# Application of New Filling Material Based on Combined Heat and Power Waste for Sewage Treatment in Constructed Wetlands

^{1}

^{2}

^{3}

^{*}

## Abstract

**:**

_{5}), 80.2% for chemical oxygen demand (COD), 80.4% for suspended solids (SSs), 80.2 for ammonia nitrogen (N-NH

_{4}), 72.2% for total nitrogen (TN), and 55.3% for total phosphorus (TP), while the gravel-filled bed achieved 84.5%, 77.0%, 86.9%, 74.2%, 69.4%, and 57.8% for the whole research period, respectively. A higher effect of the removed unit load was achieved in the bed filled with Certyd (36.2 g BOD

_{5}m

^{−2}d

^{−1}, 50.0 g COD m

^{−2}d

^{−1}, 5.88 g SS m

^{−2}d

^{−1}, 7.1 g TN m

^{−2}d

^{−1}, 7.9 g N-NH

_{4}m

^{−2}d

^{−1}, 0.79 g TP m

^{−2}d

^{−1}) compared to the gravel-filled bed (34.7 g BOD

_{5}m

^{−2}d

^{−1}, 47.0 g COD, 6.35 g SS m

^{−2}d

^{−1}, 6.9 g TN m

^{−2}d

^{−1}, 7.3 g m

^{−2}d

^{−1}N-NH

_{4}, 0.83 g TP m

^{−2}d

^{−1}).

## 1. Introduction

^{−3}, and the specific surface area of the grains is 700–1500 m

^{2}∙m

^{−3}[23]. These parameters allow intensive development of the biofilm and a significant increase in the contact area with wastewater. The hydraulic conductivity of expanded clay is up to 15 cm∙s

^{−1}[24]. CWs filled with LECA have better hydraulic conditions and are less sensitive to clogging than gravel-filled beds. The expanded structure of the surface of LECA indirectly influences the high efficiency of nitrogen and phosphorus removal [25,26].

^{−3}and a specific surface area of about 600 m

^{2}∙m

^{−3}, which is similar to the characteristic value for LECA. Aci-soluble sulfate content is 0.25%, while total sulfur content is 0.32%. The shattering resistance is no less than 6 MPa and the thermal conductivity λ = 0.14–0.16 W/mK. The Certyd characteristics and properties comply with lightweight aggregate standards (e.g., [29,30]).

## 2. Materials and Methods

#### 2.1. Research Installation and Sample Analysis

^{−1}. The loads used are typical for domestic wastewater treatment systems [10]. The beds were planted with reeds (Phragmites australis). The research was carried out over two years, and 45 series were collected. Each series consisted of a raw sewage sample (sampling point I) and two samples of treated sewage (sampling points II and III). Vegetation (April until November) and non-vegetation seasons were distinguished. The quality and quantity of raw sewage is an important parameter in the design and assessment of the effectiveness of treatment systems. The daily wastewater flow from the household was 0.25 ${\mathrm{m}}^{3}\xb7{\mathrm{d}}^{-1}$. The content of organic matter (BOD

_{5}, COD, TOC), suspended solids (SSs), total nitrogen (TN), ammonia nitrogen (NH

_{4}-N), and total phosphorus (TP) were analyzed. The tests recommended by Merck were performed in the Department of Environmental Engineering and Natural Sciences laboratory at Bialystok University of Technology. Wastewater testing was conducted following the requirements of the American Public Health Association [32]. Spectrophotometer Spectroquant Pharo 100 (Merck Millipore, Burlington, MA, USA) was used. BOD

_{5}was determined using OXI-TOP

^{®}(Xylem Analytics, Washington, DC, USA). In addition, measurements were taken of pH, conductivity, and dissolved oxygen concentration, using the multi-parameter device WTW MutiLine P4 (Labexchange, Burladingen, Germany).

#### 2.2. Statistical Methodology and Data Refining

- for each of the variables, the number of bars was determined;
- for each of the variables, bar widths were determined in proportion to the range;
- the smallest width was selected and the global number of bars for the full range was recalculated;
- the target width of the bars (${d}_{glob}$) was selected using the ‘pretty’ algorithm, where the previously calculated global number of bars was provided as a hint.

## 3. Results and Discussion

^{−1}cm s

^{−1}for Certyd (fraction: 1–4 mm) and 6.31 × 10

^{−1}cm s

^{−1}for gravel (fraction: 5–6 mm). Both materials had a high permeability coefficient. It is well known that a high value of the permeability coefficient results in better aeration and prevents clogging of CWs. Table 1 presents the characteristics of the wastewater quality used in the study. To be able to evaluate the efficiency of the treatment process, wastewater parameters are divided into vegetation and non-vegetation periods.

