Development of a Novel Helical-Ribbon Mixer Dryer for Conversion of Rural Slaughterhouse Wastes to an Organic Fertilizer and Implications in the Rural Circular Economy

Organic wastes of rural slaughterhouses in developing countries comprise of blood and undigested rumen contents harboring infectious microbial pathogens and having impermissible BOD5 and COD values. Previously we demonstrated valorization of blood and rumen contents through drying and conversion to an efficacious organic fertilizer which was free from infectious pathogens and heavy metals. Here we describe fabrication of a novel helical-ribbon mixer dryer for transition from the current small-scale household cooking to equipment-driven sustainable production. Blood and rumen digesta mixed in a 3:1 ratio, having initial moisture of 85%, were dried at 90–110 °C for 3–4 h to attain 15.6% final moisture-containing organic fertilizer. Energy consumption and moisture extraction rate were 49.4 MJ per batch and 18.9 kg h−1 respectively. Using this method, small abattoir owners could emerge as multi-product producers to enhance earnings while farmers could source the fertilizer locally for organic farming. The two activities can be complementary to each other and become a sustainable circular economy model. We applied a spreadsheet-based model for calculation of cash flow, breakeven point and conducted financial cost–benefit analysis on the projected operation of the dryer. Fertilizer production parallel with the meat trade should be profitable for slaughterhouse owners and farmers apart from generating local employment opportunities

WATER CLARITY ASSESSMENT FOR A REGIONAL LAKE USING LANDSAT OPERATIONAL

Not AvailableLandsat operational land imager (OLI) data and consequent laboratory measurements were used to predict water clarity for an inland lake within the East Kolkata Wetland, India (a Ramsar site). Total suspended sediment (TSS) and turbidity was considered as responsible parameters for assessment of lake clarity. The most suitable band ratio was identified by performing Pearson correlation analysis between water clarity concentrations and possible OLI band and band ratios from the ‘study points’. The OLI 4 band (636-673 nm) showed the best ‘r’ value, 0.96 and 0.89 in case of TSS and turbidity respectively. The two separate prediction models (using non-transformed and logarithmically transformed water clarity data) was developed by applying regression analysis between the band reflectance value of OLI4 and water clarity concentrations of the study points. The band reflectance value of the ‘validation points’ was given as input in the prediction model and model predicted dataset was considered as predicted water clarity parameters. The model predicted dataset exhibit lower standard error of estimates (SEE) with contemporaneous in situ measurements. The validation of the multi-temporal competence of the best models indicated that it is feasible to apply the linear regression model using OLI 4 band to estimate water clarity concentrations across the seasons in Nalban Lake without any in situ data. The water clarity mapping of the lake was then developed using the predicted dataset. This empirical study showed that Landsat 8 OLI imagery could be effectively applied for the mapping of TSS and turbidity for inland lakes.Not Availabl

Organic Cultivation of Tomato in India with Recycled Slaughterhouse Wastes: Evaluation of Fertilizer and Fruit Safety

Environmental and health safety of recycled slaughterhouse wastes-derived fertilizer and the produce obtained through its application is not well understood. Waste bovine blood and rumen digesta were mixed, cooked and sun-dried to obtain bovine-blood-and-rumen-digesta-mixture (BBRDM, NPK 30.36:1:5.75). 1.26 ± 0.18 log CFU mL−1 fecal coliforms were recovered in BBRDM. E. coli O157:H7, Mycobacteria, Clostridium sp., Salmonella sp., Bacillus sp. and Brucella sp. were absent. No re-growth of pathogens was observed after 60 days storage in sealed bags and in the open. However, prions and viruses were not evaluated. Heavy metals (Pb, Cr, Cd, Cu, Zn, As, Ni, Mn) concentrations in BBRDM were within internationally permissible limits. BBRDM was applied for field cultivation of tomato during 2012–2013 and 2013–2014. Lycopene and nitrate contents of BBRDM-grown tomatoes were higher than Diammonium phosphate (DAP) + potash-grown tomatoes because BBRDM supplied 2.5 times more the amount of nitrogen than DAP (NPK 18:46:0) + potash (NPK 0:0:44). Heavy metals and nitrate/nitrite concentrations in tomatoes were within internationally acceptable limits. BBRDM-grown tomatoes showed no mutagenic activity in the Ames test. Sub-acute toxicity tests on Wistar rats fed with BBRDM-grown tomatoes did not show adverse clinical picture. Thus, no immediate environmental or health risks associated with BBRDM and the tomatoes produced were identified

Isolation of indigenous <i>Staphylococcus sciuri</i> from chromium-contaminated paddy field and its application for reduction of Cr(VI) in rice plants cultivated in pots

<p>Accumulation of Cr(VI) in rice seeds cultivated in Cr-contaminated soil of the Sundarbans (India) is an environmental problem. Cr(VI) concentration in this soil was 6.2 ± 0.3 mg/kg, whereas total chromium was 32.04 ± 1.60 mg/kg. A Cr(VI)-removing bacterium isolated from Cr-contaminated paddy field soil of Sundarbans was identified as <i>Staphylococcus sciuri</i>. Enrichment culture of <i>S. sciuri</i> was applied to pot cultivation of rice in Cr-contaminated soil. After 8 weeks, 71 ± 3% Cr(VI) (final concentration 2.15 ± 0.01 mg/kg) and 65 ± 2% total Cr removal (end concentration 11.3 ± 0.5 mg/kg) were attained in bacterium-treated soils. Growth parameters indicated healthy development of plants cultivated in bacterium-treated soils that was not observed in control plants. Total Cr removal attained in rice seeds of plants cultivated in bacterium-treated soils compared with control rice seeds was 78 ± 4%. Total Cr concentration in test seeds was 0.72 ± 0.05 mg/kg (World Health Organization [WHO] permissible limit: 1.30 mg/kg), whereas the same in control seeds was 3.27 ± 0.16 mg/kg. Cr(VI) reduction achieved in rice seeds cultivated in bacterium-treated soil compared with control rice seeds was 95 ± 5%. Cr(VI) concentration in rice seeds cultivated in treated soil was 0.050 ± 0.003 mg/kg, whereas the same in untreated control was 0.93 ± 0.05 mg/kg. Successful paddy field soil bioremediation by any <i>Staphylococcus</i> species was demonstrated for the first time.</p