Raw Effluent Research Articles

Sonophotocatalytic treatment of methyl orange dye and real textile effluent using synthesised nano‐zinc oxide

In this work, experiments were carried out by combining the sonication technique with the photocatalytic technique (ultraviolet light source) for the degradation of methyl orange dye and real textile effluent. Studies were performed with variation in parameters such as oxidant (sodium persulfate), commercially available zinc oxide, methyl orange concentration, and sonochemically synthesised zinc oxide. Fourier transform infrared spectroscopy, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and X‐ray diffraction analysis of synthesised zinc oxide showed that the particle size was in the nano range. Near‐complete colour removal by sonophotocatalytic treatment was observed for a concentration of 10 mg l−1 of methyl orange with 1 g l−1 of synthesised zinc oxide and 1500 mg l−1 of sodium persulfate. For 100 mg l−1 of methyl orange, the colour removal was 77% for 1 g l−1 commercially available zinc oxide and 84% for 1 g l−1 synthesised zinc oxide respectively, with 1500 mg l−1 sodium persulfate. Similar experimental conditions were applied for the sonophotocatalytic treatment of real textile effluent with different dilutions (1:100, 1:10, and 1:1) and raw effluent. For real textile effluent, sonophotocatalytic treatment was found to be highly effective both in colour and chemical oxygen demand removal. The chemical oxygen demand removal was 88, 65, 63, and 41% for 1:100, 1:10, and 1:1 dilutions and raw effluent respectively.

Comparative biochemical methane potential of paragrass using an unacclimated and an acclimated microbial consortium

The effect of inoculum sources on the anaerobic digestion of paragrass was investigated. Two types of sludge were used as the inoculums: an anaerobic sludge obtained from a domestic wastewater treatment plant (OS) and a sludge acclimated to fibrous substrates in raw palm oil mill effluent (AMC). Microbial activity assays showed that the AMC had hydrolytic and acetogenic activities two times greater than the activities of the OS. In addition, the production of methane from acetate by the AMC occurred without a lag phase, while it took 8days for the OS to start producing methane from the same substrate. The biochemical methane potential after 80days digestion was 316ml STP/g VSadded using the AMC, and 277ml STP/g VSadded using the OS. The methane potential of the paragrass was estimated to be 3337Nm3 CH4/haa.

Composition of Fungal Flora in Raw Refinery Effluent, Effluent Retention Pond and a Treated Effluent Recipient River

Investigations were carried out to determine the composition of fungal flora in the studied sites. Samples of the raw effluent were collected along the flow channel and the retention pond. Water samples were also collected at the discharge point and up and down stream of the river from the discharge point. The samples were spinned at a speed of 250rpm for 10minutes and spread inoculated the deposits on potato carrot agar (PCA) and potato agar supplemented with 7.5% Nacl. Inoculated plates were incubated aerobically at room temperature in dark cupboard for 7days. Fungal colonies that emerged on the primary culture plates were distinguished into types. The pure isolates were characterized into genera using standard taxonomic guides. Genera such as Aspergillus, Penicillium, Curvularia, Fusarium, Microsporum, Trichoderma, Rhizoctonia, Nigrospora and Chaetophoma species were detected in the raw effluent. However, Microsporum, Trichoderma, Rhizoctonia, Nigrospora and Chaetophoma species were conspicuously absent in the effluent retention pond. Only Trichoderma and Chaetophoma species were absent in water samples collected at the treated effluent discharge point into the recipient River. Samples of water collected up stream of the discharge point did not contain Geotrichum, Nigrospora and Chaetophoma species. Curvularia, Microsporum, Rhizoctonia and Nigrospora species were not detected in water samples collected downstream of the discharge point. It was therefore concluded that, fungi constitute a significant proportion of the microflora of sites contaminated with the refinery effluent and could be playing an important role in the remediation of sites receiving the effluent. © JASEM Keywords : Fungal flora, Refinery effluent, Retention ponds, Discharge point, Upstream, Downstream