_{5}in the wastewater supplying the beds varied from 370 to 490 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-3}$ (410 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-3}$ on average), while COD is from 700 to 843 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-3}$ (average: 738 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-3}$). Similar parameters after primary sedimentation (BOD

_{5}: 488.5 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-3}$, COD: 880.0 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-3})$ were obtained in [39], while analyzing the effectiveness of five hybrid systems treating domestic wastewater plants. In the case of nutrients, the composition of wastewater was also similar. Long-term studies (1997–2010), conducted as part of the monitoring of domestic wastewater treatment plants with pre-treatment and CWs with horizontal flow [1], showed the following parameters: BOD

_{5}from 62 to 301 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-3}$ (average: 163.2 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-3}$), COD from 101 to 580 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-3}$ (average: 329.8 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-3}$), TN from 37.1 to 137 $\mathrm{g}\xb7{\mathrm{m}}^{-3}$ (average: 71.5 $\mathrm{g}\xb7{\mathrm{m}}^{-3}$), TP from 5.2 to 42.8 $\mathrm{g}\xb7{\mathrm{m}}^{-3}$ (average: 24.8 $\mathrm{g}\xb7{\mathrm{m}}^{-3}$).

_{5}, and COD concentration. The capacity of the tank, the number of chambers, and the possible use of chemical precipitation can significantly alter the parameters of CWs’ bed influent.

_{5}: 41.0 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-2}\xb7{\mathrm{d}}^{-1}$ (37.0 to 49.0 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-2}\xb7{\mathrm{d}}^{-1}$), COD: 73.8 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-2}\xb7{\mathrm{d}}^{-1},$ SS: 7.31 $\mathrm{g}\xb7{\mathrm{m}}^{-2}\xb7{\mathrm{d}}^{-1}$ (Table 2). No significant differences were observed in the beds’ loading during the study period. Figure 6, Figure 7, Figure 8, Figure 9, Figure 10, Figure 11 and Figure 12 present the parameters of treated sewage.

_{5}was 88.0% with an average value at the outflow of 48.0 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-3}$ for the Certyd-filled bed and 84.5% and 63.0 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-3}$ for the gravel-filled bed (Figure 6). Similarly, for COD, the efficiencies were 80.2 and 77.0% with values at the outflow of 146 and 169 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-3}$ (Figure 7). A similar trend was observed for TOC (Figure 8). Based on studies of a number of wastewater treatment plants in various countries, [9] reports a 90% BOD

_{5}removal efficiency in SS VF CWs and 85–87.5% COD removal efficiency in a hybrid treatment plant in Wiedersberg, during the growing season [41]. Organic matter removal efficiencies measured using COD at treatment plants in France ranged from 90.0 to 91.3% according to [42]. Removal efficiencies for BOD

_{5}and COD at treatment plants located in Beijing were 87.0 and 82.0% [43].

_{5}, the load removed (average value) was, for the gravel-filled bed, 34.7 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-2}{\mathrm{d}}^{-1}$ and 36.2 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-2}{\mathrm{d}}^{-1}$ for the Certyd-filled bed. In the case of COD, it was, respectively, 56.9 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-2}{\mathrm{d}}^{-1}$ and 59.2 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-2}{\mathrm{d}}^{-1}$. The literature notes even better results. The unit load removed in CWs treating fruit and vegetable processing wastewater was 71.24 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-2}{\mathrm{d}}^{-1}$ for BOD

_{5}and as high as 221.44 ${\mathrm{gO}}_{2}\xb7{\mathrm{m}}^{-2}{\mathrm{d}}^{-1}$ for COD [44].

_{4}removal, it was found for the entire study period that the efficiency for the gravel-filled bed was 74.2 and 80.2% for Certyd. For TN, it was 69.4 and 75.2%, respectively (Figure 5). This is confirmed by the parameters of the treated wastewater shown in Figure 9 and Figure 10. A range of TN removal from 23.0 to 43.0% was reported in [40]. The concentration of N-NH

_{4}was significantly lower for sewage treated in a Certyd-filled bed. A better nitrification effect was observed in the Certyd-filled bed: the concentration of nitrate nitrogen in the outflow from the Certyd-filled bed was 15.7 $\mathrm{g}\xb7{\mathrm{m}}^{-3}$, and from the gravel-filled bed, it was 11.4 $\mathrm{g}\xb7{\mathrm{m}}^{-3}$. Proper oxygenation of CW beds is indicated as the main factor influencing the nitrification process occurring in VF-CWs [10]. According to [9], the efficiency of TN removal in processes in SS VF beds was up to 43.0%, while N-NH

_{4}was up to 73%. N-NH

_{4}removal efficiencies ranging from 94.8 to 98.5%, and those of TN from 52.9 to 78.4%, were reported in [46].

