Bathroom Greywater Characterization and Potential Treatments for Reuse

With the emerging crisis of water, greywaters represent a significant resource of water if considering recycling for uses not requiring a drinking water quality. Samples of greywaters were taken from a few households. Their characterization led to results similar to those in literature. However, they showed a lack of phosphorus in C/N/P ratio. Nevertheless, it was shown that, in our study, median was more appropriate than mean. The potential treatment steps studied during this work were sand bed filtration, adsorption onto granular activated carbon (GAC), and sanitation by chlorine. The sand bed which was supplied with sequential feedings led to a very good removal of total suspended solids (TSS; and consequently of turbidity) as well as to a 30% COD decrease. However, the organic matter withdrawal was more efficient by adsorption onto GAC. The chlorination of greywaters was efficient to decrease the microbial population. Therefore, following the reclaimed water quality which would be required treatment might imply all steps or just one or two. This kind of low-cost device could thus be implemented for reuse such as irrigation, agricultural need, or urban use.     

微灌用均质砂滤料过滤粉煤灰水时对颗粒质量分数与浊度的影响

为了搞清楚微灌用均质砂滤料的过滤效果,作者开展了均质砂滤料过滤对粉煤灰水质的固体颗粒质量分数和水质浊度影响的模型试验。对颗粒质量分数影响试验显示：虽然颗粒质量分数的平均滤除率均在59%以上,但试验数据变化幅度很大,说明过滤对颗粒质量分数的影响较为复杂;滤除率与过滤速度成负相关,与原水颗粒质量分数成正相关;试验数据验证了敏茨过滤方程表述的“过滤是吸附和脱落交互发生的过程”对微灌过滤条件的合理性,证明了微灌过滤水流流态均为非层流,多数情况处在层流与紊流的过渡区内。对浊度影响试验发现：滤层厚度对浊度滤除比起决定性的作用,浊度粒子吸附与脱落时间均大约在5～6 min,滤速对浊度去除率的影响是有限的。比较2个试验可看出：滤后水的颗粒质量分数和浊度值是2个不相关的参数,其过滤过程是截然不同的,进而得出以浊度指标来判断微灌过滤和反冲洗效果是不科学的。该试验为今后微灌过滤技术的发展提供了参考。     

雨水滤清净水系统的设计与试验验证

针对黄土高原发展坡地高效农业面临的缺水及水源水质差而传统微型沉沙池效率低,清淤困难等问题,基于调控降雨径流,高效利用水土资源的理念,根据生物与物理净化的不同特点,设计出一套生态环保型高效滤清净水系统并进行了试验验证。结果表明,能源牧草柳枝稷作为植被过滤带与滤清池组合系统,对泥沙和总磷最大拦截效果分别达到98.62%和93.6%,对化学需氧量(COD)的最大拦截效果达到56%,说明柳枝稷植被过滤带对泥沙和污染物的拦截效果明显。并在此基础上再铺设不同粒径砂石的滤清池,只需拦截植被过滤带下来的柴草,使布置大幅简化,造价大幅降低。该系统可广泛应用于黄土高原坡地高效农业水源净化系统。     

不同补水方式下砂壤土渗滤系统对硝态氮去除效果

在水资源短缺的北京地区利用再生水回补城市河湖,一方面对于水资源的可持续利用有着十分重要的作用,另一方面也可能带来地下水环境的潜在污染风险.该文采用100 cm砂壤土柱模拟(河湖岸底)土地渗滤系统,设置定水头淹水、交替淹水落干、定流速补水和侧向补水4种不同再生水回补方式,研究再生水中硝态氮(NO3-N)在土地渗滤系统中的去除效果和迁移转化规律.结果表明,当水力负荷在0.25~2.65 cm/d范围内时,渗滤系统对NO3-N的去除率随着水力负荷的增大而减小;侧向补水方式下渗滤系统对NO3-N的去除效果最优,平均去除率高达96.1%.在定水头淹水和侧向补水方式下,系统对NO3-N的去除主要发生在土柱的上部,而交替淹水落干和定流速补水条件下,土柱中下部对NO3-N也有一定的去除作用.渗滤系统对NO3-N的去除主要取决于系统内部微生物的分布情况,土层中的反硝化细菌数量越大,该土层对NO3-N的去除率就越高.当水温在15~32℃范围内变化时,定水头淹水和交替淹水落干补水方式下,系统对NO3-N的去除率与温度分别呈指数和幂函数关系.该研究表明土地渗滤系统可实现再生水的进一步净化处理,可为再生水安全回补河湖提供参考.     

