垂直流人工湿地出水口位置与植物种类对农村生活污水净化效果的影响

利用3 种栽种植物的美人蕉(Canna indica Linn)湿地(M)、狼尾草[Pennisetum alopecuroides (Linn.) Spreng]湿地(L)、苏丹草[Sorghum sudanense (Piper) Stapf]湿地(S)和未栽种植物的对照湿地(CK), 研究高、中、低出水口及不同植物对垂直流人工湿地污水净化效果的影响。垂直流人工湿地进水来自常熟农业生态试验站生活污水厌氧池, 以间歇式进水方式运行, 进水水力负荷为0.15 m³·m^-2·d^-1。结果表明: 不同出水口位置对NH₄⁺-N(铵态氮)、NO₃^--N(硝态氮)、COD(化学需氧量)的去除率存在显著性差异。随着出水口位置的降低NH₄⁺-N 的去除率显著增加, 最大去除率达到98.3%。出水口位置升高NO₃^--N 与COD 的去除率则显著增加, 高出水口的去除率分别达到-47.4%和64.5%。与中、低出水口处理相比, 高出水口的TN(总氮)去除率提高22.5%~27.6%。而对TP(总磷)的去除率恰恰相反, 高出水口处理TP 去除率比中、低出水口低20.6%~28.9%。3 种有植物湿地—美人蕉湿地、狼尾草湿地、苏丹草湿地对NO₃^--N、TN、TP、COD去除率显著高于未栽种植物的对照湿地, 分别提高74.4%~98.6%、11.3%~17.8%、8.60%~16.3%与14.1%~19.0%。3 种植物湿地之间对NO₃^--N、TN、TP、COD 去除效果没有显著差异。对NH₄⁺-N 的去除效果, 美人蕉湿地显著低于其他3 种湿地。以上结果表明, 通过对垂直流人工湿地的出水口位置控制和栽种湿地植物,可以有效地改变污染物的去除效果。     

基于人工湿地的循环水产养殖系统工艺设计及净化效能

该研究首次将复合垂直流人工湿地同池塘养殖结合，通过构建养殖－湿地生态系统，验证人工湿地对水产养殖用水和废水净化与回用的可行性。近9个月的新建人工湿地运行结果表明，水力负荷从313、469、625 mm/d增加到781 mm/d，人工湿地对TSS、COD_Cr和BOD₅去除率的变动范围分别为80.5%～82.9%、45.2%～64.2%和61.0%～77.0%，对NH^＋₄-N、NO^-₃-N、TN去除率的变动范围分别为51.5%～67.8%、-90.6%～40.0%和29.1%～68.6%，对TP和IP的去除率为72.7%～89.1%和0～33.3%，对细菌总数、总大肠菌群、藻类等生命物质也有较好的去除效果，湿地出水水质除溶氧外能达到国家渔业水质标准。初步结果表明人工湿地应用于水产养殖用水处理和回用具有广阔的前景。     

模拟潜流人工湿地处理猪场废水的实验研究

采用盆栽试验模拟潜流型人工湿地，研究了土壤、蛭石、煤渣和碎石四种人工湿地基质不同组合净化养猪场污水的能力。结果表明：以上层蛭石土混合物、下层煤渣和碎石的组合处理效果最佳，14d内COD_Cr、NH₄⁺-N、T-P的去除率分别达到了95.3%、90%、91.6%。试验前期，四种不同组合基质的COD_Cr、NH₄⁺-N、T-P去处率有明显差异，但试验后期除T-P的去除率仍有明显差异外，COD_Cr和NH₄⁺-N去除率已无明显差异。     

