Catalytic oxidation with Al-Ce-Fe-PILC as a post-treatment system for coffee wet processing wastewater

The effluent from the anaerobic biological treatment of coffee wet processing wastewater (CWPW) contains a non-biodegradable compound that must be treated before it is discharged into a water source. In this paper, the wet hydrogen peroxide catalytic oxidation (WHPCO) process using Al-Ce-Fe-PILC catalysts was researched as a post-treatment system for CWPW and tested in a semi-batch reactor at atmospheric pressure and 25 °C. The Al-Ce-Fe-PILC achieved a high conversion rate of total phenolic compounds (70%) and mineralization to CO(2) (50%) after 5 h reaction time. The chemical oxygen demand (COD) of coffee processing wastewater after wet hydrogen peroxide catalytic oxidation was reduced in 66%. The combination of the two treatment methods, biological (developed by Cenicafé) and catalytic oxidation with Al-Ce-Fe-PILC, achieved a 97% reduction of COD in CWPW. Therefore, the WHPCO using Al-Ce-Fe-PILC catalysts is a viable alternative for the post-treatment of coffee processing wastewater.     

豫园荷花池换水前后水质对比及其恶化原因探讨

通过对上海豫园荷花池换水前后水质进行监测对比,查找水质恶化的原因。经过分析比较发现荷花池在换水之后,水质并没有象预想的那样得到好转,反而水质有比原来更差的趋势。因此,荷花池水质恶化的主要原因可能是由于外源引起的,对此给出了一些治理和改善水质的建议。     

Seasonally loaded waste stabilisation ponds: a novel application for intermittent discharge

This research examined the use of a single facultative pond for treatment of an intermittent discharge from a UK campsite. The system was monitored over an 11-month period to determine the optimum time for discharge in terms of quality standards. The results showed that based on organic strength, discharge was possible in winter between November and March but February was the optimum to meet nutrient and suspended solids requirements. The pond showed rapid acclimatisation to the influent wastewater, with biochemical oxygen demand removal rates during the filling period of around 60 kg ha(-1) day(-1) and removal efficiencies of ～95% after maturation. The system proved simple to operate. A major design factor is the requirement for storage of net incoming precipitation, which may provide dilution of residual pollutants but requires additional system capacity.     

天津市主要地表河流污染物特性变化趋势分析

以天津市14条主要地表河流2004-2011年期间的高锰酸盐指数、化学需氧量、五日生化需氧量、氨氮、石油类、挥发酚、总磷7项污染物含量为依据,对天津市主要地表河流的污染特性、差异性及变化趋势进行分析。结果表明:高锰酸盐指数、化学需氧量、五日生化需氧量和氨氮这4种污染物含量的均值从2004-2011年总体呈下降趋势;石油类含量不同年间变化不大;挥发酚和总磷呈典型的W型变化趋势。7种污染物含量均值在同一年不同水期有一定的差异性,但差异不显著。本研究补充了天津市多条主要河流连续多年水质情况分析统计的数据,研究结果可为天津市水环境污染防治、保护和治理提供依据。     

Performance of a pilot-scale high rate algal pond system treating abattoir wastewater in rural South Australia: nitrification and denitrification.

As part of a study examining the efficacy of high-rate algal pond treatment of high-strength abattoir wastewater, the impact of pond configuration and loading rate on nitrification was determined. The extent of nitrification in all ponds was consistent with mass balance estimates of oxygen demand and availability. Deeper ponds were more stable nitrifying systems, with shallow ponds displaying greater variation in response to changes in nitrogen loading. In a separate experiment the pond system was modified by covering a part of an in-series HRAP to exclude light, providing conditions suitable for denitrification. Specific denitrification rates were often within the range typical for endogenous carbon sources, with mass balance calculations indicating removals of up to 95%.     

