3.1. Effects of Discharge of Untreated Wastewater and Necessity to Treat Wastewater
In a study of Prüss-Ustün et al. [
17] developed based on data obtained from 145 countries, which estimated the burden of diarrheal diseases (such as cholera, typhoid and dysentery) from exposure to inadequate water, it was shown that in 2012, 502,000 diarrhoea deaths were caused by inadequate drinking water and 280,000 deaths by inadequate sanitation. Instead, the situation is not so dramatic in Romania.
The legal basis of EU wastewater legislation is represented by Council Directive 91/271/EEC of 21 May 1991 concerning urban waste-water treatment [
18], modified through Directive 98/15/EC [
19]. Directive 91/271/EEC was fully transposed into Romanian legislation through Government Decision no. 188/2002 on the approval of the rules on the conditions of discharge of wastewater in the aquatic environment (amended and supplemented by Government Decision no. 352/2005, Government Decision no. 210/2007) [
20]. Through the Treaty of Accession to the European Union, Romania obtained transition periods, so that by 31 December 2015, all agglomerations of more than 10,000 inhabitants complied with the provisions regarding the collection and advanced treatment of wastewater and until 31 December 2018 all agglomerations with 2000–10,000 inhabitants will have to comply with the collection and secondary treatment of wastewater (mechanical-biological treatment). Taking into account both the positioning of Romania in the Danube river basin and the Black Sea Basin and the need to protect the environment in these areas, Romania declared its entire territory as a sensitive area [
12]. This decision is reflected in the fact that agglomerations with more than 10,000 equivalent inhabitants have to provide an infrastructure for urban wastewater treatment that allows for advanced treatment, especially with regard to nitrogen and phosphorus nutrients (article 3(1) of Government Decision no. 352/2005 (Government of Romania, 2005)).
In 2016, in Romania, the total wastewater discharged was of 1940.98 million cubic meters, of which 1933.85 required treatment and of this quantity 83.74% were treated (36.46% improperly treated and 47.28% properly treated) [
21]. In the same year, there were 47 accidental pollutions due to the negligence of some economic operators caused during the technological processes or to the non-observance of the legal provisions regarding the discharge of wastewater into natural receptors [
21]. However, lack of education and the carelessness unpunished by authorities have turned many places of Romania into garbage dumps. For example, following inspection on 40 watercourses in the West of Romania, the Environmental Guard discovered ten such illegal landfills. They only gave one fine of about 21,000 Euros after a town hall covered with the bulldozer the garbage dumped in the Apuseni Natural Park [
22].
In relation to the necessity to treat wastewater, in a study of Lu et al [
23] it was shown that, in China, the deterioration of water quality by a single grade increases by 9.7% the digestive cancer death rate and it influences proliferation of “cancer villages”, which means, based on environmental pollution, that a village has a higher morbidity cancer rate than the average level [
24].
3.2. Effects of Waste Cooking Oil, Pharmaceuticals and Other Chemicals on Water Quality
Toxic organic pollutants found in waters are pesticides which include, for example, fungicides, insecticides, herbicides, halogenated aromatic hydrocarbons, formaldehyde polynuclear hydrocarbons, phenols, biphenyls, detergents, pharmaceuticals, oils and greases [
25]. Management of waste cooking oil (WCO) and fats from household and industry poses a significant challenge because of their disposal and contamination, especially of waters [
26]. Worldwide, with 500 million tons of WCO yearly produced, China is the largest producer of waste cooking oil [
27], while at EU level the total waste cooking oil production is about 700,000–1,000,000 tons/year [
28]. According to the European Biomass Industry Association [
29], it is estimated that, at EU level, 90% of cooking oil and fats are produced from vegetable oil and the potential WCO to be collected is around 8 L/capita/year; with an EU population of almost 500 million, the annual collection capacity is 4 Mton of WCO, which is seven times more than the current collected amount [
29]. One of the best ways to utilize WCO efficiently and economically is by converting it into biodiesel [
30] that is considered as a three-win solution, in terms of pollution, food security and energy security [
27,
28,
31]. Lack of information and education determine that this WCO is most of the time poured down the drain, resulting in problems for wastewater treatment plants.
Most EU countries defined unused and expired pharmaceuticals as “special waste”, “dangerous”, “hazardous”, or “problematic waste” in recognition of their special status [
32]. Pharmaceuticals are understood as chemicals used for human and veterinary purposes in diagnosis, treatment, alteration, or prevention of disease, health condition, or structure/function of a being, a definition that can be extended to illicit (recreational) drugs [
33]. Pharmaceuticals and personal care products (PCPs) comprise numerous chemical classes. Pharmaceuticals and PCPs contain a large and diverse group of organic compounds, including endocrine disrupting compounds and pharmaceutically active compounds [
34] with a significant impact on water ecology and human health [
35]. Current wastewater treatment procedures have the capacity to eliminate only partially Pharmaceuticals and PCPs and, therefore, they will be found in receiving waters or in the resulting sludge which is sometimes used as fertilizer [
36]. Pharmaceuticals and PCPS include products such as lipsticks, sun-screen agents, shampoos, hair conditioners, hair colours, deodorants, fragrances, toothpaste, soap and different compounds commonly present in household items (e.g., detergents, insect repellents) and they are used to improve the quality of our day-to-day life [
37,
38]. Triclosan and triclocarban are the two typical antimicrobial products found in pharmaceuticals and PCPs and detected in wastewaters [
39]. Nitro- and polycyclic-musks, musk ketone found in fragrances, methylbenzylidene camphor present in sun-screen lotions and parabens and isothiazolin derivatives used as preservatives in cosmetics are included in pharmaceuticals and PCPs and they are present as biological and chemical stabilization [
36].
