Effectiveness of Mushroom (Pleurotus Pulmonarius) Waste as Natural Coagulant for Kaolin Synthetic Water via Coagulation-Flocculation Process

Coagulation-flocculation process is a widely used method in water treatment. In this study, mushroom waste was selected as natural coagulant to treat kaolin synthetic water via coagulation-flocculation process. Rotten mushroom and mushroom spent were evaluated separately. Functional group of mushroom wastes were analyzed using Fourier Transform Infrared Spectroscopy. Optimum dosage and pH of mushroom wastes and aluminium sulphate in kaolin synthetic water treatment were examined through jar testing. A comparative study on the effectiveness of mushroom wastes and aluminium sulphate in kaolin synthetic water treatment was evaluated in terms of turbidity removal percentage and sludge volume index. Results obtained from jar testing show rotten mushroom and mushroom spent achieved turbidity removal efficiency of 99.73% and 99.25% respectively at optimal pH of 4 and optimal dosage of 5 mg/L whereas 99.91% of turbidity was eliminated by alum under optimum condition of pH 9 and dosage 25 mg/L. Under optimized condition, sludge volume index value obtained by rotten mushroom, mushroom spent and alum were 37.38 mL/g, 40.34 mL/g and 51.58 mL/g respectively. Overall, the finding indicated that mushroom waste could be a potential alternative to chemical coagulant since they are environmentally friendly, effective in turbidity removal, producing less sludge and pH independent.

Batch electrochemical coagulation of real textile wastewater using Cu-SS and SS-Cu electrode combinations and its settleability aspects

Copper and stainless steel electrodes were used in batch electrochemical coagulation (BECC) for the treatment of real textile wastewater using 16 electrode combinations. Out of 16 Cu-SS and SS-Cu combinations (eight combinations each), only 4SS and 3SS-1Cu electrodes operated at cell voltage of 18 V and current density of 180 A/m2 gave maximum color and chemical oxygen demand (COD) removals. The COD removal was observed to be 89.37% for 4SS and 72.34% for 3SS 1Cu electrodes from CODo 3,012 mg/L. Color removal was 97% and 98% from its initial value of 1,000 Pt-Co unit for 4SS and 3SS-1Cu combinations. Water quality parameters like total dissolved solids, chloride, nitrate, phosphate, and sulphate reduced from their initial values while using all 4SS and 3SS-1Cu electrode arrangements. Other control factors exercised for optimal operations were ECC floc settling pattern and sludge volume index (SVI). SVI values were found to be <100 mL/g for both electrode combinations.

INFLUENCE OF STATIC MIXER ON THE FORMATION OF BIOGRANULES

Present study aimed at evaluating the formation of biogranules using sequencing batch reactors (SBRs) in treating textile wastewater under the influence of static mixer. Three sets of experiment were run with different superficial air velocity (SAV) of 0.5, 1.4 and 2.1 cms-1, each set consisting of two SBR one with and one without static mixer. The developed biogranules in reactors with static mixer (R1M, R2M and R3M) showed good results after approximately 70 days. The biomass in the reactor reached mix liquor suspended solid (MLSS) of 5.75 gL-1 with sludge volume index (SVI) of 107.4 mLg-1 and settling velocity (SV) of 70.3 mh-1 in R1M; MLSS of 7.18 gL-1 with SVI of 29.5 mLg-1 and SV of 80.4 mh-1 for R2M and MLSS of 7.38 gL-1 with SVI of 36.3 mLg-1 and SV of 74.2 mh-1 for R3M. The use of static mixer has contributed to biogranules development with good settling properties.

PRELIMINARY STUDIES ON THE INFLUENCE OF NEGATIVE PRESSURE ON ACTIVATED SLUDGE FLOCS

A sludge from municipal wastewater plant operated for biological contaminant removal was exposed to three different negative pressures (-200, -500 and -800 hPa) for three different duration times (30 second, 1 and 2 minutes). Sludge volume index, shear sensitivity of the sludge and activated sludge floc characteristic was the object of the study before and after negative pressure treatment. After the treatment the sludge settled better independently on the pressure value and duration time. The shear sensitivity changed the most when the pressure exposure of -800 hPa was 1 minute and longer. The flocs structure was more open after negative pressur and larger part of activated sludge was comprised by large flocs.