Improved sludge dewaterability by combining SDS pre-treatment conditioning with PDMDAAC flocculation

Abstract

Wastewater treatment generates considerable amounts of sludge. Reducing sludge volume by dewatering is an important part of many wastewater treatment processes. We investigated the effects of a combination of sodium dodecyl sulfate (SDS) and polydimethyldiallylammonium chloride (PDMDAAC) on anaerobically digested sludge dewaterability. Capillary suction time (CST) and specific resistance to filtration (SRF) were measured as indicators of sludge dewaterability. Extracellular polymeric substances (EPS) content, particle size, zeta potential, and bound water in sludge floc were also measured. We found that CST increased from 348.5 to 530.5 s as the SDS dosage increased. However, with a dose 0.03 g g-1 DS PDMDAAC only, SRF and CST were 3.78 × 10 12 m kg-1 and 79.2 s; with a combined dose of 0.025 g g-1 DS SDS and 0.03 g g-1 DS PDMDAAC, SRF and CST decreased to 3.21 × 10 12 m kg-1 and 68.7 s. These results indicate that above a certain dose, SDS reduces sludge dewaterability and that an optimum dose of SDS in sludge pre-treatment would improve subsequent PDMDAAC conditioning. Sludge conditioned with a combination of SDS and PDMDAAC increases dewaterability more than conditioned with SDS only or PDMDAAC only. Freeing EPS-bound water with SDS followed by re-flocculation using PDMDAAC gave improvement in sludge dewaterability.

Effect of substitution groups on the homopolymerization activity of methyl aryl diallyl ammonium chloride

“…With a wide range of prospective applications, particularly in the domains of petrochemicals, water treatment, personal care, biomedicine, and electrochemical materials, its homopolymers and copolymers occupy a highly special and significant position for study. [1][2][3][4][5][6][7][8][9] There is still much room for improvement in their applicable applications, particularly those involving aromatic lipophilic applications like petroleum extraction and wastewater treatment for printing and dyeing, as DMDAAC-based polymers frequently struggle with weak affinities to aliphatic substances. Currently, there are a large number of applications for lipophilicity based on aromatic rings.…”

“…The characteristic monomer of diallyl quaternary ammonium salt cationic polymers, a family of water‐soluble organic polymers with significant features, is dimethyl diallyl ammonium chloride (DMDAAC). With a wide range of prospective applications, particularly in the domains of petrochemicals, water treatment, personal care, biomedicine, and electrochemical materials, its homopolymers and copolymers occupy a highly special and significant position for study 1–9 . There is still much room for improvement in their applicable applications, particularly those involving aromatic lipophilic applications like petroleum extraction and wastewater treatment for printing and dyeing, as DMDAAC‐based polymers frequently struggle with weak affinities to aliphatic substances.…”

“…I G U R E 3 The optimized configurations of methyl aryl diallyl ammonium chloride monomer and their transition state at the B3LYP/6-31G* level. Nitrogen atom (4), Chlorine atom(25,26), carbon atom(1,2,3,5,6,7,8,9), and hydrogen atoms(remainder).was apparent that for both DMDAAC, DAMBAC, DAMMBAC, and DAMNBAC monomer molecules, the H atoms were positively charged, while the negative charges were concentrated on the Cl, N, O, and C atoms. Throughout the data on the charge distributions on the allyl carbon-carbon double bond of the four monomers, it was clear that the introduction of the aryl groups made the charge distributions gap on the double bonds larger and caused a decrease in stability.…”

Effect of Substituents on the Homopolymerization Activity of Methyl Alkyl Diallyl Ammonium Chloride

“…Water-soluble cationic polyelectrolytes are a kind of important polymers, among which the study of homopolymers and copolymers of dimethyl diallyl ammonium chloride (DMDAAC) occupies a very unique and important position. They have been widely used in water treatment, petroleum exploitation, textile printing, dyeing, the daily chemical industry, the pharmaceutical chemical industry, electrochemical materials, electronic sensors, and other fields [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. In addition, to improve the relative molecular weight of DMDAAC-based polymers to form products with serial cationicity and relative molecular weight, in recent years, it was found that the group structure of quaternary ammonium nitrogen is directly related to its mode of action and efficiency at the phase interface, especially in some lipophilic application fields.…”