Swine Wastewater Treatment in Constructed Wetland Systems: Hydraulic and Kinetic Modeling

Abstract

The use of constructed wetland systems (CWS) is presented as an alternative for the treatment of effluents since these have reduced implementation costs and relative ease of operation. The present research was undertaken to evaluate to study the hydrodynamic and the fitting of first-order mathematical kinetic models for the removal of pollutants in CWS. Three CWS were built, using expanded clay as filter support: one cultivated with Polygonum punctatum (CWSw), another cultivated with Chrysopogon zizanioides (CWSV), and a control unit (CWSc). The actual retention time was 3.12 days in the CWSc, whereas, in the CWSw and CWSv, we observed values of 4.14 and 4.11 days, respectively. The dispersion values were high in all CWS. The values of chemical oxygen demand (COD) across the length of the CWS were used to fit the kinetic models that describe the first-order decay of organic matter over the CWS. The models that showed a better fit to the experimental data were the plug-flow with residual concentration, the continuous stirred tank reactor, and Shepherd’s models.

Description of a Fe/Al Electrocoagulation Method Powered by a Photovoltaic System, for the (Pre-)Treatment of Municipal Wastewater of a Small Community in Northern Greece

“…In this case, the cylindrical reactor was attached to the Fe electrodes, NaCl (3.0 g) was added as before and a current of 300 mA was applied. Before the beginning of each experiment, wastewater (300 mL) pH was adjusted to the desirable value (3)(4)(5)(6)(7)(8)(9)(10)(11) with the use of 1 M H 2 SO 4 or 1 M NaOH. COD was measured as described before.…”

“…The 10th biennial EU report on the implementation of the Directive, which was published in 2020, highlights the lack of full compliance throughout EU, with 6% of the MWW collected not sufficiently treated to meet secondary treatment standards, and 8% of the MWW collected not meeting more stringent treatment standards in force [7]. This problem is more prominent in small, rural, insular or mountainous communities, where constructing and running a conventional Wastewater Treatment Plant (WWTP) is challenging and many times the latter fails to produce effluents of good quality [8][9][10]. In Greece, due to the mountainous terrain, quite a few communities belong to the very small (≤2000 p.e.)…”

Design of the Interceptor-Collector and Wastewater Treatment System for Pollution Mitigation: A Case Study

“…Furthermore, the lack of low-cost and straightforward management technologies makes it impossible to use them in rural areas and communities with low population density. Due to this, research has been developed to optimise the effluent purification processes [6]- [8]. In a context like a case addressed in this study, an example was carried out in the Montañita community, Ecuador.…”