膜生物反应器处理猪场污水研究

为探讨膜生物反应器(MBR)处理猪场污水的可行性和膜生物反应器的运行、操作条件，为膜生物反应器在处理猪场污水中的应用提供必要的基础参数，该文采用U型中空纤维膜和L式中空纤维膜生物反应器，对不同的化学需氧量(COD)及氨氮(NH⁺₄-N)进水浓度、溶解氧水平(DO)、污泥龄(SRT)进行了4种工况试验研究。结果表明，MBR作为猪场污水处理好氧段是可行的，当进水COD平均浓度为1860 mg/L，U型、L式膜平均去除率分别为84.10％，81.20％；NH⁺₄-N进水平均浓度为511 mg/L，U型、L式膜平均去除率分别为93.81％，93.61％。     

畜禽舍粪便污水及废气净化的研究

猪场污水经文中所述工艺系统处理以后,污水中的化学耗氧量(COD_Cr)达到98.4mg/L;生物需氧量(BOD₅)达到49.6mg/L;悬浮物(SS)达到51.49mg/L以下;硫化物达1.0mg/L以下:铜和铜化物达到0.6mg/L以下。畜舍中的废气净化,选择挥发性的药材制成“姜满净化剂”,能使畜舍的氨(NH₃)降解率达到73.9％,舍内含氟量为15.0mL/m³;硫化氢(H₂S)降解率达到85.8％,舍内的硫化氢浓度为2.8mL/m³;细菌降低率达到70.7％。     

去污和苗圃功能兼具的美人蕉漂浮植物修复系统研究

利用泡沫塑料作为漂浮栽培系统在猪场氧化塘废水中种植美人蕉，通过根系的吸收和吸附等作用，去除废水中的N、P元素，降低废水中的COD_Cr浓度，并通过美人蕉在猪场废水中快速生长的特性，来探讨美人蕉对废水的净化效果和修复系统作为快速育苗的苗圃的可行性。结果表明，美人蕉在猪场废水中生长良好，生物量大，根系发达，经美人蕉漂浮栽培之后废水中的N、P元素去除效果显著，废水中总氮、总磷和COD_Cr的去除率均在90%左右，每株美人蕉在废水中生长35 d的平均分蘖数为2.5个，每年的分蘖数可达20～25个，是作为苗圃快速育苗的良好方法。     

改进型和传统型复合垂直流人工湿地的净化效果研究

通过构建传统型复合垂直流人工湿地系统（IntegratedVerticalFlowConstructedWetlandsSystem：IVFCWS）和改进型复合垂直流人工湿地系统（ImprovedIntegratedVerticalFlowConstructedWetlandsSystem：IIVFCWS）,并在其中分别种植彩叶草-太阳草（Coleusblumei-Toninafluviatilis：CT）和美人蕉-大水剑（Cannaindica-Acoruscalamus：CA）,以无植物人工湿地系统为对照,比较研究不同植物组合下两种构型的人工湿地系统对生活污水的净化效果。结果表明,IIVFCWS对CODCr、NH4＋-N、TN的净化效果显著优于IVFCWS,而对TP的去除效果则是IVFCWS较IIVFCWS强。有植物的人工湿地系统去除污染物的效果较无植物的对照系统好,其中彩叶草-太阳草组合湿地系统的去除效果较美人蕉-大水剑组合的强,分别为：CODCr的平均去除率在80．8％-52．8％之间;NH4-N的去除率在93．6％-52．3％之间;TN的去除率在96．4％～67．6％之间,TP的平均去除率均达93．6％以上。     

集约化猪场废水强化生化处理工艺试验研究

该文采用新型厌氧反应器技术和强化生物脱氮及硝化技术处理猪场废水。试验结果表明：新型厌氧反应器容积COD_Cr负荷可达8 kg/(m³·d)以上，稳定运行COD_Cr平均去除率为75％；生物脱氮及硝化采用一体式A/O反应器，缺氧段水力停留时间为1 h，好氧段水力停留时间为3 d，氨氮浓度可控制在10 mg/L以下。总出水COD_Cr平均550 mg/L，BOD₅平均53.0 mg/L，NH₃-N平均8.8 mg/L，总COD_Cr去除率87%，总BOD₅去除率96%，NH₃-N总去除率在98％以上；采用原水碳源优化分配强化生物脱氮，TN去除率为77.11%左右。总出水BOD₅/COD_Cr约0.10，出水COD_Cr中难生物降解成分占绝大多数，需经过后续物化处理才能达到广东省水污染物控制标准(DB44/26-2001)。     

