Peat as Substrate for Small-Scale Constructed Wetlands Polishing Secondary Effluents from Municipal Wastewater Treatment Plant

Meng Jin,Pascale Champagne,Rachel Mcconnell,Geof Hall,Jacob Carlos

doi:10.3390/w9120928

Abstract

With the recent development of constructed wetland technology, it has become a mainstream treatment technology for the mitigation of a variety of wastewaters. This study reports on the treatment performance and pH attenuation capacity of three different configurations of small-scale on-site surface flow constructed wetlands (SFCW): T1 (Peat + Typha latifolia), T2 (T. latifolia alone), and T3 (Peat alone) treating secondary effluent from the Amherstview Water Pollution Control Plant (WPCP) for two treatment periods (start-up period and operational period). The aim of this study was to compare the nutrients removal efficiencies between the different treatments, as well as to evaluate the effects of substrate and vegetation on the wetland system. For a hydraulic retention time of 2.5 days, the results showed that all treatment systems could attenuate the pH level during both the start-up and operational periods, while significant nutrient removal performance could only be observed during the operational period. Peat was noted to be a better SFCW substrate in promoting the removal of nitrate (NO3-N), total nitrogen (TN), and phosphorus. The addition of T. latifolia further enhanced NO3-N and TN removal efficiencies, but employing T. latifolia alone did not yield effluents that could meet the regulatory discharge limit (1.0 mg/L) for phosphorus.

Highlights

IntroductionConstructed wetlands are considered to be a sustainable passive wastewater treatment technology, and have been used to treat a variety of wastewaters for decades, including domestic or municipal wastewater [1,2], industrial wastewater [3,4], agricultural [5,6,7], acid mine drainage [8], river and lake water [9,10,11], groundwater [12], landfill leachate [13,14,15], highway [16] and airport [17] runoff.They take advantage of many of the same processes that occur in natural wetlands, but do so in a more controlled or engineered system [18]
Surface flow constructed wetlands (SFCW) represent an older and less sophisticated configuration, they remain an effective treatment approach. Despite their lower treatment efficiencies compared to subsurface flow constructed wetlands (SSFCW), the lower construction cost and maintenance requirements associated with surface flow constructed wetlands (SFCW) are desirable for smaller and more rural
The objective of this paper was to assess the effects of peat and T. latifolia on the attenuation of pH and treatment of a municipal secondary effluents in three small-scale on-site SFCW reactors at the Amherstview Water Pollution Control Plant (WPCP) located on the northern shore of Lake

Summary

Introduction

Constructed wetlands are considered to be a sustainable passive wastewater treatment technology, and have been used to treat a variety of wastewaters for decades, including domestic or municipal wastewater [1,2], industrial wastewater [3,4], agricultural [5,6,7], acid mine drainage [8], river and lake water [9,10,11], groundwater [12], landfill leachate [13,14,15], highway [16] and airport [17] runoff.They take advantage of many of the same processes that occur in natural wetlands, but do so in a more controlled or engineered system [18]. Constructed wetlands are considered to be a sustainable passive wastewater treatment technology, and have been used to treat a variety of wastewaters for decades, including domestic or municipal wastewater [1,2], industrial wastewater [3,4], agricultural [5,6,7], acid mine drainage [8], river and lake water [9,10,11], groundwater [12], landfill leachate [13,14,15], highway [16] and airport [17] runoff. Despite their lower treatment efficiencies compared to SSFCW, the lower construction cost and maintenance requirements associated with SFCW are desirable for smaller and more rural

Objectives

Methods

Conclusion