Effect of textile auxiliaries on the biodegradation of dyehouse effluent in activated sludge

The textile industry is confronted with serious environmental problems associated with its immense wastewater discharge, substantial pollution load, extremely high salinity, and alkaline, heavily coloured effluent. Particular sources of recalcitrance and toxicity in dyehouse effluent are two frequently used textile auxiliaries; i.e. dye carriers and biocidal finishing agents. The present experimental work reports the observation of scientific and practical significance related with the effect of two commercially important textile dye carriers and two biocidal finishing agents on biological activated sludge treatment at a textile preparation, dyeing and finishing plant in Istanbul. Respirometric measurements of the dyehouse effluent spiked with the selected textile chemicals were carried out for the assessment of the "readily biodegradable COD fraction" of the wastewater. The respirometric data obtained to visualize the effect of the selected textile auxiliaries on biomass activity was evaluated by an adopted activated sludge model. Results have indicated that the tested biocides did not exert any significant inhibitory effect on the treatment performance of the activated sludge reactor at the concentrations usually encountered in the final, total dyehouse effluent. The situation with the dye carriers was inherently different; one dye carrier appeared to be highly toxic and caused serious inhibition of the microbial respirometric activity, whereas the other dye carrier, also known as the more ecological alternative, i.e. the "Eco-Carrier", appeared to be biodegradable. Finally, the respirometric profile obtained for the Eco-Carrier was described by a simplified respirometric model.     

Phytoremediation of a sulphonated azo dye Green HE4B by <Emphasis Type="Italic">Glandularia pulchella</Emphasis> (Sweet) Tronc. (Moss Verbena)

Purpose  

The dyes and dye stuffs present in effluents released from textile dyeing industries are potentially mutagenic and carcinogenic. Phytoremediation technology can be used for remediating sites contaminated with such textile dyeing effluents. The purpose of the work was to explore the potential of Glandularia pulchella (Sweet) Tronc. to decolorize different textile dyes, textile dyeing effluent, and synthetic mixture of dyes.     

Treatment process and toxicities assessment of wastewater issued from anaerobic digestion of household wastes

Modern society grapples with large amounts of household waste. The anaerobic digestion of this waste offers a promising source for energy-rich biogas production but generates high toxic effluents that require treatment before reuse or disposal into the environment. This study aimed to investigate three techniques, namely coagulation/flocculation, electro-coagulation, and activated sludge, in terms of efficiency in the treatment of these effluents. It also aimed to assess their toxicity effects on the germination and growth of durum wheat Triticum aestivum L. seeds before and after 6 days of treatment. Activated sludge was most efficient in reducing chemical oxygen demand, turbidity, and conductivity (95.7 %, 15.8 %, and 37.5 %, respectively). The effluent treated with this technique induced a marked delay in germination (low mean time of germination) and a significant reduction in the percentages of seed germination and root and leaf growths. It was also noted to strongly induce lipid peroxidation in roots and leaves, which presumably explained the germination/growth inhibition of the wheat seeds. The effluent also induced marked lipid peroxidation effects and strongly inhibited the activities of butyrylcholinesterase in mice bone marrows. The effluent shows a high ability to inhibit the growth of three microalgae; these endpoints are useful tools to biomonitor the physico-chemical quality of this wastewater. Overall, while no significant alterations were observed in terms of animal and vegetable toxicities when the effluent was treated by coagulation/flocculation, activated sludge treatment proved efficient in reducing the toxicities induced by the untreated effluents. The results indicate that the application of this technique is promising with regards to attaining efficient, eco-friendly, and cost-effective strategies for the management and treatment of household waste.     

Mutagenicity evaluation of industrial sludge from common effluent treatment plant

Sludge from common effluent treatment plant (CETP) receiving effluents from textile industries at Mandia Road, Pali, was analyzed to assess the level of mutagenicity. Mutagenicity assay using Salmonella typhimurium tester strains TA 98 and TA 100 gave positive results, thus suggesting presence of genotoxic contaminants in the samples investigated. Further, mutagenic activity of chemical sludge was found to be lesser than that of biological sludge. This result is very surprising and unexpected as it is indicating that some mutagenic compounds are either being formed or certain promutagenic compounds are being converted into stable mutagenic metabolites during the biological treatment of the wastewater effluents. There have been no previous reports giving similar or contrary results. Most of the previous studies have reported effects of single combined sludge.     

