Pengaruh Kecepatan Pengadukan dan Jarak Elekroda terhadap Penurunan Kadar COD dan TSS pada Limbah Batik Menggunakan Metode Elektrokoagulasi

The existence of the textile industry, especially in batik production in the region, will certainly provide benefits to the area, because it can absorb labor from the area. However, where there are advantages, there will also be disadvantages, as is the case in this textile factory where the liquid waste produced has a negative impact on the environment. This liquid waste comes from the washing and coloring process which contains dyes, heavy metals, and high salt concentrations. This study examines batik waste from a textile factory using the electrocoagulation method with aluminum electrodes. Research on batik wastewater treatment has been carried out. The results of this study prove that the electrode distance and stirring speed variables affect the COD reduction efficiency and TSS reduction in batik waste. In general, the higher the stirring speed and the closer the electrode spacing, the higher the TSS and COD reduction efficiency. There is an optimal point for stirring speed, where the highest reduction in TSS and COD efficiency is obtained at a stirring speed of 200 rpm. From the variables studied, the optimal value for both variables was obtained, namely at the electrode distance of 1.6 and at a stirring speed of 200 rpm, with the result that the efficiency value obtained was a decrease in COD of 89.39% and a decrease in TSS of 90.45 %.

Reduction of River Pollutants with Raffia-Cord in Sail River Pekanbaru Indonesia

The Sail River has been polluted by various types of pollutants in Pekanbaru. Raffia-cord is shaped like a feather duster, made of raffia rope that has been smoothed and then woven like a feather duster. This research was conducted as an effort to reduce the river pollutants (nitrate, phosphate, ammonia, Pb, Cr, COD, and BOD5. The study was carried out in Sail River in March – April 2019 using the Completely Randomized Design (CRD) method with density variations: low density (P1), medium density (P2), and high density (P3). The average results showed that the decrease for nitrate was 0.075-0.117 mg/L (35-44%) from 0.136-0.347 mg/L; phosphate 0.205-0.267 mg/L (29-40%) from 0.339-0.381 mg/L; ammonia 0.027-0.076 mg/L (28-58%) from 0.093-0.108 mg/L. The decreasing effectiveness of P1, P2, and P3 for Pb were 67.146%, 70.465% and 67.242%; for Cr were 81.346%, 83.335% and 81.893%. The average COD reduction effectiveness were 38.7%; 46.9%; 42.5% while BOD5 were 71.4%, 74.1% and 69.5%. It was concluded that raffia-cord could be used to reducing nitrate, phosphate, and ammonia levels, raffia-cord was able to reduce the concentration of Pb and Cr but raffia-cord had no significant effect on decreasing COD and BOD5.

Performance of two parallel covered lagoon digesters in the treatment of pig farm wastewaters

Pig farming moves a large part of the Brazilian economy. However, due to the high polluting potential, alternatives to treat and take advantage of the effluents must be developed, being the use of digesters a possible solution. This study aimed to evaluate the performance of two parallel covered lagoon digesters (CLD) in the treatment of swine wastewater. Monitoring was performed on a farm installed in Teixeiras, Minas Gerais, Brazil, in terms of COD in the period from August 2018 to July 2019. The study demonstrated that COD removal efficiency in the CLD was 40.2 and 39.5%, which did not indicate a statistical difference at a 5% significance level. The two digesters in parallel were compatible with each other in terms of COD reduction. Furthermore, individually they did not present significant changes in their performance in the summer and winter periods.

Biodegradation of acid red 3BN dye in sequential batch reactor: parameters and kinetics studies

Textile and dye industries generate wastewater which is considered as highly polluted and carcinogenic. Due to this, treatment of wastewater is required earlier to discharge or recycle. In the present studies, treatment of dye bearing water (DBW) has been explored. The treatment was performed using activated sludge (mixed culture) for aerobic process in sequential batch reactor (SBR). The fill volume (V F) and fill time (t F) variation in the treatment of DBW was taken place. The initial value of dye concentration, chemical oxygen demand (COD), sludge, and hydraulic retention time (HRT) were found to play important role in the treatment. At optimum condition (HRT = 2.5 d), the 86.84% COD reduction of 190 mg/L COD, and 92.33% dye reduction of 339 mg/L dye were achieved. These values are equal to overall 94.85% dye reduction of 500 mg/L, and 93.15% COD reduction of 380 mg/L. As a result, 500 mg/L dye was reduced to 26 mg/L, and 380 mg/L COD was reduced to 25 mg/L. The biodegradation fitted to Monod kinetics, for which kinetics parameter values of specific growth rate constant of biomass µ = 0.0047 h−1, yield coefficient (Y) = 1.059, and substrate utilization rate (q) = 0.0044 h−1 were evaluated at HRT = 2.5 d. The results show, this process can be applied to treat Acid Red 3BN Dye Water (AR3BNDW).

