Simultaneous removal of nitrogen and organic carbon from swine wastewater using the pre-denitrification/nitrification process

Abstract

Wastewater from confined animal feeding operations (CAFOs) can interfere significantly with the natural nitrogen and phosphorus balance in the environment if not treated adequately prior to disposal. In this work, a modified Lutzak-Ettinger (MLE) consisting of sequential pre-denitrification/ nitrification was used to determine the effects of nutrient loading rates and hydraulic retention times (HRT) on total nitrogen (TN) and organic carbon (TOC) removal from swine wastewater. MLE reactor was continuously fed swine wastewater for over 205 days using different recycle ratios (Rr) and HRT. Higher TN and TOC removal efficiencies (90.7% and 96.1%, respectively) were obtained when recycling effluent from the nitrification tank (4.5:1) combined with effluent from the final clarifier (1:1). Removal efficiencies of 96% for TOC and 90% for TN were obtained for the maximum loading rates of 0.56 gTN L-1 d-1 and 2.15 g TOC L-1 d-1, respectively. TN and TOC removal rates were achieved with HRT in as little as 3.5 days. Overall, MLE was a robust bioprocess withstanding variations in wastewater physical-chemical composition and/or changes in operational conditions without significant impairment of N and TOC removal efficiencies.

The investigation of biological removal of nitrogen and phosphorous from domestic wastewater by inserting anaerobic/anoxic holding tank in the return sludge line of MLE-OSA modified system

“…There is therefore considerable impetus to explore and develop strategies and technologies for reducing excess sludge production in biological wastewater treatment processes [17,18]. (i) Endogenous metabolism,; (ii) uncoupling metabolism (iii) oxic settling-anaerobic [19,20]; (iv) alkaline heat treatment [20,21]; (v) oxidation of a part of produced sludge is done by such oxidizing materials as chlorine and ozone [22,23].…”

Efficiency studies of modified IFAS-OSA system upgraded by an anoxic sludge holding tank

“…Reducing the nutrients and excess sludge in biological processes can be done by various techniques and methods. Some of these techniques consist of oxic-settling-anaerobic (OSA) process 18 , 28 , oxidation of the sludge by chlorine and ozone 5 , 11 . OSA technique is also a suitable solution for enhancement organic matter and nutrient (N & P) pollutants removal which significantly reduces biological excess sludge.…”