Slow Sand Filtration (Biological Filtration)

mkdir -p /home/daytona/workspace/water-treatment-notes && ls /home/daytona/works…

~/water-treatment-notes/generate_pdf.py

from reportlab.lib.pagesizes import A4
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.units import cm, mm
from reportlab.lib import colors
from reportlab.platypus import (
    SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle,
    HRFlowable, PageBreak, KeepTogether
)
from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_JUSTIFY

OUTPUT = "/home/daytona/workspace/water-treatment-notes/Water_Treatment_Methods_PSM.pdf"

doc = SimpleDocTemplate(
    OUTPUT,
    pagesize=A4,
    leftMargin=2*cm, rightMargin=2*cm,
    topMargin=2.2*cm, bottomMargin=2.2*cm,
    title="Water Treatment Methods – PSM Exam Notes",
    author="Orris Medical Library"
)

styles = getSampleStyleSheet()

# Custom styles
TEAL = colors.HexColor("#006666")
DARK_TEAL = colors.HexColor("#004444")
ACCENT = colors.HexColor("#008080")
LIGHT_TEAL = colors.HexColor("#e0f5f5")
LIGHT_YELLOW = colors.HexColor("#fffbe6")
LIGHT_RED = colors.HexColor("#fff0f0")
BOX_BG = colors.HexColor("#f0fafa")

title_style = ParagraphStyle("DocTitle", parent=styles["Title"],
    fontSize=22, textColor=colors.white, alignment=TA_CENTER,
    spaceAfter=4, fontName="Helvetica-Bold")

subtitle_style = ParagraphStyle("DocSubtitle", parent=styles["Normal"],
    fontSize=11, textColor=colors.HexColor("#cceeee"), alignment=TA_CENTER,
    spaceAfter=2, fontName="Helvetica")

h1 = ParagraphStyle("H1", parent=styles["Heading1"],
    fontSize=14, textColor=colors.white, fontName="Helvetica-Bold",
    spaceBefore=14, spaceAfter=6, leading=18)

h2 = ParagraphStyle("H2", parent=styles["Heading2"],
    fontSize=12, textColor=DARK_TEAL, fontName="Helvetica-Bold",
    spaceBefore=10, spaceAfter=4, leading=16)

h3 = ParagraphStyle("H3", parent=styles["Heading3"],
    fontSize=10.5, textColor=ACCENT, fontName="Helvetica-Bold",
    spaceBefore=7, spaceAfter=3, leading=14)

body = ParagraphStyle("Body", parent=styles["Normal"],
    fontSize=9.5, leading=14, spaceAfter=5, fontName="Helvetica",
    alignment=TA_JUSTIFY)

bullet = ParagraphStyle("Bullet", parent=styles["Normal"],
    fontSize=9.5, leading=13, spaceAfter=3, fontName="Helvetica",
    leftIndent=14, bulletIndent=2)

bullet2 = ParagraphStyle("Bullet2", parent=styles["Normal"],
    fontSize=9, leading=13, spaceAfter=2, fontName="Helvetica",
    leftIndent=28, bulletIndent=16)

key_box = ParagraphStyle("KeyBox", parent=styles["Normal"],
    fontSize=9.5, leading=14, fontName="Helvetica",
    leftIndent=8, rightIndent=8, spaceAfter=3)

mnemonic = ParagraphStyle("Mnemonic", parent=styles["Normal"],
    fontSize=10, leading=15, fontName="Helvetica-Bold",
    textColor=colors.HexColor("#663300"),
    leftIndent=8, spaceAfter=3)

source = ParagraphStyle("Source", parent=styles["Normal"],
    fontSize=8, textColor=colors.grey, alignment=TA_CENTER,
    spaceAfter=2, fontName="Helvetica-Oblique")

def section_header(text, color=TEAL):
    tbl = Table([[Paragraph(text, h1)]], colWidths=[17*cm])
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), color),
        ("TOPPADDING", (0,0), (-1,-1), 6),
        ("BOTTOMPADDING", (0,0), (-1,-1), 6),
        ("LEFTPADDING", (0,0), (-1,-1), 10),
        ("ROUNDEDCORNERS", [4,4,4,4]),
    ]))
    return tbl

def info_box(paragraphs, bg=LIGHT_TEAL, border=ACCENT):
    content = [[p] for p in paragraphs]
    tbl = Table([[Paragraph("", body)] + [] for _ in [1]], colWidths=[17*cm])
    # Simpler approach
    rows = [[p] for p in paragraphs]
    inner = Table(rows, colWidths=[16.4*cm])
    inner.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), bg),
        ("LEFTPADDING", (0,0), (-1,-1), 10),
        ("RIGHTPADDING", (0,0), (-1,-1), 10),
        ("TOPPADDING", (0,0), (0,0), 8),
        ("BOTTOMPADDING", (0,-1), (-1,-1), 8),
        ("TOPPADDING", (0,1), (-1,-1), 2),
        ("BOTTOMPADDING", (0,0), (-1,-2), 2),
        ("LINEAFTER", (0,0), (0,-1), 4, border),
        ("BOX", (0,0), (-1,-1), 0.5, border),
    ]))
    return inner

def make_table(headers, rows, col_widths=None):
    if col_widths is None:
        col_widths = [17*cm / len(headers)] * len(headers)
    header_style = ParagraphStyle("TH", parent=styles["Normal"],
        fontSize=9, fontName="Helvetica-Bold", textColor=colors.white,
        alignment=TA_CENTER, leading=12)
    cell_style = ParagraphStyle("TD", parent=styles["Normal"],
        fontSize=8.5, fontName="Helvetica", leading=12, alignment=TA_LEFT)
    center_cell = ParagraphStyle("TDC", parent=styles["Normal"],
        fontSize=8.5, fontName="Helvetica", leading=12, alignment=TA_CENTER)

    data = [[Paragraph(h, header_style) for h in headers]]
    for row in rows:
        data.append([Paragraph(str(c), cell_style) for c in row])

    tbl = Table(data, colWidths=col_widths, repeatRows=1)
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,0), TEAL),
        ("GRID", (0,0), (-1,-1), 0.5, colors.HexColor("#b0d8d8")),
        ("ROWBACKGROUNDS", (0,1), (-1,-1), [colors.white, LIGHT_TEAL]),
        ("TOPPADDING", (0,0), (-1,-1), 5),
        ("BOTTOMPADDING", (0,0), (-1,-1), 5),
        ("LEFTPADDING", (0,0), (-1,-1), 6),
        ("RIGHTPADDING", (0,0), (-1,-1), 6),
        ("VALIGN", (0,0), (-1,-1), "TOP"),
    ]))
    return tbl

def bp(text):
    return Paragraph(f"• {text}", bullet)

def bp2(text):
    return Paragraph(f"◦ {text}", bullet2)

def bold(text):
    return f"<b>{text}</b>"

story = []

# ─── COVER PAGE ───────────────────────────────────────────────────────────────
cover = Table([[Paragraph("WATER TREATMENT METHODS", title_style),
                Paragraph("Preventive &amp; Social Medicine | Exam Preparation Notes", subtitle_style),
                Paragraph("Source: Park's Textbook of Preventive and Social Medicine", subtitle_style)]],
              colWidths=[17*cm])
cover.setStyle(TableStyle([
    ("BACKGROUND", (0,0), (-1,-1), DARK_TEAL),
    ("TOPPADDING", (0,0), (-1,-1), 18),
    ("BOTTOMPADDING", (0,0), (-1,-1), 18),
    ("LEFTPADDING", (0,0), (-1,-1), 14),
    ("RIGHTPADDING", (0,0), (-1,-1), 14),
    ("ROUNDEDCORNERS", [6,6,6,6]),
]))
story.append(cover)
story.append(Spacer(1, 0.5*cm))
story.append(Paragraph("Full Detailed Notes | All Methods, Comparisons &amp; Tables", source))
story.append(HRFlowable(width="100%", thickness=1, color=ACCENT))
story.append(Spacer(1, 0.3*cm))

