序批式生物膜/颗粒污泥工艺的同步脱氮除磷效果

针对我国现行污水处理工艺不能在同一个构筑物内实现同步脱氮除磷,特别是能耗高、效率低、占地面积大的现状,将活性污泥和生物膜法相结合,自行设计了一套序批式生物膜/颗粒污泥工艺试验装置,并考察了同步脱氮除磷效果。运行表明,该工艺具有良好的除污效果,当进水COD、NH4+-N、TN、PO34--P的平均浓度分别为302、30.66、32.84、10.45 mg/L时,出水平均浓度分别为25.81、5.91、9.64、2.40 mg/L,平均去除率分别为91.44%、80.69%、70.61%、77.00%;该工艺具有良好的反硝化除磷效果,每消耗1 mg的NO3--N可以去除1.04 mg的PO34--P。     

浅析水中砷的去除

介绍了含砷废水对人类的危害,阐述了八种含砷废水的处理方法,并对各种除砷技术的优缺点及发展情况进行了分析,提出生物除砷法必将成为最有发展前景的处理方法。     

潜流碎石床湿地去除二级处理出水中的磷

传统的污水处理厂以去除BOD5、SS为目标,除磷能力较差。为此,开展了潜流碎石床湿地去除二级生化处理出水中磷的研究。结果表明,当进水TP为1.80 mg/L时出水为0.27mg/L,去除率为85%。与此同时,对BOD5、COD、SS、NH3-N等也有一定程度的去除,出水水质基本满足《生活杂用水水质标准》(CJ/T 48—1999)。     

生物膜法去除水中微量有机物的动力学研究

采用生物膜反应器，对水中４种代表性的微量有机物：苯酚、苯、甲苯、二甲苯进行了辅助代谢研究，建立了一级反应数学模型；通过实验确定了相应的一级反应动力学常数；并讨论了辅助代谢过程的主要影响因素     

不同活性炭对水中天然有机物去除效果的研究

通过吸附实验,对比研究压块破碎炭和活性无烟煤对水中天然有机物的去除效果,探索出科学合理的选炭方法。实验结果表明:活性无烟煤对UV_(254)和TOC的去除效果均优于压块破碎炭;且活性无烟煤对三卤甲烷、三氯乙醛、三卤甲烷生成势的控制效果也均优于压块破碎炭。     

生物膜电极工艺去除微污染源水中氨氮的研究

采用生物膜电极工艺去除微污染源水中的氨氮.在好氧区利用金属阳极电解产氧,在硝化细菌的作用下使氨氮转化为硝酸盐氮或亚硝酸盐氮;在缺氧区利用碳棒作为阴极电解产氢,实现反硝化脱氮.试验结果表明:C/N、电流强度、氨氮浓度、进水流量等对去除总氮均有影响;在流量为3 L/d、无外界供氧、电流强度为19.5 mA、C/N为1的条件下,当进水COD为10 mg/L、氨氮为7 mg/L时,对总氮的去除率可达95.6%,显著改善了水质.     

甲醇为碳源时生物滤池去除二级出水中氮、磷的研究

以甲醇为碳源,进行了生物滤池去除二级处理出水中氮、磷的试验研究。结果表明,随着甲醇投量的增大则生物滤池出水中的总氮浓度降低,但对总磷的去除率呈下降趋势。当甲醇投量为10mg／L时,生物滤池出水中的总氮〈6．60mg／L,对总氮的去除率〉37％,对总磷的去除率〉43％;当甲醇投量为20mg／L时,生物滤池出水中的总氮〈1．20mg／L,对总氮的去除率〉88％,对总磷的去除率〉9％;当甲醇投量为30mg／L时,生物滤池出水中的总氮〈1．20mg／L,对总氮的去除率〉88％,对总磷的去除率〉6％。当滤速在3～8．5m／h间变化时,陶粒滤池的脱氮除磷效果基本不受影响;砂滤池的脱氮除磷效果稍优于陶粒滤池。     

