Quality of wastewater reuse in agricultural irrigation and its impact on public health

This study is planned to perform a sanitary survey of the largest sewage treatment plant in Riyadh, KSA, fortnightly for 6 months to examine its effluent quality as an example for the growing dependence on reuse of treated municipal wastewater in agricultural irrigation purposes to cope with increasing water shortage. The biological and physico-chemical parameters of 12 wastewater samples from the plant were examined using standard methods. The physico-chemical analysis indicated that the surveyed municipal wastewater treatment plant contained some of the studied parameters, such as turbidity, total suspended solids, biochemical oxygen demand, chemical oxygen demand and residual chlorine above the maximum permissible wastewater limits set by the Saudi Standards. However, heavy metal concentrations in all samples were lower than the recommended standards. Total and faecal coliform counts were above the permissible limits indicating poor sanitation level. Fifty percent of all wastewater samples were contaminated with faecal coliforms but, surprisingly, Escherichia coli were only detected in 8.3 % of the samples. Regular monitoring and enhancement of microbial and physico-chemical parameters of the wastewater quality served by different wastewater treatment plants for reuse in agricultural irrigation is recommended to preserve the environment and public health.     

Analysis of the environmental impact on a stream: is only tannery to blame?

The contribution of wastewater from a tannery industry to the pollution of a stream was investigated. The main parameters studied were biochemical oxygen demand, chemical oxygen demand, chromium, dissolved oxygen, fecal and total coliforms, nitrogen, oils and greases, pH, phosphorous, sulfides, suspended solids, turbidity, and volatile solids. Three sampling points were located: (1) at the discharge point of tannery wastewater, (2) 50 m upstream, and (3) 80 m downstream of discharge point. Also was investigated the pollution at the stream source.     

The use of a natural coagulant (Opuntia ficus-indica) in the removal for organic materials of textile effluents

The goal of this study was to investigate the activity of the coagulant extracted from the cactus Opuntia ficus-indica (OFI) in the process of coagulation/flocculation of textile effluents. Preliminary tests of a kaolinite suspension achieved maximum turbidity removal of 95 % using an NaCl extraction solution. Optimization assays were conducted with actual effluents using the response surface methodology (RSM) based on the Box–Behnken experimental design. The responses of the variables FeCl₃, dosage, cactus dosage, and pH in the removal of COD and turbidity from both effluents were investigated. The optimum conditions determined for jeans washing laundry effluent were the following: FeCl₃ 160 mg L^?1, cactus dosage 2.60 mg L^?1, and pH 5.0. For the fabric dyeing effluent, the optimum conditions were the following: FeCl₃ 640 mg L^?1, cactus dosage 160 mg L^?1, and pH 6.0. Investigation of the effects of the storage time and temperature of the cactus O. ficus-indica showed that coagulation efficiency was not significantly affected for storage at room temperature for up to 4 days.     

Physicochemical quality of an urban municipal wastewater effluent and its impact on the receiving environment

The physicochemical qualities of the final effluents of an urban wastewater treatment plant in South Africa were assessed between August 2007 and July 2008 as well as their impact on the receiving watershed. The pH values across all sampling points ranged between 6.8 and 8.3, while the temperature varied from 18°C to 25°C. Electrical conductivity (EC) of the samples was in the range of 29–1,015 μS/cm, and turbidity varied between 2.7 and 35 NTU. Salinity and total dissolved solids (TDS) varied from 0.36 to 35 psu and 16 to 470 mg/L, respectively. The concentrations of the other physicochemical parameters are as follows: chemical oxygen demand (COD, 48–1,180 mg/L); dissolved oxygen (DO, 3.9–6.6 mg/L); nitrate (0.32–6.5 mg NO $_{3}^{-}$ as N/L); nitrite (0.06–2.4 mg NO $_{2}^{-}$ as N/L); and phosphate (0.29–0.54 mg PO $_{4}^{3-}$ as P/L). pH, temperature, EC, turbidity, TDS, DO, and nitrate varied significantly with season and sampling point (P?<?0.05 and P?<?0.01, respectively), while salinity varied significantly with sampling point (P?<?0.01) and COD and nitrite varied significantly with season (P?<?0.05). Although the treated effluent fell within the recommended water quality standard for pH temperature, TDS, nitrate and nitrite, it fell short of stipulated standards for other parameters. The result generally showed a negative impact of the discharged effluent on the receiving watershed and calls for a regular and consistent monitoring program by the relevant authorities to ensure best practices with regard to treatment and discharge of wastewater into the receiving aquatic milieu in South Africa.     