Resistance to some Heavy Metals among Fungal Flora of Raw Refinery Effluent

Investigations were carried out to assess the capacity of strains of fungi isolated from raw flowing effluent and effluent retention pond of Kaduna refinery plant to resist and grow in the presence of lead (Pb), nickel (Ni) and cadmium (Cd) invitro. Fungi belonging to the genera including Aspergillus spp., Penicillium spp., Fusarium spp., Curvularia spp. and Nigrospora spp. were isolated from the study sites. The isolates were inoculated into duplicate 100ml flask containing 50ml of potato dextrose broth (PDB) supplemented with 5,10 and 15ppm of Pb, Ni, and Cd. Each test isolate was inoculated into duplicate flask containing the same medium without the heavy metals to serve as control. All inoculated flasks were incubated aerobically at room temperature on a rotator shaker for 7days. The mycelial mats were harvested by filtering the cultures through preweighed filter paper (No.1). The filters bearing the mycelial mats were dried in an oven at 70oC for 18hours. It was observed that most of the isolates tested resisted and grew in the medium containing 5 to 15ppm of tested heavy metals. Yield of dry mycelia mats in the heavy metal supplemented medium were also comparable to those grown in heavy metal free PDB medium. It was concluded that, these genera of fungi could be playing an important role in the removal of these metals usually present in the raw effluent during the period of residency in the retention pond through bioaccumulation. ©JASEMKeywords: Fungal flora, Heavy metals, Resistance, Refinery effluents

The importance of pretreatment tailoring on the performance of ultrafiltration membranes to treat two-phase olive mill wastewater

In this work, the performance of an ultrafiltration (UF) membrane in the treatment of the effluents by-produced by olive mills is addressed by applying different pretreatments on the raw effluents. By conducting a photo-catalytic process (UV/TiO 2 PC) after pH-temperature flocculation (pH-T F) higher threshold flux values were observed for all feed stocks than by applying solely the pH-T F process, with an 18.8–34.2% increment. In addition, the performance of the UF membrane was also improved in terms of rejection efficiency, such that higher rejection values were yielded by the membrane for the organic pollutants (R COD ) by 48.5 vs. 39.9% and 53.4 vs. 42.0%. The UF membrane performance was also improved in terms of the volume feed recovery factor (VFR), achieving up to 88.2 vs. 87.2% and 90.7 vs. 89.3%. Results in the same line were also observed when the highly polluted olives oil washing wastewater raw stream was previously mixed with the effluent stream coming from the washing of the olives. This permits the UF to permeate, achieving the standard limits to reuse the purified effluent for irrigation purposes (COD values below 1000 mg·L −1 ), which makes the treatment process cost-effective and results in making the olive oil production process environmentally friendly.

Integrated synthesis of zeolites 4A and Na–P1 using coal fly ash for application in the formulation of detergents and swine wastewater treatment

Several researchers have reported zeolite synthesis using coal ash for a wide range of applications. However, little attention has been given to green processes, including moderate synthesis conditions, using waste as raw material and effluent reuse or reduction. In this study, Brazilian coal fly ashes were used for integrated synthesis of zeolites 4A and Na–P1 by two different routes and under moderate operating conditions (temperature and pressure). Both procedures produced zeolites with similar conversions (zeolite 4A at 82% purity and zeolite Na–P1 at 57–61%) and high CEC values (zeolites 4A: 4.5meqCa2+g−1 and zeolites Na–P1: 2.6–2.8meqNH4+g−1). However, process 1 generated less effluent for the zeolite mass produced (7mLg−1), with low residual Si and Al levels and 74% of the Si available in the coal fly ash incorporated into the zeolite, while only 55% is used in process 2. For use as a builder in detergents, synthetic zeolite 4A exhibited conformity parameters equal to or greater than those of the commercial zeolite adopted as reference. Treatment of swine wastewater with zeolite Na–P1 resulted in a high removal capacity for total ammoniacal nitrogen (31mgg−1).

Catalytic Ozonation Using Fe2+in the Treatment of Dairy Effluent in a Semi-Batch Process with Recycle

This work describes the treatment of dairy industry effluent using catalytic ozonation with Fe2+ as its catalyst in a semi-batch process with recycle. A fractional factorial design 24-1 was used with a reduction percentage of total organic carbon (TOCred) as response. Optimal conditions were obtained by the reaction time of 30 min, ozonator power of 35 W, O2 flow rate of 0.125 L min-1, Fe2+ concentration of 1.0 g L-1 and pH 4.0 for a 2 L raw effluent. TOCred of 64.03% represents a decrease in concentration from 473.0 to 170.1 mg L-1, with an estimate cost of US$ 0.03 L-1effluent. The treatment performed was not sufficient to discharge it directly on surface water; however, significant reduction of TOCred, among physical and chemical characteristics makes a better product to be proceeded into a biological treatment.