_{4}was achieved per unit area of CWs (Table 3). TN removal was 6.9 $\mathrm{g}\xb7{\mathrm{m}}^{-2}{\mathrm{d}}^{-1}$ for the gravel-filled bed, while it was 7.1 $\mathrm{g}\xb7{\mathrm{m}}^{-2}{\mathrm{d}}^{-1}$ for the Certyd-filled bed. In the case of N-NH

_{4}, it was 7.3 $\mathrm{g}\xb7{\mathrm{m}}^{-2}{\mathrm{d}}^{-1}$ for the gravel-filled bed, and 7.9 $\mathrm{g}\xb7{\mathrm{m}}^{-2}{\mathrm{d}}^{-1}$ for the Certyd-filled bed. The Certyd-filled bed had better oxygenation, and hence higher N-NH

_{4}removal efficiency and lower nitrate removal efficiency. The efficiency of TN removal in the CWs is dependent on the efficiency of the denitrification process, which requires anoxic conditions. Such conditions can occur in horizontal flow or a hybrid CW system [10,13].

_{5}:COD and BOD

_{5}:TN ratios. Table 6 shows dissolved oxygen concentration, pH, conductivity, and alkalinity.

_{5}:COD ratio in raw sewage was 0.555, while BOD

_{5}:TN was 3.57. In treated sewage, it was 0.361 and 1.31 for the gravel-filled bed and 0.320 and 1.07 for the Certyd-filled bed. The obtained results seem to confirm the possibility of effective biological wastewater treatment. A similar favorable value of indicators for domestic sewage treated with constructed wetlands was obtained in [40]. Those indicators are also important in assessing the possibility of intensifying the treatment with a hybrid system [49]. The effectiveness of nitrification taking place in both CWs’ beds is confirmed by the analysis of alkalinity in raw and treated wastewater, as well as the concentrations of dissolved oxygen (Table 6). The mean alkalinity decreased from 13.6 to 7.4 $\mathrm{mval}\xb7{\mathrm{dm}}^{-3}$ in the Certyd-filled bed and 6.1 $\mathrm{mval}\xb7{\mathrm{dm}}^{-3}$ in the gravel-filled bed.

## 4. Conclusions

_{5}) and 80.2% (COD) in the Certyd-filled bed, while in the gravel-filled bed, it was 84.5% and 77.0, respectively. The removal effect of SS and TP was lower (80.4% and 55.3%) compared to the gravel-filled bed (86.9% and 57.8%). The average removal efficiency of nitrogen compounds throughout the study period in the beds filled with Certyd and gravel was 80.2 and 74.2% (N-NH

_{4}), and 61.1% and 59.1% (TN). Differences in reported efficiencies, in both the vegetative and non-vegetative periods, were statistically significant, most of them with very low p-values. The nitrification process occurred more efficiently in the Certyd-filled bed. This was related to the higher concentration of dissolved oxygen in the treated wastewater in the Certyd-filled bed, which was 2.43 g m

^{−3}, and 1.91 g m

^{−3}in the gravel-filled bed.

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## Abbreviations

_{5}—Biological Oxygen Demand, COD—Chemical Oxygen Demand, TOC—Total Carbon, N-NH

_{4}—Ammonia Nitrogen, TN—Total Nitrogen, TP—Total Phosphorus, SSs—Suspended Solids, LECA—Light Expanded Clay Aggregate, LWA—Lightweight Aggregate.

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**Figure 1.**Structure of the Certyd—microscope picture (

**a**), real-scale picture (

**b**). Part (

**a**): optical microscope, observation method: reflection, objective lens DSXPLFL3.6X, 4× zoom, 96× total magnification. Part (

**b**): 1–4 mm fraction.

**Figure 4.**Treatment efficiency—BOD

_{5}, COD, and SS: (

**a**) whole study period, (

**b**) non-vegetative period, (

**c**) vegetation period.

**Figure 5.**Treatment efficiency—TN, N-NH

_{4}, and TP: (

**a**) whole study period, (

**b**) non-vegetative period, (

**c**) vegetation period.

**Figure 6.**Parameters of treated sewage (gravel and Certyd)—BOD

_{5}: (

**a**) whole study period, (

**b**) non-vegetative period, (

**c**) vegetation period.

**Figure 7.**Parameters of treated sewage (gravel and Certyd)—COD: (

**a**) whole study period, (

**b**) non-vegetative period, (

**c**) vegetation period.

**Figure 8.**Parameters of treated sewage (gravel and Certyd)—TOC: (

**a**) whole study period, (

**b**) non-vegetative period, (

**c**) vegetation period.

**Figure 9.**Parameters of treated sewage (gravel and Certyd)—N-NH

_{4}: (

**a**) whole study period, (

**b**) non-vegetative period, (

**c**) vegetation period.

**Figure 10.**Parameters of treated sewage (gravel and Certyd)—TN: (

**a**) whole study period, (

**b**) non-vegetative period, (

**c**) vegetation period.

**Figure 11.**Parameters of treated sewage (gravel and Certyd)—TP: (

**a**) whole study period, (

**b**) non-vegetative period, (

**c**) vegetation period.

**Figure 12.**Parameters of treated sewage (gravel and Certyd)—SS: (

**a**) whole study period, (

**b**) non-vegetative period, (

**c**) vegetation period.

Parameter | Whole Research Period | Vegetation Period | Non-Vegetation Period |
---|---|---|---|

