Preparation of ultra-lightweight sludge ceramics (ULSC) and application for pharmaceutical advanced wastewater treatment in a biological aerobic filter (BAF)

Novel media-ultra-lightweight sludge ceramics (ULSC) employed in an upflow lab-scale biological aerobic filter (BAF) were investigated for pharmaceutical advanced wastewater treatment. The influences of the volume ratio of pharmaceutical wastewater to domestic wastewater (PW/DW), hydraulic retention time (HRT) and air-liquid ratio (A/L) on chemical oxygen demand (CODCr) and ammonium (NH(4)(+)-N) of the effluent were investigated. When PW/DW of 4:1, HRT of 6 h, and A/L of 5:1 were applied, the mean effluent concentration of NH(4)(+)-N was 6.2 mg L(-1), and the maximum CODCr concentration in the effluent was 96 mg L(-1). Both NH(4)(+)-N and CODCr did not exceed the limits of the national discharge standards (NH(4)(+)-N ≤ 15 mg L(-1), CODCr ≤ 100 mg L(-1)). In addition, the BAF system showed a strong capacity of further removal from NH(4)(+)-N of the effluent.     

The performance of biological anaerobic filters packed with sludge-fly ash ceramic particles (SFCP) and commercial ceramic particles (CCP) during the restart period: Effect of the C/N ratios and filter media

Two lab-scale upflow biological anaerobic filters (BAF) packed with sludge-fly ash ceramic particles (SFCP) and commercial ceramic particles (CCP) were employed to investigate effects of the C/N ratios and filter media on the BAF performance during the restart period. The results indicated that BAF could be restarted normally after one-month cease. The C/N ratio of 4.0 was the thresholds of nitrate removal and nitrite accumulation. TN removal and phosphate uptake reached the maximum value at the same C/N ratio of 5.5. Ammonia formation was also found and excreted a negative influence on TN removal, especially when higher C/N ratios were applied. Nutrients were mainly degraded within the height of 25 cm from the bottom. In addition, SFCP, as novel filter media manufactured by wastes–dewatered sludge and fly ash, represented a better potential in inhibiting nitrite accumulation, TN removal and phosphate uptake due to their special characteristics in comparison with CCP.     

Simultaneous ammonium-nitrogen and copper removal, and copper recovery using nitrifying biofilm from the ultra-compact biofilm reactor

Simultaneous ammonium-nitrogen (NH(4)(+)-N) and copper removal, and copper recovery in synthetic wastewater using nitrifying biofilm from an ultra-compact biofilm reactor (UCBR) was demonstrated in batch studies, which consisted of three phases: Phase 1 for NH(4)(+)-N and copper removals, Phase 2 for copper recovery, and Phase 3 for NH(4)(+)-N removal. The results showed that more than 96.3% of copper was removed within 60min, while 60.1% of the adsorbed copper was recovered through rinsing the biofilms with 0.1mM of ethylenediaminetetraacetic acid (EDTA). The nitrifying biofilm was able to adsorb 0.245mg of copper/g of biofilms. After recovery treatment, 29.4% of copper remained bound within the nitrifying biofilms. No significant inhibitory effects towards NH(4)(+)-N removal in the presence of 0.92mg copper/L was noted in Phase 1 compared with the control test. However, lower initial pH condition in the recovery process and the accumulation of copper on the biofilm led to 50% inhibition on NH(4)(+)-N removal efficiency in the subsequent phase.     

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     

Effect of grain-slag media for the treatment of wastewater in a biological aerated filter

Grain-slag was applied as the media of biological aerated filters (BAF). The performance of two lab-scale BAF was monitored for 6 months to compare the effect of grain-slag with haydite as media. Under ammonia nitrogen load rates varying from 0.49 to 1.21 kg NH(3)-N(m(3)d)(-1), the overall NH(3)-N reductions of the BAF supported by grain-slag and haydite averaged 84.30% and 80.87%, respectively. Higher ammonia nitrogen removal in the BAF with grain-slag was attributable to its buffering pH value capacity by stripping calcium carbonate (CaCO(3)). In terms of removing organic matter, turbidity and colourity, the efficiency of the BAF with grain-slag was lower than that with haydite, but more than 78%, 79% and 80% of fed organic matter, turbidity and colourity was still removed, respectively. So it is feasible for grain-slag to be applied as the media of BAF. The results obtained from the research of ammonia nitrogen removal rate versus pH values indicate that ammonia nitrogen removal rates were not distinctly dependent of pH values in the BAF supported by grain-slag. More than 85% of ammonia nitrogen was removed at pH values from 5.2 to 7.8 ranges. Grain-slag can strip CaCO(3) into the wastewater to buffer pH value and maintain optimal nitrification rates.     

