In environmental engineering, sullage water refers to which of the following types of domestic waste water?

Introduction / Context:
In sanitation and environmental engineering, domestic waste water is often classified into two main categories: sullage and sewage. Understanding this distinction is important for designing drainage systems, treatment facilities, and public health measures. This question asks about the meaning of sullage water. Recognising that sullage refers to non toilet waste water from kitchens and bathrooms, while toilet waste is classified separately, is essential for basic environmental science questions.

Given Data / Assumptions:
– The term under discussion is sullage water, a type of domestic waste water.
– The options include water from kitchens, toilets, factories, and hospitals.
– We assume standard definitions used in basic environmental and civil engineering texts.
– The focus is on household waste water rather than industrial effluents.

Concept / Approach:
Domestic waste water can be divided into black water and grey water. Black water is sewage that contains human excreta from toilets. Grey water comes from kitchens, bathrooms, wash basins, and washing activities. In many texts, the term sullage is used almost synonymously with grey water and refers to domestic waste water that does not include toilet discharge. It may contain soap, grease, food particles, and dirt but does not contain significant amounts of faecal matter. Because the question uses simple options, the closest and most accurate description is waste water released from kitchen and bathrooms, excluding toilets. Waste water directly from toilets, from factories, or only from hospitals does not match the definition of sullage.

Step-by-Step Solution:
Step 1: Recall that sullage water is domestic waste water that does not contain toilet discharge and is therefore different from sewage or black water. Step 2: Identify common household sources for such water, including kitchens, bathrooms, and wash basins. Step 3: Recognise that waste water from toilets is considered sewage or black water and has a separate classification due to higher pathogen content. Step 4: Note that waste water from factories and hospitals involves industrial or institutional effluents and is not typically called sullage in basic school level definitions. Step 5: Conclude that sullage water refers to waste water from kitchens and bathrooms, not including toilets.

Verification / Alternative check:
Environmental engineering textbooks usually define sullage as waste water from bathrooms, kitchens, laundries, and wash basins, which may contain soap, detergents, oils, and food particles. They distinguish this from sewage, which includes toilet discharge and is more heavily contaminated with pathogens. Public health guidelines often discuss separate management of grey water and black water, where grey water parallels the idea of sullage. These consistent definitions confirm that sullage corresponds to non toilet domestic waste water, making the kitchen and bathroom option the correct one.

Why Other Options Are Wrong:
Waste water released directly from toilets: This is classified as sewage or black water and is not typically called sullage, because it contains human excreta and higher pathogen loads.
Waste water released from factories and industrial plants: This is industrial effluent, which has its own classification and treatment requirements and is not referred to as domestic sullage.
Waste water released from hospitals and clinics only: Hospital waste water may contain pharmaceuticals and biological contaminants and is treated as a special category of effluent, not as general household sullage water.

Common Pitfalls:
Students often confuse the terms sewage, sullage, and effluent and may assume that any dirty water is simply sewage. Another mistake is to associate sullage only with kitchens or only with bathrooms, ignoring that it generally covers all non toilet domestic waste water. To avoid such confusion, remember that sullage is essentially grey water and does not include toilet discharge, while sewage specifically includes black water from toilets. Keeping this clear division in mind helps you classify different types of waste water correctly in exam questions and real world contexts.

Final Answer:
Sullage water refers to waste water released from kitchen and bathrooms, excluding toilets, that is, non toilet domestic waste water.