Amount Of Chemical Oxygen Demand Research Articles

Testing of various membranes for removal of chemical oxygen demand in real fresh human urine using a cross-flow filtration system

ABSTRACT Urine is primarily composed of water (about 95%), with urea (around 2%), creatinine (approximately 0.1%), uric acid (about 0.03%), and various ions. Although human urine constitutes 1% of the volume of domestic wastewater, it contains significant amounts of chemical oxygen demand (COD) (∼10%). This study focused on the elimination of COD in urine using a cross-flow filtration system and testing the effectiveness of various membranes (microfiltration (MCE01), ultrafiltration (UP005 and UP010), and nanofiltration (NP010 and NF270)). The steady-state flux of the NF270 membrane increased from 10.8 to 23.9 L/m2/h as the pressure increased from 10 to 25 bar. A significant COD removal efficiency was obtained for the NF270 membrane at an operating pressure of 25 bar. COD concentration decreased from 7,392 to 1,270 mg/L with 82.8% rejection. In contrast, none of the membranes performed well in terms of urea removal efficiency. According to the findings, urea concentration decreased from 6,712 to 6,043 mg/L with 9.9% rejection. Moreover, ion contents (calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), ammonium (NH4+), phosphate (PO43−), sulfate (SO42−), and chloride (Cl−)) of the membrane permeates were also measured.

Photo-alternating current-electrocoagulation technique: Studies on operating parameters for treatment of industrial wastewater

In this investigation, several electrochemical and advanced oxidation processes (AOPs), including photolysis (UV), direct/alternating current-electrocoagulation (DC/AC/EleC), and photo-direct/alternating current-electrocoagulation (UV/DC/AC/EleC) process were examined regarding their capacity in order to reduce the amount of chemical oxygen demand (COD) and color in distillery industrial wastewater (DIW), as well as the effect these factors have on the amount of electricity required to treat the wastewater. Experimental results showed that compared to single UV, DC/EleC, AC/EleC, and hybrid UV/DC/EleC processes, the hybrid UV/AC/EleC process provided excellent color-100 % and COD-100 % removal efficiencies with a lowered usage of energy of 8.54 kWhr m−3. The influence of critical operational variables such as treatment time (30–240 min), photo (8–40 W), pulse duty cycle (0.14–0.86), current (0.15–0.90 Amp), pH (1.50–11.50), chemical oxygen demand (3000–9000 mgL−1), inter electrode spacing (1–4 cm), electrode combination (Fe/Fe, Fe/Al,Al/Fe, Al/Al), and electrolyte concentration (1–5 g L−1) on the efficiency of% color and COD removal, as well as the energy utilization of DIW were examined applying a hybrid UV/AC/EleC method. The synergistic index between UV and the AC/EleC process was also examined and discussed in this work. The UV/AC/EleC technique is the most advantageous choice in comparison to the other approaches since it can be applied to properly and efficiently remove pollutants from wastewater and industrial effluent.

Operational analysis of the biological treatment unit's ultraviolet-wave disinfection method for wastewater outflow

Wastewater can be contaminated with all kinds of microorganisms and small organisms, including bacteria, parasites, fungi and viruses. Therefore, it can be said that biological pollution is one of the most dangerous pollutions. These types of pollution can endanger human health and the environment. In this study, industrial wastewater disinfection has been investigated in a laboratory pilot. In this study, ultraviolet waves have been used for wastewater disinfection. In this research, treatment indicators such as wastewater pH, phosphate, nitrate, biological oxygen and chemical oxygen, organic carbon, and wastewater turbidity have been investigated. The results of this research show that if 4.5 g of dry ice is added to the wastewater entering the disinfection unit, the pH of the wastewater will decrease to about 7.9. The results presented from the disinfection unit show that the amount of chemical oxygen demand and biological oxygen demand have decreased by about 35% and 20.3%, respectively. The results of this unit show that the amount of phosphate and nitrate has decreased by 61.3 and 71.9%, respectively. Laboratory results show that the TDS of wastewater has decreased from 600 to 451 mg/l.