Sustainability of Natural and Mechanized Aerated Ponds for Domestic and Municipal Wastewater Treatment in Palestine

Abstract

More than half of the current wastewater treatment facilities constructed in Palestine are waste stabilization ponds (WSP) and have several problems in their operation. This article evaluates three selected case studies on the various pond systems including WSP, algae- and duckweed-based ponds (ABP and DBP, respectively) and one mechanically aerated lagoon (AL) system. The effects of various design and operating parameters on the pond system' performance, with special emphasis on nitrogen removal, are discussed. The effluent quality of WSP and AL complies only with BOD limits, but not with microbiological limits prescribed for agricultural purposes, as determined by national standards. ABP and DBP achieved nitrogen removal only under high surface area demand (5-7 m2capita-1). Suitable plans for modifying existing aerated lagoons or for upgrading natural lagoons are suggested in order to comply with microbiological standards for effluent use in restricted irrigation. Finally, the suggested sustainability criteria for the evaluated pond systems may help the decision makers, as well as their designers and donor countries, to better select and design low-cost treatment options for sustainable wastewater management in developing countries.     

Influence of annual climate variability on design and operation of waste stabilisation ponds for continental climates.

WSPs are widely used in North America, and offer huge potential for other continental climate regions. The standard design and operating protocol is robust even at high latitudes, but may be conservative elsewhere. A simple model based on first-order kinetics for biochemical oxygen demand (BOD) is used to consider some alternative design and operating protocols, using long-term daily climate records for cities across continental central Asia. Options include changing the discharge period; retaining treated water in the pond over the winter; and changing the facultative pond loading. Annual variability in climate parameters has a major effect, in particular on the date at which treated wastewater meets appropriate standards for discharge or re-use: the earlier the discharge, the greater the variability in effluent quality. Skilful management of these systems may therefore be required to maximise their performance. While current models require development, it is clear modelling could provide tools and guidelines that would allow the design of continental climate WSP to be tailored to specific regional and local climate conditions.     

苏南运河对太湖主要入湖河流污染物通量的贡献率

为了解苏南运河对太湖主要入湖河流污染物通量的贡献,基于一维平原河网水量、水质数学模型,模拟计算了2011年受苏南运河影响的主要入湖河流的入湖污染物通量(COD、氨氮、TN、TP),量化分析了苏南运河对主要入湖河流入湖污染物通量的贡献率。研究结果表明:苏南运河主要影响湖西区的太湖主要入湖河流,对湖西区主要入湖河流入湖通量的总体贡献率约为23%,其中对太滆运河的贡献率最大,约42%,漕桥河次之,约23%,对太滆南运河、社渎港、陈东港污染物通量的贡献率由北向南依次减小。     

Pollutant removal in a multi-stage municipal wastewater treatment system comprised of constructed wetlands and a maturation pond, in a temperate climate

A multi-stage municipal wastewater treatment system is proposed to comply with Mexican standards for discharge into receiving water bodies. The system is located in Santa Fe de la Laguna, Mexico, an area with a temperate climate. It was designed for 2,700 people equivalent (259.2 m3/d) and consists of a preliminary treatment, a septic tank as well as two modules operating in parallel, each consisting of a horizontal subsurface-flow wetland, a maturation pond and a vertical flow polishing wetland. After two years of operation, on-site research was performed. An efficient biochemical oxygen demand (BOD5) (94-98%), chemical oxygen demand (91-93%), total suspended solids (93-97%), total Kjeldahl nitrogen (56-88%) and fecal coliform (4-5 logs) removal was obtained. Significant phosphorus removal was not accomplished in this study (25-52%). Evapotranspiration was measured in different treatment units. This study demonstrates that during the dry season wastewater treatment by this multi-stage system cannot comply with the limits established by Mexican standards for receiving water bodies type 'C'. However, it has demonstrated the system's potential for less restrictive uses such as agricultural irrigation, recreation and provides the opportunity for wastewater treatment in rural areas without electric energy.     

