BAF/O_3预处理工艺后砂滤池的除污效果

以珠江广州段源水为处理对象,考察了曝气生物滤池（BAF）／臭氧（O3）预处理工艺后砂滤池的除污效果。结果表明,砂滤池出水CODMn、NH4^＋ -N和浊度的平均值分别为2．19、0．099mg／L和0．225NTU,NO2^- -N的最高值为0．003mg／L;相对于沉淀池出水,砂滤池对上述指标的平均去除率分别为27．60％、66．88％、69．88％和98．53％。BAF和臭氧塔提高了源水的DO浓度,其对浊度和有机物的去除作用降低了砂滤池的反冲洗频率,从而有利于提高生物膜中微生物的数量和活性;臭氧氧化可提高源水的可生化性,且水中没有残留臭氧,也为砂滤池的生物降解作用提供了有利条件。     

Nitrate removal from water using zero‐valent aluminium

Nitrate pollution in surface and groundwater is known to adversely affect human health, water quality and the health of aquatic ecosystems. Zero‐valent aluminium is a strong reductant for ions such as nitrate. In this study, its use in nitrate reduction efficiency was evaluated as a function of pH, aluminium dosage and aluminium particle size through a lab‐scale investigation. The most effective pH for complete nitrate removal, with an initial concentration of 14.0 ± 1.0 mg N/L, was found to be 13 ± 0.2. Under this condition, complete removal was achieved in 5 min, using aluminium particle size of 1–3 µm and aluminium‐to‐nitrate (NO₃^–‐N) ratio of 125. The 1–3 µm and 297–841 µm aluminium particles removed nitrate at a reaction rate constant (k) of 0.048 ± 0.017 (mg‐N/L)^1.53/min and at 0.042 ± 0.014 (mg‐N/L)^1.28/min, respectively. The use of smaller aluminium particles was found to be more effective for nitrate removal than large particles, and it was observed that for these particle sizes, aluminium dosages was less of a factor than any other experimental conditions evaluated.     

Comparison of polyaluminum silicate chloride and electrocoagulation process,in natural organic matter removal from surface water in Ghochan,Iran

Removal of natural organic matter (NOM) is one of the most important objectives of water treatment plants but reducing these pollutants either present in water as dissolved or suspended form is not as efficient as is required in conventional treatment plants. The purpose of this study was comparison performance of composite polyaluminum silicate chloride (PASiC) and electrocoagulation (EC) process by aluminum electrodes in NOM removal from raw surface water. In this study, the effects of turbidity, total organic compounds (carbons) (TOC), adsorption at a wavelength of 254 nm (UV254), chemical oxygen demand (COD), alkalinity, residual aluminum in finished water by application of EC process and PASiC were investigated. The results demonstrate that PASiC coagulant at optimum concentration of 1–5 ml/L was capable of removing TOC, COD, U.V., and turbidity from raw water by 93.77, 93.5, 63 and 95 %, respectively. In contrast, EC process, removed TOC, COD, UV and turbidity from raw water by 89, 99.75, 37 and 50%, respectively. The pilot-scale results demonstrated the significant advantage of PASiC compared to EC process in removal of NOM and turbidity form raw water. Residual aluminum in finished water was below the recommended WHO guidelines 0.2 mg/L for both processes. Finally it can be concluded that PASiC and EC process are reliable, efficient and cost-effective methods for removal of NOM from surface water.     

新生态水合氧化铁去除水中磷酸根的效能研究

以新生态水合氧化铁(FHIO,由高铁酸钾和氯化亚铁配制)为混凝剂,考察了对水中磷酸根的处理效能,以及有机物浓度、pH、温度、浊度等参数对其去除磷酸根的影响。通过对原水pH和浊度变化的分析,发现FHIO的水解过程不同于普通铁盐,可形成细小、比表面积大、吸附能力强的铁氧体。在投加氯化铁进行混凝时,随着投量(6、7、8mg/L)的增加,对磷酸根的去除率分别达到了54%、59%、70%。而在相同的总铁投量下,FHIO对磷酸根的去除率分别提高了11%、13%、9%。水中有机物浓度的增加,对FHIO的除磷效果有一定的影响,这是因为有机物在一定程度上抑制了Fe(Ⅱ)的氧化,间接地影响了FHIO的生成,从而降低了除磷效果。在较低温度、pH和浊度时,FHIO对磷酸根的去除效果明显优于单独铁盐的,这是由于FHIO的无定形状态和细小的颗粒度决定其受这些因素的影响较小。     

PAC和PAM复合混凝剂处理垃圾渗滤液的研究

通过投加混凝剂聚合氯化铝(PAC)和助凝剂聚丙烯酰胺(PAM)对垃圾渗滤液进行混凝沉淀处理,根据单因素和正交试验确定其最佳工艺条件.结果表明,混凝的最佳条件:PAC投加量为750 mg/L、PAM投加量为15 mg/L、快速(150 r/min)搅拌1 min、中速(45 r/min)搅拌6min、慢速(35 r/min)搅拌7 min、在快速混合之后投加助凝剂.在该处理条件下,系统对垃圾渗滤液中COD和浊度的去除率达到最大,分别为27.45%和65.80%.     

