Evaluating the Effects of Aquaculture Wastewater Irrigation with Fertilizer Reduction on Greenhouse Tomato Production,Economic Benefits and Soil Nitrogen Characteristics

The utilization of aquaculture wastewater as irrigation is an effective way to recycle and reuse water and nitrogen fertilizer resources because it contains numerous nutrients.However,it is still unclear that the pattern of substituting aquaculture wastewater irrigation for fertilizer supplementing is conducive to improving the soil nitrogen status,fruit yield and water-fertilizer use efficiency for tomato production.In this context,the experiment was intended to establish the appropriate irrigation regime of aquaculture wastewater in tomato production for freshwater replacement and fertilizer reduction to ensure good yields.Pot experiments were conducted with treatments as farmers accustomed to irrigation and fertilization used as control(CK),1.75 L aquaculture wastewater with base fertilizer(W1),2 L aquaculture wastewater with base fertilizer;and 2.25 L aquaculture wastewater with base fertilizer(W3).We examined the effects of aquaculture wastewater irrigation on soil nitrogen distribution,Nrelated hydrolases,tomato yield,and economic benefits.The results showed that the control treatment had the highest N input,about 24.68%higher than the W3 treatment,while the yield was only about 7.81%higher than W3.This indicated that the overuse of chemical fertilizer was present in the current tomato production.Although the reduction of fertilizer in aquaculture wastewater irrigation caused a decrease in tomato production,this economic loss can be compensated by cost savings in the wastewater disposal.Among aquaculture wastewater treatments,the W3 treatment had the highest overall benefit,achieving 62.63%freshwater savings,37.50%fertilizer input reduction,and an economic return of approximately 19,466 Yuan per hectare higher than the control.Additionally,increasing the irrigation volume of aquaculture wastewater could provide more available nutrients to the soil,which were more prevalent in the form of organic nitrogen.The lower soil nitrate reductase activities(NR)under aquaculture wastewater treatments after harvesting also proved that this pattern was beneficial to reduce soil nitrate nitrogen residues.Overall,the results demonstrate that aquaculture wastewater irrigation alleviates the soil nitrate residues,improves nutrient availability,and results in more economic returns with water and fertilizer conservation for the greenhouse production of tomatoes.

Optimization of double chamber microbial fuel cell for domestic wastewater treatment and electricity production

Microbial fuel cells(M FCs)represent a new approach for treating w aste w ater along w ith electricity production.The present study addressed electricity production from domestic w astew ater using a mediator-less double chamber M FC.The electricity production w as monitored under different operational conditions for both summer and w inter samples.Optimization of the anodic and cathodic chambers resulted in a maximal current of 0.784 and 0.645 m A w ith the maximal pow er intensity of 209 and 117 m W/m2in pow er duration of 24 h for the summer and w inter samples,respectively.Scanning electron microscopy show ed that the bacterial biofilm formation on the anode w as denser for the summer sample than that w hen the w inter sample w as used,so w as the total bacterial count.Therefore,samples taken during summer w ere considered better in electricity production and w aste w ater treatment than those taken during w inter basically because of the high microbial load during the hot season.In parallel,there w as a decrease in both biological oxygen demand(BOD5)and chemical oxygen demand(COD)values which reached 71.8%and 72.85%,respectively at the end of the operation process for the summer sample,w hile there w as no evident decrease for the w inter sample.Optimizing the operating conditions not only increased the potential of using domestic w aste w ater in microbial fuel cells to produce electricity,but also improved the quality of the domestic w aste w ater.