杭州灯塔养殖总场猪粪污水处理工程的设计与运行

采用厌氧—好氧(UASB—SBR)法处理技术对杭州灯塔养殖总场的高浓度猪粪污水进行处理，COD总去除率达98%，NH₃-N去除率达99%以上，出水COD浓度不大于150 mg/L ，NH₃-N浓度不大于15 mg/L，出水水质达到《污水综合排放标准》(GB8978-1996)的二级排放标准。     

王家庄滨湖人工湿地去除农业径流中COD效果的测试与分析

研究处理农业径流的滨湖人工湿地中有机物(COD_Cr，化学需氧量)的去除规律可为类似湿地的设计和运行提供参考。该研究报道了滇池东岸王家庄湿地(占地12000 m²)自2002年8月投入运行后23个月中的有机物去除的季节变化规律。该湿地的优势植物种为茭草(Zizania caduciflora)和芦苇(Phragmites australis)，5条农业区汇水干渠的来水经过布水堰布水后均匀地流过湿地。2002年10月～2004年6月期间,湿地表现出较好的拦截沟渠来水中有机物的能力,有效地降低了滇池的外源有机物污染负荷。旱季(每年11月～翌年4月)和雨季(每年5月～10月)的平均流量分别为497.6 m³/d和747.4 m³/d。进水COD_Cr的负荷为36.1 g/(hm²·d)(旱季)和67.9 g/(hm²·d)(雨季),COD_Cr的平均浓度为87.1 mg/L(旱季)和109 mg/L(雨季)。COD_Cr的出水平均浓度为45.1 mg/L以下(旱季)和53.7 mg/L(雨季)，分别满足一级A标准和一级B标准(城镇污水处理厂污染物排放标准，GB 18918-2002)。运行期间的平均水温为旱季17.3℃,雨季21.9℃，COD_Cr的平均去除率为48.2%以上(旱季)和51.0%(雨季)。旱季和雨季湿地中COD_Cr浓度沿程降低，旱季和雨季2/3流程处的COD浓度均低于1/3流程处,农业径流可生化性较差导致湿地中前段的COD降解不明显。旱季湿地的出水受滇池水返混的影响比雨季的大,因此旱季1/3处和2/3处之间的浓度差小。湿地表层土壤(0～40 cm)的pH值沿程升高,有机质沿程降低。     

Ion input/output budgets for five wetlands constructed for acid coal mine drainage treatment