# TABLE OF CONTENTS
story.append(section_header("TABLE OF CONTENTS"))
story.append(Spacer(1, 0.3*cm))
toc_items = [
    ("1", "Overview of Water Purification", ""),
    ("2", "Stage I – Storage", ""),
    ("3", "Stage II – Filtration", ""),
    ("  3a", "Slow Sand (Biological) Filters", ""),
    ("  3b", "Rapid Sand (Mechanical) Filters", ""),
    ("  3c", "Comparison Table: Slow vs Rapid Sand Filters", ""),
    ("4", "Stage III – Disinfection (Chlorination)", ""),
    ("  4a", "Action of Chlorine", ""),
    ("  4b", "Principles of Chlorination", ""),
    ("  4c", "Methods of Chlorination", ""),
    ("  4d", "Breakpoint Chlorination", ""),
    ("  4e", "Superchlorination & Dechlorination", ""),
    ("5", "Household / Individual Water Purification", ""),
    ("  5a", "Boiling", ""),
    ("  5b", "Chemical Disinfection (Bleaching Powder, HTH, Iodine etc.)", ""),
    ("  5c", "Filtration Candles", ""),
    ("6", "Key Numbers & Exam Facts", ""),
]
toc_data = [[Paragraph(f"<b>{n}</b>", body), Paragraph(t, body)] for n,t,_ in toc_items]
toc_tbl = Table(toc_data, colWidths=[1.5*cm, 15.5*cm])
toc_tbl.setStyle(TableStyle([
    ("TOPPADDING", (0,0), (-1,-1), 3),
    ("BOTTOMPADDING", (0,0), (-1,-1), 3),
    ("LEFTPADDING", (0,0), (0,-1), 8),
    ("ROWBACKGROUNDS", (0,0), (-1,-1), [colors.white, LIGHT_TEAL]),
    ("GRID", (0,0), (-1,-1), 0.3, colors.HexColor("#ccdddd")),
]))
story.append(toc_tbl)
story.append(PageBreak())

# ─── SECTION 1: OVERVIEW ──────────────────────────────────────────────────────
story.append(section_header("1. OVERVIEW OF WATER PURIFICATION"))
story.append(Spacer(1, 0.3*cm))
story.append(Paragraph("The method of treatment depends on the nature of raw water and desired standards of quality.", body))
story.append(bp(bold("Ground water") + " (wells, springs) – may only need disinfection"))
story.append(bp(bold("Surface water") + " (river water) – tends to be turbid and polluted; requires extensive treatment"))
story.append(Spacer(1, 0.3*cm))
story.append(Paragraph(bold("Components of a typical water purification system:"), h2))
story.append(info_box([
    Paragraph("I. &nbsp;&nbsp;<b>Storage</b> &nbsp;&nbsp; → &nbsp;&nbsp; II. <b>Filtration</b> &nbsp;&nbsp; → &nbsp;&nbsp; III. <b>Disinfection</b>", ParagraphStyle("flow", parent=styles["Normal"], fontSize=12, fontName="Helvetica-Bold", textColor=DARK_TEAL, alignment=TA_CENTER, leading=18)),
    Paragraph("Filtration alone removes <b>98–99%</b> of bacteria. Disinfection (chlorination) is a <i>supplement</i>, not a substitute, for filtration.", key_box),
]))
story.append(Spacer(1, 0.3*cm))

# ─── SECTION 2: STORAGE ───────────────────────────────────────────────────────
story.append(section_header("2. STAGE I – STORAGE"))
story.append(Spacer(1, 0.3*cm))
story.append(Paragraph("Water is drawn from the source and impounded in natural or artificial reservoirs. Storage excludes further pollution and allows natural purification:", body))

storage_rows = [
    ["Physical", "~90% of suspended impurities settle by gravity within 24 hours. Water becomes clearer, allowing light penetration and reducing filter load."],
    ["Chemical", "Aerobic bacteria oxidize organic matter using dissolved oxygen. Free ammonia content is reduced; nitrate content rises."],
    ["Biological", "Tremendous drop in bacterial count. Pathogenic organisms gradually die. River water stored for 5–7 days loses up to 90% of bacterial count."],
]
story.append(make_table(["Mechanism", "Effect"], storage_rows, [3.5*cm, 13.5*cm]))
story.append(Spacer(1, 0.3*cm))
story.append(info_box([
    Paragraph("&#x2605; <b>Optimum storage period for river water:</b> 10–14 days", key_box),
    Paragraph("&#x26A0; Prolonged storage can cause <b>algal growth</b> (imparts bad smell and colour)", key_box),
]))
story.append(PageBreak())

# ─── SECTION 3: FILTRATION ────────────────────────────────────────────────────
story.append(section_header("3. STAGE II – FILTRATION"))
story.append(Spacer(1, 0.3*cm))
story.append(Paragraph("Filtration is the second stage of water purification. It removes <b>98–99% of bacteria</b> along with other impurities. Two types of filters are used:", body))
story.append(bp(bold("Slow Sand Filter") + " – also called Biological Filter"))
story.append(bp(bold("Rapid Sand Filter") + " – also called Mechanical Filter"))

# 3a: Slow Sand Filter
story.append(Spacer(1, 0.4*cm))
story.append(Paragraph("3a. SLOW SAND (BIOLOGICAL) FILTERS", h2))
story.append(HRFlowable(width="100%", thickness=1, color=ACCENT))
story.append(Spacer(1, 0.2*cm))
story.append(info_box([
    Paragraph("&#x1F4CD; First used in <b>1804 in Scotland</b>, then London. Still considered the <b>standard method</b> of water purification worldwide.", key_box),
]))
story.append(Spacer(1, 0.2*cm))

story.append(Paragraph("Elements of a Slow Sand Filter:", h3))
story.append(Paragraph("A slow sand filter has <b>four essential elements</b>:", body))

elements = [
    ["1", "Supernatant (raw) water", "Depth 1–1.5 m. Provides constant head of pressure for downward flow. Allows partial purification by sedimentation, oxidation, and particle agglomeration (3–12 hrs). Level kept constant at all times."],
    ["2", "Sand bed", "Thickness ~1.2 m. Sand grain diameter: 0.2–0.3 mm (rounded). Must be clean, free from clay and organic matter. Supported by graded gravel (30–40 cm deep). 1 m³ of sand = 15,000 m² surface area."],
    ["3", "Under-drainage system", "Porous or perforated pipes at the bottom. Dual purpose: outlet for filtered water + supports the filter medium above."],
    ["4", "Filter control valves", "Venturi meter + valves in outlet pipe. Maintain constant rate of filtration."],
]
story.append(make_table(["No.", "Element", "Details"], elements, [0.8*cm, 3.8*cm, 12.4*cm]))
story.append(Spacer(1, 0.3*cm))

story.append(Paragraph("Filter Box Dimensions:", h3))
dim_rows = [
    ["Supernatant water", "1.0 – 1.5 m"],
    ["Sand bed", "1.2 m"],
    ["Gravel support", "0.30 m"],
    ["Filter bottom", "0.16 m"],
    ["Total depth", "2.5 – 4.0 m"],
]
story.append(make_table(["Layer", "Depth"], dim_rows, [8.5*cm, 8.5*cm]))
story.append(Spacer(1, 0.3*cm))

story.append(Paragraph("Purification Processes in the Sand Bed:", h3))
story.append(Paragraph("Water percolates very slowly through the sand bed (takes <b>2 hours or more</b>). Multiple processes act simultaneously:", body))
processes = ["Mechanical straining", "Sedimentation", "Adsorption", "Oxidation", "Bacterial action (most important)"]
for p in processes:
    story.append(bp(p))

story.append(Paragraph(f"<b>Rate of filtration:</b> 0.1–0.4 m³/hour/m² of sand bed surface", body))
story.append(Spacer(1, 0.3*cm))

story.append(Paragraph("The Vital Layer (Schmutzdecke)", h3))
story.append(info_box([
    Paragraph("The <b>Schmutzdecke</b> (also called vital layer, zoogleal layer, or biological layer) is the <b>HEART of the slow sand filter</b>.", key_box),
    Paragraph("&#x2022; Formed after a new filter starts running – initially acts only as a mechanical strainer", key_box),
    Paragraph("&#x2022; Consists of: threadlike algae, plankton, diatoms, and bacteria", key_box),
    Paragraph("&#x2022; Slimy, gelatinous layer extending <b>2–3 cm</b> into the top of the sand bed", key_box),
    Paragraph("&#x2022; Formation process = <b>'Ripening'</b> of the filter (takes several days to form fully)", key_box),
    Paragraph("&#x2022; Until fully formed, the first few days' filtrate is run to <b>WASTE</b>", key_box),
], bg=LIGHT_YELLOW, border=colors.HexColor("#cc9900"]))
story.append(Spacer(1, 0.2*cm))
story.append(Paragraph("<b>Functions of the Vital Layer:</b>", h3))
story.append(bp("Removes organic matter"))
story.append(bp("Holds back bacteria"))
story.append(bp("Oxidizes ammoniacal nitrogen into nitrates"))
story.append(bp("Helps yield bacteria-free water"))
story.append(Spacer(1, 0.3*cm))

story.append(Paragraph("Cleaning of Slow Sand Filters:", h3))
clean_rows = [
    ["Trigger", "Rate of filtration falls to a very low level (filter clogged)"],
    ["Interval", "Every 4–6 weeks in summer; every 2–3 months in winter"],
    ["Method", "1. Drain supernatant water\n2. Scrape off top 1.5–2 cm of sand\n3. Wash and store scraped sand\n4. Return filter to service\n5. When sand bed reaches 0.6–0.8 m depth, replace stored sand"],
    ["Note", "After cleaning, filter must re-ripen (vital layer reform) before use"],
]
story.append(make_table(["Aspect", "Detail"], clean_rows, [4*cm, 13*cm]))
story.append(PageBreak())