$\begin{array}{c}BO{D}_{5}\\ \left[\mathrm{g}{\mathrm{O}}_{2}\cdot {\mathrm{m}}^{-3}\right]\end{array}$ | $\begin{array}{c}\frac{410\pm 25\left(400\pm 30\right)}{370,395,430,490}\\ p1=0.07,p2=0.04\end{array}$ | $\begin{array}{c}\frac{415\pm 21\left(420\pm 19\right)}{370,400,430,440}\\ p1=0.81,p2=0.03\end{array}$ | $\begin{array}{c}\frac{406\pm 28\left(400\pm 15\right)}{370,390,410,490}\\ p10.01\end{array}$ |

$\begin{array}{c}COD\\ \left[\mathrm{g}{\mathrm{O}}_{2}\cdot {\mathrm{m}}^{-3}\right]\end{array}$ | $\begin{array}{c}\frac{738\pm 31\left(730\pm 30\right)}{700,720,755,843}\\ p1=0.16,p20.01\end{array}$ | $\begin{array}{c}\frac{736\pm 19\left(730\pm 22\right)}{700,723,750,760}\\ p1=0.64,p2=0.08\end{array}$ | $\begin{array}{c}\frac{740\pm 38\left(730\pm 30\right)}{700,720,760,843}\\ p1=0.10;p20.01\end{array}$ |

$\begin{array}{c}SS\\ \left[\mathrm{g}\cdot {\mathrm{m}}^{-3}\right]\end{array}$ | $\begin{array}{c}\frac{73.1\pm 5.2\left(72.0\pm 4.4\right)}{65.0,70.0,75.0,90.0}\\ p1=0.03\end{array}$ | $\begin{array}{c}\frac{71.9\pm 3.9\left(71.5\pm 3.7\right)}{65.0,70.0,75.0,80.0}\\ p1=0.71,p2=0.76\end{array}$ | $\begin{array}{c}\frac{73.8\pm 5.9\left(73.0\pm 4.4\right)}{65.0,70.0,75.0,90.0}\\ p1=0.10,p2=0.03\end{array}$ |

$\begin{array}{c}TN\\ \left[\mathrm{g}\cdot {\mathrm{m}}^{-3}\right]\end{array}$ | $\begin{array}{c}\frac{116\pm 13\left(113\pm 12\right)}{97,106,123,141}\\ p10.01\end{array}$ | $\begin{array}{c}\frac{118\pm 13\left(118\pm 11\right)}{98,111,126,140}\\ p1=0.90,p2=0.50\end{array}$ | $\begin{array}{c}\frac{113.7\pm 12.7\left(109.7\pm 8.5\right)}{97.0,105.2,118.3,141.5}\\ p10.01\end{array}$ |

$\begin{array}{c}N-N{H}_{4}\\ \left[\mathrm{g}\cdot {\mathrm{m}}^{-3}\right]\end{array}$ | $\begin{array}{c}\frac{97\pm 11\left(94\pm 12\right)}{85,89,105,120}\\ p1=0.05\end{array}$ | $\begin{array}{c}\frac{103\pm 12\left(104\pm 18\right)}{85,90,110,120}\\ p1=0.06,p2=0.06\end{array}$ | $\begin{array}{c}\frac{93.7\pm 8.1\left(90.0\pm 5.8\right)}{85.0,88.3,96.5,116.5}\\ p10.01\end{array}$ |

$\begin{array}{c}TP\\ \left[\mathrm{g}\cdot {\mathrm{m}}^{-3}\right]\end{array}$ | $\begin{array}{c}\frac{14.3\pm 2.3\left(14.0\pm 2.7\right)}{10.3,12.8,16.1,20.5}\\ p1=0.31,p2=0.35\end{array}$ | $\begin{array}{c}\frac{14.3\pm 1.4\left(14.0\pm 1.4\right)}{12.1,13.2,15.6,16.4}\\ p1=0.25,p2=0.16\end{array}$ | $\begin{array}{c}\frac{14.2\pm 2.8\left(14.1\pm 4.2\right)}{10.3,12.0,16.9,20.5}\\ p1=0.64,p2=0.16\end{array}$ |