Effective Management and Operation of Coagulation and Filtration

The most commonly used water filtration technique involves coagulation and rapid rate filtration, either in conventional plants with flocculation and sedimentation, or in direct filtration plants in which the sedimentation process is omitted. Both versions of coagulation and filtration can be effective for controlling Giardia cysts and Cryptosporidium oocysts, but research done by several investigators has shown that coagulation and filtration must be operated very carefully to attain the best results. When filtered water turbidity is 0.1 ntu or lower, the process is most effective. Careful control of coagulation chemistry and of filtration rate increases, continuous monitoring of filtered water turbidity, and proper management of backwash water are keys to successful filtration.     

Anarwia工艺处理猪场废水节能效果的研究

分析比较了厌氧-加原水-间隙曝气(Anarwia)工艺、SBR(序批式反应器)以及厌氧-SBR工艺处理猪场废水的效果。比较三种工艺处理效果表明：厌氧-SBR工艺处理猪场废水，污染物去除效率低，出水污染物浓度高，不适于猪场废水的处理。Anarwia工艺处理效果与SBR工艺相当，污染物去除率高，出水COD和NH₃-N浓度低。在此基础上，以一个日处理1200 t猪场废水处理工程为例，分析比较了Anarwia与SBR工艺的能耗。就能量消耗有关的工艺参数——污泥量和需氧量而言，Anarwia工艺分别比SBR工艺减少16.4%和95.9%，此外Anarwia工艺每天可产生2784 m³沼气。Anarwia工艺增加了废水提升能耗，但减少了曝气、污泥处理、滗水和搅拌的能耗，结果Anarwia工艺总电耗比SBR工艺低81.0%。Anarwia工艺产生的沼气用于发电能完全补偿消耗的能量，并有剩余。     

孔石莼对养鲍污水的静态净化研究

鱼类代谢产物是养殖水体的主要污染源,但同时也是能被水生植物利用的高能、优质的营养物质（Ｎ和Ｐ）。该文研究了孔石莼对养鲍污水的静态净化过程,分析了孔石莼滤池中水质的变化规律。结果表明,孔石莼能同时吸收水中的三氮和磷酸盐,尤其对氨氮有极强的吸收作用,但对有机物的去除不明显。建立了静态条件下对氨氮的净化模型。用孔石莼净化养殖污水具有净水、节能和收获饵料的综合效果。     

Evaluation of Roughing and Slow Sand Filters for Water Treatment

The present study examined the potential of someroughing filter media, prepared from locally availablematerials in removing organic matter and turbidityfrom surface water. Also, the study included testingthe efficiency of roughing filter followed by slowsand filter in minimizing the suspended load on thesubsequent water treatment steps. Based onmicroorganisms removal and turbidity data, filtermedia consisted of three layers of gravel ranked topamong six of the media tested, showing 84–100%removal for chlorophyll ‘a’ green algae, blue-greenalgae, diatoms, total algal count, bacterial count (at22 and 37 °C), total coliforms, faecal coliform,faecal streptococci, yeast and Candida albicans.Using slow sand filter after roughing filter improvedthe percentage removal of turbidity, where it reachedup to 83% after roughing filter while it reached 92%after slow sand filter. From the view point ofaesthetic quality of the filtered water, the resultsof the analyzed physico-chemical parameters showed nochange before and after the use of the roughing andslow sand filters.     

Potential of Water Hyacinth as a Removal Agent for Heavy Metals from Petroleum Refinery Effluents

Effluents from petroleum refineries contain a diverse range of pollutants including heavy metals. They also contain oil and grease, phenols, sulphides, dissolved solids, suspended solids and BOD-bearing materials. An overview of heavy metal removal from industrial effluents with emphasis on biological methods is given. Results of studies to remove heavy metals in effluents from a petroleum refinery by water hyacinth were presented. Limited success has been demonstrated for the case of iron and zinc, but further work needs to be done. There is a need to strike the right balance between the possible amount of uptake of heavy metal ions and the tendency to suffocate the ecosystem through the depletion and reduction of light and dissolved oxygen. Similarly there is a need for better understanding of the process of enhancement of the capability the water hyacinth to uptake heavy metal ions before the on-set of toxic accumulation.     