Five wetlands, each 6 m wide and 30 m long and containing 30 cm of an organic substrate (Sphagnum peat to which limestone and fertilizer were surface-applied on a quarterly basis, Sphagnum peat, sawdust, straw/manure, spent mushroom compost), were exposed to controlled inputs of acid coal mine drainage (AMD; pH 2.89, soluble Fe, Mn, and SO₄ ^2? concentrations of 119, 19, and 3132 mg L^?1, respectively) at a mean flow rate of 8513 L da^?1 for 111 weeks, beginning in July of 1989. All wetlands were net sources, rather than sinks, for base cations (Ca²⁺, Mg²⁺, Na⁺, K⁺). The Sphagnum peat wetland was the least effective in treating the AMD, retaining 35% of the soluble Fe influx, but not retaining substantial H⁺, soluble Mn, soluble Al, SO₄ ^2?, or acidity. The straw/manure and mushroom compost wetlands were the most effective in treating the AMD, retaining 53 and 67% of the H⁺ influx, 80 and 78% of the soluble Fe influx, 7 and 20% of the soluble Mn influx, 54 and 53% of the soluble Al influx, 15 and 11% of the SO₄ ^2? influx, and 57 and 63% of the acidity influx. For these two wetlands especially, treatment effectiveness was substantially diminished during the cold winter months of January through March. Moreover, from March through July of the final year of the study, treatment effectiveness was minimal with outflow pH and concentrations of soluble Fe, Mn, Al, SO₄ ^2? and acidity that were similar to inflow values. Decreases in treatment effectiveness over time appeared to be related to a decrease in the ability to counter the substantial acid load entering the wetlands in the AMD. Lime or limestone dissolution and bacterial dissimilatory sulfate reduction may have contributed substantially to pH improvement and acidity consumption in the straw/manure and mushroom compost wetlands, but after 2 years the cumulative input of acidity apparently had overwhelmed biotic and abiotic alkalinity generating mechanisms, as reflected in a progressive decrease in both substrate pH and abiotic acid neutralization capacity (ANC) over time, especially in the surface substrates. Also over time, effluent H⁺ and acidity concentrations became more like influent and H⁺ and acidity concentrations. Although samples of wetland interstitial water were not collected for chemical analysis, as substrate pH and ANC decreased and as influent and effluent water chemistry became more similar, it is likely that wetland interstitial water became progressively more acidic, potentially inhibiting bacterial processes that could contribute to effective treatment, favoring dissolution rather than formation of insoluble metal precipitates, and thereby contributing to the eventual failure of the wetlands to effectively treat the AMD. In general, when constructed wetlands are used to treat particularly acidic (pH<4) AMD, if abiotic and biotic alkalinity generation cannot balance the influent acid load, long-term effective treatment will not be achieved.     

Alkalinity generation by Fe(III) reduction versus sulfate reduction in wetlands constructed for acid mine drainage treatment

Despite the widespread use of wetlands for acid mine drainage (AMD) treatment, alkalinity generating mechanisms in wetlands and their abiotic and biotic controls are poorly understood. While both dissimilatory sulfate reduction and Fe(III) reduction are alkalinity-generating mechanisms, only the former has been considered as important in wetlands constructed for AMD treatment. This study was conducted to determine the extent to which Fe(III) reduction occurs and the extent to which sulfate reduction versus Fe(III) reduction contributes to alkalinity generation in 5 wetlands constructed with different organic substrates (Sphagnum peat with limestone and fertilizer, Sphagnum peat, sawdust, straw/ manure, mushroom compost) that had been exposed to the same quality and quantity of AMD for 18–22 months. These substrates had Fe oxyhydroxide concentrations of 250–810 μmol Fe g^?1 dry substrate. Flasks containing 100 g of wet substrate along with either 150 mL of wetland water or 130 mL of wetland water and 20 mL of 37 % formalin were incubated at 4 °C in January and 25 °C in May. On days 0, 2, 4, 8, 12 and 16, the slurry mixtures were analyzed for concentrations of H⁺, Fe²⁺ and SO₄ ^2?. The bulk of the evidence indicates that for all except the mushroom compost wetland, especially at 25 °C, biologically-mediated Fe(II) reduction occurred and generated alkalinity. However, in none of the wetlands, regardless of incubation temperature, was there evidence to support net biological sulfate reduction or its attendant alkalinity generation. Sulfate reduction and concurrent Fe(III) oxyhydroxide accumulation may be important in the initial stages of wetland treatment of AMD, both contributing to effective Fe retention. However, as Fe(III) oxyhydroxides accumulate over time, Fe(III) reduction could lead not only to decreased Fe retention, but also to the potential net release of Fe from the wetland.     

