Screening of Bioflocculant and Preliminary Application to Treatment of Tannery Wastewater

Abstract

ABSTRACT:In this study, three strains of bacteria Bacillus cereus CZ1001, B. subtilis CZ1002, and B. fusiformis CZ1003 were inoculated into four different kinds of culture medium. After growth, the supernatants were collected and added to kaolin suspensions to determine whether these Bacillus strains produced flocs that could be filtered out. Efficient bacteria and media were then selected to produce bioflocculants which were subsequently extracted using pre-cooled ethanol. After freeze drying, the flocculants were used to treat tannery wastewater. Results showed cultures of B. subtilis CZ1002 growing in media No. 4, B. cereus CZ1001 growing in media No.

Microbial Flocculants as an Alternative to Synthetic Polymers for Wastewater Treatment: A Review

“…For example, Tang et al (2014) reported a flocculant from Paenibacillus mucilaginosus with removal efficiencies of 70-75.2% and 81.5-88%, respectively, for COD and SS from paper mill wastewater. The same bioflocculant allowed the removal of 88.8-92% of SS from biological factory wastewater, with 83.2-86.9% reduction of COD [73]. Similar work was conducted with garbage incineration plant wastewater (pH 6.08), giving a COD ranging from 59.7% to 60.7% and SS removal in the range of 68-69.8%.…”

“…The use of microbial flocculants as flocculating substances in various municipal and industrial wastewater was proven to cause a significant reduction in levels of SS, turbidity, and COD, as indicated in Table 4 [25,27,57,60,[69][70][71][72][73]. 1 Chemical oxygen demand, 2 Total Kjeldahl nitrogen, 3 Total phosphorus, 4 total solids, 5 Suspended solids, 6 total nitrogen.…”

Optimization of Microbial Flocculant-Producing Medium for Bacillus subtilis

“…The initial bioflocculant-producing medium contained the following: 30 g glucose, 8 g yeast extract, 2 g dipotassium hydrogen phosphate, 0.25 g magnesium sulfate, 10 g sodium glutamate, distilled water to 1000 mL (pH 7.5) [3].…”

“…where E is the flocculation rate (%), A is the absorbance of the kaolin suspension processed by the sample, and B is the absorbance of the control (blank kaolin suspension) [3].…”

“…These features make them an ideal substitute for inorganic and organic synthesized coagulants and flocculants, and they have great potential for use in a range of applications [1,2]. Early experiments by our group found that one microbial flocculant produced by Bacillus subtilis was able to remove chemical oxygen demand (COD), color, ammonia, and total nitrogen from tannery wastewater [3,4]. However, the flocculation activity must be improved for its true potential to be realized.…”