管道混凝/超滤工艺深度处理回用水的中试研究

采用管道混凝/超滤组合工艺深度处理回用水,考察了其处理效能及影响因素.结果表明,在相同条件下FeCl_3的混凝效果优于PAC的;组合工艺对COD_(Mn)和UV_(254)的去除率均随混凝剂FeCl_3的投量及混凝时间的增加而增大;组合工艺深度处理回用水的最佳工况:膜通量为64L/(m~2·h)、混凝剂FeCl3投量为7 mg/L、混凝时间为100 S,此时对浊度、COD_(Mn)和UV_(254)的去除率分别可达84.1%、28.6%和52.4%.     

Removal of leachate pollutants using flocculation method at simultaneous factors of optimum pH and Tacca leontopetaloides biopolymer flocculant (TBPF) dosage via face-centred central composite design

The effect of the interaction factor between pH and dosage is important in leachate wastewater treatment. This study aims to remove leachate pollutants such as turbidity, total suspended solid (TSS), chemical oxygen demand (COD) and colour using simultaneous factors of plant-based Tacca leontopetaloides biopolymer flocculant (TBPF) dosage and leachate pH. The flocculation process was carried out through jar test by applying the perikinetic theory and statical analysis (face-centred central composite design). The results found that the optimum leachate pH and TBPF dosage were pH 3 and 150 mg/L, respectively. The highest removal of leachate pollutants reached up to 69% with a second-order perikinetic model; R² = 0.9545 and k = 9 × 10⁻⁶ L/mg/min were obtained. Simultaneous interaction factors between leachate pH and TBPF dosage on turbidity and TSS removal were found significant and hence can be applied in the actual leachate wastewater treatment industry, particularly at the primary stage using the proposed model.     

Particle characterization in retail environments: concentrations,sources, and removal mechanisms

Particles in retail environments can have consequences for the occupational exposures of retail workers and customers, as well as the energy costs associated with ventilation and filtration. Little is known about particle characteristics in retail environments. We measured indoor and outdoor mass concentrations of PM₁₀ and PM_2.5, number concentrations of submicron particles (0.02–1 μm), size‐resolved 0.3–10 μm particles, as well as ventilation rates in 14 retail stores during 24 site visits in Pennsylvania and Texas. Overall, the results were generally suggestive of relatively clean environments when compared to investigations of other building types and ambient/occupational regulatory limits. PM₁₀ and PM_2.5 concentrations (mean ± s.d.) were 20 ± 14 and 11 ± 10 μg/m³, respectively, with indoor‐to‐outdoor ratios of 1.0 ± 0.7 and 0.88 ± 1.0. Mean submicron particle concentrations were 7220 ± 7500 particles/cm³ with an indoor‐to‐outdoor ratio of 1.18 ± 1.30. The median contribution to PM₁₀ and PM_2.5 concentrations from indoor sources (vs. outdoors) was 83% and 53%, respectively. There were no significant correlations between measured ventilation rates and particle concentrations of any size. When examining options to lower PM_2.5 concentrations below regulatory limits, the required changes to ventilation and filtration efficiency were site specific and depended on the indoor and outdoor concentration, emission rate, and infiltration level.     

超细粉体凹凸棒石助凝去除富营养化河水中的藻类

考察了投加超细粉体(200目)凹凸棒石对聚合氯化铝(PAC)混凝沉淀去除富营养化河水中藻类的影响.结果表明,添加凹凸棒石能大大提高PAC对浊度和叶绿素a的去除效果.且可以明显增加絮体的密度,改善絮体的沉降性能,抑制絮体中藻类的上浮.当PAC投量为40ms/L、凹凸棒石投量为0.08%时,PAC与凹凸棒石联用对浊度和叶绿素a的去除率较单用PAC时分别提高了14.5%和14.0%,形成的絮体沉降体积仅为单用PAC时的1/2,降低了后续处理难度.     