Physicochemical characteristics of paper industry effluents��a case study of South India Paper Mill (SIPM)

Pulp and paper mills generate varieties of pollutants depending upon type of the pulping process being used. This paper presents the characteristics of wastewater from South India Paper Mill, Karnataka, India which is using recycled waste paper as a raw material. The raw wastewater consists of 80?C90 mg L^???1 suspended solid and 1,010?C1,015 mg L^???1 dissolved solid. However, pH varied from 5.5?C6.8. The biochemical oxygen demand and chemical oxygen demand ranged from 200?C210 and 1,120?C1,160 mg L^???1, respectively. Aerobic treatment of raw effluent attribute to significant reduction in suspended solid (range between 25 to 30 mg L^???1) and total dissolved solid (range between 360 to 390 mg L^???1). However, pH, temperature, and electrical conductivity were found superior after treatment. Copper, cadmium, iron, lead, nickel, and zinc were found in less quantity in raw effluent and were almost completely removed after treatment. The dendrogram of the effluent quality parameters clearly indicate that South India Paper Mill does not meet Minimal National Standard set by central Pollution Control Board to discharge in agricultural field.     

Evaluation of pollution load of Lahore Canal by quantification of various pollutants through physicochemical characterisation

The work describes the physicochemical analysis of the water samples collected from Lahore Canal to evaluate pollution load at different points of the canal. Different physical and chemical pollutants such as temperature, pH, electrical conductivity, total dissolved and suspended solids, turbidity, chlorides, sulphates, nitrates, oils and grease, dissolved oxygen, chemical oxygen demand and biological oxygen demand (BOD) were analysed. The data was analysed through analysis of variance, which showed that the p values for dissolved oxygen (DO), chemical oxygen demand (COD), BOD, electrical conductivity, total dissolved solid (TDS), total suspended solid (TSS), turbidity, oil and grease, sulphates, and nitrates are <0.05, while p value of temperature, pH, and chlorides are 1.000, 0.984, and 0.070, respectively, which are >0.05. Further regression analysis revealed that the simple line regression modal is fit for turbidity and TSS, electrical conductivity and TDS, COD and DO, BOD and DO, and BOD and COD. The studies reveal that Lahore Canal is receiving a considerable amount of physical and chemical pollutants at different points.     

EOX concentrations in sediment in the part of the Bothnian Bay affected by effluents from the pulp and paper mills at Kemi, Northern Finland

The Bothnian Bay, which is the northernmost part of the Gulf of Bothnia in Northern Finland, is affected by effluents discharged from point sources such as the pulp and paper mills of Stora Enso Oyj Veitsiluoto Mill and Oy Metsä-Botnia Ab Kemi Mill at Kemi, and the Kemi municipal sewage plant, as well as the River Kemijoki. In this paper we discuss, how modernisation of the wastewater treatment plant at the mills, and process investments in the Best Available Techniques (BAT) for effluent treatment, have decreased the effluent discharges of biological oxygen demand (BOD), chemical oxygen demand (COD), total phosphorus (Tot-P), total nitrogen (TOT-N), total suspended solids (TSS) and adsorbable organically bound halogens (AOX) from the mills since 1988. One specific aim of the study was to determine the EOX (Extractable Organically Bound Halogens) concentrations in bottom sediment of the Bothnian Bay in order to assess whether the EOX concentrations reflect the reduction in discharges of chlorinated compounds. According to the monitoring program carried out every third year between 1997–2006, the decreasing trend in EOX concentrations in the top 2 cm of the bottom sediment reflect the decrease in organochlorine discharges (AOX) from the mills. In 1997 the EOX concentrations in bottom sediment varied between 3–70 μg of Cl g^?1 (dry weight), and in 2006 between 3.3–32 μg of Cl g^?1 (dry weight).     

纺织印染废水中TOC值和COD值的相关性

论证了纺织印染废水中TOC值和COD值的相关性,建立了COD和TOC的相关关系式。通过对实测的TOC值和COD值进行的一系列数理统计显著性检验,证实了纺织印染废水中TOC值和COD值之间具有良好的相关性,但基于生产过程、设施装置和排污情况的差异,印染企业在运用COD和TOC的相关关系式时,应根据自身的具体情况,通过实验建立相应的回归方程。     

Process parameters for decolorization and biodegradation of orange II (Acid Orange 7) in dye-simulated minimal salt medium and subsequent textile effluent treatment by Bacillus cereus (MTCC 9777) RMLAU1

