Tank Sludge Research Articles

MECHANICAL PROPERTIES OF BIO MINERALIZED CONCRETE

Quantities of sludge from septic tank and quarry rock dust from industries have been on the rise in recent years due to the rapid improvement in the standard of living and the increase in industrialization. Unfortunately, the majority of sludge from septic tank is not being recycled and hence it causes serious problems on natural resources and environment. For these reasons, this study has been conducted through basic experimental research in order to analyze the possibilities of recycling the sludge from septic tank as a supplementary material in cement concrete. In this research various proportions of septic tank sludge and quarry rock dust are used as supplement to sand in cement concrete and also various proportions of bacterial solutions are used as a supplement to water. The works under taken here dealt with the use of quarry rock dust, septic tank sludge and bacterial water as a supplementary material in cement concrete. In this investigation ,% of water absorption and compressive strength criteria were analyzed by introducing septic tank sludge, quarry rock dust and bacterial solution into the cement concrete.

Cultivating and harvesting of marine alga Nannochloropsis oculata in local municipal wastewater for biodiesel

The feasibility of using the mixture of seawater and municipal wastewater; (1) the wastewater before activated sludge tank, just after primary settling (BAS) and (2) the wastewater after activated sludge tank, just before addition of polymer flocculants (AAS); as culture medium for the cultivation of marine microalgae Nannochloropsis oculata was investigated.10% BAS, 20% BAS and 10% AAS, 20% AAS, 50% AAS, 70% AAS, 100% AAS effluent loadings were well adapted to used wastewater. Sufficient dry weights obtained (345–406mgL−1) with growth rates 0.37–0.45 for aerated cultures. High TN and TP removals (∼74–90%) were achieved. Harvesting technique for grown cultures was also studied with natural sedimentation and pH induced flocculation. By alkalinity induced flocculation, at pH values of 10.50, high recovery of the cells (∼80%) achieved with high sedimentation rates in 10min. The flocculation efficiencies decreased, sedimentation rates increased with the increase of the cell concentration.

The characteristics of sludge from enhanced coagulation processes using PAC/PDMDAAC composite coagulants in treatment of micro-polluted raw water

The characteristics and dewatering performance of sludge in sedimentation tanks, produced by enhanced coagulation process using composite coagulants were systemically studied in the treatment of micro-polluted raw water. Two processes, the conventional coagulation process using PAC and the enhanced coagulation process using PAC/PDMDAAC composite coagulants, were parallelly operated in 2 pilot-plants for each with production capability of 4m3/h potable water. Then the volume, solid content, zeta potential and dewatering ability of the sludge from the two processes were compared. The results showed that the volume of sludge produced from enhanced coagulation process using composite coagulants was 30.06–38.63% less than that of using PAC, and then the discharge interval of sludge from using composite coagulants was 41.78–63.28% longer than that of using PAC. Besides, the sludge from the enhanced coagulation process using composite coagulant displayed a more compact structure, higher solid content and higher zeta potential values than that from conventional coagulation process using PAC, and the water content of filter cakes after vacuum filtration of the sludge could achieve to 80%, indicating an obvious feature of its dewatering ability directly. The reasons for the compact structure and low volume of the sludge might be the strong enhancement in the charge neutralization and bridge ability of PAC by composing PDMDAAC in the composite coagulants.

Performance of a system with full- and pilot-scale sludge drying reed bed units treating septic tank sludge in Brazil.

This study investigated the performance of sludge drying reed beds (SDRB) at full- and pilot-scale treating sludge from septic tanks in the city of Belo Horizonte, Brazil. The treatment units, planted with Cynodon spp., were based on an adaptation of the first-stage of the French vertical-flow constructed wetland, originally developed for treating sewage. Two different operational phases were investigated; in the first one, the full-scale unit was used together with six pilot-scale columns in order to test different feeding strategies. For the second phase, only the full-scale unit was used, including a recirculation of the filtered effluent (percolate) to one of the units of the French vertical wetland. Sludge application was done once a week emptying a full truck, during 25 weeks. The sludge was predominantly diluted, leading to low solids loading rates (median values of 18 kgTS m(-2) year(-1)). Chemical oxygen demand removal efficiency in the full-scale unit was reasonable (median of 71%), but the total solids removal was only moderate (median of 44%) in the full-scale unit without recirculation. Recirculation did not bring substantial improvements in the overall performance. The other loading conditions implemented in the pilot columns also did not show statistically different performances.

