Analysis of the effect of stirrer and container rotation direction on mixing index (Ip)

The paper discusses the effect of the stirrer and container rotation direction on the mixing index (Ip). The chaos theory is the result of an in-depth study of various problems that cannot be answered by the two previous major theories, namely quantum mechanics and the theory of relativity. Effective mixing of the flow area does not depend on rapid stirring. This study uses a container with a double stirrer, camera, programmable logic controller, tachometer, 6 A adapter, and a computer. DC electric motor (25 V) for turning stirrers and housings. The diameter of the primary and secondary stirrers is Dp=38 mm and Ds=17 mm. The diameter of the container made of transparent plastic is Dw=160 mm and height is 170 mm. Primary stirrer rotation (np)=10 rpm, secondary stirrer rotation (ns)=22.3 rpm, and container rotation (nw)=13 rpm, the angular velocity of the container is Ww=360° while the angular speed of the primary stirrer is Wp=180°. The liquid consists of a mixture of water and paint (white). For dye, a mixture of water and paint (red) is used. For testing the Brookfield viscometer, the viscosity of the liquid and dye is used. The results showed that turning the stirrer in the opposite direction to the container, there will be stretching, bending, and folding around the stirrer, and the smallest mixing index was P2V-b (0.94). In addition, based on the mixing index value above, the highest mixing effectiveness level is obtained, namely: P2V-b, P2S-b, P2B-b, P2V-a, P2B-a, and finally P2S-a. The mixing index is inversely related to the effectiveness level. So the highest effectiveness level is given by the following treatment: 1. Variation rotation (between opposite rotating mixers), 2. Opposite rotation (stirrer rotation opposite direction to the container), 3. Unidirectional rotation (stirrer rotation in the direction of the container)

Kajian Kinerja Organoclay Bentonit Terinterkalasi Poli-DADMAC sebagai Flokulasn Limbah Cair Tahu

Abstrak Telah dilakukan kajian kinerja organoclay bentonit terinterkalasi polyi-DADMAC sebagai flokulan limbah cair tahu. Tujuan dari penelitian ini adalah untuk menguji efektifitas organoclay bentonit terinterkalasi poly-DADMAC sebagai flokulan limbah cair tahu. Organoclay bentonit terinterkalasi poly-DADMAC disintesis dengan mereaksikan 10 g bentonit dengan 100 mL poly-DADMAC 4%. Pergeseran yang terjadi pada spektra hasil analisis XRD dan FTIR menunjukan keberhasilan proses interkalasi bentonit dengan poly-DADMAC. Koagulasi flokulasi dilakukan dengan metode jar test pada kecepatan pengadukan cepat 120 rpm selama 1 menit dan pengadukan lambat 20 rpm. Kajian kinerja flokulan organoclay meliputi variasi jenis flokulan, massa flokulan, lama waktu kontak flokulasi dan variasi jenis pengenceran. Nilai efektifitas penurunan COD maksimum pada 35.7 % terjadi pada penambahan jenis flokulan organoclay dengan massa 0.05 g dan waktu kontak flokulasi 40 menit. Proses koagulasi-flokulasi limbah cair tahu menggunakan flokulan organoclay mampu menghasilkan penurunan nilai COD limbah dari 1145.76 mg/L menjadi 833.28 mg/L. Akan tetapi., koagulasi-flokulasi limbah cair tahu pada penelitian ini tidak menurunkan pH limbah secara ekstrim, rentang penurunan pH adalah dari 3.836 menjadi 3.448. Kata kunci : Flokulan, organoclay, bentonit-polyDADMAC, limbah cair tahu Abstract Studies of Bentonite intercalated organoclay performance polyi-DADMAC as flocculants wastewater of tahu has been done. The purpose of this study was to examine the effectiveness of Bentonite intercalated organoclay poly-DADMAC as flocculants wastewater of Tahu. Bentonite intercalated organoclay poly-DADMAC are synthesized by reacting 10 g of bentonite with 100 mL of poly-DADMAC 4%. The shift in spectral analysis of XRD and FTIR results showed the success of the process of intercalation of bentonite with poly-DADMAC. Coagulation-flocculation using Jar test with the rapid stirring speed of 120 rpm for 1 minute and 20 rpm slow stirring. Organoclay flocculant performance review includes a variation type of flocculant, flocculant mass, contact time flocculation and variations in the type of dilution. Rated maximum effectiveness of COD reduction occurs at 35.7% in the type of flocculant addition of organoclay with a mass of 0.05 g and a contact time of 40 minutes flocculation. Coagulation-flocculation process of wastewater of Tahu using flocculants organoclay decrease COD from 1145.76 mg / L to 833.28 mg / L. However, coagulation-flocculation of wastewater of Tahu did not lower the pH of the waste significantly, decreasing pH occurs from 3.836 to 3.448.Keywords: Flocculant, organoclay, bentonite-polyDADMAC, wastewater of TahuDOI: http://dx.doi.org/10.15408/jkv.v0i0.4322

Study on Energy Consumption Distribution of High Ferric-Based Silicon Coagulant Using Fractal Dimension

High ferric-based silicon coagulant is a kind of new self-made coagulant. The high ferric content was introduced in the preparation process of the coagulant, and the effect was good in dealing with simulated industrial wastewater with lead. The beaker test indicated that the lead removal rate reached the highest 96.48% when the rapid stirring speed was 300r/min and stirring time was 1min, low stirring speed was 80r/min and stirring time was 15min, the dosage of the coagulant was 3.5ml/L. And the fractal dimension of flocs was 1.67674 under that optimum conditions. The low stirring stage was divided into three different stages in the orthogonal experiment of energy consumption, and the result showed that the optimum combination of flocculation was: velocity gradient G1=67.7s-1, stirring time T1=4min; G2=57.8 s-1, T2=5min; G3=23.9s-1, T3=6min. The removal rate of lead ion improved and the energy consumption decreased when the flocculation was divided into different stages. The relations between fractal dimension and energy consumption distribution can be obtained by calculated the fractal dimension of different stages. The stirring speed can be controlled and the flocs can be prevented from being broken by observing the flocs.

Carbon dioxide production in the oscillating Belousov—Zhabotinsky reaction with oxalic acid

A new volumetric method for monitoring the oscillating Belousov—Zhabotinsky reaction with oxalic acid is described. While an oscillatory behavior in the potential of the Pt redox electrode at slow stirring without inert gas bubbling can be observed, a monotonous, nonoscillatory course was found both at the slow and rapid stirring rates for the carbon dioxide evolution. Possible reasons for such observations are discussed.

Novel technology for improving the treatability of turbidizing substances by coagulation and sedimentation

Treatability in the coagulation and sedimentation of turbidizing substances varies greatly depending on the rapid stirring strength GR. It is demonstrated that when PACl coagulant is used, the optimum treatability is achieved at GR values of 450 for turbidity and 1,000 sec−1 for STR, a newly introduced evaluation parameter. These values are much higher than the values typical of many water purification plants where the GR values are set at 100~200 sec−1. The remarkable improvement of coagulation and sedimentation treatment is found to be related to the formation of denser, smaller-diameter microfloc with increasing GR, and an increase in the incorporation of coagulant-derived aluminium in the microfloc and zeta-potential of the microfloc, among other flock properties.