陶瓷膜对水中重金属去除的研究

为了应对给水厂可能存在的金属污染风险,该文研究了陶瓷膜对水中金属铅、铬(六价)、铊和镍污染物的去除效果。试验发现:200nm和50nm陶瓷膜能有效去除重金属Pb污染物,平均去除率大于90%;对Cr6+、Tl的去除效果差,对Ni的有部分去除效果;单独配Pb溶液陶瓷膜过滤对Pb的去除效果优于混合配制几种重金属溶液再陶瓷膜过滤。     

水中类固醇类环境激素的分布及去除

针对水中的类固醇类环境激素对生物和人体的内分泌机能造成的不良影响,通过介绍水中类固醇类环境激素的危害、分布及去除,指出水中类固醇类环境激素的风险评价将成为今后的研究方向。     

Nitrogen removal from wastewater by a catalytic oxidation method

The ammonia-containing waste produced in industries is usually characterized by high concentration and high temperature, and is not treatable by biological methods directly. In this study, a hydrophobic Pt/SDB catalyst was first used in a trickle-bed reactor to remove ammonia from wastewater. In the reactor, both stripping and catalytic oxidation occur simultaneously. It was found that higher temperature and higher oxygen partial pressure enhanced the ammonia removal. A reaction pathway, which involves oxidizing ammonia to nitric oxide, which then further reacts with ammonia to produce nitrogen and water, was confirmed. Small amounts of by-products, nitrites and nitrates were also detected in the resultant reaction solution. These compounds came from the absorption of nitrogen oxides. Both the minimum NO2- selectivity and maximum ammonia removal were achieved when the resultant pH of treated water was near 7.5 for a feed of unbuffered ammonia solution.     

Column-mode phosphate removal by a novel highly selective adsorbent

A phosphoric acid resin RGP was immobilized with zirconium(IV) (Zr(IV)) to investigate its applicability in phosphate removal. When loaded with Zr(IV), RGP was changed into an effective ligand exchanger with phosphate sorption capacity of 0.345 mmol/ml. Little metal leakage was observed. Breakthrough of phosphate sorption depended on solution acidity and phosphate concentration. An increase of solution pH greatly suppressed phosphate removal, but even at pH 8.21, about 56% of the added phosphate (2.8mM) in the feed solution could still be sorbed. Electrolytes in the aqueous solution did not interfere with phosphate sorption; on the contrary, an enhancement effect was observed. Due to the high sorption capacity of Zr(IV)-loaded RGP, low concentration of phosphate can be removed at high flow rate (100 h(-1) in space velocity). The sorbed phosphate on the Zr(IV)-loaded RGP could be quantitatively eluted with 0.5M sodium hydroxide solution. The Zr(IV)-loaded RGP is a promising ligand exchanger for treating wastewater containing trace amounts of inorganic phosphate.     

Optimization of phosphate removal in anodizing aluminium wastewater

The wastewater produced after brightening and anodizing aluminium has high concentrations of phosphates and sulphates. The addition of MgO in a first physico-chemical wastewater treatment step makes the selective recovery of phosphates in the form of magnesium phosphates feasible, which may be reused as fertilizer. The proposed wastewater treatment process allows manufacturers to reduce more than 70% of the volume of the precipitate in the sedimentation reactor and more than 50% of the weight of the final disposal sludge. In this study, the use of an alternative low-grade MgO (LG-MgO) as a source of magnesium, which is cheaper than pure MgO, is investigated. The phosphate concentration and pH of the treated wastewater is controlled by the formation and precipitation of newberyite or bobierrite as a function of the magnesium source added. According to experimental data, a reaction mechanism is proposed. Although LG-MgO reacts more slowly than pure MgO and it is necessary to add 3-4 times the stoichiometric amount, this procedure has considerable economic and technical advantages.     