Reproduction of Staurastrum sp. within a water treatment plant caused by the recycle of combined sludge water and backwash water: a field investigation

It is well known that the recycle of sludge water and filter backwash water in drinking water treatment plants (WTP) may cause water quality problems including suspended solids, pathogenic protozoans, dissolved organic matters, and disinfection by-products. However, it is still uncertain whether the recycle process can cause algal problems in a WTP with algal-laden raw water. A field survey was performed in a WTP, located in Tianjin, China, to investigate the variation of algal species and density during the treatment and recycle process. The results showed Staurastrum sp., a non-dominant species in raw water, regrew and became the unique dominant species in the combined sludge tank (CST). The reproduction of Staurastrum sp. increased the treatment loading, clogged the filter, and deteriorated the quality of finished water. Bench-scale experiments indicated chlorination was inefficient to inactive Staurastrum sp., which resulted in that living cells of this alga can enter into the CST. Culture experiments indicated Staurastrum sp. favors a moderate concentration of Fe (0.6–2.0 mg/L) and grows slowly under a low concentration (0.1 mg/L). Thus, the high concentration of Fe (0.6 mg/L) originated from the residual coagulant facilitated the reproduction of this alga in the CST. Cutting off the recycle pathway and destroying the favorable growing conditions in the CST may be feasible methods to control the reproduction of Staurastrum sp. in the WTP. This study showed the recycle of sludge water and filter backwash water can cause algal problems in WTPs, which should be an important issue for drinking water treatment researchers and engineers.

Evaluation of the sludge reduction effectiveness of a metabolic uncoupler-tetrakis (hydroxymethyl) phosphonium sulfate in anaerobic/anoxic/oxic process

A metabolic uncoupler, tetrakis (hydroxymethyl) phosphonium sulfate (THPS), was used to reduce sludge production in a laboratory-scale anaerobic/anoxic/oxic (A2/O) process. THPS was continuously added into anaerobic, anoxic, and oxic tank of the systems, respectively, along with 3.5 mg/L influent. The effects of THPS additions on sludge reduction, wastewater treatment efficiencies, and sludge characteristics were discussed in about a 99 d operational period. The results showed that the cumulative reduction of waste activated sludge reached about 30.8–31.7% and the decrease of sludge yield (Yobs) reached about 16.1–16.5% with the system added THPS in the anaerobic tank the most. Meanwhile, the wastewater treatment efficiency decreased slightly when THPS was added. Analysis of microbial communities in activated sludge in the oxic tank suggested that adding THPS would result in a new dominant micro-organism. However, the efficiencies of sludge reduction and wastewater treatment and microbial communities of activated sludge were similar when THPS was added into different tanks of the A2/O process, so the adding site of the metabolic uncoupler had little effect.

High Quality Oil Recovery from Oil Sludge Employing a Pyrolysis Process with Oil Sludge Ash Catalyst

In this study, pyrolysis experiments of two kinds of oil sludge were conducted using a bench-scale fixed bed reactor, which is mainly consisted of a pyrolyzer and a reformer reactor. The effects of the pyrolysis method and the catalysts on the yield and quality of oil products obtained from pyrolysis of oil sludge were investigated. Characterization of the oil products was preliminary judged by comparing their distillation results with the diesel standard and the oil product without catalyst usage. Then, the chemical characterization of a part of the pyrolytic oil was conducted by FT-IR and NMR analysis. In the last step of these experiments, the oil products obtained from pyrolysis of oil sludge with the use of oil field sludge ash and oil tank sludge ash as catalysts were mixed with diesel oil by the volume ratio of one-to-five and one-to-ten. The fuel characteristic of the oil mixtures was identified from the point of the viscosity, the density, the cetane index, the carbon number distribution and the higher heating value (HHV). The results of experiment show that the highest oil product yield was obtained at the one-stage pyrolysis of the oil field sludge and also the oil tank sludge with the oil field sludge ash as the catalyst. According to the results of NMR analysis, the main part of the carbon in the oil product from pyrolysis of the oil sludge with the oil sludge ash was aliphatic carbon. The total ring number of oil products decreased owing to the hydrogenation and ring-open of naphthenic hydrocarbon during the catalytic pyrolysis process. The highest HHV and the cetane index could be obtained when the oil product from the one-stage pyrolysis process of the oil field sludge with the oil field sludge ash was mixed with diesel by the mixing ratio of 1: 10. The results of this study are of practical interest and will help to lead the researchers to more thinking about the oil recovery from oil sludge.