Period | Load, g·m^{−2}·d^{−1} | BOD_{5} | COD | SS |
---|---|---|---|---|

Whole period | ${L}_{in}$ | $\begin{array}{c}\frac{41.0\pm 2.5\left(40.0\pm 3.0\right)}{37.0,39.5,43.0,49.0}\\ p1=0.07,p2=0.04\end{array}$ | $\begin{array}{c}\frac{73.8\pm 3.1\left(73.0\pm 3.0\right)}{70.0,72.0,75.5,84.3}\\ p1=0.16,p20.01\end{array}$ | $\begin{array}{c}\frac{7.31\pm 0.52\left(7.20\pm 0.44\right)}{6.50,7.00,7.50,9.00}\\ p1=0.03\end{array}$ |

${L}_{rem,Gravel}$ | $\begin{array}{c}\frac{34.7\pm 4.2\left(35.2\pm 5.6\right)}{27.5,31.0,38.3,44.4}\\ p1=0.78,p2=0.13\end{array}$ | $\begin{array}{c}\frac{56.9\pm 5.2\left(56.6\pm 5.3\right)}{47.0,53.0,60.8,67.8}\\ p1=0.97,p2=0.71\end{array}$ | $\begin{array}{c}\frac{6.35\pm 0.51\left(6.40\pm 0.44\right)}{5.10,6.05,6.55,7.60}\\ p1=0.49,p2=0.48\end{array}$ | |

${L}_{rem,Certyd}$ | $\begin{array}{c}\frac{36.2\pm 4.0\left(36.2\pm 5.8\right)}{29.2,32.4,39.8,45.0}\\ p1=0.92,p2=0.08\end{array}$ | $\begin{array}{c}\frac{59.2\pm 5.0\left(59.5\pm 5.9\right)}{50.0,55.0,62.8,68.5}\\ p1=0.45,p2=0.28\end{array}$ | $\begin{array}{c}\frac{5.88\pm 0.49\left(5.80\pm 0.44\right)}{5.20,5.45,6.10,7.20}\\ p1=0.20,p2=0.13\end{array}$ | |

Veg. period | ${L}_{in}$ | $\begin{array}{c}\frac{41.5\pm 2.1\left(42.0\pm 1.9\right)}{37.0,40.0,43.0,44.0}\\ p1=0.81,p2=0.03\end{array}$ | $\begin{array}{c}\frac{73.6\pm 1.9\left(73.0\pm 2.2\right)}{70.0,72.3,75.0,76.0}\\ p1=0.64,p2=0.08\end{array}$ | $\begin{array}{c}\frac{7.19\pm 0.39\left(7.15\pm 0.37\right)}{6.50,7.00,7.50,8.00}\\ p1=0.71,p2=0.76\end{array}$ |

${L}_{rem,Gravel}$ | $\begin{array}{c}\frac{37.3\pm 2.6\left(38.3\pm 2.4\right)}{30.6,35.8,39.1,40.0}\\ p1=0.30,p2=0.02\end{array}$ | $\begin{array}{c}\frac{60.3\pm 3.1\left(60.8\pm 3.3\right)}{53.0,58.6,62.9,64.2}\\ p1=0.22,p2=0.21\end{array}$ | $\begin{array}{c}\frac{6.39\pm 0.35\left(6.40\pm 0.30\right)}{5.90,6.18,6.53,7.20}\\ p1=0.71,p2=0.56\end{array}$ | |

${L}_{rem,Certyd}$ | $\begin{array}{c}\frac{38.4\pm 2.8\left(39.5\pm 2.3\right)}{31.4,36.5,40.4,41.3}\\ p1=0.15,p2=0.02\end{array}$ | $\begin{array}{c}\frac{62.5\pm 3.4\left(62.8\pm 3.9\right)}{54.0,60.6,65.3,66.4}\\ p1=0.15,p2=0.12\end{array}$ | $\begin{array}{c}\frac{5.76\pm 0.40\left(5.75\pm 0.44\right)}{5.20,5.40,6.00,6.60}\\ p1=0.16,p2=0.41\end{array}$ | |

Non-veg. period | ${L}_{in}$ | $\begin{array}{c}\frac{40.6\pm 2.8\left(40.0\pm 1.5\right)}{37.0,39.0,41.0,49.0}\\ p10.01\end{array}$ | $\begin{array}{c}\frac{74.0\pm 3.8\left(73.0\pm 3.0\right)}{70.0,72.0,76.0,84.3}\\ p1=0.10,p20.01\end{array}$ | $\begin{array}{c}\frac{7.38\pm 0.59\left(7.30\pm 0.44\right)}{6.50,7.00,7.50,9.00}\\ p1=0.10,p2=0.03\end{array}$ |