Sensing of chemical oxygen demand (COD) by amperometric detection—dependence of current signal on concentration and type of organic species

The standard method to determine chemical oxygen demand (COD) with K2Cr2O6 uses harmful chemicals, has a long analysis time, and cannot be used for on-site online monitoring. It is therefore necessary to find a fast, cheap, and harmless alternative. The amperometric determination of COD on boron-doped diamond (BDD) electrodes is a promising approach. However, to be a suitable alternative, the electrochemical method must at least be able to determine the COD of water samples independently of the contained substances. Therefore, the current signal as a function of various organic materials was investigated for the first time. It was shown that the height of the signal current depended on the type of organic matter in single-substance solutions and that this substance dependency increases with the amount of COD. Those findings could be explained by the mechanism proposed for this reaction, showing that the selectivity of the reaction depends on the ratio of the concentration of hydroxyl radicals and organic species. We give an outlook on how to improve the method in order to increase the linear working range and avoid signal variance and how to further explain the signal variance.

Coupling of the optimized electro-Fenton-like process with pulsed laser ablation method to produce bimetallic nanoparticles of Fe°/Cu° and Fe°/Zn° in treatment of thiophene aqueous samples

In this study, an electro-Fenton-like method in the presence of iron particles was used for degradation of toxic thiophene pollutant from aqueous samples with performance > 99%. In an electrolytic reactor, the effect of current density, H2O2 dosage and pH of the sample on the treatment efficiency was investigated and optimized using response surface method in experimental design methodology. The conditions were optimized in current density 20 mA/cm2, H2O2 dosage 500 ppm and pH = 3.0. In this process, a laser pulse ablation was used to produce iron nanoparticles in the electro-Fenton reactor to decrease the treatment time. Also, two bimetallic iron-copper and iron-zinc were used to investigate the synergistic effect of bimetallic catalyst on degradation efficiency of thiophene. The removal of thiophene nearly 100% can be provided in presence Fe0.5/Cu0.5, Fe0.5/Zn0.5 and Fe alone in 10, 15 and 20 minutes, respectively. Also, the effect of hydroxyl scavenger and the consumption of catalysts were studied in the proposed procedure. Techniques of gas chromatography-flame ionization detector (GC-FID), gas chromatography-sulfur chemiluminescence detector (GC-SCD) and total sulfur analyzer were used to follow thiophene degradation. A thiophene petrochemical wastewater was treated by the proposed method and the results showed significant reduction of amounts of Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD).

Evaluation and improvement of the WWTP performance of an agricultural cooperative by adsorption on inert biomaterial: case of orthophosphate, nitrate and sulfate ions

The study is carried out at the wastewater treatment plant (WWTP) of an agricultural cooperative that operates according to the activated sludge process. Dairy industry is enlisted as one of the top-most industries in the food industry. Dairy wastewater treatment is a big issue as dairy wastewater releases a high amount of chemical oxygen demand, inorganic and organic particles, biological oxygen demand, and nutrients. But, these processes partly degrade wastewater containing fats and nutrients as dairy wastewater. The aim of this study was to evaluate the purification performance of this treatment process. The qualitative analysis of decanted raw wastewater (DRWW) and purified wastewater (PWW) shows that the concentration of orthophosphate, nitrate and sulfate ions is slightly higher. Such contaminated water if not handled appropriately, it pollutes water bodies and largely affects our ecosystem and biodiversity. Hence, our proposal is to improve the WWTP performances by using the adsorption process onto dried Carpobrotus edulis as an inert biomaterial. This adsorption process is recognized as one of the best water treatment techniques, more and more works are oriented towards the search for new materials, cheaper and having a good adsorbent potential. This study opens the path for the use of natural and abundant local material to remove orthophosphate, nitrate and sulfate ions using the C. edulis plant particles shred. The surface micromorphology of the biomaterial was investigated using a scanning electron microscope; while the qualitative element composition was analyzed using energy dispersive X-ray and infrared spectroscopies. The found results of DRWW was about 57% for orthophosphates, 67% for sulfates and 73% for nitrates ions. For PWW, the percentage removal was found to be 62%, 73% and 84% for orthophosphates, sulfates and nitrates respectively. These results indicate that dried C. edulis plant, as an environmentally friendly adsorbent could be recommended for the removal of mineral pollutants. In conclusion, the C. edulis adsorbent can be integrated into the activated sludge process for wastewater treatment after identifying the optimal hydraulic loads, associated sizes, and shapes in continuous operations.