福岡県大木町における生ごみ・し尿・浄化槽汚泥資源化の多面的効果に関する研究

福岡県大木町における生ごみ・し尿・浄化槽汚泥資源化の多面的効果に関する研究

Enhanced sludge reduction in septic tanks by increasing temperature

Septic tanks in most developing countries are constructed without drainage trenches or leaching fields to treat toilet wastewater and /or grey water. Due to the short hydraulic retention time, effluents of these septic tanks are still highly polluted, and there is usually high accumulation of septic tank sludge or septage containing high levels of organics and pathogens that requires frequent desludging and subsequent treatment. This study aimed to reduce sludge accumulation in septic tanks by increasing temperatures of the septic tank content. An experimental study employing two laboratory-scale septic tanks fed with diluted septage and operating at temperatures of 40 and 30°C was conducted. At steady-state conditions, there were more methanogenic activities occurring in the sludge layer of the septic tank operating at the temperature of 40°C, resulting in less total volatile solids (TVS) or sludge accumulation and more methane (CH4) production than in the unit operating at 30°C. Molecular analysis found more abundance and diversity of methanogenic microorganisms in the septic tank sludge operating at 40°C than at 30°C. The reduced TVS accumulation in the 40°C septic tank would lengthen the period of septage removal, resulting in a cost-saving in desluging and septage treatment. Cost-benefit analysis of increasing temperatures in septic tanks was discussed.

INTRODUCTION OF AN IMPROVED JET HYDRAULIC MIXER FOR MAINTAINING FIRE SAFETY AND EFFECTIVE WORK TANK FARM

As a result of the development, testing and implementation of improved hydraulic jet mixer in the oil and gas industry of the Republic of Bashkortostan and Tatarstan identified following its advantages over electromechanical stirrers. 1. Submission to the oil reservoir through the mixer leads to its homogenization by volume, which is a prerequisite for efficient refining-ing of such oil at the refinery due to the stabilization of its properties over time. 2. Reduces the amount of oil during transportation due to lack of sediment sludge in tanks. The composition of sludge consists mainly of paraffinic hydrocarbons of normal structure and asphaltenes. 3. There is no need periodic cleaning of tanks from sludge-proposals, leading to the conclusion of their operation; in the transport and disposal of sludge, for example, by burning it. Services are paid for burning. 4. Operation of the mixer does not cause deterioration in the terms of industrial safety in the tank farm and is not associated with the consumption of additional electricity. 5. After the mixer does not cause vibration of the walls of the tank and hence its premature failure. 6. The mixer can be installed on any flow performance. 7. The mixer works effectively on tanks of any capacity.

BMP실험을 이용한 음식물폐기물 및 분뇨의 병합소화 특성

분뇨/정화조슬러지와 음식물폐기물의 병합소화 특성을 확인하기 위하여 BMP 테스트를 실시하였다. 생슬러지, 잉여슬러지, 소화슬러지, 분뇨/정화조슬러지(1:1의 비율로 조성), 음식물폐기물(음식물 파쇄물과 희석수의 비=1:1) 및 혼합슬러지의 6개의 슬러지를 대상으로 30일간 실험을 진행하였다. 바이오가스 발생은 초기 2일 이후부터 활발히 시작되어 2주 동안 지속되는 것을 알 수 있었으며 일정 시간이 경과한 후에는 발생량이 급격히 감소하는 것을 확인하였다. 특히 7~8일 사이에 가스발생량이 최대값을 보였으며, Modified Gompertz model을 이용한 생슬러지, 잉여슬러지, 소화슬러지, 분뇨/정화조슬러지, 음식물폐기물 및 혼합슬러지의 단위메탄생산량은 각각 64.63, 67.49, 66.45, 72.44, 107.85, 46.71 mL <TEX>$CH_4/g$</TEX> VS로 나타났다. 혼합슬러지의 지체성장기간은 1.88 day이었으며, 최대메탄생산속도는 80.4 mL/day로 나타났다. 따라서 메탄생성퍼텐셜을 높이기 위해서는 하수처리장의 혐기성 소화조에 투입되는 음식물폐기물의 혼합비를 조절함으로써 빈부하 문제 해결과 동시에 소화조의 안정적인 운전을 기대할 수 있을 것으로 사료된다. BMP test was carried out to evaluate the characteristics for co-digestion of night soil and food waste. 6 types of sludge were tested in 30 days which were raw, excess, digested, night soil/septic tank (1:1), food waste (food : dilution water = 1:1), and mixed sludge. Bio gas was produced actively after 2 days, and continued in 2 weeks. Gas generation amount was decreased rapidly after considerable space of time. Especially maximum productivity of gas was shown in 7~8 days. The ultimate methane yields of raw, excess, digested, night soil/septic tank, food waste, and mixed sludge were 64.63, 67.49, 66.45, 72.44, 107.85, and 46.71 mL <TEX>$CH_4/g$</TEX> VS respectively from Modified Gompertz model. The lag growth phase time and maximum specific methane production rate of mixed sludge were 1.88 day and 80.4 mL/day respectively. The methane potential of mixed sludge was higher than individual sludge. So high methane potential was expected by controlling mixing ratio of food waste. Besides stable operation of digestion tank and the solution of oligotrophic problem were possible.