Nitrogen dynamics and removal in a horizontal flow biofilm reactor for wastewater treatment

A horizontal flow biofilm reactor (HFBR) designed for the treatment of synthetic wastewater (SWW) was studied to examine the spatial distribution and dynamics of nitrogen transformation processes. Detailed analyses of bulk water and biomass samples, giving substrate and proportions of ammonia oxidising bacteria (AOB) and nitrite oxidising bacteria (NOB) gradients in the HFBR, were carried out using chemical analyses, sensor rate measurements and molecular techniques. Based on these results, proposals for the design of HFBR systems are presented.The HFBR comprised a stack of 60 polystyrene sheets with 10-mm deep frustums. SWW was intermittently dosed at two points, Sheets 1 and 38, in a 2 to 1 volume ratio respectively. Removals of 85.7% COD, 97.4% 5-day biochemical oxygen demand (BOD₅) and 61.7% TN were recorded during the study.In the nitrification zones of the HFBR, which were separated by a step-feed zone, little variation in nitrification activity was found, despite decreasing in situ ammonia concentrations. The results further indicate significant simultaneous nitrification and denitrification (SND) activity in the nitrifying zones of the HFBR. Sensor measurements showed a linear increase in potential nitrification rates at temperatures between 7 and 16 °C, and similar rates of nitrification were measured at concentrations between 1 and 20 mg NH₄-N/l. These results can be used to optimise HFBR reactor design. The HFBR technology could provide an alternative, low maintenance, economically efficient system for carbon and nitrogen removal for low flow wastewater discharges.     

Nitrogen and phosphorus removal from an abattoir wastewater in a SBR with aerobic granular sludge

The formation and performance of granular sludge was studied in an 8 l sequencing batch reactor (SBR) treating an abattoir (slaughterhouse) wastewater. Influent concentrations averaged 1520 mg l⁻¹ volatile suspended solids (VSS), 7685 mg l⁻¹ Chemical oxygen demand (COD), 1057 mg l⁻¹ total kjeldahl nitrogen (TKN), 217 mg l⁻¹ total P. The COD loading was 2.6 kg m⁻³ d⁻¹. The SBR was seeded with flocculating sludge from a SBR with an 1 h settle time, but granules developed within 4 days by reducing the settle time to 2 min. The SBR cycle also had 120 min mixed (anaerobic) fill, 220 min aerated react, and 18 min draw/idle. The granules had a mean diameter of 1.7 mm, a specific gravity of 1.035, a density of 62 g VSS l⁻¹, a zone settling velocity (ZSV) of 51 m h⁻¹, and a sludge volume index (SVI) of 22 ml g⁻¹. Without optimizing process conditions, removal of COD and P were over 98%, and removal of N and VSS were over 97%. Nitrification and denitrification occurred simultaneously during react. The results indicate that conventional SBRs treating wastewaters with flocculating sludge can be converted to granular SBRs by reducing the settle time.     

Hybrid anion exchanger for trace phosphate removal from water and wastewater

Throughout recent decades, the wastewater treatment industry has identified the discharge of nutrients, including phosphates and nitrates, into waterways as a risk to natural environments due to the serious effects of eutrophication. For this reason, new tertiary treatment processes have abounded; these processes generally utilize physico-chemical and biological methods to remove nutrients from secondary wastewaters. The disadvantages of such methods involve larger reactor volumes, operating costs, and waste sludge production; furthermore, complete nutrient removal is unattainable due to thermodynamic and kinetic limitations. The subject study presents the development and performance of a new phosphate-selective sorbent, referred to as hybrid anion exchanger or HAIX. HAIX combines durability and mechanical strength of polymeric anion exchange resins with high sorption affinity of hydrated ferric oxide (HFO) toward phosphate. HAIX is essentially a polymeric anion exchanger within which HFO nanoparticles have been dispersed irreversibly. Laboratory studies show that HAIX selectively removes phosphate from the background of much higher concentrations of competing sulfate, chloride and bicarbonate anions due to the combined presence of Coulombic and Lewis acid-base interactions. Experimental results demonstrate that HAIX's phosphate-sulfate separation factor is over two orders of magnitude greater than that of currently available commercial ion exchange resins. Additionally, optimal HAIX performance occurs at typical secondary wastewater pH conditions i.e., around 7.5. HAIX is amenable to efficient regeneration and reuse with no noticeable loss in capacity.     