Supercritical water oxidation of phenol and process enhancement with in situ formed Fe2O3 nano catalyst

During the past few decades, the treatment of hazardous waste and toxic phenolic compounds has become a major issue in the pharmaceutical, gas/oil, dying, and chemical industries. Considering polymerization and oxidation of phenolic compounds, supercritical water oxidation (SCWO) has gained special attention. The present study objective was to synthesize a novel in situ Fe2O3nano-catalyst in a counter-current mixing reactor by supercritical water oxidation (SCWO) method to evaluate the phenol oxidation and COD reduction at different operation conditions like oxidant ratios and concentrations. Synthesized nano-catalyst was characterized by powder X-ray diffraction (XRD) and transmission electron microscope (TEM). TEM results revealed the maximum average particle size of 26.18 and 16.20 nm for preheated and non-preheated oxidant configuration, respectively. XRD showed the clear peaks of hematite at a 2θ value of 24, 33, 35.5, 49.5, 54, 62, and 64 for both catalysts treated preheated and non-preheated oxidant configurations. The maximum COD reduction and phenol oxidation of about 93.5% and 99.9% were observed at an oxidant ratio of 1.5, 0.75 s, 25 MPa, and 380 °C with a non-preheated H2O2 oxidant, while in situ formed Fe2O3nano-catalyst showed the maximum phenol oxidation of 99.9% at 0.75 s, 1.5 oxidant ratio, 25 MPa, and 380 °C. Similarly, in situ formed Fe2O3 catalyst presented the highest COD reduction of 97.8% at 40 mM phenol concentration, 1.0 oxidant ratio, 0.75 s residence time, 380 °C, and 25 MPa. It is concluded and recommended that SCWO is a feasible and cost-effective alternative method for the destruction of contaminants in water which showed the complete conversion of phenol within less than 1 s and 1.5 oxidant ratio.

Biogas Production from Coffee Pulp and Chicken Feathers Using Liquid- and Solid-State Anaerobic Digestions

Agricultural waste, particularly lignocellulose, has been used in the second generation of biogas. Coffee pulp and chicken feathers can be developed as biogas raw materials because of their suitability as a biogas substrate. This study investigates the effect of the percentage of total solids (TS), carbon to nitrogen ratio (C/N, g/g), and delignification pretreatment on biogas production from coffee pulp and chicken feathers, and aims to compose kinetics using the modified Gompertz model. The results show that adjusting the percentage of TS at low-level speeds up the degradation process, which increases chemical oxygen demand (COD) reduction and biogas production. COD reduction and biogas production increase optimally at the 25 (g/g) C/N ratio. Pretreatment delignification aids microorganisms in substrate decomposition, resulting in faster COD reduction and biogas conversion. The 25% TS and 25 (g/g) C/N ratio with the delignification process achieved the best biogas production, with biogas production of 10,438.04 mL. The Gompertz method shows that the difference in TS percentage can influence biogas production. Moreover, the method shows that biogas production is higher with the delignification process than without it.

Evaluation of water lettuce, giant salvinia and water hyacinth systems in phytoremediation of domestic wastewater

The objective of this research was to ascertain the best conditions for efficient applications of water lettuce, giant salvinia and water hyacinth in improving the quality of low strength domestic wastewater. Water quality assessment of the wastewater samples before (influent) and after treatment (effluent) with effect to retention times (6, 12 and 24 h) was analysed. The outcome of the study at 6 h retention showed that water lettuce (6.8–7.0 pH, 50.5% colour, 46.7% biological oxygen demand (BOD) and 37.8% chemical oxygen demand (COD)), giant salvinia (6.9–7.1 pH, 40.5% colour, 60% BOD and 43.2% COD) and water hyacinth (6.7–6.9 pH, 45.5% colour, 53% BOD and 35.1% COD) reduction values were achieved. At 12 h retention, water lettuce (6.6–7.0 pH, 57.2% colour, 77.1% BOD and 74.6% COD), giant salvinia (6.4–6.8 pH, 81.1% colour, 66.7% BOD and 72.2% COD) and water hyacinth (6.4–6.7 pH, 61.9% colour, 70% BOD and 61.1% COD) reduction values were achieved. Similarly, for 24 h retention, water lettuce (6.6–7.0 pH, 76.7% colour, 53.2% BOD and 70.3% COD), giant salvinia (6.6–7.0 pH, 91.4% colour, 74.7% BOD and 81.0% COD) and water hyacinth (6.4–6.9 pH, 74% colour, 58% BOD and 67.2% COD) reduction values were achieved. These findings indicated that the retention times of 12 and 24 h provided suitable conditions to break down the organic contaminants present in the shallow ponds.