Photocatalytic activity of metal nanoparticle-decorated titanium dioxide for simultaneous H_(2) production and biodiesel wastewater remediation

A set of metal nanoparticle-decorated titanium dioxide(Mx/TiO_(2);where x is the percent by mass,%)photocatalysts was prepared via the sol-immobilization in order to enhance the simultaneous hydrogen(H_(2))production and pollutant reduction from real biodiesel wastewater.Effect of the metal nanoparticle(NP)type(M=Ni,Au,Pt or Pd)and,for Pd,the amount(1%–4%)decorated on the surface of thermal treated commercial TiO_(2)(T_(400))was evaluated.The obtained results demonstrated that both the type and amount of decorated metal NPs did not significantly affect the pollutant reduction,measured in terms of the reduction of chemical oxygen demand(COD),biological oxygen demand(BOD)and oil&grease levels,but they affected the H_(2) production rate from both deionized water and biodiesel wastewater,which can be ranked in the order of Pt_(1)/T_(400)>Pd_(1)/T_(400)>Au_(1)/T_(400)>Ni_(1)/T_(400).This was attributed to the high difference in work function between Pt and the parent T400.However,the difference between Pt1/T400 and Pd1/T400 was not great and so from an economic consideration,Pd/TiO_(2) was selected as appropriate for further evaluation.Among the four different Pdx/TiO_(2) photocatalysts,the Pd3/TiO_(2) demonstrated the highest activity and gave a high rate of H_(2) production(up to 135 mmol·h−1)with a COD,BOD and oil&grease reduction of 30.3%,73.7%and 58.0%,respectively.

Wastewater Remediation Using Algae Grown on a Substrate for Biomass and Biofuel Production

Surging oil, feed and fertilizer costs have impacted farmers particularly hard. Farm-based, local sources of renewable energy could help reduce energy costs for farmers and help develop rural-based processing and manufacturing of biofuel to bolster rural economies. At the same time, nutrient contamination and eutrophication from farming operations have become national problems. Algal-based bioprocessors have the potential to address these problems simultaneously. At Appalachian State University (Appstate) we set out to design, build and test a system that uses algae to capture wastewater nutrients as well as excreted pharmaceuticals, while simultaneously sequestering CO2, producing oil for conversion to biodiesel and feed for livestock. There are a number of problems with current algae growth systems. Algae grown in an open pond or raceway system are suspended in the water in the presence of soluble and suspended waste making most of the current harvest techniques problematic and expensive. Appstate designed algae troughs in which the algae are immobilized on a solid substrate. The laboratory-scale prototype was constructed of three-sided square plastic pipe open at the top. Inside the pipe, there was a series of cloth filters supported by rigid flow-through baffles. Preliminary results observed an average percent reduction of nitrate and phosphorous of 40 and 43, respectively, from different initial nutrient concentrations. Near complete removal (~96%) of estrogen was observed in 2-day trial experiments. In addition, effective increases in algal biomass which can serve as both biofuel feedstock and livestock feed were observed.

Lipid Production by <i>Rhodotorula glutinis</i>from Pulp and Paper Wastewater for Biodiesel Production

This study investigated the potential of oleaginous yeast Rhodotorula glutinis utilizing pulp and paper wastewater effluents as cultivation media for the sustainable production of microbial lipids as biodiesel feedstock. R. glutinis is oleaginous yeast, which has the ability to produce significant quantities of intercellular lipids in the form of triacylglycerols. Yeast lipids are a promising potential feedstock for biodiesel production due to similar fatty acid composition to plant oils. The effect of various carbon sources on biomass production, lipid accumulation, substrate utilization, and fatty acid composition using R. glutinis in the pulp and paper wastewater media was studied. The pulp and paper wastewater was supplemented with glucose, xylose, and glycerol as carbon sources under nitrogen-limited conditions. The maximum lipid productions of 1.3 - 2.9 g&bull;L–1, which corresponded to the intracellular lipid contents of 8% - 15% cell dry weight (CDW), were obtained under various carbon substrates. A kinetic study of the batch fermentation was performed in a 3 L aerobic batch fermenter to describe the cell growth, lipid accumulation, and substrate utilization process, and the kinetic parameter was estimated. The fatty acid profile of oleaginous yeast was rich in palmitic, oleic, and linoleic acids and comparable to vegetable oils. Thus, the results of this study indicated that pulp and paper wastewater could be used to produce lipids as biodiesel feedstock.