3种微藻在龟鳖养殖废水中的生长与脱氮除磷特性

选取小球藻(Chlorella sp.)、栅藻(Scenedesmus sp.)和螺旋藻(Spirulina sp.)为试验藻种,分别接种于经沉淀池初步处理后排放的龟鳖养殖废水(取自无为县某养殖场,简称WW废水)和无任何处理直接排放的龟鳖养殖废水(取自大杨镇某养殖场,简称DY废水),考察3种微藻生长特性和对废水中氮磷的去除效果,比较其对龟鳖养殖废水的净化能力。结果表明:所选的3种微藻在两种废水中生长特性不同,DY废水中3种微藻细胞密度与生物量均大于其在WW废水中的相应指标,DY废水中小球藻、栅藻和螺旋藻的最大生物量分别为0.26 g/L、0.28 g/L和0.20 g/L。不同微藻对废水中氮磷去除效果各不相同,栅藻去除TN效果最好,最大去除率为93.65%,小球藻去除TP效果最好,最大去除率为99.46%,螺旋藻去除NH+4-N效果最好,最大去除率为98.79%。     

苏州市东山镇池塘养蟹面源污染现状及控制

结合全国污染源普查活动,以苏州市养殖老区东山镇养殖池塘为典型,调查其现行养殖模式、经济效益、养殖污染状况。调查结果显示,东山镇现有养殖面积为2 253.33 hm2,主养品种为河蟹。1个养殖周期中,养殖池塘通过沟渠排入外界的TN、TP含量分别平均为21.25 kg/hm2、2.34 kg/hm2;密度为9 000只/hm2的低密度养殖池外排的TN含量为16.79 kg/hm2,而无TP排出。分析苏州地区池塘养殖产生水环境污染的主要原因,从池塘管理体制改革、科学生态养殖技术及养殖尾水处理等方面探讨池塘养殖污水零排放技术,为苏州市养殖业面源污染的控制提供对策和措施。     

太湖流域某养殖池塘水平衡分析和水生态模拟

为解决传统池塘养殖产生的环境污染问题，应用水生态模型对养殖池塘水生态环境进行模拟。以太湖流域 某养殖池塘为例，通过水量平衡分析得到具体补排水时间序列，输入 AQUATOX 水生态模型软件进行建模，经过 率定验证后进行控制模拟，针对投饵率对水质与养殖品之间的相互影响规律进行探讨。结果表明：基于降雨-水位 的补排水识别方法能弥补具体补排水量的测量空白；饵料对研究池塘水质影响较大，在 1%~7% 的投饵率梯度中， 随着投饵率的增加，TP、TN 和氨氮质量浓度整体上大幅增加；以养殖品安全质量浓度为界，在 1%~7% 的投饵率 梯度内养殖品产量随氨氮质量浓度的增加呈现先增后减的趋势。该研究建立的水生态系统模型模拟效果较好， 综合考虑保持良好的水生态环境与经济成本，该池塘养殖中的建议投饵率为 2.5%~3.0%。     

天津某校园全年雨雪水质监测及污染成因

为降低雨水资源化利用成本, 保证可利用雨水水质, 弃流水质较差的初期降雨及特殊场次降雨成为目前雨水资源化利用的重要途径。因此需要通过长期连续监测降雨和降雪中氮、磷和化学需氧量等关键指标的变化, 确定合理的雨水弃流方式。以天津大学北洋园校区为研究区, 对该区域 2018 年 1- 12 月的降雨和降雪水质进行连续监 测。结果表明: 2018 年 3 月和 4 月降雨中氨氮( 6.75 mg / L) 、总氮( 9.36 mg/ L) 的平均质量浓度分别是全年降雨和 降雪中氨氮和总氮平均质量浓度的 1.5 和 2.1 倍; 春季首场降雨中污染物平均质量浓度远超冬季首场降雪, 冬季空气污染是导致春季首场降雨水质差的主要原因; 空气中各污染物质量浓度对降雨和降雪水质的影响由大到小依次 为 PM215 > PM10 > NO2 > SO2 > CO> O3_8h。与其他季节相比, 春季前两场降雨污染物平均质量浓度高、降水量小, 雨水利用处理成本高, 建议将春季前两场降雨( 降水量< 10 mm) 直接弃流至污水处理厂, 不宜直接进入雨水资源化利用设施。     

