Co-digestion of cassava starch wastewater with buffalo dung for bio-hydrogen production

ABSTRACT The operation of drip lateral lines is affected by the topography of the irrigated area and represent, depending on the type of water applied, changes in the discharge characteristics of the emitters. The research had as objective to evaluate the hydraulic performance of built-in labyrinth drippers, non-pressure compensating, with different waters and slopes of the lateral lines. The experiment was carried out on a test bench and consisted of a randomized block design with split-plots: first factor with four types of water, representing the plots: clean water, water with fertilizers, cassava starch wastewater and poultry slaughterhouse wastewater; second factor with slopes of the lateral line, constituting the sub-plots: upslope, level and downslope. The experimental statistics consisted of analysis of variance with subsequent simple-effect analysis and Tukey test at 0.05 probability level to compare the means of dripper flow rates. Quality control statistics was performed using Shewhart’s control charts with interpretations based on upper and lower control limits, as well as non-random pattern recognition. Waters of inferior quality modified the flow rates of the tested drippers regardless of the variation of internal pressure caused by the slope of the lateral line. Water with fertilizer (300 mg L-1) obtained the best conditions of temporal irrigation quality verified by the control charts. Irrigation with poultry slaughterhouse wastewater obtained the same flow rates in all slopes. Cassava starch wastewater caused the lowest flow rates among all the waters.

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Dolomitic limestone as an alkalizing agent for treating cassava starch wastewater in an anaerobic reactor

Revista CERES ◽

10.1590/0034-737x201865050002 ◽

2018 ◽

Vol 65 (5) ◽

pp. 388-394

Author(s):

Denise Palma ◽

Julia Piechontcoski Fernandes ◽

Marney Pascoli Cereda ◽

Simone Damasceno Gomes

Keyword(s):

Oxygen Demand ◽

Cassava Starch ◽

Total Alkalinity ◽

Dolomitic Limestone ◽

Organic Loading ◽

Reactor Operation ◽

Anaerobic Reactor ◽

Loading Rates ◽

Volatile Acidity ◽

Starch Wastewater

ABSTRACT Cassava processing wastewater has a low Volatile Acidity/Total Alkalinity ratio, low buffering capacity and became quickly acidified. In this trial, dolomitic limestone was used as an alkalizing agent in an anaerobic reactor to treat cassava starch wastewater. The dolomitic limestone contained 27% CaO and 23% MgO and granulometry between 24.5 and 38.1 mm. The average Chemical Oxygen Demand of the wastewater was 13331.30 mgO2 L-1, the organic loading rates (OLR) ranged from 1.23 to 16.43 gCOD L-1 d-1 and the hydraulic retention times ranged from 10.00 to 0.80 days. The results showed that the calcium concentrations increased in the reactor effluent and the magnesium concentrations decreased as the organic loading rates increased. Ca2+ and Mg2+ concentrations were approximately 5,000 and 5.05 times greater in the sludge than in the inoculum, respectively. The average pH, Total alcalinity, Volatile Acidity and Volatile Acidity/ Total alcalinity values were 6.69, 882.54 mgCaCO3 L-1, 221.55 mgCH3COOH L-1 and 0.22, respectively. The loss of limestone mass corresponded to only 2.51% of the initial mass, after 134 days of anaerobic reactor operation. Finally, it was concluded that the limestone effectively controlled acidification through the alkalinity increased in the system.

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