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.     

Performance and Kinetic Study on Bioremediation of Diazo Dye (Reactive Black 5) in Wastewater Using Spent GAC–Biofilm Sequencing Batch Reactor

Combinations of sequential anaerobic and aerobic process enhance the treatment of textile wastewater. The aim of this study was to investigate the treatment of diazo dye Reactive Black 5 (RB5)-containing wastewater using granular activated carbon (GAC)–biofilm sequencing batch reactor (SBR) as an integration of aerobic and anaerobic process in a single reactor. The GAC–biofilm SBR system demonstrated higher removal of COD, RB5 and aromatic amines. It was observed that the RB5 removal efficiency improved as the concentration of co-substrate in the influent increased. The alternative aeration introduced into the bioreactor enhanced mineralization of aromatic amines. Degradation of RB5 and co-substrate followed second-order kinetic and the constant (k ₂) values for COD and RB5 decreased from 0.002 to 0.001 and 0.004 to 0.001 l/mg h, respectively, as the RB5 concentration increased from 100 to 200 mg/l in the GAC–biofilm SBR system.     

活性污泥生物除磷机制及其影响因素

高效生物除磷的活性污泥系统主要有Ｐｈｏｒｅｄｏｘ、ＵＣＴ、ＭＵＣＴ、Ａ／Ｏ、间歇式活性污泥法等工艺。其特点是先有一厌氧区，后有一好氧区，厌氧区内发生磷的大量释放、好氧区内则造成磷的大量吸收；主要除磷生物是不动细菌属Ａｃｉｎｅｔｏｂａｃｔｅｒ．ｓｐ，污水性质、毒物、操作参数、溶解氧浓度、厌氧区中投加基质对污泥除磷性能均有一定的影响。     

Using EEFM (Excitation Emission Fluorescence Matrix) to Differentiate the Organic Properties of the Effluents from the Ozonated Biofilters

This study conducted a two-stage experiment. The first stage attempted to establish biostable filter beds. Two parameters, total bacterial count (TBC) and non-purgeable dissolved carbon (NPDOC), measured by passing through a 0.2 μm membrane filter, were selected to compare the difference of biostability of a filtration system with recirculation with different O₃-to-NPDOC ratios of filtered water. The excitation emission fluorescence matrix (EEFM) was used as an effective tool for understanding information regarding organic characteristics by comparing source filtered water before and after ozonation and the effluent during biostablizing filter. During the second stage, a biostable filter was used to compare differences in biodegradability of ozonated products sodium oxalate and sodium acetate. Experimental results demonstrate that both parameters, NPDOC removal and TBC, can be utilized to evaluate the biostabilty of a filter bed. With each parameter, a plateau was reached in roughly 20 days. The source water from Chen Ching Lake (CCL) contained a protein-like substance determined by the EEFM. This protein-like substance was also destroyed by O₃/NPDOC?=?1.1. Soluble microbial products (SMPs) released from the biostablizing filter into the effluent have two peaks in the EEFM, identified as protein-like and humic-like acid. The NPDOC removal for the biostabilizing filter using O₃/NPDOC?=?1.7 was less than that using O₃/NPDOC?=?1.1. Bacterial counts in the effluent from the biostabilizing filter using O₃/NPDOC?=?1.1 was better than that of O₃/NPDOC?=?1.7. This difference can be explained by the high ratio of O₃/NPDOC producing by-products of ozonation that were easily utilized by microorganisms; however, filter bed also released relatively more SMPs owing to increased proliferation of microorganisms attached to glass pellets in the filter. Regarding the differences in decomposition of the by-products of ozonation by the biostable filter, such as sodium oxalate, the NPDOC removal at O₃/NPDOC?=?1.1 was better than that at O₃/DOC?=?1.7. This phenomenon can be explained as previously mentioned.     

