Effects of operation mode on self-alkalization of high-load denitrifying reactor. (July 2015)

• Record Type: Journal Article
• Authors: Li, Wei; Li, Chenxu; Lin, Xiaoyu; Liu, Yan; Abbas, Ghulam; Zheng, Ping
• Is Part Of: Bioresource technology. Volume 187(2015)
• Page Start: 282
• Page End: 287
• Publication Date: 2015-07
• Subjects: Denitrification -- High-load reactor -- Operation mode -- Self-alkalization; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2015.03.063
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Self-alkalization intensity of high-load denitrifying reactors was investigated. Mechanism of self-alkalization under different operation modes was revealed. Decrease of HRT was optimal operation mode for high-load denitrifying reactor. Abstract: To study the alkalization issue and its potential effects on high-load denitrifying system, the effects of operation mode on self-alkalization of high-load denitrifying reactor were investigated. The results showed that both the increase of substrate concentration and decrease of hydraulic retention time (HRT) can induce notable self-alkalization of high-load denitrification reactor (with the nitrogen loading rate (NLR) higher than 25 kg N m −3 d −1 ). The effluent pH surpassed the 9.20 when the influent pH value was 7.0 ± 0.1. The self-alkalization of denitrification process originated from the nitrate reduction, while the methanol oxidation could alleviate the self-alkalization by neutralizing OH − and setting up a buffering system of HCO3 − /CO3 2− . At the same NLR, the self-alkalization induced by increase of substrate concentration was remarkably stronger than that induced by decrease of HRT. Keeping the nitrate concentration below inhibition concentration improved the performance of high-load reactor and alleviated the self-alkalization.