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Estimation of evapotranspiration (ET) parameters is essential for understanding crop water requirements and to find out the ground water recharge. In situ data collection procedures are generally adopted to measure the parameters required to find ET. Latest remote sensing technologies accompanied by newly launched satellite datasets can supplement the field data collection and analysis by finding out some of the parameters such as land surface temperature, normalized difference vegetation index (NDVI), albedo, emissivity, etc. The Upper Ganga Canal Command Area (UGC) lying between two rivers Ganga and Yamuna situated between two states, namely Uttarakhand and Uttar Pradesh in North India is selected as the study area for this research work. Operational Simplified Surface Energy Balance (SSEBop) method is used to derive high resolution (10m) ET map for the Upper Ganga Canal Command Area. Sentinel-2 multi spectral images were used to derive land use, land cover (LU/LC) maps, NDVI, albedo, etc. Downscaled Landsat 8 images were used to derive land surface temperature of the command area. Meteorological data retrieved from the Indian Meteorological Department (IMD) was used to calculate reference evapotranspiration. ET map of the study area was generated using the above estimated parameters. Further, validation of the obtained ET values was accomplished by gridded ET data obtained from IMD.

Ganga River Basin (GRB) is the second most populous river basin in the world, which has been undergoing rapid land-use change during the last few decades. Here, we analyse the landscape dynamics in Indian GRB (IGRB) using three indices, i.e. class area, mean patch size and number of patches for 14 land-use and land-cover (LULU) classes using multi-temporal Landsat satellite datasets of 1975 and 2010. Major change was observed with the expansion of agricultural lands and human settlements and depletion of forests. Agricultural lands covered the highest area (>75%), where low to medium-sized patches have increased and patches with larger size have been slightly reduced in size over past decades. The highest increase in percentage of built-up land has been appropriately captured on medium-resolution satellite imageries using visual interpretation technique. Degradation and loss of forest areas were reported in terms of landscape indices; however, the increase of plantation is a positive sign in the basin. In general, we observed aggregation of agricultural patches and reduction of forest patches in small to medium patch sizes. We argue the utility of 'onscreen visual interpretation' technique in favour of LULC mapping to achieve absolute accuracy in such a heterogeneous landscape, as it incorporates interpreter's knowledge. We appreciate the free availability of Landsat imageries having very good radiometry that has opened the doors for exercises with minimum cost. Located in one of the most fertile regions of India, the basin accommodates more than 400 million human population. This has led to expansion of agriculture and built-up land at the cost of forest and other land covers. Understanding landscape dynamics could help in designing an effective land-use policy for IGRB.

Anaerobic degradation of sulfate laden organics involves sulfide generation and release of soluble microbial products (SMP). Sulfide causes direct toxicity to microorganisms and precipitation of key metals. On the other hand, SMP helps in keeping higher soluble concentration of essential metals through complexation and alleviating sulfide toxicity. The role of SMP is well recognized in biological treatment of wastes but many issues are yet to be fully elucidated. The present paper discusses the effect of sulfide concentrations on SMP production and effect of complexation on soluble Fe, Ni, Zn and Co concentrations in laboratory scale uplflow anaerobic sludge blanket (UASB) reactor, anaerobic baffled reactor (ABR) and hybrid anaerobic baffled reactor (HABR) degrading synthetic sulfate laden organics at 35°C for varying operating conditions. Results indicate increased SMP concentration with increasing sulfide concentration and significantly higher measured Fe, Ni, Zn and Co concentrations due to complexation in all three systems. Soluble Fe 0.43–0.66 mg/L; Ni 0.29–0.4 mg/L; Zn 0.15–0.19 mg/L; and Co 0.13–0.29 mg/L appears to be adequate for stable process operation and performance.

Distillery spent-wash has very high organic content (75 000 to 125 000 mg/L chemical-oxygen demand [COD]), color, and contains difficult-to-biodegrade organic compounds. For example, anaerobic treatment of the distillery spent-wash used in this study resulted in 60% COD reduction and low color removal. Subsequent aerobic treatment of the anaerobic effluent resulted in enhancement of COD removal to 66%. In this paper, the effect of ozonation on various properties of the anaerobically treated distillery effluent, including the effect on its subsequent aerobic biodegradation, was investigated. Ozonation of the anaerobically treated distillery effluent at various ozone doses resulted in the reduction of total-organic carbon (TOC), COD, COD/TOC ratio, absorbance, color, and increase in the biochemical-oxygen demand (BOD)/COD ratio of the effluent. Further, ozonation of the anaerobically treated distillery effluent at an ozone dose of 2.08 mg/mg initial TOC and subsequent aerobic biodegradation resulted in 87.4% COD removal, as compared to 66% removal when ozonation was not used.