湖北省鄂州市湿地净初级生产力及固碳释氧量估算

[目的] 估算湖北省鄂州市净初级生产力(net primary productivity,NPP)以及固碳释氧量,探索一种适用于中小尺度上,涉及大量水体的湿地NPP估算方法,为制定相关湿地生态保护政策提供更为准确的数据支撑。[方法] 构建湿地分类模型,将鄂州市湿地划分为浅水地表湿地与深水水体湿地。对浅水地表湿地,采用基于遥感影像的光能利用率模型进行NPP估算;对深水水体湿地,引入叶绿素a与生物量指标,构建回归模型,对湿地水体NPP进行估算。汇总两者的估算结果,得到鄂州市湿地2020年度NPP总量及其空间分布和固碳释氧量。[结果] 鄂州市湿地2020年度净初级生产力总量为2.99×10⁵ t (以C计),CO₂的固定量为4.87×10⁵ t,O₂的释放量为3.59×10⁵ t,整体上呈现南高北低的分布格局。[结论] 采用湿地分类的方法,对深水水体湿地NPP单独进行估算,弥补了基于遥感影像的模型估算方法中对湿地水体部分估算的不足,使估算结果更接近湿地真实水平,采用的模型方法可为类似涉及水体的湿地NPP估算工作提供一种新思路和方法。     

Efficiency of Mesocosm-Scale Constructed Wetland Systems for Treatment of Sanitary Wastewater Under Tropical Conditions

Subsurface-flow constructed wetlands technology (SSFW) has been used successfully for treating sanitary wastewater throughout North America and Europe. However, treatment wetland technologies have not been used extensively in the tropics. To advance tropical studies, a pilot-scale SSFW was constructed on the campus of the University of the Atlantic in Barranquilla, Colombia. The systems performance was monitored from January to July of 2009. The treatment system consisted of a 760-L septic tank followed by three mesocsom-scale subsurface-flow constructed wetlands in parallel arrangement. Clarified wastewater was batch loaded to each unit at a rate of 53 L/m²/day to affect a hydraulic retention time of approximately 3 days. One of the treatment units served as a non-planted control (gravel only), while the other two treatment units were planted with either Eriochloa aristata or Eleocharis mutata. The objective of this study was to evaluate the comparative efficacy of the treatment units (planted vs. unplanted), with respect to their abilities to augment treatment of septic tank effluent (sanitary wastewater). Monitored parameters included plant biomass, oxidation?Creduction potential, chemical oxygen demand (COD), temperature, dissolved oxygen, pH, ammonia?Cnitrogen (NH ₄ ⁺ ?CN) nitrate?C and nitrite?Cnitrogen (NO₃?CN, NO₂?CN), phosphates (PO ₄ ^? ), and coliform bacteria. Total biomass (dry matter) was 2.84 and 0.87 Kg/m² for E. aristata and E. mutata, respectively. Redox potential in the plant rizospheres averaged ?172 mV (±164.1) in E. aristata, 29 mV (±251.1) in E. mutata, and 32 mV (±210.5) in the unplanted control. COD removal was superior in planted vs. non-planted systems (>75% vs. 47%). Ammonia and total phosphorus removal averaged 69% and 85%, respectively, in planted systems versus 31% and 59% in the unplanted system. Removal of total and fecal coliforms averaged 96%. Results of this pilot study revealed that SSFW technology in the tropics can provide significant removal of organic matter, nutrients, and bacteria from clarified sanitary wastewater.     

Optimization of Petroleum Refinery Wastewater Treatment by Vertical Flow Constructed Wetlands Under Tropical Conditions: Plant Species Selection and Polishing by a Horizontal Flow Constructed Wetland

