International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 05 Issue: 05 | May-2018 www.irjet.net p-ISSN: 2395-0072 Design of Grey Water Treatment Units M.Seenirajan1, S.Sasikumar2, Erlin Antony3 1,2Asssociate Professor Department of Civil Engineering, Excel Engineering College, Komarapalayam , 3PG Environmental Engineering Student Excel Engineering College, Komarapalayam -----------------------------------------------------------------------***---------------------------------------------------------------------- Abstract: One way to conserve water is to find a safe way area is concentrated in a region such as flats, apartments to use it more than once. Grey water recycling is now or residential colonies, it is easy to collect the domestic accepted as sustainable solution to the general increase of waste water and to treat this for re-use. Meeting different the fresh water demand. Grey water refers to water that has needs with appropriate water quality may prove to be already been used in some way but which can be reused or economically more beneficial and at the same time reduce recycled in order to conserve fresh water. It is considered the needs for new supplies at a high margin (Halalsheh, relatively simple to treat grey water to make it safe for 2008). As per new building rules also, it is strict that each public use because of lower levels of contaminants. apartment should have a waste water treatment so that the water expelled to municipal waste after treatment In this paper we have taken into consideration the system can be reduced. So it will be reliable as well as possibilities of treating the grey water from our college sustainable technique to treat the domestic wastewater canteen and ladies hostel of the college. The process of and to reuse it for non potable purposes. In this chapter implementation included collection of waste water, sources, characteristics and various treatment methods of excluding black water, from college canteen and ladies grey water are discussed. hostel of the college. Various treatment units like storage tank, screen chamber, skimming tank, sedimentation tank, 1.1 GREY WATER COMPOSITION trickling filter, secondary clarifier and chlorination tank Grey water is the waste water generated in the bath were designed. room, laundry and kitchen. Grey water is therefore the component of domestic waste water, which has not This study highlights the conservation of fresh water in originated from the toilet or urinal. the campus, taking into consideration the increase in Grey water from bathrooms demand for fresh water. A partial break down of wastage of fresh water is expected to be accomplished through this Water used in hand washing and bathing generates paper around 50-60% of total grey water and is considered to be the least contaminated type of grey water. Common chemical contaminants include soap, shampoo, hair dye, Key words: Grey water, fresh water and black water toothpaste and cleaning products. It also has some faecal 1. INTRODUCTION contamination (and the associated bacteria and viruses) through body washing. Water pollution in many developing regions causes serious problems. The increase in population and Grey water from cloth washing the improvement of people’s daily life in these areas result Water used in cloth washing generates around 25- not only in an increase in volume of waste water, but also 35% of total grey water. Waste water from cloth washing in a change of waste water composition. Water varies in quality from wash water to rinse water to second conservation and reuse are becoming increasingly rinse water. Grey water generated due to cloth washing important as we now face serious problem including can have faecal contamination with the associated reduced ground water and surface water levels, droughts pathogens and parasites such as bacteria. and changing climatic pattern. Over 50% of the water demand from domestic and industrial applications could Grey water from kitchen be met by water of lower quality than fully treated water Kitchen grey water contributes about 10% of the including applications such as process water, toilet total grey water in volume. It is contaminated with food flushing etc. Substituting the quality water for non potable particles, oils, fats and other wastes. It readily promotes purposes to preserve high quality water resources is and supports the growth of micro-organisms. Kitchen grey highly efficient and practical, especially in arid region and water also contains chemical pollutants such as detergents developing countries. In most of cities since the housing © 2018, IRJET | Impact Factor value: 6.171 | ISO 9001:2008 Certified Journal | Page 4243 International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 05 Issue: 05 | May-2018 www.irjet.net p-ISSN: 2395-0072 and cleaning agents which are alkaline in nature and 2.1 Physical Characteristics of Grey Water contains various chemicals. Therefore kitchen waste water may not be well suited for reuse in all types of grey water Temperature systems. Grey