Sludge settling and algal flocculating activity of extracellular polymeric substance (EPS) derived from bacillus cereus SK

Exopolysaccharides (EPS) of microbial origin is a promising alternative to chemical flocculants due to their sustainability and eco‐friendly nature. In the present study, EPS produced by Bacillus cereus SK was studied and their flocculating activity was investigated. On incubation for 48 h, B. cereus SK produced 0.919 ± 0.022 g/L of EPS from a cell mass of 3.59 ± 0.06 g/L. The isolated EPS was identified as glycoprotein and chemical characterization by FTIR spectroscopic analysis suggested the presence of hydroxyl, amino and carboxyl groups. The kaolin clay flocculating activity of 83.4% was obtained on treatment with 12 mg/L of EPS. At 30% (v/v) of EPS 31.22 ± 4.71 mL/g of Sludge volume index (SVI) and 34.44 ± 1.51 mL/g of algal flocculation was observed. The EPS produced by B. cereus SK was non‐toxic and did not exert any adverse effect on Danio rerio even at a concentration of 800 mg/mL.     

臭氧系统在净水厂深度处理中的应用

介绍了某水厂臭氧生物活性炭（O3／BAC）深度处理工艺中臭氧系统的组成、工作条件、设备技术参数。生产运行结果表明，采用预O3可节省矾耗20％，O3／BAC深度处理技术对浊度、色度、CODMn、NH4^＋-N、NO2^--N的去除效果好，出水平均浊度为0．121～0．161NTU，去除率〉99．25％；出水CODMn值为0．48～1．57mg／L，去除率为57％～77％；出水NH4^＋-N平均值为0．02～0．237mg／L，去除率为61％～99．7％；出水NO2^--N值为0．001～0．053mg／L，去除率最高达99．74％．     

混凝沉淀/PAC吸附/超滤工艺处理引黄水库冬季原水

采用混凝沉淀/粉末活性炭吸附/超滤工艺(简称PAC-UF工艺)处理黄河下游引黄水库冬季原水,中试结果表明:当处理冬季低温低浊水时,聚合氯化铝的最佳投量为6 mg/L,粉末活性炭的最佳投量为20 mg/L;PAC-UF工艺可以将出水的浊度控制在0.1 NTU以下,去除率达98%以上;投加20 mg/L的粉末活性炭能使混凝沉淀/UF工艺对COD_(Mn)和UV_(254)的平均去除率分别提高12%和15%;同时,投加粉末活性炭还能够缓解超滤膜的不可逆污染,但缓解的程度有限.     

Coagulation of turbid water and softening of hardwater with Moringa oleifera seeds

In this study, the effects of 5 process variables on softening hardwater and coagulation of surface water with a M. oleifera seed extract were investigated. Multiple regression analysis showed a strong correlation (R² (adj.) = 0.99 between M. oleifera seed dosage and the initial hardness of synthetic hardwater. Since M. oleifera is known to be a polyelectrolyte, the softening mechanism is likely to be adsorption. An adsorption isotherm developed was approximately linear and conformed to the Langmuir type. For the coagulation studies, the water samples were from three rivers in Kano, Nigeria over a three month period during the rainy season (June‐August 1994). The turbidity of the water sample varied from 105–350 NTU. When used as primary coagulant, M. oleifera was able to achieve up to 99% turbidity removal for two of the water samples at the optimum dosage of 250 mg/l. For the third water sample, the optimum dosage was 450 mg/l which is assumed to be due the high value of the colour of the water. Saving in alum usage of up to 40% was achievable when M. oleifera was used in conjunction with alum.     

臭氧/高锰酸盐预氧化助凝及影响因素

提出了高锰酸盐强化臭氧氧化助凝技术,并分析了复合氧化助凝效果的各种影响因素。试验结果表明,复合氧化比单独臭氧氧化更有利于对浊度的去除。复合氧化的投加顺序是先投加高锰酸盐后投加臭氧,较佳的剂量配比是高锰酸盐0.4mg/L与臭氧1.0mg/L。复合氧化除浊的效果受诸多因素影响,复合氧化可适应更大的G值变化范围;助凝效果受原水水质的影响,原水硬度为160mgCaCO3/L时助凝效果最佳,原水TOC浓度为3mg/L时对混凝的影响最小;低温有助于复合氧化助凝;复合氧化受pH值影响较小,可以适应较大范围的pH值变化。与臭氧氧化相比,复合氧化更能适应水力和水质条件的变化。     

混凝法去除水体中邻苯二甲酸二甲酯

研究采用强化混凝法去除水体中特征性有机污染物邻苯二甲酸酯类化合物(PAEs).以邻苯二甲酸二甲酯(DMP)为目标物,阳离子混凝剂聚二甲基二烯丙基氯化铵(PDMDAAC)与聚丙烯酰胺(CPAM)为混凝剂,对含DMP的水体进行强化混凝处理,混凝处理后水体中DMP的残余浓度采用高效液相色谱法(HPLC)测定.研究内容还包括混...     