A Combined System for Biological Removal of Nitrogen and Carbon from Nylon-6 Production Wastewater

A combined system consisting of hydrolysis acidification, denitrification and nitrification reactors was used to remove carbon and nitrogen from the nylon - 6 production wastewater, which was characterized by good biodegradability and high nitrogen concentration. The influences of Chemical Oxygen Demand （COD） in the influent, recirculation ratio, Hydraulic Residence Time （HRT） and Dissolved Oxygen （DO） concentration on the system performances were investigated. From results it could be seen that good performances have been achieved during the overall experiments periods, and COD, Total Nitrogen （TN）, NH^＋ -N and Suspended Solids （SS） in the effluent were 53, 16, 2 and 24 mg· L^-1, respectively, which has satisfied the first standard of wastewater discharge established by Environmental Protection Agency （EPA） of China. Furthermore, results showed that operation factors, viz. COD in the influent, recirculation ratio, HRT and DO concentration, all had important influences on the system performances.

Potential of <i>Dictyosphaerium</i>sp. LC172264 Concomitant Remediation of Cassava Wastewater and Accumulation of Lipids for Biodiesel Production

As a way of making algal feedstock feasible for biofuel production, simultaneous utilization of microalga Dictyosphaerium sp. LC172264 for cassava wastewater remediation and accumulation of lipids for biodiesel production was investigated. The algal biomass, lipid contents and composition were measured from the autotrophic, heterotrophic and mixotrophic cultured algal cells. Physicochemical parameters of the cassava wastewater and bioremediation potentials were measured. Biodiesel properties were deduced and compared with the standards. The results showed that mixotrophic culture was the best for both biomass accumulation (1.022 g/L) and lipid contents (24.53%). Irrespective of the culture condition, the predominant fatty acids were similar and included 11-Octadecenoic acid (vaccenic acid (C19H36O2), oleic acid (C18H34O2) and 14-methyl pentadecanoic acid (isopalmitic acid (C17H34O2). The percentage reduction of total dissolved solids was 79.32% and 89.78% for heterotrophy and mixotrophy respectively. Biochemical oxygen demand was 72.95% and 89.35%, chemical oxygen demand was 72.19% and 84.03% whereas cyanide contents reduced from the initial value of 450 mg/L to 93.105 (79.31%) and 85.365 mg/L (81.03%) respectively. Dictyosphaerium sp. showed good growth and lipid production under mixotrophic condition and produced good quality biodiesel under the three cultivation modes. Even though both mixotrophic and heterotrophic conditions had good promise of cassava wastewater remediation by Dictyosphaerium sp., mixotrophy showed superiority.

Conceptual Modelling and Data Based Techniques to Understand Urban Water Use and Wastewater Production

A systems approach is used to describe the generation and variation of wastewater in an urban area. This is a multivariable system and its combined response at the outlet of this system, which is usually the entrance ofa wastewater treatment plant, depends on a number of environmental （precipitation and temperature） as well as social （size of the urban area, population changes, water consumption per capita） variables. There is a large number of available models and tools for describing the urban water system, however, the interactions between the individual components are rarely considered within the same modelling framework. In this paper a parsimonious methodology is proposed in order to understand and estimate the wastewater generation and its characteristics in an urban area using any information provided by the available data. The model incorporates both the flows of stormwater discharge and wastewater production that arrive to the wastewater treatment plant. A state dependent variable is introduced to simulate the consumptive uses in the urban area. Data availability and system＇s complexity affect the ability to achieve enhanced model performance, however, in the presented case study, preliminary results from the application of the presented model in the Greater Athens Area illustrate the potential of the conceptual modelling approach.