Fluoride Removal from Water Using Combined Moringa oleifera/Ultrafiltration Process

The occurrence of fluoride in groundwater has been reported in many countries, mainly because the excess fluoride in drinking water can lead to dental or skeletal fluorosis. Fluoride removal by coagulation with Moringa oleifera seeds, followed by separation with membranes, was investigated in this work. Artificially fluoridated water, at a starting fluoride concentration of 10?mg?L^?1, was submitted to a coagulation process with aqueous extracts of M. oleifera seeds. The coagulation process was followed by ultrafiltration with membranes at different pressures. The coagulation process with 2.5?g?L^?1 of M. oleifera promoted a reduction of 90.90?% in the fluoride content of the treated water, making it possible for poor communities to consume this water. It is noteworthy that the combined coagulation/filtration process using raw coagulant showed the highest values of colour and turbidity, which, however, were still below the limits set for drinking water by Brazilian legislation. The advantage of proposing a sequential process using membrane separation is that it removes colour and turbidity, caused by the use of M. oleifera as a coagulant, resulting in water that meets potability standards.     

Treatment of Road Runoff by a Combined Storm Water Treatment, Detention and Infiltration System

Storm water detention devices collect runoff from impermeable catchments. They provide flow attenuation as well as storage capacity, and rely on natural self-purification processes such as sedimentation, filtration and microbial degradation. The aim was to assess the performance of an experimental combined planted gravel filter, storm water detention and infiltration tank system treating runoff from a car park and its access road. Flows were modeled with the US EPA Storm Water Management Model. An overall water balance of the system was compiled, demonstrating that 50% of the rainfall volume escaped the system as evaporation, whereas, of the remaining 50%, approximately two thirds were infiltrated and one third was discharged into the sewer system. These findings illustrated the importance of evaporation in source control, and showed that infiltration can be applied successfully even on man-made urban soils with low permeability. The assessment of the system’s hydrological efficiency indicated mean lag times of 1.84 and 10.6 h for the gravel filter and the entire system, respectively. Mean flow volume reductions of 70% and mean peak flow reductions of 90% were achieved compared to conventional drainage. The assessment of the pollutant removal efficiency resulted in promising removal efficiencies for biochemical oxygen demand (77%), suspended solids (83%), nitrate-nitrogen (32%) and ortho-phosphate-phosphorus (47%). The most important removal processes were identified as biological degradation (predominantly within the gravel ditch), sedimentation and infiltration.     

Hydraulic Loading Rate Effect on Removal Rates in a BioSand Filter: A Pilot Study of Three Conditions

Safe drinking water is a luxury to approximately 800 million people worldwide. The number of people without access to clean water has been reduced, thanks to technologies like the biosand filter (BSF), an intermittently operated household scale slow sand filter. The BSF outlet (control diameter 0.5??) was modified in this study by reducing the outlet diameter (0.37?? and 0.25??) to determine the effects of hydraulic retention time on removal rates. Filters were dosed with 20?L of spiked lake water daily and observed for pH, dissolved oxygen (DO), fecal coliforms (FC), turbidity, nitrate, nitrite, sulfate, and ammonia until initial flow rates dropped below 0.2?L/min. Consistent with previous studies, the average turbidity was reduced to below 1?NTU; the average DO was reduced by 45?%. No significant difference was observed between the modified BSFs and the control BSF. Removal efficiency of FC was not significantly different between the modified BSFs (93.3?% and 91.9?%) and the control BSF (89.6?%). Mean FC reduction during the startup period (17?days) was significantly greater in the modified 0.25?? BSF when compared with the control during the same time period. After the first 17?days of the experiment, the average reduction efficiency of all filters was >97?%. While source water was below guideline values for nitrate, nitrite, ammonia, and sulfate during the course of the experiment, total nitrogen reduction was observed. The reduction indicates that the plastic BSF is capable of accomplishing limited denitrification during the filtering process.     