The influence of additives on rheological properties of limestone slurry

Limestone slurry appears in the lime production process as the result of rinsing the processed material. It consists of particles with diameter smaller than 2 mm and the water that is a carrier of solid fraction. Slurry is directed to the settling tank, where the solid phase sediments and the excess water through the transfer system is recovered for re-circulation. Collected at the bottom of the tank sludge is deposited in a landfill located on the premises. Rheological properties of limestone slurry hinder its further free transport in the pipeline due to generated flow resistance. To improve this state of affairs, chemical treatment of drilling fluid, could be applied, of which the main task is to give the slurry properties suitable for the conditions encountered in hydrotransport. This treatment consists of applying chemical additives to slurry in sufficient quantity. Such additives are called as deflocculants or thinners or dispersants, and are chemical compounds which added to aqueous solution are intended to push away suspended particles from each other.The paper presents the results of research allowing reduction of shear stress in limestone slurry. Results demonstrate rheological properties of limestone slurry with and without the addition of modified substances which causes decrease of slurry viscosity, and as a consequence slurry shear stress for adopted shear rate. Achieving the desired effects increases the degree of dispersion of the solid phase suspended in the carrier liquid and improving its ability to smooth flow with decreased friction.

Effect of process design and operating parameters on aerobic methane oxidation in municipal WWTPs

Methane is a potent greenhouse gas and its emission from municipal wastewater treatment plants (WWTPs) should be prevented. One way to do this is to promote the biological conversion of dissolved methane over stripping in aeration tanks. In this study, the well-established Activated Sludge Model n°1 (ASM1) and Benchmark Simulation Model n°1 (BSM1) were extended to study the influence of process design and operating parameters on biological methane oxidation. The aeration function used in BSM 1 was upgraded to more accurately describe gas–liquid transfer of oxygen and methane in aeration tanks equipped with subsurface aeration. Dissolved methane could be effectively removed in an aeration tank at an aeration rate that is in agreement with optimal effluent quality. Subsurface bubble aeration proved to be better than surface aeration, while a CSTR configuration was superior to plug flow conditions in avoiding methane emissions. The conversion of methane in the activated sludge tank benefits from higher methane concentrations in the WWTP's influent. Finally, if an activated sludge tank is aerated with methane containing off-gas, a limited amount of methane is absorbed and converted in the mixed liquor. This knowledge helps to stimulate the methane oxidizing capacity of activated sludge in order to abate methane emissions from wastewater treatment to the atmosphere.

Significance of settling model structures and parameter subsets in modelling WWTPs under wet-weather flow and filamentous bulking conditions

Current research focuses on predicting and mitigating the impacts of high hydraulic loadings on centralized wastewater treatment plants (WWTPs) under wet-weather conditions. The maximum permissible inflow to WWTPs depends not only on the settleability of activated sludge in secondary settling tanks (SSTs) but also on the hydraulic behaviour of SSTs. The present study investigates the impacts of ideal and non-ideal flow (dry and wet weather) and settling (good settling and bulking) boundary conditions on the sensitivity of WWTP model outputs to uncertainties intrinsic to the one-dimensional (1-D) SST model structures and parameters. We identify the critical sources of uncertainty in WWTP models through global sensitivity analysis (GSA) using the Benchmark simulation model No. 1 in combination with first- and second-order 1-D SST models. The results obtained illustrate that the contribution of settling parameters to the total variance of the key WWTP process outputs significantly depends on the influent flow and settling conditions. The magnitude of the impact is found to vary, depending on which type of 1-D SST model is used. Therefore, we identify and recommend potential parameter subsets for WWTP model calibration, and propose optimal choice of 1-D SST models under different flow and settling boundary conditions. Additionally, the hydraulic parameters in the second-order SST model are found significant under dynamic wet-weather flow conditions. These results highlight the importance of developing a more mechanistic based flow-dependent hydraulic sub-model in second-order 1-D SST models in the future.