Influence of hydraulic retention time in a two-phase upflow anaerobic sludge blanket reactor treating textile dyeing effluent using sago effluent as the co-substrate

Purpose  

Textile dyeing and sago industries are the most polluting industries in South India, especially in industrial cities like Salem, Tamil Nadu, where textile dyeing and sago industries are clumped together geographically. Conventional physicochemical treatment followed by biological processes for the effluent generated from these industries are ineffective, costlier and produce huge quantities of hazardous sludge and harmful by-products which requires further treatment and safe disposal. Hence, the development of an alternative treatment method will become important. The main objective of this investigation is to establish a sustainable biotreatment technology for the treatment of textile dyeing effluent using sago effluent as co-substrate in a two-phase upflow anaerobic sludge blanket (UASB) reactor.     

Coal fly ash as adsorptive material for treatment of a real textile effluent: operating parameters and treatment efficiency

The experimental results performed after the application of one single-stage treatment by sorption onto coal fly ash are evaluated in order to decolorize a real textile effluent of a private company specializing in manufacturing of cotton fabrics (i.e., sorption performance applied for a real textile effluent collected after the fabric dyeing, rinsing, and final finishing steps). The experiments are focused on studying the effect of initial textile effluent pH, adsorbent dose, temperature and adsorption time, considered as operating parameters of sorption process for high pollutant removals (e.g., organic pollutants as dyes, phenols, polymeric, and degradation compounds), and decoloration. The results indicate high values of decoloration degree (55.42–83.00 %) and COD removal (44.44–61.11 %) when it is worked at pH ≤2 with coal ash dose of 12–40 g/L, temperature higher than 20–25 °C, and continuous static operating regime (with an initial agitation step of 3–5 min). The treated textile effluent fulfills the quality demand, and is recyclable, inside reused or discharged after a stage of neutralization (standard pH of 6.5–8.5 for all textile effluent discharges). Also, the final effluent is able to follow the common path to the central biological treatment plant (i.e., a centralized treatment plant for all companies acting in the industrial site area with mechanical–biological steps for wastewater treatment) or may be directly discharged in the nearly watercourse.     

Comparison of dissolved-organic-carbon residuals from air- and pure-oxygen-activated-sludge sequencing-batch reactors.

Literature shows that full-scale pure-oxygen activated sludge (O2-AS) wastewater treatment plants (WWTPs) generate effluents with higher dissolved-organic carbon (DOC) concentrations and larger high-molecular-weight fractions compared to air-activated-sludge (Air-AS) WWTP effluents. The purpose of this paper was to evaluate how gas supplied (air vs. pure oxygen) to sequencing-batch reactors affected DOC transformations. The main conclusions of this paper are (a) O2-AS effluent DOC is more refractory than air-AS effluent DOC; and (b) O2-AS systems may have higher five-day biochemical oxygen demand removals than air-AS systems; however, in terms of COD and DOC removal, air-AS systems are better than O2-AS systems. Analysis of a database from side-by-side O2- and air-AS pilot tests from literature supported these observations.     

Aerobic inhibition assessment for anaerobic treatment effluent of antibiotic production wastewater

Biological treatment of antibiotic production effluents is an economical approach; however, there are still difficulties to overcome because of the recalcitrant characteristics of these compounds to biodegradation. This study aims to reveal that anaerobic treatment technology can be an option as pretreatment before the activated sludge system treatment to treat antibiotic production effluents. The ISO 8192 method was chosen to test the inhibitory effect of raw and treated antibiotic production effluents in this work. Inhibition tests, which were applied according to ISO 8192, highlighted that the anaerobic treatment effluent is less inhibitory than antibiotic production effluent for activated sludge system. Early EC₅₀ concentrations (30-min values) of raw and treated wastewaters were lower than 180-min values. Also, triple effects (sulfamethoxazole–erythromycin–tetracycline) of antibiotics are more toxic than dual effects (sulfamethoxazole–tetracycline). In light of the experimental results obtained and their evaluation, it can be concluded that anaerobic digestion can be applied as a biological pretreatment method for pharmaceutical industry wastewater including antibiotic mixtures prior to aerobic treatment.     

Production of sludge-incorporated paver blocks for efficient waste management

Waste management plays a vital role in the reuse of industry wastes in to useful conversions. The treatment of effluents from the combined textile effluent treatment plant and hypo sludge from the paper industry results in sludge generation, which poses a huge challenge for its disposal. Therefore, an eco-friendly attempt is made to utilize them in the production of paver blocks. Paver blocks are construction units that have vast applications in street roads, walking paths, fuel stations, and so on. In this study, an innovative attempt has been made to manufacture paver blocks incorporating textile effluent treatment plant sludge and hypo sludge, to utilize them in suitable proportions. The effect of adding silica fume and polypropylene fibre in paver blocks has also been studied. Paver blocks containing sludge with different proportions were cast based on the recommendations in Indian Standards (IS) 15658, and the test results were compared with the nominal M20 grade and M30 grade paver blocks. The outcomes of the paver block combinations were studied and found to be an effective utilization of sludge with substantial cement replacement of up to 35%, resulting in effective waste management for specific industries.