${L}_{rem,Gravel}$ | $\begin{array}{c}\frac{32.9\pm 4.1\left(31.0\pm 2.8\right)}{27.5,29.8,35.4,44.4}\\ p1=0.24,p20.01\end{array}$ | $\begin{array}{c}\frac{54.4\pm 5.0\left(53.5\pm 4.4\right)}{47.0,52.2,56.5,67.8}\\ p1=0.21,p2=0.02\end{array}$ | $\begin{array}{c}\frac{6.31\pm 0.65\left(6.20\pm 0.44\right)}{5.10,6.00,6.65,7.60}\\ p1=1.00,p2=0.92\end{array}$ | |

${L}_{rem,Certyd}$ | $\begin{array}{c}\frac{34.5\pm 3.9\left(33.0\pm 3.7\right)}{29.2,31.5,36.3,45.0}\\ p1=0.07,p2=0.06\end{array}$ | $\begin{array}{c}\frac{56.8\pm 4.8\left(55.6\pm 4.6\right)}{50.0,53.5,59.5,68.5}\\ p1=0.37,p2=0.05\end{array}$ | $\begin{array}{c}\frac{6.01\pm 0.57\left(6.00\pm 0.59\right)}{5.30,5.60,6.35,7.20}\\ p1=0.59,p2=0.53\end{array}$ |

Period | Load, g·m^{−2}·d^{−1} | TN | N-NH_{4} | TP |
---|---|---|---|---|

Whole period | ${L}_{in}$ | $\begin{array}{c}\frac{11.6\pm 1.3\left(11.3\pm 1.2\right)}{9.7,10.6,12.3,14.1}\\ p10.01\end{array}$ | $\begin{array}{c}\frac{9.7\pm 1.1\left(9.4\pm 1.2\right)}{8.5,8.9,10.5,12.0}\\ p10.05\end{array}$ | $\begin{array}{c}\frac{1.43\pm 0.23\left(1.40\pm 0.27\right)}{1.03,1.28,1.61,2.05}\\ p1=0.31.p2=0.35\end{array}$ |

${L}_{rem,Gravel}$ | $\begin{array}{c}\frac{6.9\pm 1.4\left(6.9\pm 1.5\right)}{5.0,5.8,7.8,9.6}\\ p1=0.11,p2=0.02\end{array}$ | $\begin{array}{c}\frac{7.3\pm 1.6\left(6.9\pm 2.1\right)}{4.8,6.3,8.8,10.4}\\ p1=0.02\end{array}$ | $\begin{array}{c}\frac{0.83\pm 0.17\left(0.82\pm 0.15\right)}{0.44,0.75,0.95,1.25}\\ p1=0.51.p2=0.85\end{array}$ | |

${L}_{rem,Certyd}$ | $\begin{array}{c}\frac{7.1\pm 1.4\left(6.6\pm 1.4\right)}{5.3,5.8,8.3,10.5}\\ p1=0.17,p2=0.01\end{array}$ | $\begin{array}{c}\frac{7.9\pm 1.4\left(7.6\pm 1.7\right)}{6.0,6.7,9.0,10.6}\\ p1=0.26,p2=0.02\end{array}$ | $\begin{array}{c}\frac{0.79\pm 0.15\left(0.77\pm 0.16\right)}{0.54,0.69,0.89,1.19}\\ p1=0.53.p2=0.52\end{array}$ | |

Veg. period | ${L}_{in}$ | $\begin{array}{c}\frac{11.8\pm 1.3\left(11.8\pm 1.1\right)}{9.8,11.1,12.6,14.0}\\ p1=0.90,p2=0.50\end{array}$ | $\begin{array}{c}\frac{10.3\pm 1.2\left(10.4\pm 1.8\right)}{8.5,9.0,11.0,12.0}\\ p1=0.06,p2=0.06\end{array}$ | $\begin{array}{c}\frac{1.43\pm 0.14\left(1.40\pm 0.14\right)}{1.21,1.32,1.56,1.64}\\ p1=0.25,p2=0.16\end{array}$ |

${L}_{rem,Gravel}$ | $\begin{array}{c}\frac{7.7\pm 1.2\left(7.7\pm 1.2\right)}{5.9,6.9,8.4,9.6}\\ p1=0.61,p2=0.27\end{array}$ | $\begin{array}{c}\frac{8.6\pm 1.3\left(8.8\pm 1.5\right)}{6.4,7.1,9.5,10.4}\\ p1=0.02\end{array}$ | $\begin{array}{c}\frac{0.859\pm 0.098\left(0.840\pm 0.089\right)}{0.720,0.793,0.905,1.090}\\ p1=0.12,p2=0.36\end{array}$ | |