Study on the effect of textile effluent on the growth and fecundity of Eudrilus euginiae

Eudrilus euginiae is one among the well studied species of earthworms involved in the conversion of organic waste resources into value added products (vermicompost). Efforts were taken to understand the impact of textile effluent on the population of earthworms mimicking the condition prevalent in textile belt of Tamil Nadu, India where effluents are drained into the cultivable land through the water stream. Categories of earthworms were maintained and drained with calculated amounts of raw, chemically and biologically treated effluents for a period of eight weeks in which fecundity and growth were recorded. There was significantly high fecundity in the soil treated with raw effluent than that of control and the treated effluents suggesting us to use of these worms for bioremediation of textile effluent polluted soil.

Removal of Organics and Metal Ion Nanoparticles from Synthetic Wastewater by Activated Sludge Process (ASP)

Adsorption technique is widely used for removal of toxic organic contaminants from aqueous streams. Owing to the hazardous or otherwise undesirable characteristics of phenolic compounds in particular, their presence in wastewater from municipal and industrial discharge is one of the most important environmental issue. The discharge of poor quality effluents by the chemical-based laboratories and refineries in India is posing a serious threat to water sources and wastewater treatment installations alike. Our study was set up in the Indo-French Unit for Water and Wastewater Technologies (IFUWWT), IIT Delhi. The main objective of this study was to assess the efficiency of a laboratory-scale activated sludge treatment process in producing a final effluent conforming to regulatory standards of Central Pollution Control Board, India (CPCB norms) with regards to COD and metal ion loads. The study was conducted in three principal stages: characterization of wastewater containing nanoparticles; treatability studies of laboratory generated discards and investigations of heavy metal ions before and after treatment. The various raw effluent parameters analyzed were COD, BOD, F/M ratio, Sludge Value Index, Total Solids and concentrations of Cu, Ag and Zn. Studies were conducted using two aerobic Sequencing Batch Reactors (SBR). MLSS of the aeration basin was calculated to be 7180 ± 261.3 mg/L while the F/M ratio was kept down to 0.1560 ± .0149; besides, an SVI of 107.24 mL/g complied with the state of bioreactor’s sludge. These set of values suggested to set an extended aeration processes for the reactors. Accordingly, the detention time in aeration basin was 24 hours. The results showed over 98% influent COD reduction and nearly 100% removal of metal ions. The sample used was operated on sludge collected from Vasant Kunj Wastewater Treatment plant. Based on the results from waste characterization and treatability studies, it was decided that the mixed liquor discharged in the activation tank should have glucose solution and laboratory discarded sample in 1:1 ratio. The reactor was operated on a glucose fed batch basis for 30 days. For the sake of metal analysis, the digested water samples were analyzed for the presence of copper, silver and zinc using the Element AS AAS4141 atomic adsorption spectrophotometer (by Electronics Corporation of India Ltd). The Biosorption capacities were found to be over 95% in all the cases with the minimum correlation coefficient for calibration curve being 0.9811. Such a high sludge yield is suggestive of the fact that heavy metals are in very low concentrations in the considered carboy sample. Because of these insignificant values, the amount of metal ions introduced to the system gets adsorbed almost completely, hence leaving behind no metal ion within the supernatant. Well-treated wastewater has enormous potential as a source of water for crops, households and industry.

Treatment of Effluent from the Agate Dyeing Industry Using Photodegradation and Electrodialysis Processes

The industrial dyeing of agates employs considerable quantities of synthetic dyes (organic and metallic ions). The aim of the present study was to investigate the potential value of coupling photodegradation with electrodialysis in the degradation of organic dyes and in the removal of contaminant ions present in raw effluent obtained from the agate dyeing industry. Photodegradation was carried out on a pilot-scale in a flow cell reactor fitted with a 400 W lamp. Electrodialysis was performed in a cell comprising three compartments separated by ion-selective membranes and fitted with a 70TiO2/30RuO2 DSA® anode and a titanium plate as cathode. The treatment produced a 62% reduction in the TOC present in the raw effluent, and around 20.5% of total nitrogen was extracted. Thus it was concluded that coupling photochemical degradation with electrodialysis represents an efficient method for treating effluents.