Effect of ammonium concentration on the emission of N(2)O under oxygen-limited autotrophic wastewater nitrification

A significant amount of nitrous oxide (N(2)O), which is one of the serious greenhouse gases, is emitted from nitrification and denitrification of wastewater. Batch wastewater nitrifications with enriched nitrifiers were carried out under oxygen-limited condition with synthetic (without organic carbon) and real wastewater (with organic carbon) in order to find out the effect of ammonium concentration on N(2)O emission. Cumulated N(2)O-N emission reached 3.0, 5.7, 6.2, and 13.5 mg from 0.4 l of the synthetic wastewater with 50, 100, 200, and 500 mg/l NH(4)(+)-N, respectively, and 1.0 mg from the real wastewater with 125 mg/l NH(4)(+)-N. The results indicate that N(2)O emission increased with ammonium concentration and the load. The ammonium removal rate and nitrite concentration also increased N(2)O emission. Comparative analysis of N(2)O emission from synthetic and real wastewaters revealed that wastewater nitrification under oxygen-limited condition emitted more N(2)O than that of heterotrophic denitrification. Summarizing the results, it can be concluded that denitrification by autotrophic nitrifiers contributes significantly to the N(2)O emission from wastewater nitrification.     

Treatment of tomato processing wastewater by an upflow anaerobic sludge blanket-anoxic-aerobic system

The main objective of this study is to assess the achievability of stringent discharge criteria i.e. BOD(5)<15 mg/L, TSS<15 mg/L and NH(4)-N<1mg/L during the treatment of tomato processing wastewater with COD of 2800-15,500 mg/L, BOD(5) of 1750-7950 mg/L, TKN of 48-340 mg/L and NH(4)-N of 21-235 mg/L. Two treatment systems, a UASB-aerobic system and a UASB-anoxic-aerobic system were tested. Furthermore due to alkalinity deficiency, in the raw wastewater, the study explored varying UASB effluent recirculation flowrates to the UASB influent to reduce additional alkalinity requirements. The UASB-anoxic-aerobic system was effective in treating tomato canning wastewater at an overall HRT of 1.75 days while achieving 98.5% BOD(5), 95.6% COD, 84% TSS and 99.5% NH(4)-N removal producing effluent BOD(5), COD, TSS, NH(4)-N, TKN, NO(2)-N, NO(3)-N and PO(4)-P of 10, 70, 15, 0.5, 3, 0, 60 and 4 mg/L, respectively. The biogas yield was 0.43 m(3)/kg COD removed.     

The integration of methanogenesis with shortcut nitrification and denitrification in a combined UASB with MBR

A combined system consisting of an up-flow anaerobic sludge blanket (UASB) and an aerobic membrane bioreactor (MBR) was operated at 28-30 degrees C and pH 7.8-8.1 for the treatment of low-strength synthetic wastewater enriched with organic carbon and NH4Cl. The MBR slurry was recirculated into the UASB with a ratio of 50-800%. It was found that nitrite was able to accumulate steadily during the nitrification step in the MBR at a low TOC/NH4+-N ratio. The mixed liquid containing NOX(-)-N in the MBR was recirculated to the UASB, and denitrification rather than methanogenesis became the preferred pathway. Whereas, the less carbon requirement for denitrification via nitrite rather than nitrate allowed methanogenesis to proceed simultaneously in the same reactor. The combination of membrane filtration and partial nitrification in the MBR with simultaneous denitrification and methanogenesis in the UASB could stably reach 98% TOC removal and 48.1-82.8% TN removal with recirculation ratio increasing from 50% to 800%.     