Effects of operational factors on soluble microbial products in a carrier anaerobic baffled reactor treating dilute wastewater

The effects of feed strength, hydraulic residence time （HRT）, and operational temperatures on soluble microbial product （SMP） production were investigated, to gain insights into the production mechanism. A carrier anaerobic baffled reactor （CABR） treating dilute wastewater was operated under a wide range of operational conditions, namely, feed strengths of 300-600 mg/L, HRTs of 9- 18 h, and temperatures of 10-28℃. Generally, SMP production increased with increasing feed strength and decreasing temperature. At high temperature （28℃）, SMP production increased with decreasing HRT. As the temperature was decreased to 18 and 10℃, the SMP production was at its peak for 12 h HRT. Therefore, temperature could be an important determinant of SMP production along with HRT. A higher SMP to soluble chemical oxygen demand （SCOD） ratio was found at high temperature and long HRT because of complete volatile fatty acid degradation. SMP accounted for 50%-75% of the SCOD in the last chamber of the CABR. As a secondary metabolite, some SMP could be consumed at lower feed strength.

Photothermal-photocatalytic thin-layer flow system for synergistic treatment of wastewater

The integration of the photocatalytic effect into solar steam is highly desirable for addressing freshwater shortages and water pollution.Here,a ternary film structure for the adsorption and photothermal and photocatalytic treatment of wastewater was designed by combining the technique of self-assembled carbon nano paper with a nitrogen composite titanium dioxide(N-TiO_(2))deposited on the surface of carbon nanotubes(CNT)using polyvinylidene fluoride(PVDF)as a substrate.The photogeneration of reactive oxygen species can be promoted by rapid oxygen diffusion at the three-phase interface,whereas the interfacial photothermal effect promotes subsequent free radical reactions for the degradation of rhodamine B(93%).The freshwater evaporation rate is 1.35 kg·m^(-2)·h^(-1)and the solar-to-water evaporation efficiency is 94%.Importantly,the N-TiO_(2)/CNT/PVDF(N-TCP)film not only effectively resists mechanical damage from the environment and maintains structural integrity,but can also be made into a large film for outdoor experiments in a large solar energy conversion device to collect fresh water from polluted water and degrade organic dyes in source water simultaneously,opening the way for applications in energy conversion and storage.

Anaerobic hydrogen production of molasses from mixed microbial communities immobilized by activated granular carbon

Molasses wastewater was evaluated as substrate for biohydrogen production by anaerobic fermentation in a novel continuous mixed attached growth reactor ( CMAGR ) with aeration pretreated sludge attached onto granular activated carbon under continuous flow condition.It was indicated that the CMAGR system was operated at the conditions of influent COD of 2000～6000mg / L , hydraulic retention time ( HRT ) of 6hand temperature of 35 ℃ , when the pH value and oxidation-reduction potential ( ORP ) ranged from 4.16and-434 mV respectively , stable ethanol-type fermentation was formed with the sum of ethanol and acetate concentration ratio of 89.3%to the total liquid products after 40days operation.The H 2 content in biogas and chemical oxygen demand ( COD ) removal were estimated to be 46.6% and 13% , respectively.It was also investigated that the effects of organic loading rates ( OLRs ) on CMAGR hydrogen production system.It was found that hydrogen production yield increased from 3.72 mmol / hL to 12.51 mmol / hL as OLRs increased from 8 kg / m 3 d to 32 kg / m 3 d.The maximum hydrogen production rate of 12.51mmol / hL at a OLR of 32kg / m 3 d and the maximum hydrogen yield by substrate consumed was 130.57 mmol / mol happened at OLR of 16 kg / m 3 d.Greater pHs appeared to be favour to butyrate production and the maximum of 0.51mol / mol was obtained at pH of 4.14.However , ethanol / acetate ratio was greater than 1.1at pH fluctuated between 3.4 - 3.6and 4.1 - 4.4which indicated that these pHs were favour to ethanol type fermentation.Therefore , the continuous mixed attached growth reactor ( CMAGR ) could be a promising attached growth system for biohydrogen fermentation.