Performance Monitoring of Anaerobic Digestion at Various Organic Loading Rates of Commercial Malaysian Food Waste.

Application of anaerobic digestion (AD) has become common in treating palm oil mill effluent in Malaysia; however, employing AD in treating the organic fraction of municipal solid waste (OFMSW), especially food waste, is still scarce. This study aims to characterize the commercial Malaysian food waste (CMFW) and determine its potential as sustainable bioenergy feedstock through biogas production. The sample was digested via the biomethane potential (BMP) test with the variation of organic loading rates (OLRs), ranging from 0.38 to 3.83 gCOD/L. day, under mesophilic conditions. The digestion process was further evaluated in continuous operation using a 6-L continuous stirred-tank reactor (CSTR). The kinetic properties of the process were also determined. It was found that the CMFW had a significant amount of chemical oxygen demand of 230 g/L and an acidic pH of 4.5 with the carbon to nitrogen (C/N) ratio at 121:1. A maximum methane composition of 81% was obtained at 1.92 gCOD/L in the BMP test with specific methane production (SMP) at 0.952 L. CH4/L.COD fed. The biogas production was well-fitted with the modified Gompertz model with R 2 at 0.9983 and the maximum biogas potential production rate at Rm 0.1573 L/day, whereas in the CSTR operation, a maximum methane composition of 85% was produced at OLR 6 gCOD/L. day with the SMP of 1.13 L. CH4/L.COD fed. The CSTR system was in high stability as the pH was maintained in a range of 6.6–6.7, with an alkalinity ratio of 0.28. This study indicates the CMFW is a sustainable feedstock for biogas production in Malaysia. Toward a circular economy approach, the authorities shall introduce commercial scale CMFW AD as part of managing municipal solid waste issues in Malaysia.

Applications of Sponge Iron and Effects of Organic Carbon Source on Sulfate-Reducing Ammonium Oxidation Process.

The typical characteristics of wastewater produced from seafood, chemical, textile, and paper industries are that it contains ammonia, sulfate, and a certain amount of chemical oxygen demand (COD). The sulfate-reducing ammonium oxidation process is a biochemical reaction that allows both ammonia and sulfate removal, but its low growth rate and harsh reaction conditions limit its practical application. Due to the adsorption properties of the iron sponge and its robust structure, it provides a suitable living environment for microorganisms. To reduce the negative impact on the environment, we employed 4.8 kg of sponge iron in a 2.0 dm3 anaerobic sequencing batch reactor (ASBR). We investigated the effects of the type and concentration of carbon sources on the performance of the sulfate-reducing ammonium oxidation (SRAO) process. The results demonstrated that during a start-up period of 90 days, the average ammonium removal efficiency and the sulfate conversion efficiency of the reactor containing the sponge iron were 4.42% and 8.37% higher than those of the reactor without the sponge iron. The addition of the sponge iron shortens the start-up time of this greenhouse gas-free denitrification process and reduces future costs in practical applications. The removal of total nitrogen (TN) significantly increased after adding organic carbon sources and then declined sharply, while the most considerable reduction of ammonium removal efficiency from 98.4% to 30.5% was observed with adding phenol. The performance of the group employing glucose as the carbon source was recovered on the 28th day, with the average ammonium removal efficiency increasing from 49.03% to 83.5%. The results of this simulation study will help the rapid start-up of SRAO in the water treatment industry and can precisely guide the application of the SRAO process for wastewater containing different organic carbon sources.