Typha latifolia-planted vertical subsurface flow constructed wetlands (VSSF CWs) can be used to treat petroleum refinery wastewater. This study evaluated if the removal efficiency of VSSF CWs can be improved by changing the plant species or coupling horizontal subsurface flow constructed wetlands (HSSF CWs) to the VSSF CW systems. The VSSF CWs had a removal efficiency of 76% for biological oxygen demand (BOD₅), 73% for chemical oxygen demand (COD), 70% for ammonium-N (NH₄⁺-N), 68% for nitrate-N (NO₃^?-N), 49% for phosphate (PO₄^3?-P), 68% for total suspended solids (TSS), and 89% for turbidity. The HSSF CWs planted with T. latifolia further reduced the contaminant load of the VSSF CW-treated effluent, giving an additional removal efficiency of 74, 65, 43, 65, 58, 50, and 75% for, respectively, BOD₅, COD, NH₄⁺-N, NO₃^?-N, PO₄^3?-P, TSS, and turbidity. The combined hybrid CW showed, therefore, an improved effluent quality with overall removal efficiencies of, respectively, 94% for BOD₅, 88% for COD, 84% for NH₄⁺-N, 89% for NO₃^?-N, 78% for PO₄^3?-P, 85% for TSS, and 97% for turbidity. T. latifolia strived well in the VSSF and HSSF CWs, which may have contributed to the high NH₄ ⁺-N, NO₃^?-N, and PO₄^3?-P removal efficiencies. T. latifolia-planted VSSF CWs showed a higher contaminant removal efficiency compared to the unplanted VSSF CW. T. latifolia is thus a suitable plant species for treatment of secondary refinery wastewater. Also a T. latifolia-planted hybrid CW is a viable alternative for the treatment of secondary refinery wastewater under the prevailing climatic conditions in Nigeria.     

Treatment of Domestic Wastewater by Three Plant Species in Constructed Wetlands

Three common Appalachian plant species (Juncus effusus L., Scirpus validus L., and Typha latifolia L.) were planted into small-scale constructed wetlands receivingprimary treated wastewater. The experimental design includedtwo wetland gravel depths (45 and 60 cm) and five plantingtreatments (each species in monoculture, an equal mixture of the three species, and controls without vegetation), with two replicates per depth × planting combination. Inflow rates (19 L day^-1) and frequency (3 times day^-1) were designed to simulate full-scale constructed wetlands as currently used for domestic wastewater treatmentin West Virginia. Influent wastewater and the effluent from each wetland were sampled monthly for ten physical, chemical and biological parameters, and plant demographic measurements were made. After passing through these trough wetlands, the average of all treatments showed a 70% reduction in total suspended solids (TSS) and biochemical oxygen demand (BOD), 50 to 60% reduction in nitrogen (TKN), ammonia and phosphate, anda reduction of fecal coliforms by three orders of magnitude. Depth of gravel (45 or 60 cm) had little effect on wetland treatment ability, but did influence Typha and Scirpus growth patterns. Gravel alone provided significant wastewater treatment, but vegetation further improved many treatment efficiencies. Typha significantly out-performedJuncus and Scirpus both in growth and in effluent quality improvement. There was also some evidence that the species mixture out-performed species monocultures.Typhawas the superior competitor in mixtures, but a decline in Typha growth with distance from the influent pipe suggested that nutrients became limiting or toxicities may have developed.     

利用有机覆盖物处理的人工湿地外排焦化废水研究

[目的]为进一步降低污染物浓度,提高钢铁企业水资源循环利用率。[方法]采用水平潜流人工湿地处理外排焦化废水,通过监测分析进出水中浊度、化学需氧量(COD),总氮(TN)和总磷(TP)含量,探讨冬季人工湿地植物层不添加及添加有机覆盖物对钢铁企业外排焦化废水净化水平的影响。[结果]在低温季节,水力停留时间为5d时,不添加有机覆盖物人工湿地对外排焦化废水浊度,COD,TN和TP的平均去除率分别为68.55%,14.94%,14.20%和71.26%;添加有机覆盖物人工湿地对外排焦化废水浊度、COD,TN和TP的平均去除率分别为72.54%,21.62%,20.50%和71.88%;有机覆盖膜的保温作用使得COD去除率升幅达44.68%,TN去除率升幅达44.45%。[结论]在植物层添加有机覆盖物作为保温材料,可以提高人工湿地在低温条件下的净化效率。     

