Chemical Solutions for Effective and Safe Residential Water and Wastewater Treatment

Introduction

Water quality in a residential environment plays an important role in maintaining the health and hygiene of daily life. Both clean water and wastewater need to go through a proper treatment process so that they are safe to use and do not pollute the environment. One of the most effective ways to maintain water quality is through the use of chemical solutions (chemicals) specifically designed for the treatment of clean water and household wastewater.

1. Household Clean Water Treatment

Clean water for households can come from PDAM, boreholes, or rainwater harvesting. However, it often contains iron (Fe), manganese (Mn), odor, or high turbidity. To overcome this, several chemicals can be used in the water treatment process, including:

a. Coagulation and Flocculation

Materials such as aluminum sulfate (alum) or PAC (Poly Aluminum Chloride) function to bind fine particles and precipitate them. This process makes the water clearer and easier to filter.

b. Neutralization of pH

The use of quicklime (CaO) or soda ash (Na₂CO₃) can stabilize the acidity of water so that it does not damage pipes and household appliances.

c. Disinfection

The next important stage is the killing of microbes using materials such as chlorine (NaOCl), hydrogen peroxide (H₂O₂), or with UV and ozone systems.
Disinfection ensures water is free of harmful bacteria, viruses and germs before consumption.

d. Iron and Manganese Removal

For water containing high levels of metals, potassium permanganate (KMnO₄) is used to oxidize Fe²⁺ and Mn²⁺ into a solid precipitate that can be filtered.

e. Purification and Odor Removal

Activated carbon plays an important role in removing odor, taste, and color from water. It also helps absorb residual organic matter and dissolved chemicals.

2. Domestic Wastewater Treatment

Domestic wastewater or gray water and black water comes from the kitchen, bathroom, and toilet. If not treated properly, this waste can pollute the soil and water sources. The following chemicals are commonly used in the domestic waste treatment process:

a. Coagulation and Flocculation

Materials such as PAC, FeCl₃, and Fe₂(SO₄)₃ help settle suspended solids and oils before entering the biological process.

b. pH Neutralization

The use of NaOH, H₂SO₄, or lime helps stabilize the pH so that the decomposing bacteria in the biological reactor work optimally.

c. Biological Degradation

The use of bio-enzymes or decomposing bacteria (e.g. EM4, Bacillus sp.) can accelerate the decomposition of organic matter (BOD, COD) and reduce odors.
This method is safe, environmentally friendly, and suitable for modern septic tank systems.

d. Final Disinfection

Before the treated water is discharged into the environment, a final disinfection process is carried out using chlorine, hydrogen peroxide, or UV sterilizers to kill residual microbes.

e. Filter Polishing

The last stage uses activated carbon, zeolite, and silica sand to purify water to make it clear, odorless, and free of harmful substances.

3. General Residential Wastewater Treatment System

The following wastewater treatment flow is recommended for household scale:

1. Screening / Grease Trap - Filters out large solids and grease.

2. Equalization Tank - Stabilizes the discharge of wastewater flow.

3. Coagulation-Flocculation (PAC + Polymer) - Settles suspended impurities.

4. Biological Reactor (Anaerobic-Aerobic) - Decomposes organic matter naturally.

5. Secondary Sedimentation - Separates sludge from water.

6. Sand and Activated Carbon Filters - Purifies water.

7. Disinfection (Chlorine/UV) - Sterilizes the water before disposal.

All of these stages are intended so that the processed results meet the domestic wastewater quality standards according to Permen LHK No. 68 of 2016.

4. Example of Chemical Usage Dosage

The dosage can be adjusted according to water conditions, discharge, and laboratory test results.

5. Safety and Environmental Management

Use chemicals that have an official Safety Data Sheet (SDS).
Some important things that must be considered:

• Avoid mixing oxidizers and reductants (e.g. chlorine + bisulfite).

• Use personal protective equipment such as gloves and masks.

• Store chemicals in a cool, dry and separate place.

• Ensure that the treated water has the parameters:

  • BOD ≤ 30 mg/L

  • COD ≤ 100 mg/L

  • TSS ≤ 30 mg/L

  • pH 6-9

6. Product and Technology Recommendations for Household Scale

For small to medium housing, some ready-to-use solutions that are easily found in the market include:

• EM4, BioSeptik, EcoBio - Bacteria that decompose septic tank waste.

• PAC liquid or powder - For water purification.

• Chlorine tablets (TCCA 90%) - Clean water and pool disinfection.

• Activated carbon + zeolite + silica sand - Simple 3-layer filter.

• Mini ozone generator - Alternative disinfection without chemical residue.

Cover

The use of chemical solutions for residential water and waste treatment is an important step in maintaining environmental sustainability and occupant health. By choosing the right chemicals, appropriate dosage, and implementing the correct treatment system, household water can be reused or discharged without polluting the environment.

If you want to design a simple, efficient water treatment system for your home or housing complex, consulting with a water treatment expert or service provider will help ensure optimal results and environmental standards.