Implications: Presently, paver blocks are construction units that have vast application in street roads and other constructions like walking paths, fuel stations, and so on. Also, paver blocks possess easy maintenance during breakages. Based on this application, an innovative attempt has been made to manufacture paver blocks incorporating textile effluent treatment plant sludge and hypo sludge to utilize them in suitable proportions.     

铁盐和铝盐混凝对印染废水生化出水中溶解性有机污染物的去除特性

以三氯化铁和硫酸铝为混凝剂,印染废水二级生化出水为研究对象,并利用XAD-8/XAD-4吸附树脂联用技术将印染废水生化出水中溶解性有机物分为疏水酸、非酸疏水物质、弱疏水物质及亲水物质4类有机物,通过小试实验探讨了2种混凝剂对生化出水中各类溶解性有机物的去除效果及特点。实验结果表明,对于该印染废水的生化出水,溶解性有机物的主要成分是疏水性物质,以DOC表征时占总DOC的75%,其中疏水酸约占41%,疏水性物质也是引起色度的主要物质,所占比例以ADMI7.6表征时为89%,其中以非酸疏水物质的贡献最大,达到52%,并且非酸疏水物质中不饱和双键或芳香环有机物的含量较高。在三氯化铁和硫酸铝各自最佳的混凝条件下,均能够有效去除由疏水性物质（疏水酸和非酸疏水物质）引起的色度,但三氯化铁对弱疏水性物质以及亲水物质的去除率高于硫酸铝,这使得三氯化铁对印染废水生化出水中的溶解性有机物的去除效果优于硫酸铝。并且三氯化铁和硫酸铝混凝工艺均能明显降低生化出水的毒性。     

Regulating colored textile wastewater by 3/31 wavelength ADMI methods in Taiwan

The wastewater from textile dyeing facilities is difficult to treat satisfactorily because of high compositional variability and high color intensity. To reduce colored effluents discharged into watercourses, the government of Taiwan adopted the Effluent True Color Standard in 1998. The true color discharge limit is 400 American Dye Manufactures Institute (ADMI) units. The adopted analytical method is the ADMI Tristimulus Filter Method (3 wavelength (WL) method), and the 31 WL ADMI method might be also adopted as an alternative for color value measurement. The refractory nature of textile dyes and the introduction of this new regulation present an environmental challenge to the Taiwanese textile industry. The main objectives of this study were to (1) evaluate the efficacy of current wastewater treatment systems for controlling the colored textile wastewater discharges, and (2) evaluate the correlations between 3 and 31 WL ADMI methods. Ten representative textile wastewater treatment facilities employing biological and chemical coagulation treatment technologies were selected to perform a 10-consecutive-day effluent sampling and analysis. Results show that a significant difference between 3 and 31 ADMI methods was observed. These two ADMI methods cannot be substituted for each other, and the discharge standard should be determined based on the selected testing method. Investigation results also suggest that the commonly used wastewater treatment technology (biological + chemical coagulation) fails to effectively remove dye from the colored textile wastewater. Sodium hypochlorite (NaOCl) addition was applied by most facilities as the temporary post-polishment step to comply with the color discharge standard.     

Sources of adsorbable organic halogens (AOX) in sludge of Gaza

Average concentrations of adsorbable organic halogens (AOX) in sludge from the Gaza Strip reached 600 mg kg(-1) which currently represents a major limiting factor for sludge application in agriculture. This study aims to identify the main sources of AOX in Gaza where the area is small with limited industrial activities. The results showed that the AOX in effluent sludge is formed mainly inside the treatment plant. Although the plant receives AOX wastewater of only 85 microg l(-1), this value increased five fold inside the plant to an average of 400 microg l(-1) in the effluent wastewater. On the other hand, the sludge from the first sedimentation pond showed an AOX concentration of 213 mg kg(-1) and increased in the final sedimentation pond to 500 mg kg(-1). The AOX concentration in three month old sludge was 130 mg kg(-1). The textile and detergent industries are the major AOX producing industries in Gaza, with an average AOX of 40,000 microg l(-1) in their effluent wastewater. These values do not represent a significant AOX pollution load to the treatment plant because these industries are very limited and their effluents are diluted before entering the municipal treatment plant. Industrial activity decreased in 2006 to less than 70% of the previous four years. Consequently, the AOX in the industrial effluent decreased from 150,000 to 40,000 microg l(-1) over the same time period. Sludge from these industries showed 1300 mg kg(-1) AOX for the past four years and only 400 mg kg(-1) in 2006. Moreover, the AOX in the influent wastewater discharged to the treatment plant decreased from 320 to 85 microg l(-1) for the same period. This study revealed that the major AOX is formed inside the treatment plant and especially in the anaerobic facilities. There was no correlation between the AOX concentrations in the sludge and the wastewater at the same location. Moreover, there was no correlation between the AOX in sludge/wastewater and dissolved oxygen, pH and chloride in that treatment plant.     

