Yaya-Beas, R.-E., et al. Helminth Egg Removal Capacity of UASB Reactors under Subtropical Conditions. Water 2015, 7, 2402–2421

The authors wish to make the following corrections to their paper [1]:

1.

In the third paragraph of the Introduction section, on lines 6, 8 and 9: “egg·g⁻¹” is replaced by “eggs·L⁻¹”.

The corrected paragraph, therefore, reads as follows:

Within the group of technologies applied to physical helminth egg removal (not inactivation) from wastewater, land-based post-treatment technologies such as sand filtration, wetlands and polishing ponds are reported to achieve helminth egg removal of 90%–99%, 100% and 100%, respectively [1,25,26]. In addition, Jimenez [19] reported that grit removal followed by a coagulation flocculation process in what is known as advanced primary treatment (APT), combined with an upflow sand filtration, reduced the amount of helminth eggs from 1.2 to 0.2 eggs·L⁻¹. Additionally, a study using APT, followed by a sand filter combined with a synthetic medium, reduced the amount of helminth eggs in average from 26 to 1.2 eggs·L⁻¹. Furthermore, APT followed by a multimedia filter and inclined parallel plates reduced the concentration from 27.0 to 1.2 eggs·L⁻¹ [19].

2.

In Table 1, row 11: “egg·g⁻¹” is replaced by “eggs·L⁻¹”.

The corrected Table 1 is therefore as follows:

Table 1. Influent wastewater characteristics from two urban villages called El Angel and El Milagro located in Lima (Peru), used for this research.

Parameter	Units	Average	n
Chemical Oxygen Demand	mg·L−1	723.2 ± 320.3	90
Suspended Solids	mg·L−1	126.5 ± 28.5	36
Oils and Grease	mg·L−1	30.8 ± 14.1	36
Total Phosphorous—P	mg·L−1	6.6 ± 2	35
Total Kjeldahl nitrogen—TKN	mg·L−1	16.2 ± 6.5	36
Dissolved Oxygen	mg·L−1	6.8 ± 0.4	36
Temperature	°C	22.8 ± 4.1	233
pH	--	7.1 ± 0.3	233
Fecal Coliforms	MPN/100 mL	9.67 × 108 ± 1.89 × 108	36
Helminth eggs	eggs·L−1	2.4 ± 1.4	90

Note: Where n is a number of grab samples analyzed.

Table 1. Influent wastewater characteristics from two urban villages called El Angel and El Milagro located in Lima (Peru), used for this research.

Parameter	Units	Average	n
Chemical Oxygen Demand	mg·L−1	723.2 ± 320.3	90
Suspended Solids	mg·L−1	126.5 ± 28.5	36
Oils and Grease	mg·L−1	30.8 ± 14.1	36
Total Phosphorous—P	mg·L−1	6.6 ± 2	35
Total Kjeldahl nitrogen—TKN	mg·L−1	16.2 ± 6.5	36
Dissolved Oxygen	mg·L−1	6.8 ± 0.4	36
Temperature	°C	22.8 ± 4.1	233
pH	--	7.1 ± 0.3	233
Fecal Coliforms	MPN/100 mL	9.67 × 108 ± 1.89 × 108	36
Helminth eggs	eggs·L−1	2.4 ± 1.4	90

Note: Where n is a number of grab samples analyzed.

3.

The second paragraph of the Materials and Methods section, line 6: “egg·g⁻¹” is replaced by “eggs·L⁻¹”.

The corrected paragraph currently reads as follows:

The wastewater was pumped daily into a 200 L tank. The tank was filled with fresh wastewater every morning for all cases except when the upflow velocity of 0.68 m·h⁻¹ was tested. For the latter situation, it was filled again in the afternoon when the remaining volume of the wastewater was 20 L. After filling the tank, the wastewater was mixed using a mechanical stirrer (18 RPM) with a stock solution containing Ascaris suum. The helminth egg concentration in the tank varied between 20–50 eggs·L⁻¹. The tank was kept at ambient temperatures and its content was used to continuously feed the UASB reactors. The pH and temperature of the wastewater was measured daily at 9:00, 12:00 and 16:00. The setup of the experiments is shown in Figure 1.

4.

The last paragraph of Materials and Methods section, line 3: “egg·g⁻¹” is replaced by “eggs·L⁻¹”.

The corrected paragraph reads as follows:

Experiment 1 was performed after 85 days of the start of the UASB reactor. Before starting Experiment 2, reactors were operated for approximately 30 days and continuously fed with domestic wastewater containing an average helminth egg concentration of 2.4 eggs·L⁻¹ and an HRT of 4 h. The two reactors were fed with exactly the same influent using two peristaltic pumps (2 Masterflex, Oldham, UK). Some samples from the effluent in Experiment 2 were taken for each upflow velocity in order to do microscopic observations. Experiment 3 started immediately after finishing Experiment 2. Experiment 4 (control experiment) was performed without sludge in the acrylic UASB reactor 7 days after all experiments were finished. All experiments were performed at ambient temperatures. Sludge was removed in each UASB reactor in order to maintain the established sludge bed height variation according to Table 2.

The supplementary file contains the corrected paper. We would like to apologize for any inconvenience caused to the readers.