Microbial diversity in tanning wastewaters treatment reactors

Diversity of the microbial consortia involved in biodegradation of unhairing wastewater from tanneries was assessed. Both culture-dependent and culture-independent approaches were applied to identify bacteria in the activated sludge and endogenous biomass systems. Conventional culturing using dilution and planting techniques yielded eighteen pure bacterial isolates from endogenous biomass and activated sludge reactors. Isolates were identified using sequence analysis of PCR-amplified 16S rRNA sequences. Most of these bacteria belonged to the genus Bacillus. Culture-independent molecular studies of bacterial diversity in both reactors, however, revealed a wide diversity of microorganisms, including members of the Proteobacteria group. Therefore, the alpha Proteobacteria group in the endogenous biomass was characterized by the genus Pseudochrobactrum, which was absent from the activated sludge biomass. The 77 and 88 bacterial clone sequences recovered from the activated sludge reactor and the endogenous biomass reactor, respectively, were grouped into 23 Operational Taxonomic Units (OTUs). The Proteobacteria division represented the predominant phylogenetic group within the clone library, encompassing 52.17% and 60.75% of the total OTUs obtained from the activated sludge and endogenous biomass tanks, respectively. The diversity in both tanks was also determined. The rarefaction curves and Shannon index indicated that bacterial populations were equally diverse in both reactors. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 401–410, 2015

Sorption of Perfluorinated Compounds onto different types of sewage sludge and assessment of its importance during wastewater treatment

The distribution coefficient (Kd) and the organic carbon distribution coefficient (KOC) were determined for four Perfluorinated Compounds (PFCs) to three different types of sludge taken from a conventional Sewage Treatment Plant (STP). Batch experiments were performed in six different environmental relevant concentrations (200ngL−1to 5μgL−1) containing 1gL−1 sludge. Kd values ranged from 330 to 6015, 329 to 17432 and 162 to 11770Lkg−1 for primary, secondary and digested sludge, respectively.The effects of solution’s pH, ionic strength and cation types on PFCs sorption were also evaluated. Sorption capacities of PFCs significantly decreased with increased pH values from 6 to 8. Furthermore, the divalent cation (Ca2+) enhanced PFCs sorption to a higher degree in comparison with the monovalent cation (Na+) at the same ionic strength.The obtained Kd values were applied to estimate the sorbed fractions of each PFC in different stages of a typical STP and to calculate their removal through treated wastewater and sludge. In primary settling tank, the predicted sorbed fractions ranged from 3% for Perfluorooctanoic Acid (PFOA) to 55% for Perfluoroundecanoic acid (PFUdA), while in activated sludge tank and anaerobic digester sorption was more than 50% for all target compounds. Almost 86% of initial PFOA load is expected to be detected in treated wastewater; while Perfluorodecanoic acid (PFDA), PFUdA and Perfluorooctanesulfonate (PFOS) can be significantly removed (>49%) via sorption to primary and excess secondary sludge. In anaerobic digester, the major part (>76%) of target PFCs is expected to be sorbed to sludge, while almost 3% of initial PFOA load will be detected in sludge leachates.

Anaerobic digestion of waste from a slaughterhouse

This paper investigates the effects of variation in the inoculum to waste ratio on the anaerobic treatment of slaughterhouse waste, and proposes a low cost anaerobic treatment system. The work was carried out using a laboratory scale packed anaerobic digester with a gas collecting chamber. The inoculum used for seeding the reactors was septic tank sludge. The operating temperature ranged from 28 to 37 °C. The experimental results indicated chemical oxygen demand (COD) removal efficiencies ranged from 60 to 90% and increased with increasing inoculum to waste ratio beyond (1:1). The decrease in the temperature (from 37 to 28 °C) reduced the COD removal efficiency from 90 to 75%. The system did not show any sign of destabilization under intermittent mode of operation of the reactors.