The Integrated System of Phytodepuration of Sile River Natural Park

The water conservation topic is likely to become increasingly important and alternative water resources employment should be considered as one possible response to the challenges of fresh water demand and environmental protection; among alternative water sources, municipal wastewaters represent one of the most profitable source but in order to reuse them they need adequate and advanced depuration techniques, such as the use of Integrated System of Phytodepuration (ISP). Across a 3-year sampling period, the performances of an ISP within the Natural Park of the Sile River in the Northern Italy were evaluated, analyzing raw wastewater and final effluent characteristics according to the recommendations of European and Italian legislation. The investigated ISP represents one of the first attempts designed in Italy to improve the efficiency of an existing wastewater treatment plant, able to serve 8000 equivalent inhabitants. The results obtained during the 3 years of analysis show that the designed ISP is characterized by a general efficiency value higher than 87% for TSS removal, 79% for TN, 91% for BOD5 and 86% for COD; moreover the ISP final effluent is characterized by a quality not only suited for release into surface waters but also for irrigation.

Simultaneous treatment of raw palm oil mill effluent and biodegradation of palm fiber in a high-rate CSTR

A high-rate continuous stirred tank reactor (CSTR) was used to produce biogas from raw palm oil mill effluent (POME) at 55°C at a highest organic loading rate (OLR) of 19g COD/ld. Physical and chemical pretreatments were not performed on the raw POME. In order to promote retention of suspended solids, the CSTR was installed with a deflector at its upper section. The average methane yield was 0.27l/g COD, and the biogas production rate per reactor volume was 6.23l/ld, and the tCOD removal efficiency was 82%. The hydrolysis rate of cellulose, hemicelluloses and lignin was 6.7, 3.0 and 1.9g/d, respectively. The results of denaturing gradient gel electrophoresis (DGGE) suggested that the dominant hydrolytic bacteria responsible for the biodegradation of the palm fiber and residual oil were Clostridium sp., while the dominant methanogens were Methanothermobacter sp.

Comparative study on the treatment of raw and biologically treated textile effluents through submerged nanofiltration

Raw and biologically treated textile effluents were submerged filtrated using lab-fabricated hollow fiber nanofiltration membrane with a molecular weight cut-off of about 650g/mol. Permeate flux, chemical oxygen demand (COD) reduction, color removal, membrane fouling, and cleaning were investigated and compared by varying the trans-membrane pressure (TMP) and volume concentrating factor (VCF). It was found that both raw and biologically treated textile effluents could be efficiently treated through submerged nanofiltration. The increase of TMP resulted in a decline in water permeability, COD reduction, color removal, and flux recovery ratio, while the increase of VCF resulted in both increased COD reduction and color removal. Under the TMP of 0.4bar and VCF of 5.0, fluxes of 1.96 and 2.59l/m2h, COD reductions of 95.7 and 94.2%, color removals of 99.0, and 97.3% and flux recovery ratios of 91.1 and 92.9% could be obtained in filtration of raw and biologically treated effluents, respectively. After filtration, the COD and color contents of the raw effluent declined sharply from 1780 to 325mg/l and 1.200 to 0.060Abs/cm, respectively, while for the biologically treated effluent, they decreased from 780 to 180mg/l and 0.370 to 0.045Abs/cm, respectively.