TREATMENT OF INDUSTRIAL WASTEWATER FROM AN ALUMINA PLANT BY MEMBRANE TECHNOLOGY(Ⅱ) ——Study on Technological Process

The experimental results of producing deionized water for the themoelectric factory from two types of the industrial wastewater of an alumina plant by using membrane technology are reported in this paper. For the treatment of the industrial wastewater with high salinity and pH value, the combination of electrodialysis (ED) and reverse osmosis (RO) is utilized, while for the treatment of the low salinity wastewater with low pH value, RO is directly used. The research results show that the above mentioned methods are effective. The technological process of the wastewater treatment with the capacity of 120 tons is designed on the basis of the experimental results.

Wastewater Pollution Abatement in China: A Comparative Study of Fifteen Industrial Sectors from 1998 to 2010

This study analyzes the management of wastewater pollutants in a number of Chinese industrial sectors from 1998 to 2010. We use decomposition analysis to calculate changes in wastewater pollutant emissions that result from cleaner production processes, end-of-pipe treatment, structural changes in industry, and changes in the scale of production. We focus on one indicator of water quality and three pollutants: chemical oxygen demand (COD), petroleum, cyanide, and volatile phenols. We find that until 2002, COD emissions were mainly reduced through end-of-pipe treatments. Cleaner production processes didn’t begin contributing to COD emissions reductions until the introduction of a 2003 law that enforced their implementation. Petroleum emissions were primarily lowered through cleaner production mechanisms, which have the added benefit of reducing the input cost of intermediate petroleum. Diverse and effective pollution abatement strategies for cyanide and volatile phenols are emerging among industries in China. It will be important for the government to consider differences between industries should they choose to regulate the emissions of specific chemical substances.

Effect of sulfate on the methanogenic activity of a bacterial culture from a brewery wastewater during glucose degradation

The maximum specific methanogenic activity （SMA） of a sludge originating from a brewery wastewater treatment plant on the degradation of glucose was investigated at various levels of sulfate on a specific loading basis. Batch experiments were conducted in serum bottles at pH 7 and 35℃. A comparison of the values indicates that the SMA of this mixed culture was increased and reached its highest level of 0.128 g CH4 gas COD/（g VSS.d） when biomass was in contact with sulfate at a ratio of 1：0.114 by weight.

Pretreatment of apramycin wastewater by catalytic wet air oxidation

The pretreatment technology of wet air oxidation(WAO) and coagulation and acidic hydrolysis for apramycin wastewater was investigated in this paper. The COD, apramycin, NH^+_4 concentration, and the ratio of BOD_5/COD were analyzed, and the color and odor of the effluent were observed. WAO of apramycin wastewater, without catalyst and with RuO_2/Al_2O_3 and RuO_2-CeO_2/Al_2O_3 catalysts, was carried out at degradation temperature of 200℃ and the total pressure of 4 MPa in a 1 L batch reactor. The result showed that the apramycin removals were respectively 50 2% and 55 0%, COD removals were 40 0% and 46 0%, and the ratio of BOD_5/COD was increased to 0 49 and 0 54 with RuO_2/Al_2O_3 and RuO_2-CeO_2/Al_2O_3 catalysts in catylytic wet air oxidation(CWAO) after the reaction of 150 min. With the pretreatment of coagulation and acidic hydrolysis, COD and apramycin removals were slight decreased, and the ratio of BOD_5/COD was increased to 0 45, and the effluents was not suitable to biological treatment. The color and odor of the wastewater were effectively controlled and the reaction time was obviously shortened with WAO. HO_2· may promote organic compounds oxidized in WAO of the apramycin wastewater. The addition of CeO_2 could promote the activity and stability of RuO_2/Al_2O_3 in WAO of apramycin wastewater.

