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Knowledge of the distributions and mass balances of C, N, and P during anaerobic digestion (AD) processes serves several purposes; for instance, these values can be used to obtain reliable quantitative information on the fate of C, N, and P after AD, to understand carbon and nutrient balances, and to evaluate the contribution of AD processes to elemental cycles. In this paper, C, N, and P contents in the gas, liquid and solid phases were investigated for seven different substrates: corn straw, rice straw, wheat straw, swine manure from pigs fed feedstuff or foodstuff, cattle manure, and chicken manure. The conversion efficiency of C in a substrate into methane was found to be highest in swine manure from pigs fed foodstuff (15.8%), and greater liquid and solid stream nutrient levels were found in the swine manures and chicken manure than in the cattle manure and straws. The mass balances of C, N and P for each different substrate were distinct, but all balances were close to 100% in this study. Further study revealed that CH 4 yields and substrate lignin fitted a linear negative relationship well, and the COD/TOC, NH 4 + -N and TP concentrations in the supernatant had positive linear relationships with the proteins, TAN/proteins and potassium of substrates, respectively. [ABSTRACT FROM AUTHOR]

Selective adsorption of phosphate from a complex solution is the key step for phosphate recovery from industrial wastewater. Despite recent research progress, phosphate removal with high selectivity has been found challenging, largely due to the complicated dynamic adsorption behavior of other competing anions in the aqueous waste solution. In the present study, pyromellitic acid (PMA) intercalated layered double hydroxides ([Zn 0.68 Al 0.32 (OH) 2 ](PMA) 0.08 ·0.3H 2 O, denoted as Zn 2 Al-PMA-LDHs) were synthesized and shown to possess a high selectivity (97.41% at pH 7.0) towards phosphate in a hybrid solution containing H 2 PO 4 − , SO 4 2− , CO 3 2− , NO 3 − and Cl − . In addition, benzoic acid (BA), terephthalic acid (TA) and trimesic acid (TMA) intercalated LDHs also showed similar adsorption performance. The hydrogen bond between hydroxyl group of phosphate as the donor and oxygen of dissociated aromatic carboxyl group as the acceptor was found to play a key role in phosphate adsorption, as suggested by FT-IR and XPS analysis. This work not only presented a well performed material but also a useful method for better design of efficient LDHs for selective phosphate adsorption. [ABSTRACT FROM AUTHOR]