基于玉米秸秆滤料的养禽冲洗废水过滤技术

过滤预处理可以有效去除养禽冲洗废水中的悬浮性固体,提高废水处理效率。为了探究玉米秸秆作为滤料的过滤规律,研究了玉米秸秆粒度、压实度和滤料装填高度对养禽冲洗废水过滤预处理的影响,建立了养禽冲洗废水过滤装置的结构模型。通过正交试验和试验验证,结果表明,当玉米秸秆粒度为1cm、压实度为1.4倍密度(74.93 kg/m~3)、滤料装填高度为50cm时滤料有最佳过滤效果,此时过滤后的养禽冲洗废水总固体(TS,TotalSolid)去除率为31.22%,挥发性固体(VS,Volatile Solid)去除率为44.51%,化学需氧量(COD,Chemical Oxygen Demand)去除率为24.07%,NH_4~+-N去除率为21.20%,达到了较好的过滤效果。对比过滤前后养禽冲洗废水厌氧发酵结果,过滤后废水厌氧发酵速率得到了明显提升,缩短了发酵周期,验证了过滤预处理对提高废水处理效率的可行性。试验结果为养殖冲洗废水过滤设备研发提供了理论依据。     

Effect of Equilibrium Solution Ionic Strength on the Adsorption of Zn,Cu, Cd,Pb, As,and P on Aluminum Mining By-Product

Adsorption onto powdered activated carbon (PAC) is a promising option to remove organic micro-pollutants (OMP) from drinking water sources or wastewater. Since this treatment option requires continuous PAC dosing, sufficient contact time and subsequent separation of the PAC, the integration into existing process chains is challenging. In the present investigation, the pre-loading of a deep bed filter with PAC used as fixed bed adsorber was investigated. The retention and distribution of an exemplary PAC in a pumice rapid filter were determined. Gravimetry combined with combustion of the PAC at 550 °C was applied to differentiate between PAC and filter material residues and revealed comparably high PAC immobilization in the upper third of the pumice filter. Comparative adsorption experiments in batch with suspended PAC and continuous filtration tests with immobilized PAC showed advantageous results for immobilized PAC with regard to the removal of OMP and the sum parameters dissolved organic carbon and UV light absorption at 254 nm wavelength. The results indicate that a conventional rapid filter together with PAC can be effectively utilized as fixed bed adsorption filter.     

Nutrient Reduction in Stormwater Pond Discharge Using a Chamber Upflow Filter and Skimmer (CUFS)

Stormwater runoff is a known pollutant source capable of causing surface water degradation, especially in highly populated areas such as Central Florida. Wet detention ponds manage this stormwater, but most of the ponds do not remove enough nutrients, specifically nitrogen and phosphorus, to meet total maximum daily load regulations. This paper presents the use of a chamber upflow filter and skimmer (CUFS) filled with a specific green sorption medium as process modification of stormwater retention ponds, which can increase the removal of nitrogen and phosphorus in the stormwater runoff. Green sorption medium consists of recycled and natural materials that provide a favorable environment for pollutant removal. Water enters the system through the skimmer, which floats on the surface of the detention pond. It travels from the skimmer to the bottom of the chamber where heavier particles settle out before entering the upflow filter. The upflow filter contains 61 cm (24 in.) of green sorption medium providing physicochemical and microbiological processes to remove nitrogen and phosphorus under anoxic/anaerobic conditions. After this treatment, water flows up through the filter and out of the system and eventually travels to Lake Jesup, a eutrophic lake in Central Florida. A total of 28 storm events and seven baseflows were sampled from the site in Seminole County, and ten storm events were sampled from a pilot study of CUFS for statistical analysis and performance evaluation. Significant reductions by the CUFS were confirmed in terms of turbidity, orthophosphorus, total phosphorus, and total suspended solids when the mean values were compared at a 95% confidence level. Reductions also occurred for total nitrogen (TN), but could not be proved by the mean comparison in the field test, whereas the pilot-scale application of the CUFS proved effective for reducing TN at a 95% confidence level. Hydraulic retention time should be increased so as to improve the design for TN removal in future applications.     

Efficiency and Flow Regime of a Highway Stormwater Detention Pond in Washington, USA

Wet detention ponds are a preferable alternative in treating stormwater runoff. Literature suggests that a detention pond’s efficiency in removing principal pollutants of concern, TSS and metals, is highly variable and is affected by a complex array of factors including its geographic location. The objective of this paper was to investigate the TSS and metal removal efficiency of a highway stormwater detention pond in Spokane, Washington along with its flow regime. Pond influent and effluent data for TSS and metal were collected for approximately two years. TSS removal by the pond was found to be 68.1–99.4% with an average of 83.9%. Average metal removal efficiency was 54.7–64.6% which is 72.5–86.9% of the TSS removal. The pond’s flow regime was found to vary with its changing surface topography, a result of sedimentation of suspended solids.