A new configuration of sequencing batch reactor operated as a modified aerobic/extended-idle regime for simultaneously saving reactor volume and enhancing biological phosphorus removal

Recently, it has been reported that the aerobic/extended-idle (AEI) regime can achieve a satisfied biological phosphorus removal (BPR). Although the AEI regime has exhibited some merits, its main drawback that the extended-idle phase (e.g., 210–450min) is much longer than the anaerobic phase (e.g., 60–120min) performed in the aerobic/oxic (A/O) regime requires to be addressed. In this study, a new configuration of sequencing batch reactor (SBR) with sludge tank halved (STH-SBR) was therefore designed. After stable operation, 96.9±0.5% of total phosphorus was removed in the STH-SBR, which was higher than that in the AEI-SBR (86.9±0.8%) and A/O-SBR (84.7±1.3%). Further investigations showed that the biomass cultured in the STH-SBR contained more polyphosphate accumulating organisms but less glycogen accumulating organisms than that in the AEI-SBR and A/O-SBR. In the STH-SBR, the aerobic glycogen accumulation was lower than that in the A/O-SBR while the average idle phosphorus release was greater than that in the AEI-SBR. Finally, the key enzyme activities in the AEI and A/O regimes were compared for the first time, and the reasons for the AEI regime showing lower exopolyphosphatase and polyphosphate kinase activities were also discussed.

Exploiting the intrinsic hydrocarbon-degrading microbial capacities in oil tank bottom sludge and waste soil for sludge bioremediation

In this study, biological methods (biostimulation and bioaugmentation) were used to treat oil tank bottom sludge contaminated soils to total petroleum hydrocarbon (TPH) levels suitable for landfill disposal. The sludge’s hydrocarbon-degrading microbial capacities were initially compared to those from other contaminated environments using culture-based methods. Results indicated that a fungus, Scedosporium dominated the sludge microbial community. Its application in a nutrient formulation resulted in greater reduction in oil tank bottom sludge viscosity (44 %) and residual soil hydrocarbon compared to hydrocarbonoclastic microorganisms from other sources (26.7 % reduction in viscosity). Subsequent field-based experiments showed greater TPH reduction (54 %) in fungal-nutrient-treated sludge–waste soils than in naturally attenuated controls (22 %) over 49 days. 16S ribosomal ribonucleic acid and internal transcribed spacer region-based polymerase chain reactions and denaturing gradient gel electrophoresis analyses showed minimal effects on the microbial communities during this time. TPH reduction to landfill disposal levels occurred at a slower rate after this, falling below the 10,000 mg kg−1 legislated TPH disposal threshold earlier in amended samples (91.2 %; 9,500 mg kg−1) compared to the control (82 %; 17,000 mg kg−1) in 182 days. The results show that the intrinsic hydrocarbon-degrading microbial capacities in sludge are better suited for sludge degradation than those from other sources. The substantial TPH reduction observed in control samples demonstrates the beneficial effects of natural attenuation with waste soils for oil tank sludge treatment. Microbial capacities in sludge and treated waste soils can therefore be successfully employed for treating oil tank bottom sludge.

염색공단폐수의 색도처리를 위한 염료분해 균주의 분리와 특성

Abstract To treat chromaticity contained in effluents of dyeing wastewater efficiently, potent dye-degrading microorganisms were isolated from influent water, aeration- tank sludge, recycle water and settling-tank sludge located in leather and dyeing treatment plant. Six potent strains were finally isolated and identified as Comamonas testosteroni , Methylobacteriaceae bacterium, Stenotrophomonas sp., Kluyveromyces fragilis , Ascomycetes sp. and Basidiomycetes sp. When Basidiomycetes sp. was inoculated into ME medium containing basal mixed-dyes, 93% of color was removed after 8 days incubation. In the same experiment, the 1:1 mixed culture of Basidiomycetes sp. and photosynthetic bacterium exhibited 88% of color removal; however, it showed better color removal for single-color dyes. The aeration-tank and settling-tank samples revealed higher color removal (95-96%) for black dyes. The settling-tank sample also revealed higher color removal on basal mixed-dyes, which resulted in 90% color removal after 6-h incubation. From the above results, it is expected to achieve a higher color removal using the mixed microorganisms that were isolated from aeration-tank and settling-tank samples.