Wastewater Treatment Plants

Data Context

The visualization uses TidyTuesday’s Wastewater Plants dataset (Sep 2022), whose data context and information can be accessed at this link

HydroWASTE_v10 <- readr::read_csv('https://raw.githubusercontent.com/rfordatascience/tidytuesday/master/data/2022/2022-09-20/HydroWASTE_v10.csv')

Research Question

Out of all U.S. wastewater treatment plants, which have a dilution factor lower than 10 (which is regarded as a threshold for environmental concern)?

Data Transformation

Code

USA_wwtp <- HydroWASTE_v10 %>%
  filter(CNTRY_ISO %in% "USA") %>%
  filter(!is.na(DF)) %>%
  mutate(threshold = if_else(DF < 10, "lower", "within")) %>%
  mutate(df_cut = case_when(DF < 2 ~ "Under 2%", 
                            DF >= 2 & DF <  4 ~ "2-4%",
                            DF >= 4 & DF <  6 ~ "4-6%",
                            DF >= 6 & DF <  8 ~ "6-8%",
                            DF >= 8 & DF < 10 ~ "8-10%"))

Data Visualization

Code

n1 <- HydroWASTE_v10 %>%
  filter(CNTRY_ISO %in% "USA") %>%
  nrow()

n2 <- USA_wwtp %>% 
  filter(threshold == "lower") %>%
  nrow()

n2*100/n1

[1] 2.955665

Code

showtext_auto()

usa <- st_as_sf(maps::map("state", fill=TRUE, plot = FALSE))

ggplot(usa) +
  geom_sf(color = "grey80", fill = "#2C3E4C", size = 0.125) +
  geom_point(data = USA_wwtp %>% filter(threshold == "within"), aes(LON_OUT, LAT_OUT), alpha = 0.1, size = 0.08, color = "#949398FF") +
  geom_point(data = USA_wwtp %>% filter(threshold == "lower"), aes(LON_OUT, LAT_OUT, color = df_cut), alpha = 0.8, size = 1) +
  guides(colour = guide_legend(override.aes = list(size = 6, alpha = 0.8))) +
  labs(title = "Wastewater Dilution Below Regulatory Threshold (<10% Dilution) in the United States", subtitle = "2.9% (438 out of 14,819) of US Wastewater Treatment Plants have a Dilution Factor Lower than the Threshold for Environmental Concern", color = str_wrap("Regulatory Threshold", 8), caption = "Data: Macedo et al, 2022 (Tidy Tuesday 2022, week 38) | Graphic Design Inspired by Github Account @NearAndDistant") +
  rcartocolor::scale_color_carto_d(palette = "PinkYl") + 
  coord_sf(lims_method = "geometry_bbox") +
  theme_void() +
  theme(legend.position   = "right",
        text = element_text(color = "white", family = "Inter"),
        legend.title      = element_text(face = "bold"),
        plot.title        = element_text(color = "white", face = "bold", size = 15),
        plot.caption      = element_text(hjust = 0), 
        panel.background  = element_rect(fill = "#21242b", color = "#21242b"),
        plot.background   = element_rect(fill = "#21242b", color = "#21242b"),
        plot.margin       = margin(20,20,20,20, unit = "pt"))

South Central region (especially around Northwest Texas region) and California have a higher concentration of wastewater treatment plants with a dilution factor below regulatory threshold.

Credit

The visualization uses the template from Github user @NearAndDistant at this link