Occurrence and fate of heavy metals in the wastewater treatment process

The occurrence and the fate of heavy metals (Cd, Pb, Mn, Cu, Zn, Fe and Ni) during the wastewater treatment process were investigated in the wastewater treatment plant (WTP) of the city of Thessaloniki, northern Greece, operating in the activated sludge mode. For this purpose, wastewater and sludge samples were collected from six different points of the plant, namely, the influent (raw wastewater, RW), the effluent of the primary sedimentation tank (primary sedimentation effluent, PSE), the effluent of the secondary sedimentation tank (secondary sedimentation effluent, SSE), sludge from the primary sedimentation tank (primary sludge, PS), activated sludge from the recirculation stream (activated sludge, AS), and the digested/dewatered sludge (final sludge, FS).

The distribution of metals between the aqueous and the solid phase of wastewater was investigated. Good exponential correlation was found between the metal partition coefficient, logK_p, and the suspended solids concentration. The mass balance of heavy metals in the primary, secondary and the whole treatment process showed good closures for all metal species. The relative distribution of individual heavy metals in the treated effluent and the sludge streams indicated that Mn and Cu are primarily (>70%) accumulated in the sludge, while 47–63% of Cd, Cr, Pb, Fe, Ni and Zn remain in the treated effluent.     

工业废水污泥的热解及升温速率对热解的影响

利用热重分析法对印染、中药和废水处理厂3种典型工业废水污泥进行了热解动力学实验研究。结果表明,工业污泥是一种高挥发分、低固定碳和低热值的劣质燃料。经过消化处理的污泥灰分含量较高,挥发分含量变小。热解过程中有3个失重速率较高的阶段,以挥发分的析出为主。升温速率对热解的最终失重率有重要影响。升温速率增加,热解更剧烈,但最终失重率的变化趋势与污泥种类有关;为使热解效果更好,不同种类的污泥应选择不同的升温速率。不同种类的污泥具有不同的热解特性,印染污泥挥发分析出阶段有2次热解。中药污泥活化能最小,印染污泥挥发分第2次热解的活化能比第1次大幅增加。     

实际污水与模拟污水活性污泥系统的特性差异

实验中经常采用人工配置的模拟生活污水,为了研究其与实际生活污水活性污泥系统的特性差异,采用2个序批式间歇反应器(SBR)进行平行实验(厌氧、好氧方式运行),系统地考察了在进水主要组分和运行参数相同的情况下,不同原水对活性污泥系统脱氮、除磷、比好氧速率、污泥絮体形态和出水水质等方面的影响。结果表明,模拟污水系统的硝化活性强于实际污水系统,两者的平均硝化速率分别为7.43 mg NH4+-N/(L.h)和5.55 mg NH4+-N/(L.h)。在前置厌氧段,模拟污水系统的释磷量比实际污水系统高出36.45%。两者在后续好氧阶段都能够充分吸磷。模拟污水系统的平均比好氧速率(SOUR)高达64.54 mg O2/(g MLSS.h),而实际污水系统的则只有32.81 mg O2/(g MLSS.h)。模拟污水系统的污泥絮体疏松,粒径小,形状不规则,沉降性差,沉后出水平均悬浮物浓度(SS)为20 mg/L;而实际污水系统的污泥絮体则密实、粒径大,沉降性好,沉后水十分清澈,SS几乎检测不出。     

Treatment of textile dyeing wastewater by biomass of Lactobacillus: Lactobacillus 12 and Lactobacillus rhamnosus

The main purpose of this study was to investigate the effectiveness of Lactobacillus 12 and Lactobacillus rhamnosus as both cells and biomasses for the removal of dye from real textile dyeing wastewater. The removal experiments were conducted according to the Box–Behnken experimental design, and the regression equations for the removal of dye were determined by the Minitab 14 program. The optimum variables were found to be 10 g/?L biomass concentration for biomasses, 3 for initial pH of the solution, and 20 °C for temperature with an observed dye removal efficiency of about 60 and 80 % with L. 12 and L. rhamnosus biomasses, respectively. Scanning electron microscopy and Fourier transform infrared spectroscopy images also showed that the biomass characteristics studied were favored by the sorption of the dye from the textile industry wastewater. Consequently, these biomasses may be considered as good biosorbents due to their effective yields and the lower cost of the removal of dyes from the effluents of the textile dyeing house.     