Performance of a pilot-scale submerged membrane bioreactor (MBR) in treating bathing wastewater

Bathing wastewater was treated by a pilot-scale submerged membrane bioreactor (MBR) for more than 60 days. The results showed that the removal rates of main pollutants of wastewater such as COD(Cr), LAS, NH(4)(+)-N and total nitrogen (TN) were above 93%, 99%, 99%, and 90%, respectively. The results of denaturing gel gradient electrophoresis (DGGE) and fluorescent in situ hybridization (FISH) indicated that the bacteria were stable. The abundant nitrobacteria intercepted by the membrane led to the high removal rate of ammonia and TN. FISH and 16S rDNA gene sequence analysis revealed that some specific phylogenetic group of bacteria, the Pseudomonas sp. Ochrobactrum anthropi sp. and Enterobacter sp. probably played a major role in the development of the mature biofilms, which led to the severe irreversible membrane biofouling.     

Removal of ammonia as struvite from anaerobic digester effluents and recycling of magnesium and phosphate

A second order kinetic model was developed to predict the rate and extent of NH(4)(+) removal as struvite from anaerobic digester effluents. Alternative to this, NH(4)(+) can be recovered from struvite and the remaining Mg(2+) and PO(4)(3-) can be recycled back to the wastewater to fix more NH(4)(+). The NH(4)(+) solution was retained and the remaining Mg(2+) and PO(4)(3-) were returned back to be mixed with wastewater. In a five-step process, NH(4)(+) recovery was initially 92% and progressively decreased to 77% in the fifth stage, due to loss of Mg(2+) and PO(4)(3-) at each step in the supernatant. Finally, economic analysis of recycling nutrients was performed and compared to the one step process. The cost of NH(4)(+) recovery was calculated as $0.36/kgNH(4)-N which is lower than $7.7/kgNH(4)-N the cost of one step process without considering the market value of struvite obtained in one step process.     

基于好氧反硝化及反硝化聚磷菌强化的低温低碳氮比生活污水生物处理中试研究

【背景】低碳氮比生活污水很难达标处理,多级A/O工艺、生物强化技术及生物膜技术的有机结合可有效解决这一问题。【目的】开发出一种泥膜共生多级A/O工艺并进行中试研究,驯化出高效脱氮除磷菌剂并对系统进行生物强化。【方法】通过测定中试设备出水及污水处理厂出水化学需氧量(Chemical oxygen demand,COD)、氨氮(NH_4~+-N)、硝氮(NO_3~--N)、总氮(Total nitrogen,TN)、总磷(Total phosphorus,TP)对比分析两种工艺的污染物去除效能,利用高通量测序技术对比生物强化技术对系统微生物群落结构的影响。【结果】中试设备对COD、NH_4~+-N、NO_3~--N、TN、TP的去除效果均优于污水处理厂的处理工艺;驯化的低温好氧反硝化菌TN去除率最大值可达84.21%,驯化的低温反硝化聚磷菌群对磷的去除率最高可达85.75%;利用驯化菌群对中试设备进行生物强化后较好地改善了系统NH_4~+-N、NO_3~--N、TN、TP的去除效果;经生物强化后,具有好氧反硝化和反硝化聚磷功能的Pseudomonas菌群明显增多。【结论】泥膜共生多级A/O工艺对于低碳氮比生活污水的处理具有很好的效果,利用生物强化技术可有效提高低温条件下系统污染物去除效能。     

In situ simultaneous organics and nitrogen removal from recycled landfill leachate using an anaerobic-aerobic process

An anaerobic-aerobic process including a fresh refuse landfill reactor as denitrifying reactor, a well-decomposed refuse reactor as methanogenesis reactor and an aerobic activated sludge reactor as nitrifying reactor was operated by leachate recirculation to remove organic and nitrogen simultaneously. The results indicated that denitrification and methanogenesis were carried out successfully in the fresh refuse and well-decomposed landfill reactors, respectively, while the nitrification of NH(4)(+)-N was performed in the aerobic reactor. The maximum organic removal rate was 1.78 kg COD/m(3)d in the well-decomposed refuse landfill reactor while the NH(4)(+)-N removal rate was 0.18 kg NH(4)(+)-N/m(3)d in the aerobic reactor. The biogas from fresh refuse reactors and well-decomposed refuse landfill reactors were consisted of mainly carbon dioxide and methane, respectively. The volume fraction of N(2) increased with the increase of NO(3)(-)-N concentration and decreased with the drop of NO(3)(-)-N concentration. The denitrifying bacteria mustered mainly in middle layer and the denitrifying bacteria population had a good correlation with NO(3)(-)-N concentration.     