Microbial Electrolysis Cells for Hydrogen Production

Microbial electrolysis cells(MECs)present an attractive route for energy-saving hydrogen(H2)production along with treatment of various wastewaters,which can convert organic matter into H2 with the assistance of microbial electrocatalysis.However,the development of such renewable technologies for H2 production still faces considerable challenges regarding how to enhance the H2 production rate and to lower the energy and the system cost.In this review,we will focus on the recent research progress of MEC for H2 production.First,we present a brief introduction of MEC technology and the operating mechanism for H2 production.Then,the electrode materials including some typical electrocatalysts for hydrogen production are summarized and discussed.We also highlight how various substrates used in MEC affect the associated performance of hydrogen generation.Finally we presents several key scientific challenges and our perspectives on how to enhance the electrochemical performance.

TREATMENT OF INDUSTRIAL WASTEWATER FROM AN ALUMINA PLANT BY MEMBRANE (Ⅰ) ——Measurement of Limiting Current Density of Electrodialysis

In order to design the technological process of desalination by electrodialysis for the industrial wastewater of an alumina plant, the limit current density of the industrial wastewater is measured, and the equations of limit current density, voltage drop of the unit membrane pair at the limiting current and desalination ratio at the limiting current were obtained.

Photocatalytic fuel cell for simultaneous antibiotic wastewater treatment and electricity production by anatase TiO_(2) nanoparticles anchored on Ni foam

Photocatalytic fuel cell (PFC) holds great potential for the sustainable production of electricity and degradation of organic pollutants for solving global energy and environmental problems.However,the efficient photodegradation of organic dyes and antibiotic drugs,such as ciprofloxacin (CIP) and methylene blue(MB),remains challenging.Aiming at improving the separation efficiency of hole and electron for electricity generation in the PFC system,TiO_(2)-NPs@NF-x photoanode was fabricated by a cost-effective and laborsaving hydrothermal approach.The as-fabricated photoanode demonstrated abundant active sites,enhanced light harvesting capacity and photogenerated charge carrier separation.At a CIP-HCl concentration of 10 mg/L and p H value of about 7,85%of CIP-HCl can be efficiently removed after 3 h irradiation by 300 W Xe lamp.TiO_(2)-NPs@NF-20 photoelectrode based PFC system exhibited an impressed ability to simultaneously degrade ciprofloxacin and generate electricity under light irradiation with an open circuit voltage of 1.021 V,short circuit current density and maximum power density of 2.4 mA/cm^(2),0.357 mW/cm^(2),respectively.This work provided a cost-effective method for the treatment of organic waste and generation of electrical power.

三维变形管MVR蒸发器用于纤维素生产末端废水零排放项目

蒸发器的换热性能对机械蒸汽再压缩(MVR)系统投资及运行均有着重要影响。MVR蒸发器的管内传热与压降性能在基于三维变形管和直圆管的情况下存在明显差异。建立了考虑盐水浓度修正的三维变形管MVR蒸发器性能准则关联式,设计一套用于纤维素生产末端废水零排放项目的新型蒸发器。应用实践表明,相对于传统直圆管的MVR蒸发器,基于三维变形管的新型MVR蒸发器节材节能效果显著,其在节省29%换热面积的情形下仍能完全满足工程实际需要。在现场调研期间MVR系统处理每吨废水的压缩机耗电量在18.81~23.78 kW∙h之间,体现出新型蒸发器高能效的技术特性,极具应用推广价值。

光伏企业生产废水处理工程实例

根据光伏企业生产废水水质特征,按照分类收集、分质处理原则,将含氟废水经混凝沉淀预处理后再与综合废水合并,采用电催化-混凝沉淀-管式微滤-UASB-AO组合工艺进行处理。运行结果表明,该工艺对光伏企业综合废水中的污染物有较高的去除率,对F^(-)、COD_(Cr)、BOD_(5)、NH_(4)^(+)-N、TN和SS的最终去除率分别达到了89.1%、97.6%、96.5%、90.6%、84.3%和85.3%,出水水质可以达到《电池工业污染物排放标准》(GB 30484—2013)表2新建企业水污染物间接排放标准要求,工程投资共计797万元,运行费用为8.36元/t,通过沼气回收、磁悬浮风机节能技术,每年产生经济效益为34.0万元,为光伏企业生产废水的设计与运行处理提供参考。