中桥水厂超滤膜深度处理工艺中试研究

分别以滤后水和沉后水作为进水,考察了超滤膜深度处理工艺的净水效能、膜通量、渗透性及清洗方式.结果表明,超滤膜深度处理工艺对浊度、总铁及色度具有较好的去除效果;以滤后水和沉后水作为超滤膜进水时,适宜的膜通量范围分别为(70 ～80)和(50～60) L/(m2·h);超滤膜-粉末活性炭组合工艺对浊度的去除效果很好,当PAC投加量为15 mg/L时,浊度去除率大于80.7％,TOC、CODMn 、UV254及氨氮去除率基本小于30％.     

微砂强化混凝工艺处理微污染水库水研究

根据鹊山水库水低浊、微污染和高藻的水质特点，采用微砂强化混凝工艺对其进行处理，结果表明：微砂强化混凝的效果优于常规混凝，可使沉淀出水水质得到显著提高。当微砂、FeCl3及PAM的投量分别为1000、30、0．5mg／L时，沉淀出水浊度〈0．78NTU，色度〈2倍，对藻类、TOC、CODMn、UV254的去除率分别可达92．6％、85．6％、67．8％和68．8％以上，该方法为处理该水库水的工艺选择提供了泰者。     

Effects of recirculation rate of nitrified liquor and temperature on biological nitrification–denitrification process using a trickling filter

In the modified Ludzack–Ettinger process, high‐energy input is required in a nitrification tank. To address this issue, a new biological nitrification–denitrification system was constructed with a trickling filter for nitrification. The effects of recirculation rate of nitrified liquor and temperature through the treatment of municipal wastewater were evaluated. The highest DN removal efficiency was observed at 6.5 h of hydraulic retention in the denitrification tank and 350% of recirculation rate of nitrified liquid against the influent flow rate. The DN removal efficiencies did not reach theoretical values for all conditions tested because the COD/N ratios in the influent often decreased to less than 5 g‐COD/g‐N and temperatures dropped to less than 15°C in winter. The former inhibited the denitrification process and the latter significantly decreased the bioactivity of nitrifying bacteria. As such, this system is suitable in tropical and subtropical areas with annual minimum temperatures of over 15°C.     

Removal of endosulfan in a sequencing batch reactor: addition of granular activated carbon as improvement strategy

A granular activated carbon‐sequencing batch reactor (GAC‐SBR) was used to assess the removal of organochlorine endosulfan pesticide. The reactor operated in three stages: (I) starter and stabilization; (II) addition of 4 mg/L of endosulfan in feed; and (III) a single addition of 1 g/L of GAC to mixed liquor. During the 249 days of operation, the removal efficiency of COD was 96 ± 2%; for ‐N 72 ± 1%; and for PO₄^?3‐P 48 ± 13%. Was eliminated the 79% of endosulfan in stage II and 99% in stage III, not found its metabolite (endosulfan sulphate) in the reactor effluent. A consortium of eight bacterial strains was identified in the reactor stages, assessing five of them in the presence of 4 mg endosulfan/L by growth kinetics. According to the results, the joint action of the consortium and GAC addition is the responsible of eliminating the pesticide.     

Removal of tetracycline antibiotic by Lemna gibba L. from aqueous solutions

In this study, the efficiency of Lemna gibba L. on tetracycline (TC) removal from the solutions prepared at various initial TC concentrations (50, 100 and 300 µg/L) was investigated. The study was conducted in the reactors planted with Lemna gibba L. plants. Lemna gibba L. plants in the reactors were harvested at various hydraulic retention times. Then, the concentrations of TC were determined by using LC/‐MS‐MS. The maximum removal efficiencies for the TC50, TC100 and TC300 in the planted reactors were 99.8 ± 4.1; 99.9 ± 4.9 and 99 ± 4.9%, respectively. The harvesting times for Lemna gibba L. at TC50, TC100 and TC300 concentrations were determined to be 12, 8 and 12 hours, respectively. First‐, second‐ and pseudo‐first‐order kinetics are determined in the planted reactors (with Lemna gibba L.). According to the study results, second‐order kinetics were obtained at TC50, TC100, TC300 concentrations. As a result, the Lemna gibba L. plant can be used as an alternative treatment method to other advanced treatment methods and it can be done with a cheap method by adapting to existing treatment plants. Lemna gibba L. plants can be used to remove pollutants by applying them to polluted lakes and water bodies.