Technical optimization of an integrated UF/NF pilot plant for conjoint batch treatment of two-phase olives and olive oil washing wastewaters

The membrane plant dimension and fouling control strategy of an integrated batch UF and NF membranes-in-series process is addressed for the simultaneous treatment of the two main effluents generated in olive mills operating with the two-phase technology, in particular wastewater derived from the washing of the olives (OWW) and from the olive oil washing during the vertical centrifugation (OOW). Beforehand, the raw effluent, that is, 1:1v/v mixture of OWW and OOW, called OWMW2, was pretreated by pH–temperature flocculation stand-alone or followed by photocatalysis with TiO2 nanoparticles under UV irradiation. The proposed model is able to predict the permeate flux performance of the selected membranes at a given time as a function of the applied pressure and organic matter load of the feedstock accurately. Moreover, working upon threshold conditions provides significant and stable fluxes, 15.5Lh−1m−2 on the UF membrane and 22.2Lh−1m−2 on the NF one, minor fouling build up (28.6–33.3% reduction) as well as required membrane area, 170.3 and 61m2, respectively. Finally, the treatment line just comprising UF preceded by pH–T flocculation and UV/TiO2 photocatalysis provides an effluent compatible for irrigation and permits the minimum membrane plant dimension (only 6 total modules).

Treatment of Palm Oil Mill Effluent by a Microbial Consortium Developed from Compost Soils.

A method for the aerobic treatment of palm oil mill effluent (POME) was investigated in shake-flask experiments using a consortium developed from POME compost. POME was initially centrifuged at 4,000 g for 15 min and the supernatant was enriched with (NH4)2SO4 (0.5%) and yeast extract (0.25%) to boost its nitrogen content. At optimum pH (pH 4) and temperature (40°C) conditions, the chemical oxygen demand (COD) of the effluent decreased from 10,350 to 1,000 mg/L (90.3%) after 7 days. The total bacterial population determined by plate count enumeration was 2.4 × 106 CFU/mL, while the fungal count was 1.8 × 103 colonies/mL. Bacteria of the genera Pseudomonas, Flavobacterium, Micrococcus, and Bacillus were isolated, while the fungal genera included Aspergillus, Penicillium, Trichoderma, and Mucor. When the isolated species were each inoculated into separate batches of the raw effluent, both pH and COD were unchanged. However, at 75 and 50% POME dilutions, the COD dropped by 52 and 44%, respectively, while the pH increased from 4 to 7.53. POME treatment by aerobic method is sustainable and holds promising prospects for cushioning the environment from the problems associated with the use of anaerobic systems.

Removal of COD from a stabilized landfill leachate by physicochemical and advanced oxidative process

This work investigated the effectiveness of a physicochemical and oxidative process for the removal of chemical oxygen demand (COD) from stabilized landfill leachates. The application of these technologies for landfill leachate treatment greatly depends on the optimal operating conditions for a specific leachate. Coagulation-flocculation followed by H2O2, Fenton and photo-Fenton processes was evaluated. Advanced oxidation processes were evaluated in the raw leachate and the leachate pretreated by coagulation-flocculation. Via the coagulation process, at 30 sec and a stirring speed of 150 rpm followed by flocculation and settling steps, 53% COD was removed at an optimal dose of 1400 mg L−1 and pH 4.0. Moreover, from the POA evaluated, the Fenton process was determined to be the most effective process for removing COD from the leachate pretreated by coagulation-flocculation, reaching 83.3% COD removal with 1330 mg L−1 of H2O2 and 266 mg L−1 of Fe2+. The photo-Fenton process applied directly to the raw effluent was effective for the removal of COD; a 75% reduction in COD was observed in tests using 2720 mg L−1 of H2O2 and 544 mg L−1 of Fe2+. Due to the variability in the composition of the Gramacho landfill leachate, the combination of coagulation-flocculation and the Fenton process is an effective technology for reducing the COD in samples of this leachate.

Treatment and Reuse of Effluents from Palm Oil, Pulp, and Paper Mills as a Combined Substrate by Using Purple Nonsulfur Bacteria

The growth of Rhodobacter sphaeroides NCIMB8253 was investigated under photoanaerobic conditions with different concentrations of palm oil mill effluent in a dual effluent growth medium. The influence of pulp and paper mill effluent as an alternative diluting agent on the bacterial growth was also investigated. During this study, it was determined that the use of pulp and paper mill effluent as a diluting agent promoted bacterial growth compared with the use of raw palm oil mill effluent medium alone. The cell growth data for all experimental sets were well-fitted to the logistic and modified Gompertz models. The results revealed that 25% (v/v) palm oil mill effluent medium with pulp and paper mill effluent as a diluting agent, namely G5 medium, can be applied as a suitable growth medium. A maximum colony-forming-units (CFU) number of 360 × 108 CFU/mL was achieved in G5, which was higher than that for raw palm oil mill effluent and comparable with that for water-diluted palm oil mill effluent medium. Furthermore, chemical oxygen demand level (CODtotal and CODsoluble) reductions were observed in all treatments.