Photocatalytic Hydrogen Production from Urine Using Sr-Doped TiO2 Photocatalyst with Subsequent Phosphorus Recovery via Struvite Crystallization

Currently, the discharge of wastewater and utilization of phosphorus (P) in human activities cause some environmental problems, such as high organic pollutants in aquatic environments which results in dirty water sources, and a shortage of phosphate rock reserves due to the high demand of P. Therefore, fuel energy and struvite crystallization from waste sources can be considered interesting alternatives. In this work, the modified catalyst for hydrogen production, along with solving environmental problems, was examined. The strontium (Sr) doped-titanium dioxide (TiO2) nanoparticles were synthesized by wetness impregnation method. The synthesized catalyst was characterized using UV-vis spectroscopy (UV-vis), photoluminescence (PL), X-ray diffraction (XRD), photoluminescence (PL), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). The Sr-doped TiO2 catalysts had been utilized as the photocatalyst for the hydrogen production from synthetic human urine (a representative of waste source). The doping content of Sr in TiO2 varied from 0.5, 1, 2, and 4%, and the photocatalytic performances were compared with pristine TiO2 nanoparticles. The results showed that 1% Sr-doped TiO2 had the highest photocatalytic activity for hydrogen production and decreased the amount of chemical oxygen demand (COD) in the synthetic human urine. Subsequently, P could be recovered from the treated human urine in the form of struvite.

Extraction of Bio Polymers from Crustacean Shells and its Application in Refinery Wastewater Treatment

The fisheries sector is one of the most ancient and important sectors in the world and plays a significant role in providing the nutrition and socio-economic development of the country. The fish processing industry produces huge quantities of wastewater, encompassing significant amounts of contaminants in the form of soluble, colloidal, and particulate matters. The disposal of shellfish waste is a serious issue, and the effluents discharged from seafood-processing plants contain high amounts of Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), dissolved solids, suspended solids, and turbidity. The existing waste management system lacks a cost-effective and environmentally friendly method. The current research focus on the extraction of a biopolymer chitosan from crab shells by ecofriendly methods and its application in refinery wastewater treatment. The chemical structure and crystallinity of the extracted chitosan was confirmed by Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD) analyses. Surface morphology and elemental composition were determined using Scanning Electron Microscopy (SEM), and Energy-Dispersive X-Ray Analysis (EDX). Thermal properties were detected using Thermo Gravimetric Analysis (TGA). The extracted chitosan was successfully employed in the batch treatment of refinery effluent by varying the experimental parameters (refinery effluent solution pH, contact time, dosage of chitosan, and stirring speed) and the optimizations of the processing conditions were established.

Treatment of real industrial pharmaceutical wastewater using wet peroxide oxidation

AbstractThe presence of recalcitrant organic molecules with high amounts of chemical oxygen demand, low biodegradability, and lack of effective treatment for pharmaceutical wastewater result in environmental pollution. Batch wet peroxide oxidation (WPO) experiments have been performed to study the effect of temperature (150°C‐250°C), oxidant coefficient (OC 0‐3), and reaction time (20 minutes‐60 minutes) on degradation efficiency of industrial pharmaceutical wastewater. Box‐Behnken design (BBD) with response surface methodology was used to study the effect of independent parameters on total organic carbon (TOC) removal response. The optimum temperature, oxidant coefficient, and reaction time of the process were found to be 250°C, OC 3, and 60 minutes, which resulted in TOC conversion of 57.96%. The obtained quadratic model has been able to predict the response with minimum deviation. The experimental modelling results conveyed that influence of process parameters followed the order: temperature > time > oxidant coefficient. To improve the mineralization efficiency, process parameters were changed to attain the near complete conversion (~99%) of the pharmaceutical wastewater. The qualitative analysis also showed that only a few components of pharmaceuticals were present in the treated effluent.