# 3b: Rapid Sand Filter
story.append(Paragraph("3b. RAPID SAND (MECHANICAL) FILTERS", h2))
story.append(HRFlowable(width="100%", thickness=1, color=ACCENT))
story.append(Spacer(1, 0.2*cm))
story.append(info_box([
    Paragraph("&#x1F4CD; First installed in the <b>USA in 1885</b>. Now very popular in highly industrialized countries.", key_box),
    Paragraph("Two types: <b>Gravity type</b> (Paterson's filter) and <b>Pressure type</b> (Candy's filter).", key_box),
]))
story.append(Spacer(1, 0.2*cm))

story.append(Paragraph("Steps in Purification by Rapid Sand Filter:", h3))
steps = [
    ["1", "Coagulation", "Raw water treated with chemical coagulant (usually alum, 5–40 mg/litre depending on turbidity, colour, temperature, and pH)"],
    ["2", "Rapid Mixing", "Treated water undergoes violent agitation in a mixing chamber for a few minutes – ensures thorough dissemination of alum"],
    ["3", "Flocculation", "Slow, gentle stirring in a flocculation chamber for ~30 minutes using mechanical paddles (2–4 rpm) → forms thick, white flocculant precipitate of aluminium hydroxide"],
    ["4", "Sedimentation", "Coagulated water detained in sedimentation tanks for 2–6 hours. Floc + impurities + bacteria settle. At least 95% of floc must be removed before filtration."],
    ["5", "Filtration", "Partly clarified water passed through rapid sand filter beds"],
    ["6", "Backwashing", "Cleaning done by reversing flow of water through the sand bed. Takes ~15 minutes. Compressed air may be used. Stops when clear sand and clear wash water are visible."],
]
story.append(make_table(["Step", "Process", "Details"], steps, [0.8*cm, 3.5*cm, 12.7*cm]))
story.append(Spacer(1, 0.3*cm))

story.append(Paragraph("Rapid Filter Bed Specifications:", h3))
spec_rows = [
    ["Filter bed surface area", "~80–90 m² per unit"],
    ["Sand effective size", "0.4–0.7 mm"],
    ["Sand bed depth", "~1 metre"],
    ["Gravel layer depth", "30–40 cm"],
    ["Water depth above sand", "1.0–1.5 m"],
    ["Rate of filtration", "5–15 m³/m²/hour (40–50x faster than slow sand)"],
]
story.append(make_table(["Specification", "Value"], spec_rows, [8*cm, 9*cm]))
story.append(Spacer(1, 0.3*cm))

story.append(Paragraph("Advantages of Rapid Sand Filter over Slow Sand Filter:", h3))
adv = [
    "Can deal with raw water directly – no preliminary storage needed",
    "Filter beds occupy less space",
    "Filtration rate is 40–50 times that of a slow sand filter",
    "Washing is easy (backwashing, 15 min) – no scraping needed",
    "More flexibility in operation",
]
for a in adv:
    story.append(bp(a))
story.append(PageBreak())

# 3c: Comparison Table
story.append(Paragraph("3c. COMPARISON: SLOW SAND vs. RAPID SAND FILTERS", h2))
story.append(HRFlowable(width="100%", thickness=1, color=ACCENT))
story.append(Spacer(1, 0.3*cm))
comp_rows = [
    ["Space required", "Large area needed", "Very little space"],
    ["Rate of filtration", "2–3 m.g.a.d. (0.1–0.4 m³/hr/m²)", "200 m.g.a.d. (5–15 m³/hr/m²)"],
    ["Effective sand size", "0.2–0.3 mm (finer)", "0.4–0.7 mm (coarser)"],
    ["Preliminary treatment", "Plain sedimentation (storage)", "Chemical coagulation + sedimentation"],
    ["Coagulant required", "No", "Yes (Alum, 5–40 mg/L)"],
    ["Cleaning method", "Scraping the sand bed surface (1.5–2 cm)", "Backwashing (15 minutes)"],
    ["Cleaning interval", "Every 4–6 weeks (summer)", "Every few days to daily"],
    ["Skilled operator", "Not required", "Highly skilled required"],
    ["Loss of head allowed", "4 feet (1.5 m)", "6–8 feet (2–2.5 m)"],
    ["Removal of turbidity", "Good", "Good"],
    ["Removal of colour", "Fair", "Good"],
    ["Removal of bacteria", "99.9–99.99%", "98–99%"],
    ["Vital layer (Schmutzdecke)", "Present – ESSENTIAL", "Absent"],
    ["Running cost", "Low", "Higher"],
    ["First used", "1804, Scotland", "1885, USA"],
]
story.append(make_table(["Feature", "Slow Sand Filter", "Rapid Sand Filter"], comp_rows, [5*cm, 6*cm, 6*cm]))
story.append(Spacer(1, 0.3*cm))
story.append(info_box([
    Paragraph("&#x2605; <b>Exam note:</b> Slow sand filters remove MORE bacteria (99.9–99.99%) than rapid sand filters (98–99%) despite being slower – because of the vital layer's biological action.", key_box),
], bg=LIGHT_YELLOW, border=colors.HexColor("#cc9900")))
story.append(PageBreak())

# ─── SECTION 4: DISINFECTION / CHLORINATION ───────────────────────────────────
story.append(section_header("4. STAGE III – DISINFECTION (CHLORINATION)"))
story.append(Spacer(1, 0.3*cm))
story.append(Paragraph("<b>Criteria for an ideal water disinfectant:</b>", h3))
criteria = [
    "Capable of destroying pathogens within the contact time available",
    "Not unduly influenced by temperature, pH, or mineral content of water",
    "Should not leave toxic reaction products or impair palatability",
    "Readily and dependably available at reasonable cost",
    "Leaves residual concentration to deal with subsequent recontamination",
    "Detectable by simple, rapid analytical techniques in small concentrations",
]
for c in criteria:
    story.append(bp(c))
story.append(Paragraph("In water works practice, <b>disinfection ≡ chlorination</b>.", body))
story.append(Spacer(1, 0.3*cm))

# 4a: Action
story.append(Paragraph("4a. Action of Chlorine", h2))
story.append(HRFlowable(width="100%", thickness=1, color=ACCENT))
story.append(Spacer(1, 0.2*cm))
story.append(Paragraph("When chlorine is added to water:", body))
story.append(info_box([
    Paragraph("<b>H₂O + Cl₂ → HCl + HOCl</b> &nbsp;&nbsp; (hypochlorous acid)", key_box),
    Paragraph("<b>HOCl → H⁺ + OCl⁻</b> &nbsp;&nbsp; (ionizes to hypochlorite ion)", key_box),
], bg=LIGHT_TEAL))
story.append(Spacer(1, 0.2*cm))

action_rows = [
    ["HCl (Hydrochloric acid)", "Neutralized by the alkalinity of water – no disinfecting action"],
    ["HOCl (Hypochlorous acid)", "MAIN disinfecting agent. 70–80 times more effective than OCl⁻. Predominates at pH 7"],
    ["OCl⁻ (Hypochlorite ion)", "Minor disinfecting action. Predominates at pH > 8.5 (where HOCl is 90% ionized → chlorine unreliable as disinfectant)"],
]
story.append(make_table(["Compound", "Role"], action_rows, [6*cm, 11*cm]))
story.append(Spacer(1, 0.2*cm))
story.append(bp(f"Chlorine works {bold('best')} when pH is around 7 (HOCl predominates)"))
story.append(bp(f"Chlorine is {bold('unreliable')} as disinfectant when pH > 8.5"))
story.append(bp(f"Water should have pH {bold('6–7.5')} for best results"))
story.append(Spacer(1, 0.2*cm))
story.append(Paragraph("<b>Secondary properties of chlorine:</b>", h3))
secondary = [
    "Oxidizes iron, manganese, and hydrogen sulphide",
    "Destroys some taste and odour-producing constituents",
    "Controls algae and slime organisms",
    "Aids coagulation",
]
for s in secondary:
    story.append(bp(s))
story.append(Spacer(1, 0.2*cm))
story.append(info_box([
    Paragraph("&#x26A0; Chlorine kills pathogenic bacteria but has <b>NO effect on spores, protozoal cysts, and helminthic ova</b> – except in higher doses. Certain viruses (polio, viral hepatitis) also resistant.", key_box),
], bg=LIGHT_RED, border=colors.HexColor("#cc0000")))
story.append(Spacer(1, 0.3*cm))