water makes up to about 60-70% of Grey water temperature is often higher than that of domestic waste water volume. In terms of basic water the water supply and varies within a range of 18-30ºC. quality parameters, it is considered to be comparable to These rather high temperatures are attributed to the use low or medium grade waste water. As compared to of warm water for personal hygiene and discharge of domestic waste water, grey water tends to contain fewer cooking water. These temperatures are not critical for solids and is less turbid than all domestic waste water. The biological treatment processes (aerobic and anaerobic concentration of organics is somewhat similar to domestic digestion occurs within a range o 15-50ºC, with an optimal waste water. Their chemical nature is quite different. range of 25-35ºC). On the other hand, higher temperatures Soaps and detergents are often alkaline, so the pH of grey can cause increased bacterial growth and decreased CaCOз water is normally within the range of 6-8. Unlike waste solubility, causing precipitation in storage tanks or piping waters that contain higher concentrations of N, P and K, systems. only minor qualities of nutrients have been detected in grey water samples. Grey water composition varies widely Suspended solids from house hold, depending on personal habits of the Food, oil and soil particles from kitchen sinks, or residents and the products used in home. hair and fibres from laundry can lead to higher solids 2. CHARACTERISTICS OF GREY WATER content in grey water. These particles and colloids can cause turbidity in the water and may even result in The characteristics of domestic grey water are physical clogging of pipes, pumps and filter used in influenced by several factors, primary influences are treatment processes. Especially non-biodegradable fibres plumbing fixtures and appliances present as well as their from clothing (polyester, nylon, and polyethylene), frequency of use. Additionally the characteristics of powdered detergents and soaps, as well as colloids are the residing family in terms of number of family members, age main reasons of physical clogging. Suspended solids levels and mobility are important as in the overall socio concentrations in grey water range from 50-300 mg/L, but economic status of the family. Grey water contain can be as high as 1500mg/L. The highest concentrations of considerable amount of BOD, COD, turbidity, chlorides and suspended solids are typically found in kitchen and suspended solids. Biological oxygen demand of grey water laundry grey water. Suspended solids concentrations equals or may exceed that of black water. This is primarily strongly depend on the amount of water used. because of food waste and grease from the kitchen waste. Observations in Nepal, Malaysia, Israel, Vietnam and the Due to kitchen sink lows, total suspended solids may equal united states revealed average suspended solids loads of to those found in toilet water and will far exceed toilet 10-30 g/p/d, contributing to 25-30% of the total daily flows when garbage disposal is used. Grey water also suspended solids loads in domestic waste water, including contains a mixture of chemicals used in a variety of toilet waste water (Ledin et al., 2001). household products resulting in a complex chemical composition. The addition of household chemicals can also 2.2 Chemical Characteristics of Grey water change the bulk chemical characteristics of the water such The chemical parameters of relevance are hydro as pH, suspended solids, biological oxygen demand and chemical parameters such as pH, alkalinity, electrical conductivity. Grey water comprises about 60% of typical conductivity, sodium adsorption ratio (SAR), biological and household waste water flow. The physical, chemical and chemical oxygen demand (BOD, COD), nutrient microbial characteristics of grey water vary based upon content(nitrogen, phosphorus), and problematic the sources connected to the collection system, household substances such as heavy metals, disinfectants, bleach, composition as well as household chemical usage of the surfactants or organic pollutants in detergents. Certain residents (Eriksson et al., 2002). According to different studies reported the presence of personal care products, studies, grey water makes up on average more than half of medicines, hazardous organic pollutants etc in grey water the BOD load, up to two thirds of the total phosphorous (Erikson et al., 2002). load (where phosphate containing detergents are used) and one fourth of the total suspended solids load. This pH and alkalinity clearly reveals the importance of including grey water in The pH indicates whether a liquid is acidic or basic. For sanitation programmes. Focusing only on black water will easier treatment and to avoid negative impacts on soil and not meet the objective of providing adequate sanitation plants when reused, grey water should show a pH in the and reducing public health risks and environmental range of 6.5 - 8.4. The pH value of grey water, which degradation.