Estimating the chemical oxygen demand of petrochemical wastewater treatment plants using linear and nonlinear statistical models – A case study

In this research, twelve linear and nonlinear regression models were performed and evaluated to formulate the best one for the estimation of chemical oxygen demand level in the effluent of the clarifier unit of a petrochemical wastewater treatment plant. The input variables measured twice a day in the influent of the biological unit over a period of 13 months using standard methods. The piece-wise linear regression with breakpoint method, with a mean squared error value equal to 0.041, mean absolute error of 0.144, and correlation coefficient equal to 0.835 was found to estimate the output chemical oxygen demand parameter more sustainable rather than other linear and nonlinear methods. However, some of the other applied models such as radial basis function neural network and gene expressing programming models achieved good performance considering their correlation coefficient, robustness in presence of outliers, mean squared error and mean absolute error test. Mathematical and intelligent modeling proved useful as an accurate alternative to estimate the amount of chemical oxygen demand rather than spending time and cost for its laboratory tests.

Phytoremediation of palm oil mill effluent (POME) using water spinach (Ipomoea aquatica Forsk)

Rapid expansion of palm oil industry poses potential threat to terrestrial environment and aquatic ecosystems as it discharges high volume and various forms of solid and liquid waste substances as by-products, known as palm oil mill effluent (POME) during oil processing. Indiscremental disposal of POME is a major source of wastewater contamination which could have catastrophic impact on the environment. Thus, remediation of POME is crucial before it released to the environment. Phytoremediation using aquatic plants including water spinach (Ipomoea aquatica) has potential to improve the quality of POME. This present study investigated the phytoremediation efficiency of POME, which contains high amount of chemical oxygen demand (COD), nitrate, phosphate using water spinach for up to 15 days and described its impact on the growth performance. Experimental design of this study consisted of five treatments with three replications namely: control: 0% POME (0 L POME + 10 L tap water), Treatment A: 25% POME (2.5 L POME + 7.5 L tap water), Treatment B: 50% POME (5 L POME+ 5 L tap water), Treatment C: 75% POME (7.5 L POME + 2.5 L tap water), and Treatment D: 100% POME (10 L POME). The results indicated that water spinach was able to reduce COD, nitrate, phosphate and color as 86.3%, 21.5%, 90.9 % and 95.3%, respectively. Water spinach had no influence on the growth performance even up to 75% of POME containing media. Furthermore, results showed that high concentrations of POME damage root structures, and ultimately impact the growth performance of water spinach. In conclusion, phytoremediation using water spinach can be a potential remediation method to improve the quality of COD, phosphate and nitrate.

Cleaner strategies on the effective elimination of toxic chromium from wastewater using coupled electrochemical/biological systems

AbstractHexavalent chromium is a toxic pollutant and carcinogen, which affects the organs internally as well as externally in our body. In this research, a combination of three‐dimensional (3D)‐electrochemical treatment followed by biological treatment was done for chromium removal in simulated wastewater. Surface‐modified Strychnos potatorum (SMSp) seeds and surface‐modified tamarind pod (SMTp) shell were used as particle electrodes, and the experiments were conducted for different pH, voltage, and particle electrode followed by biological treatment. In biological treatment, Enterobacter cloacae strain was isolated from a common effluent treatment plant (CETP) and it was utilized. The molecular characterization of E. cloacae (live biomass) was done using 16s rRNA sequencing. In 3D‐electrochemical treatment with SMSp, efficiency was found to be the best when compared with SMTp under optimum condition (6 V, 3 pH, 15 g of SMSp) at a working period of 60 min, and the removal of hexavalent chromium from aqueous solution using SMSp was successfully applied to semi‐empirical kinetic model, which is based on Fermi's equation. This semi‐empirical kinetic model effectively depicts the hexavalent chromium concentration evolution in 3D‐electrochemical treatment. The combined treatment reduced the amount of chemical oxygen demand as well as the hexavalent chromium‐ion concentration in aqueous solution.