考虑水质与水价影响的城市再生水需求研究

再生水是城市的“第二水源”,加强再生水配置利用对优化供水结构、增加水资源供给、缓解水量供需矛盾以及保障水生态安全具有重要意义。科学预测城市再生水需求是提高污水资源化利用水平的重要基础。在区域水资源需求分析基础上,充分考虑工业生产、城市杂用、河道补水、农林灌溉等4大领域的水量和水质需求特点,提出考虑水质与水价的分领域再生水需求预测技术框架。首先考虑水质影响,引入再生水可替代率指标,分析水资源需求总量中可由再生水供给的水量;其次,考虑自主定价模式下再生水价格对用户需求的影响,建立“补贴-价格-需求”模型,计算不同补贴情景下区域再生水的需求量;最后,应用于宿迁市中心城市。结果表明：在规划年2025和2030年的再生水利用率目标要求下,采用中等补贴情景能在有效推广再生水利用的同时兼顾政府财政压力,再生水需求量分别可达10 095×10⁴和13 387×10⁴ m³。本研究进一步拓展了城市再生水需求量预测的理论方法,也为宿迁市再生水利用配置提供了科学依据。     

Application of WASP model to simulate water pollution control of Duriangkang Dam

Located in Batam City, Duriangkang Dam plays an essential role in providing clean water in the area, also being the first and largest estuary dam in Indonesia. However, with a total effective water volume of 107,000,000 m³, Duriangkang Dam is now heavily polluted because of enormous wastewater loads from both domestic and industrial sources that are directly discharged into the dam. The practice of fish farming has also contributed to its demise. Based on water samples collected during 2016 to 2018, the water condition for Duriangkang Dam is no longer classified as the 2nd class of raw water, based on Indonesian water standards. The present study utilizes the WASP model to evaluate and simulate possible solutions for controlling the Duriangkang Dam water pollution rate. The water quality indicators of dissolved oxygen (DO), total phosphorus (TP) and biochemical oxygen demand (BOD) concentrations are modelled. The calibration and verification results indicate the model exhibited an excellent fitting for DO, BOD and TP concentrations. Under several scenarios, it was determined that the best way to control the pollution rate within the dam is by implementing scenario 8, which include total control of the fish farms and domestic wastewater loads.     

Dynamic variation of supernatant quality in a dairy shed waste stabilisation pond system.

An intensive monitoring program of a standard two-stage dairy shed waste stabilisation pond system was undertaken to determine the incidence and extent of spatial and temporal variation of basic physio-chemical parameters, and to shed light on the longer term dynamic nature of in-pond conditions. The anaerobic-facultative pond system, located in a remote rural area, treats wastewater from the hosing down and hydraulic flushing of the milking parlour and holding yard at the farm dairy shed. A number of multi-parameter water quality field monitoring probes were permanently deployed at various locations within the two ponds to enable continuous measurement of temperature, pH, conductivity and dissolved oxygen. In addition, profiling of the supernatant of both ponds was undertaken at different times of the year to examine vertical variation of the same parameters. Continuous monitoring revealed spatial homogeneity in EC and pH levels in the upper metre of both ponds. Physio-chemical parameters also appear to change uniformly across the ponds in response to external stimuli such as rainfall. Neither pond, however, exhibits homogeneity down the profile of the supernatant. Seasonal stratification is prevalent in the facultative pond suggesting poor vertical mixing, while the anaerobic pond is notably affected by sludge accumulation. A long-term pattern of rising conductivity in both ponds indicated accumulation of dissolved salt species in the system due to recirculation of reclaimed effluent for hydraulic flushing of the dairy shed. In the facultative pond, diurnal fluctuations in dissolved oxygen, oxidation-reduction potential and turbidity during warmer months of the year closely followed temperature swings. The extensive data collected in this study provides a detailed picture of the physio-chemical dynamics of two-stage stabilisation pond systems treating dairy shed wastewater.     