Effect of L-glutamic acid on the growth and ammonium removal from ammonium solution and natural wastewater by Chlorella vulgaris NTM06

The main objective of this laboratory scale experiment was to study the effect of l-glutamic acid on the growth in media and removal of ammonium from ammonium solution and natural wastewater by Chlorella vulgaris NTM06. It was observed that higher levels (1.0% and 1.5%) of l-glutamic acid compared to control (0% l-glutamic acid) negatively affected growth of C. vulgaris NTM06 and enhanced removal of ammonium from ammonium solution as well as natural wastewater. After 24h of incubation, 99% of 169.3mg NH(4)(+)-N/l was removed from ammonium solution by 1.5% l-glutamic acid treated C. vulgairs NTM06 cultures; removal in case of control was 70%. In case of natural wastewaters with initial ammonium concentrations of 1550, 775, 310 and 155 mg NH(4)(+)-N/l, removal after 48 h of incubation were 60%, 88%, 61% and 55% respectively. Ammonium removals from ammonium solutions of pH 4.0-8.0 were similar, whereas adsorption of ammonium ions on to the surface of dead C. vulgaris NTM06 cells was around 11%. Compared to dark, cultures incubated under the light showed higher initial removal of ammonium, however, after 24h, differences were not significant. Further research on the role of l-glutamic acid in micro-algal treatment of wastewater and its combination with other approaches such as co-immobilization of micro-algae with other organisms, starvation of micro-algal cells and the use of polymers is recommended.     

Nitrogen removal from purified swine wastewater using biogas by semi-partitioned reactor

Nitrate and ammonium removal from purified swine wastewater using biogas and air was investigated in continuous reactor operation. A novel type of reactor, a semi-partitioned reactor (SPR), which enables a biological reaction using methane and oxygen in the water phase and discharges these unused gases separately, was operated with a varying gas supply rate. Successful removal of NO(3)(-) and NH(4)(+) was observed when biogas and air of 1L/min was supplied to an SPR of 9L water phase with a NO(2,3)(-)-N and NH(4)(+)-N removal rate of 0.10 g/L/day and 0.060 g/L/day, respectively. The original biogas contained an average of 77.2% methane, and the discharged biogas from the SPR contained an average of 76.9% of unused methane that was useable for energy like heat or electricity production. Methane was contained in the discharged air from the SPR at an average of 2.1%. When gas supply rates were raised to 2L/min and the nitrogen load was increased, NO(3)(-) concentration was decreased, but NO(2)(-) accumulated in the reactor and the NO(2,3)(-)-N and NH(4)(+)-N removal activity declined. To recover the activity, lowering of the nitrogen load and the gas supply rate was needed. This study shows that the SPR enables nitrogen removal from purified swine wastewater using biogas under limited gas supply condition.     

石灰石滤柱出水回流曝气生物滤池系统的处理效能及微生物群落多样性

[背景]曝气生物滤池(Biological Aerated Filter,BAF)对有机物和氨氮的处理效果较好,但除磷效果不佳.[目的]提高BAF系统的除磷效能.[方法]在缺氧/好氧滤柱后设置了部分采用石灰石滤料的滤柱(未添加石灰石滤料的系统作为对照组),对比分析了使用石灰石滤柱出水回流BAF系统的处理效能,通过最大或...     