# 4b: Principles
story.append(Paragraph("4b. Principles of Chlorination", h2))
story.append(HRFlowable(width="100%", thickness=1, color=ACCENT))
story.append(Spacer(1, 0.2*cm))
principles = [
    ("Water must be clear", "Turbidity impedes efficient chlorination – turbid/polluted water is NOT suitable for direct chlorination"),
    ("Estimate chlorine demand", "Chlorine demand = Amount of chlorine added MINUS residual chlorine after 60 min contact. It is the chlorine needed to destroy bacteria and oxidize organic matter and ammoniacal substances."),
    ("Contact period", "Free residual chlorine must be present for at least <b>1 hour</b> to kill bacteria and viruses"),
    ("Free residual chlorine", "Minimum recommended: <b>0.5 mg/litre</b> (0.5 ppm) at end of 1 hour contact. Provides safety margin against recontamination."),
    ("Correct dose", "Correct dose = Chlorine demand + Free residual chlorine (0.5 mg/L)"),
]
for title, detail in principles:
    story.append(bp(f"{bold(title)}: {detail}"))
story.append(Spacer(1, 0.2*cm))
story.append(info_box([
    Paragraph("&#x2605; <b>Breakpoint:</b> The point at which the chlorine demand of the water is fully met. Adding chlorine beyond the breakpoint causes free chlorine (HOCl and OCl⁻) to appear in the water.", key_box),
], bg=LIGHT_YELLOW, border=colors.HexColor("#cc9900")))
story.append(Spacer(1, 0.3*cm))

# 4c: Methods
story.append(Paragraph("4c. Methods of Chlorination (Large-Scale)", h2))
story.append(HRFlowable(width="100%", thickness=1, color=ACCENT))
story.append(Spacer(1, 0.2*cm))
methods = [
    ["Chlorine gas", "Most widely used for large water works. Applied using chlorinators. Very effective."],
    ["Chloramine", "Formed by combining chlorine with ammonia. More stable. Residual protection lasts longer. Less taste/odour. Used where long distribution lines exist."],
    ["Perchloron (HTH)", "High Test Hypochlorite – 60–70% available chlorine. More stable than bleaching powder. Used where chlorine gas is not available."],
]
story.append(make_table(["Method", "Details"], methods, [4*cm, 13*cm]))
story.append(Spacer(1, 0.3*cm))

# 4d: Breakpoint
story.append(Paragraph("4d. Breakpoint Chlorination", h2))
story.append(HRFlowable(width="100%", thickness=1, color=ACCENT))
story.append(Spacer(1, 0.2*cm))
story.append(Paragraph("Breakpoint chlorination is the process of adding sufficient chlorine to water to satisfy the chlorine demand completely and produce a free residual chlorine. After the breakpoint:", body))
story.append(bp("All organic matter and ammoniacal compounds are oxidized"))
story.append(bp("All combined chlorine (chloramines) are destroyed"))
story.append(bp("Further additions of chlorine produce proportional increase in free residual chlorine"))
story.append(Spacer(1, 0.3*cm))

# 4e: Superchlorination
story.append(Paragraph("4e. Superchlorination and Dechlorination", h2))
story.append(HRFlowable(width="100%", thickness=1, color=ACCENT))
story.append(Spacer(1, 0.2*cm))
story.append(bp(f"{bold('Superchlorination')}: Adding chlorine in doses far in excess of chlorine demand (up to 5–10 mg/L). Used in emergencies and military operations."))
story.append(bp(f"{bold('Dechlorination')}: Removal of excess chlorine before supply to consumers, using sodium thiosulphate, sulphur dioxide, or activated carbon."))
story.append(PageBreak())

# ─── SECTION 5: HOUSEHOLD PURIFICATION ───────────────────────────────────────
story.append(section_header("5. HOUSEHOLD / INDIVIDUAL WATER PURIFICATION"))
story.append(Spacer(1, 0.3*cm))
story.append(Paragraph("Three methods are available for purifying water on an individual/domestic scale. These can be used singly or in combination:", body))
story.append(Spacer(1, 0.2*cm))

# 5a: Boiling
story.append(Paragraph("5a. Boiling", h2))
story.append(HRFlowable(width="100%", thickness=1, color=ACCENT))
story.append(Spacer(1, 0.2*cm))
story.append(info_box([
    Paragraph("Boiling is a <b>satisfactory method</b> for household water purification.", key_box),
    Paragraph("&#x2022; Water must be brought to a <b>rolling boil for 10–20 minutes</b>", key_box),
    Paragraph("&#x2022; Kills ALL bacteria, spores, cysts, and ova → yields <b>sterilized water</b>", key_box),
    Paragraph("&#x2022; Also removes <b>temporary hardness</b> (drives off CO₂, precipitates CaCO₃)", key_box),
    Paragraph("&#x2022; Taste is altered (harmless)", key_box),
    Paragraph("&#x2022; Offers <b>NO residual protection</b> against subsequent microbial contamination", key_box),
    Paragraph("&#x2022; Water should be boiled in the same container in which it will be stored", key_box),
]))
story.append(Spacer(1, 0.3*cm))

# 5b: Chemical Disinfection
story.append(Paragraph("5b. Chemical Disinfection", h2))
story.append(HRFlowable(width="100%", thickness=1, color=ACCENT))
story.append(Spacer(1, 0.2*cm))
chem_rows = [
    ["Bleaching powder\n(CaOCl₂)", "White amorphous powder, pungent smell. Contains ~33% available chlorine when fresh. Unstable – loses chlorine on exposure to air, light, moisture. Store in dark, cool, dry place. 'Stabilized bleach' = mixed with excess lime."],
    ["Chlorine solution", "Prepared from bleaching powder. 4 kg BP (25% available Cl) + 20L water = 5% chlorine solution. Subject to losses on exposure to light or prolonged storage."],
    ["HTH (Perchloron)\nHigh Test Hypochlorite", "Calcium compound. Contains 60–70% available chlorine. More stable than bleaching powder. Used in field conditions."],
    ["Chlorine tablets\n(Halazone tablets)", "Available under various trade names. Good for disinfecting small quantities. New NEERI tablet: 1 tablet (0.5 g) sufficient for 20 litres of water. 15x more effective than ordinary halogen tablets."],
    ["Iodine", "For emergency disinfection. 2 drops of 2% ethanol solution of iodine per 1 litre of clear water. Contact time: 20–30 minutes. Does not react with ammonia/organic compounds → stays in active form."],
    ["KMnO₄\n(Potassium Permanganate)", "Used for disinfecting wells. Oxidizing agent. Also helps in removing iron from water. Pink-purple colour at doses used."],
]
story.append(make_table(["Agent", "Details"], chem_rows, [4.5*cm, 12.5*cm]))
story.append(Spacer(1, 0.2*cm))
story.append(info_box([
    Paragraph("&#x2605; <b>Principle of chlorination for household water:</b> Ensure a free residual chlorine of <b>0.5 mg/litre at the end of 1 hour contact</b>.", key_box),
    Paragraph("&#x26A0; Highly polluted and turbid waters are <b>NOT suited for direct chlorination</b> – filter first.", key_box),
]))
story.append(Spacer(1, 0.3*cm))

# 5c: Filtration candles
story.append(Paragraph("5c. Filtration Candles", h2))
story.append(HRFlowable(width="100%", thickness=1, color=ACCENT))
story.append(Spacer(1, 0.2*cm))
story.append(bp("Household filters using unglazed ceramic or diatomaceous earth candles"))
story.append(bp("Examples: Berkefeld filter (kieselguhr), Pasteur-Chamberland filter (porcelain), Katadyn filter (ceramic with silver)"))
story.append(bp("Remove bacteria by mechanical filtration and adsorption"))
story.append(bp("Silver in Katadyn filter is oligodynamic – kills bacteria by releasing silver ions"))
story.append(bp("Must be regularly cleaned by scrubbing; boiled periodically to sterilize"))
story.append(PageBreak())