${L}_{rem,Certyd}$ | $\begin{array}{c}\frac{8.0\pm 1.3\left(8.0\pm 1.3\right)}{5.9,7.2,8.8,10.5}\\ p1=0.94,p2=0.93\end{array}$ | $\begin{array}{c}\frac{8.7\pm 1.3\left(9.0\pm 1.6\right)}{6.7,7.3,9.5,10.6}\\ p1=0.02\end{array}$ | $\begin{array}{c}\frac{0.817\pm 0.112\left(0.795\pm 0.082\right)}{0.670,0.743,0.865,1.070}\\ p1=0.03\end{array}$ | |

Non-veg. period | ${L}_{in}$ | $\begin{array}{c}\frac{11.37\pm 1.27\left(10.97\pm 0.85\right)}{9.70,10.52,11.83,14.15}\\ p10.01\end{array}$ | $\begin{array}{c}\frac{9.37\pm 0.81\left(9.00\pm 0.58\right)}{8.50,8.83,9.65,11.65}\\ p10.01\end{array}$ | $\begin{array}{c}\frac{1.42\pm 0.28\left(1.41\pm 0.42\right)}{1.03,1.20,1.69,2.05}\\ p1=0.64,p2=0.16\end{array}$ |

${L}_{rem,Gravel}$ | $\begin{array}{c}\frac{6.31\pm 1.20\left(5.94\pm 0.95\right)}{4.97,5.51,6.91,9.11}\\ p1=0.01\end{array}$ | $\begin{array}{c}\frac{6.4\pm 1.1\left(6.3\pm 1.2\right)}{4.8,5.4,7.0,9.0}\\ p1=0.26,p2=0.31\end{array}$ | $\begin{array}{c}\frac{0.80\pm 0.21\left(0.80\pm 0.28\right)}{0.44,0.62,0.99,1.25}\\ p1=1.00,p2=0.65\end{array}$ | |

${L}_{rem,Certyd}$ | $\begin{array}{c}\frac{6.46\pm 1.15\left(6.12\pm 0.76\right)}{5.27,5.67,7.08,9.16}\\ p10.01\end{array}$ | $\begin{array}{c}\frac{7.2\pm 1.1\left(7.1\pm 1.2\right)}{6.0,6.2,7.9,9.8}\\ p1=0.29,p2=0.09\end{array}$ | $\begin{array}{c}\frac{0.77\pm 0.18\left(0.76\pm 0.24\right)}{0.54,0.60,0.92,1.19}\\ p1=0.07,p2=0.16\end{array}$ |

Period | Normality Test | Paired Test | Δη | ||||
---|---|---|---|---|---|---|---|

W Statistics | p-Value | Version | Statistics | p-Value | |||

${\eta}_{BO{D}_{5}}$ | Non-veg | 0.96281 | 0.4731 | T | t = 10.362 | $2.4\times {10}^{-10}$ | 0.040 |

Veg | 0.91165 | 0.0920 | T | t = 17.178 | $3.5\times {10}^{-12}$ | 0.027 | |

${\eta}_{COD}$ | Non-veg | 0.96815 | 0.5986 | T | t = 7.468 | $1.0\times {10}^{-7}$ | 0.033 |

Veg | 0.95179 | 0.4538 | T | t = 14.304 | $6.6\times {10}^{-11}$ | 0.029 | |

${\eta}_{TOC}$ | Non-veg | 0.91898 | 0.0486 | Wilcoxon | V = 325 | $1.3\times {10}^{-5}$ | 0.076 |

Veg | 0.95450 | 0.5000 | T | t = 9.7821 | $2.1\times {10}^{-8}$ | 0.042 | |

${\eta}_{N-N{H}_{4}}$ | Non-veg | 0.96365 | 0.4918 | T | t = 14.618 | $1.9\times {10}^{-13}$ | 0.090 |

Veg | 0.84572 | 0.0073 | Wilcoxon | V = 171 | $7.6\times {10}^{-6}$ | 0.016 | |

${\eta}_{TN}$ | Non-veg | 0.95978 | 0.4102 | T | t = 2.1204 | 0.04451 | 0.014 |

Veg | 0.95945 | 0.5909 | T | t = 4.347 | $4.4\times {10}^{-4}$ | 0.028 | |

${\eta}_{TP}$ | Non-veg | 0.94714 | 0.2160 | T | t = −2.4828 | 0.02042 | −0.021 |

Veg | 0.86944 | 0.0174 | Wilcoxon | V = 11 | $4.2\times {10}^{-4}$ | −0.031 | |

${\eta}_{SS}$ | Non-veg | 0.94302 | 0.5566 | T | t = −3.845 | 0.003238 | −0.040 |

