting the simplistic models for wastewater wetlands for interim use in developing design guidelines for stormwater wetland systems. A procedure that takes into account the unsteady intermittent nature of stormwater inflows to these wetlands has been incorporated into one of these simplistic models and a case study presented to demonstrate the application of the procedure.     

Anaerobic ammonium oxidation in sediments of surface flow constructed wetlands treating swine wastewater

Applied Microbiology and Biotechnology - Anaerobic ammonium oxidation (anammox) was suggested to be involved in the nitrogen (N) removal process in constructed wetlands (CWs). Nevertheless, its...