# ─── SECTION 6: KEY NUMBERS & EXAM FACTS ─────────────────────────────────────
story.append(section_header("6. KEY NUMBERS & EXAM FACTS"))
story.append(Spacer(1, 0.3*cm))

key_data = [
    ["TOPIC", "KEY FACT / NUMBER"],
    ["Slow sand filter – first used", "1804, Scotland"],
    ["Rapid sand filter – first used", "1885, USA"],
    ["Slow sand filter – sand grain size", "0.2–0.3 mm (effective diameter)"],
    ["Rapid sand filter – sand grain size", "0.4–0.7 mm"],
    ["Slow sand filter – rate", "0.1–0.4 m³/hr/m²   (2–3 m.g.a.d.)"],
    ["Rapid sand filter – rate", "5–15 m³/hr/m²   (200 m.g.a.d.) – 40–50x faster"],
    ["Bacteria removal – slow sand", "99.9–99.99%"],
    ["Bacteria removal – rapid sand", "98–99%"],
    ["Supernatant water depth (both filters)", "1.0–1.5 m"],
    ["Sand bed thickness", "~1.0–1.2 m"],
    ["Gravel support depth", "30–40 cm"],
    ["Surface area of 1 m³ filter sand", "15,000 m²"],
    ["Vital layer (Schmutzdecke) depth", "2–3 cm into top of sand bed"],
    ["Slow sand filter cleaning interval", "Every 4–6 weeks (summer); 2–3 months (winter)"],
    ["Backwashing time (rapid sand)", "~15 minutes"],
    ["Optimum storage period for river water", "10–14 days"],
    ["Bacterial drop during storage (5–7 days)", "~90%"],
    ["Free residual chlorine (minimum)", "0.5 mg/litre (0.5 ppm)"],
    ["Contact time for chlorination", "At least 1 hour"],
    ["Best pH for chlorination", "6.0–7.5 (chlorine unreliable above 8.5)"],
    ["HOCl vs OCl⁻ effectiveness", "HOCl is 70–80x more effective than OCl⁻"],
    ["Bleaching powder – available chlorine", "~33% (fresh); 25% commonly used"],
    ["HTH (Perchloron) – available chlorine", "60–70%"],
    ["Alum dose for coagulation", "5–40 mg/litre"],
    ["Boiling duration", "Rolling boil for 10–20 minutes"],
    ["Iodine for emergency disinfection", "2 drops of 2% iodine/litre; 20–30 min contact"],
    ["Chlorine tablet (NEERI)", "0.5 g tablet = 20 litres of water"],
    ["HTH preparation dose", "4 kg BP (25% Cl) + 20L water = 5% chlorine solution"],
]
key_table = Table(
    [[Paragraph(str(r[0]), ParagraphStyle("KH", parent=styles["Normal"], fontSize=9, fontName="Helvetica-Bold", textColor=DARK_TEAL, leading=12)),
      Paragraph(str(r[1]), ParagraphStyle("KV", parent=styles["Normal"], fontSize=9, fontName="Helvetica", leading=12))]
     for r in key_data],
    colWidths=[7*cm, 10*cm],
    repeatRows=1
)
key_table.setStyle(TableStyle([
    ("BACKGROUND", (0,0), (-1,0), TEAL),
    ("TEXTCOLOR", (0,0), (-1,0), colors.white),
    ("FONTNAME", (0,0), (-1,0), "Helvetica-Bold"),
    ("FONTSIZE", (0,0), (-1,0), 9.5),
    ("GRID", (0,0), (-1,-1), 0.5, colors.HexColor("#b0d8d8")),
    ("ROWBACKGROUNDS", (0,1), (-1,-1), [colors.white, LIGHT_TEAL]),
    ("TOPPADDING", (0,0), (-1,-1), 5),
    ("BOTTOMPADDING", (0,0), (-1,-1), 5),
    ("LEFTPADDING", (0,0), (-1,-1), 6),
    ("RIGHTPADDING", (0,0), (-1,-1), 6),
    ("VALIGN", (0,0), (-1,-1), "MIDDLE"),
]))
story.append(key_table)
story.append(Spacer(1, 0.3*cm))

# Mnemonic box
story.append(info_box([
    Paragraph("&#x1F4A1; <b>MNEMONIC – Slow Sand Filter elements: 'S-SUF'</b>", key_box),
    Paragraph("<b>S</b>upernatant water &nbsp; | &nbsp; <b>S</b>and bed (with Schmutzdecke) &nbsp; | &nbsp; <b>U</b>nder-drainage system &nbsp; | &nbsp; <b>F</b>ilter control valves", key_box),
    Paragraph("&#x1F4A1; <b>MNEMONIC – Stages of water treatment: 'SFD'</b>", key_box),
    Paragraph("<b>S</b>torage → <b>F</b>iltration → <b>D</b>isinfection", key_box),
    Paragraph("&#x1F4A1; <b>MNEMONIC – Rapid sand filter steps: 'CoRMFSBW'</b>", key_box),
    Paragraph("<b>Co</b>agulation → <b>R</b>apid mixing → <b>M</b>ixing/Flocculation → <b>F</b>locculation → <b>S</b>edimentation → <b>F</b>iltration → <b>B</b>ackwash (cleaning)", key_box),
], bg=LIGHT_YELLOW, border=colors.HexColor("#cc9900")))
story.append(Spacer(1, 0.3*cm))

# Footer
story.append(HRFlowable(width="100%", thickness=1, color=ACCENT))
story.append(Spacer(1, 0.2*cm))
story.append(Paragraph("Source: Park's Textbook of Preventive and Social Medicine | Generated by Orris Medical Library", source))
story.append(Paragraph("For exam preparation only. Verify all values against your primary textbook.", source))

doc.build(story)
print("PDF created:", OUTPUT)

cd /home/daytona/workspace/water-treatment-notes && python generate_pdf.py 2>&1

~/water-treatment-notes/generate_pdf.py

Error: String not found in file: '    Paragraph("&#x2022; Slimy, gelatinous layer extending <b>2–3 cm</b> into the top of the sand bed", key_box),
    Paragraph("&#x2022; Formation process = <b>'Ripening'</b> of the filter (takes several days to form fully)", key_box),
    Paragraph("&#x2022; Until fully formed, the first few days' filtrate is run to <b>WASTE</b>", key_box),
], bg=LIGHT_YELLOW, border=colors.HexColor("#cc9900")))'

python3 -c " with open('/home/daytona/workspace/water-treatment-notes/generate_p…

python3 -c " with open('/home/daytona/workspace/water-treatment-notes/generate_p…

python3 -c " with open('/home/daytona/workspace/water-treatment-notes/generate_p…

cd /home/daytona/workspace/water-treatment-notes && python generate_pdf.py 2>&1

ls -lh /home/daytona/workspace/water-treatment-notes/Water_Treatment_Methods_PSM…