Veg | 0.85908 | 0.0476 | Wilcoxon | V = 0 | $4.9\times {10}^{-4}$ | −0.082 |

BOD_{5}:COD | BOD_{5}:TN | |
---|---|---|

In | $\begin{array}{c}\frac{0.555\pm 0.020\left(0.556\pm 0.021\right)}{0.514,0.541,0.568,0.597}\\ p1=0.72,p2=0.84\end{array}$ | $\begin{array}{c}\frac{3.57\pm 0.25\left(3.54\pm 0.21\right)}{2.96,3.44,3.69,4.10}\\ p1=0.89,p2=0.84\end{array}$ |

Out Gravel | $\begin{array}{c}\frac{0.361\pm 0.061\left(0.356\pm 0.080\right)}{0.240,0.313,0.416,0.517}\\ p1=0.60,p2=0.39\end{array}$ | $\begin{array}{c}\frac{1.31\pm 0.39\left(1.21\pm 0.42\right)}{0.77,0.96,1.63,2.04}\\ p1=0.22,p20.01\end{array}$ |

Out Certyd | $\begin{array}{c}\frac{0.320\pm 0.066\left(0.300\pm 0.069\right)}{0.229,0.266,0.382,0.449}\\ p1=0.04\end{array}$ | $\begin{array}{c}\frac{1.07\pm 0.39\left(0.95\pm 0.38\right)}{0.53,0.77,1.34,1.95}\\ p1=0.02\end{array}$ |

**Table 6.**Dissolved oxygen concentration, pH, conductivity, and alkalinity of the raw sewage and treated sewage.

DO mg·dm ^{−3} | pH | Conductivity $\mathsf{\mu}\mathbf{S}\xb7\mathbf{c}{\mathbf{m}}^{\mathbf{-}\mathbf{1}}$ | Alkalinity $\mathbf{mval}\xb7\mathbf{d}{\mathbf{m}}^{\mathbf{-}\mathbf{3}}$ | |
---|---|---|---|---|

In | $\begin{array}{c}\frac{0.47\pm 0.24\left(0.45\pm 0.25\right)}{0.19,0.28,0.61,1.20}\\ p1=0.19,p20.01\end{array}$ | $6.6,7.0,7.1,7.2,7.3$ | $\begin{array}{c}\frac{1490\pm 66\left(1480\pm 59\right)}{1320,1440,1518,1670}\\ p10.01\end{array}$ | $\begin{array}{c}\frac{13.6\pm 2.6\left(14.0\pm 3.0\right)}{7.9,12.0,16.0,16.9}\\ p1=0.19,p2=0.11\end{array}$ |

Out Gravel | $\begin{array}{c}\frac{1.91\pm 0.56\left(1.80\pm 0.48\right)}{0.96,1.55,2.19,2.90}\\ p1=0.05,p2=0.37\end{array}$ | $7.0,7.1,7.2,7.3,7.4$ | $\begin{array}{c}\frac{1331\pm 96\left(1327\pm 104\right)}{1196,1275,1390,1494}\\ p1=0.88,p2=0.81\end{array}$ | $\begin{array}{c}\frac{6.1\pm 1.6\left(6.6\pm 1.8\right)}{3.8,4.3,7.2,8.0}\\ p1=0.14,p2=0.04\end{array}$ |

Out Certyd | $\begin{array}{c}\frac{2.43\pm 0.60\left(2.20\pm 0.65\right)}{1.62,1.90,3.00,3.60}\\ p1=0.57,p2=0.23\end{array}$ | $7.1,7.2,7.3,7.3,7.4$ | $\begin{array}{c}\frac{1299\pm 51\left(1300\pm 44\right)}{1230,1260,1320,1423}\\ p1=0.12,p2=0.18\end{array}$ | $\begin{array}{c}\frac{7.38\pm 1.07\left(8.00\pm 0.74\right)}{5.00,6.85,8.03,9.00}\\ p1=0.05\end{array}$ |

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## Share and Cite

**MDPI and ACS Style**

Malinowski, P.; Dąbrowski, W.; Karolinczak, B.
Application of New Filling Material Based on Combined Heat and Power Waste for Sewage Treatment in Constructed Wetlands. *Materials* **2024**, *17*, 389.
https://doi.org/10.3390/ma17020389

**AMA Style**

Malinowski P, Dąbrowski W, Karolinczak B.
Application of New Filling Material Based on Combined Heat and Power Waste for Sewage Treatment in Constructed Wetlands. *Materials*. 2024; 17(2):389.
https://doi.org/10.3390/ma17020389

**Chicago/Turabian Style**

Malinowski, Paweł, Wojciech Dąbrowski, and Beata Karolinczak.
2024. "Application of New Filling Material Based on Combined Heat and Power Waste for Sewage Treatment in Constructed Wetlands" *Materials* 17, no. 2: 389.
https://doi.org/10.3390/ma17020389