Waste Water Management-V1.0

8/8/2019 Waste Water Management-V1.0

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WASTE WATER MANAGEMENT

Definition of waste water

Wastewater is any water that has been adversely affected in quality by anthropogenic influence. Itcomprises liquid waste discharged by domestic residences, commercial properties, industry,and/or agriculture and can encompass a wide range of potential contaminants andconcentrations.

In the most common usage, it refers to the municipal wastewater that contains a broad spectrumof contaminants resulting from the mixing of wastewaters from different sources.Sewage is correctly the subset of wastewater that is contaminated with feces or urine, but is oftenused to mean any wastewater. "Sewage" includes domestic, municipal, or industrial liquid wasteproducts disposed of, usually via a pipe or sewer or similar structure, sometimes in a cesspoolemptier.This graphical representation clarifies the natural water storage and supply

Categories and Origin

There are few kinds of waste water which are categorized as follows:

• Human waste, usually from lavatories: (fæces, used toilet paper, wipes, urine, otherbodily fluids) also known as black water



• Cesspit leakage

• Septic tank discharge

• Sewage treatment plant discharge

• Washing water (personal, clothes, floors, dishes, etc.) also known as gray water orsullage

• Rainfall collected on roofs, yards, hard-standings, etc. (traces of oils and fuel but

generally clean)• Groundwater infiltrated into sewerage.

• Highway drainage (oil, de-icing agents, rubber residues)

• Storm drains (almost anything including cars, shopping trolleys, trees, cattle etc.)

• Black water - surface water contaminated by sewage

• Industrial waste: -

• Industrial site drainage (silt, sand, alkali, oil, chemical)o Industrial cooling waters (biocides, heat, slimes, silt)o Industrial process waterso Organic - biodegradable - includes waste from abattoirs and creameries and ice-

cream manufacture.o Organic - non bio-degradable or difficult to treat - for example Pharmaceutical or

Pesticide manufacturingo Inorganic - for example from the metalworking industryo Extreme pH - from acid/alkali manufacturing, metal platingo Toxic - e.g. from metal plating, cyanide production, pesticide manufacturingo Solids and Emulsions - e.g. Paper manufacturing, food stuffs, lubricating and

hydraulic oil manufacture

Wastewater constituents

The composition of wastewater varies widely. This is a partial list of what it may contain:

• Water (> 95%) which is often added during flushing to carry the waste down a drain

• Pathogens such as bacteria, viruses and parasitic worms.• Non-pathogenic bacteria (> 100,000 / ml for sewage)

• Organic particles such as faeces, hairs, food, vomit, paper fibers, plant material, humus,etc.

• Soluble organic material such as urea, fruit sugars, soluble proteins, drugs,pharmaceuticals, etc.

Oxidizable material + bacteria + nutrient + O2 → CO2 + H2O + oxidized inorganicsuch as NO3 or SO4

Oxygen consumption by reducing chemicals such as sulfides and nitrites is typified as follows:

S

--

+ 2 O2 →

SO4

--

NO2-+ ½ O2 → NO3

-

Since all natural waterways contain bacteria and nutrient, almost any waste compoundsintroduced into such waterways will initiate biochemical reactions (such as shown above). Thosebiochemical reactions create what is measured in the laboratory as the Biochemical oxygendemand (BOD).Oxidizable chemicals (such as reducing chemicals) introduced into a naturalwater will similarly initiate chemical reactions (such as shown above). Those chemical reactionscreate what is measured in the laboratory as the Chemical oxygen demand (COD).Both the BODand COD tests are a measure of the relative oxygen-depletion effect of a waste contaminant.

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Both have been widely adopted as a measure of pollution effect. The BOD test measures theoxygen demand of biodegradable pollutants whereas the COD test measures the oxygendemand of biogradable pollutants plus the oxygen demand of non-biodegradable oxidizablepollutants.

Here is an example of conventional Waste Water Treatment

Ecological Sanitation and its concepts

Ecological sanitation (Ecosan) is a new holistic paradigm in sanitation, which is based on an

overall view of material flows as part of an ecologically and economically sustainable wastewatermanagement system tailored to the needs of the users and to the respective local conditions. Itdoes not favor a specific sanitation technology, but is rather a new philosophy in handlingsubstances that have so far been seen simply as wastewater and water-carried waste fordisposal.