Assessment of physico‐chemical properties of water and phytoplankton bloom formation in a eutrophic pond using multivariate analysis

An investigation of the water chemistry and phytoplankton bloom formation characteristics of a seasonal earthen pond located in the Alappuzha District, Kerala (India) was carried out during November 2011 to May 2012. Twelve important physico‐chemical parameters (temperature, Secchi disc transparency, pH, electrical conductivity EC), dissolved oxygen (DO), biochemical oxygen demand (BOD), ammonia‐nitrogen, nitrite‐nitrogen, nitrate‐nitrogen, total phosphorus (TP), dissolved iron and chlorophyll a related to phytoplankton growth in the pond were the focus of the present study. Chlorophyll a was used as a measure of phytoplankton biomass. The pond developed subsurface phytoplankton blooms of Chlorella vulgaris, Aphanothece sp., Leptosira sp., Lepocinclis globulus and Lepocinclis fusiformis. Visible scums of Lepocinclis globulus and Euglena proxima was also observed during March 2012. Principal component analysis was performed to understand the biochemical processes in the pond ecosystem leading to the Euglena spp. bloom.     

Treated wastewater use in Saudi Arabia: challenges and initiatives

The Kingdom of Saudi Arabia considers treated wastewater a major water source and aims to achieve 100% use of treated wastewater by 2025. This article reviews Saudi Arabia’s treated wastewater utilization status to date. It also highlights the key challenges facing the authorities, such as the substantial growth in demand for wastewater services; low coverage of the existing wastewater collection, treatment, and treated wastewater use systems; and the capital investment needed for infrastructure development. Finally, the article highlights the initiatives taken thus far to tackle these challenges and recommends further initiatives towards successful achievement of Saudi Arabia’s treated wastewater utilization objective.     

Overview of USEPA/CLEAR Lake Erie Sediment Oxygen Demand Investigations During 1979

In situ hypolimnetic oxygen depletion measurements were conducted during four summer cruises in 1979 at two central basin stations in Lake Erie to evaluate the relative contribution of the sediments to the oxygen demand. Sediment oxygen demand (SOD) rates were determined by measuring the rate of oxygen decrease within a triangular benthic chamber; water column oxygen demand (WOD) rates were determined using 24-hour light and dark bottles placed in situ. Results indicated that the SOD contribution to the hypolimnetic oxygen depletion rate decreased throughout the summer from about 81% to only 30% with an initially high rate due to spring algal biomass sedimentation and lower rates in late summer due to depressed oxygen levels. The WOD rate contribution increased from 19% to 70% throughout the stratified period due to the decomposition of settling algal cells. Comparing the overall volumetric summer in situ rates (0.126 mg O₂/L/day) with cruise-interval depletion rates (0.365 mg O₂/L/day), the in situ rates were about 300% higher. This is attributed to unaccounted oxygen sources to the hypolimnion and because the in situ rates measure the gross WOD and SOD rather than measuring the net effects they exert.     

生态塘对稻田降雨径流中氮磷的拦截效应研究

农田养分的大量流失已成为农业面源污染的主要来源之一,生态塘兼具排水和生态湿地双重功效,研究其对稻田排水氮磷的拦截效应对于防治农业非点源污染具有重要意义。针对降雨径流条件下生态塘对降雨径流中氮磷的动态拦截效应以及降雨径流结束后氮磷在静水中的去除效应有待明了的需求,本文选取太湖西岸何家浜流域典型农田作为研究对象,并将该区域的塘堰改造为生态塘,研究了生态塘对水稻生长期内的三场降雨径流氮磷的拦截去除效果及降雨径流结束后氮磷在静水中的去除效应。研究结果表明:(1)在三场降雨过程中,生态塘对总氮(TN)的平均去除率为34.7%,总磷(TP)的平均去除率为34.8%;(2)生态塘对降雨径流中不同形态氮磷的去除率大小排序为氨氮(NH_4~+-N)颗粒态氮(PN)硝态氮(NO_3~--N),颗粒态磷(PP)溶解态磷(DP),且径流状态下水体垂向分层氮磷浓度分布随降雨进行而变化,总体分布规律为底层氮磷浓度大于表层氮磷浓度;(3)降雨径流结束后,TN在生态塘中的去除率为50.4%,TP在生态塘中的去除率为52.3%,塘2对TN、TP的去除率大于塘1与塘3,生态塘表现了较强的抗冲击自修复性。