构建功能性人工湿地处理养殖场废水

为寻求一种经济实用的养殖废水处理途径，人工湿地废水处理工艺越来越引起关注。该文综述了近几年来人工湿地处理机理、人工湿地的建造参数、人工湿地的作用及人工湿地的管理等，从生态系统的尺度展望了功能性人工湿地建构和多类污染物的联合去除的前景，期望在未来的人工湿地处理工艺的研究中关于养殖场废水处理的研究得到更切实的关注和更实质的进展，为动物养殖业的清洁生产做出贡献。     

几种挺水植物净化生活污水总氮和总磷效果的研究

研究了石菖蒲、灯心草和蝴蝶花3种不同植被系统、基质为河砂的潜流型人工湿地净化生活污水总氮和总磷的效果,并同无植被系统、相同基质的潜流型人工湿地净化效果进行了比较,结果表明:在较低浓度范围里无植被的人工湿地和3种有植被的人工湿地对污水中总氮有较好的去除作用,随着污水中总氮浓度的增加,虽然无植被的人工湿地和有植被的人工湿地去除总氮的效果均有下降的趋势,但有植被的人工湿地仍然能维持较高的总氮去除水平,无植被的人工湿地总氮去除效果则下降较快。在有植被的人工湿地中,以石菖蒲植被人工湿地氮素净化能力最强,其次为灯心草和蝴蝶花,这与植被自身吸收同化污水中氮素水平以及植物根系微生物作用有关。对于污水中总磷的去除,本研究中由于污水中磷素浓度较低,无植被和有植被的人工湿地对污水中磷素均有很好的去除作用,没有明显差异,但不同的植物体中磷素仍有明显的吸收同化富集现象,其中石菖蒲吸收同化磷素能力最强,其次为蝴蝶花和灯心草,植被在人工湿地系统中对于污水中总氮和总磷的去除起着重要的作用。     

Laboratory mesocosm studies of Fe,Al, Mn,Ca, and Mg dynamics in wetlands exposed to synthetic acid coal mine drainage

To evaluate the potential for constructed wetlands to treat acid coal mine drainage, six model wetland mesocosms (each 2.4 m × 15 cm) were filled with Sphagnum peat (15 cm deep), planted either with cattails (Typha latifolia) and living Sphagnum, living Sphagnum only, or left as bare peat (2 mesocosms per treatment). The model wetlands were exposed to synthetic acid coal mine drainage (pH 3.5, concentrations of Fe²⁺, Al³⁺, Mn^2*, Ca²⁺, and Mg²⁺ of 78.8, 10.0, 5.2, 12.0, and 4.5 mg L^?1, respectively) at a rate of 90 mL min^?1, 6 hr d^?1, 5 d wk^?1, over a 16 week period. Chemical analysis of peat at periodic intervals indicated that the model wetlands were net sources of Al³⁺, Mn²⁺ Ca²⁺ and Mg²⁺, but net sinks for Fe²⁺. Type of vegetation had no significant effect on Fe²⁺ retention; of the 204 g of Fe²⁺ added to the model wetland systems, 162 g were retained. Formation of Fe oxides accounted for 73 to 86% of the Fee' retention, with exchangeable Fe contributing 0.2 to 1.2%, organically bound Fe contributing 4 to 19%, and residual Fe contributing 7 to 15% of total Fee' retention. Fe retention was greatest at the inflow ends of the model wetlands where Fe retention appeared to reach saturation at a final Fe concentration in the peat of 235 mg g^?1. At the rate of application of the synthetic acid mine drainage, we estimated that the model wetland systems would have reached complete Fe saturation after 157 days. We suggest that the mesocosm approach could be useful in generating site-specific data that can be applied to the formulation of cost-benefit analyses that can compare a proposed wetland treatment system with alternative conventional chemical methods for treating acid mine drainage.