In this study, Bacillus cereus isolate from tannery effluent was employed for orange II dye decolorization in simulated minimal salt broth and textile effluent. Most of the physicochemical parameters of textile effluent were above the permissible limits. The strain was highly tolerant to dye up to 500 mg l^?1. Increasing dye concentration exerted inhibitory effect on the bacterial growth and decolorization. The maximum decolorization of initial 100 mg dye l^?1 was achieved at optimum pH 8.0 and 33 °C under static culture conditions during 96-h incubation. Supplementation with optimized glucose (0.4 %, w/v) and ammonium sulfate (0.1 %, w/v) with 3.0 % B. cereus inoculum further enhanced dye decolorization to highest 68.5 % within 96-h incubation. A direct correlation was evident between bacterial growth and dye decolorization. Under above optimized conditions, 24.3 % decolorization of unsterilized real textile effluent by native microflora was achieved. The effluent decolorization enhanced substantially to 37.1 % with B. cereus augmentation and to 40.5 % when supplemented with glucose and ammonium sulfate without augmentation. The maximum decolorization of 52.5 % occurred when textile effluent was supplemented with optimized exogenous carbon and nitrogen sources along with B. cereus augmentation. Gas chromatography–mass spectrometry identified sulfanilic acid as orange II degradation product. Fourier transform infra red spectroscopy of metabolic products indicated the presence of amino and hydroxyl functional groups. This strain may be suitably employed for in situ decolorization of textile industrial effluent under broad environmental conditions.     

Dynamics of industrial waste stabilization pond treatment process

Waste stabilization pond is an artificial ecosystem; its performance is governed by the nature of the biological communities it supports. These are primarily used as secondary effluent treatment plants to polish the effluents. However, they are also used to treat the raw sewage and industrial effluents. In the present study, the functioning of a waste stabilization pond system from an industrial complex located in Goa was taken up. The raw waste released by the industrial complex and the final effluent released from the stabilization ponds were analyzed for pH, dissolved oxygen (DO), biological oxygen demand, phosphate content, chlorophyll content, and algal diversity and density. Also, the activities of the enzymes catalase and phosphatase were measured. The study was carried out for a period of 1 year and the data covering pre-monsoon, monsoon, and post-monsoon seasons are tabulated. The study revealed that DO, chlorophyll content, and algal count were maximum during pre-monsoon when compared to monsoon and post-monsoon. Similarly, maximum enzymatic activity was recorded during pre-monsoon and also maximum removal of biological oxygen demand and phosphate was recorded during this period than in monsoon and post-monsoon.     

Biological treatment of textile wastewater using sequencing batch reactor technology

This study was conducted to biologically treat wastewater discharged from the textile industry (textiles made of cotton and/or synthetic fiber) using sequencing batch reactor (SBR) technology (activated sludge process operating on batch mode). To achieve the objectives of the study, the characteristics of textile wastewater and the biodegradation of its organic constituents under unsteady state conditions were studied. Then, a bench-scale pilot plant was used to study the performance of SBR by monitoring the settleability and change in the constituents (chemical oxygen demand and solids) over time. Results of the study showed that textile wastewater has different types of pollutants: heat, basicity, suspended solids, organic and inorganic matter, and heavy metals. The factors affecting the biodegradation of organic matter were determined as the reaction time and the ratio of initial substrate to sludge concentrations. Also, removal of solids was monitored, and the settling velocity as affected by sludge concentration was graphically presented to enable the determination of settling time. Finally, the outcome of this study was used to suggest a procedure for the design of a full-scale SBR unit for treatment of textile wastewater.     

Prediction of the effluent from a domestic wastewater treatment plant of CASP using gray model and neural network

When a domestic wastewater treatment plant (DWWTP) is put into operation, variations of the wastewater quantity and quality must be predicted using mathematical models to assist in operating the wastewater treatment plant such that the treated effluent will be controlled and meet discharge standards. In this study, three types of gray model (GM) including GM (1, N), GM (1, 1), and rolling GM (1, 1) were used to predict the effluent biochemical oxygen demand (BOD), chemical oxygen demand (COD), and suspended solids (SS) from the DWWTP of conventional activated sludge process. The predicted results were compared with those obtained using backpropagation neural network (BPNN). The simulation results indicated that the minimum mean absolute percentage errors of 43.79%, 16.21%, and 30.11% for BOD, COD, and SS could be achieved. The fitness was higher when using BPNN for prediction of BOD (34.77%), but it required a large quantity of data for constructing model. Contrarily, GM only required a small amount of data (at least four data) and the prediction results were analogous to those of BPNN, even lower than that of BPNN when predicting COD (16.21%) and SS (30.11%). According to the prediction, results suggested that GM could predict the domestic effluent variation when its effluent data were insufficient.     