According to Esrey et al. (2003) ecological sanitation can be defined as a system that:

• Prevents disease and promotes health

• Protects the environment and conserves water

• Recovers and recycles nutrients and organic matter

Ecosan offers a flexible framework, where centralized elements can be combined with

decentralized ones, waterborne with dry sanitation, high-tech with low-tech, etc. By considering amuch larger range of options, optimal and economic solutions can be developed for eachparticular situation.

Arguments for the use of ecological sanitation

Often, water used in flush toilets is of drinking quality. Only 1% of global water is drinkable,therefore, it is a precious resource. Water fit to be drunk is being used for other purposes that canuse lesser quality water, such as toilets.

Mixing faeces and urine makes treatment difficult. All wastewater treatment plants use somenatural/biological processes, but nature does not normally have this wastewater, so there are no

microbes that can deal with this mix. In order to treat waste, treatment plants have to do this instages. Each stage treats a different component of the mix by creating the right environment formicrobes to do their work (aerobic, anaerobic, anoxic and the right pH). This is costly andrequires energy. Due to the complexity of the treatment process, treatment plants tend to belarge. This requires costly infrastructure to build and maintain it, often out of the reach of poorercommunities.



Industrial water treatment

Industrial Water Treatment can be classified into the following categories:

• Boiler water treatment

• Cooling water treatment

• Wastewater treatment

Water treatment is used to optimize most water-based industrial processes, such as: heating,cooling, processing, cleaning, and rinsing, so that operating costs and risks are reduced. Poorwater treatment lets water interact with the surfaces of pipes and vessels, which contain it. Steamboilers can scale up or corrode, and these deposits will mean more fuel is needed to heat thesame amount of water. Cooling towers can also scale up and corrode, but left untreated, thewarm, dirty water they can contain will encourage bacteria to grow, and Legionnaires ‘ diseasecan be the fatal consequence. Also, water treatment is used to improve the quality of watercontacting the manufactured product e.g. semiconductors, and/or can be part of the product e.g.beverages, pharmaceuticals, etc. In these instances, poor water treatment can cause defectiveproducts. Domestic water can become unsafe to drink if proper hygiene measures are neglected.

Waste Water Management – Proposed Concept

The ground water over consumption leads to the fall of water table. Domestic water supply(Villages/Towns/Cities) is mainly dependent on tube wells, artificial wells and streams or rivers.Lowering of the water table creates the crisis in domestic level and radically affects theagriculture. In order to optimize or reduce the waste and loss of drinking water, we have to takefew measures along with ECOSAN.

The diagrams below illustrate the idea by which the wastewater from domestic to the industriallevel can be stored after purification (natural/artificial). The idea behind this proposal is to storethe filtered water for reuse and recycle to both domestic and industrial domain as well as toreinforce the stored water by an artificial pressurizing mechanism into the water containing layerso that the overall level of water table rises to reach the artificial ground water pumpingequipments. This will also help to streams and rivers maintain their gross water flow level peryear and thus promoting irrigation.

The pressurizing equipments will be also stimulate the aqua ducts by increasing the pressuredepending upon the cross sectional area of the ducts and facilitate the normal water supply to theremote portions of an area. Lowering of water table basically reduces the aggregate of watercontent in the soil and beneath and thus reducing the water level throughout that zone. Thepurifiers should take care of the toxic content in the water as well as the harmful microbes. Thesefilters can be made by following the natural filtration processes along with enhanced chemicaltreatment with minimal contamination.

We should also keep our eye on one of the primary source of natural water that is rainwater. Therainwater is of drinkable quality and thus needs less effort to purify. This can reused for domesticpurpose and should try to permeate into the ground level than to let it fall in the local streams andrivers. The already present chemicals readily contaminate and raise the cost and effort forpurifications. This can be an alternative.

The graphical representations given in two sections depicting the idea visually.

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Waste Water Management-V1.0