The Effect of the Hydraulic Retention Time on the Performance of an Ecological Wastewater Treatment System: An Anaerobic Filter with a Constructed Wetland

Abstract

This work assesses the performance of a municipal pilot wastewater treatment system employing an up-flow anaerobic filter (UAF) followed by a horizontal subsurface constructed wetland (HSSCW). This pilot scale demonstration project was implemented in a zone with subtropical climate in order to protect Lake Chapala from wastewater loads that are discharged by small communities in the Lake's vicinity. The filters were filled with tezontle as the media for biofilm support and the HSSCW was planted with two ornamental plants species, Canna hybrids and Strelitzia reginae. The experiment evaluated three hydraulic retention times (HRT) of 18, 28 and 38 h in the UAF, which corresponds to two, three and four days in HSSCW over 66 weeks. The mean efficiencies found for the complete system were 80% and 90% of BOD, 80% and 86% of COD, 30% and 33% of Ntot and between 24% and 44% of Ptot. It was possible to remove almost 80% of organic matter in 18 h in the UAF while the HSSCW reached 30% of removal for Ntot in a HRT of three days. As expected, the UAF was responsible for removing most of the organic matter and the HSSCW removed most of the nitrogen. OPEN ACCESSWater 2015, 7 1150

High-Strength Domestic Wastewater Treatment and Reuse with Onsite Passive Methods

“…The design of the present treatment system is based on experience gained in a demonstrative pilot plant installed previously in Chapala, Jalisco, Mexico [29]. In the sewage pipes, black and gray water are mixed together with discharges of non-hazardous liquid wastes generated in laboratories and food processing pilot plants.…”

“…The up-flow anaerobic filter (UAF) is divided into two chambers, the function of the first one is to receive and distribute the wastewater from the bottom into a wider second chamber filled with a volcanic porous rock, known as lava rock, which is commonly called "tezontle" in Mexico [29]. The second chamber is the anaerobic up-flow chamber where the wastewater flows from the bottom to the top of the chamber through the porous media created with the use of tezontle.…”

“…On the other hand, in many countries, and especially in the tropics and subtropics, local plants including ornamental species are used for HF CWs such as Zantedeschia aethiopica (giant white arum lily), Strelitzia reginae (crane flower, bird of paradise), Anthurium andraenum (flamingo flower), and Agapanthus africanus (agapanthus) [27]. Based on a search of the literature and in previous experience, it was concluded that it is possible to use ornamental plants in constructed wetlands without reducing the efficiency of the treatment system [28][29][30][31].…”

Domestic Wastewater Depuration Using a Horizontal Subsurface Flow Constructed Wetland and Theoretical Surface Optimization: A Case Study under Dry Mediterranean Climate

“…As the CW surface is related to contaminant abatement efficiency, it is necessary to find the optimal design in order to maximize abatement efficiency, while keeping the area to a minimum. In this respect, hydraulic retention time (HRT), reference evapotranspiration (ET 0 ) and temperature (T) are the parameters that most determine the efficiency [11,20].…”

Applicability of Constructed Wetlands for Water Quality Improvement in a Tea Estate Catchment: The Pussellawa Case Study

“…The regression analysis confirmed these observations, with a strong linear correlation between MLRs and MRRs for BOD5, TSS, FC, TC, and NH4 + -N, of over 0.9 in both wetland units; a moderate correlation for NO3 − -N (R 2 = 0.743) in the HSSF wetland unit; and a weak relationship for NO3 − -N in the VSSF wetland unit (R 2 = 0.25). On the other hand, REs were negatively impacted by increasing HLRs for all measurements, except for NH4 + -N, which was positively impacted by increasing HLRs in both the VSSF and HSSF units, though such enhanced NH4 + -N REs BOD 5 removal mechanisms in CWs include adsorption, sedimentation, filtration, and microbial degradation [25]. From Figure 7a, even though it was noted that there are slight differences in BOD 5 removal between the VSSF and HSSF wetland units, statistical analysis showed there was no significant treatment difference between the two systems (p > 0.05).…”