Estimation of bacteriological levels in surface water samples to evaluate their contamination profile

The present work deals with the assessment of bacteriological contamination along with some physico-chemical parameters of water samples from Lahore canal. ANOVA showed that the observed p values of log-transformed viable plate counts, total suspended solids, turbidity, and biological oxygen demand are 0.000, 0.000, 0.000, and 0.000, respectively, which are <0.05, while the p value of total coliforms, total fecal coliforms, and Escherichia coli are 0.728, 0.827, and 0.081, respectively which are >0.05. Significant correlation was observed between log-transformed viable plate counts (CFU), biological oxygen demand, total suspended solids, and turbidity. Further regression analysis revealed that simple line regression model is fit for log-transformed viable plate counts and total suspended solids, log-transformed viable plate counts and turbidity, turbidity and total suspended solids, biological oxygen demand and total suspended solids, biological oxygen demand and log-transformed viable plate counts, and biological oxygen demand and turbidity.     

绍兴市典型印染废水中重金属锑排放现状及排放源调查

分析和统计的86家印染工业企业当中,废水总排口中的总锑超标率为25.6%,质量浓度0.050 mg/L以下较低排放浓度所占比例最大,达62.8%。印染废水锑排放源主要有涤棉和涤纶化纤类布料的染色、印花工艺废水,碱减量工艺废水等,工业液碱、废酸以及硫酸铝污水处理剂等原料当中含锑浓度较高。印染废水经污水处理厂集中纳管深度处理后,锑排放浓度较低,锑去除效率最高达到88.0%,大大降低了环境地表水体锑污染的风险。     

Assessment Of A Natural Wetland For Use In Wastewater Remediation

An environmental study was conducted to assess various aspects of the water and sediment quality of a natural wetland to determine its feasibility for advanced wastewater treatment in Louisiana. Nitrate (NO₃), nitrite (NO₂), ammonia (NH₄), total Kjeldahl nitrogen (TKN), total phosphorus, chloride, total organic carbon, pH, trace metals, fecal coliform, dissolved oxygen (DO), and biochemical oxygen demand (BOD) were monitored. Productivity of a dominant shrub, Iva frutescens, in the wetland was also assessed. Research results indicated that gradients of chloride and salinity concentrations showed a broad mixing of the discharged fresh water into the more saline natural brackish waters. This provided an ideal pattern for nutrient assimilation by the receiving marsh. NH₄ was reduced in the range of 50–100% when all combinations of sources and outflows were considered. For total phosphorus and TKN, reduction ranged from 0–95.1% and 11.2–89.7%, respectively. Some nutrient concentrations in the effluent outlet, NO₃ in particular, were lower than background concentrations found in the reference wetland. Sediment and water showed no significant deficiency or toxicity problems for the major nutrients and metals analyzed. The secondary effluent discharges had little demonstrable negative impact on the wetland during the study period from 1995 to 1996.     

运用热带爪蟾胚胎测定工业废水的发育毒性

采用热带爪蟾胚胎测定江苏省常州市8家典型行业工业废水的发育毒性,结果显示：各行业工业废水对爪蟾胚胎的发育均有不同程度的影响,而印染、啤酒、电镀和化工行业出水的发育毒性更强。试验表明,理化指标并不能完全反映工业废水的综合毒性,而热带爪蟾胚胎可有效地表征其发育毒性。比较各行业工业废水的毒性,初步探讨热带爪蟾胚胎用于工业废水毒性检测的可行性。     

Assessment of current status of zinc in wastewater treatment plants to set effluent standards for protecting aquatic organisms in Japan

New environmental standards for protecting aquatic organisms for zinc (e.g., 0.03 mg/L) in surface waters were set in Japan in 2003. Although wastewater effluent might be one of the major pathways of zinc to public water bodies in Japan, current status of concentration of zinc in wastewater effluent was not clear due to higher detection limits (e.g., 0.5 mg/L) than the level required by the new regulations. This study aims at assessing current status of zinc in wastewater effluent in Japan to revise wastewater effluent standards for protecting aquatic organisms. Survey of zinc in wastewater treatment plants (WWTPs) was carried out in Japan in 2005, setting the detection limits at least 0.01 mg/L. The results of the survey suggested the difficulty to remove zinc (especially dissolved zinc) with conventional activated sludge treatment if concentration of zinc in influent was relatively low. And it was suggested that high concentration of dissolved zinc might be derived from some industries discharging high concentration of zinc. The concentration of zinc in wastewater influent without industrial discharges was about 0.1 mg/L which might be lower than that in wastewater from industries discharging high concentration of zinc. Finally, effluent standards for point sources including WWTPs to public water bodies were set at 2 mg/L in 2006. Based on the results of the survey that it was difficult to remove dissolved zinc discharged from industries at WWTPs, the effluent standards from industries to sewerage were set at the same value of the effluent standards from WWTPs to public water bodies.     