黑臭水体生物修复中各粒级浮游植物与环境因子的关系

通过对黑臭水体生物修复过程中水体理化指标以及浮游植物粒经分级叶绿素a的分析,探讨了水体生物修复对理化因子的影响以及与各粒级浮游植物与理化因子的关系。生物修复实施后,各试验组CODCr和BOD5均呈下降趋势,试验组C、D、E的氨氮、总氮和总磷净化效果均较显著,氨氮去除率分别达到71.3％、84.0％和93.2％,总氮去除率分别达到45.2％、64.6％和78.0％,总磷下降幅度分别达到46.2％、50.3％和75.5％。其中,试验组理化环境改善最佳的组为E组,其CODCr、NH4和TP指标均较对照组A有明显下降（p <0.05）。Netphytoplankton chla%与CODCr、TN、NH4和TP呈非常显著的负相关（p<0.01）,与NO2-N和NO3-N呈非常显著的正相关;而Nanophytoplankton Chla%和Picophytoplankton Chla%对上述环境因子的响应与Netphytoplankton Chla%相反。     

Ammonia-nitrogen and orthophosphate removal by immobilized Scenedesmus sp. isolated from municipal wastewater for potential use in tertiary treatment

Scendesmus sp. isolated from municipal wastewater, entrapped in calcium alginate as algal sheets was employed to remove inorganic nutrients (N and P) from artificial and real domestic secondary effluents in parallel-plate bioreactor after starvation. The key factors affecting the removal efficiency (NH4+-N and PO4(3-)-P), system stability and reuse efficiency of screens were studied and discussed. It has been shown that cell density in the mixture of algal gel was the key factor compared with the thickness of the gel and the cell density of the reactor. A complete removal of NH4+-N and PO4(3-)-P was achieved within 4h of treatment in parallel bioreactors with the optimal cell density in the mixture of algal (2 x 10(8) algae mL(-1)) and 3mm gel sheets after second cycle. Nine cycles of wastewater treatment in 21 days were accomplished, holding higher removal efficiency. NH(4)(+)-N removal efficiency was 99.1% after 105 min, 100% after 135 min, PO4(3-)-P removal efficiency was 100% after 15 min in domestic secondary effluents. Immobilized Scendesmus sp. is shown to have great potentialities for removal of inorganic nitrogen and phosphorus from treated effluents.     

固定化的栅藻深度脱氮和除磷能力

将栅藻包埋固定在筛网上,经饥饿处理,在平行板式生物反应器中对人工污水进行深度净化后,测定藻细胞生长期和饥饿时间对NH4^＋-N和PO4^3-P去除效率影响以及净化前后藻细胞生理变化的结果表明,生长静止初期藻细胞的氮和磷去除率高于对数期的,细胞饥饿48h的氮和磷去除率大于饥饿24和12h,第2个循环中处理4h的氨氮和磷的去除率可分别达到90％和70％以上。     

para-Chlorophenol inhibition on COD, nitrogen and phosphate removal from synthetic wastewater in a sequencing batch reactor

COD, nitrogen, phosphate and para-chlorophenol (4-chlorophenol, 4-CP) removal from synthetic wastewater was investigated using a four-step sequencing batch reactor (SBR) at different sludge ages and initial para-chlorophenol (4-CP) concentrations. The nutrient removal process consisted of anaerobic, oxic, anoxic and oxic phases with hydraulic residence times (HRT) of 1/3/1/1 h and a settling phase of 0.75 h. A Box-Wilson statistical experiment design was used considering the sludge age (5-25 days) and 4-CP concentration (0-400 mg l(-1)) as independent variables. Variations of percent COD, NH4-N, PO4-P and 4-CP removals with sludge age and initial 4-CP concentration were investigated. Percent nutrient removals increased with increasing sludge age and decreasing 4-CP concentrations. Low nutrient removals were obtained at high initial 4-CP concentrations especially at low sludge ages. However, high sludge ages partially overcome the adverse effects of 4-CP and resulted in high nutrient removals. COD, NH4-N, PO4-P and 4-CP removals were 76%, 72%, 26% and 34% at a sludge age of 25 days and initial 4-CP concentration of 200 mg l(-1). Sludge volume index (SVI) also decreased with increasing sludge age and decreasing 4-CP concentrations. An SVI value of 104 ml g(-1) was obtained at a sludge age of 25 days and initial 4-CP of 200 mg l(-1).