This paper presents a comparative assessment of the cost and quality of treatment of tannery wastewater in India by two common effluent treatment plants (CETPs) constructed for two tannery clusters, at Jajmau (Kanpur) and at Unnao in the state of Uttar Pradesh, India. The Jajmau plant is upflow anaerobic sludge blanket (UASB) process-based, while the Unnao plant is activated sludge process (ASP)-based. Investigations indicated that the ASP-based plant was superior in all respects. Total annualized costs, including capital and operation and maintenance costs, for the UASB and ASP plants were Rs. 4.24 million/million liters per day (MLD) and Rs. 3.36 million/MLD, respectively. Land requirements for the two CETPs were 1.4 hectares/MLD and 0.95 hectares/MLD, respectively. Moreover, the treated UASB effluent had higher biochemical and chemical oxygen demand (BOD/COD) and considerable amounts of other undesirable constituents, like chromium (Cr) and sulfide, as compared with the ASP effluent, which had lower BOD/COD and negligible concentration of sulfide and Cr. Sludge production from the UASB-based plant was also higher at 1.4 t/day/MLD, in comparison to the sludge production of 0.8 t/day/MLD for the ASP-based plant. Also, the entire sludge produced in the UASB-based plant was Cr-contaminated and, hence, hazardous, while only a small fraction of the sludge produced in the ASP-based plant was similarly contaminated. The results of this study are at variance with the conventional wisdom of the superiority of anaerobic processes for tannery waste-water treatment in tropical developing countries like India.

This paper presents correlation of methanogenic activity with performance of bench scale models of UASB, DSFF and USFF reactors at varying OLRs while maintaining EBHRT in the range of 0.80–1.10 d. At lower OLR, performance of the reactors appears to be similar. However, at higher OLR, the performance of DSFF and USFF reactors is fairly steady whereas UASB reactor shows poor performance in terms of methane production. This is in conformity with methanogenic activity test results. The results of AMA and TMA tests also reveal that at higher OLR, acetoclastic methanogens population decreases considerably in UASB reactor and a large fraction of methane is produced due to the activity of non-acetoclastic methanogens.

Insoluble (ISX) and soluble starch xanthate (SSX) were synthesized in the laboratory from corn starch, and were used for metal [Cd(II), Cu(II) and Cr(VI)] removal from aqueous systems. Results indicate that soluble as well as insoluble xanthate processes are capable of meeting various effluent disposal standards. Metal removal by both the processes is maximum in the pH range 4 to 5. Mechanism of Cu(I I)-xanthate and Cr(VI)-xanthate interaction is also discussed. From overall comparison of the two processes it appears that theinsoluble xanthate process has an edge over the solublexanthate process in terms of metal removal capacity, reliability and ease of operation, particularly for cadmium removal. However, soluble xanthate process appears to be relatively less expensive compared to insoluble xanthate.

This study is aimed at exploring strategies for mineralization of refractory compounds in distillery effluent by anaerobic biodegradation/ozonation/aerobic biodegradation. Treatment of distillery spent-wash used in this research by anaerobic-aerobic biodegradation resulted in overall COD removal of 70.8%. Ozonation of the anaerobically treated distillery spent-wash was carried out as-is (phase I experiments) and after pH reduction and removal of inorganic carbon (phase II experiments). Introduction of the ozonation step resulted in an increase in overall chemical oxygen demand (COD) removal, with the highest COD removals of greater than 95% obtained when an ozone dose of approximately 5.3 mg ozone absorbed/mg initial total organic carbon was used. The COD removal during phase II experiments was slightly superior compared with phase I experiments at similar ozone doses. Moreover, efficiency of ozone absorption from the gas phase into distillery spent-wash aliquots was considerably enhanced during phase II experiments.

This paper presents the finding of the investigation on the behaviour of metal removal and recovery using insoluble starch xanthate. It is hypothesized that metal-xanthate interaction is a net result of the two simultaneous reactions - (i) reversible complexation of metal with xanthate groups, and (ii) decomposition of the xanthates. The affinity, and also the selectivity sequence of metals for xanthate groups is postulated to follow the reverse order of metal-ethyl xanthate solubilities. Further decomposition of xanthates is viewed advantageous for metal recovery. Metal recovery is predicted to follow reverse order of metal-selectivity for xanthates. Results of the laboratory experiments carried out on insoluble starch (corn) xanthate are used to test the hypothesis. The selectivity of metals for ISX follows the sequence Hg(II)>Cu(II)>Cd(II)>Ni(II) which correlates with metal-ethyl xanthate Ksp values. The recovery of metals from metal-ISX sludge is attempted by using mineral acids (hydrochloric, sulfuric and nitric), oxidizing agents (chlorine solution and hydrogen peroxide) and eluting agent (EDTA). The results of metal removal and recovery are in accordance with the proposed hypothesis.

A galvanic cell using calcia stabilised zirconia as a solid electrolyte has been used to determine the temperature and heat of transformation of Fe2O3. The decomposition temperature of Fe2O3 as well as the Gibbs free energy of formation in the temperature range 873–1300° K have also been determined.