Feasibility of a semi-batch vertical-flow wetland for onsite residential graywater treatment

Abstract

Available online xxx Keywords: Graywater treatment Vertical flow wetland Nonpotable water reuse Biofilm Semi-batch A B S T R A C TThe technical feasibility of graywater treatment, via a semi-batch vertical flow wetland (SB-VFW), was evaluated at a single family home for aboveground water reuse. Graywater treatment was achieved to a quality level that was well within the regulatory compliance limits (e.g., with respect to biochemical oxygen demand (BOD), total suspended solids (TSS) and turbidity) for above ground reuse. System performance over the course of a five-month field study demonstrated that the necessary treatment time was typically $3 h for a 300 L batch. The SB-VFW operated in a stable manner owing to the use of a coconut soil substitute that has high hydraulic conductivity and also enabled avoidance of clogging due to excess biofilm growth. The latter was made possible through the use of a bio-based laundry (BBL) detergent which had a lower organic content relative to conventional laundry detergents. The system was able to return to normal operation even after detergent shock loads. Results of the present study are encouraging and suggest that residential level graywater treatment is technically feasible and can thus potentially expand the range of possible water reuse applications.

Role of Wetland Plants and Use of Ornamental Flowering Plants in Constructed Wetlands for Wastewater Treatment: A Review

“…One of the advantages of using OFP in CWs is the significant reduction of nutrient contamination (20-35%; Figure 2) comparing when CWs unplanted, representing an economical and sustainable alternative to decentralization practices; CWs are less expensive than commercial systems and are easier to build and operate [16,72]. Furthermore, by using plants with commercial value, the resources invested in the design, construction and maintenance of the system can be recovered in the profits of retail sales, without impeding the removal of pollutants of the system.…”

“…The type of vegetation used are plants from natural wetlands, including Cyperus papyrus, Phragmites australis, Typha and Scirpus spp., which have been evaluated for their positive effects on treatment efficiency for nutrient and organic compounds around the globe [8,9,11]. In Americas, such species are typical in CWs, and are found mainly in the United States, where the technology has been used extensively and is implemented in different rural and urban zones [12][13][14][15][16]. In recent studies (15 years ago), the goal of CW studies involved an investigation into the use of herbaceous perennial ornamental plants in CWs, including the use of species with different colored flowers to make the systems more esthetic, and therefore making it more probable for adoption and replication.…”

Wetlands for Wastewater Treatment

“…Wu, Fan, Zhang, Ngo, Guo, Hu et al (2015) revealed that intermittent aeration was an appropriate operation strategy for enhancing organic pollutants and nitrogen removal in VFCW. Another study (Yu, Bill et al, 2015) showed a semi-batch VFCW could reduce the pollutants (BOD, TSS, and turbidity) level to below regulatory limits, thus the semi-batch VFCW design was feasible for onsite residential greywater treatment. Osmanaj et al (2015) discussed the potential of CWs for wastewater treatment in rural areas in Kosovo with combination of 1 st stage VFCW and 2 nd stage HFCW.…”

Cost–Benefit Analysis of Onsite Residential Graywater Recycling: A Case Study on the City of Los Angeles

“…(Friedler et al 2005), but impedes the adoption of onsite graywater treatment in lowdensity residential housing such as single-family homes. More recent work by Yu et al (2015) showed that relatively short breakeven periods are achievable using a wetland treatment system for above-ground nonpotable graywater recycling in a single-family home. Even shorter payback periods and broader economic implications of onsite graywater reuse may be possible in cities in arid regions that are facing water scarcity and have limited capability for reusing centralized recycled water due to the lack of a distribution system.…”