Culturing of green photosynthetic microalgae (Chlorella sp.) using palm oil mill effluent (POME) for future biodiesel production

Nowadays, the water pollution is leading issue due to palm oil mill effluent (POME), waste from palm oil production is a big problem to Malaysia which is largest palm oil producers. POME containing large amount of chemical oxygen demand (COD) which can cause severe pollution to the environment especially water. This present study designed for culturing green algae (Chlorella sp.) isolated from Pantai Balok, Kuantan which is most common microalgae with palm oil mill effluent (POME). Chlorella sp. was cultured using BG-11 medium with the addition of POME as experiment and without POME as control. The POME responsible for the growth of green algae is studied by measurement of the growth rate, total cell count and chemical oxygen demand (COD) for both conditions. The composition for control and experiment is also measured and determined by using Gas Chromatography Mass Spectrometry (GCMS). From the results, it is observed that the total cell count and growth rate of Chlorella sp. greater in presence of POME since the green microalgae absorbs the essential nutrients from the POME as their nutrients. GCMS revealed that the difference in composition for both the conditions. Results concluded that several COD also vigorously deplete with the help of green algae digestion. Cultivation of Chlorella sp. in POME will help in future water pollution treatment.

Water Degradation by China’s Fossil Fuels Production: A Life Cycle Assessment Based on an Input–Output Model

Fossil energy production not only aggravates water depletion but also severely contaminates water resources. This study employed a mixed-unit input–output model to give a life cycle assessment of national average water degradation in production of common types of fossil fuels in China. The results show that the amount of grey water generated is much more than that of consumptive and withdrawn water in all cases. Although there is a high discharge amount of chemical oxygen demand (COD) in fossil fuel production, the pollutants of petroleum (PE) and volatile phenols (VP) require more dilution water than COD. PE is the greatest contributor to water degradation caused by primary fossil fuels, while VP pollution is prominent in production of upgraded fossil fuels. Basically, the main causes of water degradation, PE and VP discharge, occurs at coal mines, oil fields, refinery plants, and coking factories, rather than in the upstream sectors. A scenario analysis showed that water pollution can be significantly reduced if VP discharge in the coking process is controlled to be at the standard concentration. PE requires a standard withalower discharge concentration in order to further mitigate water pollution in production of fossil fuels. The coal production industry has a much lower pollutant removal rate but spends more on wastewater treatment, up to 12% of its profit. The other fossil fuel industries have high removal rates of PE and VP (97%–99%) and thus demand technological renovation to further remove those pollutants at a low concentration.

Effect of adding microorganism and carbon source to substrate on nitrogen removal treating the drainage of WWTP.

Developing substrate with carbon release properties is helpful to enhance nitrogen removal in low C/N ratio wastewater treatment. In this study, substrates with and without adding carbon source and microorganism were prepared to treat the drainage effluent from a wastewater treatment plant (WWTP), the difference in nitrogen removal were investigated. The results showed that adding a carbon source and microorganism to substrates could not only increase the amount of chemical oxygen demand (COD) released, but also enhance the adsorption capacities of NH4 +-N and NO3 --N. The carbon release process followed the first-order kinetic equation. A nitrogen removal model consisting of four phases of diffusion, adsorption, assimilation and transformation was proposed. In the short term, nitrogen was mainly removed by adsorption; adding microorganism contributed to enhance nitrification and denitrification. In the long-term, nitrogen removal performances were similar whether microorganism was added or not, and microbial species on the surface of substrates were similar. This work suggested when using substrate to treat wastewater for nitrogen removal, preparing a substrate with excellent property for biofilm formation was the most important factor.