You are building a PSM (Preventive and Social Medicine) exam preparation PDF for a medical student. The student's finals are in 20 days and they need compact but complete notes on 16 communicable diseases, structured exactly as their exam questions ask. ## YOUR TASK 1. Read the relevant sections from Park's Textbook of Preventive and Social Medicine (file paths given below) 2. Extract content for EXACTLY the sub-headings asked (listed per disease) 3. Build a well-formatted PDF using reportlab ## FILE LOCATIONS (all in Park's Textbook) - TB: /textbooks/9789382219163/9789382219163_block3.md around line 2746 - Polio: /textbooks/9789382219163/9789382219163_block3.md around line 5439 - Cholera: /textbooks/9789382219163/9789382219163_block4.md around line 995 - Typhoid: /textbooks/9789382219163/9789382219163_block4.md around line 1485 - Malaria: /textbooks/9789382219163/9789382219163_block4.md around line 3341 - Dengue: /textbooks/9789382219163/9789382219163_block4.md around line 2972 - Filariasis: /textbooks/9789382219163/9789382219163_block4.md around line 4632 - Rabies: /textbooks/9789382219163/9789382219163_block4.md around line 5390 - Leprosy: /textbooks/9789382219163/9789382219163_block5.md around line 1532 - Tetanus: /textbooks/9789382219163/9789382219163_block5.md around line 1218 - Influenza: /textbooks/9789382219163/9789382219163_block2.md around line 6374 - Kala Azar: /textbooks/9789382219163/9789382219163_block6.md around line 4413 - For Hepatitis B, Food Poisoning, Japanese Encephalitis, HIV/AIDS, STIs: search using query_library_db with: SELECT title, '/textbooks/' || block_file_path AS file_path, line_number, para_line_ranges FROM headings_fts WHERE book_title LIKE '%Park%' AND headings_fts MATCH '[topic]' ORDER BY rank LIMIT 5 ## EXACT QUESTIONS ASKED (structure your PDF exactly this way) **1. TUBERCULOSIS** - a) Epidemiology And Epidemiological Indices (incidence, prevalence, ARTI, case detection rate) - B) Tuberculin And Mantoux Test (0.1ml of 5TU PPD - how it is done, reading, interpretation) - C) Screening And Diagnostic Modalities (sputum AFB, CBNAAT, chest X-ray, IGRA) - D) Prevention And Control / Anti-Tubercular Therapy (RNTCP/NTEP regimens: intensive + continuation phase, Category I/II, drugs - HRZE, DOT) **2. POLIOMYELITIS** - A) Epidemiology (agent, host, environment; type 1/2/3; endemic/epidemic; India eliminated 2014) - B) Diagnosis And Clinical Presentation (abortive, non-paralytic, paralytic; AFP surveillance) - C) Management Vaccines (OPV - Sabin, IPV - Salk; differences; schedule; VAPP; NPSP) **3. CHOLERA** - A) Epidemiology (El Tor biotype, O139, transmission, incubation, rice-water stools) - B) Strategy For Control Of Cholera Outbreak In A Village (step-by-step: case notification, ORS, water chlorination, quarantine, vaccination, health education) - C) Immunization, Prevention And Control **4. TYPHOID FEVER** - A) Epidemiology (Salmonella typhi, paratyphi, incubation, source, transmission) - B) Laboratory Diagnosis (Widal test, blood culture gold standard, bone marrow culture, stool/urine culture, Typhidot) - C) Immunization, Prevention And Control (Vi polysaccharide vaccine, Ty21a oral vaccine, hygiene, water purification) **5. HEPATITIS B** - A) Problem Statement (global burden, India endemic category, carrier state 3-5%) - B) Epidemiology (HBV, vertical/horizontal/sexual/IVDU transmission, incubation 45-180 days) - C) Immunization, Prevention And Control (HepB vaccine schedule: 0-1-6 months; universal infant vaccination; HBsAg screening in pregnancy; HBIG for neonates of HBsAg positive mothers) **6. FOOD POISONING** - Types (bacterial: Staph aureus, Salmonella, Clostridium botulinum, Cl. perfringens, B. cereus; chemical; plant/animal toxins) - Investigation of an outbreak (define case, active case finding, epidemiological investigation, food history, lab samples - stool, vomit, food, water, blood) - Prevention And Control (food hygiene, cold chain, safe water, reporting) **7. MALARIA** - B) Epidemiology (Plasmodium: falciparum, vivax, malariae, ovale; Anopheles vector; India burden) - C) Life Cycle (sporogony in mosquito, schizogony in human - liver stage + blood stage; P. vivax/ovale hypnozoites) - D) Malarial Indices: API (Annual Parasitic Incidence), SPR, SFR, ABER, slide positivity rate, API <1 = low endemicity - E) Prevention And Control / IVM (Integrated Vector Management: IRS with DDT/deltamethrin, ITNs, larviciding, biological control, chemoprophylaxis with chloroquine/doxycycline) - F) Malarial Vaccines (RTS,S - first approved; NVBDCP program) **8. LYMPHATIC FILARIASIS** - A) Epidemiology (Wuchereria bancrofti; Culex quinquefasciatus vector; nocturnal periodicity; India's burden) - B) Filarial Detection Tests (night blood smear; ICT card test; antigen detection; ELISA) - C) Filarial Indices (microfilaria rate, disease rate, endemicity index) - D) Prevention And Control (MDA with DEC + albendazole; vector control; NVBDCP) **9. DENGUE FEVER** - A) Epidemiology (DEN 1-4 serotypes; Aedes aegypti; urban; monsoon peak; India) - B) Clinical Types (dengue fever, dengue hemorrhagic fever DHF, dengue shock syndrome DSS; WHO classification 2009: dengue with/without warning signs, severe dengue) - C) Management Of Dengue Epidemic (surveillance, vector control, case management, NS1 antigen test, platelet monitoring) - D) Prevention And Control (NVBDCP; source reduction; no vaccine officially in national program) **10. JAPANESE ENCEPHALITIS** - A) Epidemiology (Flavivirus; Culex tritaeniorhynchus vector; piggeries + paddy fields; seasonal; UP, Bihar endemic) - B) Prevention And Control (surveillance, vector control, pig vaccination, human vaccine) - C) JE Vaccine (SA14-14-2 live attenuated; given at 9-12 months + booster; NVBDCP) **11. KALA AZAR (Leishmaniasis)** - A) Epidemiology (Leishmania donovani; Phlebotomus vector; Bihar, Jharkhand, UP, WB; PKDL) - B) Types & Clinical Features (visceral: fever, splenomegaly, cachexia; cutaneous; mucocutaneous; PKDL) - C) Prevention And Control (IRS with DDT; kala azar elimination program; miltefosine treatment; vector control) **12. RABIES** - A) Epidemiology (rhabdovirus; dog bites 97%; incubation 10 days to years; India highest burden) - B) Wound Treatment (categories 1/2/3; Category 3: thorough wound wash with soap + water 15 min, antirabies vaccine + HRIG) - C) Pre-Exposure Prophylaxis (PrEP: 3 doses on days 0, 7, 21/28; for vets, lab workers) - D) Post-Exposure Prophylaxis (PEP: 5 doses on days 0,3,7,14,28 Essen regimen OR 2-1-1 Zagreb; HRIG for Cat 3) - E) Vaccination (PCECV, HDCV, Purified Vero cell vaccine; intradermal regimen) **13. TETANUS** - Epidemiology (Clostridium tetani, soil-borne, wound entry, neonatal tetanus via unclean cord cutting) - Clinical Features (incubation 3-21 days; trismus/lockjaw, risus sardonicus, opisthotonos, spasms) - Preventive Measures (TT immunization schedule; wound management; tetanus toxoid; TTCV; clean delivery practices for neonatal tetanus) **14. LEPROSY** - A) Epidemiology (Mycobacterium leprae; long incubation 2-5 yrs; India highest burden; close contact transmission; elimination <1/10,000) - B) Classification (Ridley-Jopling: TT, BT, BB, BL, LL; WHO: PB = 1-5 lesions, MB = 6+ lesions) - C) Lepromin Test (Mitsuda reaction; positive in TT, negative in LL; not diagnostic, only indicates immune response) - D) Clinical Features (hypopigmented anesthetic patches, nerve thickening, deformities, disabilities) - E) Prevention And Control / NLEP (MDT regimen: PB = Dapsone + Rifampicin 6 months; MB = Dapsone + Rifampicin + Clofazimine 12 months; NLEP target: eliminate leprosy) **15. STIs + HIV/AIDS** - STIs list (syphilis, gonorrhea, chlamydia, genital herpes, HPV, trichomoniasis, chancroid, LGV) - Syndromic Management of RTI/STI (treat based on syndrome not lab: urethral discharge, vaginal discharge, genital ulcer, inguinal bubo) - HIV/AIDS: Epidemiology, Problem Statement (UNAIDS global; India 2.4 million; decline in new infections) - WHO Clinical Staging of HIV (Stage 1: asymptomatic; Stage 2: minor mucocutaneous; Stage 3: severe weight loss, TB; Stage 4: AIDS-defining: PCP, cryptococcal meningitis, CMV, toxoplasmosis) - HIV-TB Co-infection (TB is commonest OI in HIV; CPT; ART timing - start ART within 2 weeks if CD4 <50) - Chemoprophylaxis (Cotrimoxazole Preventive Therapy CPT; INH Preventive Therapy IPT) - NACO Program (National AIDS Control Organization; NACP I-IV; ART centers; ICTC; PPTCT; blood safety; harm reduction) **16. INFLUENZA** - A) Epidemiology (Influenza A/B/C; H and N antigens; pandemic strain H1N1 2009; droplet transmission; winter peak) - B) Antigenic Shift vs Drift (Shift: major change, new pandemic strain, new H or N, no immunity; Drift: minor change, seasonal epidemic, partial immunity) - C) Prevention And Control / Vaccines (annual trivalent/quadrivalent inactivated vaccine; oseltamivir for treatment/prophylaxis; hand hygiene; surveillance) ## INSTRUCTIONS FOR READING FILES Use read_file with offset and limit (100 lines at a time). For each disease, read ~150-200 lines from the stated starting line. Example: read_file(file_path="/textbooks/9789382219163/9789382219163_block3.md", offset=2746, limit=200) Read enough to get actual content for each sub-heading. If a section continues, read more. ## PDF REQUIREMENTS - Output file: /home/daytona/workspace/water-treatment-notes/PSM_Communicable_Diseases_Exam_Notes.pdf - Use reportlab (pre-installed) - Style: Compact but readable. A4 page. - Cover page with title "PSM FINALS — COMMUNICABLE DISEASES" and subtitle "Exam Preparation Notes | Structured as per Question Pattern" - Each disease gets its own clearly headed section - Sub-headings match the question headings exactly - Use tables where data is tabular (vaccines schedules, drug regimens, malarial indices) - Use bullet points for lists - Color scheme: dark blue headers, light blue/yellow info boxes, clean white background - At bottom of each section, add a small "KEY EXAM POINTS" box highlighting the most important numbers/facts - Font: Helvetica, body size 9-9.5, heading size 12-14 - All 16 diseases in ONE PDF ## IMPORTANT - Read the actual textbook content — do not rely solely on your training knowledge - For topics not found in Park's (like HepB, JE, HIV), search using query_library_db first - Keep content exam-focused: include key numbers, drug names, doses, schedules, indices - Be thorough but compact — no fluff, no long paragraphs if bullet points work better - After writing the Python script, execute it and confirm the PDF is created successfully Return: the exact file path of the created PDF, and a brief summary of what was included for each disease.