Evaluation of violations in water quality standards in the monitoring network of São Francisco River basin,the third largest in Brazil

The São Francisco River is the largest river located entirely within Brazil, and water scarcity problems have been a major concern of Brazilian society and government. Water quality issues are also a concern and have worsened with the recent intensification of urbanization and industrialization. In this study, violations to water quality standards established by local legislation were calculated as a percentage for 26 selected parameters over a monitoring period of 14 years. The violation percentages were analyzed spatially using the Kruskal-Wallis test, followed by multiple comparison analysis. Temporal analysis was performed using the Mann-Kendall test and Spearman correlation. Some parameters could be identified as cause for concern due to high violation levels, such as the fecal coliform indicator (FCI) and phosphorus—both related to domestic and effluent disposal without treatment or with insufficient treatment—and color, turbidity, manganese, and total suspended solids—which can be affected by erosive processes of natural and anthropogenic causes. The study found that these violations are concentrated in the most urbanized and industrialized areas of the basin. Some metallic parameters, such as iron and arsenic violations, may be related to mining activities in the rich soil of the Iron Quadrangle area located within the Minas Gerais State. Trend analysis results indicated that most monitoring stations did not have significant modification (elevation or reduction) trends over time, which, together with the high violation percentages, might indicate the maintenance of a scenario of constant pressure upon water resources, in particular in those more urbanized areas.     

Radioactivity, Physical and Chemical Parameters of Underground and Surface Waters in Qua Iboe River Estuary, Nigeria

Radioactivity, physical and chemical parameters of underground boreholes and surface waters in the region of Qua Iboe River Estuary involved in oil production activities were measured. The physical and chemical parameters measured included pH, temperature, turbidity, and concentrations of total dissolved and suspended solids, dissolved oxygen, chemical and biochemical oxygen demand, oils and grease, salinity, hardness (carbonates and bicarbonates), chlorine, sulphide, and metal ions. The work reveals that the radioactivity, physical and chemical parameters determined for both the underground and surface waters are safely below the international permissible limits except that of carbonate (68.6 mg/d – 228.7 mg/l) and bicarbonate (22.9 mg/l – 76.3mg/l) which renders both sources of water hard. The exceedingly high concentration range of hydrogen sulphide (40 mg/l–440 mg/l) in both sources is also beyond the international limit of 0.05mg/l. The ammonium ion concentration (1.40–2.80mg/l) was determined to be slightly higher in both the underground and surface waters than the international limit of 0.5mg/l.     

Biodegradation of pulp and paper mill effluent by co-culturing ascomycetous fungi in repeated batch process

The competence of novel fungal consortium, consisting of Nigrospora sp. LDF00204 (accession no. KP732542) and Curvularia lunata LDF21 (accession no. KU664593), was investigated for the treatment of pulp and paper mill effluent. Fungal consortium exhibited enhanced biomass production under optimized medium conditions, i.e., glucose as carbon (C), sodium nitrate as nitrogen (N), C/N 1.5:0.5, pH 5, temperature 30 °C, and agitation 140 rpm, and significantly reduced biochemical oxygen demand (85.6%), chemical oxygen demand (80%), color (82.3%), and lignin concentration (76.1%) under catalytic enzyme activity; however, unutilized ligninolytic enzymes, such as laccase (Lac), manganese peroxidase (MnP), and lignin peroxidase (LiP), were observed to be 13.5, 11.4, and 9.4 U/ml after the third cycle of effluent treatment in repeated batch process. Scanning electron microscopy (SEM) of fungal consortium revealed their compatibility through intermingled hyphae and spores, while the FTIR spectra confirmed the alteration of functional groups ensuring structural changes during the effluent treatment. Gas chromatography/mass spectroscopy (GC-MS) analysis showed the reduction of complex compounds and development of numerous low-molecular-weight metabolites, such as 1-3-dimethyl benzene, 2-chloro-3-methyl butane, pentadecanoic acid, and 1-2-benzene dicarboxylic acid, during the treatment, demonstrating the massive potential of the novel fungal consortium to degrade recalcitrant industrial pollutants.