Technology of anaerobic-aerobic purification of wastewater from nitrogen compounds after obtaining biogas

Natalia Golub,Dariya Voiyevoda,Olexandr Kozlovets

doi:10.15587/1729-4061.2016.72336

Abstract

The technological parameters, by which the concentration of nitrogen containing compounds can be reduced to 75 % in the process of purification of the waste water from methane tanks after the process of the anaerobic fermentation of the poultry remainder were determined. The influence of the cosubstrate structure on the change of the concentration of nitrogen compounds in wastewater in the process of obtaining biogas from the remainder was shown. The cosubstrate, which contains more lignin, contributes to double increase in the content of ammonium ions, in relation to the substrates, the content of lignin in which does not exceed 25 %; besides, it does not increase the content of organic compounds in wastewater. The lower content of lignin leads to the fact that the content of organic substances in wastewater is 70 % higher. The technological parameters (time of hydraulic retention, the ratio of the flows in the process of wastewater purification) of the anaerobicaerobic process of wastewater purification were defined. The obtained laboratory results provide an opportunity to develop the technology of the anaerobic fermentation of the wastes of livestock breeding industry with wastewater reusing in the technological process of anaerobic waste processing. This technology is attractive in cases when in the process of fermentation it is necessary to add water for bringing the content of the methane tank to the optimum humidity; the fermentation of poultry breeding wastes is a good example of such use.

Highlights

In the anaerobic utilization of the waste of livestock breeding, especially of poultry breeding, there is a problem of wastewater utilizing after the separation of the solid phase in the separator at the outlet of a methane tank [1]
The concentration of ammonium ions and СOD in the wastewater after the process of methanogenesis from the remainder is influenced by the component composition of the used co-substrate
Co-substrate, which has higher lignin content, contributes to increasing ammonium ions content twice in relation to the substrates, the lignin content of which does not exceed 25 %; besides, it does not increase the content of organic compounds in wastewater

Summary

Introduction

In the anaerobic utilization of the waste of livestock breeding, especially of poultry breeding, there is a problem of wastewater utilizing after the separation of the solid phase in the separator at the outlet of a methane tank [1]. In the course of processing the waste of the biogas production, while loading the methane tank with 5 % of the dry substance at the volume of a methane tank of 3000 m3 and with keeping raw materials there for 24 days, 90 m3/day of wastewater are produced [2]. Wastewaters are highly concentrated and have a high content of nitrogen and ammonium nitrogen (up to 180 mg/dm3), which complicates the technology of their purification and makes their dumping into natural bodies of water impossible. The development of the technological solutions of the purification of the wastewater with the high concentration of ammonium ions is an urgent problem

Analysis of scientific literature and the problem statement

The purpose and objectives of the study

Findings

Conclusions