TREATMENT OF PARBOILED RICE MANUFACTURING WASTEWATER USINGANAEROBIC FIXED FILM FIXED BED REACTOR PACKED WITH SPECIAL MEDIA
Studies on bench scale reactors packed with two different media matrix – Biopac media and Fugino spirals were undertaken to determine the performance at various organic loading rate (OLR) and on one day hydraulic retention time (HRT). Parboiled rice mill wastewater depicted a COD/BOD ratio of 1.6 indicating good degradable nature of the wastewater. Four different organic loadings of 0.8, 1.6, 2.4 and 3.2 kg COD/m3/day were studied in detail. The results indicated BOD and COD removals in the range of 83.0-92.7% and 80.2-89.0% respectively with respect to Biopac media while it ranged between 79.4–90.6% and 76.7–86.1% respectively in case of Fugino spiral media. It is very clear from the results that, Biopac media packed fixed film reactor gave efficient removals compared to Fugino spiral media packed reactor. Volatile acid concentration was well within the congenial range in both the reactors and volatile acid to alkalinity ratio remained well below 0.8 indicating good performance of the reactors. pH of the treated effluent was in the range of 7.1–7.3 indicating good buffering in the system. Daily gas production was measured. This paper discusses in detail the feasibility of upflow anaerobic fixed film fixed bed reactors packed with special media matrix in treating the parboiled rice manufacturing wastewater. Comparative performance of two special media matrix i.e. Fugino Spirals and Special Ultraviolet Stabilized Biopac media in the treatment of parboiled rice manufacturing wastewater has been studied in detail.
Parboiled rice effluent: A wastewater niche for microalgae and cyanobacteria with growth coupled to comprehensive remediation and phosphorus biofertilization
Abstract The potential of microalgae and cyanobacteria for bioremediation of wastewater by nutrient uptake combined with simultaneous biomass production is a well recognized perception of today's world. The present study illustrates the treatment of a highly polluted wastewater generated during parboiling of paddy in rice mill industries, widely operational in developing countries where rice is the staple food crop, with the help of microalgal and cyanobacterial isolates capable of growing at high rates in parboiled rice mill effluent (RME). This endeavor leads to comprehensive bioremediation of the said effluent and subsequent use of the harvested biomass as slow release phosphorus biofertilizers and the treated effluent for crop irrigation. The RME-acclimatized algal consortium demonstrated highest growth in terms of fresh weight and greatest remediation efficiency at the end of 36 days' treatment of RME, with 93.9% phosphorus and 100% ammonia-nitrogen removal, 98.7%, 91.6% and 93.5% reduction in biological oxygen demand, chemical oxygen demand and total dissolved solid, respectively, and an increment of 186 ± 0.3 mg L − 1 dissolved oxygen, bringing down the pollutants level well below the discharge limits suggested by Central Pollution Control Board, India. Additionally, microalgae in the consortium aggregated in clumps spontaneously in presence of the filaments of Phormidium sp. facilitating easy harvest. The RME-acclimatized algal consortium demonstrated highest accumulation of polyphosphate (poly-P) (0.76 ± 0.01% of dry weight) as well as highest release of phosphorus in non-sterile soil emphasizing the essential role of soil phosphorus solubilizing organisms to leach soluble phosphorus from the insoluble poly-P present in the biomass. The rice seedlings watered with treated RME also showed improved growth effect on shoot height and leaf width. The study results establish the suitability of RME as an excellent growth media for microalgae and cyanobacteria.
Fully Integrated Bidirectional CMOS-MEMS Flow Sensor With Low Power Pulse Operation
Leveraging More-than-Moore technology, we demonstrate an integrated CMOS MEMS flow sensor via a very compact system on chip (SoC) that can sense the bidirectional N2 gas flow. Our SoC features a very low-noise instrumentation amplifier that is implemented on a CMOS wafer and serves as a readout integrated circuit for a thermoresistive micro-calorimetric flow sensor which is fabricated on a MEMS wafer. A compact heterogeneous integration is achieved by combining the two wafers via the proprietary InvenSense AlN process. The measured sensitivity of our CMOS MEMS flow sensor is 98 mV/sccm which is three times better than the state-of-the-art counterpart. The flow range measured by our SoC is from −26 to 26 m/s (from −50 to 50 sccm). Moreover, the pulsed heater operation makes this proposed SoC flow sensor a very low power (<9 mW) and, thus, a promising candidate for the Internet-of-Things applications in smart home/green buildings.