mkdir -p /home/daytona/workspace/water-treatment-notes && ls /home/daytona/works…

You are building a PSM (Preventive and Social Medicine) exam preparation PDF for a medical student with finals in 20 days. Build compact but complete notes on 16 communicable diseases, structured exactly as exam questions ask. ## YOUR TASK 1. Read relevant sections from Park's Textbook of Preventive and Social Medicine 2. Extract content for EXACTLY the sub-headings asked per disease 3. Build a well-formatted PDF using reportlab ## STEP 1 — FIND CONTENT (use query_library_db AND read_file) First run these searches to find exact file locations: ```sql SELECT title, '/textbooks/' || block_file_path AS file_path, line_number, para_line_ranges FROM headings_fts WHERE book_title LIKE '%Park%' AND headings_fts MATCH 'TUBERCULOSIS' ORDER BY rank LIMIT 3 ``` Do similar searches for: POLIOMYELITIS, CHOLERA, TYPHOID, HEPATITIS, FOOD POISONING, MALARIA, FILARIASIS, DENGUE, JAPANESE ENCEPHALITIS, KALA AZAR, RABIES, TETANUS, LEPROSY, HIV AIDS, INFLUENZA Known starting locations in Park's (block file paths): - TB: /textbooks/9789382219163/9789382219163_block3.md line ~2746 - Polio: /textbooks/9789382219163/9789382219163_block3.md line ~5439 - Cholera: /textbooks/9789382219163/9789382219163_block4.md line ~995 - Typhoid: /textbooks/9789382219163/9789382219163_block4.md line ~1485 - Malaria: /textbooks/9789382219163/9789382219163_block4.md line ~3341 - Dengue: /textbooks/9789382219163/9789382219163_block4.md line ~2972 - Filariasis: /textbooks/9789382219163/9789382219163_block4.md line ~4632 - Rabies: /textbooks/9789382219163/9789382219163_block4.md line ~5390 - Leprosy: /textbooks/9789382219163/9789382219163_block5.md line ~1532 - Tetanus: /textbooks/9789382219163/9789382219163_block5.md line ~1218 - Influenza: /textbooks/9789382219163/9789382219163_block2.md line ~6374 - Kala Azar: /textbooks/9789382219163/9789382219163_block6.md line ~4413 For Hepatitis B, Japanese Encephalitis, HIV/AIDS, Food Poisoning — search using: ```sql SELECT title, '/textbooks/' || block_file_path AS file_path, line_number, para_line_ranges FROM headings_fts WHERE book_title LIKE '%Park%' AND headings_fts MATCH 'HEPATITIS' ORDER BY rank LIMIT 5 ``` Read ~150-200 lines per disease starting from those line numbers. ## STEP 2 — EXACT CONTENT TO COVER PER DISEASE **1. TUBERCULOSIS** ★★★★★★★ - Epidemiology & Epidemiological Indices (ARTI, incidence, prevalence, case notification rate) - Tuberculin & Mantoux Test (0.1ml of 5TU PPD intradermal; reading at 48-72h; >10mm positive; significance) - Screening & Diagnostic Modalities (sputum smear, CBNAAT/GeneXpert, chest X-ray, IGRA) - Prevention & Control / ATT (RNTCP/NTEP; drug regimens: HRZE intensive + HR continuation; DOT; new regimens) **2. POLIOMYELITIS** ★★★ - Epidemiology (3 serotypes; wild poliovirus; faecal-oral; India eliminated in 2014) - Diagnosis & Clinical Presentation (4 forms: inapparent, abortive, non-paralytic, paralytic; AFP surveillance) - OPV vs IPV (Sabin vs Salk; OPV: live attenuated, oral, cheap, herd immunity, VAPP risk; IPV: killed, injectable, no VAPP; schedule; NPSP) **3. CHOLERA** ★★★ - Epidemiology (V. cholerae O1/O139; El Tor; rice-water stools; incubation 6h-5days; fecal-oral) - Control of Cholera Outbreak in a Village (step-by-step: notification, ORS, water chlorination, case isolation, contacts, vaccination, health education, food safety) - Immunization, Prevention & Control (OCV: Shanchol; ORS treatment; water purification; WASH) **4. TYPHOID FEVER** ★★★★★★ - Epidemiology (S. typhi, paratyphi A/B/C; incubation 1-3 weeks; chronic carriers; food/water) - Laboratory Diagnosis (Widal test – titre rise; blood culture GOLD STANDARD; bone marrow culture most sensitive; stool/urine; Typhidot IgM; TUBEX) - Immunization, Prevention & Control (Vi polysaccharide IM 2yrs+; Ty21a oral; hygiene; water; carrier treatment) **5. HEPATITIS B** ★★★★★ - Problem Statement (global: 257 million chronic; India: intermediate endemic 2-8% HBsAg; 40 million carriers) - Epidemiology (HBV; vertical transmission most important in India; sexual; IVDU; blood; incubation 45-180 days; HBsAg, HBeAg, anti-HBs markers) - Immunization & Prevention (HepB vaccine: 3 doses 0-1-6 months; universal infant vaccination birth dose; HBIG 0.06ml/kg for neonate of HBsAg+ mother within 12h; blood safety; needle precautions) **6. FOOD POISONING** ★★★ - Types of Food Poisoning: * Bacterial: Staphylococcus aureus (toxin, 1-6h, vomiting), Salmonella (6-48h, diarrhea, fever), Cl. botulinum (12-36h, neuroparalytic), Cl. perfringens (8-22h), B. cereus (emetic/diarrheal) * Chemical: heavy metals, pesticides * Plant/animal toxins - Investigation of Food Poisoning Outbreak (define case, line listing, food history, attack rate by food item, collect samples: stool/vomit/food/water, epidemiological analysis) - Prevention & Control (food hygiene 5 keys of food safety, cold chain, safe water, reporting to health authorities) **7. MALARIA** ★★★★ - Epidemiology (4 species; P. falciparum most dangerous – severe malaria, cerebral malaria; India burden) - Life Cycle (human: pre-erythrocytic liver stage → erythrocytic blood stage → gametocytes; mosquito: sporogony; hypnozoites in P. vivax/ovale) - Malarial Indices (API: Annual Parasitic Incidence = positive slides per 1000 population per year; ABER, SPR, SFR; API <1 low, 1-2 moderate, >2 high endemicity) - Prevention & Control / IVM (Integrated Vector Management: IRS with insecticides, ITNs/LLINs, larviciding, biological control with Gambusia fish; chemoprophylaxis: chloroquine weekly, doxycycline; NVBDCP) - Malarial Vaccines (RTS,S Mosquirix – first WHO approved 2021; R21 approved 2023) **8. LYMPHATIC FILARIASIS** ★★★ - Epidemiology (Wuchereria bancrofti; Culex quinquefasciatus vector; nocturnal periodicity; microfilaremia; India 17 endemic states) - Filarial Detection Tests (night blood smear at 10pm-2am; ICT card test for antigen; ELISA; Og4C3 antigen test) - Filarial Indices (microfilaria rate, disease rate, endemicity index) - Prevention & Control (MDA: DEC 6mg/kg + albendazole 400mg annually; morbidity management; NVBDCP; triple drug therapy DEC+Alb+Ivermectin) **9. DENGUE FEVER** ★★★★ - Epidemiology (4 serotypes DEN1-4; Aedes aegypti; urban/semi-urban; daytime biting; India endemic; secondary infection → DHF) - Clinical Types & Features (Classic dengue fever; DHF: hemorrhage + thrombocytopenia + plasma leak; DSS; WHO 2009: dengue ± warning signs, severe dengue; warning signs: abdominal pain, persistent vomiting, bleeding, rapid breathing) - Management of Dengue Epidemic (NS1 antigen, IgM/IgG ELISA; platelet monitoring; supportive treatment; no specific antivirals; epidemic response: vector control, surveillance) - Prevention & Control (NVBDCP; Aedes breeding site elimination: empty stagnant water; no vaccine in NP; Dengvaxia issues) **10. JAPANESE ENCEPHALITIS** ★★★★ - Epidemiology (Flavivirus; Culex tritaeniorhynchus vector; pig amplifying host; paddy fields; seasonal Aug-Oct; UP, Bihar, Assam endemic; case fatality 20-30%) - Prevention & Control (vector control: IRS, larviciding; pig vaccination; human JE vaccination; surveillance) - JE Vaccine (SA 14-14-2 live attenuated; 0.5ml SC; given at 9-12 months under UIP; booster at 16-24 months in endemic areas; NVBDCP; also inactivated Vero cell vaccine) **11. KALA AZAR (Leishmaniasis)** ★★★ - Epidemiology (L. donovani; Phlebotomus argentipes sandfly vector; Bihar, Jharkhand, UP, West Bengal; PKDL; elimination target <1/10,000) - Types & Clinical Features (Visceral: insidious fever, splenomegaly, hepatomegaly, pancytopenia, cachexia, hyperpigmentation "kala=black"; Cutaneous; Mucocutaneous; PKDL: post-kala-azar dermal leishmaniasis) - Prevention & Control (IRS with DDT; sandfly control; miltefosine oral; liposomal amphotericin B; kala azar elimination programme India; rK39 rapid test for diagnosis) **12. RABIES** ★★★★ - Epidemiology (Rhabdovirus; zoonosis; dog bites 97% in India; incubation 10 days to 1 year; Negri bodies in brain; fatal once symptoms start; India: 20,000 deaths/year) - Wound Treatment (Category I: licking intact skin – no treatment; Category II: nibbling, minor scratches – wash + vaccine; Category III: deep bite, mucous membrane contact – wash + vaccine + HRIG; Wound wash: soap+water 15 min + betadine) - Pre-Exposure Prophylaxis (3 doses on days 0, 7, 21 or 28; for vets, lab workers, travelers) - Post-Exposure Prophylaxis (Essen: 5 doses days 0,3,7,14,28; Zagreb: 2-1-1 on days 0,7,21; HRIG 20 IU/kg for Cat 3 – infiltrate wound + IM) - Vaccines (PCECV, HDCV, PVRV; intradermal regimens available; rabies immunoglobulin: HRIG/ERIG) **13. TETANUS** ★★★★ - Epidemiology (Cl. tetani; gram +ve anaerobe; spores in soil; tetanospasmin toxin; neonatal tetanus via unclean cord; incubation 3-21 days, usually 7-10 days) - Clinical Features (trismus/lockjaw first sign; risus sardonicus; opisthotonos; spasms; autonomic dysfunction; Severity: Grade 1-4; case fatality high) - Preventive Measures (TT immunization: 2 doses + booster in pregnancy; pentavalent vaccine in children; wound management: debridement + TIG + TT; clean delivery for neonatal tetanus prevention) **14. LEPROSY** ★★★ - Epidemiology (M. leprae; slowest growing bacillus; incubation 2-5 years; India eliminated at national level <1/10,000 but pockets remain; droplet + prolonged contact) - Classification: * Ridley-Jopling: TT (tuberculoid) → BT → BB → BL → LL (lepromatous) on immunity spectrum * WHO: PB (paucibacillary) = 1-5 lesions; MB (multibacillary) = 6+ lesions OR positive slit-skin smear - Lepromin Test (Mitsuda reaction at 3-4 weeks; positive in TT/BT – good cell-mediated immunity; negative in LL – poor CMI; NOT diagnostic, only indicates immune status) - Clinical Features (hypopigmented anaesthetic patch, thickened nerves – ulnar/radial cutaneous/common peroneal/great auricular, deformities, lagophthalmos, claw hand, foot drop) - Prevention & MDT / NLEP (PB-MDT: Rifampicin 600mg monthly + Dapsone 100mg daily × 6 months; MB-MDT: + Clofazimine 300mg monthly/50mg daily × 12 months; NLEP; Leprosy case definition; disability grading 0/1/2) **15. STIs + HIV/AIDS** ★★★★★★★★ - STIs List (syphilis, gonorrhoea, chlamydia, genital herpes HSV-2, HPV/genital warts, trichomoniasis, chancroid, LGV, donovanosis) - Syndromic Management RTI/STI (syndromes: urethral discharge → ciprofloxacin+doxycycline; vaginal discharge → metronidazole+fluconazole; genital ulcer → benzathine penicillin+acyclovir+ciprofloxacin; inguinal bubo → doxycycline; advantages: no lab needed, same day treatment) - HIV/AIDS Epidemiology & Problem Statement (UNAIDS: 39 million living with HIV; India: ~2.4 million; declining new infections; high risk groups: MSM, FSW, PWID, TG) - WHO Clinical Staging (Stage 1: asymptomatic/PGL; Stage 2: minor weight loss, herpes zoster, oral ulcers; Stage 3: >10% weight loss, chronic diarrhea, oral candidiasis, pulmonary TB; Stage 4/AIDS: PCP, cryptococcal meningitis, CMV retinitis, toxoplasmosis, MAC, Kaposi sarcoma) - HIV-TB Co-infection (TB is commonest OI; screen all TB patients for HIV; ART within 2 weeks of TB treatment if CD4 <50; CPT; IRIS) - Chemoprophylaxis (CPT: cotrimoxazole for all HIV+ with CD4 <200; IPT: isoniazid 300mg daily ×6 months for LTBI) - NACO Program (NACP phases I-IV; services: ART centers, ICTC/PPTCT, OST, TI projects, blood safety, condom promotion; 90-90-90 target) **16. INFLUENZA** ★★★ - Epidemiology (Influenza A, B, C; A most important; H1-18 subtypes, N1-11; H1N1 pandemic 2009; droplet; winter peak; elderly/children/pregnant vulnerable) - Antigenic Shift vs Drift: * DRIFT: minor gradual change in H or N antigen; due to point mutations; causes seasonal epidemics; partial immunity in population * SHIFT: major abrupt change; new H or N subtype (reassortment of 2 viruses); causes pandemic; no existing immunity; only Influenza A - Prevention & Control / Vaccines (trivalent/quadrivalent inactivated influenza vaccine; annual vaccination; recommended for elderly, pregnant, healthcare workers, children 6m-5y; oseltamivir (Tamiflu) for treatment within 48h; surveillance; IHR 2005 reporting) ## STEP 3 — BUILD PDF Output: /home/daytona/workspace/water-treatment-notes/PSM_Communicable_Diseases_Exam_Notes.pdf Use reportlab. Design requirements: - Cover page: dark navy blue banner "PSM FINALS — COMMUNICABLE DISEASES" subtitle "Exam Preparation Notes | Based on Park's Textbook of PSM" - Each disease = 1 section with colored header bar (alternating navy/dark teal) - Sub-headings in bold colored text matching the question letters (A, B, C, D...) - Bullet points for content — NO long paragraphs - KEY EXAM POINTS box at end of each disease (yellow background) — highlight the most testable numbers/facts - Tables for: vaccine schedules, drug regimens, comparison tables (OPV vs IPV, Antigenic shift vs drift, malarial indices, etc.) - Star ratings shown (★★★★★★★) indicating exam importance - A4 page, compact margins, Helvetica font, body 9pt, headings 11-12pt - Page numbers - ALL 16 diseases in ONE PDF ## IMPORTANT NOTES - The goal is compact exam notes — bullets preferred over prose - Include actual numbers: doses, durations, incubation periods, indices - Drug regimens must be accurate: HRZE, MDT regimens, ART, vaccine schedules - After writing the script, execute it with: execute(command="python /home/daytona/workspace/water-treatment-notes/generate_cd_pdf.py") - Fix any errors and re-run until PDF is created - Verify file exists with: execute(command="ls -lh /home/daytona/workspace/water-treatment-notes/") RETURN: The exact output file path + confirmation that all 16 diseases are covered.

ls /home/daytona/workspace/ 2>/dev/null || mkdir -p /home/daytona/workspace/wate…

python3 -c "import reportlab; print(reportlab.Version)"