Endocrine disruptors compounds, pharmaceuticals and personal care products in urban wastewater: implications for agricultural reuse and their removal by adsorption process

In the last years, a lot of emerging contaminants, such as, endocrine disruptors compounds (EDCs), pharmaceuticals, and personal care products (PPCPs) have been detected in wastewater. Because of their toxicity and possible adverse effects on the environment and humans, their release from urban wastewater treatment plants (UWWTPs) effluents should be minimized, particularly when a wastewater reuse for crops irrigation is expected. Many processes have been investigated for advanced treatment of UWWTP effluents as well as for emerging contaminant degradation; among these, adsorption process was successfully used to remove EDCs and PPCPs from wastewater. This article shortly reviews EDCs and PPCPs removal from UWWTP effluents by adsorption process using conventional and non-conventional adsorbents. The fate of EDCs and PPCPs in UWWTPs and the implications for agricultural wastewater reuse has been addressed too. In spite of the adsorption process looking to be a valuable alternative to other advanced technologies for the removal of emerging contaminants from wastewater, some gaps still remain to evaluate the actual feasibility at full scale. However, according to a few studies available in scientific literature on the use of both powdered activated carbon and granular activated carbon at full scale, adsorption process by activated carbon is a promising, potentially effective, and economically feasible solution for producing safe wastewater for agricultural reuse.     

微波法制备污泥活性炭研究

采用微波加热法,以污水厂剩余污泥为原料,磷酸为污泥活化剂制备污泥活性炭.微波功率、辐照时间和磷酸浓度对污泥活性炭吸附性能具有显著影响,在最佳工艺条件微波功率480 W、辐照时间315 s和磷酸浓度40%条件下制得的活性炭碘值301 mg/g,比表面积168 m2/g,污泥中重金属绝大部分被固化.与传统商品炭相比,污泥炭孔隙结构以中孔为主.利用该活性炭处理城市生活污水处理厂出水,COD去除率可达87%以上,污泥炭的吸附等温线用Langmuir等温吸附模型进行描述.     

Biodegradability oriented treatability studies on high strength segregated wastewater of a woolen textile dyeing plant

Textile dyeing and finishing industry involves considerable amount of water usage as well as polluted and highly colored wastewater discharges. Biological treatability by means of mineralization, nitrification and denitrification of high strength woolen textile dye bathes, first- and second-rinses is presented. COD fractionation study was carried out and kinetic parameters were determined. Biodegradability of organic compounds in highly loaded composite wastewater after segregation and the effluent of applied biological treatment of high strength composite wastewater were measured by determining oxygen consumption rates. The results were used in terms of assessing an alternative method for inert COD fractionation. The study implied that about 80% soluble COD, 50% color and 75% toxicity reduction were possible by single sludge biological processes. Sixteen per cent of total COD was found to be initially inert. Inert fraction was increased to 22% by production of soluble and particulate microbial products through biological treatment.     

The occurrence of illicit and therapeutic pharmaceuticals in wastewater effluent and surface waters in Nebraska

The occurrence and estimated concentration of twenty illicit and therapeutic pharmaceuticals and metabolites in surface waters influenced by wastewater treatment plant (WWTP) discharge and in wastewater effluents in Nebraska were determined using Polar Organic Chemical Integrative Samplers (POCIS). Samplers were installed in rivers upstream and downstream of treated WWTP discharge at four sites and in a discharge canal at a fifth location. Based on differences in estimated concentrations determined from pharmaceuticals recovered from POCIS, WWTP effluent was found to be a significant source of pharmaceutical loading to the receiving waters. Effluents from WWTPs with trickling filters or trickling filters in parallel with activated sludge resulted in the highest observed in-stream pharmaceutical concentrations. Azithromycin, caffeine, 1,7-dimethylzanthine, carbamazepine, cotinine, DEET, diphenhydramine, and sulfamethazine were detected at all locations. Methamphetamine, an illicit pharmaceutical, was detected at all but one of the sampling locations, representing only the second report of methamphetamine detected in WWTP effluent and in streams impacted by WWTP effluent.