Nitrogen and phosphorus removal from municipal wastewater effluent using microalgal biofilms

Microalgal biofilms have so far received little attention as post-treatment for municipal wastewater treatment plants, with the result that the removal capacity of microalgal biofilms in post-treatment systems is unknown. This study investigates the capacity of microalgal biofilms as a post-treatment step for the effluent of municipal wastewater treatment plants. Microalgal biofilms were grown in flow cells with different nutrient loads under continuous lighting of 230 μmol/m²/s (PAR photons, 400-700 nm). It was found that the maximum uptake capacity of the microalgal biofilm was reached at loading rates of 1.0 g/m²/day nitrogen and 0.13 g/m²/day phosphorus. These maximum uptake capacities were the highest loads at which the target effluent values of 2.2 mg/L nitrogen and 0.15 mg/L phosphorus were still achieved. Microalgal biomass analysis revealed an increasing nitrogen and phosphorus content with increasing loading rates until the maximum uptake capacities. The internal nitrogen to phosphorus ratio decreased from 23:1 to 11:1 when increasing the loading rate. This combination of findings demonstrates that microalgal biofilms can be used for removing both nitrogen and phosphorus from municipal wastewater effluent.     

Retention and removal of pathogenic bacteria in wastewater percolating through porous media: a review

Properly designed biological filters or infiltration systems have the capacity to significantly reduce effluent concentrations of pathogenic microorganisms in wastewater. The retention and elimination of microbial cells in biological wastewater filter systems is influenced by several factors. In this review, these factors are discussed. Immobilization of microbial cells moving through a porous media is influenced by mechanisms such as physical straining as well as adsorption to porous media. The grain size of porous media and bacterial cell size are important factors affecting the straining of bacteria, as are the hydraulic loading rate or the extent of clogging layer development in the filter. Adsorption of cells to the porous media is influenced by the content of organic matter, degree of biofilm development, and electrostatic attraction due to ion strength of the solution or electrostatic charges of cell- and particle surfaces. The rate of inactivation of pathogenic microorganisms, in adsorbed or liquid phases, has been shown to be affected by abiotic and biotic factors such as moisture content, pH, temperature, organic matter, bacterial species, predation, and antagonistic symbiosis between microorganisms in the system.     

Ammonium removal using a novel unsaturated flow biological filter with passive aeration

A novel vertical bed process for the removal of ammonium from secondary effluents, using a "passive air pump", has been developed. The process is based on convective aeration caused by a fill and draw operational sequence, and combines the advantages of the vertical wetlands concept with the high loading rates typically associated with trickling filters. Experiments were carried out in a 500-l reactor using simulative effluents and actual municipal secondary effluents. A maximal ammonium removal rate of 1100 g N/m2 reactor/d was achieved using simulative effluents and an effective gravel size of 0.96 mm. At all hydraulic loads applied, the nitrification rate was found to be limited by the oxygen transfer rate. The small-size medium used with simulative effluents clogged when using actual municipal secondary effluents. Two other media (2.46 mm and 4.31 mm) did not clog during the entire experimental period and a maximum removal load of 300 g N/m2 reactor/d was achieved. This value is still much higher than typical rates reported for conventional vertical beds.     

PAFC去除对市政污水中污染物的研究

以PAFC为混凝剂,选择某污水处理厂处理过程的前端、中端和后端为投药点,开展混凝沉淀实验,通过PAFC投加量的改变,分析上清液中污染物变化。结果表明:投加PAFC对SCOD和磷酸盐具有较好的去除能力,对NH3-N和TN的去除无贡献,少量PAFC对p H无影响,电导率有所提高。