Removal of Pharmaceuticals From Aqueous Medium Using Entrapped Activated Carbon in Alginate

The adsorption of entrapped activated carbon in alginate polymer (AG–AC) was investigated by measuring the removal of organic compounds. The general concept is that the entrapped activated carbon in alginate polymer could be used as a low–cost adsorbent for ascorbic acid and lactose removal from industrial wastewater. Ascorbic acid and lactose are the most pharmaceutical wastes that can introduce throughout the industrial process and lead to an increase in the amount of chemical oxygen demand (COD) in wastewater. Different ascorbic acid and lactose concentrations were prepared in the laboratory. The efficient removal is affected by external variables (eg, pH, contact time, adsorbent dosage, concentrations, and stirring rate). Percent removal for ascorbic acid and lactose at pH 3 using dose 30 g for 60 minutes with a fixed stirring rate at 100 rpm was about 70% and 50%, respectively. Ascorbic acid and lactose adsorption onto entrapped activated carbon in alginate polymer obey well with Freundlich adsorption isotherm.

Auto-flocculation through cultivation of Chlorella vulgaris in seafood wastewater discharge: Influence of culture conditions on microalgae growth and nutrient removal

Nowadays, the pretreatment of wastewater prior to discharge is very important in various industries as the wastewater without any treatment contains high organic pollution loads that would pollute the receiving waterbody and potentially cause eutrophication and oxygen depletion to aquatic life. The reuse of seafood wastewater discharge in microalgae cultivation offers beneficial purposes such as reduced processing cost for wastewater treatment, replenishing ground water basin as well as financial savings for microalgae cultivation. In this paper, the cultivation of Chlorella vulgaris with an initial concentration of 0.01±0.001g⋅L-1 using seafood sewage discharge under sunlight and fluorescent illumination was investigated in laboratory-scale without adjusting mineral nutrients and pH. The ability of nutrient removal under different lighting conditions, the metabolism of C.vulgaris and new medium as well as the occurrence of auto-flocculation of microalgae biomass were evaluated for 14 days. The results showed that different illumination sources did not influence the microalgae growth, chemical oxygen demand (COD) and biochemical oxygen demand (BOD) significantly. However, the total nitrogen (total-N) and total phosphorus (total-P) contents of microalgae were sensitive to the illumination mode. The amount of COD, BOD, total-N and total-P were decreased by 88%, 81%, 95%, and 83% under sunlight mode and 81%, 74%, 79%, and 72% under fluorescent illumination, respectively. Furthermore, microalgae were auto-flocculated at the final days of cultivation with maximum biomass concentration of 0.49±0.01g⋅L-1, and the pH value had increased to pH 9.8±0.1 under sunlight illumination.

Utilization of bamboo water plant (Equisetum hyemale) in reducing chemical oxygen demand level of laboratory waste

Laboratory as one of the supporting facilities of learning activities in various educational institutions, both at the primary level, intermediate and at higher education level, including in the Faculty of Health, Dian Nuswantoro University. As one of the indicators of laboratory waste pollution is the parameter of chemical oxygen demand. Utilization of bamboo water plant (Equisetum hyemale) as a remediation agent is an alternative treatment. Experiments were conducted experimentally using a completely randomized design with 75 plants, 150 plants, and 225 plants 3 and treatment (0 hours, 48 hours, 60 hours and 72 hours), by measuring the decrease in chemical oxygen demand concentrations. The best result was aimed at second treatment with chemical oxygen demand degraded is 430 ppm with regression equation rate y = 137x - 190 with best degradation ability. While treatment 1 with the amount of chemical oxygen demand degraded 10 ppm with the equation of degradation rate was y = 36x - 3, and treatment 3 with 334 ppm degraded chemical oxygen demand with degradation rate y = 112x – 151. Based on the analysis result showed Equisetum hyemale has been proven to be used as a phytoremediation agent which is quite effective in reducing the level of chemical oxygen demand, the most effective reduction of the concentration of chemical oxygen demand was found in the final treatment results using Equisetum hyemale 150 rods with the equation model y = 137x - 190 with R2 = 0.85.