For pharmaceuticals, sewage treatment plants represent a major point of entry to surface waters [
40,
41], as long as removal rates (which depend on physico-chemical characteristics of discharged medicines and type of treatment technology) for pharmaceuticals in wastewater treatment plants range from less than 10% to almost 100% [
42,
43]. Scientific evidence reveals a broad array of environmental impacts of pharmaceutical discharge, ranging from the fact that the presence of antibiotics in water may lead to antibiotic resistance [
44,
45] to dramatic effects on the aquatic ecosystem, for instance, due to the presence of ethinyl oestradiol, the active component of a common oral contraceptive, which leads to sexual development impairment and the feminization of male fish [
46,
47,
48]. Endocrine disruption is not limited to the presence of ethinyl oestradiol. Besides, there are several non-steroidal substances called xenoestrogens which mimic in part the function of oestrogens [
49,
50].
It stands to reason that increased attention was given to environmental impact of uncontrolled medicines disposal or to adherence in medicines taking. In contrast, there has been relatively little research on pharmaceutical wastage behaviour
per se. Although there are many pieces of EU legislation referring to pharmaceutical waste and authorities’ efforts (e.g., information and educational campaigns) are directed to avoid that unused or expired pharmaceutics are discharged in sinks or toilets, this behaviour is still common in Romania and worldwide. For example, in the United Kingdom, 12% of people dispose of unused or expired tablets via toilet or sink [
51], while in Lithuania the percentage of people with the same behaviour was of 14% of the interviewed citizens, both from urban and rural settlements [
52]. In Afghanistan, more than 10% of the respondents flushed the expired medications down the toilet or sink [
53]. In a study that investigated the storage and disposal habits of medications amongst 230 Serbian families, it was revealed that the most common method for disposal of medications in households was disposal in the garbage (85.6% [urban] and 74.5% [rural]) or toilet (8.7% [urban] and 6.4% [rural]) and burning of expired medications in the back yard of the home was also a common practice for medication disposal in rural households (13.8%) [
54]. The causes of medicines wastage are mainly the fact that people change their mind about taking the pharmaceuticals they have bought, they take only a part of them, or they replace their expired stocks [
55].
In Europe, the presence of pharmaceuticals in STP (sewage system plant) effluents was confirmed over time almost everywhere from the Czech Republic [
56], Serbia [
57], the Netherlands [
58], the United Kingdom [
59] or to Spain [
60]. In a study of Ferrary et al. [
61] that investigated the ecotoxicity of several human pharmaceuticals (carbamazepine, clofibric acid and diclofenac) based on samples of the effluents from four European countries (France, Greece, Italy and Sweden) that were collected for various STPs, showed, for example, that all tested pharmaceuticals were detected in the effluents and carbamazepine seemed to be the most dangerous compound for aquatic environment; this was based on its extremely low removal rate in STPs. A study carried out in Italy assessed efficiency and identified the factors affecting the removal of 26 pharmaceuticals (that fall within the category of anti-inflammatory and cardiovascular drugs, antibiotics, gastrointestinal and diuretics drugs, lipid regulators) in STPs; total amount of those pharmaceuticals discharged into the environment ranged between 60 and 180 kg/day [
62]. Huerta-Fontela et al. [
63] studied occurrence of 55 pharmaceuticals, hormones and metabolites in raw waters used for drinking water production and they found that effectively drinking treatment removed 30 out of 35 investigated pharmaceuticals and that phenytoin, atenolol, sotalol, hydrochlorothiazide and carbamazepine epoxide were detected in discharged waters. In Romania, Chitescu et al. [
64], based on twenty samples of Danube water and three of the main tributaries, studied the occurrence of 67 pharmaceuticals and antifungals in the Danube river and observed that diclofenac reached the highest concentration.
Another group of bioactive chemicals with significant negative impact on environment is found in PCPs. The main source of PCP infusion into the environment is through STPs [
39] and conventional wastewater treatment processes are not sufficient for PCPs removal as indicated by Santos et al. [
65]. Escher and Fenner [
66] found out that transformation of PCPs occurs in wastewater treatment processes, sediments, soils, or drinking water treatment processes. In China, for example, the adsorbed and dissolved concentrations of nine PCPs were investigated in various wastewater treatment plants and it was showed that they were largely present in dissolved form in the raw influent and in the final effluent [
67].