Phytoremediation of Parboiled Rice Mill Wastewater Using Water Lettuce (Pistia Stratiotes)

Phytoremediation is an emerging technology applied for treatment of wastewater. It is a suitable option notably in developing countries as it is simple, sustainable and cost effective. In the present lab-based batch study the free floating aquatic plant water lettuce (Pistia stratiotes) is used for treatment of parboiled rice mill wastewater having low pH, high chemical oxygen demand (COD), nitrogen, and phosphate. In raw rice mill wastewater (undiluted) growth of water lettuce is found to be inhibited. Later on, two different dilution approaches (raw and facultative pond effluent 1:1; raw and tap water 1:1) are applied in order to effectively use this technology. In all cases a control (without plant) is maintained to compare the performance with the Aquatic Plant based Treatment (APT) system. In the APT system results reveal that removal of soluble COD (SCOD), ammoniacal nitrogen (NH4-N), nitrate nitrogen (NO3-N), and soluble phosphorus (sol. P) are upto 65%, 98%, 70%, and 65% respectively. The study highlights the efficacy of water lettuce in removing organics and nutrients from parboiled rice mill wastewater.

Plant-available inorganic nutrient levels are increased in rice-derived distillery effluents inoculated with microbes.

The purpose of this study was to assess the effects of microbes on plant-available inorganic nutrients and a phytohormone in rice-derived distillery effluents. The effects of 37 microbial strains on the components of distillery effluents were investigated. Inoculation of several Aspergillus and Bacillus strains resulted in accumulation of a large quantity of ammonium nitrogen (NH4-N; 774 ± 490 and 1059 ± 463 mg l(-1), respectively) in the effluent. However, a decrease in the liquid phase during Aspergillus incubation suggested the requirement for additional treatment of the solid residue, whereas the growth of Bacillus subtilis was inhibited by the acidic conditions in the raw distillery effluent. Interestingly, Aspergillus caelatus, Aspergillus oryzae and Aspergillus tamarii yielded greater increases in nitrate concentrations (30-39 mg l(-1)). Colorimetric and gas chromatography-mass spectrometry analyses revealed that Wickerhamomyces strains generated 7-26 mg l(-1) of indole-3-acetic acid (IAA) when the effluent pH was adjusted to 7·0. Inoculation of several Aspergillus and Bacillus strains into distillery effluents resulted in the production of a large quantity of NH4-N. This study provides information that will facilitate the bioconversion of distillery effluent into fast-acting liquid fertilizers.

Systematic optimization of an SPE with HPLC-FLD method for fluoroquinolone detection in wastewater

This paper describes a selective and ultra-sensitive analytical method for simultaneous determination of 11 fluoroquinolone (FQ) antibiotics in environmental and wastewater samples. The method employs offline solid-phase extraction (SPE) and reversed-phase high performance liquid chromatography with fluorescence detection (HPLC-FLD). A weak cation exchange SPE protocol was developed with a novel loading volume optimization algorithm and a methanol cleanup step to remove background organic matter. Various parameters were optimized to recover FQs from water/wastewater and analyte recovery was generally greater than 80%. Chromatographic separation of the 11 FQs was achieved on a 150mm pentafluorophenyl column using a gradient elution scheme with methanol, acetonitrile, and 20mM phosphate buffer (pH=2.4). Excitation and emission wavelengths were individually optimized for each FQ using fluorescence spectroscopy; the excitation and emission wavelengths were 276–296nm and 444–506nm, respectively. Instrumental quantitation limits were 20–100pg of mass injected. Of the 11 FQs investigated, seven (i.e., ciprofloxacin, difloxacin, enrofloxacin, fleroxacin, norfloxacin, moxifloxacin, and ofloxacin) were detected during a four-month sampling campaign of wastewater and wastewater-impacted surface water. Concentrations of FQs in raw wastewater, wastewater effluent, and wastewater-impacted surface water were 5–1292, 2–504, and 4–187ng/L, respectively.